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 E1: Poster Session I (4:00 pm - 6:00 pm) |
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Room: Atrium Ballroom BC |
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E1.00001: COLD ATOMS, MOLECULES AND PLASMAS I |
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E1.00002: Rf excitation of an ultra-cold plasma Scott Galica, Duncan Tate In this presentation we will be discussing the results of our recent experiments exploring the effects of charge imbalance on radio-frequency (rf) absorption in ultra-cold neutral plasmas (UNPs). The UNP is created by photoionization of 100 $\mu$K Rb atoms in a MOT. The maximum electron density is $\sim10^9$ cm$^{-3}$, and the unperturbed plasma lifetime is approximately 150 $\mu$s. We have observed the change in electron evaporation rate when the UNP is excited with rf radiation in the range 10-270 MHz. We are analyzing our results using the theoretical approach proposed in a recent paper (Lyunbonko {\it et al.}, arXiv:1011.5937v1 [physics.plasm-ph]). Specifically, the theory addresses the response on a UNP with a gaussian density distribution as the rf frequency is changed, and considers the effect of the changing degree of charge imbalance as the UNP evolves. This issue is critical for understanding the experimental data, particularly since the maximum plasma resonant frequency also falls as the plasma expands. These factors result in a complex time-behavior of the electron evaporation rate. We are investigating the relationship between the charge imbalance and maximum plasma resonant frequency as functions of time, with the goal of obtaining information such as the electron density and plasma expansion velocity. [Preview Abstract] |
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E1.00003: Ultracold plasma apparatus with moving magnetic trap atom transfer Truman Wilson, Wei-Ting Chen, Jacob Roberts One of the challenges in creating and trapping ultracold plasmas is that the requirements for effective initial cooling and trapping of atoms in a Magneto-optic Trap (MOT) are not the same as those that requirements entailed in the desired design of electrodes and fields to conduct ultracold plasma experiments. We report on our development of an apparatus that uses moving magnetic trap coils, like those developed in Bose- Einstein condenstaion experiments, to transport atoms from a MOT to an ionization region where flexible electric and magnetic fields can be applied. [Preview Abstract] |
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E1.00004: Optical trapping and cooling of $^{87}$Rb with a 1550 nm fiber laser Abraham Olson, Ping Wang, Robert Niffenegger, Qianli Ma, Yong P. Chen We have investigated optical trapping and cooling of $^{87}$Rb with a 1550nm single-frequency, fiber laser. We present a technique to map out the 3D spatial intensity profile of an optical dipole trap by imaging a background, untrapped cold atomic cloud. The 1550nm laser causes a strong AC Stark shift [1] of the excited state (5P$_{3/2}$) of $^{87}$Rb which we image by driving the D2 transition. Such Stark tomography allows us to use an untrapped cloud of $^{87}$Rb to characterize the potential trap depth, beam waist, trapping frequency, beam quality factor (M$^{2}$), and astigmatism of the trap beam. We also investigated schemes for all- optical evaporative cooling of trapped atoms to quantum degeneracy. [Preview Abstract] |
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E1.00005: Characterization of the single atom optical trap Chung-Yu Shih, Michael Gibbons, Michael Chapman Individually trapped neutral atoms are promising candidate for quantum information processing. It is challenging to characterize the atom trapping environment and atom temperature for single atoms in contrast to many-atom traps. In this work, we are developing new techniques to accurately characterize these important quantities. [Preview Abstract] |
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E1.00006: Prospects for site-resolved imaging of ultracold fermions in optical lattices Florian Huber, Widagdo Setiawan, Katherine Wooley-Brown, Dylan Cotta, Markus Greiner Ultracold quantum gases in optical lattices are a perfect toy model to simulate condensed matter Hamiltonians. Recent success in imaging bosonic alkali atoms in-situ has enabled many new possibilities of studying such systems.\footnote{Gericke \textit{et al.}, \textit{Nature Physics} \textbf{4}, 949 (2008)}$^,$\footnote{Bakr \textit{et al.},\textit{Nature} \textbf{462}, 74 (2009)}$^,$\footnote{Sherson \textit{et al.}, \textit{Nature} \textbf{467},68 (2010)} By using fermionic species instead, a different class of Hamiltonians could be implemented, which are believed to exhibit new physics like d-wave superfluidity. We discuss the physical and technical challenges associated with the site-resolved imaging of fermionic alkali species, as well as our approach to detect single Lithium atoms using resonant two-photon ionization (UV+NIR) [Preview Abstract] |
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E1.00007: Non-destructive state measurement of individual neutral atoms Michael Gibbons, Chung-Yu Shih, Chris Hamley, Michael Chapman Non-destructive state detection of individual neutral atoms is essential for scalable neutral atom quantum information processing. We have demonstrated non-destructive fluorescent state detection of individual neutral atom qubits trapped in an optical lattice. The hyperfine state of the atom is measured with 95{\%} accuracy and the atom loss rate of 1{\%}. State detection is performed on individual atoms over 100 times before being lost from the trap, representing a~significant increase in the data collection rates. Using this technique, we have observed microwave Rabi oscillations with measurements done on one-and-the-same atom. [Preview Abstract] |
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E1.00008: Non-destructive imaging of sodium spinor Bose-Einstein condensates Eva Bookjans, Chandra Raman We report progress toward non-destructive, {\em in-situ} spatial imaging of spinor sodium Bose-Einstein condensates (BECs). Optically trapped samples containing between $10^6$ and $10^7$ condensed atoms are imaged. Due to its antiferromagnetic nature, the sodium spinor BEC possesses a nematic, rather than magnetic, order parameter. A novel imaging method can uncover the spatial dependence of this order, based upon detection of spin alignment rather than orientation. Our results have implications for dynamical studies of antiferromagnetic spinor gases, including the detection of novel topological defects. [Preview Abstract] |
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E1.00009: Equation of State for Quantum Hall Bosons in an Optical Lattice Eliot Kapit, Erich Mueller Using exact diagonalization and averaging over twisted boundary conditions, we calculate the finite temperature equation of state for a system of lattice bosons with hard core repulsion in an artificial magnetic field, and plot the resulting density profiles for trapped gases. We explore the temperature dependance of the fractional quantum Hall density plateaus, and give concrete bounds on the temperatures needed to see signatures of this physics in density profiles. Additionally, we explore the role of longer range hopping terms (cf. PRL 105, 215303). [Preview Abstract] |
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E1.00010: Emergent structure in a dipolar Bose gas in a one-dimensional lattice Ryan Wilson, John Bohn We consider an ultracold dipolar Bose gas in a one-dimensional lattice. For a sufficiently large lattice recoil energy, such a system becomes a series of non-overlapping Bose-Einstein condensates that interact via the long-range dipole-dipole interaction (ddi). We model this system via a coupled set of non-local Gross-Pitaevskii equations (GPEs) for lattices of both infinite and finite extent. We find significantly modified stability properties in the lattice due to the softening of a discrete roton-like mode, as well as ``islands'' in parameter space where biconcave densities are predicted to exist that only exist in the presence of the other condensates on the lattice. We solve for the elementary excitations of the system to check the dynamical stability of these solutions and to uncover the nature of their collapse. By solving a coupled set of GPEs exactly on a full numeric grid, we show that this emergent biconcave structure can be realized in a finite lattice with atomic $^{52}$Cr. [Preview Abstract] |
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E1.00011: Dynamics of ultracold molecules in confined geometry and electric field Goulven Qu\'em\'ener, John Bohn We present a time-independent quantum formalism to describe the dynamics of molecules with permanent electric dipole moments in a two-dimensional confined geometry such as a one-dimensional optical lattice, in the presence of an electric field [1]. Bose/Fermi statistics and selection rules play a crucial role in the dynamics. As examples, we compare the dynamics of confined fermionic and bosonic polar KRb molecules under different confinements and electric fields. We show how chemical reactions can be suppressed, either by a ``statistical suppression'' which applies for fermions at small electric fields and confinements, or by a ``potential energy suppression'', which applies for both fermions and bosons at high electric fields and confinements. Good agreement is found between our theoretical predictions and recent experimental results [2] of KRb molecules. \\[4pt] [1] G. Qu\'em\'ener and John L. Bohn, Phys. Rev. A 83, 012705 (2011). \\[0pt] [2] M. H. G. de Miranda, A. Chotia, B. Neyenhuis, D. Wang, G. Qu\'em\'ener, S. Ospelkaus, J. L. Bohn, J. Ye, D. S. Jin, to appear in Nature Physics, arXiv:1010.3731. [Preview Abstract] |
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E1.00012: Emulating Quantum Magnetism and t--J Models in Systems of Ultracold Polar Molecules S.R. Manmana, A.V. Gorshkov, E. Demler, M.D. Lukin, A.M. Rey In contrast to atomic systems, strong electric dipole-dipole interactions in systems of ultracold polar molecules open the way to directly emulate spin Hamiltonians at temperatures of the order of nK, realizable in current experiments. At unit filling of the lattice, this leads to $S=1/2$ XXZ-type of Hamiltonians, while below unit filling a highly tunable generalization of the $t-J$ model is obtained which we refer to as the $t-J-V-W$ model. In addition to the long-range dipolar interactions of XXZ type ($J_z$ and $J_\perp$) present at unit filling, density-density interactions $V$ and a novel density-spin interaction $W$ are obtained. These interaction terms can all be tuned independently of the tunneling $t$ in magnitude as well as in sign. The `spin' degrees of freedom are realized by addressing two rotational degrees of freedom of the molecules, while the interactions are controlled by applying static electric and continuous-wave microwave fields. Using the Density Matrix Renormalization Group method (DMRG) we obtain the phase diagram for the experimentally relevant case $J_z=V=W=0$ in 1D and find that superconductivity is enhanced compared to the usual $t-J$ model. [Preview Abstract] |
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E1.00013: Spectroscopic Determination of Optimal Pathways for Vibrational Transfer in Ultracold KRb Molecules J.T. Kim, Y. Lee, B. Kim, D. Wang, W.C. Stwalley, P.L. Gould, E.E. Eyler Many applications of ultracold polar molecules (quantum degeneracy, quantum information, and novel quantum phases) require molecules in their lowest rovibronic level.~ Formation of these molecules by photoassociation or magnetoassociation typically results in highly rovibronically excited molecules near dissociation.~ Stimulated Raman transfer is a promising method of converting these highly rovibronically excited molecules into the lowest rovibronic level, i.e. the $v$"=0, $J$"=0 level of the $X \quad ^{1}\Sigma ^{+ }$ ground electronic state.~ We show that a multiplicative combination of supersonic molecular beam spectra and ultracold polar molecule spectra can be used to determine the optimal pathways for Raman transfer for the specific example of KRb, even when spectral assignments are unavailable.~ Support from National Research Foundation of Korea, NSF and AFOSR is gracefully acknowledged. [Preview Abstract] |
