Bulletin of the American Physical Society
42nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 56, Number 5
Monday–Friday, June 13–17, 2011; Atlanta, Georgia
Session Q1: Poster Session III (4:00 pm  6:00 pm) 
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Room: Atrium Ballroom BC 

Q1.00001: COLD ATOMS, MOLECULES AND PLASMAS III 

Q1.00002: Alloptical 87Rb Bose Einstein condensation in ultralow magnetic field Joshua Hughes, Matthew Williams, Chad Fertig We discuss recent experiments in a new, alloptical 87Rb BEC machine in which the UHV cell and trapping optics are fully enclosed by large volume ($\sim 1 m^3$) 5layer mumetal shield. Several novel aspects of the apparatus will be discussed, including the design and performance of the mumetal shield, the doubleMOT design and optically guided coldatom source, and novel ``scissor'' dipole trap formed by two 35W, 1064nm laser beams having a dynamically tunable crossing angle. Recent results and future experiments on spinor 87Rb condensates possible in the ultralow magnetic noise environment of this apparatus will be discussed. [Preview Abstract] 

Q1.00003: Progress towards a ``blue'' potassium MOT David McKay, Dan Fine, Dylan Jervis, Graham Edge, Joseph Thywissen One difficulty when preparing quantum degenerate gases of potassium 40 is the low efficiency of subDoppler cooling. In this talk, we discuss how we are attempting to circumvent this problem by implementing a ``blue'' MOT for $^{40}$K on the noncycling 4S$_{1/2}\rightarrow$5P$_{3/2}$ transition, which has a wavelength of 404.53nm and a decay rate of 1.17MHz. The Doppler temperature should be 27$\mu$K, which is a factor of five improvement over the D2 transition at 767nm. This lower temperature would also facilitate insitu imaging of atoms in optical lattices. The laser setup consists of a cooled diode injection locked to an external cavity diode laser. The master laser is in turn locked to $^{39}$K saturation spectroscopy in a heated vapor cell. The proximity of this 4S5P transition to the wavelength used in ``Bluray'' technology provides a relatively inexpensive source of laser diodes with powers up to 150mW. A dual MOT will be implemented using dichroic mirrors and waveplates for loading and capture with 767nm, followed by a switch to a ``blue'' MOT for latestage cooling before loading into a magnetic trap. We will also present results on the spectroscopy of the $^{40}$K 5P$_{3/2}$ hyperfine levels using our setup. [Preview Abstract] 

Q1.00004: Towards magnetic trapping of CaH Matthew Wright, HsinI Lu, Julia Rasmussen, Dave Patterson, John Doyle We propose a general technique to load molecules from a cryogenic buffergas cooled beam into a magnetic trap. The technique uses one or two optical pumping stages (one photon absorbed per stage per molecule) to continuously and irreversibly load the trap from a slow beam. The method is general and does not rely on unusual level structures or closed transitions. As a step toward this goal, we have demonstrated an intense, cold molecular beam source of CaH. The beam consists of approximately 10$^9$ molecules moving in a nearly effusive source under 3K. We will discuss progress towards magnetically guiding the molecules to provide a clean, stateselected beam source. The technique is expected to allow the observation of collisions, and consequent cooling in an extremely high vacuum environment. [Preview Abstract] 

Q1.00005: Cold Rydberg atom collisions in a dipole trap Jader Cabral, Luis Gon\c{c}alves, Jorge Kondo, Luis Marcassa We have built a new experimental setup to investigate cold Rydberg atom collision in a high atomic density sample in a CO$_{2}$ dipole trap. Briefly, we load a Rb standard magnetooptical trap from an atomic vapor provided by a dispenser. Then we turn on 100W CO$_{2}$ dipole trap and we apply a loading phase, in which the repumper light intensity is reduced. After this phase, the trapping and repumper laser beams are turned off and we wait 100ms for the atoms that were not trapped to fall off the dipole trap region due to gravity. Finally, we turn off the dipole trap and excite the Rydberg state using a two photon transition. The Rydberg atoms are detected using pulsed field ionization technique. In this new setup, we can image the ions onto a MCP detector to study the spatial distribution. The electrons maybe detected also by another MCP. During the presentation we shall present preliminary results involving the excitation of nD+nD states. [Preview Abstract] 

Q1.00006: Transporting nearcircular Bohrlike wave packets using chirped pulse trains S. Yoshida, J. Burgd\"orfer, C.O. Reinhold, B. Wyker, S. Ye, F.B. Dunning Protocols for driving localized high$n$ ($n$~300) wave packets in nearcircular Bohrlike orbits to higher $n$ states using chirped sine waves are described. While Rydberg wave packets involving several $n$ levels are known to be dispersive, circular wave packets can be stabilized by the application of a circularly or linearly polarized resonant sine wave. A similar stabilization mechanism is known for the formation of the Trojan asteroids in celestial mechanics. We demonstrate that by slowly chirping the drive frequency parent high$n$ wave packets can be transported to a narrow distribution of much higher $n$ states because the motion of the wave packet remains locked to the sine wave during the chirping. Use of a chirped HCP train instead of a sine wave allows similar transport but also provides some control of the orbit eccentricity. Research supported by the NSF, the Robert A. Welch Foundation, the OBES US DoE to ORNL, and by the FWF (Austria) [Preview Abstract] 

Q1.00007: Fewbody Cs Rydberg Atom Interactions in a 1064nm Dipole Trap Donald Booth, Jonathan Tallant, Bruno Marangoni, Luis Marcassa, James Shaffer In studying fewbody physics, the number density of atoms is an important parameter in achieving a good signal to noise ratio. We have recently improved our apparatus by implementing a crossed $1064 \mathrm{nm}$ far offresonance trap (FORT), which enables us to trap atoms at three orders of magnitude greater density than our MOT. Future directions for the apparatus, which include the study of anisotropic interactions among Rydberg atoms in the dipole trap, threebody recombination, ``trilobitelike" molecules, and the detection of ultralong range Rydberg macrodimers in Cs, will be described. Our presentation will focus on data on threebody recombination and longrange Rydberg ``trilobitelike" molecules. [Preview Abstract] 

Q1.00008: Ultralongrange polyatomic Rydberg molecules formed by a polar perturber Michael Mayle, Seth T. Rittenhouse, Peter Schmelcher, Hossein R. Sadeghpour The internal electric field of a Rydberg atom electron can bind a polar molecule to form a giant ultralongrange polyatomic molecule [1]. Such molecules not only share their properties with Rydberg atoms, they possess huge permanent electric dipole moments and in addition allow for coherent control of the polar molecule orientation. The involved binding mechanism stems from the anisotropic, longrange chargedipole interaction that couples a set of $(n+3)s$ Rydberg states with the $n(l>2)$ nearly degenerate Rydberg manifolds in alkali metal atoms [2]. The resulting avoided crossings in the BornOppenheimer potentials enable the formation of the giant polyatomic Rydberg molecules with standard twophoton laser photoassociation techniques.\\[4pt] [1] S.~T.\ Rittenhouse and H.~R.\ Sadeghpour, Phys.\ Rev.\ Lett.\ {\bf104}, 243002 (2010).\\[0pt] [2] S.~T.\ Rittenhouse, M.\ Mayle, P.\ Schmelcher and H.~R.\ Sadeghpour, arXiv:1101.5353v1 [physics.atomph]. [Preview Abstract] 

Q1.00009: Experimental Investigation of Longlived ``ZEKE'' Rydberg States in Ultracold Argon G. Ranjit, C.I. Sukenik Ultracold plasmas are typically formed by photoexcitation of ultracold atoms to an energy region near an ionization threshold. Excitation to highlyexcited Rydberg states can lead to formation of a plasma via several processes, including collisions between the Rydberg atoms. Understanding the dynamics of ultracold Rydberg gases is therefore important for understanding the dynamics of ultracold plasmas. We will report on our study of a particular class of Rydberg atoms, known as ZEKE state Rydberg atoms, which are high angular momentum excited states formed by laser excitation in the presence of electric fields. We have investigated the creation and survival of ultracold ZEKE Rydberg states of argon in a MOT as function of principal quantum number for excitation to an energy region just below the second ionization threshold of the atoms. Here, low angular momentum states decay very quickly by autoionization, but ZEKE states live orders of magnitude longer because the high l, m Rydberg electron does not approach the core and autoionization is therefore suppressed. [Preview Abstract] 

Q1.00010: The Effect of Energy Level Structure on ManyBody Interactions among Rydberg Atoms Thomas Carroll, Jon Ward, Alexander Mellus, Michael Noel Ultracold highlyexcited atoms in a magnetooptical trap are strongly coupled by the dipoledipole interaction. We have developed a computational model of systems of Rydberg atoms in order to study the manybody nature of the interactions, the effect of the spatial arrangement of the atoms, and the energy level structure of the atoms. The model has been implemented on a parallel computer and can simulate experimentally realizable systems including 1020 atoms. In this work, we focus on a system with two nearly degenerate initial states. We examine the time evolution and the dependence of the interactions on the size of the energy gap between the initial states. [Preview Abstract] 

Q1.00011: Ion acoustic waves in Ultracold Plasmas Daniel Vrinceanu Acoustic waves can be induced by modulating the initial density of ions created from photoionization of cold atoms. A complete modeling of this system requires long Molecular Dynamics Simulations (milliseconds) for a large number of particles (billions). Such extraordinary computational power is still not available. This paper proposes a kinetic model, in which the evolution of the ion distribution function is obtained by numerically solving the Vlasov equation. At every time step, the average electric field is obtained by solving a quasiequilibrium problem for the electrons. Because of fast equilibration times, the electron gas assumes its stationary distributions in times much shorter than the typical ion time scale. A special distribution, similar to the King distribution used to model globular clusters of stars, is used to derive the equilibrium distribution of electrons before each ion time step. Numerical examples are presented. [Preview Abstract] 

Q1.00012: Observation of a density spike in the ion distribution of an ultracold plasma R.A. Perrotta, K.A. Twedt, S.L. Rolston Expanding ultracold neutral plasmas are predicted to have a broad spike in the ion density distribution at the leading edge of the plasma. This feature forms as a result of a slight positive charge imbalance created by the prompt loss of electrons at plasma creation. We monitor the flux of ions passing through a grid in our vacuum chamber during the plasma expansion and the observed signal is fit well by a model of a spherical Gaussian cloud ballistically expanding through a circular planar grid. The shape of the initial flux indicates that the leading edge of the plasma has a sharp density cutoff rather than a smooth Gaussian tail. This feature is accentuated by applying a magnetic field perpendicular to the detection axis, slowing down the expansion of the neutral plasma relative to the ion spike. Supported by NSF PHY 1004242. [Preview Abstract] 

Q1.00013: Detection of Rydberg States of Helium by Black Body Ionization Xiaoxu Lu, Yuan Sun, Harold Metcalf We are studying the detection of He Ryberg atoms excited in two steps from the metastable 2$^3$S state (He*). The lower transition connects to the 3$^3$P state via $\lambda$ = 389 nm light and the upper one to the $n,\ell$ states via $\lambda$ = 785  815 nm ($n \sim 13  45$). The He* atoms in a thermal beam ($v \sim$ 1070 m/s) cross the two laser beams at 90$^{\rm o}$ and they are arranged for the STIRAP excitation process: atoms encounter the red light before the blue. The excitation is between two large (7 $\times$ 17 cm) plates 6 mm apart that can be used to apply an electric field for Stark spectroscopy or field ionization, or be heated to provide a blackbody radiation bath. An ion detector readily detects the presence of Rydberg atoms and we have made several Stark maps that agree well with calculated energies. We believe the observed signals are produced by blackbody ionization at a very low rate, but sufficient to ionize less than 1\% of the atoms in a region viewed by our detector. Many measurements provide support for this hypothesis. [Preview Abstract] 

Q1.00014: Absolute Efficiency for STIRAP Excitation of Rydberg States X. Lu, Y. Sun, H. Metcalf We have developed a method for measuring the absolute efficiency for two step STIRAP excitation of Rydberg states. A beam of metastable 2$^3$S state He atoms crosses two laser beams at 90$^{\rm o}$ that can be displaced to vary their order of encounter by the atoms. The lower transition connects to the 3$^3$P state via $\lambda$ = 389 nm light and the upper one to the $n,\ell$ states via $\lambda$ = 785  815 nm ($n \sim 13  45$). In the STIRAP process, atoms encounter the red light before the blue. Data from an ion detector enables us to make Stark maps that agree well with calculated energies. Several mm downstream of the interaction region we apply the very strong bichromatic force\footnote{M. Partlow et al., Phys. Rev. Lett. {\bf 93} 213004 (2004) and its references.} on the 2$^3$S $\rightarrow$ 2$^3$P transition at $\lambda \,$= 1083 nm. It deflects the remaining 2$^3$S atoms out of the beam and the ratio of this signal measured with STIRAP beam on or off provides an absolute measure of the fraction of the atoms remaining in the 2$^3$S state (most Rydberg atoms don't decay to 2$^3$S during this short flight distance). Simple threelevel models of STIRAP all predict 100\% excitation probability, but our measurements are typically less than half of this, and vary with both $n$ and $\ell$ of the Rydberg states selected for excitation by the laser frequency and electric field tuning on our Stark maps. We are surprised by this result. [Preview Abstract] 

Q1.00015: Toward internal cooling of trapped molecular ions using a spinorbit split ground state V. Rajagopal, J.P. Marler, L.C. Ruth, C.M Seck, B.C. Odom Preparation of stateselected trapped molecular ensembles is a promising starting point for precision measurements on trapped molecular samples. Translational cooling of trapped molecular ions can be accomplished sympathetically by laser cooling a cotrapped atomic species. To date, in situ cooling of rotational degrees of freedom has been demonstrated only for polar hydrides, by optical pumping into an excited vibrational level. ~However, with increasing reduced mass, the time for vibrational relaxation within the ground state increases, making this scheme problematic for heavy species. We introduce a new cooling scheme, exploiting the diagonal FranckCondon factors present for molecular ions with spinorbit split ground states, applicable to certain heavy as well as nonpolar species. Progress towards the experimental realization of this scheme for cooling IF{\$}\^{}+{\$}, including the molecular ion production technique, details of the statepreparation, and the proposed stateresolved detection scheme will be discussed. [Preview Abstract] 

Q1.00016: Strong Optical Force Measurements Using Adiabatic Rapid Passage Dan Stack, John Elgin, Harold Metcalf Adiabatic Rapid Passage (ARP) is most robust in the parameter domain $\Omega_0 \sim \delta_0 \gg \omega_m \gg \gamma$ where $\Omega_0$, $\delta_0$, and $\omega_m$ are the Rabi frequency, sweep range, and sweep rate respectively. Previous experimental work\footnote{X. Miao et al., Phys. Rev. A {\bf75}, 011402 (2007).} has shown that very strong, long range optical forces can be produced on the 2$^3$S $\rightarrow$ 2$^3$P transition in He through the use of ARP sequences in an unconventional parameter domain . These optical forces rely on the coherent momentum exchange between the atoms and the light field. We expand on this work to include the use of independent counter propagating optical beams which allow for increased control of the experimental parameters, such as Doppler detuning to simulate the velocity of moving atoms. We present our experimental setup and our investigation of the velocity dependence of this large optical force. [Preview Abstract] 

Q1.00017: Numerical Studies of Optical Forces from Multiple Adiabatic Rapid Passages Dan Stack, John Elgin, Petr M. Anisimov, Harold Metcalf In previous experimental work we exploited coherent momentum exchanges between light fields and atoms to produce longrange optical forces much greater than the radiative force through the use of absorptionstimulated emission processes.\footnote{X. Miao et al., Phys. Rev. A {\bf75}, 011402 (2007).} One such way is through the use of multiple adiabatic rapid passage sequences on the $2^3$S $\rightarrow 2^3 P$ transition in helium. In this work we study numerical solutions for the optical Bloch equations that show the dependence of such optical forces on the pulse durations, sweep ranges, peak Rabi frequencies, sweep directions, relative phases, and overall phase stability. The velocity dependence of this force as well as the effects of spontaneous decay from the excited state has also been examined under various conditions. We have been surprised by some curious phenomena but have found intuitively satisfying explanations in terms of the motion of the Bloch vector on the Bloch sphere. [Preview Abstract] 

Q1.00018: Speckle Imaging of Degenerate Fermi Gases Edward Su, Wujie Huang, Christian Sanner, Aviv Keshet, Jonathon Gillen, Wolfgang Ketterle We develop a technique for measuring the fluctuations in the total and relative density of twocomponent gases, based on the dispersive imaging of speckle patterns. The compressibility and susceptibility can be extracted from the measured fluctuations. Using this technique, we study the pair correlations of strongly interacting Fermi gases, both in the BECBCS crossover and in the case of strong repulsive interactions. [Preview Abstract] 

Q1.00019: Universal Thermodynamic and Spin Transport Properties of Strongly Interacting Fermi Gases Ariel Sommer, Mark Ku, Lawrence Cheuk, Martin W. Zwierlein We perform a highprecision measurement of the equation of state of a Fermi gas with unitarity limited interactions by in situ imaging of ultracold $^6$Li at a Feshbach resonance. We observe the superfluid phase transition in the chemical potential, entropy, compressibility and heat capacity, and provide a new value of the Bertsch parameter $\xi_S$. In a separate set of measurements, we determine the spin transport properties of strongly interacting Fermi gases by spatially separating the two spin components and allowing the system to relax to equilibrium (arXiv:1101.0780v1). We find that the spin diffusivity approaches a universal minimum value set by the ratio of Planck's constant to the atomic mass, and determine the spin susceptibility from spin transport properties. [Preview Abstract] 

Q1.00020: Rapid production of spinor quantum fluids Lauren Aycock, Srivatsan Chakram, Mukund Vengalattore Quantum degenerate spinor gases, with their interplay between superfluidity and magnetism, offer rich prospects for the study of quantum magnetism [1], nonequilibrium physics [2], and quantum metrology [3]. As has been shown [4], these studies are aided by the creation of large, spatially extended ensembles of condensed gases. Furthermore, metrological applications of these fluids require an apparatus capable of a rapid duty cycle. Using a combination of novel cooling techniques such as degenerate Raman sideband cooling [5] and alloptical evaporation, we are implementing a multispecies spinor gas apparatus capable of generating large quantum degenerate ensembles within 1 second. We present our design and characterization of this apparatus, and outline experimental studies that will be undertaken in the immediate future. In addition, we comment on adaptation of these techniques to atomic species that have proved less amenable to traditional methods of cooling. \\[4pt] [1] M. Ueda and Y. Kawaguchi, arXiv:1001.2072 [2] Polkovnikov et al., arXiv:1007.5331 [3]M. Vengalattore et al, Phys. Rev. Lett. 98, 200801 (2007) [4] M. Vengalattore et al, Phys. Rev. Lett. 100, 170403 (2008), M. Vengalattore et al, Phys. Rev A 81, 053612 (2010) [5]V. Vuletic, C. Chin, A. J. Kerman, and Steve Chu, Phys. Rev. Lett. 81 5768 (1998) [Preview Abstract] 

Q1.00021: Harnessing modulational instability for the generation of vector solitons Peter Engels, JiaJia Chang, Chris Hamner We investigate the formation of solitons in elongated BoseEinstein condensates. Counterflowinduced modulational instability is introduced as an effective tool to generate vector solitons in a twocomponent BEC that have no analog in singlecomponent systems. The current status of the experiment will be discussed. [Preview Abstract] 

Q1.00022: Finessing the Exponential Scaling with N Problem for Manybody Systems Deborah Watson, Martin Dunn The resources required for an exact solution of the general quantum mechanical $N$body problem are widely believed to scale exponentially with $N$, typically doubling for every particle added. With current numerical resources, this problem ``hits a wall'' around $N=10$ (within a factor of 2). We have formulated a perturbation method for the general $N$boson problem that uses symmetry to {\it rearrange} this exponential wall so the problem scales as $N^0$. This is achieved by using a perturbation expansion that is invariant under the $N!$ operations of the symmetric group $S_N$, allowing group theory and graphical techniques to be used to solve the problem exactly and analytically at each order for arbitrary interactions and for arbitrary $N$, i.e. the problem scales as $N^0$ at each order. This approach also shifts the work from numerical effort for a single $N$ to analytic work valid for all $N$. The exponential complexity reappears in an exponential wall that scales with the order of the series. We have investigated the growth of complexity as a function of order by enumerating the graphs that correspond to the basis tensors at each order. This formulation opens up the possibility of exact analytical calculations for very large $N$ systems through low order. [Preview Abstract] 

Q1.00023: Fast production of large sodium BoseEinstein condensates Jaeyoon Choi, MyoungSun Heo, Woo Jin Kwon, Yongil Shin We have realized BoseEinstein condensates (BEC) of sodium atoms in an optically plugged magnetic quadrupole trap. Our BEC machine employs a zerocrossing Zeeman slower to provide a high atom flux and a magnetic quadrupole, linear trap for fast rethermalization during evaporation cooling. The Majorana nonadiabatic spinflip loss, which is the major defect of a quadrupole trap, was suppressed by superposing a repulsive optical potential at the magnetic trap center. A large pure condensate of 10 million atoms was produced in every 17 s. We have obtained quantitative understanding of the fast and efficient evaporation by investigating the heating and loss effects of the Majorana spin flip and the optical plug. A simple model will be presented to describe the evaporation dynamics in the plugged quadrupole trap. [Preview Abstract] 