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E1.00014: Loading of single atoms in an optical dipole trap using Rydberg blockade Xianli L. Zhang, Alex T. Gill, Larry Isenhower, Thad G. Walker, Mark Saffman Deterministic preparation of single atom occupancy in optical traps is an important prerequisite for implementation of neutral atom quantum computing. We present experimental progress towards that goal using Rydberg blockade interactions of cold Rb atoms. Starting with 5-15 atoms in an optical trap a sequence of optical pulses that implement Rydberg blockade dynamics is used to remove all but one of the atoms. We demonstrate single atom preparation with $> 55\%$ probability and discuss factors limiting the current performance. [Preview Abstract] |
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E1.00015: Bichromatic Force Slowing of Helium Over Large Velocity Ranges M.A. Chieda, E.E. Eyler The optical bichromatic force holds promise as an efficient, simple, and compact means to slow atoms to MOT capture velocities [1]. Metastable helium beams, with $v\sim1000$~m/s, are especially worthwhile candidates since they presently require Zeeman slowers with lengths of $2-3$~m. Two schemes for bichromatic slowing of helium atoms are considered: static and dynamic (or chirped). In the static slower, very highly detuned bichromatic beams with a fixed (static) Doppler shift are used. While the velocity range of the force is fundamentally capable of slowing the atoms to near rest in a single stage, there are several physical and engineering factors that limit the attainable upper range of the force, requiring a two-stage design. The dynamic slower employs beams with smaller bichromatic detunings in which the Doppler shifts are chirped in order to keep the force centered on the atoms as they are slowed. This is made possible by recent advances in high power diode lasers and electronics, and avoids many of the potential problems of the static slower. Experimental and theoretical results of both schemes will be presented, emphasizing the limitations and relative merits. \\[4pt] [1] M. Cashen and H. Metcalf, ``Optical forces on atoms in nonmonochromatic light,'' J. Opt. Soc. Am. B \textbf{20}, 915 (2003). [Preview Abstract] |
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E1.00016: Multi-photon sub-Doppler laser cooling Roger Brown, Saijun Wu, William Phillips, J. V. Porto Nearly all quantum gas experiments utilize magneto-optical trapping and subsequent sub-Doppler laser cooling stages. Following the demonstration of a multi-color multi-photon magneto-optical trap for Cesium [1], we study multi-photon sub-Doppler laser cooling in two configurations. In the first configuration, the ground to excited state coupling light is near resonant to the transition while the excited to further excited state coupling light is scanned over a wide range through two-photon resonance. In the second configuration, the ground to excited state coupling light is far red detuned from the transition while the excited to further excited state coupling light is scanned through two-photon resonance. In both cases, we observe sub-Doppler cooling which we attribute to a 2-color polarization gradient cooling mechanism. We support our observations with detailed numerical simulations. \\[4pt] [1] Wu et al. PRL 103, 173003 (2009) [Preview Abstract] |
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E1.00017: Laser Cooling and Trapping of Neutral Mercury Atoms Using an Optically-Pumped External-Cavity Semiconductor Laser Justin Paul, Christian Lytle, R. Jason Jones The level structure of the Hg atom is similar to other alkaline earth-like atoms, offering the possibility to realize an extremely high quality resonance factor (Q) on the ``clock'' transition ($^{1}$S$_{0}$- $^{3}$P$_{0})$ when confined in an optical lattice at the Stark-shift free wavelength. A key feature of the Hg system is the reduced uncertainty due to black-body induced Stark shifts, making it an interesting candidate as an optical frequency standard. One challenge to laser-cooling neutral Hg atoms is finding a reliable source for cooling on the $^{1}$S$_{0}-^{3}$P$_{1}$ transition at 253.7 nm. We employ an optically pumped semiconductor laser (OPSEL) operating at 1015 nm, whose frequency is quadrupled in two external-cavity doubling stages to generate over 120 mW at 253.7 nm. With this new laser source we have trapped Hg$^{199}$ from a background vapor in a standard MOT. We trap up to 2 x 10$^{6}$ atoms with a 1/e$^{2}$ radius of our MOT of $\sim $310 microns, corresponding to a density of 1.28 x 10$^{10}$ atoms/cm$^{3}$. We report on the progress of our Hg system and plans for precision lattice-based spectroscopy of the clock transition. [Preview Abstract] |
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E1.00018: Current tuning behavior of an extended-cavity diode laser: experiment and model Timothy Roach, Michael DeFeo, Andrew Novicki Grating stabilized extended-cavity diode lasers (ECDLs) are widely used for probing and manipulating atomic states, and can be tuned by grating adjustment, or at higher rates, by current tuning. A common and inexpensive design uses laser chips with uncoated facets, but interaction between the internal (chip) resonance modes and the extended cavity modes can result in mode hops when tuning by either method, or even unstable oscillation. This is well known generally to depend on the cavity dimensions, chip and grating reflectivities, and optical properties of the semiconductor. We have included these in a model of the laser oscillation of the ECDL system, and found that it reproduces well a range of tuning and mode hop behaviors observed in our experimental system, for a range of cavity lengths. For example, an observed repeating sequence of mode hops described by particular chip mode numbers {\{}m$_{0}$, m$_{1}$, m$_{2}$, m$_{0}$, m$_{1}$, m$_{2}$, etc.{\}} can result from a particular frequency spacing of external modes compared to chip modes. We are presently investigating how the model might be used to improve laser stability and RF modulation characteristics of ECDL systems. [Preview Abstract] |
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E1.00019: Generalized Gradient Approximation for trapped ultracold atoms in optical lattices James Freericks, Karlis Mikelsons, Hulikal Krishnamurthy We present results of both quantum Monte Carlo calculations and exact analytic theories that employ corrections to the local density approximation for simulating realistic sized lattices (few million lattice sites, hundreds of thousands of particles). The QMC uses a continuous time impurity solver for inhomogeneous dynamical mean field theory. Applied to the Hubbard model, we analyze the relationship between the entropy and double occupancy for the experimental data on K$^{40}$ measured by the ETH group. We also present results on mixtures of light and heavy atoms which are described by the Falicov-Kimball model. We find that both the LDA and the GGA work very well above the temperature where the homogeneous system first sees ordering. They can accurately correct approximations like the strong-coupling perturbation theory at low temperature, or for weak coupling, but the computational cost is dramatically higher. We also summarize how to go beyond the GGA to a full IDMFT implementation on large lattices using sparse matrix techniques. [Preview Abstract] |
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E1.00020: Resolving Momentum and Position in a trapped gas using Laguerre-Gaussian beams Rabin Paudel, Tara Drake, John Gaebler, Jayson Stewart, Deborah Jin We demonstrate a general method to probe the momentum distribution of ultracold atoms near the center of a trap, thereby removing the effect of atoms at low density near the trap edge. Our basic technique is to use two intersecting Laguerre-Gaussian beams to selectively remove atoms from the edge of the cloud before releasing the trapped gas for time-of-flight expansion. This allows us to observe a sharp Fermi surface of a degenerate $^{40}$K atom cloud. We then apply the technique to atom photoemission spectroscopy to probe the effect of density inhomogeneity on this measurement technique in the BCS-BEC crossover. [Preview Abstract] |
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E1.00021: Universal Quantum Viscosity in a Unitary Fermi Gas Chenglin Cao, Ethan Elliott, Haibin Wu, John Thomas We measure the shear viscosity in a two-component Fermi gas of atoms, tuned to a broad s-wave Feshbach resonance. At resonance, the atoms strongly interact and exhibit universal behavior, where the equilibrium thermodynamic properties and the transport coefficients are universal functions of the density $n$ and temperature $T$. By properly including both the friction force and the heating rate in the universal hydrodynamic equations, we determine the shear viscosity in units of $\hbar\,n$ as a function of the reduced temperature at the trap center from nearly the ground state to the unitary two-body regime. The temperature of our strongly interacting Fermi gas is calibrated by using a smooth power law curve to fit the energy versus entropy curve, for which $T=\partial E/\partial S$ determines the temperature. The measured trap-averaged entropy per particle and shear viscosity are used to estimate the ratio of the shear viscosity to the entropy density, which is compared to that of a perfect fluid. [Preview Abstract] |
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E1.00022: Molecular condensate fraction of two-component few-fermion systems under harmonic confinement K.M. Daily, D. Blume Using a non-perturbative stochastic variational approach, we perform a bottom-up investigation of non-local properties of harmonically trapped equal-mass s-wave interacting two-component few-fermion systems [1]. For small but positive interspecies s-wave scattering lengths $a_s$, pairs of opposite spin fermions form tightly bound bosonic dimers that condense to form a molecular Bose-Einsten condensate. We propose a measure of the molecular condensate fraction based on the two-body density matrix and apply this measure to systems with up to six particles. Furthermore, we calculate the spherical component of the momentum distribution associated with the center of mass of pairs of fermions. This momentum distribution develops a double peak structure as the scattering length decreases from large positive to small positive values. Our numerical results are confirmed analytically. In particular, our analytical expressions reproduce the numerical results with high accuracy and, furthermore, provide a clear interpretation of the double peak structure of the momentum distribution.\\[4pt] [1] D. Blume and K. M. Daily, Comptes Rendus Physique, in press (2011). [Preview Abstract] |
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E1.00023: Phase diagram of a population-imbalanced attractive Fermi gas in the 1D-3D crossover regime Satyan Bhongale, Leslie Baksmaty, Han Pu Phase diagram of a population imbalanced attractive Fermi gas in the 1D-3D dimensional crossover regime is obtained via deriving a multi-channel inter-atomic scattering pseudopotential. Such a phase diagram has strong implications for the observation of FFLO superfluidity within trapped fermions. Recent experiment with ultra-cold Li6 have mapped the phase diagram for 1D attractive fermions [Nature 467, 567 (2010)], however the superfluid property is yet to be confirmed. While the signature of FFLO in 1D is predicted to coincide with micro-phase separated domains, the feasibility of direct experimental identification of the domain walls remains questionable due to strong fluctuations. On the other hand, in 3D, fluctuations may be neglected, but the FFLO corresponds to just a tiny sliver of the phase diagram. Moreover, the topology of the phase diagram is drastically different in the two extreme dimensional limits. We show how the 1D and 3D dimensional limits are connected and indicate the possible new physics in the crossover regime. [Preview Abstract] |
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E1.00024: Trapping Rb atoms and dimmers in a broadband optical dipole trap Bruno Marangoni, Carlos Menegatti, Luis Marcassa Several experiments involving cold homonuclear and heteronuclear molecules rely on the photoassociation of trapped atoms. In order to obtain a large molecular sample, it is necessary to start from a dense atomic sample. In our experiment, we are trapping cold Rb atoms and Rb$_{2}$ molecules in a crossed broadband optical dipole trap. Our crossed beam configuration uses 25 W (at 1064 n, bandwidth of 2 nm) in each in each of the beams with about 50 micron waist radius of the focus and a depth of about 760 $\mu $K. Our results suggest that photoassociation of the trapped atoms due to 1064 nm laser is taking place. We have also developed a technique using a train of laser pulses to observe the time evolution of Rb$_{2}$ molecules. This train of laser pulses photoionize the Rb$_{2}$ molecules trough resonant two-photon ionization. Such technique is implemented in such way that allows us to continuously observe the molecular sample. Therefore, it allows a faster data acquisition. [Preview Abstract] |
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E1.00025: Collisions of matter waves with ultracold atoms in a ring trap Manuel Valiente, Nicolai Nygaard, Klaus Molmer Ultracold atoms confined in ring-shaped potentials constitute a neat experimental realization of finite-size one-dimensional many-body systems. Usually, these potentials are modeled by traps, which do not support a continuum of states. We consider here fermionic or bosonic atoms trapped in thin ring potentials supporting a finite number of bound states, and scattering states, and probe their behavior via collisions of matter waves. [Preview Abstract] |
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E1.00026: Multichannel quantum-defect theory of magnetic Feshbach resonances in heteroneuclear alkali-metal systems Constantinos Makrides, Bo Gao We present a multichannel quantum-defect theory for the magnetic Feshbach resonances in the interaction of two heteroneuclear alkali-metal atoms. The emphasis will be on resonances in nonzero partial waves, and their parametrization that has only recently been developed\footnote{B. Gao, Phys. Rev. A \textbf {80}, 012702 (2009).}. The theory will be illustrated with sample results for selected alkali-metal systems that include LiK. [Preview Abstract] |
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E1.00027: Quantum-defect theory of resonant charge exchange Ming Li, Bo Gao We apply the quantum-defect theory for $-1/r^4$ potential\footnote{B. Gao, Phys. Rev. Lett. \textbf{104}, 213201 (2010).} to study the resonant charge exchange process. We show that by taking advantage of the angular-momentum- insensitive nature of formulation, resonant charge exchange of the type of $^1S$+$^2S$ can be accurately described over a wide range of energies using only three parameters, such as the gerade and the ungerade scattering lengths, and the atomic polarizability. The parameters can be determined experimentally, without having to rely on accurate potential energy surfaces (PES), of which few exist for ion-atom systems. The theory further relates ultracold interaction to interactions at much higher temperatures. [Preview Abstract] |
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E1.00028: Feshbach resonance enhanced photoassociation (FREPA) spectroscopy of Rb$_2$ James Dizikes, Thomas Akin, Sean Krzyzewski, Michael Morrison, Eric Abraham Ultracold photoassociation spectroscopy has been used to measure binding energies of near-dissociation, excited alkali dimers, which increases the precision with which atomic and molecular information is known. It is also an indispensable tool in the study of Feshbach resonances and in their use in producing ultracold molecules. We will discuss calculations and simulations for using Feshbach resonances to enhance photoassociation into previously unattainable excited molecular states and the possibility of improving our knowledge of the interatomic interaction. Initial work will focus on the $0^-_g$ state of Rb$_2$ that connects asymptotically to the $5^2S_{1/2} + 5^2P_{1/2}$ separated atom limit. Progress toward the experimental realization of FREPA will be presented. [Preview Abstract] |
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E1.00029: Formation of Be$_2^+$ molecules in the metastable B$^2\Sigma_g^+$ state by ultracold photoassociation Sandipan Banerjee, Jason Byrd, Robin C\^ot\'e, H Michels, John Montgomery We suggest a photoassociation (PA) scheme to form ultracold Be$_2^+$ molecules in the long-range outer well of the B$^2\Sigma_g^+$ state. In our previous work \footnote{S. Banerjee \textit{et al.} Chem. Phys. Lett. 496 (2010) 208.}, we have calculated the ground states of Be$_2^+$ dimer and have analyzed in detail the double well nature of the B$^2\Sigma_g^+$ state. We also note that the vibrational levels in the outer well of the B$^2\Sigma_g^+$ state have significantly longer radiative lifetimes ($\sim$ ms) than the ones in the inner well ($\sim$ $\mu$s). Using similar \textit{ab initio} methods (valence full CI), we have now calculated the excited $^2\Pi_{u/g}$ and $^2\Sigma_{u/g}$ states. For the proposed PA scheme, we populate the A$^2\Pi_u$ state and radiatively decay into the B$^2\Sigma_g^+$ state of Be$_2^+$. We also calculate transition dipole moment, Frank-Condon factors between the A$^2\Pi_u$ and B$^2\Sigma_g^+$ states. [Preview Abstract] |
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E1.00030: Prospects for photoassociation of alkaline-earth-alkali-metal neutral and ionic molecules Olivier Dulieu, Mireille Aymar, Nadia Bouloufa, Romain Guerout In this work, we investigate the previously unknown electronic structure and properties of ionic and neutral diatomic molecules which could be formed from cold Strontium ions or atoms and ultracold alkali atoms A (A=Li, Na, K, Rb, Cs). The ionic and neutral species can be modeled as effective two- and three-valence electron systems respectively, in the field of polarizable ionic cores Sr+ and A+. Using a standard quantum chemistry approach based on pseudopotentials for atomic core representation, Gaussian basis sets, effective core polarization potentials, and full configuration interaction (FCI) we calculate potential curves, permanent and transition dipole moments, and static dipole polarizabilities for several molecular states of various symmetries as functions of the internuclear distance. The possibilities for radiative charge exchange, photoassociation, and formation of cold molecular ions, and photoassociation and formation of cold neutral molecules, are discussed, as well as the collisional stability of the molecular species in the presence of remaining atoms. [Preview Abstract] |
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E1.00031: Relative number squeezing in a spin-1 Bose-Einstein condensate Eva Bookjans, Chris D. Hamley, Michael S. Chapman The quantum properties of matter waves, in particular quantum correlations and entanglement are an important frontier in atom optics with applications in quantum metrology and quantum information. We will report on the observation of sub- Poissonian fluctuations in the magnetization of a spinor $^{87} $Rb condensate. The fluctuations in the magnetization are reduced up to 10~dB below the classical shot noise limit. This relative number squeezing is indicative of the predicted pair- correlations in a spinor condensate and lay the foundation for future experiments involving spin-squeezing and entanglement measurements. We have investigated the limits of the imaging techniques used in our lab, absorption and fluorescence imaging, and have developed the capability to measure atoms numbers with an uncertainly $<$~10 atoms. Condensates as small as $\approx$~10 atoms were imaged and the measured fluctuations agree well with the theoretical predictions. [Preview Abstract] |
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E1.00032: Splitting dynamics of a two-species Bose-Einstein condensate in two translating traps Bo Sun, M.S. Pindzola We simulated the splitting dynamics of a two-species condensate in two translating traps. Different from the single species case, we find that the splitting is not 50:50 towards small translation speed for both species. We interpret this as a result of the effective potential induced by the mean field inter-species interaction. Such a picture is valid for both positive and moderate negative inter-species scattering lengths. From our numerical results, it turns out that the two-species condensate beam splitter is less controllable than the single species case. The performance of our dual species atomic beam splitter is supported by exploring realistic physical parameters. [Preview Abstract] |
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E1.00033: Imaging the 3D structure of vortex cores in Bose-Einstein condensates Kali Wilson, E. Carlo Samson, Zachary Newman, Brian P. Anderson We describe an absorption imaging technique that enables the determination of the three-dimensional structure of vortex cores in Bose-Einstein condensates. In our procedure, spherical or oblate BECs are created in a magnetic trap, and various excitation techniques can be used to generate vortices in the condensate. The condensate is then released from the trap, and multiple absorption images are taken of the ballistically expanding condensate. These images are stitched together to form a single 3D image. This technique allows for studies of vortex structure and dynamics in experiments where the vortex cores are not aligned with a single imaging axis. [Preview Abstract] |
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E1.00034: Generating sodium Bose-Einstein condensates in hybrid magnetic quadrupole and optical traps Jie Jiang, Zongkai Tian, Alex Behlen, Jared Austin, John Jepson, Yingmei Liu We present the design and construction of a novel apparatus to rapidly and simply generate $^{23}$Na Bose-Einstein condensates in hybrid magnetic and optical traps. Sodium atoms are collected in a magnetic-optical trap, captured in a magnetic quadrupole trap, and then cooled through forced radio-frequency evaporation. To avoid Majorana spin-flip losses at the center of the magnetic quadrupole trap, the cold dense atomic cloud is transferred to a crossed red-detuned optical dipole trap. By reducing the optical trap depth, sodium Bose-Einstein condensates are generated from forced evaporation and rethermalization in the crossed optical trap. This hybrid approach combines the advantages of both magnetic quadrupole and optical traps. [Preview Abstract] |