Q1.00024: Harmonically trapped Bose gases: Weaklyinteracting regime and beyond K.M. Daily, D. Blume There exist few exactly solvable problems in physics, but they tend to serve as useful benchmarks and starting points for understanding more complex phenomena. We study dilute harmonically trapped fewboson systems with twobody swave interactions and present highly accurate results for the energetics and the condensate fraction. Using the exact twobody wave function, we calculate the condensate fraction by diagonalizing the onebody density matrix as a function of the twobody swave scattering length $a_s$. We find that the condensate fraction exhibits an interesting oscillatory behavior. In the weaklyinteracting regime, we analytically expand the condensate fraction in terms of $a_s$. For the weaklyinteracting threebody system, our numerical results for the energy agree with the analytical predictions of Ref. [1] and, furthermore, allow for the extraction of higher order corrections. In addition, we determine the condensate fraction of weakly and stronglyinteracting threeboson systems. Extensions to larger systems and an interpretation in terms of effective $N$body interactions are presented.\\[4pt] [1] P. R. Johnson, E. Tiesinga, J. V. Porto and C. J. Williams, New J. Phys 11, 093022 (2009). [Preview Abstract] 

Q1.00025: The Effects of Disorder on a Quasi2D System of Ultracold Atoms Matthew Beeler, Matthew Reed, Tao Hong, Steven Rolston An ultracold gas of atoms can be used to create many different model Hamiltonians. When tightly confined in one spatial dimension, the gas can become effectively twodimensional. At low temperature, a quasi2D Bose gas undergoes a Berezinskii KosterlitzThouless phase transition to a superfluid, mediated by the binding and unbinding of vortex pairs. As disorder affects vortex transport properties, a slight amount of fine grain disorder in the potential energy may alter the properties of this phase transition. We will present experimental observations of a 2D Bose gas of rubidium atoms in the presence of disorder created by a laser speckle field. [Preview Abstract] 

Q1.00026: $^{39}$K BoseEinstein condensates in two and three dimensions with tuneable interactions Robert Campbell, Robert Smith, Naaman Tammuz, Scott Beattie, Stuart Moulder, Zoran Hadzibabic We report on the production of $^{39}$K BoseEinstein condensates of over $4\times10^5$ atoms with broadly tuneable interactions [Campbell et al., Phys. Rev. A \textbf{82}, 063611 (2010)]. Condensation is achieved via a combination of sympathetic cooling with $^{87}$Rb in a QUIC magnetic trap and direct evaporation in a largevolume crossed optical dipole trap, where we exploit the broad Feshbach resonance at 402.5 G to tune the $^{39}$K interactions from weak and attractive to strong and repulsive. We also discuss the progress of our experimental investigation into the role of interactions on the low temperature behaviour of twodimensional Bose gases. [Preview Abstract] 

Q1.00027: Prospects for Observation of a TonksGirardeau Gas in an Atom Chip Waveguide Jason Alexander, Violeta Prieto, Chris Rowlett, Patricia Lee, William Golding Bosons confined in (quasi) one dimension can enter a new state of matter, a TonksGirardeau gas, in which they behave like noninteracting fermions when the atomatom repulsive interaction becomes much larger than the kinetic energy. However they can occupy the same momentum state and therefore the gas cannot be fully described by either BoseEinstein or FermiDirac statistics. The phase transition requires the combination of a highly anisotropic trapping potential, low temperature and a low density of atoms. Recently there has been evidence of this state of matter in optical lattices.\footnote{Paredes et al. \textit{Nature} \textbf{429}, 277281 (2004), Kinoshita et al \textbf{305 }1125 \textit{Science} (2004)} However, attempts to observe this state in magnetic atom chip waveguides have yet to meet success. We discuss the conditions for obtaining such a phase transition with $^{87}$Rb atoms in our atom chip waveguide, propose a novel signature for the transition to a TonksGirardeau gas and discuss several independent methods of observing this signature in our system. [Preview Abstract] 

Q1.00028: Ultracold Mixtures and Molecules from Ytterbium and Lithium Anders Hansen, Alexander Khramov, William Dowd, Alan Jamison, Vladyslav Ivanov, Frank M\"unchow, Subhadeep Gupta Ultracold mixtures composed of different atomic species offer unique opportunities for probing few and manybody physics, including studies of massmismatched Efimov physics, impurity probes of superfluid properties, and massimbalanced interactions. Furthermore, the possibility of producing heteronuclear, polar molecules through fieldinduced scattering resonances enables a large set of experiments involving dipolar quantum matter and tests of fundamental physics. We outline our experimental setup and techniques to synthesize molecules from ultracold gases of atomic lithium and ytterbium. We report on the production of a stable mixture of $^{6}$Li and $^{174}$Yb confined in a common faroffresonant optical trap. Through studies of interspecies thermalization rates, we have extracted the swave scattering length $a_{^{6}Li^{174}Yb}$. Furthermore, through forced evaporation of $^{174}$Yb, we have sympathetically cooled $^{6}$Li to below the Fermi temperature. We will discuss experimental progress towards searches for interspecies Feshbach resonances, the synthesis of polar molecules, and studies of the BECBCS crossover in $^{6}$Li using $^{174}$Yb as an impurity probe. [Preview Abstract] 

Q1.00029: Lowenergy Behavior of Quantum Defect Parameters for Longrange Potentials Brandon Ruzic, John L. Bohn Ultracold collisions of atoms have been successfully described within various versions of quantum defect theory. One particular standardization of longrange reference functions in a van der Waals potential has proven quite useful over a wide range of energy and magnetic field [1]. We extend the use of this standardization to describe a variety of atomic and molecular collisions governed by mixed longrange potentials and explore perturbation theory as a means of describing the lowenergy behavior of these parameters. In particular, longrange dipolar forces between polar atoms or molecules may be described in a simplified way. This research is supported by the DOE.\\[4pt] [1] J.P. Burke, Jr., C. H. Greene, and J. L. Bohn, Phys. Rev. Lett. 81, 3355 (1998) [Preview Abstract] 

Q1.00030: Modeling ion dynamics for BECion interaction experiments Andrew T. Cadotte, David A. Anderson, Georg Raithel We present simulations of Coulomb repulsion effects in an experiment designed to study BECion interactions. Since the studies require free charged particles, Coulomb effects are expected to have a nonnegligible influence on the observed ion dynamics. ~In our simulations, we assume an ion extraction electric field generated by a small, circular electrode (diameter 100 micron) embedded in a grounded plate. To model ion trajectories, a RungeKutta method is used. A triangular interpolation method is employed to obtain the extraction electric field values along the ion trajectories. ~To describe the dynamics of a few, discrete ions during extraction, we explicitly sum over all Coulomb interaction terms. To consider the extraction behavior of many ions, we model the system by a continuous charge distribution. The results serve as a guide for experimental studies. [Preview Abstract] 

Q1.00031: Ultracold inelastic threebody collision rates for different twobody potentials with identical spectra Edmund Meyer, Brett Esry We present a computational study of the way in which threebody observables differ for systems with identical twobody bound state energies and phase shifts. Using standard techniques arising from supersymmetric quantum mechanics~[1], we construct a twobody potential with identical phase shifts, but different numbers of bound states. We consider model potentials with masses corresponding to Yb+Yb+H as an example. The mass ratio between Yb and H makes the computation much simpler. We scan through a large range of the twobody scattering length (identical for each potential) and note the differences in threebody loss rates. \\[4pt] [1] D. Baye and J.~M. Sparenberg, Phys. Rev. Lett. 73, 27892792 (1994) [Preview Abstract] 

Q1.00032: Optical Feshbach Resonances in $^{88}$Sr Travis Nicholson, Sebastian Blatt, Benjamin Bloom, Jason Williams, Jun Ye, Paul Julienne We recently demonstrated that the accuracy and precision of strontiumbased optical lattice clocks can be improved by an order of magnitude with control over manybody physics [1]. Greater manybody control via Feshbach resonances is desired, but magnetic Feshbach resonances do not exist in the strontium ground state. However, optical Feshbach resonances have been indirectly observed through atom loss spectra [2]. To date most optical Feshbach resonance theory has approximated photoassociation lines as isolated [3]. For large detunings from these lines, this theory predicts big scattering length changes with minimal inelastic lossesyet we did not experimentally observe elastic effects at large detunings [4]. We present new optical Feshbach resonance calculations that do not make the isolated resonance approximation, showing that this approximation is valid near a photoassociation line but not at large detunings. In the context of this new theory, a systematic experimental study of optical Feshbach resonances will be also presented, including detailed measurements of the Sr+Sr dimer structure and the first direct observation of lightinduced thermodynamics. [1] M.D. Swallows et al., Science, 3 Feb 2011 (10.1126/science.1196442) [2] G. Thalhammer et al., Phys Rev A \textbf{71}, 033403 (2005) [3] J.L. Bohn and P.S. Julienne, Phys Rev A \textbf{60}, 414 {1999} [4] R. Ciurylo et al., Phys Rev A \textbf{71}, 030701 {2005} [Preview Abstract] 

Q1.00033: Threebody Efimov physics near a narrow Feshbach resonance with a large background scattering length Fatima Anis, Yujun Wang, B.D. Esry We study threebody Efimov physics near a narrow Feshbach resonance that lies on top of a broader one. We have modelled the twobody interactions with a singlechannel potential to reproduce the twobody physics of such overlapping resonances and have performed threebody calculations for various resonance parameters. In particular, we study Efimov physics as a function of the scattering length for the narrow resonance when there is a large background scattering length. The Efimov features near an isolated, broad Feshbach resonance can be universally identified by a sequence of minima or peaks in the threebody recombination rates for the positive or negative twobody scattering length, respectively. In the present study, we try to identify the universal threebody physics for the overlapping and narrow resonances. [Preview Abstract] 

Q1.00034: Universal threebody physics at finite energies Yujun Wang, J.P. D'Incao, B.D. Esry, Chris H. Greene We discuss the universal threebody scattering physics for cold atoms up to energies far beyond the ultracold limit. We have found universal features in the energydependence of the threebody recombination rates which can be traced to Efimov physics. These new features, however, have different character for positive and negative scattering length ($a$) because the high partial wave contributions are very different. In particular, we show that for $a>0$, the very high partial wave contributions are still important in a certain energy range. For $a<0$, however, the $S$wave contribution is dominant up to the highest energy where the threebody recombination is universal. We also discuss modifications of the universal threebody physics that arise near a narrow Feshbach resonance. Our results provide a complete picture for the universal features in the threebody recombination, and will assist the experimental study of the universal threebody physics under very different experimental conditions. [Preview Abstract] 

Q1.00035: Investigating Transport Phenomena with Trapped Ion Strings Thaned Pruttivarasin, Michael Ramm, Axel Kreuter, Hartmut Haeffner Trapped lasercooled ion crystals are well controllable coulomb coupled oscillators that present an ideal experimental setting for a variety of quantum simulations. We study the energy transfer dynamics within long ion chains when one end of the crystal is heated strongly by a thermal bath of variable temperature. The bath can be engineered using focused laser beam with variable detuning of the S1/2P1/2Doppler cooling transition of 40Ca+. The local temperature of the chain can be probed by monitoring the fluorescence of another focused laser beam. We report on the experimental progress towards this scheme and give a brief outlook for further experiments that involve a superimposed optical lattice and aiming at observing a quantum phase transition associated with the additional optical potential. In particular, we plan to investigate the heating and cooling dynamics within crystals of several tens of 40Ca+ ions. [Preview Abstract] 

Q1.00036: Dynamics of Quantum Phase Transitions and the KibbleZurek Mechanism Jennifer Patterson, Michael Wall, Lincoln Carr We study the dynamics of quantum phase transitions (QPT's) for a system of spin1 bosons on an optical lattice described by a bilinearbiquadratic spin Hamiltonian. We modify the system with an externally controllable quadratic Zeeman effect, which yields a rich phase diagram. We generate the phase diagram and simulate the dynamics of QPT's using timeevolving block decimation  a matrix product state numerical method. Of particular interest are the finite size effects in the gapless to gapless transition that occurs in one dimension between the XY nematic phase and the Dimer nematic phase. From the entanglement entropy, we compute the critical exponents for the Isingtype transition from Ising nematic to Dimer nematic phases. We quench to criticality to observe pure KibbleZurek effects. [Preview Abstract] 

Q1.00037: The nonequilibrium behavior of spinor quantum gases Lauren Aycock, Srivatsan Chakram, Mukund Vengalattore We report on our progress towards understanding the equilibrium phases and nonequilibrium dynamics of spinor quantum gases. These fluids feature a rich phase diagram due to the interplay between superfluidity and magnetism, and the presence of long range dipolar interactions. We present a characterization of our multispecies spinor gas apparatus capable of generating large, spatially extended spinor condensates at high duty cycle. In addition, we complement our experimental efforts with theoretical studies of the thermalization and coarsening dynamics of quenched spinor gases. We propose methods for the controlled generation, detection and study of topological defects peculiar to these multicomponent quantum fluids. [Preview Abstract] 

Q1.00038: Nucleation of solitons in a quasi1D BoseEinstein condensate: the KibbleZurek mechanism Gor Nikoghosyan, Adolfo del Campo, Alex Retzker, Martin Plenio Finiterate cooling of a quasi1D thermal atomic cloud leads to the spontaneous nucleation of solitons during BoseEinstein condensation (BEC). We study whether the dynamics of the transition can be described in terms of equilibrium properties using the KibbleZurek mechanism (KZM), and simulate the process within the stochastic GrossPitaevskii equation. We propose a novel method to detect the density of solitons in a quasi1D BEC. This method is based on the measurement of the second order correlation function which enables the detection of solitons without knowing their location. The dependence of the density of solitons on the cooling rate of the atomic cloud for realistic experimental conditions is numerically analyzed, and agrees with the KZM only when this is extended to account for the inhomogeneous nature of the condensation arising from the external trapping potential. [Preview Abstract] 

Q1.00039: Singlet and triplet superfluids in a twocomponent Fermi  dipolar Bose mixture Ben Kain, Hong Ling We consider a mixture of a twocomponent Fermi and an (electric) dipolar Bose gas in a low temperature regime where the dipolar gas can be approximated with a condensate of dipolar bosons plus a collection of phonon modes which obey an anisotropic dispersion relation. The interaction between bosons and fermions induces an effective interaction between two fermions, which inherits the phonon mode anisotropy. We show that the anisotropy of such a FermiFermi interaction, in the long wavelength limit, strongly favors scattering of high order partial waves, which are otherwise suppressed in the usual FermiBose mixture. This, along with the ability to independently tune the dipolar interaction with an electric field and the swave scattering length between two fermions of opposite spins with a magnetic field, makes our proposed model an attractive alternative for the exploration of the physics of phase transitions or even phase coexistence between the singlet and triplet superfluids. We anticipate that the optimal critical temperature for triplet pairing can be realized in the mixed phase that separates from the BoseFermi mixture. [Preview Abstract] 

Q1.00040: Spinorbit coupling for $^{87}$Rb in the large coupling limit Abigail Perry, Ian Spielman We report on the construction of a new atomchip apparatus for the study of spinorbit coupling in $^{87}$Rb. Previous studies have successfully used Raman dressed spin state potentials to create an effective magnetic field [1]. The previous implementation used momentum transfer from two Raman laser beams to create a double well in momentum space, coupling spin states in the m$_{f }$= 1 and m$_{f}$ = 0 spin states. Instead, our new atomchip design utilizes ``Raman wires'' spaced 0.5$\mu $m apart in a temporally sequenced threephase configuration, with captured atoms located within 5$\mu $m from the chip surface. This configuration will produce fields that can couple different momentum states. Relative to previous experiments, our design will decrease spontaneous emission due to lack of laser beams, resulting in increased lifetimes. [1] Y.J. Lin et al., Nature, 462 628 (2009) [Preview Abstract] 

Q1.00041: Towards production of ultracold molecular ions in a hybrid trap system Scott Sullivan, Wade Rellergert, Kuang Chen, Steven Schowalter, Svetlana Kotochigova, Eric Hudson We describe a new method for the production of ultracold molecular ions. This method utilizes sympathetic cooling due to the strong collisions between appropriately chosen molecular ions and lasercooled neutral atoms to realize ultracold, internal groundstate molecular ions. In contrast to other experiments producing cold molecular ions, our proposed method efficiently cools both the internal and external molecular ion degrees of freedom. The availability of truly ultracold molecular ions will impact fields as diverse as quantum chemistry, precision measurement, and quantum information/computation. We report on direct evidence of ionneutral interactions observed in the system. [Preview Abstract] 

Q1.00042: Relativistic Vortices in BoseEinstein Condensates Laith Haddad, Lincoln Carr We present two different approaches to the formation of vortices for a BoseEinstein condensate in a honeycomb optical lattice. In the first approach, we consider vortices in the condensate order parameter. These are multicomponent localized solutions of the nonlinear Dirac equation with nontrivial rotation about a core phase singularity [1]. They are different from ordinary spinor vortices because the Berry phase induced by the lattice background supports a remarkable bosonfermion mapping in the quasiparticle operator statistics [2]. Another type of vortex occurs when we add a mass gap by including distortions of both the nearest neighbor and nextnearest neighbor hopping, as well as a staggered chemical potential between the two sublattices. Vortices with fractional statistics emerge when the superfluid order parameter is integrated over a topological defect in the mass gap.\\[0pt] [1] L. H. Haddad and L. D. Carr, ``The Nonlinear Dirac Equation in BoseEinstein Condensates: Foundation and Symmetries,'' Physica D: Nonlinear Phenomena, v. 238, p. 1413 (2009). http://arxiv.org/pdf/0803.3039v1 [2] L. H. Haddad and L. D. Carr, ``Relativistic Linear Stability Equations for the Nonlinear Dirac Equation in BoseEinstein Condensates,'' Submitted to Europhysics Letters Jan. 2011. http://arxiv.org/abs/1006.3893 [Preview Abstract] 

Q1.00043: Lattice Induced Resonances in One Dimensional Bosonic Systems Javier von Stecher, Victor Gurarie, Leo Radzihovsky, Ana Maria Rey Feshbach resonances and~optical lattices offer a unique opportunity for achieving new ways to control and explore novel manybody phenomena in strongly correlated atomic systems. To deal with such complex systems~a natural prerequisite is a full understanding of the underlying twobody physics. Here, we investigate the lattice induced resonances produced when dimers formed with atoms in excited bands become resonant with the atoms in the lowest band. We first obtain accurate twobody solutions and demonstrate that the resonant effects depend strongly on the parity properties of the dimer. Then, we develop a novel twochannel effective lattice Hamiltonian with a parity dependent atomdimer coupling that provides a starting point to analyze the manybody behavior of the resonant lattice system. We conclude that the lattice induced resonances significantly affect the behavior of the atoms in the lowest band and can be used to tune lattice systems to novel manybody regimes. [Preview Abstract] 

Q1.00044: A twodimensional fourbeam annular accordion optical lattice for ultracold atoms John Huckans, Ian Spielman In his seminal 1976 paper\footnote{D.R. Hofstadter, Phys. Rev. B 14, 2239 (1976).} ``Energy levels and wave functions of Bloch electrons in rational and irrational magnetic fields,'' Hofstadter suggested that his intriguing fractal spectrum be tested experimentally by creating a lattice with a larger period than Nature provides us. In his words: ``This is not to say that the idea is easy; but such an intriguing spectrum deserves a good experimental test.'' To measure this spectrum we developed a technique for creating artificial magnetic fields for neutral atoms, and now are constructing a widerange twodimensional accordion optical lattice\footnote{L. Fallani et al., Opt. Express 13, 43034313 (2005).}$^,$\footnote{T.C. Li et al., Opt. Express 16, 54655470 (2008).}$^,$\footnote{R.A. Williams et al., Opt. Express 16, 1697716983.} by steering four paraxial laser beams onto an atom cloud using a single large annular lens. In addition to eliminating spherical aberration, this novel design leaves the central solid angle surrounding the optical axis completely unobstructed for imaging and other purposes. [Preview Abstract] 

Q1.00045: Computational Investigation of Dipole Traps Formed by the Projection of Diffraction Patterns from a Circular Aperture Glen D. Gillen, Katharina GillenChristandl Previously we have shown that laser light incident upon a circular diffracting aperture produces intensity distributions suitable for either reddetuned (RDT) or bluedetuned (BDT) optical dipole traps for cold neutral atoms [1]. Typically, the calculated traps are located within a millimeter of the diffracting aperture, which requires the aperture to be located inside of the vacuum chamber. Using a combination of scalar diffraction theory and beam propagation techniques, a mathematical model has been developed to project the diffraction pattern away from the aperture [2]. Projected intensity distributions allow for the diffracting aperture and optics to be located outside of the vacuum chamber. We will present calculations which show that the properties of the RDT and BDT sites are not only maintained through the projection, but also can be manipulated using a simple singlelens optical system.\\[4pt] [1] Gillen, et al., PRA 73, 013409 (2006)\\[0pt] [2] GillenChristandl and Gillen, PRA 82, 063420 (2010). [Preview Abstract] 

Q1.00046: Ultracold atoms in optical lattices: beyond the Hubbard model Sebastiano Pilati, Ping Nang Ma, Xi Dai, Matthias Troyer We investigate the properties of strongly interacting gases in optical lattices. We address the regime of weak and intermediate optical potentials, where the conventional description in terms of the single (or few) band Hubbard model is not valid. In this interesting regime intriguing quantum phenomena appear due to the interplay between strong interatomic interactions and the external periodic potential. In the case of bosonic atoms, we introduce a novel pathintegral Monte Carlo technique which allows to simulate the superfluid to insulator transition in continuous space. For Fermions, we apply KohnSham Density Functional Theory (DFT) using a new energydensity functional for repulsive Fermi gases. The first results based on a local spin density approximation show evidence of a ferromagnetic phase due to repulsive interactions. As an outlook, we will discuss how the development of DFT for ultracold atomic gases can form a strong link between materials science and atomic physics. [Preview Abstract] 