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E1.00035: A new approach to number-conserving Bogoliubov approximation for Bose-Einstein condensates Zhang Jiang, Carlton Caves We consider a BEC of $N$ ultra-cold atoms in a trapping potential. The many-body wave function of the BEC is ``encoded" in the $N$-particle sector of an extended catalytic state, coherent state for the condensate mode and a state for the orthogonal modes. Using a time-dependent interaction picture, we move the coherent state to the vacuum, where all the field operators are small compared to ${N}^{1/2}$. The resulting Hamiltonian can then be organized by powers of ${N}^{-1/2}$. Requiring the terms of order ${N}^{1/2}$ to vanish, we get the GP equation for the condensate wave function. Going to the next order, $N^0$, we are able to derive equations equivalent to those found by Castin and Dum [Phys. Rev. A \textbf{57}, 3008 (1998)] for a number-conserving Bogoliubov approximation. In contrast to other approaches, ours allows one to calculate the state evolution in the Schr\"{o}dinger picture, and it also has advantages in discussing higher-order corrections and multi-component cases. [Preview Abstract] |
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E1.00036: 2D analysis of shock waves in a unitary Fermi-gas James Joseph We study the nonlinear hydrodynamics of a strongly interacting Fermi gas comprising a 50-50 mixture of the lowest two hyperfine states of $^6$Li near a broad Feshbach resonance at 834 G. The gas is is cooled via forced evaporation in a cigar-shaped CO$_2$ laser trap with a repulsive optical sheet potential at the center creating two separate clouds. When the repulsive potential is turned off and the two clouds collide we observe exotic nonlinear hydrodynamics distinguished by the formation of a very sharp and stable density peak at the center of the trap and subsequent evolution into a box-like shape with sharp edges. Taking advantage of the laser trap's cylindrical symmetry, we solve the zero temperature hydrodynamic equations numerically in two dimensions. As a result, the numerical simulation provides the three dimensional density and velocity fields. We fit the density field to our experimental data using shear viscosity as our only fitting parameter. Further, we use the density and velocity fields provided by the simulation to calculate the total mechanical energy of the atoms. [Preview Abstract] |
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E1.00037: Dynamics and evaporation of defects in Mott clusters Dominik Muth, David Petrosyan, Michael Fleischhauer Strongly interacting pairs of atoms in a lattice can form tighly bound dimers [1]. In turn, such dimers interact with each other via attractive nearest-neighbor interaction mediated by virtual (second order) hopping [2]. In the case of bosons, the dimers can form a stable, incompressible cluster corresponding to a finite-size Mott insulator. Unpaired bosons in such a cluster represent highly mobile defects. We study the dynamics of these defects in 1D clusters using analytical techniques and t-DMRG simulations. We discuss how the quasi-thermalization of the defects mediated by their collisions, followed by evaporation through the boundary of the cluster, can purify the Mott insulator. [Preview Abstract] |
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E1.00038: Pseudospin and spin-spin interactions in ultra-cold alkali atoms D.H. Santamore, Eddy Timmermans Ultra-cold alkali atoms trapped in two distinct hyperfine states in an external magnetic field can mimic magnetic systems of spin-1/2 particles, therefore, the spin-dependent effective interaction can be described as a spin-spin interaction. We present the short-range, effective pseudospin-spin interaction potential that describes s-wave interactions of ultra-cold atoms that occupy a superposition of two hyperfine states in an external magnetic field. The interaction of spin1/2 bosons can be described as either a short-range Ising spin-spin coupling or an XY-coupling. Our work illustrates the advantage of the spin-spin interaction form by mapping the system of N spin-1/2 bosons confined by a tight trapping potential on that of N spin-1/2 spins coupled via an infinite range interaction. We also show the advantage of the spin-spin interaction description by deriving the many-spin Hamiltonian of N boson particles contained in a tightly confining trap. This system, a controllable quantum magnet, is a promising system to probe macroscopic quantum tunneling, realize spin squeezing and Heisenberg-limited interferometry. [Preview Abstract] |
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E1.00039: Self-Trapping dynamics in a 2D optical lattice Shuming Li, Aaron Reinhard, Jean-Felix Riou, Laura Adams, Rafael Hipolito, Anatoli Polkovnikov, David Weiss, Ana Rey We present a variational mean field model used to characterize our recent experiments on the expansion dynamics of an ultra cold gas of $^{87}$Rb atoms initially trapped in a two dimensional optical lattice. The expansion is driven by suddenly turning off the harmonic confinement potentials in all directions. \textit{In situ} measurements of the density profile vs time were performed for different lattice depths. The observed dynamics are characterized by an initial suppression of the transverse dynamics, followed by a ballistic expansion across the lattice after the initial interaction energy is converted into kinetic energy along the free expanding axial direction. The slow initial expansion is predicted to be a manifestation of macroscopic self-trapping. We present comparisons between our variational model and the measured profiles. [Preview Abstract] |
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E1.00040: Quantum pumping with ultracold atoms M. Ivory, K. Das, T. Byrd, K. Mitchell, J. Delos, S. Aubin Quantum pumping is a mechanism for generating a very precise, bias-less flow of electrons between two reservoirs by applying a local pumping potential. However, previous quantum pumping experiments have been unsuccessful due to competing capacitive coupling and rectification effects in solid state systems. Ultracold atoms offer the possibility of bypassing these difficulties and testing previously unverified theoretical predictions.~ We present numerical simulations to identify experimental parameters which are capable of yielding large currents using time-varying pumping schemes. Our simulations are both quantum and classical in nature and explore double barrier and double well turnstile pumps with rectangular and Gaussian potentials. We show that for a specific momentum classes, there is significant pumping. Also, due to multiple reflections between the barriers in the classical case, some particles show significant dependence upon initial conditions suggestive of fractal behavior. We present preliminary theoretical results for various schemes and suggest parameters for ultracold atom experiments. [Preview Abstract] |
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E1.00041: Pairing, ferromagnetism, and condensation of a normal spin-1 Bose gas Stefan Natu, Erich Mueller We theoretically study the stability of a normal, spin disordered, homogenous spin-$1$ Bose gas against ferromagnetism, pairing, and condensation through a Random Phase Approximation which includes exchange (RPA-X). Repulsive spin-independent interactions stabilize the normal state against both ferromagnetism and pairing, and for typical interaction strengths leads to a direct transition from an unordered normal state to a fully ordered single particle condensate. Atoms with much larger spin-dependent interaction may experience a transition to a ferromagnetic normal state or a paired superfluid, but, within the RPA-X, there is no instability towards a normal state with spontaneous nematic order. We analyze the role of the quadratic Zeeman effect and finite system size. [Preview Abstract] |
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E1.00042: A Nanoplasmonic Lattice for Quantum Simulation with Cold Atoms Michael Gullans, Darrick Chang, Tobias Tiecke, Jeff Thompson, Ignacio Cirac, Peter Zoller, Mikhail Lukin Optical lattices formed from interfering laser beams are a powerful tool for quantum simulation with cold atoms. However, this approach faces limitations in achieving low enough temperatures to observe many proposed strongly-correlated states. We discuss a scheme for generating an optical lattice by illuminating a two- dimensional array of metallic nanospheres near their surface plasmon resonance. The lattice spacing is set by the spacing between adjacent spheres and can be much smaller than a wavelength for small enough spheres. We describe an adiabatic loading procedure starting from a Bose-Einstein condensate. We estimate the trap lifetime including the van der Waals attraction with the sphere. We discuss two applications of this system to quantum simulation. First, the subwavelength lattice spacing and trapping pushes the optical lattice dynamics into a new range of energy scales for the Hubbard model by as much as two orders of magnitude compared to traditional optical lattices. Second, subwavelength separations result in strong radiative coupling between atoms and nanoparticles. This strong coupling can be used to engineer long range interactions between atoms that are dissipative by nature; thereby allowing the system to be driven into correlated many-body states in steady state. [Preview Abstract] |
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E1.00043: Trapped few-particle systems with finite angular momentum: Results obtained using the stochastic variational approch D. Rakshit, D. Blume Trapped few-boson and few-fermion systems are ideally suited to study few-body phenomena. A particularly exciting topic along these lines is the three-body Efimov effect and its implication and generalization to larger systems. We present a theoretical approach that allows for the characterization of small ultracold systems with up to five or six particles. The ground states of the three- and four-boson systems under external spherically-symmetric harmonic confinement have vanishing orbital angular momentum. The ground states of two-component Fermi systems with population difference, in contrast, have finite angular momentum L. For example, the ground states of the non-interacting (2,1) and (3,1) systems carry one unit of angular momentum and have natural and unnatural parity, respectively. We apply the stochastic variational approach to two-component Fermi gases with finite angular momentum. We discuss our implementation and present results for the energies as a function of the system parameters such as the s-wave scattering length and the mass ratio between the two species. [Preview Abstract] |
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E1.00044: Feshbach molecule creation in a Bose-Fermi (40K-87Rb) mixture Ming-Guang Hu, Tyler Cumby, Ruth Shewmon, Deborah Jin In an ultracold atom gas, a sweep of a magnetic field across a Fano-Feshbach resonance can associate pairs of atoms into weakly bound molecules. For an ultracold 40K-87Rb mixture, we observe that this association efficiency (the number of observed molecules divided by the number of possible pairs) for adiabatic sweeps is significantly lower than the prediction of a phenomenological model that was developed in conjunction with single-species experiments [Ref.E.Hodby,et al.(2005).PRL 94 120402]. We will report on investigation of this magneto-association process in the 87Rb-40K gas. [Preview Abstract] |
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E1.00045: Two- and Three-body dipolar physics: Efimov physics for interacting dipoles Jose P. D'Incao, Yujun Wang, Chris H. Greene We have developed an adiabatic representation for the two- and three-dipole problems and identified key properties of such systems which might have impact on current experiments with ultracold dipolar atomic and molecular gases. On the two-body level we have explored the three dimensional (3D) and quasi-two-dimensional (Q2D) cases and found that the usually broad dipole-dipole resonances in 3D become extremely narrow in Q2D, limiting the prospects of the control of the dipolar interaction. We also propose an energy analytic form for the pseudo potentials for dipoles that can offer an alternative way to explore the many-body behavior of dipolar gases. On the three-body level, we have found that the effect of the dipolar interactions is quite beneficial to the study of Efimov physics. For dipolar systems, the Efimov physics becomes universal in the sense that it only depends on the two-body physics and besides that the Efimov states tend to be have longer lifetimes as the dipolar interaction becomes increasingly stronger. This work was supported by the US-AFOSR-MURI and NSF. [Preview Abstract] |
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E1.00046: Probing ultracold Bose-Fermi mixtures in optical lattices Jannes Heinze, S{\"o}ren G{\"o}tze, Jasper Simon Krauser, Bastian Hundt, Nick Fl{\"a}schner, Dirk-S{\"o}ren L{\"u}hmann, Christoph Becker, Klaus Sengstock Quantum gases in optical lattices offer a wide range of applications for quantum simulation due to fully tunable lattice and atomic interaction parameters. In particular the use of particles with different statistics provides novel possibilities compared to conventional solid state systems. In this poster we report on high resolution spectroscopy of both ultracold bosons and fermions in optical lattices. The band structure is extracted fully momentum resolved [1] and interacting and non-interacting systems are compared. In addition, we are able to identify different excitations, such as the recently proposed amplitude mode in strongly correlated bosonic systems by comparing the data with numerical calculations [2]. This includes systematic shifts of the resonances, e.g. due to beyond linear response effects and the underlying harmonic confinement. [1] P. T. Ernst et al., Probing superfluids in optical lattices by momentum-resolved Bragg spectroscopy, Nature Physics 6, 56 - 61 (2010) (DOI: 10.1038/nphys1476); [2] U. Bissbort et al., Detecting the Amplitude Mode of Strongly Interacting Lattice Bosons by Bragg Scattering, arXiv:1010.2205 [Preview Abstract] |
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E1.00047: Quantum simulation of frustrated magnetism in a triangular optical lattice Julian Struck, Christoph \"Olschl\"ager, Christina Staarmann, Parvis Soltan-Panahi, Dirk-S\"oren L\"uhmann, Rodolphe Le Targat, Patrick Windpassinger, Klaus Sengstock We present the experimental realization of a quantum simulator for magnetism with ultracold quantum gases in optical lattices. It is possible to emulate magnetic interactions of a xy-model - with spinless bosons - by identifying the local superfluid phase on each lattice site with a classical spin. Applying a time periodic acceleration to the lattice allows for tuning independently the tunneling matrix elements between neighboring lattice sites in magnitude and sign. We have mapped out all relevant parts of the phase diagram and could observe several different phases, ranging from ferromagnetic via parallel- and staggered-spin-chains to fully antiferromagnetic systems. In the latter case, we observed spin frustration which leads to a two-fold degenerate ground-state. Here we observe the symmetry breaking spontaneous occupation of one ground-state. Furthermore we will discuss the possibility to study quenching dynamics between different phases and to explore the quantum xy-model which should exhibit spin-liquid phases in case of the triangular lattice. [Preview Abstract] |
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E1.00048: Ordered states and Mott states of three-component fermionic atoms in optical lattices at finite temperatures Sei-ichiro Suga, Kensuke Inaba We systematically investigate the properties of three-component (color) fermionic atoms in optical lattices using a two-site dynamical mean field theory and a self-energy functional approach. For the attractively interacting systems, we obtain the finite-temperature phase diagram for the color superfluid (CSF), trionic state, and Fermi liquid [1]. We find that as the anisotropy of the attractive interactions increases, the CSF region extends owing to the suppression of the trion formation. We also investigate the repulsively interacting system. We show that even at incommensurate filling the Mott transition occurs for the anisotropic interactions and that two kinds of Mott states appear, which are characteristic of the three-component systems [2]. The finite-temperature phase diagram is also determined. We demonstrate that such exotic Mott states can be detected in experiments by, e.g., the photoassociation loss measurements.\\[4pt] [1] K. Inaba and S. Suga, \textit{Phys. Rev. A} \textbf{80}, 041602(R) (2009).\\[0pt] [2] S. Miyatake, \textit{et al}., \textit{Phys. Rev. A} \textbf{81}, 021603(R) (2010); K. Inaba, \textit{et al.}, \textit{ibid.} \textbf{82}, 051602(R) (2010). [Preview Abstract] |
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E1.00049: Observing precursors of the Dicke quantum phase transition Rafael Mottl, Ferdinand Brennecke, Kristian Baumann, Tobias Donner, Tilman Esslinger A Bose-Einstein condensate coupled to an optical high-finesse cavity realizes an effective version of the Dicke Hamiltonian. This model was predicted to show an intriguing quantum phase transition. In our experiment, a transverse pump field couples collective density waves of the condensate to the cavity light field. By controlling the transverse pump power, the system is driven from the normal to the super-radiant phase. We investigated the excitation spectrum of the coupled system in the normal phase by Bragg spectroscopy and identified a collective density mode which softens at the transition point. This vanishing energy scale significantly alters the spectrum of atomic density fluctuations: the barrier to incoherently populate the soft mode is continuously reduced. The openness of the cavity allows to extract in-situ information about the fluctuations of the system from the photons leaving the cavity. We could reveal increased noise at the frequency of the soft mode by analyzing time-correlations between the leaking cavity photons. [Preview Abstract] |
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E1.00050: Fermi-Hubbard physics with ultracold fermions in optical lattices Thomas Uehlinger, Daniel Greif, Gregor Jotzu, Leticia Tarruell, Tilman Esslinger The Fermi-Hubbard Hamiltonian is one of the key models for strongly correlated electrons in solid state systems and incorporates fascinating phenomena such as Mott insulating behavior and spin ordered phases. Despite intense numerical effort, a number of questions still remains open, in particular on the low temperature phases where spin degrees of freedom start to play a role. In our experiment we use a two-component Fermi gas loaded into an optical lattice to realize this simple model Hamiltonian. Currently several experiments are reaching out to access the regime of quantum magnetism. We report on recent progress of creation and characterization of low entropy states in the lattice. [Preview Abstract] |
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E1.00051: Heterodimer of Two Distinguishable Atoms in a One-dimensional Optical Lattice Otim Odong, Jerome Sanders, Juha Javanainen Within the Bose-Hubbard model, we theoretically analyze the stationary states of two distinguishable atoms in a one-dimensional optical lattice. A partial separation of the center-of-mass motion and the relative motion of the two atoms is used to determine the eigenstates in a finite lattice. These states are then analyzed in the limit of an infinitely long lattice. We highlight the differences between the results for two distinguishable atoms and two identical atoms. One interesting example is that if the lattice parameters are modulated, the dimer may dissociate into a channel in which there is no atom-atom interaction. [Preview Abstract] |
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E1.00052: Molecular metrology based on ultracold alkaline-earth atoms in optical lattices Chris Osborn, Gael Reinaudi, Klejda Bega, Tanya Zelevinsky Diatomic molecules at ultracold temperatures offer novel possibilities for precision measurement, studies of many-body physics, and quantum control. Two-electron-atom based molecules in optical lattices are promising for precision experiments such as vibrational frequency metrology and constraining variations of the proton-electron mass ratio. We discuss progress toward a molecular clock, including forbidden-line molecular photoassociation in various lattice configurations. [Preview Abstract] |
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E1.00053: Progress toward scalable quantum information processing using $^{6}$Li and $^{133}$Cs atoms Arjun Sharma, Nathan Gemelke, Shih-Kuang Tung, Cheng Chin We present our progress on the construction of a novel, scalable quantum information processing system. The system consists of both fermionic $^6$Li and bosonic $^{133}$Cs atoms. The two species are simultaneously and independently trapped in two separate optical lattices. $^6$Li atoms are cooled into a degenerate band-insulator state that will allow uniform loading of one atom per site. These $^6$Li atoms serve as quantum bits (qubits). $^{133}$Cs atoms have a lower filling of one atom per 100 sites and will serve as messengers to induce entanglement among the qubits. In order to implement collision-based entangling operations, our plan for initial studies include the interspecies collision properties of $^{133}$Cs-$^6$Li at a magnetic field of up to 1000G, and the control of atoms on the single-atom level in two-color optical lattices. [Preview Abstract] |
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E1.00054: Phase coherence properties of two-component BECs under localizing mean-field lattices with an optical lattice Hyunoo Shim, Thomas Bergeman A binary mixture of interacting Bose Einstein Condensates (BEC) forms interdependent localizing mean-field lattices in the presence of a localization-driving external lattice potential. An equilibrium state exists in the balance between the mean-field dynamic lattices and the external static lattice. We show loss of phase coherence in an unequal mixture of two-component BECs in a gradual ramp of a state-selective optical lattice, and we study effects of localizing mean-field lattices on coherence loss under various states. Numerical calculations are performed for mean-fields with quantum and thermal fluctuations via several phase space representations including the Truncated Wigner Approximation (TWA) and a TWA-positive P hybrid representation, and the comparison of results from these two approaches is also presented. [Preview Abstract] |
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E1.00055: ATOMIC AND MOLECULAR STRUCTURE AND PROPERTIES |
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E1.00056: Experimental Studies of the NaCs $5^3\Pi_0$, $4^3\Pi_0$, and $1(a)^3\Sigma^+$ States Carl Faust, Joshua Jones, Seth Ashman, Christopher Wolfe, Marcellus Parker, Kara Richter, Brett McGeehan, Peet Hickman, John Huennekens We present experimental studies of the NaCs molecule that are currently underway in our laboratory. The optical-optical double resonance method is used to obtain Doppler-free excitation spectra for several excited states. Selected data from the $5^3\Pi_0$ and $4^3\Pi_0$ electronic states are used to obtain Rydberg-Klein-Rees (RKR) and Inverse Perturbation Approach (IPA) potential curves. We have also mapped the repulsive wall of the $1(a)^3\Sigma^+$ potential using many resolved bound-free fluorescence spectra from individual ro-vibrational levels of the $5^3\Pi_0$ electronic state to the $1(a)^3\Sigma^+$ state. Using the determined $5^3\Pi_0$ state potential, we fit the repulsive wall of the $1(a)^3\Sigma^+$ state to reproduce the experimental spectra using LeRoy's BCONT program. A slightly modified version of BCONT is also used to fit the relative transition dipole moments, $\mu_e(R)$, as a function of internuclear separation R, for the various bound-free electronic transitions. We also present bound-free spectra and BCONT simulations for the nearby $4^3\Pi_0$ electronic state of NaCs. [Preview Abstract] |