Q1.00047: Dwave Superfluidity in a Cold Atomic Trap AnneLouise G. Larsen, H. Francis Song, Karyn Le Hur We have studied strongly repulsive fermions in a 2D optical lattice with harmonic confinement in the under doped regime. To study this we have taken the tJ model as our starting point and used the renormalized meanfield theory, where the projection to the singly occupied space is taken care of through the Gutzwiller factors. The Bogoliubovde Gennes equations have then been derived by diagonalization of the meanfield Hamiltonian. These have been solved, and the equations for the Fermi liquid order parameter, the pairing order parameter, and the doping concentration have been solved selfconsistently. Our results show that we are able to have a coexistence of phases in the trap if we choose the trapping frequency and the number of particles correct. This is manifested by a finite gap in the centre of the trap and a Fermi liquid at the boundaries at finite temperature. [Preview Abstract] 

Q1.00048: Numerically exact simulations of strongly interacting fermions in an optical lattice Michael Wall, Lincoln Carr We present large scale variational matrix product state (MPS) simulations of the FermiBose Hubbard model, which is an effective twochannel resonance model for a strongly interacting twocomponent Fermi gas in an optical lattice. The Hubbard parameters appearing in this model are determined from the exact solution of the twofermion problem including interband couplings and renormalization of the molecular energy in the closed channel.\footnote{H. P. B\"uchler, {\it Phys. Rev. Lett.} {\bf 104} 090402 (2010)} This approach allows us to quantitatively determine the phase diagram of alkali atoms interacting via a Feshbach resonance in a quasi1D geometry as a function of the experimental parameters. The applicability of this model to describe dynamics across a Feshbach resonance will also be discussed. [Preview Abstract] 

Q1.00049: Signatures of effective three and fourbody interactions and dynamics in collapseandrevival interferometry Philip Johnson, Eite Tiesinga When ultracold atoms are loaded into an optical lattice, the confinement of the atoms within the wells modifies their effective interaction properties and dynamics. For atoms in the lowest vibrational state, collisioninduced virtual excitations to excited states result in both renormalization of the twobody interactions, and effective three, four and higherbody interactions. The strength of the effective interactions depends in interesting ways on the lattice depth, dimensionality, and geometry. We show how this physics can be understood within an effective Hamiltonian approach that is particularly useful for understanding the nonlinear interferometry of collective states of atoms in lattices. We also show how the phase dynamics of collective states in the lattice can be surprisingly sensitive to fourbody interactions. [Preview Abstract] 

Q1.00050: ELECTRONIC, ATOMIC, MOLECULAR AND SURFACE INTERACTIONS 

Q1.00051: Trajectorydependent formation of hydrogen anions on reconstructed Si surfaces Boyan Obreshkov, Uwe Thumm We calculated the angular distributions of hydrogen anions that scatter off a (2x1) reconstructed Si (100) surface with an incident kinetic energy of 1 keV as a function of the direction of incidence. Depending on the scattering trajectory, we find anionformation probabilities between 0.1 and 10 per cent and show that negativeion formation is more likely for scattering trajectories that are aligned with rows of Si dimers while being unlikely for trajectories that are oriented perpendicularly the dimer bonds. After averaging over trajectories, our numerical results are in good quantitative agreement with the measured H fractions of M. Maazouz and V. Esaulov (Surf. Sci. 398, 49 (1998)). [Preview Abstract] 

Q1.00052: Tmatrix approach for fewbody problems in ultracold atomic gases Xiaoling Cui We propose a systematic Tmatrix approach to solve fewbody problems in a dilute atomic gas. The problem is generally reduced to a matrix equation expanded by a set of orthogonal molecular states, describing external centerofmass motions of pairs of interacting particles; while each matrix element is guaranteed to be finite by a proper renormalization for internal relative motions. This approach is able to incorporate various scattering issues in a single framework, including the bound state, effective scattering length and reduced interaction in lower dimension(s). Finally this method is applied to study three fermions in a (rotating) harmonic trap, where exotic scattering properties are uniquely identified and the results should shed light on quantum Hall physics in this system. [Preview Abstract] 

Q1.00053: Hydrogen recombination due to collision with noble gas atoms Stephen Paolini, Luke Ohlinger, Robert C. Forrey Quantum mechanical calculations are reported for hydrogen recombination in the presence of a chemically inert spectator. The calculations employ a square integrable Sturmian basis set to provide a discrete representation of the H$_2$ continuum. Direct threebody recombination is approximated by computing transitions from the nonresonant continuum. Resonant and nonresonant states are handled on equal footing within the sequential twostep energy transfer mechanism. Theoretical rate coefficients are computed within the equilibrium and steadystate approximations for the density of intermediate molecules. The results are compared with existing experimental data for He and Ar. The sensitivity of the calculations to pressure variations and to changes in the potential energy surface are investigated for He. The reliability of these calculations and their relevance for astrophysical models is discussed. [Preview Abstract] 

Q1.00054: Collisional Frequency Shifts in a Fermionic Yb Lattice Clock Nathan Lemke, Andrew Ludlow, Jeff Sherman, Chris Oates, Javier Von Stecher, Ana Maria Rey In optical lattice clocks based on fermionic isotopes of Sr and Yb, densitydependent frequency shifts are among the leading contributors to the total clock uncertainty. These shifts are caused by swave collisions which arise from optical excitation inhomogeneity, allowing otherwise identical fermions to collide. Here we study the collisions in $^{171}$Yb with Ramsey spectroscopy for 1 and 2dimensional lattice confinement. In particular, we show how details of the spectroscopy (e.g. pulse area, dark time) affect the collision shifts and, in some cases, can be used to zero the resulting shift. [Preview Abstract] 

Q1.00055: Molecular $^{85}$Rb$_2$ Formation in a 1D 10.6 $\mu$m Optical Lattice R. Carollo, H.K. Pechkis, D. Rahmlow, M. Bellos, J. Banerjee, E.E. Eyker, P.L. Gould, W.C. Stwalley We present results on the formation of ultracold $^{85}$Rb$_2$ molecules in an optical lattice formed by a simple retroreflected CO$_2$ laser. Atoms are loaded to the lattice from an ordinary MOT at a temperature of $\sim$20 $\mu$K after a transient cooling stage. They are then illuminated by a photoassociation laser from a singlemode Ti:Sapphire to briefly form excitedstate molecules that decay to the singlet ground state. Utilizing resonanceenhanced twophoton ionization, we detect these molecules and measure their decay lifetimes. Stateselective detection allows us to monitor the population of individual vibrational levels to measure collisional relaxation rates separately. This work is supported by the NSF and AFOSR. [Preview Abstract] 

Q1.00056: Doppler Broadening induced by fast heavy particles in molecular hydrogen Zoran Petrovic, Vladimir Stojanovic, Zeljka Nikitovic We study anisotropy of anomalously broadened Halpha line in a low current Townsend discharge in hydrogen. Monte Carlo simulation based on the best available collision data was used to predict kinetic energies of excited atoms including their angular distribution which results in the anisotropy of the broadened wings. Monte Carlo simulations included elastic, inelastic, and reactive collisions of electrons, energetic hydrogen ions, atoms and molecules [A.V. Phelps, Phys. Rev. E\textbf{ 79}, 066401 (2009)]. We obtained the Halpha profiles with far wings mainly both in direction of the field (end on) and as observed at 90$^{o}$ to the field (side on). In order to observe the effect of heavy particles we subtract the electron induced contribution to the profiles. Very large degree of anisotropy exists in the far wings. The ``end on'' profiles due to the fast neutrals are quite asymmetric. ``Side'' on profiles are symmetric with a large central peak due to all the fast particles aligned with the electric field, and the broad wings due to scattered fast neutrals gaining some perpendicular momentum. The wide wing component grows rapidly towards the cathode. [Preview Abstract] 

Q1.00057: The density broadening in a condensate detected by a pulse train Jianing Han High resolution microwave spectroscopy has been used to detect the density broadening in a Bose Einstein Condensate (BEC) by probing the Sodium clocktransition. Rabi line shape is generated by a single pulse and Ramsey fringes are produced by two pulses. Here we measured the density broadening by multiple pulses. Moreover, by narrowing the pulsewidth of the pulses, the collisional broadening can be partially reduced. Furthermore, this multipulse technique can be calculated by exactly solving the timedependent twolevel Schrodinger equations. And the experimental results are compared with the calculations. [Preview Abstract] 

Q1.00058: Cold Metastable NH molecules Maya Fabrikant, Travis Briles, Noah Fitch, Heather Lewandowski We report progress towards producing samples of cold trapped NH molecules using a stark decelerator. The NH molecule has a metastable state (a1Delta) approximately 1.5 eV above the ground state and a lifetime of several seconds. We create of a beam of cold NH molecules almost entirely in the a1 delta state by supersonic expansion and in situ photolysis of HNCO. We determine the rotational and translation temperatures of the beam using 2+1 resonance enhanced multiphoton ionization spectroscopy. The NH molecules are then slowed in a stark decelerator and trapped using static electric fields. Once the molecules are trapped, we will overlap a magnetic trap of ultracold rubidium atoms to study nearresonant quenching of metastable NH. [Preview Abstract] 

Q1.00059: Rubidium $5P$ finestructure mixing due to threebody collisions in dense $^{4}$He gas Jerry Sell, Robert Lloyd, Jonathan Plyler, Brian Patterson, Randy Knize, Alina Gearba We will report on the enhancement of Rb finestructure transfer in helium buffer gas due to threebody collisions which occur at dense ($\geq$ 1 atm) He pressures. Previously we measured the threebody finestructure transfer rate for a room temperature RbHe mixture. Additional measurements have been made to examine the temperature dependence of this effect. The finestructure transfer rates are measured by detecting the emitted fluorescence from collisional excitation transfer using timecorrelated singlephoton counting, with the fluorescence curves fitted to the solutions of the rate equations for a threelevel atomic system. The RbHe mixture is varied in temperature from 25200 C and the $^{4}$He pressure is varied from 503000 Torr. [Preview Abstract] 

Q1.00060: Threebody recombination in He + H + H Nicolais L. Guevara, W. Blake Laing, Brett D. Esry Considerable progress has been made recently in the calculation of threebody recombination rates. Most of this effort, however, has focused on ultracold collisions, although a recent calculation has obtained a recombination rate at temperatures as high as 0.5 K [1]. We present our progress on a new method to calculate the threebody recombination rate to much higher energies using realistic potentials. This method diabatizes the adiabatic hyperspherical representation using physical arguments. We will illustrate the method for the astrophysicallyrelevant reaction He + H + H $\rightarrow$ H$_2$ + He. We hope this method enables tractable calculations at astrophysicallyrelevant temperatures as well. \\[4pt] [1] Y. Wang, J.P. D'Incao, B.D. Esry, arXiv:1012.0680 (2010) [Preview Abstract] 

Q1.00061: Theoretical Studies of Dissociative Recombination of Electrons with N$_2$H$^+$ Ions R.F. Malenda, D.O. Kashinski, D. Talbi, F. Gatti, A.P. Hickman We are investigating the dissociative recombination (DR) of electrons with the molecular ion $\mathrm{N}_2\mathrm{H}^+$. (The process is $e^ + \mathrm{N}_2\mathrm{H}^+ \rightarrow \mathrm{N}_2 + \mathrm{H}$.) $\mathrm{N}_2\mathrm{H}^+$ is found in the interstellar medium, and a better understanding of the DR process will aid the development of astrophysical models. We have performed large scale electronic structure calculations of several excitedstate diabatic potential surfaces of $\mathrm{N}_2\mathrm{H}$ involved in DR. Additional calculations used the multiconfiguration timedependent Hartree (MCTDH) method to propagate quantum mechanical wave packets on the potential surfaces involved in the direct DR process. For these calculations, $\mathrm{R_{NN}}$ is fixed at its equilibrium value, and the angular dependance in the Jacobi coordinate system is fit with a Legendre polynomial expansion. The cross section for the direct method has been found to be small for low energies. Rydberg potentials are being calculated for use in investigation of the indirect method. The current status of the work will be reported at the conference. [Preview Abstract] 

Q1.00062: Formation of negative molecular ions $M$H$^$ in the interstellar medium by radiative association of a molecule $M$ and an H$^$ ion M. Ayouz, O. Dulieu, M. Raoult, S. Galtier, I. Mikhailov, V. Kokoouline We consider if negative molecular ions of the type $M$H$^$ can be formed in the interstellar medium by radiative association of the negative hydrogen ion H$^$ (RAH$^$) to a molecule $M$. For this goal, we consider the CO and H$_2$O molecules, which are abundant in the ISM, as candidates for $M$. We have determined {\it ab initio} potential energy surfaces and dipole moments for COH$^$ and H$_3$O$^$ ions. The two molecular ions are bound. We will present a preliminary estimation of the rate coefficients of RAH$^$ to H$_2$O and CO. We have also determined rotational constants of COH$^$ and H$_3$O$^$ ions that allows us to construct theoretical IR spectra for these ions. Previously, we have found that IR absorption frequencies for H$_3^$ are out of range of the orbital telescopes, but the IR absorption spectra for COH$^$, and H$_3$O$^$ are within the range of wavelengths of Herschel telescope, which could be used to detect such ions. An eventual observation of $M$H$^$ would indicate that the H$^$ ion is also present in the interstellar medium. [Preview Abstract] 

Q1.00063: Vortices in CoulombBorn calculations for innershell ionization of carbon by electronimpact S.J. Ward, J.H. Macek The deep minimum in the He(e,2e)He$^+$ measured TDCS [1] have been traced to vortices in the continuum wave function [2]. Using the CoulombBorn approximation [3], we show that vortices are also present in innershell ionization of carbon by electron impact. We considered the energy of the incident electron to be $E_i$ = 1801.2 eV and the scattering angle to be $\theta_f = 4^\circ$. We located a vortex when the momentum of the electron ${\bf k}$ is (0.547,0,0.326), where the zaxis is taken along the incident momentum ${\bf K}_i$ and the xaxis is in the plane of the incident and scattered electrons. At this ${\bf k}$, both $\Re$[Tmatrix] and $\Im$[Tmatrix] are zero. The integral of the velocity field around a closed loop encircling the zero of the Tmatrix is $2 \pi$ as is required for a vortex. We also located vortices for outofplane geometries ($k_y$ nonzero) for $\theta_f = 4^\circ$ and also inplane for different scattering angles. Obtaining vortices in the CoulombBorn approximation is important since they effect the electron momentum distribution and the approximation gives for {\it fixed scattering angles} the highenergy limit for electronimpact innershell ionization. [1] A.~J.~Murray and F.~H.~Read, PRA {\bf 47}, 3724 (1993). [2] J.~H.~Macek et. al, PRL {\bf 104}, 033201 (2010). [3] J.~Botero and J.~H.~Macek, PRA {\bf 45}, 154 (1992). [Preview Abstract] 

Q1.00064: Elastic scattering of slow electrons from Mn, Zn and Cd atoms: First prediction of stable negative ions Z. Felfli, A.Z. Msezane, D. Sokolovski The appearance of a large peak in low energy electron  atom elastic scattering total cross sections (TCSs) facilitates considerably the identification of the binding energies (BEs) of negative ions, formed during the collision as resonances [1]. Both relativistic and nonrelativistic calculations [2, 3] and coupled cluster and multireference methods[3] concluded that Mn, Zn and Cd atoms do not bind electrons to form stable negative ions. Crucial to the existence and stability of most negative ions are the electron correlations and corepolarization interactions. The recent Reggepole methodology [4] wherein these physical effects are embedded is used to explore possible formation of stable negative ions of Mn, Zn and Cd through slow electron collisions. From the imaginary parts of the complex angular momenta, we conclude that all these atoms form stable weakly bound negative ions. Binding energies, shape resonances and RamsauerTownsend minima are presented. \\[4pt] [1] P. D. Burrow \textit{et al}, J. Phys. B \textbf{9}, 3225 (1976) \\[0pt] [2] Z. J. Wu \textit{et al}, Chem. Phys. Lett. \textbf{423}, 81 (2006) \\[0pt] [3] N. B. Balabanov~ \textit{et al}, J. Chem. Phys. \textbf{123}, 064107 (2005); \textbf{125}, 074110 (2006) \\[0pt] [4] D. Sokolovski \textit{et al}, Phys. Rev. A \textbf{76}, 012705 (2007) [Preview Abstract] 

Q1.00065: Multiple excited negative ion formation in low energy electron collisions with Tm, Lu and Hf atoms Z. Felfli, A.Z. Msezane, D. Sokolovski The interplay between negative ion resonances and RamsauerTownsend minima that characterize low energy electron elastic total cross sections (TCSs) has been identified as the fundamental mechanism that drives nanoscale catalysis [1]. Accurate binding energies (BEs) are required for understanding chemical reactions involving negative ions. Thus, there is need to identify and delineate resonance structures and minima in electron TCSs for atoms and molecules in the near threshold energy region. Here we explore, following the recent success [2], lowenergy E $\le $ 1.0 eV electron elastic scattering from Tm, Lu and Hf complex atoms, searching for electron attachment manifesting as Regge resonances in the TCSs, using our recent Regge pole method [3]. Sharp resonances characterize these cross sections, corresponding to the multiple negative ion formation. From the energy positions of the resonances we have extracted the BEs of the ground, first and second excited states of the Tm\={ }, Lu\={ } and Hf\={ }. Our BEs for Hf\={ } are compared with existing data. \\[4pt] [1] A.Z. Msezane \textit{et al}, J. Phys. B \textbf{43}, 201001 (2010) \\[0pt] [2] Felfli\textsc{ }\textit{et al}, Phys. Rev. A \textbf{81}, 042707 (2010). \\[0pt] [3] D. Sokolovski \textit{et al}, Phys. Rev. A \textbf{76}, 012705 (2007) [Preview Abstract] 

Q1.00066: Elastic cross sections for Mn, Ni, Cu, Zn, Ag and Cd atoms by low energy electrons A.Z. Msezane, Z. Felfli, D. Sokolovski There is a great need for a fundamental understanding of the mechanism of the nearthreshold electron attachment to the atoms Mn, Ni, Cu, Zn, Ag and Cd, particularly the identification and characterization of the attendant resonance structures in the electron elastic total cross sections (TCSs). The crucial electronelectron correlations and corepolarization interactions, vital to the existence and stability of most negative ions, render understanding the structure and the dynamics of lowenergy electron elastic collisions resulting in the formation of negative ions as resonances, quite challenging for conventional theoretical methods. Here we have investigated using the successful complex angular momentum (CAM) method [1,2] the TCSs for Mn, Ni, Cu, Zn, Ag and Cd in the energy range 0 $\le $ E $\le $ 1 eV to identify and delineate the resonance structures and minima. The imaginary part of the CAM is used to distinguish between the stable bound states of the negative ions (longlived resonances) and the shape resonances (shortlived resonances). TCSs, RamsauerTownsend minima, shape resonances and BEs are presented. \\[4pt] [1] D. Sokolovski \textit{et al}, Phys. Rev. A \textbf{76}, 012705 (2007).\\[0pt] [2] Felfli\textsc{ }\textit{et al}, Phys. Rev. A \textbf{81}, 042707 (2010) [Preview Abstract] 

Q1.00067: Low energy electron scattering from atoms: Search for nanocatalysts A.Z. Msezane, Z. Felfli, D. Sokolovski Manipulating the structure and the dynamics of metallic nanoparticles, attractive due to their optical, electronic and magnetic properties, including applications in catalysis, requires a fundamental understanding of the dynamic processes at the atomic level. The fundamental mechanism of catalysis at the atomic scale has already been proposed and demonstrated in Au, Pd and AuPd catalysis of H$_{2}$O$_{2}$ through the scrutiny of low energy electron elastic total cross sections (TCSs) [1]. The use of mixed precious metal catalysts can produce even higher activities compared to Au alone [2]. Here the interplay between negative ion resonances and RamsauerTownsend minima that characterize low energy electron TCSs for Au is identified as the fundamental signature of nanoscale catalysts. Calculated electron elastic TCSs for Ag, Pt, Pd, Ru and Y atoms are presented as illustrations. The recent complex angular momentum methodology is used for the calculations [3]. It is concluded that these atoms are suitable candidates for nanocatalysts individually or in combinations. \\[4pt] [1] A.Z. Msezane \textit{et al}, J. Phys. B \textbf{43}, 201001 (2010); EurophysicsNews \textbf{6}, 11 (2010) \\[0pt] [2] D.T. Thompson, Nano Today\textbf{ 2}, 40 (2007) \\[0pt] [3] D. Sokolovski \textit{et al}, Phys. Rev. A \textbf{76}, 012705 (2007) [Preview Abstract] 

Q1.00068: Bspline Rmatrix with pseudostates calculation for electronimpact ionization of helium Oleg Zatsarinny, Klaus Bartschat We have extended the Bspline Rmatrix (BSR) method [1] to include a large number of pseudostates. These pseudostates are not only important for the accurate treatment of electronimpact excitation processes at intermediate energies, but they also allow for the calculation of ionization processes, using the same basic ideas as in the convergent closecoupling and standard Rmatrix with pseudostates (RMPS) approaches [2,3]. The generality and flexibility of our BSRMPS extension makes it possible to use multiple cores of the residual He$^+$ ion as well as specially optimized shortrange correlation orbitals to achieve an accurate description of the initial bound state, the important part of the singleelectron excitation spectrum, autoionizing states, and finally the ionization and ionizationexcitation continua. We obtain excellent agreement with the most recent experimental data [4,5]. [1] O. Zatsarinny, Comp. Phys. Commun. {\bf 174} (2006) 273. [2] D. V. Fursa and I. Bray, Phys. Rev. A {\bf 52} (1995) 1279. [3] K. Bartschat and I. Bray, J. Phys. B {\bf 29} (1996) L577. [4] R. Rejoub, B. G. Lindsay, and R. F. Stebbings, Phys. Rev. A {\bf 65} (2002) 042713. [5] A. A. Sorokin, I. L. Beigman, S. V. Bobashev, M. Richter, and L. A. Vainshtein, J. Phys. B {\bf 37} (2004) 3215. [Preview Abstract] 

Q1.00069: Cross Sections for Electron Scattering from Singly Ionized Nitrogen Swaraj Tayal The improved atomic calculations for electron impact excitation cross sections for the astrophysically important lines in N II are reported. The collision calculations have been performed in the closecoupling approximation using the Bspline BreitPauli Rmatrix method. The flexible nonorthogonal sets of spectroscopic and correlation orbitals are employed for an accurate representation of the target states and scattering functions. The closecoupling expansion included 58 bound levels of the $2s^22p^2$, $2s2p^3$, $2s^22p3s$, $2s^22p3p$, $2s^22p3d$, $2s^22p4s$, $2s^22p4p$, and $2s2p^23s$ configurations. The relativistic effects have been included through mass, Darwin, and spinorbit operators in the BreitPauli Hamiltonian. The calculated excitation energies are in excellent agreement with experiment. The present results of cross sections are compared with available other closecoupling calculations. [Preview Abstract] 

Q1.00070: Detecting Electron Motion in Atoms and Molecules HuaChieh Shao, Anthony Starace Ultrafast electron pulses have been proposed to observe timedependent phenomena in atoms and molecules [1]. Detection of spatial and temporal electronic motion by scattering of subfs pulses of 10 keV electrons from coherent superpositions of electronic states of both H and T$_2^+$ is investigated [2]. In such pump/probe calculations for the H atom, we predict measurable changes of the diffraction images that reflect the timedependent effective radius of the electronic charge density. For an aligned T$_2^+$ molecule, we predict diffraction image changes that reflect the timedependent localization (delocalization) of the electronic charge density about one (two) of the nuclei.\\[4pt] [1] P.~Baum and A.H.~Zewail, Proc.~Natl.~Acad.~Sci.~U.S.A.~\textbf{104}, 18409 (2007); S.A.~Hilbert, C.~Ulterwaal, B.~Barwick, H.~Batelaan, and A.H.~Zewail, Proc.~Natl.~Acad.~Sci.~U.S.A.~\textbf{106}, 10558 (2009).\\[0pt] [2] H.C. Shao and A.F.~Starace, Phys.~Rev.~Lett.~\textbf{105}, 263201 (2010). [Preview Abstract] 

Q1.00071: Ionization and Recombination Measurements at the Heidelberg Heavy Ion Storage Ring TSR D.W. Savin, M. Hahn, M. Lestinsky, O. Novonty, D. Bernhardt, A. Mueller, S. Schippers, C. Krantz, A. Wolf Reliable ionization balance calculations are needed to analyze spectra from a wide range of cosmic sources including photoionized objects such as AGNs and Xray binaries and electron ionized objects such as as stars, supernovae, galaxies, and clusters of galaxies. These theoretical charge state distributions (CSD) depend in turn upon the underlying atomic data. Of particular importance are reliable rate coefficients for dielectronic recombination (DR), which is the dominant electronion recombination recombination mechanism for most ions, and for electron impact ionization (EII). We are carrying out DR and EII measurements of astrophysically important ions using the heavy ion Test Storage Ring (TSR) at the MaxPlankInstitute for Nuclear Physics in Heidelberg, Germany. The storage ring measurements are largely free of the metastable contamination found in other experimental geometries. Storage ring measurements therefore result in more precise DR and EII reaction rate measurements. The measured rate coefficients can be used in modeling cosmic and laboratory plasmas as well as in the benchmarking of theoretical atomic calculations. Here we report results for selected recent DR and EII measurements. [Preview Abstract] 

Q1.00072: Electron Impact Excitation Collision Strengths for FineStructure Transitions in Si VIII Swaraj Tayal Electron impact excitation collision strengths for transitions between the finestructure levels of the $2s^22p^3$, $2s2p^4$, $2p^5$, $2s^22p^23s$, $2s^22p^23p$, and $2s^22p^23d$ configurations in Si VIII have been calculated using the B spline BreitPauli Rmatrix method. The distinctive feature of the atomic calculations is the use of Bsplines as a universal basis to represent the scattering functions. The multiconfiguration HartreeFock method with termdependent non orthogonal orbitals is employed for an accurate representation of the target wave functions. The calculated excitation energies are in excellent agreement with the experimental energies, and represent significant improvements over the previous calculations. The closecoupling expansion included 76 bound levels in the scattering calculation. The present results have been compared with available other calculations. The oscillator strengths and collision strengths for several transitions will be presented. [Preview Abstract] 

Q1.00073: InnerShell Ionization of Atoms (Z=6 to 92) by electron Bidhan Saha The electron impact ionization (EII) is of fundamental importance in understanding the physics of the collision process involving manyelectron. Accurate EII cross sections (EIICS) are essential in many fields, ranging from astrophysics to molecular physics, to plasma physics for different targets over a wide range of energies. Four easy to handle models, such as the MBELL, XCVTS, GKLV and MUIBED [1], are used to evaluate EIICS. A few selected targets are considered to report their predictions and compared them with experimental EIICS data and other theoretical findings at the conference. \\[4pt] [1] A. K. F. Haque, M. A. Uddin, M. Shahjahan, M. R.Talukder, A. K. Basak, B. C. Saha, in \textit{Advances in Quantum Chemistry}, Vol \textbf{61}, 2011 (in press). [Preview Abstract] 

Q1.00074: Electron scattering from krypton: Highresolution electron scattering experiments and Bspline Rmatrix calculations Oleg Zatsarinny, Klaus Bartschat, Michael Allan In a joint experimental and theoretical effort, we carried out a detailed study of elastic scattering and electron impact excitation of the $\rm 4p^5 5s$ states in Kr. We present independently normalized, absolute angledifferential cross sections over the entire angular range ($0^\circ  180^\circ$) for a number of energies in the nearthreshold region, as well as energy scans for selected angles. Interesting double minima were observed in the elastic cross section as a function of energy for backward angles. The present experimental results are in very satisfactory agreement with predictions from a fully relativistic Dirac \hbox{$B$spline}\hbox{$R$matrix} model~[1,2]. They clearly improve the agreement between experiment and theory relative to our earlier comparison [2] with the data of Phillips [3]. \\[4pt] [1] O. Zatsarinny and K. Bartschat, Phys. Rev. A {\bf 77} (2008) 062701.\\[0pt] [2] T. H. Hoffmann, M.W. Ruf, H. Hotop, O. Zatsarinny, K. Bartschat, and M. Allan, J. Phys. B {\bf 43} (2010) 085206.\\[0pt] [3] J. M. Phillips, J. Phys. B {\bf 15} (1982) 4259. [Preview Abstract] 

Q1.00075: Electron Impact Ionization of Helium Atom Hari P. Saha We plan to report the results of our calculation on electron impact ionization of helium atom for symmetric and asymmetric configuration using the Multiconfiguration HartreeFock (MCHF) method for electron impact ionization of atoms [1,2]. Our main emphasis will be focused on the calculation of final state wave function more accurately at low excess energies. We will present results of our calculation for triple differential cross sections at few low excess energies. The calculated results will be compared with other available theoretical and experimental data. Finally we will discuss on the quality of the final state wave function accounting for electron correlation between the two final state continuum electrons. \\[4pt] [1] Hari P. Saha, Phys. Rev. A 77, 062705 (2008)\\[0pt] [2] Hari P. Saha, Phys. Rev. A 82, 042703 (2010) [Preview Abstract] 

Q1.00076: Triple differential cross sections for the electronimpact ionization of He and H$_2$ James Colgan, Michael Pindzola We present calculations of the triple differential cross sections arising from the electronimpact ionization of He and H$_2$. The timedependent closecoupling approach is used to calculate the cross sections for the single ionization process, resulting in various geometric and kinematic final states. In particular, we examine the triple differential cross sections for He at an incident electron energy of 71 eV, for equal ($E_1=E_2=23$ eV) and unequal ($E_2=3, 10$ eV) energy sharing. We discuss the convergence properties of these cross sections and compare our results to available measurements. For the electronimpact ionization of H$_2$, we present triple differential cross sections for ionization of molecules at specific orientations (with respect to the incoming electron beam). We study the cross section as a function of energy sharing between the outgoing electrons, as well as for two different internuclear separations of the H$_2$ molecule. Orientation effects, as well as differences between the angular distributions from He and from H$_2$, will be explored. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DEAC5206NA25396. [Preview Abstract] 

Q1.00077: Understanding Plasma Optical Emission Diagnostics using Ar Excitation Cross Sections John B. Boffard, R.O. Jung, Chun C. Lin, Amy Wendt Electronatom collisions are the primary excitation mechanism of lowtemperature plasmas. Nevertheless, the emissions of most lines are the result of many excitation channels: direct excitation from the ground state, excitation into higher levels that radiatively cascade into the level of interest, and excitation from longlived metastable atoms in the plasma. Incorporating these processes into a radiative model, we have used Ar emissions to determine the electron energy distribution functions of inductively coupled plasmas[1]. Emissions from the Ar($3p_5$) and Ar($3p_9$) levels, at 419.8~nm and 420.1~nm respectively, are found to exhibit a particularly interesting intensity ratio that is very sensitive to plasma conditions. The 420.1/419.8 line ratio varies from $\sim 1$ at high electron temperatures ($T_e$), to $\sim 3$ at low $T_e$. These variations can be explained in terms of the nearly equal ground state optical emission cross sections, and the vastly different cross sections out of the metastable levels[2]. We explore the atomic physics that drives this particular line ratio and how it can be used to noninvasively measure the electron temperature of argon containing plasmas. \\[4pt] [1] Plasma Sources Sci. Technol. \textbf{19}, 065001 (2010);\\[0pt] [2] Phys. Rev. A \textbf{75}, 052707 (2007). [Preview Abstract] 

Q1.00078: Transition probabilities and collision strengths for electronimpact excitation of Cl$^{2+}$ A.M. Sossah, S.S. Tayal We report on transition probabilities and effective collision strengths for electronimpart excitation of the astrophysically important Cl$^{2+}$ ions. The collision strengths are calculated in the closecoupling approximation using the Bspline BreitPauli Rmatrix method. The multiconfiguration HartreeFock method with termdependant nonorthogonal orbitals is employed for an accurate description of the target wave functions. The 70 finestructure levels belonging to the 33 \textit{LS} states of 3s$^{2}$3$p^{3}$, 3$s$3$p^{4}$, 3$s^{2}$3$p^{2}$3$d$, 3$s^{2}$3$p^{2}$4$s$ and 3$s^{2}$3$p^{2}$4$p$ configurations are included in the closecoupling approximation; this leads to 2415 possible finestructure transitions. The effective collision strengths are obtained by averaging the electron collision strengths over a Maxwellian distribution of velocities, and these are tabulated for all finestructure transitions at electron temperatures in the range 5,000 to 100,000 K. Our results are compared with previous theoretical results and available experimental data. This work is supported by NASA grant NNG09AB63G from the Planetary Atmospheres Program. [Preview Abstract] 

Q1.00079: Reaction dynamics in double ionization of helium by electron impact M. Ciappina, M. Schulz, T. Kirchner We present theoretical fully differential cross sections for double ionization of helium by 500 eV and 2 keV electron impact [1]. Contributions from various reaction mechanisms are calculated separately and compared to experimental data. Our theoretical methods are based on the first Born approximation. Higherorder effects are incorporated using the Monte Carlo Event Generator technique. Earlier, we have successfully applied this approach to double ionization by ion impact and in the work reported here it is extended to electron impact. We demonstrate that at 500 eV impact energy double ionization is dominated by higherorder mechanisms. Even at 2 keV double ionization does not predominantly proceed through a pure firstorder process. \\[4pt] [1] M. F. Ciappina et al., Phys. Rev. A 82, 062701 (2010) [Preview Abstract] 

Q1.00080: Electron Impact Excitation of S III Claire Hudson, Cathy Ramsbottom We present collision strengths and effective collision strengths for the electron impact excitation of S\,{\sc iii}. The paralell RMATRX II suite of codes have been used, which perform the calculation in intermediate coupling, and we have incorporated 29 $LS$ states in our calculation, which gives rise to 53 fine structure levels and a total of 1378 transitions. Collision strengths have been generated over an electron energy range of 012\,Ryd, and from these effective collision strength data are determined for electron temperatures in the range log$_{10}$T(K)=3.06.0. Results are given for transitions between the the fine structure levels within the ground state configuration of 3s$^2$3p$^2$. Comparisons are made with the previous $R$matrix calculations of Galav\'{i}s, Mendoza \& Zeippen [1] (carried out as part of the IRON Project) and that of Tayal \& Gupta [2]. Our current work helps to resolve a large discrepancy which existed between the these two earlier calculations for some of the data within the ground state transitions.\\[4pt] 1] Galav\'{i}s ME, Mendoza C, \& Zeippen CJ 1995, Astron. Astrophys. Suppl. Ser. 111 347;\\[0pt] [2] Tayal SS \& Gupta GP 1999 ApJ 526 544. [Preview Abstract] 

Q1.00081: Laser assisted electronargon scattering at small angles Nathan Morrison, Chris H. Greene We investigate the scattering of electrons off of neutral argon in the presence of a linearly polarized, low frequency laser field. Of particular interest is the cross section of electrons scattered at small angles to the field direction, where the Kroll Watson approximation becomes less accurate. We represent the electron wavefunction as a sum over angular momentum and Floquet channels, and use the eigenchannel R matrix method to solve the Schr\"odinger equation at small distances in the length gauge. The argon atom is represented in this calculation by a model potential including a screened coulomb term near the origin and a longer range induced dipole interaction. The R matrix is then transformed into the short range reaction matrix in the KramersHenneberger (acceleration) representation using spherical GordonVolkov states, and from this the cross section is derived. Experiments have shown the cross section at small angles to be much higher than the approximation for electrons that absorb or emit photons, and we hope to gain insight into this phenomenon with this method. [Preview Abstract] 

Q1.00082: O($^{1}$D) production following electron impact on oxygencontaining molecules William McConkey, Wladek Kedzierski, Elly Blejdea, Amanda DiCarlo, Jeffrey Hein O($^{1}$D) is an important species in the earth's atmosphere giving rise to the well known oxygen red lines at wavelengths of 630.0 and 636.4 nm from the upper atmosphere and strongly influencing stratospheric photochemistry. O($^{1}$D) is metastable and is difficult to detect selectively in the laboratory. We have developed techniques and instrumentation involving a solid Ne matrix at 10K that is sensitive to this species through the formation of excited excimers (NeO*) which immediately radiate. Relative cross sections as a function of impact electron energy will be presented for N$_{2}$O and CO$_{2}$ targets. Threshold energy data will be used to gain information about the parent molecular states. [Preview Abstract] 

Q1.00083: New Apparatus for the Study of ElectronInduced Molecular Dissociation Dynamics Ali Moradmand, Joshua Williams, Devin Kalafut, Allen Landers, Mike Fogle A new COLTRIMStype momentum imaging apparatus, consisting of a skimmed gas jet crossed with a pulsed electron beam, is used to study electroninduced dissociation dynamics. The apparatus makes use of a synchronously pulsed electrostatic spectrometer coupled with a positionsensitive detector. This spectrometer provides both timeofflight and initial momentum information for ion fragments formed during dissociation. Energydependent results for single and double ionization of methane will be presented as well as dependence on molecular orientation. Future projects involving anioncation fragment pair production and lowenergy dissociative electron attachment to molecules will also be discussed. [Preview Abstract] 

Q1.00084: Electron impact dissociative ionization of nitrosyl chloride Pengqian Wang The study of the dissociation dynamics of molecular ions provides valuable information on the electronic states and the potential energy surfaces of molecules. Electron impact is a widely used method to excite and ionize molecules. In this presentation we report our experiment on electron impact dissociative ionization of nitrosyl chloride (NOCl), studied at an electron beam kinetic energy of 200 eV. The dissociation channels of up to triply ionized NOCl are investigated by two and threedimensional covariance mapping methods. The absolute cross sections for the different dissociation channels are measured. The major ionic fragments from the dissociation of singly charged nitrosyl chloride are NO$^{+}$, N$^{+}$ and O$^{+}$. No considerable parent ions of NOCl have been observed. The NOCl dications dissociate mainly into ion pairs, among which the major abundant channels are N$^{+}$+O$^{+}$ and NO$^{+}$+C1$^{+}$. The NOCl trications dissociate into both ion pairs and ion triples. The experimental cross sections are compared with ab initio calculation on the energies of molecular orbitals. Project supported by the WIUURC grant. [Preview Abstract] 

Q1.00085: Theoretical and Experimental Triple Differential Cross Sections for Electron Impact Ionization of Methane Haari Ch, Shenyue Xu, Chuangang Ning, Don Madison, Xueguang Ren, Thomas Pflueger, Arne Senftleben, Alexander Dorn, Joachim Ullrich Triple differential cross sections have been calculated and measured for 54 eV electronimpact ionization of the highest occupied molecular orbital (HOMO) 1t2 state of methane (CH4). Results will be presented both for the scattering plane and a plane in which the ejected electron is perpendicular to the incident beam direction. A systematic comparison between theoretical DWBA (distorted wave Born approximation), M3DW (molecular 3body distorted wave), and experiment will be given for ejected electron energies ranging between 5 eV to 20 eV and scattered projectile angles ranging between 20 degrees and 55 degrees. In the perpendicular plane, better qualitative agreement between experiment and theory was found for the smaller projectile scattering angles and higher ejected electron energies. In the scattering plane on the other hand, agreement between theory and experiment tended to be better for the lower ejected electron energies. [Preview Abstract] 

Q1.00086: Positronium and electron scattering on Helium Joseph Di Rienzi, Richard Drachman A recent work [1] establishes experimentally that Positronium scattering by atoms of various elements is surprisingly close in total crosssection to that of an isolated electron of the same velocity. In this work we will look at the scattering of Ps on Helium and compare it to a determination of the scattering of an e with the same element. For both the Ps scattering and the e scattering on He, we assume the symmetrization of the e with the closed shell He electrons is the dominant interaction. A local effective potential employed in [2] and [3] is used to model the electron exchange and cross sections are determined for a set of partial waves. For the Ps scattering we include as a secondary effect the Van der Waals interaction. For single e scattering of He, we also employ a short range Coulomb potential and dispersion as contributing effects. Results of the crosssections determined in each case are then compared. \\[4pt] [1] S. J. Bromley, S. Armitage, J. Beale, D. E. Leslie, A. I. Williams, G. Laricchia, Science 330, 789 (2010)\\[0pt] [2] R. J. Drachman, S.K. Houston, J. Phys. B: At. Mol. Phys. 3 1657 (1970)\\[0pt] [3] J. Di Rienzi, R. J. Drachman, J. Phys. B. 36 2409 (2003) [Preview Abstract] 

Q1.00087: Ionization and excitation in collisions between antiprotons and H($1s$) atoms Thomas Winter Coupledstate cross sections have been determined for ionization and excitation to states up to H($3d$) in collisions between 1 keV to 16 MeV antiprotons and H($1s$) atoms\footnote {T. G. Winter, Phys. Rev. A (in press).} using the same twocenter, as well as onecenter, Sturmian bases as for proton projectiles.\footnote{T. G. Winter, Phys. Rev. A {\bf 80}, 032701 (2009).} A detailed comparison and strong contrast at lower energies is made with results for equienergy proton projectiles, while at high energies all cross sections are tied explicitly to the firstBorn limit to better than 1\%. The use of a doublecenter basis for antiproton projectiles, in spite of there being no capture channels, was first suggested and carried out by Toshima with a large Gaussian basis\footnote {N. Toshima, Phys. Rev. A {\bf 64}, 024701 (2001).}; it provides both additional variational freedom and allowance for antiprotoncentered effects, including chargecloud depletion. Results will be compared with recent theoretical results\footnote{M. McGovern, D. Assafr\~{a}o, J. R. Mohallem, C. T. Whelan, and H. R. J. Walters, Phys. Rev. A {\bf 79}, 042707 (2009).} and earlier results, including experimental ionization cross sections.\footnote{H. Knudsen, U. Mikkelsen, K. Paludan, K. Kirsebom, S. P. M{\o}ller, E. Uggerh{\o}j, J. Slevin, M. Charlton, and E. Morenzoni, Phys. Rev. Lett. {\bf74}, 4627 (1995).} [Preview Abstract] 

Q1.00088: Lowenergy Swave PositroniumHydrogen Collisions D. Woods, S.J. Ward, P. Van Reeth In response to proposed measurements discussed by St.~Olaf's positron group of lowenergy positroniumalkali atom scattering [1], we begun a theoretical investigation of Ps scattering. Recently, we computed singlet and triplet Swave phase shifts for lowenergy elastic PsH scattering process. This process is of interest since it is a fundamental fourbody Coulomb process. We employed the Kohn variational method and a number of variants on the method, namely, the inverse Kohn, generalized Kohn, and the complex Kohn for the Smatrix and Tmatrix. We compare our results to the earlier Kohn and inverse Kohn calculations [2,3]. \\[4pt] [1] Jason Engbrecht, {\it Private Communication}.\\[0pt] [2] P.~Van Reeth and J.~W.~Humberston, J.~Phys.~B {\bf 36}, 1923 (2003).\\[0pt] [3] P.~Van Reeth and J.~W.~Humberston, Nucl.~Instrum.~Methods Phys.~Res. A {\bf 221},140 (2004). [Preview Abstract] 