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E1.00057: Every Atom, Molecule, Compound and Ion Will Exhibit No Motion, Linear, Vibrational and/or Rotational Motion When Created Which May Later Be Modified By External Forces: A Natural Law Stewart Brekke All masses and mass groups have no motion, linear, vibrational and/or rotational motion therefore, when created due to excess energy of creation, all atoms, molecules, compounds and ions will have those properties which may later be modified by outside forces. The basic energy equation for this law of nature is $E=m_0c^2 + 1/2mv^2 + 1/2I\omega^2 + 1/2kx_0^2$. [Preview Abstract] |
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E1.00058: Correlation Study of Endohedrally Confined Atoms (A@C$_{60}$): Alkaline Earth Metal Elements Muhammet F. Hasoglu, Hsiao-Ling Zhou, Steven T. Manson Effects of endohedral confinement on the correlation energy of Be, Mg, and Ca have been investigated using a modified Hartree- Fock (HF) and Multi-Configuration Hartree-Fock (MCHF) method. In this method, an atomic endohedral system (A@C$_{60}$) is approximated as an atom enclosed in an attractive spherical potential well of inner radius $r\sim5.8$ and thickness of $\Delta \sim 1.89$ a.u., and correlation energies are studied as a function of the depth of the confining potential ($0\leq U_0<2$ a.u.). In order to calculate single- and multi- configuration wave functions, we have modified the MCHF codes~ [1] by adding a well potential in addition to the internal atomic potential. Single- and multi-configuration wave functions are obtained from the solution of HF and MCHF equations with the extra potential self-consistently. In general, we have found that valance electrons diffuse outward in the presence of extra potential, which causes the electrons to be further apart. As a consequence, the electron correlations get smaller. In conclusion, our studies has showed that the correlation effects in endohedrally confined atoms gets less important than the free atoms.\\[0pt] [1] C. Froese Fischer et al., Comput. Phys. Commun. \textbf{176}, 559 (2007). [Preview Abstract] |
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E1.00059: Long-Range Three-Body Dispersion Interactions Li-Yan Tang, Zong-Chao Yan, Ting-Yun Shi, James F. Babb There is an increasing interest in producing alkali-metal homonuclear or heteronuclear trimers using the photo- association or magnetic-association techniques. Such trimers are formed near the zero-energy threshold and the constituent atoms typically have large internuclear separations where the dominant interactions are the long-range dispersion interactions. A general theoretical and computational framework is developed for the evaluation of long-range non-additive three-body dispersion interactions. The formalism allows for the possibility of one of the atoms to exist in an excited state. In the case of a homonuclear system such as Li($2s$)Li($2s$)Li($2p$), the long-range interaction will have a lower order $R$-dependence due to the possibility of particle interchange. The lowest order three-body dispersion coefficients are presented for systems involving the H, He, Li atoms and the Li$^+$, Be$^+$ and H$_2^+$ ions. The results of our calculations can be used as reference data for the long-range part of three-body potential energy curves for these systems. [Preview Abstract] |
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E1.00060: Resolving all-order method convergence problems for atomic physics applications Heman Gharibnejad, Ephraim Eliav, Marianna Safronova, Andrei Derevianko The development of the relativistic all-order method, where all single, double, and partial triple excitations of the Dirac-Hartree-Fock wave function are included to all orders of perturbation theory, led to many important results for study of fundamental symmetries, development of atomic clocks, ultracold atom physics, and others, as well as provided recommended values of many atomic properties critically evaluated for their accuracy for large number of monovalent systems. This approach requires iterative solutions of the linearized coupled-cluster equations leading to convergence issues in some cases where correlation corrections are particularly large or lead to an oscillating pattern. Moreover, these issues also lead to similar problems in the CI+all-order method for many-particle systems. In this work, we have resolved most of the known convergence problems by applying two different convergence stabilizer methods, reduced linear equation (RLE) and direct inversion of iterative subspace (DIIS). Examples are presented for B, Al, Zn$^+$, and Yb$^+$. Solving these convergence problems will facilitate many interesting future applications. [Preview Abstract] |
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E1.00061: Polarizability of the $6d_{3/2}$ state of cesium: experiment and theory A. Kortyna, C. Tinsman, J. Grab, M.S. Safronova, U.I. Safronova We report the first polarizability measurements of atomic cesium's $6d_{3/2}$ state. The scalar and tensor polarizabilites are determined from hyperfine-resolved Stark-shift measurements using two-photon laser-induced-fluorescence spectroscopy of an effusive beam. The resulting values are $\alpha_0 = -5270(180){a}^3_0$ and $\alpha_2 = 8650(260){a}^3_0$. We also present relativistic all-order calculation of both the scalar and tensor polarizabilitites. The resulting theoretical values, $\alpha_0 = -5686(121){a}^3_0$ and $\alpha_2 = 8750(82){a}^3_0$ have greater precision than past calculations and are in agreement with the our experimental results. [Preview Abstract] |
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E1.00062: ABSTRACT WITHDRAWN |
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E1.00063: Integration of a fluorometer and a spectrophotometer to measured luminescence of material doped with rare earth Aldo S. Ramirez-Duverger, Raul Garcia-Llamas, Raul Aceves, T.M. Piters The design and construction of a Luminescence-meter optimized to carry out luminescence measurements from material doped with rare earth is presented. This apparatus can work in two modes: In RT mode, it measures the specular reflection or transmission of thick or thin films. In L mode, it measures the luminescence of samples. In both modes it can vary the angle of incidence of the light. Measurements of spectra of reflection and transmission of the microscope slice to test the RT mode were done. The luminescence of KCl thick films doped with Europium for various thicknesses of the samples (2.4 mm to 0.7 mm) are obtained. To prove the sensitivity of the equipment thin film of KCl of about 1 micrometer were grown; the luminescence signal of the later sample barely exceeded the noise. [Preview Abstract] |
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E1.00064: Molecular ion spectroscopy of BaCl$^+$ Steven Schowalter, Kuang Chen, Svetlana Kotochigova, Alexander Petrov, Wade Rellergert, Scott Sullivan, Eric Hudson We demonstrate a simple technique for molecular ion spectroscopy. BaCl$^+$ molecular ions are trapped in a linear Paul trap in the presence of a room-temperature He buffer gas and photodissociated by driving an electronic transition from the ground X$^1\Sigma^+$ state to the repulsive wall of the A$^1\Pi$ state. The photodissociation spectrum is recorded by monitoring the induced trap loss of BaCl$^+$ ions as a function of excitation wavelength. Accurate molecular potentials and spectroscopic constants are determined. Comparison of the theoretical photodissociation cross-sections with the measurement shows excellent agreement. This study represents the first spectroscopic data for BaCl$^+$ and an important step towards the production of ultracold ground-state molecular ions. Future steps include investigating a strong predissociation channel between the first excited $^1\Sigma$ and A$^1\Pi$ states where it is expected that the rovibrational resolution afforded by predissociation spectroscopy will allow us to efficiently measure molecular ion rovibrational temperatures. [Preview Abstract] |
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E1.00065: Nuclear Dynamics Near Conical Intersections in an Intense Field D. Ursrey, C.B. Madsen, B.D. Esry Over the past few decades, considerable progress has been made in understanding the dynamics of diatomic molecules in intense laser fields. There is currently significant interest in extending this same level of understanding to the dynamics of polyatomic systems. One step toward this goal was made recently with benchmark measurements of the intense field dissociation of $\mathrm{H_{3}^{+}}$ [1], a molecule that is certain to play a key role in fundamental investigations of polyatomics. In theoretical studies of polyatomics, one of the primary difficulties is conical intersections between adiabatic potential energy surfaces. At these intersections, the Born-Oppenheimer approximation breaks down. We seek to avoid the technical problems posed by conical intersections by finding a more appropriate representation in which the potential energy surfaces generated are better suited for the study of nuclear dynamics. We will explore methods for generating such potential energy surfaces for $\mathrm{H_{3}^{2+}}$.\\[4pt] [1] J. McKenna {\it et~al.}, Phys. Rev. Lett. {\bf 103}, 103004 (2009). \newline [2] D.~R. Yarkony, Rev. Mod. Phys. {\bf 68}, 985 (1996). [Preview Abstract] |
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E1.00066: Exploration of laser-excitation of Kr Priyanka Rupasinghe, Tao Yang, Neil Shafer-Ray Isotopic detection of the isotopes of Krypton has many important applications in atmospheric science [Zheng-Tian Lu and Peter Mueller, Chapter 4~-~\textit{Atom Trap Trace Analysis of Rare Noble Gas Isotopes}, Advances in Atomic, Molecular, and Optical Physics, Volume 58, 2010, Pages 173-205]. It has been shown that laser cooling and trapping of metastable Kr ($5s\,{\kern 1pt}[3/2]_2 )$ is an effective means to achieve detection efficiencies of 1 part in$10^{12}$. A limiting factor in these studies is the production of metastable Kr, which is currently implemented using an RF discharge [C. Y. Chen et al., \textit{Beam of metastable krypton atoms extracted from a rf-driven discharge}, Review of scientific instruments, Volume 72, No.1, 2001]. Here we report on the success of several experimental attempts at laser-based excitation. [Preview Abstract] |
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E1.00067: Bound energies, oscillator strengths, and multipole polarizabilities for the hydrogen atom with exponential-cosine screened Coulomb potentials Yew Kam Ho, H.F. Lai, Y.C. Lin There have been continued interests for investigations on atomic properties such as the energy eigenvalues, oscillator strengths, and polarizabilities for atoms with exponential-cosine screened Coulomb potentials (ECSCP) [1] in the form of -$e^{-\mu _ r}\cos (\mu _ r)/r$. Here, we study the hydrogen atom affected by ECSCP using B-spline basis for the radial part of the wave functions. We have investigated the bound energies, oscillator strengths, dipole, quadrupole, and octupole polarizabilities for the hydrogen atom interacting with ECSCP. Our results for $E_{1s}$ and$ E_{2p}$ agree with the earlier calculations. For oscillator strengths, we have calculated the 1$s$-2$p$, 1$s$-3$p$, 1$s$-4$p$, 2$p$-3$d$, and 2$p$-4$d $transitions as functions of \textit{$\mu $}. We have also determined the critical values of the screening parameter (\textit{$\mu $}) for ECSCP when the 1$s$ and 2$p$ states become unbound. Comparisons with the earlier results, when available, are made.\\[4pt][1] A. Ghoshal and Y. K. Ho,\textit{ Phys. Rev. A}\textbf{ 79}, 062514 (2009) and references therein. [Preview Abstract] |