Q1.00089: Hyperspherical hidden crossing calculation of Ps formation in lowenergy e$^+$Na collisions S.J. Ward, J. Shertzer The hyperspherical hidden crossing method (HHCM) can provide important insight into scattering processes. Previously, we have used the HHCM to calculate the Ps(1s)formation cross section in lowenergy e$^+$H [1] and e$^+$Li [2] collisions. Here we apply the HHCM to lowenergy e$^+$Na collisions. We use the Peach model potential and treat e$^+$e$^$Na$^+$ as an effective threebody system. We calculate the Ps(1s)formation cross sections for $0 \le L \le 3$ and compare our results with a hyperspherical closecoupling calculation [3]. The HHCM provides an explanation for the small Swave Ps(1s)formation cross section. The Swave St\"uckelberg phase is close to $\pi$ for the three collision systems due to destructive interference between the two amplitudes that correspond to different paths leading to Ps(1s) formation. \\[4pt] [1] S.~J.~Ward, J.~H.~Macek, and S.~Yu.~Ovchinnikov, Phys.~Rev.~A {\bf 59}, 4418 (1999); S.~J.~Ward and J.~Shertzer (unpublished).\\[0pt] [2] S.~J.~Ward and J.~Shertzer, Phys.~Rev.~A {\bf 68}, 032720 (2003); {\bf 75}, 012713 (2007).\\[0pt] [3] AnhThu Le, M.~W.~J.~Bromley and C.~D.~Lin, Phys.~Rev.~A {\bf 71}, 032714 (2005); AnhThu Le (private communication). [Preview Abstract] 

Q1.00090: Positron Scattering from the Noble Gases C. Makochekanwa, J. Machacek, A. Jones, P. Caradonna, R. McEachran, J. Sullivan, S. Buckman Studies of low energy (0.5  60 eV), high resolution (60 meV), positron scattering from atoms have been carried out at the Australian National University. A series of measurements of positron scattering from noble gas targets has been made as part of a program to establish benchmark cross section values for positron scattering. Here we present some recent measurements of positron scattering from the rare gas atoms, including benchmark total scattering, positronium formation and elastic differential cross sections, and measurements of Wigner cusps in the elastic channel at the Ps threshold. We will present examples of trends observed in a number of these scattering processes in He, Ne, Ar, Kr and Xe. Comparison of the present results with the best available theoretical calculations, and other experimental data from the literature will also be made. [Preview Abstract] 

Q1.00091: Toward a better understanding of resonant annihilation on molecules C.M. Surko, J.R. Danielson, A.C.L. Jones For many if not most molecules, annihilation at positron energies $\epsilon$ in the range of the vibrational modes proceeds via vibrational Feshbach resonances (VFR) in which positrons attach to these targets.\footnote{Gribakin and Lee, Phys. Rev. Lett. {\bf 97}, 193201 (2006).}$^,$\footnote{Gribakin, Young, and Surko, Rev. Mod. Phys. {\bf 82}, 2557 (2010).} In small molecules, the theory of Gribakin and Lee provides a quantitative description of the annihilation rates, $Z_{\rm eff}$. However other effects are currently less well understood. Described here are some open questions and experiments using deuterium substitution that are designed to address them. They include the effect of intramolecular vibrational energy redistribution (IVR) on $Z_{\rm eff}$ in large molecules (e.g., alkanes), the role of molecular rotations on VFR in very small molecules (e.g., ammonia), and the observation of combination and overtone modes in molecules of small to intermediate size (e.g., acetylene and ethylene). [Preview Abstract] 

Q1.00092: Chemical trends in positron binding to acetates, formates, aldehydes and ketones. A.C.L. Jones, J.R. Danielson, C.M. Surko Positron annihilation on molecules as a function of incident positron energy exhibits vibrational Feshbach resonances (VFR).\footnote{Gribakin, Young, and Surko, Rev. Mod. Phys. {\bf 82}, 2557 (2010).} The energy shifts between the vibrational modes and the VFR provide a measure of the positronmolecule binding energy, $\epsilon_b$. Measurements of $\epsilon_b$ for over 40 molecules have now been made. A previous analysis expressed the dependence of $\epsilon_b$ on molecular parameters as $\epsilon_b \approx 12.4(\alpha + 1.6\mu  5.6)$ [meV], where $\alpha$ is the molecular polarizability and $\mu$ is the permanent dipole moment.\footnote{Danielson, Young, and Surko, J.~Phys.~B {\bf 42}, 235203 (2009).} Measurements for molecules with large $\mu$ show enhancements beyond the predictions using the formula.\footnote{Danielson, Gosselin, and Surko, Phys.~Rev.~Lett., {\bf 104}, 233201 (2010).} New measurements on acetates, formates, aldehydes, and ketones, will be presented. An analysis of these chemical trends will be discussed that illustrates the importance of molecule geometry and the location of $\mu$ and the methyl groups in influencing the size of $\epsilon_b$. [Preview Abstract] 

Q1.00093: Positron Interactions with Biologically Relevant Molecules P. Palihawadana, J.R. Machacek, E. Anderson, C. Makochekanwa, J.P. Sullivan, G. Garcia, M.J. Brunger, S.J. Buckman A series of measurements of positron interactions with biologically relevant molecules have been undertaken. We present both total scattering and differential scattering cross sections for Uracil (C$_{4}$H$_{4}$N$_{2}$O$_{2})$, Tetrahydrofuran or THF (C$_{4}$H$_{8}$O), 3hydroxyTHF (C$_{4}$H$_{8}$O$_{2})$ and Pyrimidine (C$_{4}$H$_{4}$N$_{2})$. These measurements are absolute and include the positronium formation cross section which is important to investigations of positron transport in biological systems. The energy of the magnetically confined positron beam can be tuned between 1 and 200 eV, and the energy resolution of the beam is between 60 and 100 meV. We will discuss the experimental techniques, the sources of systematic errors which limit the current results, and prospects for the future. [Preview Abstract] 

Q1.00094: Modelling Positron Interactions with Matter G. Garcia, Z. Petrovic, R. White, S. Buckman In this work we link fundamental measurements of positron interactions with biomolecules, with the development of computer codes for positron transport and track structure calculations. We model positron transport in a medium from a knowledge of the fundamental scattering cross section for the atoms and molecules comprising the medium, combined with a transport analysis based on statistical mechanics and MonteCarlo techniques. The accurate knowledge of the scattering is most important at low energies, a few tens of electron volts or less. The ultimate goal of this work is to do this in soft condensed matter, with a view to ultimately developing a dosimetry model for Positron Emission Tomography (PET). The highenergy positrons first emitted by a radionuclide in PET may well be described by standard formulas for energy loss of charged particles in matter, but it is incorrect to extrapolate these formulas to low energies. Likewise, using electron crosssections to model positron transport at these low energies has been shown to be in serious error due to the effects of positronium formation. [Preview Abstract] 

Q1.00095: The influence of anisotropic scattering of positrons on transport coefficients Ana Bankovic, Sasa Dujko, Zoran Petrovic, Stephen Buckman, Ronald White Positron Emission Tomography is widely used technique for general diagnostics of metabolic activity and for the identification of cancerous tumors. The fundamental interactions of positrons with atoms and molecules in the human body are not well understood and quantified. Modeling of damage induced by positrons traversing the living tissue (usually modeled as water) is not an easy task and almost every existing model in medicine is based on semi empirical data. In this work, positron transport is investigated in water vapour using isotropic and anisotropic scattering models, based on fundamental collisional data obtained in either beam experiments or by theoretical calculations. The latter model is particularly important since the water molecule is highly polar. Benchmark calculations are performed using a Monte Carlo simulation technique. Similar very strong effects of positronium formation are observed as in argon. Several transport coefficients has been determined for a wide range of E/N which may be used as a benchmark for testing of codes aimed at modeling of positron diagnostics and therapy. [Preview Abstract] 

Q1.00096: Near Resonant Charge Transfer in IntermediateHigh Energy Collisions between Molecular Ions and Atomic Hydrogen V.M. Andrianarijaona, D.G. Seely, I.N. Draganic, C.C. Havener Using the Oak Ridge National Laboratory (ORNL) ionatom mergedbeams apparatus, absolute cross sections of near resonant direct and dissociative charge transfer (CT) between H/D and different molecular ions (D$_{2}^{+}$, CO$^{+}$, O$_{2}^{+}$, and D$_{3}^{+})$ are measured from 20eV/u to 2keV/u collision energies. Below a few hundred eV/u collision energy, each measured cross section exhibits the dynamics of the vibrational and rotational modes of the molecular ion. Toward high energy collisions where the differences in the Qvalue of the reaction can be neglected and the rovibrational modes can be considered as frozen, the measured CT cross sections for the diatomic ions increase, lose track of the rovibrational mode signatures and all converge to (7.5 $\pm $ 0.5) x 10$^{16}$ cm$^{2}$ at 2keV/u. The measured CT cross section for the triatomic ion D$_{3}^{+}$, which may have only endoergic dissociative CT channels, differs from that of the diatomic ions. [Preview Abstract] 

Q1.00097: High Energy Measurement of the Associative Detachment Reaction H$^{}$ + H $\rightarrow$ H$_{2}$ + e$^{}$ Using a MergedBeams Apparatus Kenneth A. Miller, Hjalmar Bruhns, Holger Kreckel, Daniel Wolf Savin, Martin Cizek, Xavier Urbain Using a merged beams apparatus we have measured the associative detachment reaction of H$^$~+~H~$\rightarrow$~H$_{2}~+~e^{}$ for relative collision energies \textit{E}$_{\rm{r}}$~$\leq$~4.8~eV. These data extend above the 1~eV limit of our previous results. We have also investigated and ruled out several possible sources of systematic error in our previous work. Merging both data sets these results are in excellent agreement with recent theoretical calculations and confirm the prediction that this reaction essentially turns off for $E_{\rm r}$~$\ge$~2.25~eV. Similar behavior has been predicted for protonium formation from collisions of antiprotons with hydrogen atoms. [Preview Abstract] 

Q1.00098: Status of Charge Exchange Cross Section Measurements for Highly Charged Ions on Atomic Hydrogen I.N. Draganic, C.C. Havener, D.R. Schultz, D.G. Seely, P.C. Schultz Total cross sections of charge exchange (CX) for C$^{5+}$, N$^{6+}$, and O$^{7+}$ ions on ground state atomic hydrogen are measured in an extended collision energy range of 1  20,000 eV/u. Absolute CX measurements are performed using an improved mergedbeams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source mounted on a high voltage platform. In order to improve the problematic H$^{+}$ signal collection for these exoergic CX collisions at low relative energies, a new double focusing electrostatic analyzer was installed. Experimental CX data are in good agreement with all previous Hoven relative measurements at higher collision energies. We compare our results with the most recent molecular orbital close coupling (MOCC) and atomic orbital closecoupling (AOCC) theoretical calculations. [Preview Abstract] 

Q1.00099: A novel merged beam apparatus to study the cosmic origins of organic chemistry Aodh P. O'Connor, Mauricio Garrido, Kenneth A. Miller, Daniel W. Savin, Xavier Urbain We are constructing a novel mergedbeams apparatus to study the cosmic origins of organic chemistry. With this, we plan to measure reactions of atomic C with molecular ions. Rate coefficients for such reactions are a critical component of the astrochemical models used to predict interstellar molecular abundances and to analyze spectroscopic observations of moleculebearing cosmic sources. Initial studies will focus on $\mathrm{C + H^+_3 \rightarrow CH^+ + H_2}$ reactions, an important first step in leading to interstellar organic chemistry. Starting with a $\mathrm{C^}$ beam, we will use laser photodetachment to generate a C beam; the residual $\mathrm{C^}$ will then be removed leaving a pure neutral beam. Subsequently an $\mathrm{H^+_3}$ beam will be merged with the C beam. Since the beams will be copropagating, we will be able to study reactions down to collision energies of the order of ten meV ($\leq 140$ K). Reactions will be studied using an electrostatic analyzer to separate and detect the charged end products, allowing us to determine absolute reaction cross sections. [Preview Abstract] 

Q1.00100: Differential cross sections for single ionization of H2 by 75keV proton impact Uttam Chowdhury, Michael Schulz, Don Madison We have calculated Triply differential cross sections (TDCS) and doubly differential cross sections (DDCS) for single ionization of by 75 KeV proton impact using the molecular 3 body distorted wave Eikonal initial state (M3DWEIS) approach. Previously published measured DDCS (differential in the projectile scattering angle and integrated over the ejected electron angles) found pronounced structures at relatively large angles which were interpreted as an interference resulting from the twocentered potential of the molecule. Theory treating H2 as atomic H multiplied by a molecular interference factor only predict the observed structure when assumptions are made about the molecular orientation. Here we apply the M3DWEIS method, which does not rely on such an ad hoc approach, but rather treats the interference from first principles and we find the same structure without assuming any preferential orientations. [Preview Abstract] 

Q1.00101: Origin of ringlike structures in the distribution of fast electrons in slow collisions of He$^{2+}$ with He S.Y. Ovchinnikov, J.S. Sternberg, D.R. Schultz, J.H. Macek Fully correlated, 4dimensional lattice calculations of the electron spectra for transfer ionization in slow collisions of He$^{2+}$ with He reveal ringlike structures in the distribution of fast electrons. The structures are manifestations of the interference of two channels of direct ionization occurring during the incoming portion of the collision. In the evolution of the initial electronic state, the diabatic$_{ }^{1}\Sigma ^{+}_{g}$(2p$\sigma ^{2})$ term crosses the $^{1}\Sigma ^{+}_{g}$(1s$\sigma $3d$\sigma )$ term and twoelectron transitions at this crossing define the two channels for direct ionization . In the dominant channel, S$_{d\sigma }$promotion occurs via twoelectron transitions from the initial adiabatic $^{1}\Sigma ^{+}_{g}$(2p$\sigma ^{2})$ state to the $^{1}\Sigma ^{+}_{g}$(1s$\sigma $3d$\sigma )$ state and then to the continuum. In the subdominant channel, the S$_{p\sigma }$promotion occurs from the initial adiabatic $^{1}\Sigma ^{+}_{g}$(2p$\sigma ^{2})$ state directly to the continuum. The difference in phases for the evolution of the system along the 1s$\sigma $ and 2p$\sigma $ potential curves during of the outgoing part of the collision produces the ringlike structures in the transfer ionization channel. [Preview Abstract] 

Q1.00102: The influence of the micromotion on the sympathetic cooling of an ion immersed in an ultracold gas Michal Krych, Zbigniew Idziaszek We investigate the influence of ion micromotion in a Paul trap on the sympathetic cooling of an ion immersed in an ultracold gas or a BoseEinstein Condensate. The motivation for our investigation are recent experiments on hybrid ultracold atomion systems. In order to trap an ultracold ion a timedependent trap is needed. Apart from the main effective harmonic frequency (secular motion) also the so called ``micromotion'' appears. Its influence on the sympathetic cooling by the ultracold gas has not been calculated nor understood properly yet. Previous experiments performed with hot gases show that the ion can be sympathetically cooled or heated by the gas  depending on the atomion mass ratio and interaction strength. Our analytical calculations show that a similar behavior will be present in an ultracold gas. [Preview Abstract] 

Q1.00103: Mshell xray production cross sections from 75300 keV proton impact on Hf, Re, and Au Sam Cipolla M xray spectra from 75300 keV proton bombardment of thick elemental targets of Hf, Re, and Au were measured using a ultrathin window Si(Li) detector. Spectral analysis yielded xray production cross sections of the major xray transitions M$_{\alpha }$, M$_{\beta }$, M$_{\gamma }$, M$_{2}$N$_{4}$, M$_{1}$O$_{3}$ representative of vacancy filling of the five M subshells. Results are compared with predictions from nonrelativistic ECPSSR and relativistic RPWBABC theories. [Preview Abstract] 

Q1.00104: Charge Exchange in O$^{7+}$+H collisions J.L. Nolte, Y. Wu, P.C. Stancil, R.J. Buenker, D.R. Schultz, Y. Hui, I.N. Draganic, C.C. Havener Charge exchange between heavy solar wind ions and interstellar neutrals is thought to be a dominant contributor to the heliospheric component of the soft xray background, as the highly charged resultant ion emits an xray photon through the electron's cascade to the ground state. In this study we calculate $n$, $l$, $S $resolved charge capture cross sections into the dominant $n=4$, 5 and 6 manifolds for the system O$^{7+}$+H, over a range of collision energies 0.0150 keV/u, using the molecular orbital close coupling method. We compare our results with classical trajectory Monte Carlo, atomic orbital close coupling, and experimental results. [Preview Abstract] 

Q1.00105: Charge exchange and chemical reactions with trapped thorium ions Michael DePalatis, Layne Churchill, Michael Chapman Most atomic nuclei have excitation energies ranging from keV to MeV. A unique exception is the $^{229}$Th nucleus, which has an excited state just several eV above the nuclear ground state.\footnote{B.~R.~Beck \textit{et al.}, \textit{Phys. Rev. Lett.} \textbf{98}, 142501 (2007).} Th$^{3+}$ provides a convenient level structure for laser cooling in an rf Paul trap.\footnote{C.~J.~Campbell \textit{et al.}, \textit{Phys. Rev. Lett} \textbf{102}, 233004 (2009).} Unlike many ions commonly utilized in precision measurements, the trap lifetime of Th$^{3+}$ is limited to only several minutes. This is a severe limitation to experiments involving $^{229}$Th as it is only available in minute quantities. Here we have studied the loss mechanisms by introduction of various contaminants and analyzed reaction products using trapped ion mass spectrometry techniques.\footnote{L.~R.~Churchill \textit{et al.}, \textit{Phys. Rev. A} \textbf{83}, 012710 (2011).} [Preview Abstract] 

Q1.00106: Hyperfine interactions and charge transfer processes in ultracold atomion collisions Diego Valente, Robin C\^ot\'e In some atomion scattering systems, the hyperfine interaction may be neglected, e.g. if the nuclear spins of both atom and ion are null, or if the hyperfine coupling constant is very small. In other systems, this is not the case. Collisions between Be and Be$^{+}$ provide access to both types, depending on the nuclear spin of the Be isotope considered. We investigate the role of hyperfine interactions by considering collisions between Be atomion isotopes with zero nuclear spin (e.g. $^{8}$Be or $^{10}$Be), and $^{7}$Be (with a nuclear spin of 3/2). For identical nuclei, symmetry considerations must be taken into account in computing charge transfer cross sections. Precise calculations of these are presented, which could be valuable for several ultracold trapped ion applications and quantum computing experiments. [Preview Abstract] 

Q1.00107: Investigation of Isotope Effects in Single Ion Reactions James Goeders, Craig Clark, Ncamiso Khanyile, Kenneth Brown Cold molecular ions are of great interest for studying chemical reactions. At the ultralow temperatures achievable using laser cooling techniques, chemical reactions are dominated by quantum effects not generally observed at higher temperatures. Studying reactions at these low temperatures allows for probing of the reaction mechanisms and the topology of potential energy surfaces, providing tests of \textit{ab initio} and reactive scattering calculations. Many chemical reactions are dominated by isotope effects. Ion beam studies have looked at reactions of alkaline earth ions with HD and observed different patterns of reactivity between Period 2 and Period 3 elements. Magnesium was shown to have a larger reaction crosssection for forming MgD$^{+}$ than MgH$^{+}$ by a factor of 2  4. Single ion experiments involving reactions between Mg$^{+}$ in the 3p$^{2}$P$_{3/2}$ excited state and HD, utilizing trapped atomic ions, were done by Staanum \textit{et al.}, showing a branching ratio on the order of the results seen in the beam studies. Ion beam experiments have also been done on groundstate $^{40}$Ca$^{+}$ with HD. In those experiments, the ratio of formation of CaH$^{+}$ to CaD$^{+}$ was observed to be $\sim$4, opposite and in stark contrast to the magnesium ratio. The current work compares single atomic calcium ion data with molecular beam data, looking at both the 4p$^{2}$P$_{3/2}$ and the 4p$^{2}$P$_{1/2}$ excited states, similar to the work done with Mg$^{+}$. [Preview Abstract] 

Q1.00108: Probing Surface Patch Fields with Rydberg Atoms Yu Pu, Dean Neufeld, Barry Dunning The stray electric patch fields present at a Au(111) surface are investigated by studying the ionization of Rydberg atoms incident at neargrazing angles. Measurements of the threshold conditions for observation of the resulting ions are used to estimate the size, and other characteristics, of the stray fields. This is accomplished using an iterative procedure and calculating the threshold conditions for different assumed field parameters using a simple overthebarrier model of surface tunneling. Excellent fits to the experimental data are obtained over a broad range of $n$ and angles of incidence and indicate that the stray fields can be as large as $\sim $10$^{3}$ V/cm 100nm from the surface decreasing to $\sim $ 20V/cm 500 nm from the surface. The use of lithographicallypatterned electrode arrays to further study the effects of stray fields is being explored. Simulations suggest that engineered electrode structures, which can generate localized fields approaching 10$^{4}$ V/cm, will help evaluate the potential of Rydberg atoms as a tool to detect and characterize stray fields as well as allow the detection of low$n (n \sim $ 10) Rydberg atoms. [Preview Abstract] 

Q1.00109: On the role of iontrajectories on confinement and recapture effects in the survival of anions scattered from metal surfaces Andrew Schmitz, John Shaw, Himadri Chakraborty Resonant charge transfer in ionsurface collisions is a classic tool to explore surface electronic structures. Using the CrankNicholson propagation [1] we solve the timedependent Schroedinger equation to simulate the electronic motion during collisions of H$^{ }$with Li(110) and Pd(111) surfaces. It was previously shown that the ion's survival after the collision depends (i) adiabatically (that is at slow ionspeeds normal to the surface) on electrons' confinement in metal band gap and (ii) diabatically on recaptures from image states [2]. We now find that for larger distances of closest approach (DCA) of the ion the image interaction accesses the adiabatic region and dominates the bandgap effect. In a real collision, the flighttrajectory determines the DCA as the metallattice repels the ion, resulting in a reduction in ion speed. Hence the trajectory induces a competition between various effects that is found to significantly modify the ionsurvival phenomenology.\\[4pt] [1] Chakraborty et al., \textit{Phys. Rev.} A \textbf{70}, 052903 (2004);\\[0pt] [2] Schmitz et al., \textit{Phys. Rev.} A \textbf{81}, 042901 (2010). [Preview Abstract] 