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E1.00068: Optical absorption spectrum of Ce@C$_{82 }$ Zhifan Chen, Alfred Z. Msezane Optical absorption spectrum for the Ce@C$_{82}$ endohedral fullerene has been studied using the density-functional theory and the many-body Green's-function approaches. Geometry optimization was performed using the DMol$_{3 }$software. A plane wave approach as implemented in the ABINIT$_{ }$Package has been used to solve the Kohn-Sham equation. Self-energy was evaluated by the GW approximation, which is the product of one-electron Green's function G$_{0 }$ and screened Coulomb interaction W$_{0.}$ Finally the optical absorption spectra have been calculated using the random phase approximation (RPA), RPA plus self-energy correction (RPA-GW) and the Bethe-Salpeter equation (BSE-GW). [Preview Abstract] |
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E1.00069: Relativistic configuration interaction calculations of $n=3-3$ transition energies in highly-charged tungsten ions M.H. Chen, K.T. Cheng Tungsten is a focus of recent fusion research as it is a promising material for plasma-facing components in future magnetic confinement fusion reactors such as the ITER. To understand its influence as a plasma impurity, reliable energy calculations are needed for many ionic stages of tungsten as they show up in relevent emission spectra. In this work, relativistic configuration interaction calculations are carried out for a few $n=3-3$ transitions in Ne-like to Ar-like tungsten. These calculations are based on the no-pair Hamiltonian and use B-spline orbitals as basis functions. QED corrections as calculated from first principle are also included. Results of this work are compared with other theories and with recent EBIT measurements of the $n=3-3$ spectral lines of Ne-like to K-like tungsten [J. Clementson and P. Beiersdorfer, Phys. Rev. A {\bf 81}, 052509 (2010)]. [Preview Abstract] |
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E1.00070: Mapping Jet-cooled Molecular Beam Pulses Using (2+1) REMPI Technique Watheq Al-Basheer, Anis Drira In molecular spectroscopy, understanding the spatial and temporal characteristics of supersonically expanded and jet-cooled molecular beam pulses in vacuum chambers is pivotal in obtaining higher resolution, well-resolved, and enhanced signal to noise ratio. Measurements of (2+1) Resonantly Enhanced Multi-photon Ionization (REMPI) were manipulated to study the shape and structure of a few polar molecules beam pulses (C$_{6}$H$_{10}$O, CH$_{3}$CN, CH$_{3}$I) dissolved in commonly used carrier gases (He, N$_{2}$, Ar) with concentration range (0.1-5{\%}). Non-resonant multi-photon ionization signal of the molecular samples will also be presented in comparison to the REMPI technique. Monitoring produced mass selected cations in a standard time-of-flight and MCP detection system, while varying time delay between sprayed pulses and laser shots interaction, shows a lorentzian like structure of molecular pulses with FWHM comparable to the pulses time duration. Injected molecular beam velocity can be deduced by observing the lorentzian peak center which is sensitive to sample backing pressure and the solvent gas used. Experimental results of the aforementioned samples will be presented and compared against theoretical simulations [Preview Abstract] |
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E1.00071: RF spectroscopy for a ground-state hyperfine transition of $^7$Li using magic polarization Huidong Kim, D. Cho We report the way to eliminate the inhomogeneous broadening for a ground-state hyperfine transition of an alkali metal atom in an optical trap by using a properly polarized trapping field. The ac Stark shift contribution from the vector polarizability has opposite sign for a pair of ground hyperfine levels. It can be used to eliminate the inhomogeneous broadening from the difference in the scalar polarizabilities due to the hyperfine splitting. The size of the vector term is determined by the polarization state of the trapping field, and by controlling the polarization tightly we can achieve a very narrow linewidth. Conceptually, this way is suitable for all alkali metals. However, for the realization tolerance of polarization control is important issue. As a result, we can know that lithium gives the largest tolerance to achieve 1 Hz linewidth as our goal because of its small fine structure. This way, so called magic polarization, is not applicable to 0-0 transition. Therefore that is not solution for atomic clock, however magic polarization has significant implications for an electric dipole moment measurement and quantum information processing using an optical lattice. We are constructing a lithium apparatus for the magic polarization experiment and we will report the progress. [Preview Abstract] |
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E1.00072: Measurement of the 10$p$ fine structure interval of lithium Paul Oxley, Patrick Collins The fine structure interval of the 10$p$ atomic state of 7Li has been measured by laser spectroscopy. Our result of 74.97 (74) MHz for the 10$p$ interval has a precision five times higher than previous measurements of fine structure intervals of Rydberg lithium $p $states. It also provides an experimental value for the only $n $= 10 fine structure interval which is yet to be calculated theoretically and therefore provides a benchmark for such a calculation. In our experiment a beam of lithium atoms is excited by a total of four grating-stabilized diode lasers. The excitation to the 10$p$ state proceeds via the 2$p$ and 3$s$ intermediate states. Three of the lasers are frequency locked to their respective optical transitions and the fourth is scanned across the 10$p$ fine structure components. Optical sidebands imprinted on this fourth laser provide a calibration for the scan and allow a determination of the fine structure interval. [Preview Abstract] |
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E1.00073: Properties of Th$^{3+}$ from Optical Spectroscopy of High-L Rydberg states of Th$^{2+}$ Julie Keele, Shannon Woods, Stephen Lundeen, Charles Fehrenbach The Fr-like Thorium ion, Th$^{3+}$, has one valence electron outside a Rn-like closed shell, but its ground electronic state is $^{2}$F$_{5/2}$ instead of $^{2}$S$_{1/2}$ due to the high nuclear charge [1]. The positions of the lowest seven levels of this ion have been established by optical spectroscopy [2], but no other properties have been measured previously. We measure the properties of the Th$^{3+}$ ground state that control its long-range interactions, such as polarizabilities and permanent moments, by attaching a single electron in a non-penetrating Rydberg state and measuring the details of its binding energy using the Resonant Excitation Stark Ionization Spectroscopy (RESIS) technique [3]. A typical transition is n=29 to n'=72. The laser excitation partially resolves the complex fine structure pattern in the lower state caused by the long-range interactions, and this leads to measurements of the core ion properties controlling those interactions.\\[4pt] [1] U.I. Safronova, et. al., Phys. Rev. A 76, 042504 (2007)\\[0pt] [2] URL = http://www.lac.u-psud.fr/Database/Contents.html\\[0pt] [3] M.E. Hanni, et. al. Phys. Rev. A 82, 022512 (2010) [Preview Abstract] |
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E1.00074: Experimental Investigation of Two-color Polarization Spectroscopy in Rubidium P. Kulatunga, L.R. Andrews, C.I. Sukenik, H.C. Busch We will report on our investigation of two-color polarization spectroscopy of room temperature rubidium atoms in a glass cell when one laser is tuned from the 5S to 5P transition at 780nm and a second laser is tuned from the 5P to 5D transition at 776nm. Both colors are derived from external cavity diode lasers and both common isotopes of rubidium have been studied. We will discuss the laser intensity dependence and the effect of applied magnetic fields on the observed line shapes. Finally, we will demonstrate how the spectra can be applied to frequency stabilization of the diode lasers. [Preview Abstract] |
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E1.00075: Spectroscopy with an unlocked frequency comb Bachana Lomsadze, H.U. Jang, C.W. Fehrenbach, B.D. DePaola We have been developing a novel approach to frequency comb spectroscopy in which the femtosecond oscillator is allowed to free run, without active stabilization of either its repetition frequency (f$_{rep}$) or its offset frequency (f$_0$). The laser light is passed through an atomic vapor target in a MOT. Excitations in the vapor are detected through the collection of ions formed synchronously with the laser pulses. The parameters of the frequency comb that produced the excitation are measured simultaneously using precision counters with GPS disciplined references. As f$_{rep}$ and f$_0$ drift with time, the ion signal will also change as comb teeth match atomic resonances. If the ion signal is plotted as a landscape versus f$_{rep}$ and f$_0$, regular structures appear that identify the comb frequencies producing the excitation. We show data for atomic transitions in Rb. [Preview Abstract] |
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E1.00076: Spectroscopy of lithium atoms using an optical frequency comb Jason Stalnaker, Jose Almaguer, Leanne Sherry The atomic structure of lithium (Li) has aroused a significant amount theoretical and experimental interest as a system in which precision atomic calculations and spectroscopic measurements can be united to yield scientifically significant results. While there have been many experimental investigations of Li spectroscopy, particularly of the isotope shifts and hyperfine structure on the $2\: ^2S_{1/2} \rightarrow 2\: ^2P_{1/2,3/2}$ ($D1$, $D2$) transitions, they suffer from significant disagreements and systematic effects. By utilizing the optical-to-microwave frequency conversion made possible by a stabilized optical frequency comb, we will be able to resolve the discrepancies and measure the optical frequencies of the $D1$ and $D2$ transitions to an accuracy of 5 kHz. We present preliminary data from an atomic beam source and discuss future plans to develop a laser-cooled and trapped source. [Preview Abstract] |
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E1.00077: EIT intensity noise spectroscopy power-broadening and level structure Charles Snider, Michael Crescimanno, Shannon OLeary One particularly interesting (and potentially technologically useful) characteristic of EIT coherence as viewed through intensity noise spectroscopy is its power-broadening resistant features. We detail a connection between the power broadening behavior and the underlying level structure by solving a more realistic quantum optics scenario modeled on recent experiments. [Preview Abstract] |
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E1.00078: Configuration interaction calculation of allowed and forbidden transitions in Fe II Alan Hibbert, Narayan Deb Earlier configuration interaction calculations of Fe II E1 transitions by our group (eg, [1]) have been extended in the number of symmetries incorporated as well as the number of configurations used, and also to forbidden (E2 and M1) lines. We have investigated how the results depend on the choice of the radial functions, particularly of the d-functions. In the poster we will present a small selection of our results, focusing on transitions which relate to astrophysical observations and laboratory measurements. The work has been completed using the general atomic structure package CIV3 [2]. The A-values of many of the transitions are substantially influenced by CI mixing in the wave functions of one or both of the states of the transition. We will discuss how this mixing can be determined as accurately as possible. \\[4pt] [1] G.\ Corr\'{e}g\'{e} and A.\ Hibbert, ApJ, {\bf 627}, L157 (2005); ApJ, {\bf 636}, 1166 (2006). \\[0pt] [2] A.\ Hibbert, Comp.\ Phys.\ Comm., {\bf 9} 141 (1975); R.Glass and A.\ Hibbert, Comp.\ Phys.\ Comm., {\bf 16} 19 (1978). [Preview Abstract] |