Q1.00110: Interactions of hydrogen anions with facecenteredcubic metal surfaces of (110) symmetry Jason Sauerbrei, Peter Sable, Hee Suk Lee, Andy Schmitz, Himadri Chakraborty Resonant charge transfer in ionsurface collisions determines the survival probability of the ion. The time evolution of the ion's initial electron density provides a microscopic account of the excitation of participating bulk states. We simulate this interaction by solving the timedependent Schroedinger equation for the H$^{}$ ion in front of various fcc metal surfaces of (110) symmetry in the same methodology used before for (111) and (100) surfaces [1,2]. The band structures of fcc (110) metals are very unique: The band gap in these metals is formed by the projection of the bulk states along the direction which does not intersect with the bulk Brillouin zone center, allowing for the localization of \textit{two} surface states inside the gap. Using a description of (110) surface [3] our study uncovers important effects of the (110) symmetry on the electrons' motion in general and on the resulting ion survival in particular.\\[4pt] [1] Chakraborty et al., \textit{Phys. Rev.} A \textbf{70}, 052903 (2004);\\[0pt] [2] Schmitz et al., \textit{Phys. Rev.} A \textbf{81}, 042901 (2010);\\[0pt] [3] Tsirkin et al., \textit{Surf. Sc.} \textbf{604}, 804 (2010). [Preview Abstract] 

Q1.00111: Sticking coefficients of Molecular Hydrogen on Amorphous Ice using Molecular Dynamics Simulations Vijay Veeraghattam, Steven Lewis, Phillip Stancil, Junko Takahashi The Molecular Dynamics (MD) method was employed to model hydrogen molecules interacting on the surface of amorphous ice and the sticking coefficients of H$_2$ were calculated. Interstellar dust grains are mostly composed of carbon or silicate grains with layers of amorphous ice on their surface. Interaction of molecular hydrogen with these grain surfaces is of astrophysical importance as the gasgrain interactions play a pivotal role in the chemical evolution of the universe. Our model implements the various dynamical processes that occur during the interaction of the H$_2$ molecules on the amorphous ice surface, including the random angle striking of H$_2$ on the surface, scattering of H$_2$, and sticking of H$_2$ to the surface. The temperature of the dust grains (T$_D$) and H$_2$ molecules (T$_{H_2}$) play an important role in the surface interactions and in the sticking process. We studied the sticking coefficients as a function of temperature distribution of T$_D$ and T$_{H_2}$. [Preview Abstract] 

Q1.00112: Quantum dynamics of H$_2$H$_2$ collisions Balakrishnan Naduvalath, Samantha Fonseca dos Santos, Stephen Lepp, Goulven Qu\'em\'ener, Robert C. Forrey, Phillip Stancil The H$_2$H$_2$ system has long been considered as a benchmark candidate for quantum dynamics studies of moleculemolecule collisions. H$_2$ is the most abundant molecular species in the interstellar medium and rotational and vibrational transitions in collisions between H$_2$ molecules have been topics of considerable interest. Here, we present a full quantum mechanical treatment of collisions between orthoortho, parapara, and orthopara H$_2$ molecules as well as the HDH$_2$ system over a wide range of energies and for different initial rovibrational levels of the molecules. The computed rate constants are compared against available experimental data and previous theoretical results. [Preview Abstract] 

Q1.00113: The loss and dephasing of the excited state Sodium condensate Jianing Han Two ways of characterizing the excited state condensate, the lifetime and rabi oscillations, are applied to study the excited state condensate: F=2 condensate. One of the F=2 condensates, $2,2>$, $2,1>$ and $2,0>$, is created by directly driving the F=1 state in an all optical BEC by a microwave pulse. The difference in the aspect ratio of expanding condensates, released from the F=1 and F=2 states, has been observed. This difference is due to the different scattering lengths in these two states. The fast decay of the the F=2 signal indicates a coherent process followed by a collision process. In addition, we have studied the density dephasing of this system by the Rabi oscillations, and we have shown that $t_0$, the damping time constant, depends linearly on the atomic density in the density range that we have studied. In addition, we have studied the density dephasing of this system by the Rabi oscillations, and we have shown that $t_0$, the damping time constant, depends linearly on the atomic density in the density range that we have studied. [Preview Abstract] 

Q1.00114: Circular Rydberg states of atomic hydrogen in an arbitrary magnetic field L.B. Zhao, B.C. Saha, M.L. Du A theoretical method using a Bspline basis set has been proposed to evaluate circular Rydberg states of atomic hydrogen in a strong magnetic field. The combination of this method and a recently reported finitebasisset technique [1] can provide a practicable scheme to implement high accuracy computations of circular Rydberg states of atomic hydrogen in an arbitrary magnetic field. Energy levels of hydrogen are presented for circular Rydberg states with azimuthal quantum numbers $\vert $m$\vert $ = 10  70 as a function of magnetic field strengths ranging from zero to 2.35 x 10$^{9}$ T. Comparison with available theoretical data shows excellent agreement. The variation of spatial distributions of electron probability densities with magnetic field strengths is discussed and competition between Coulomb and magnetic interactions is illustrated. \\[4pt] [1] J. Phys. B\textbf{40}, 4347 (2007) [Preview Abstract] 

Q1.00115: QUANTUM OPTICS, MATTER OPTICS, AND COHERENT CONTROL 

Q1.00116: Cross section of nonrelativistic Bremsstrahlung radiation in a dispersive and absorbing medium Marzieh Zare, Javad Usefie Mafahim Starting from the quantized version of Maxwell's equations for the electromagnetic field in an arbitrary permeable and linear KramersKronig dielectric, Bremsstrahlung radiation is studied in a dispersive and absorbing medium. Introducing the new interaction Hamiltonian, different from the one in the free space, the cross section for Bremsstrahlung radiation and indeed the probability of the interaction between a projectile particle, like an electron, and a nucleus is calculated using Fermi's golden rule. To investigate the difference between the scattering crosssection in the presence of a dispersive and absorbing medium and the one in free space, we defined a quantity that is the ratio of the scattering crosssection in this medium to the crosssection in free space. This ratio was computationally analyzed in the positive and the negative refractive index medium and since there are dielectric and permeability functions, two resonance frequencies are observed. Far from the resonance frequencies, this limit approaches to one. In general, for this interaction cross section we can trust the cross section in free space except around the resonance frequencies of the medium. [Preview Abstract] 

Q1.00117: Multiple beam interference in spiral phase plates Yisa Rumala, Aaron Leanhardt Optical transmission through a spiral phase plate is analyzed by treating the device as a FabryPerot etalon with an azimuthallyvarying thickness. The transmitted beam is calculated to contain a coherent superposition of optical vortices with different winding numbers. This yields an intensity profile with a periodic modulation as a function of azimuthal angle, which is verified experimentally. Applications in atom optics and matter wave interferometry will be discussed. [Preview Abstract] 

Q1.00118: Coherent Enhanced Absorption in an Intracavity Atomic Medium David D. Smith, Krishna Myneni, Hongrok Chang, Jamiu A. Odutola The conditions for coherent enhanced absorption of an intracavity atomic medium are discussed. For a symmetric cavity, a specific amplitude and phase relationship between two oppositely oriented input beams results in coherent perfect absorption by the medium [1]. In contrast, for a single input beam, perfect absorption requires a perfectly asymmetric, i.e., single port, cavity. Even when the cavity is not perfectly asymmetric or lossless, we find that enhanced absorption can occur. For a single input to an asymmetric cavity, as the input intensity is increased and the medium saturates, the cavity passes from the overcoupled to the undercoupled regime. We find the counterintuitive result that the cavity absorptance can increase with increasing input intensity in the overcoupled regime, i.e., the atomcavity system behaves as a reverse saturable absorber. These results were compared with measurements performed using a tunable laser incident on a FabryPerot cavity containing an Rb87 cell, taking into account the effects of saturation and beam divergence. \\[4pt] [1] Y. D. Chong, L. Ge, H. Cao, and A. D. Stone, Physical Review Letters 105, 053901 (2010). [Preview Abstract] 

Q1.00119: Observation of the spontaneously generated coherence effects in a laserdriven fourlevel system Jianbing Qi We study the spontaneously generated coherence effects in a fourlevel system coupled by three coherent fields. We use the Schr\"{o}dinger equation to calculate the probability amplitudes of the wave function of the system and derive an analytical expression of the spontaneous emission spectrum. A variety of spontaneous emission spectral features can be obtained by controlling the amplitude of the coupling fields and the preparation of the initial quantum state of the system. Quantum interference effects, such as the spectral line enhancement, spectrum splitting, and quenching are observed. The number of spectral components, the spectral linewidth, and relative intensity can be very different depending on the physical parameters. The system can be realized in many atomic and molecular systems. [Preview Abstract] 

Q1.00120: Temporal Response of a Plasmonic Antenna M. Becker, C.W. Huang, R. Bach, H. Batelaan, E. Smythe, F. Capasso Using femtosecond lasers, we investigate the temporal response of a plasmonic antenna [1]. This structure is fabricated by Capasso's group. In this report, we propose an application of such a plasmonic antenna:\textbf{ femtosecond electron switching}. The plasmonic antenna may be very effective in influencing the motion of free electrons because the intensity of an input electric field can be enhanced by up to a factor of a thousand in the near field [2]. Our estimates indicate that the plasmonic antenna can cause large deflection angles of about 0.1 radian upon applying a 10 nJ, 10 femtosecond duration laser pulse. Therefore, a low power, high repetition rate femtosecond laser may be used to excite the plasmonic structure and influence electrons' motion at the femtosecond time scale, leading to a femtosecond electron switch. We want to experimentally determine this dynamical response of the antenna. A preliminary test of the plasmonic antenna shows that it can respond in the femtosecond regime. Detection schemes that are sensitive to about 10 femtoseconds are now being explored. [1] Elizabeth J. Smythe, Ertugrul Cubukcu, and Federico Capasso, \textit{Opt. Exp.} \textbf{15}, 7439 (2007) [2] Ertugrul Cubukcu, et \textit{al.}, \textit{IEEE J. Sel. Top. Qu. Elec.}, Vol.14, No.6, 1448 (2008) [Preview Abstract] 

Q1.00121: Nanowire Plasmon Resonators Nathalie de Leon, Brendan Shields, Chun Yu, Dirk Englund, Alexey Akimov, Mikhail Lukin, Hongkun Park Strong interactions between light and matter can be engineered by confining light to a small volume for an extended period of time. Nanoscale plasmonic structures can concentrate lighte well below the diffraction limit, but realization of small modevolume plasmon cavities remains an outstanding challenge. We propose and demonstrate a new approach for realization of nanoscale plasmon resonators enabling strong lightmatter interaction. In our approach, chemically synthesized silver nanowires are surrounded by patterned dielectric to create resonators with mode volumes that are two orders of magnitude below the diffraction limit and quality factors approaching 100. We show that they can be used to enhance spontaneous emission rates of CdSe quantum dots and single diamond nitrogenvacancy centers by a factor larger than 20 at the cavity resonance. [Preview Abstract] 

Q1.00122: Theory and Testing of a Harmonic Trap for Atom Interferometry Matthew Squires, James Stickney, John Burke, Evan Carlson, Stefan FaganKelly, Stephen Maksim, Steven Miller The coherence time of a cold/ultracold atom interferometer is dependent on multiple factors. For the purposes of atom interferometry the ``mirrors'' that form the arms of the atom interferometer are a source of decoherence. An atom interferometry mirror is commonly a well defined laser pulse or the classical turning points of the atoms oscillating in the trapping potential. In an ideal situation all of the atoms will experience the same phase change at the mirror. However, in practice there is a velocity dependent phase change for laser pulse mirrors and the classical turning points. In the classical turning point case, the velocity dependence can be eliminated by creating an ideal harmonic potential so the oscillation period is independent of the energy. We have analyzed and tested the conditions necessary to create a nearly ideal harmonic potential using a standard IoffePrichard trapping configuration with a variable coil spacing. The optimal coil spacing that cancels the 4th order contribution to the trapping potential is $L/R \approx 1.2$ where $2L$ is the distance between the coils and $R$ is the coil radius. The 6th order contribution to the potential may also be minimized by operating slightly from the point where the 4th order contribution is canceled. [Preview Abstract] 

Q1.00123: Exploring the robustness of a noise correlation resonance in a Zeeman EIT system Shannon O'Leary, Michael Crescimanno, Henry Strehlow, Chad Snider Using a single diode laser with large phase noise (linewidth $\sim $100MHz) resonant with Zeeman EIT in rubidium vapor, we examine intensity noise correlations of orthogonallypolarized laser components. A sharp correlation feature ($\sim $100 Hz) is shown to be powerbroadening resistant at low powers. However, the limitations of this resistance are revealed, with the onset of a powerbroadening regime once a threshold power is crossed. Possible mechanisms for this broadening, due to decoherence of the ground state superposition, are experimentally explored and results are compared to a model. Understanding the limits of this noise correlation feature is essential to practical applications such as magnetometry. [Preview Abstract] 

Q1.00124: Electron Matter Optics and the Quantum Electron SternGerlach Magnet Scot McGregor, Roger Bach, Xiaolu Yin, SyHwang Liou, Herman Batelaan, Glen Gronniger We explore electron interferometry for the purpose of performing fundamental quantum mechanical experiments and sensing applications. To this end electron matter optics elements, in particular, a diffraction limited single slit, a double slit, and a nanofabricated grating diffraction apparatus as well as a MachZehnder IFM [1] were previously developed. The double slit diffraction pattern has been recorded one electron at a time. Furthermore, the capability of closing each slit on demand has been developed, in that way realizing the thought experiment that Feynman explains in his lectures. The capability of the MachZehnder interferometer to sense DC and AC electromagnetic fields for industrial applications is currently under investigation. Also, the construction of a new type of interferometer that has the potential to significantly increase the enclosed area and thus its sensitivity is in progress. Finally an idea to separate an electron beam fully into its two spin component using an electron interferometer is presented [2].\\[4pt] [1] G Gronniger~\textit{et al}~2006~\textit{New J. Phys.}~8~224\\[0pt] [2]~S. McGregor\textit{ et al}, Submitted for publication in NJP (2010) [Preview Abstract] 

Q1.00125: QUANTUM AND/OR NONLINEAR OPTICS 

Q1.00126: Photon Quantum Mechanics in the Undergraduate Curriculum Brett Pearson, Zack Carson, David Jackson Although it has been discussed for centuries, the true nature of light is still being debated. In fact, the quantum mechanical aspects of light have only been observed within the past 30 years. Recent advances in technology have decreased the complexity of such tests, and the Department of Physics and Astronomy at Dickinson College has worked to infuse various quantum optics experiments throughout our curriculum. We describe a set of experiments that includes the existence of photons, singlephoton interference, the quantum eraser, and tests of Bell's theorem. A primary motivation is bringing undergraduate students face to face with some of the fascinating and subtle aspects of quantum mechanics in a handson setting. [Preview Abstract] 

Q1.00127: Correlated twophoton generation by diamond atomic system in Yb atoms Tai Hyun Yoon, Minsoo Song We study a nondegenerate correlated twophoton generation with narrow bandwidths of 50 MHz by using a diamond atomic system in the collimated Yb atomic beam. We excited the 6s2 1S0 atoms into the 6s7s 1S0 excited state by the resonant twophoton transition via the intermediate 6s6p 1P1 state. Then, the excited atoms decay spontaneously into the 6s2 1S0 ground state via the intercombination 6s6p 3P1 state. We are focusing on the closedloop twophoton absorption/excitation path through which correlated two photons having the wavelengths of 611.3 nm (Stokes) and 556.8 nm (antiStokes) can be generated efficiently. We performed first a twophoton absorption spectroscopy for the 1S01P11S0 twophoton transitions. An ECDL at 399 nm was used to excite the 1S01P1 transition and another ECDL at 1077 nm was used to excite the 1P11S0 transition. From the spontaneous twophoton emission process, we were able to detect correlated twophotons at 611.3 nm and 555.8 nm at the plane perpendicular to the excitation beams, and parallel to the Yb atomic beam. We detected a few times of 106 photons per second both at the idler and signal beams at the condition of twophoton resonance with the detection solid angle of only 0.01 sr. We also performed an optical switching and modulation experiments of the photonpair by optically switching and frequency modulation of the 399nm driving field. [Preview Abstract] 

Q1.00128: Suppresion of modulation transfer signal for twolevel atoms with open transition Junyeon Won, Minjeong Seo, HeungRyoul Noh, Long Zhe Li, JongDae Park, ChangHo Cho, Sang Eon Park In a modulation transfer spectroscopy, the frequency modulated pump beam propagates collinearly with the counterpropagating unmodulated probe beam. From the nonlinear interaction of the carrier, sideband, and the probe photons, the probe beams oscillating at the frequencies shifted upward and downward by the modulation frequency of the pump beam are generated. By beating these generated signals with the original probe beam, the inphase and quadrature phase signals oscillating at the modulation frequency are measured. In the case of an open transition, the modulation transfer signal becomes suppressed. It is found that the important ingredient of observing strong modulation transfer signal is the long interaction time of atoms with the lasers. [Preview Abstract] 

Q1.00129: ABSTRACT WITHDRAWN 

Q1.00130: Electromagnetically Induced Transparency in an Open VType Molecular System Angelos Lazoudis, Teodora Kirova, Ergin Ahmed, Peng Qi, John Huennekens, Marjatta Lyyra We report experimental observation of Electromagnetically Induced Transparency (EIT) in an inhomogeneously broadened Vtype molecular vapor of Na$_{2}$. We present a theoretical analysis for both closed and open systems. For the closed system, which involves only the energy levels required to create the coherence, our results indicate that saturation is responsible for a dip of modest depth in both co and counterpropagating geometries. However, EIT dramatically increases the dip in the copropagating case and fills in the dip in the counterpropagating case. In the open system, which includes mechanisms for decay to additional energy levels, as is common in molecular systems, the saturation dip is much deeper. Again, EIT tends to deepen the dip in the copropagating case and partially fills it in the counterpropagating case. The observed feature in the counterpropagating case cannot be easily distinguished from saturation. However, the deep dip in the experimental copropagating signal can reasonably be associated in part to EIT. Supported by NSF PHY 0555608, PHY 0855502, and PHY 0968898. [Preview Abstract] 

Q1.00131: Role of NonLinear Interactions in ElectromagneticField Propagation through Moving ManyElectron Atomic Systems Verne Jacobs Reduceddensitymatrix descriptions are developed for the propagation of electromagnetic fields through moving manyelectron atomic systems, taking into account centerofmass motions, atomic collision processes, and applied magnetic fields. Timedomain (equationofmotion) and the frequencydomain (resolvent operator) formulations are developed in a unified manner. A semiclassical perturbative treatment of the electromagnetic interaction is employed to derive compact Liouville space operator expressions for the general n'thorder nonlinear macroscopic electromagneticresponse tensors. Coherent atomic excitations and the full tetradic matrix form of the collisionradiative selfenergy operator in the Markov approximation are taken into account. [Preview Abstract] 

Q1.00132: Lorentz and optical Bloch models of Ramsey fringes James Supplee, Robert K. Murawski Studying one optical effect both classically and quantum mechanically can allow students to use the more familiar Lorentz model to build intuition about the twolevel optical Bloch model, as well as to better understand the effect being studied. This poster gives an educational example in which each model is used to plot atomic excitation versus detuning for singlepulse and for twopulse driving fields, hence illustrating the widelyused resonance narrowing achieved by the twopulse Ramsey scheme. The Lorentz model, applied to this case, also allows for fun exercises in transforming to the frequencydomain to check one's understanding of some results, and those checks do not carry over fully to the Bloch model. Students can investigate the range of validity of the Lorentz model and note the physics behind the onset of nonlinearities by exploring why the models differ as inversion increases near resonance. This example provides exercises in comparing, for the two models: equations of motion; dipole oscillation predictions (harmonic oscillator motion versus Bloch sphere visualization); and linewidth predictions. [Preview Abstract] 

Q1.00133: ABSTRACT WITHDRAWN 

Q1.00134: Probe spectrum and photon statistics of multilevel atoms in a resonant twomode cavity James Clemens We calculate the probe spectrum and photon statistics for a collection of atoms with a degenerate multilevel structure such as the $F=3$ to $F^\prime =4$ transition in $^{85}$Rb coupled to a resonant cavity supporting two modes with orthogonal polarization. We numerically simulate the photon counting statistics and calculate the normalized second order intensity auto and crosscorrelations for the two cavity modes and the spontaneous emission from the side of the cavity using quantum trajectory theory. We compare our results with those for simplified three and fourlevel atomic models which have been solved analytically in the limit of weak driving. [Preview Abstract] 

Q1.00135: Cavity QED with group II atoms Murray J. Holland, Dominic Meiser, David Tieri Traditionally, cavity QED experiments and theory have focused on strong atomic transitions so as to maximize the coupling strength of atoms to cavity photons. Recently novel cavity QED systems using ultranarrow optical transitions have started to attract attention. In these systems the coupling between atoms and field is much weaker but at the same time the decoherence of the atoms is also much weaker. As a result, nontrivial quantum effects can be studied that are of a different character than in conventional cavity QED systems. For example these systems permit the realization of steady state superradiance and the study of the continuous crossover from the laser to superradiance, leading to a unification of the theories of these two phenomena. Other avenues of research opened up by these systems are in the areas of ultrahigh precision spectroscopy and optical atomic clocks, nonlinear optics, and quantum information and simulation. [Preview Abstract] 

Q1.00136: On nearestneighbor interactions of cold polar molecules in twocolor arrays T. Bragdon, S.F. Yelin We analyze the interaction dynamics of polarized molecules excited from ground rot.vib. states in twocolor optical arrays as a periodic structure of two interacting dipoles with the aim of improved interaction clarity, namely, where nearestneighbor interactions predominate. We also discuss connections to emergent manybody dynamics and enhanced optical nonlinearity in these arrays. [Preview Abstract] 

Q1.00137: A nanoscale quantum interface for single atoms Jeff Thompson, Tobias Tiecke, Alexey Akimov, Chun Yu, Darrick Chang, Alexander Zibrov, Vladan Vuletic, Hongkun Park, Mikhail Lukin Neutral atoms are ideal quantum systems: they have long groundstate coherence times and strong optical cycling transitions that enable state detection and preparation. Building quantum networks of atoms interacting through photons is challenging, however, as many schemes for atomphoton interaction are inefficient or hard to scale. We propose a scheme to trap neutral atoms near silver nanowires, which are tightly confining waveguides for surface plasmons. The nanowire tip is used to generate a nearfield optical trapping potential, and to enhance and efficiently collect spontaneous emission from the atom. For our experimental parameters, the enhancement may be up to a factor of 10, with a corresponding collection efficiency of 90\%. In this poster, we will focus on recent experimental progress. [Preview Abstract] 

Q1.00138: ENTANGLEMENT, DECOHERENCE, AND ERROR CORRECTION 

Q1.00139: Modeling the noise power spectrum of a quantum point contact coupled to a nanomechanical oscillator David Stopher, D.H. Santamore The experiments of Rimberg et al. (Nature 466, 86 (2010)) inadvertently illuminated the entanglement of a quantum point contact (QPC) with the twodimensional electron gas (2DEG) on which the QPC is constructed. Acting as a nanomechanical oscillator, the 2DEG couples to the QPC in such a way that the current passing through the QPC fluctuates in a manner highly suggestive of shot noise. Historically, such QPC coupling has been treated as a relationship between the tunneling electron and the external system. However, the experimental results of Rimberg et al. indicate that the quantum noise arises from the coupling of the 2DEG not with the tunneling electron but rather with the electrons in the reservoirs on either side of the QPC. We investigate this mechanism and provide a theoretical framework for comprehension of this phenomenon. Specifically, we derive a twotime correlation function of the current in order to obtain the noise power spectrum. [Preview Abstract] 

Q1.00140: Multiqubit nonseparability in families of entangled pure states Shohini Ghose, Amir JafariSalim Multiqubit entanglement is a crucial ingredient for largescale quantum information processing and can also play a role in quantum criticality phenomena in condensed matter systems. Entanglement between qubits can lead to violations of Belltype inequalities, indicating the nonlocal nature of the correlations between qubits. We investigate genuine multiqubit nonlocality in families of entangled multiqubit pure states by analyzing the SvetlichnyBell inequality that is violated only if all qubits are nonlocally correlated. We derive a relationship between multiqubit entanglement and nonlocality for Nqubit generalized GHZ states, and identify a subset of these states that do not violate the SvetlichnyBell inequality. The location of the boundary between the states that do violate the inequality and those that don't is the same for all N. On the other hand, all members of a set of states called the maximal slice states violate the Svetlichny inequality and analogous to the 2qubit case, the amount of violation increases with the amount of entanglement. Our results raise questions regarding the connection between multiqubit entanglement and nonlocality. [Preview Abstract] 

Q1.00141: Entanglement Dynamics in Harmonic Oscillator Chains Razmik Unanyan, Michael Fleischhauer We study the longtime evolution of the bipartite entanglement in translationally invariant gapped harmonic lattice systems with finiterange interactions. A lower bound for the von Neumann entropy is derived in terms of the purity of the reduced density matrix. It is shown that starting from an initially Gaussian state the entanglement entropy increases at least linearly in time. This implies that the dynamics of gapped (noncritical) harmonic lattice systems cannot be efficiently simulated by algorithms based on matrixproduct decompositions of the quantum state. [Preview Abstract] 

Q1.00142: QUANTUM COMPUTATION 

Q1.00143: Quantum Information Processing using Scalable Techniques D. Hanneke, R. Bowler, J.D. Jost, J.P. Home, Y. Lin, T.R. Tan, D. Leibfried, D.J. Wineland We report progress towards improving our previous demonstrations that combined all the fundamental building blocks required for scalable quantum information processing using trapped atomic ions. Included elements are longlived qubits; a laserinduced universal gate set; state initialization and readout; and information transport, including cotrapping a second ion species to reinitialize motion without qubit decoherence. Recent efforts have focused on reducing experimental overhead and increasing gate fidelity. Most of the experimental duty cycle was previously used for transport, separation, and recombination of ion chains as well as recooling of motional excitation. We have addressed these issues by developing and implementing an arbitrary waveform generator with an update rate far above the ions' motional frequencies. To reduce gate errors, we actively stabilize the position of several UV (313 nm) laser beams. We have also switched the twoqubit entangling gate to one that acts directly on $^9\textrm{Be}^+$ hyperfine qubit states whose energy separation is magneticfluctuation insensitive. [Preview Abstract] 

Q1.00144: A universal gate set on a TrappedIon Optical Qubit using a narrow linewidth Diode laser Yinnon Glickman, Nitzan Akerman, Shlomi Kotler, Anna Kesselman, Roee Ozeri Optical qubit states are encoded in the 5S$_{1/2}$ ground state and the metastable 4D$_{5/2}$ level in a single trapped $^{88}$Sr$^+$ ion, connected by a narrow optical quadruple transition. A 674nm diode laser is frequency stabilized and narrowed to a linewidth below 80 Hz. Using this laser we demonstrate a universal quantum gateset as well as other coherent operations on the ions' internal and external degrees of freedom. Rabi flopping, Ramsey spectroscopy and ground state cooling of the qubit are performed. Using a bichromatic beam, two ionqubits are entangled with a SorensonMolmer entangling gate scheme. The advantages and disadvantages of using a diode laser to this end are discussed. In particular, the contribution of fast phase noise, typical to diode laser systems, to offresonance qubit excitation and gate error is analyzed. [Preview Abstract] 

Q1.00145: Towards Coupling Neutral Atoms to a Superconducting Resonator at 20 mK J.A. Grover, J.E. Hoffman, Z. Kim, K.D. Voigt, A.K. Wood, J.R. Anderson, A.J. Dragt, M. Hafezi, C.J. Lobb, L.A. Orozco, S.L. Rolston, J.M. Taylor, C.P. Vlahacos, F.C. Wellstood, P. Solano Recent proposals in quantum computing center on the creation of hybrid quantum processors. Here we report progress on an experiment to couple an ensemble of $^{87}$Rb atoms to a superconducting, thinfilm LC resonator at 20 mK through a magnetic dipole transition. We have demonstrated tuning of the LC resonator to within 2 kHz of the 6.8GHz hyperfine splitting of $^{87}$Rb. The next step is to trap the atoms around a subwavelength optical fiber using a twocolor, evanescent wave dipole trap. This will allow us to bring the atoms less than 10 $\mu$m above the surface of the superconductor without producing excessive heating. We seek to provide proof of principle for interfacing a stable quantum memory, the $^{87}$Rb atoms, to superconducting qubits. [Preview Abstract] 

Q1.00146: Toward Quantum Simulation with $^9$Be$^+$ Ions in a Penning Trap Brian Sawyer, Joe Britton, Hermann Uys, Michael Biercuk, John Bollinger Experimental progress in the fields of atomic and molecular physics has allowed exquisite control over ensembles of cold and ultracold ions, neutral atoms, and polar molecules. A number of theoretical proposals have been put forward concerning direct simulation of quantum Hamiltonians in these systems. We report progress toward simulation of the transverse Ising model in a twodimensional Coulomb crystal of $\sim$100 $^9$Be$^+$ ions confined within a Penning trap. Coupling between ions is controlled via optical dipole forces, thereby facilitating a wide range of interparticle interactions including infiniterange and nearestneighbor coupling. Furthermore, the triangular lattice structure readily obtained within the planar Coulomb crystal allows for simulation of spin frustration in an antiferromagnetic system. Given our large ensembles of trapped $^9$Be$^+$, it may be possible to perform quantum simulations that are currently intractable with classical computers. [Preview Abstract] 

Q1.00147: Rydberg molecules mediated interaction between polar molecules: a new tool to realize twoqubit gates Elena Kuznetsova, Seth Rittenhouse, Susanne Yelin, Hossein Sadeghpour We propose and analyze coherent coupling of ground state polar molecules and Rydberg atoms as a way to enhance the interaction strength between molecules. Ultracold polar molecules placed in periodic arrays of traps represent an attractive system for quantum information processing. Polar molecules that can be currently produced at ultracold temperatures by Feshbach and photoassociation are limited to alkali dimers, having permanent dipole moments of the order of 1 Debye. It limits the distance at which molecules can efficiently interact via dipoledipole interaction to ~ 100 nm, i.e. to a few nearest neighbors. The interaction strength can be significantly increased by coupling molecules to Rydberg atoms, a process in which they form a Rydberg molecule. The states of a Rydberg molecule can have dipole moments of thousands Debye, increasing the effective interaction distance up to several $\mu$m. The Rydberg molecular states depend on the initial state of a polar molecule, allowing to realize statedependent interaction between them. We analyze the feasibility of performing a phase gate with KRb and RbCs molecules coupled to Rb Rybderg atoms. [Preview Abstract] 

Q1.00148: Implementing a C$_k$NOT gate using Rydberg blockade Larry Isenhower, Mark Saffman Multibit quantum gates are efficient primitives for quantum error correction and other algorithms. We report on an analysis of the fidelity and error scaling of a C$_k$NOT gate (CNOT gate with $k$ control bits) using Rydberg blockade. Provided all $k+1 $ bits lie within a blockade radius the gate can be implemented using a sequence of $2k+1$ Rydberg pulses. This is a more efficient scaling than would be obtained by decomposing the C$_k$NOT into one and two qubit gates. [Preview Abstract] 

Q1.00149: Nonlinear Optics Quantum Information Processing with Microwave Photons Prabin Adhikari, Mohammad Hafezi, Jake Taylor One approach to quantum information processing\footnote{``A Scheme for Efficient Quantum Computation with Linear Optics,'' E. Knill, R. Laflamme, G.J. Milburn (Nature, Vol 409, 4 January 2001)} is to use photons as quantum bits and rely on the robustness of linear optical elements. However, some optical nonlinearity is necessary to enable universal quantum computing. Here we suggest a circuitQED approach to~ implementing a deterministic twophoton phase gate for such computing. Our specific example considers an LC resonator coupled to a flux qubit. Using this model, we show how fast twoqubit gates between photons are possible, and compute limitations of these ideas based on current technology. [Preview Abstract] 

Q1.00150: Driving Trapped Molecular Ions with a Microwave Transmission Line David Meyer, Adam McCaughan, Anders Mortensen, Paul Antohi, Arolyn Conwill, Karl Berggren, Isaac Chuang Trapped ion quantum computing builds on the strengths of ions as qubits: they can be trapped for hours with coherence times exceeding tens of seconds. Polar molecular ions have a further advantage as their rotational transitions are in the microwave frequency regime and can be electronically read and controlled. Driving these transitions requires the ions be placed in large electric fields that are achievable through the integration of planar ion traps with a superconducting coplanar waveguide (CPW) transmission line. Our novel trap design successfully trapped and crystallized Sr+ ions and trapped a mixed species cloud of Sr+ and SrCl+. Microwave signals sent through the transmission line under a mixed cloud could drive the rotational transitions of SrCl+ and would cause sympathetic heating of Sr+ ions, which is detectable through a change in fluorescence. This work will help enable quantum computation with polar molecular ions [Preview Abstract] 

Q1.00151: Neutral atom quantum computer of Cs atoms in a 5$\mu$m spaced 3D optical lattice Theodore A. Corcovilos, Xiao Li, Yang Wang, David S. Weiss, Hoon Ryu, Felix Lu, Jungsang Kim We present an approach to quantum computing using lasercooled single Cs atoms in a 5$\mu$m spaced 3D optical lattice. Single qubit operations can be accomplished with a combination of acStark shifting addressing beams and microwaves. Rapid steering of the lasers using micromirrors allows target atoms to be changed in tens of $\mu$s. Singlesite addressing combined with lattice polarization rotation enables us to fill voids in the central region of the atom array by selectively moving individual atoms. We will also describe progress toward executing pairwise entanglement operations. [Preview Abstract] 

Q1.00152: Collecting light emitted by a single atom into a single optical mode Rachel Noek, Taehyun Kim, Emily Mount, Daniel Gaultney, Andre van Rynbach, Caleb Knoernschild, Peter Maunz, Jungsang Kim Connecting trapped ions with a photonic quantum link is a promising approach for long distance quantum communication and large scale quantum computation. Entanglement, quantum teleportation, private random number generation and a quantum gate [1] have been demonstrated between remote trapped ions. These probabilistic remote quantum operations can be made deterministic by using local Coulomb gates; however, the success probability is limited by the photon collection probability into a single mode and is currently too small to be useful. Here, we investigate the use of a cavity with a tightly focused mode and, alternatively, a spherical micro mirror in order to improve the photon collection from single trapped ions. Furthermore, we will report experimental progress on the realization of an ion trap within a cavity formed by a highreflectance coated fiber tip and a spherical mirror. The rfPaul trap will be patterned directly on the tip of a fiber ferrule. \\[4pt] [1] P. Maunz, et al., \textit{Phys. Rev. Lett.} 102, 250502 (2009). [Preview Abstract] 

Q1.00153: PROGRESS IN CAVITY OPTOMECHANICS 

Q1.00154: AllOptical Optomechanics: An Optical Spring Mirror Swati Singh, Gregory Phelps, Dan Goldbaum, Ewan Wright, Pierre Meystre The dominant hurdle to the operation of optomechanical systems in the quantum regime is the coupling of the vibrating element to a thermal reservoir via mechanical supports. Here we propose a scheme that uses an optical spring to replace the mechanical support. We show that the resolvedsideband regime of cooling can be reached in a configuration using a highreflectivity disk mirror held by an optical tweezer as one of the end mirrors of a FabryPerot cavity. We find a final phonon occupation number of the trapped mirror ${\bar n}$= 0.56 for reasonable parameters, the limit being set by our approximations, and not any fundamental physics. This demonstrates the promise of dielectric disks attached to optical springs for the observation of quantum effects in macroscopic objects. [Preview Abstract] 

Q1.00155: Generation of squeezing: magnetic dipoles on cantilevers HyoJun Seok, Swati Singh, Steven Steinke, Pierre Meystre We investigate the generation of motional squeezed states in a nanomechanical cantilever. Our model system consists of a nanoscale cantilever  whose centerofmass motion is initially cooled to its quantum mechanical ground state  magnetically coupled a classically driven mechanical tuning fork. We show that the magnetic dipoledipole interaction can produce significant phonon squeezing of the centerofmass motion of the cantilever, and evaluate the effect of various dissipation channels, including the coupling of the cantilever to a heat bath and phase and amplitude fluctuations in the oscillating field driving the tuning fork. [Preview Abstract] 

Q1.00156: Coupling a Bose condensate to micromechanical oscillators Chandler Kemp, Eli Fox, Scott Flanz, Mukund Vengalattore We describe the construction of a compact apparatus to investigate the interaction of a spinor BoseEinstein condensate and a micromechanical oscillator. The apparatus uses a double magnetooptical trap, Raman sideband cooling, and evaporative cooling to rapidly produce a $^{87}$Rb BEC in close proximity to a high Q membrane. The micromotion of the membrane results in small Zeeman shifts at the location of the BEC due to a magnetic domain attached to the oscillator. Detection of this micromotion by the condensate [1] results in a backaction on the membrane. We investigate prospects of using this backaction to generate nonclassical states of the mechanical oscillator [2]. \\[4pt] [1] M. Vengalattore {\em et al}, Phys. Rev. Lett. \textbf{98}, 200801 (2007);\\[0pt] [2] S. Singh {\em et al}, ``Quantifying measurement backaction on a macroscopic object: BEC magnetometry on mechanical oscillators.'' (to be published) [Preview Abstract] 

Q1.00157: A cavity optomechanical system for a microwave to optical quantum link Thomas Purdy, Ray Simmonds, Konrad Lehnert, Cindy Regal Cavity mechanics in both the optical and microwave domains is rapidly progressing to where the quantum interactions between photons and a micromechanical resonator are evident. If microwave and optical photons can both be coupled to a single mechanical resonator, one application is the coherent transfer of quantum information from the microwave to the optical field or vice versa. We present progress toward such a hybrid system where a thin, partiallymetalized dielectric membrane forms one plate of a capacitor in a superconducting microwave LC circuit and is dispersively coupled to a highfinesse optical cavity. Vibrations induced in the membrane by microwave coupling may be transduced onto the optical field, if environmental decoherence is small. In our current research on the optical side of the experiment, we are developing an optical cavity that realizes the required coupling to the dielectric membrane. Such an optomechanical system must be compatible with a cryogenic environment that is necessary both for superconducting circuits and to reduce thermal decoherenece in the mechanical resonator. [Preview Abstract] 

Q1.00158: APPLICATIONS OF AMO SCIENCE 

Q1.00159: Nuclear Magnetic Resonance Gyroscope Michael Larsen The navigation grade micro Nuclear Magnetic Resonance Gyroscope (microNMRG) being developed by the Northrop Grumman Corporation is currently in phase 4 of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. The microNMRG technology is pushing the boundaries of size, weight, power, and performance allowing new small platform applications of navigation grade Inertial Navigation System (INS) technology. Information on the historical development of the technology, basics of operation, task performance goals, application opportunities, and a phase 2 sample of earth rate measurement data will be presented. [Preview Abstract] 

Q1.00160: Using cold atoms as a bright cw source for monochromatic ion and electron beams Yoann Bruneau, Joshua Gurian, Andrea Fioretti, Daniel Comparat, Pierre Pillet, Leila Kime, Bernard Rasser, Pierre Sudraud Stateoftheart thermal ion and electrons sources have reached a level of performance primarily limited by a high source temperature. Here we report progress in using ionized ultracold atoms to create continuous ion and electrons sources. This new source uses a large laser cooled sample of Cs atoms, promoted to Rydberg states before undergoing field ionization. The low velocity dispersion and large sample size should allow for superior, in terms of both brightness and energy dispersion, ion and electron sources. Strong focusing of low energy beams are shown to be possible using SIMION and General Particle Tracer (GPT) charged particle optics software products simulations. [Preview Abstract] 

Q1.00161: LongLived Nuclear Spin Singlet States in Molecules Stephen DeVience, Matthew Rosen, Ronald Walsworth Nuclear spins in molecules can be paired to create singlet states with lifetimes much longer than the single spin T1. We create and characterize such singlet states using protons in organic molecules and discuss the effects of temperature, applied RF fields, and chemical exchange. We discuss potential uses of these states in biomedical imaging and as NMR probes in condensed matter systems. [Preview Abstract] 

Q1.00162: A multichannel portable SERF atomic magnetometer for biomagnetic measurement Robert Wyllie, Matthew Kauer, Gregory Smetana, Ronald Wakai, Thad Walker We present a portable fourchannel atomic magnetometer array operating in the spin exchange relaxationfree regime. Each channel was operated with a baseline sensitivity of 510 fT$/{\sqrt{\textmd{Hz}}}$, at or near the expected Johnson noise limit of the mumetal shielding. The magnetometer array has several design features intended to maximize its suitability for fetal magnetocardiography, such as a compact modular design, fiber coupled lasers, and magnetometer channel spacing adjustable from 510cm. We present adult magnetocardiogram using this array in a magnetically shielded room. We also show the acquisition and analysis of phantom fetal signals with a peak QRS amplitude of $\sim$1pt, using an advanced nonlinear denoising algorithm. [Preview Abstract] 

Q1.00163: Lithium Ion Microscope Based on a MagnetoOptical Trap B. Knuffman, A.V. Steele, M. Maazouz, J. Orloff, J.J. McClelland Focused ion beams (FIBs) are an invaluable tool for the creation and characterization of materials with nanoscale feature sizes. Recently, significant interest has been generated by emerging ion source technologies that expand the range of elemental species (over the widely available gallium source) that can be used to form FIBs chosen to suit specific applications. We have created a lithium FIB based on magnetooptical trap ion source (MOTIS) technology. The MOTIS employs lasercooled neutral atoms that are photoionized to create an isotopically pure beam of ions appropriate for focusing to a nanoscale probe using conventional ion optics. We have achieved a focal spot size of less than 30 nm at a low 2 keV beam energy and expect sub10 nm performance at typical FIB operating energies near 30 keV. We will present high resolution images obtained by scanning the focused lithium beam on a sample and collecting secondary electrons emitted from the surface. [Preview Abstract] 

Q1.00164: Atom counting system to measure ultralow Kr85 contamination in liquid xenon dark matter detectors Tae Hyun Yoon, Claire Allred, Luke Goetzke, Elena Aprile, Tanya Zelevinsky The XENON experiment aims at the direct detection of dark matter in the form of Weakly Interacting Massive Particles (WIMPs) via their elastic scattering off Xe nuclei. For Xe targets, Kr contamination contributes background events through beta decay of radioactive $^{85}$Kr. To achieve the required sensitivity, it is necessary to suppress Kr contamination of Xe to the part per trillion (ppt) level. We have developed and are currently testing a single Kr atom counting apparatus using the Atom Trap Trace Analysis method. The lowlevel atom number measurement is made possible by cooling and trapping metastable Kr atoms with magnetooptical techniques and detecting their laser fluorescence with a sensitive photodetector. Since Ar and Kr have similar wavelengths, the coldatom apparatus has been initially tested with Ar to avoid contamination. Results from tests with both Ar and Kr will be presented. [Preview Abstract] 

Q1.00165: Lowfield MRI for studies of human pulmonary physiology and traumatic brain injury Alyssa Wilson, Stephen DeVience, Matthew Rosen, Ronald Walsworth We describe recent progress on the development of an openaccess lowmagneticfield MRI system for studies of human pulmonary physiology and traumatic brain injury. Lowfield MRI benefits from reduced magnetic susceptibility effects and can provide highresolution images of the human body when used with hyperpolarized media such as 3He and 129Xe. [Preview Abstract] 

Q1.00166: Selfcontained fibercoupled atomic magnetometers Frank Shu, Guanghai Jin, Tom Kornack, Jeffrey Norell, Antonije Radojevic, Joseph Kinast, Ekaterina Mehnert, Nezih Dural, Michael Romalis Atomic magnetometers using a dense alkalimetal vapor have reached magnetic field sensitivities on the order of 200 aT/Hz$^{1/2}$, exceeding the sensitivity of best SQUID magnetometers.\footnote{H.B. Dang, A.C. Maloof, and M.V. Romalis, Appl. Phys. Lett. 97, 151110 (2010)} They are also relatively simple devices amenable to miniaturization and mass production. We are developing a fibercoupled selfcontained atomic magnetometer based on wellestablished fiber optic fabrication techniques. The magnetometer incorporates a RbCs hybrid alkalimetal cell and a nonmagnetic light polarization modulator for sensitive polarimetry. An array of such sensors can be used for magnetoencephalography and many other applications. [Preview Abstract] 

Q1.00167: POSTDEADLINE POSTERS 

Q1.00168: Subnanoscale Resolution for Microscopy via Coherent Population Trapping Kishor T. Kapale, Girish S. Agarwal We present a coherent population trapping based scheme to attain subnanoscale resolution for microscopy. Our method uses threelevel atoms coupled to amplitude modulated probe field and spatially dependent drive field. The modulation of the probe field allows us to tap into the steep dispersion normally associated with electromagnetically induced transparency and offers an avenue to attain sub nanometer resolution using just optical fields. We illustrate application of the techniques to the area of microscopy, show how multilevel schemes offer the possibility of improving resolution further, and discuss extensions beyond single spatial dimension. [Preview Abstract] 

Q1.00169: Dissipationinduced squeezing Gentaro Watanabe, Harri M\"akel\"a We present a method to create phase and numbersqueezed states in twomode Bose systems using dissipation. The effectiveness of this method is demonstrated by considering cold Bose gases trapped in a doublewell potential. The extension of our formalism to an optical lattice gives control of the phase boundaries of the steadystate phase diagram, and we discover a new phase characterized by a nonzero condensate fraction and thermallike particle number statistics. We also show how to perform amplitude squeezing for singlemode photons using dissipation. [Preview Abstract] 

Q1.00170: Phillips line and the universality in elastic threebody collisions Vladimir Roudnev, Michael Cavagnero We investigate the universal properties of threebody systems below the breakup threshold. The threebody scattering length and the threebody bound state closest to the threshold are strongly correlated. We study the dependence of the correlation on the details of the interaction and the mass ratios of the constituents. Knowing and understanding properties of the Phillips line can help in practical estimations of the properties of various molecular threebody systems. [Preview Abstract] 

Q1.00171: Strong Perturbation and Multiple Electron Emission in Highly Charged Ion Atom Collisions Siegbert Hagmann, Liao ChunLei Since Saris pioneering discovery of radiation from the quasimolecule transiently formed during adiabatic collisions of heavy highlycharged (HCI) ions with atoms the dynamics of electrons during the collisions has intrigued experimentalists and theorists. We show that for strongly perturbing collisions of HCI with atoms topologically highly confined electron emission takes place out of the compound. While the independent electron approximation does account well for simultaneously measured swift collisions the experiments are at variance with theoretical predictions. [Preview Abstract] 

Q1.00172: Hightemperature Gas Reactor (HTGR) Sajad Abedi General Atomics (GA) has over 35 years experience in prismatic block Hightemperature Gas Reactor (HTGR) technology design. During this period, the design has recently involved into a modular have been performed to demonstrate its versatility. This versatility is directly related to refractory TRISO coated  particle fuel that can contain any type of fuel. This paper summarized GA's fuel cycle studies individually and compares each based upon its cycle sustainability, proliferationresistance capabilities, and other performance data against pressurized water reactor (PWR) fuel cycle data. Fuel cycle studies LEUNV;commercial HEUTh;commercial LEUTh;weaponsgrade plutonium consumption; and burning of LWR waste including plutonium and minor actinides in the MHR. results show that all commercial MHR options, with the exception of HEUTH, are more sustainable than a PWR fuel cycle. With LEUNV being the most sustainable commercial options. In addition, all commercial MHR options out perform the PWR with regards to its proliferationresistance, with thorium fuel cycle having the best proliferationresistance characteristics. [Preview Abstract] 

Q1.00173: Adiabatic Transfer of Light in a Double Cavity Nicholas Chisholm, Nicholas Miladinovic, Faiyaz Hasan, Ian Linnington, Ed Hinds, Duncan O'Dell We perform a simple theoretical analysis of the problem of two optical cavities coupled by a common mirror which is movable. The mirror position controls the electromagnetic mode structure of the double cavity. Modes can be transferred from one side to the other by moving the mirror, thereby allowing deterministic and ondemand transfer of photons between two cavities. By mapping the Maxwell wave equation onto the Schrodinger wave equation, we are able to make use of the LandauZener result for the transition probability at an avoided crossing to obtain the conditions for adiabatic transfer. [Preview Abstract] 

Q1.00174: Origin of the Mass Han Yongquan Mass originates form velocity, which is determined by the total sum of interior and exterior velocities of the object. No matter how big the difference between the volume sizes of two objects is, as long as their sum of interior and exterior velocities equals, their mass would be the same. It can be said that the mass of an electron is equal to one kilogram. It is theoretically inferred that positron and negatron are the smallest particles composing matter. Mass is directly proportional to velocity and proportionality constant k is equal to 4.2$\times 10^{45}$. It can be written in the form of$m=k\times v$.If m is 1 kilogram, velocity is $v=2.38\times 10^{44}$ meters/second, which means that as long as the velocity of an electron reaches this numerical value and then its mass is 1 kilogram. Any particle's mass could be 1 kilogram, as long as its total sum of interior and exterior velocities reaches this numerical value. Electromagnetic waves is the smallest particle that can Independent existence and composition material, the electron velocity in the inside of substances $v = \sqrt{\frac{Hp^2}{4mr}} = \sqrt{\frac{3.5\times 10^{104}(2.17\times10^{42})^2}{4\times 0.91\times 10^{30} \times 10^{18}}} = 2.13 \times 10^{14}$ TEL: 13241375685 [Preview Abstract] 

Q1.00175: STIRAP on sodium vapor with picosecond pulses: calculations and experiment J. Bruce Johnson, Chakree Tanjaroon, Jim L. Hicks, Susan D. Allen Calculations of STIRAP transfer efficiencies were made on sodium starting from the eight hyperfine states of the 3s ($^{2}$S$_{1/2})$ electronic ground state, passing through the eight hyperfine states of the 3p ($^{2}$P$_{1/2})$ and/or fourteen of the sixteen hyperfine states of the 3p ($^{2}$P$_{3/2})$ to the eight hyperfine states of the 5s ($^{2}$S$_{1/2})$ state. Linearly polarized light was used in calculations and experiment leading to six independent sets of coupled states (four sets of five states and two sets of nine states). Calculations were made for laser pulses several picoseconds in length and compared with experiment. Although the linewidth of the laser pulses used in both computation and experiment was a small fraction of the fine structure splitting between the 3p states, both finestructure states were observed to contribute to the STIRAP transfer efficiency. A rich set of results was found including oscillations similar to the Rabi oscillations observed in twostate systems when the pump and Stokes pulses were tuned to wavelengths between the two 3p states. [Preview Abstract] 

Q1.00176: Critical parameters and exact number of bound states for central potentials Evgeny Liverts Quantum states of zero energy are defined as the transition between bound states of negative energy and free states of positive energy. The boundary conditions for the transition states as solutions of the nonrelativistic Schrodinger equation are determined. The critical parameters of widely used central potentials are defined as corresponding to the transition states. Two exact methods, and an approximate method of the second order WKB, were proposed for calculating the critical parameters of central potentials. The numerical results in the form of tables of the critical parameters for several well known central potentials are presented. The above results enable us to answer three important questions:~\\ i) What is the number of bound states for given central potential and given orbital quantum number $l$;~\\ ii) What is the maximum value of $l$ which can provide the bound states for the given central potential;~\\ iii) What is the order of energy levels for the given form of the central potential. [Preview Abstract] 

Q1.00177: Atomic and Nuclear Physics with Radioactive Isotopes Y. Natali Martinez de Escobar, E. Bond, A. Moody, R. Rundberg, J. Torgerson, D.J. Vieira, X. Zhao Capabilities in laser cooling and trapping, isotope production and nuclear chemistry enable us to pursue a variety of farreaching experiments at the interface of atomic and nuclear physics with radioactive isotopes. Here we highlight both recent precision polarization measurements of Rb isotopes in an optical dipole trap for a newgeneration $\beta $asymmetry measurement and our progress on characterizing the $^{229}$Th nuclear isomer. Optical pumping allows us to prepare a dipoletrapped Rb atom sample with an initial polarization of 0.972(2), measured using resolved microwave transitions. The spin polarization further purifies to 0.987(1) in 10 seconds and remains above 0.99 when the twobody collision loss rate between atoms in mixed spin states is greater than the onebody trap loss rate [1]. We also describe our progress toward directly characterizing the $^{229}$Th nuclear isomer transition and discuss our results in comparison to other published measurements. The isomer transition in $^{229}$Th (indirectlymeasured transition wavelength near 160 nm [2]) promises to be the first nuclear transition excitable with coherent laser sources. Its estimated narrow linewidth (natural lifetime $\tau \quad \sim $ 7 hr.) and wavelength make it a prime candidate to use for a nuclear clock and applicable in fields such as cosmology and metrology. [1] PRA \textbf{83}, 013416 (2011). [2] PRL \textbf{98}, 142501 (2007). [Preview Abstract] 

Q1.00178: Self Focusing and defocusing of twisted light in nonlinear media Anita Thakur, Jamal Berakdar The Selffocusing of light beams is a basic phenomena in nonlinear optics with a variety of important applications that rely on the manipulation and control of the photon beam. Generally, the theory of self focusing is well established with the propagation characteristics found to be closely related to the properties of the medium and to the pulse width of laser beams. Here, we are reporting the study of the selffocusing and defocusing of a light beam carrying orbital angular momentum (called twisted light) propagating in a nonlinear medium. We derive a differential equation for the beam width parameter $f$ as a function of the propagation distance, angular frequency, beam waist and intensity of the beam. The method is based on WentzelKramersBrillouin(WKB) and the paraxial approximations. Analytical expressions for $f$ are obtained, analyzed and illustrated for typical experimental situations. [Preview Abstract] 

Q1.00179: High Harmonic Generation from 2D Diatomic Molecules Mitsuko Murakami, Tom Kirchner, Marko Horbatsch We propose a simple model to calculate high harmonic spectra from diatomic molecules based on an independentparticle description of molecular orbitals. High harmonics are calculated from the numerical solution of the timedependent Schr\"odinger equation in a twodimensional geometry. According to this model, harmonic spectra from individual orbitals generally follow the semiclassical cutoff law, but their relative strengths vary depending on molecular orientations and driving laser intensities. In particular, when the contributions from multiple orbitals are comparably strong, their net spectra will extend to the innerorbital cutoffs but may appear to have a local minimum where the harmonic intensity of the highest occupied molecular orbital begins to fall off. This mechanism might be the underlying cause for the intensitydependent minima in molecular harmonics observed in a recent experiment by W\"orner et.al. [1]. \\[4pt] [1] H. J. W\"orner {\it et.al.}, Phys. Rev. Lett. {\bf 104}, 233904 (2010). [Preview Abstract] 

Q1.00180: Angular distributions of secondary electrons in fast particleatom scattering Miron Ya. Amusia, Larissa V. Chernysheva, Eugene Liverts We present the angular distribution of electrons knocked out from an atom in a fast charge particle collision at small momentum transfer. It is determined not only by dipole but also by quadrupole transitions, the contribution of which can be considerably enhanced as compared to the case of photoionization. There the nondipole parameters are suppressed as compared to the dipole ones by the parameter$\omega R/c\ll 1$, where $\omega $ is the photon energy, $R$ is the ionized shell radius and $c $is the speed of light. This suppression in fast electronatom collisions can be considerably reduced: the expansion parameter $\omega R/v\ll 1$ is much bigger than in photoionization, since the speed of the incoming electron $v$ is much smaller than $c$. It is essential that the ionizing field in collision process is longitudinal, while in photoionization  transversal. We present results for outer ssubshells of noble gas atoms He, Ar and Xe. Even for very small transferred momentum $q$, i.e. in the socalled optical limit, the deviation from photoionization case is prominent. Results of calculations and formula used can be found in http://arxiv.org/abs/1012.5465v1 (arXiv:1012.5465v1) [Preview Abstract] 

Q1.00181: Dipolar BEC in an Artificial Magnetic Field Zalihe \"Oz\c{c}akmakli, Cem Y\"uce In this paper, we study the dipolar BEC in an artificial magnetic field. Using the adiabatic approximation, we obtain an effective equation of motion for the atoms driven to the dark state. We discuss the influence of artificial magnetic field on the critical angular velocity for the vortex formation. [Preview Abstract] 

Q1.00182: Ultra cold atoms in a TimeModulated OneDimensional Optical Lattice Plus Harmonic Potential Saadet Burgu, Cem Y\"uce We study the quantum dynamics in a timemodulated onedimensional optical lattice plus a parabolic potential using the tightbinding approximation. We solve the dynamic equation describing the atomic motion. We report dynamic localization of a BoseEinstein condensate in a shaken optical lattice. [Preview Abstract] 

Q1.00183: KelvinTkachenko modes of vortex arrays in trapped BoseEinstein condensates Tapio Simula Kelvin waves are helical singlevortex displacement waves propagating in the direction of the vortex axis. Tkachenko waves are transverse shear waves of manyvortex arrays. These two types of normal modes represent certain limits of generic threedimensional vortexwaves. We have calculated the lowlying elementary excitation modes of fully threedimensional vortexarrays by solving the Bogoliubovde Gennes equations. [Preview Abstract] 

Q1.00184: Vortices in a BoseEinstein Condensate with Dipolar Interactions Zuleyha Oztas, Cem Yuce We study an offaxis vortex in a rotating BoseEinstein condensate with dipoledipole interactions in the ThomasFermi (TF) limit. We derive analytic results for small vortex displacements from the trap center and perform numerical calculations for large displacements. We prove that in an oblate trap the dipolar interaction energy increases as the vortex moves away from the trap centre contrary to the case in a prolate trap. We show that the dipolar interactions reduce (raise) the precision velocity of an offcenter straight vortex in an oblate (prolate) trap. We find that the angular velocity which is the onset of metastability is lowered in the presence of dipolar interactions in an oblate trap while it is raised in a prolate trap. [Preview Abstract] 

Q1.00185: Cascade Lshell soft xray emission as incident xray photons are tuned across 1s ionization threshold Dimosthenis Sokaras, Andrei Kochur, Matthias Mueller, Michael Kolbe, Burkhard Beckhoff, Michael Mantler, Charalambos Zarkadas, Miltiadis Andrianis, Anastasios Lagoyannis, AndreasGermanos Karydas The cascade Lshell xray emission as an incident polarized and unpolarized monochromatic radiation overpass the 1s ionization threshold is investigated for the metallic Fe by means of moderate resolution, quantitative xray spectrometry. A full \textit{ab initio} theoretical investigation of the Lshell xray emission processes is performed based on a detailed straightforward construction of the cascade decay trees within the PauliFock approximation. The agreement obtained between experiments and the presented theory is indicated and discussed with respect to the accuracy of advanced atomic models as well as its significance for the characterisation capabilities of XRay Fluorescence (XRF) analysis. [Preview Abstract] 

Q1.00186: Oscillations in dipoledipole transitions from nearly degenerate Rydberg states Donald P. Fahey, Michael W. Noel, Thomas J. Carroll Pairs of ultracold highly excited atoms can exchange energy over long distances through a dipoledipole coupling. We present an experimental study of the time dependence of this interaction. Rubidium atoms in a magnetooptical trap are impulsively excited to a coherent superposition of three closely spaced ($<$10 MHz) 32d$_{5/2}$ $m_{j}$ sublevels. An electric field is used to control the $m_{j}$ Stark splitting. Atoms are allowed to exchange energy according to 32d+32d$\rightarrow$34p+30f, and the distribution of final states is measured using state selective field ionization. As the time between excitation and ionization is varied, oscillations in the energy exchange are observed. The period of these oscillations is seen to decrease as the initial $m_{j}$ state separation is increased. [Preview Abstract] 

Q1.00187: Atomic strongfield physics using TDCIS Phay Ho We present an implementation of the timedependent configuration interaction singles (TDCIS) method for treating atomic strongfield processes. In order to remove the photoelectron wave packet at the end of the spatial grid, we add to the nonrelativistic manyelectron Hamiltonian a radial complex absorbing potential (CAP). We determine orbitals by diagonalizing the sum of the Fock operator and the CAP using a radial pseudospectral grid combined with spherical harmonics. Using the TDCIS wave packet, we examine electronic channelcoupling effects in strongfield ionization and highorder harmonic generation. We present three alternate forms highorder harmonic spectra, based on dipole moment, dipole velocity and dipole acceleration, for noble gas atoms. [Preview Abstract] 

Q1.00188: Calculation of He+H$_2$ crosssections using slow variable discretization enhanced renormalized Numerov propagator method Juan Blandon, Gregory Parker Collisional quenching is an important process in the trapping of diatomic molecules, which has attracted interest due to recent efforts to form molecular BoseEinstein condensates, for example. We apply the slow variable discretization enhanced renormalized Numerov method to calculate elastic and inelastic crosssections for the He+H$_2$ system, using the MuchnickRussek HeH$_2$ potential energy surface [1]. Such calculations are inherently technically difficult, due to the large number of H$_2$ bound states involved, and the large scattering energy range used in the calculations. \\[4pt] [1] P. Muchnick and A. Russek, J. Chem. Phys. {\bf100}, 4336 (1994). [Preview Abstract] 

Q1.00189: Toward a SteadyState Superradiant Light Source Joshua M. Weiner, Justin G. Bohnet, Zilong Chen, James K. Thompson We report on progress towards a continuous superradiant light source at 795~nm using $\sim10^6$ $^{87}$Rb atoms trapped in a low finesse (F = 710) optical cavity. Such a light source will probe the physics underlying recent proposals for milliHertz linewidth light sources that would revolutionize the precision of optical clocks and enable long baseline interferometry over earthtosun distances. In a superradiant light source, the time phase of a spontaneously generated polarization grating acts as the flywheel for phase information, in place of the intracavity light in a conventional laser. The linewidth of the generated light is predicted to fall well below both the SchawlowTownes limit for conventional lasers and the single particle decoherence rate. Importantly, the frequency of the emitted light is predicted to be highly insensitive to the thermal mirror motion that currently limits the narrowest of lasers. [Preview Abstract] 

Q1.00190: ThroughChip High Numerical Aperture Imaging of a BEC Evan A. Salim, Seth C. Caliga, Jonathan B. Pfeiffer, Dana Z. Anderson We present a chip based BEC apparatus that gives optical access to an atomic sample with numerical apertures as high as 0.8. We incorporate a window into a silicon chip that forms a wall of the vacuum chamber and makes it possible to place the primary objective of an imaging system as close as 600 microns from the atoms while the lens itself resides outside of the chamber. We show progress on our system, which allows for both highresolution intrap imaging of a BEC and projection of an optical potential in proximity of the chip surface with an offtheshelf microscope objective. The system is designed to enable atom tunneling experiments with the ultimate goal of demonstrating an atom transistor using a triplewell potential. [Preview Abstract] 

Q1.00191: Twocenter minima in harmonic spectra from aligned polar molecules Adam Etches, Mette B. Gaarde, Lars B. Madsen We extend a model of twocenter interference to include the superposition of opposite orientations in aligned polar molecules. We show that the position of the minimum in aligned CO depends strongly on the relative recombination strength at different atoms, not just the relative phase. Inclusion of the firstorder Stark effect shifts the position of the interference minimum in our numerical calculations, even though aligned molecules do not posses total permanent dipoles. Reinterpreting the minimum as an interference between opposite orientations, we explain the shift in terms of an extra phase that the continuum electron of oriented CO picks up due to the Stark effect. [Preview Abstract] 

Q1.00192: Monitoring quantum wavefunctions in the presence of dephasing noise Hermann Uys POVM measurements allow quantum state estimation in realtime with minimal disruption of the dynamics. Here we demonstrate that high fidelity state estimation is possible even in the presence of dephasing and amplitude noise by simulating such measurements on a twolevel system undergoing Rabi oscillations. Finite estimation fidelity persists long after the decoherence times set by the noise fields in the absence of measurements. [Preview Abstract] 
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