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E1.00079: Dielectronic recombination of Ar-like Ni ion and satellite lines of K-like Ni ion Penka Wilcox, Ulyana Safronova, Alla Safronova Dielectronic recombination (DR) is often the dominant recombination process in both astrophysical and laboratory plasmas. The accuracy of DR data and calculations is essential for our understanding of atomic structure and processes in hot matter. In this work the energy levels, radiative transition probabilities, and autoionization rates for [Ne]3s$^{2}$3p$^{5}$3dnl, (n=4-7), [Ne]3s$^{2}$3p$^{5}$4l'nl, (n=4-7), [Ne]3s3p$^{6}$3dnl, (n=4-7), [Ne]3s3p$^{6}$4l'nl, (n=4-7), [Ne]3s$^{2}$3p$^{5}$5l'5l, and [Ne]3s3p$^{6}$5l'5l states in K-like nickel (Ni$^{9+})$ are calculated by the relativistic many-body perturbation theory method (RMBPT code) and the Cowan code. Autoionizing levels above the threshold [Ne]3s$^{2}$3p$^{6}$ are considered. Branching ratios and intensity factors are calculated for the satellite lines and DR rate coefficients are determined for the singly-excited [Ne]3s$^{2}$3p$^{6}$nl, (n=4-7), as well as several doubly-excited states. The important contributions from the doubly-excited states [Ne]3s$^{2}$3p$^{5}$3dnl and [Ne]3s3p$^{6}$3dnl ( n $>$ 7) to DR rate coefficients are estimated by extrapolation of all atomic parameters. Total DR rate coefficient is derived as a function of electron temperature. [Preview Abstract] |
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E1.00080: Atomic processes under varying plasma environments Tu-nan Chang, T.K. Fang We present a quantitative estimate for a number of atomic properties based of the use of Debye-Huckel (DH) screening Coulomb and modified DH screening potential for a charged particle in a plasma [1]. We will examine the variation of the ionization thresholds and the resulting reduction in the number of bound excited states of atoms. The effect on the atomic transitions and doubly excited resonance widths will also be studied in detail. \\[4pt] [1] P. K. Shukla and B. Eliasson, Phys. Lett. A 372, 2897 (2008). [Preview Abstract] |
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E1.00081: Precision Lifetime Measurement of the Rubidium $5P_{3/2}$ State Brian Patterson, Jerry Sell, Randy Knize We will report measurement results of the rubidium $5P_{3/2}$ atomic state lifetime. The measurement technique uses a single pulse from a mode-locked Ti:Sapphire laser to excite rubidium atoms in counter-propagating thermal beams to the $5P_{3/2}$ state. A subsequent laser pulse is amplified in a regenerative amplifier and frequency-doubled, which ionizes atoms in the excited state (but not from the ground state). The photoions are collected and counted as the time delay between the excitation and ionization pulses is varied. The dominant systematic effects using this technique include radiation trapping, hyperfine quantum beats, and effects from the misalignment of the excitation and ionization laser beams. We recently used this technique to achieve a total measurement uncertainty of 0.12$\%$ for the $6P_{3/2}$ state lifetime of cesium, and anticipate a comparable precision may be achieved for the rubidium $5P_{3/2}$ state. [Preview Abstract] |
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E1.00082: ABSTRACT WITHDRAWN |
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E1.00083: Borromean bindings in H$_{2}^{+ }$ with screened Coulomb potentials Sabyasachi Kar, Y.K. Ho The stability of the bound $P$ and $D$ states of the H$_{2}^{+}$ molecular ion, where the nuclei and the electrons interacts with a screened Coulomb (Yukawa-type) potential exp(-\textit{$\mu $}r)/r, has been studied for different values of the screening parameters \textit{$\mu $}. We have determined the values of the bound $^{3}P^{o }$(\textit{$\nu $}=0, $J$=1), $^{3}P^{o }$(\textit{$\nu $}=1, $J$=1), $^{1}D^{e }$(\textit{$\nu $}=0,$ J$=2), and $^{1}D^{e }$(\textit{$\nu $}=1,$ J$=2) states energies for different values of the screening parameters using highly correlated exponential wave-functions in the framework of Ritz variational principle. The critical values of the screening parameters for the bound states are reported for which the H$_{2}^{+}$ system is stable, while all the possible fragments are unbound, that is, it shows Borromean binding for the three-body systems [1]. We have determined the range of the Borromean windows for the lower-lying $S$, $P$ and D states.\\[4pt] [1] A. Ghoshal and Y. K. Ho, \textit{Int. J. Quan. Chem.} (2011), published online; and references therein. [Preview Abstract] |
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E1.00084: Global Analysis of Data on the Spin-Orbit Coupled $A^{1}\Sigma_{u}^{+}$ and $b^{3}\Pi_{u}$ States of Cs$_{2}$ T. Bergeman, H. Salami, Jianmei Bai, E.H. Ahmed, B. Beser, Y. Guan, S. Kotochigova, A.M. Lyyra, S. Ashman, C.M. Wolfe, J. Huennekens, F. Xie, D. Li, Li Li, M. Tamanis, R. Ferber, A. Drozdova, E. Pazyuk, A.V. Stolyarov, J.G. Danzl, H.-C. N\"{a}gerl, N. Bouloufa, O. Dulieu, C. Amiot Experimental data from Orsay, Tsinghua, Temple, Innsbruck and Riga on the A and b states of Cs$_{2}$ have been modeled so as to extract potential curves and spin-orbit coupling functions.\footnote{J. Bai et al., accepted for publication in PRA.} The fitted term values are relevant for the production of cold Cs$_{2}$ ground state molecules from cold Cs atoms or from Feshbach resonance states. [Preview Abstract] |
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E1.00085: Interactions of polar alkali dimers Jason Byrd, John Montgomery, Jr., Robin C\^{o}t\'{e} The effects of external electric static fields on the interactions of polar alkali diatoms for the purposes of alignment is investigated for a variety of trapping geometries and external field strengths. We also present new results for the dispersion and induction van der Waals coefficients calculated using the sum over states method of time dependent density functional transition moments. Additionally the static electric moments and polarizabilities for each heteronuclear alkali diatom have been calculated. These new results are used to accurately model the interactions between polar alkali molecules in the long range by a van der Waals expansion up to $R^{-8}$. We find that strong alignment of specific heteronuclear diatoms is possible with strong but physically realizable external electric fields. [Preview Abstract] |
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E1.00086: Spin-orbit coupling effect in the low-lying states of Rb$_{2}$, Cs$_{2}$ and RbCs molecules Andrey Stolyarov, Thomas Bergeman We present the results of \emph{ab initio} calculations on the potential energy curves, transition dipole moments, spin-orbit and angular coupling matrix elements between the electronic states of Rb$_{2}$, Cs$_{2}$ and RbCs molecules converging to the lowest three dissociation limits. The quasi-relativistic matrix elements have been evaluated for a wide range of internuclear distance in the basis of the spin-averaged wavefunctions corresponding to pure Hund's coupling case (\textbf{a}) by using of small (9-electrons) effective core pseudopotentials of both atoms. The core-valence correlation has been accounted for a large scale multi-reference configuration interaction method combined with semi-empirical core polarization potentials. The calculated spin-orbit (SO) coupling matrix elements were involved in the deperturbation treatment of the of the fully mixed $A^{1}\Sigma^{+}$ and $b^{3}\Pi$ states as well as to estimate a second order SO effect in the ground singlet $X^{1}\Sigma^{+}$ and triplet $a^{3}\Sigma^{+}$ states. The resulting transition dipole moments and potentials were used to predict radiative lifetimes and emission branching ratios of excited vibronic states while the calculated angular coupling matrix elements were transformed to $\Lambda$-doubling constants of the $^1\Pi$ states. The accuracies of the present results are discussed by comparing with experimental data and preceding calculations. [Preview Abstract] |
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E1.00087: Towards trapping cold molecular nitric oxide Parshuram Dahal, Eric Abraham, James Coker, Neil Shafer-Ray, John Furneaux We present a method for filtering, guiding and magnetic trapping of cold molecular nitric oxide (NO). In the filtering process, the low field electric seeking molecules interact with an inhomogeneous electrostatic field of a hexapole guide which is exploited to select the slow molecules from a cold molecular source. The resulting cold fraction in the non-magnetic $^{2}\Pi _{1/2}$ ground state is directed into a magnetic trap where it is optically pumped into the $^{2}\Pi _{3/2 }$fine structure state which is magnetically trapped. Full simulation of the procedure will be presented and progress toward experimental results will be discussed. [Preview Abstract] |
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E1.00088: Spectroscopy of Rydberg atoms in a high-magnetic-field atom trap Eric Paradis, Stefan Zigo, Georg Raithel We study cold Rydberg atoms and their interactions in a high-magnetic-field atom trap with a central magnetic field of 2.6 Tesla. The presence of the large magnetic field creates a wide spectrum of non-degenerate Rydberg states that can be tailored towards Rydberg-atom interaction experiments by fine-tuning the magnetic field and adding a longitudinal electric field. To enable these experiments, we have calculated the spectra of high-lying Rydberg states of Rubidium 85 in parallel magnetic and electric fields, taking all known quantum defects and fine-structure effects into account. We identify near-degenerate pairs of states with equal magnetic quantum number and opposite $z$-parity (for electric field zero). These states couple strongly when a parallel electric field is applied, resulting in large, tunable permanent electric dipole moments that should enhance Rydberg-Rydberg interactions. Field tuning can also be used to induce energy exchange resonances (F\"{o}rster resonances). In this presentation, we will discuss the calculated spectra and spectroscopic measurements on Rydberg atoms in the magnetic atom trap. Progress towards superimposing a far-off-resonant optical trap onto the high-magnetic-field trap is also reported. [Preview Abstract] |
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E1.00089: ABSTRACT WITHDRAWN |
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E1.00090: ADVANCES IN NV CENTERS |
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E1.00091: Characterization of NV diamond samples Linh Pham, David Le Sage, Nir Bar-Gill, Chinmay Belthangady, Keigo Arai, Daniel Twitchen, Matthew Markham, Ronald Walsworth We report recent progress in studying the effects of various diamond synthesis and processing techniques on the spin coherence behavior of the nitrogen-vacancy (NV) defect center. Measurements were made on single NV centers as well as on small ensembles in diamond samples containing varying concentrations of Nitrogen and 13Carbon spin impurities and which have been subjected to a range of post-growth irradiation and annealing recipes. [Preview Abstract] |
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E1.00092: New techniques for NV-diamond ensemble magnetometry Keigo Arai, David Le Sage, Nir Bar-Gill, Chinmay Belthangady, David Glenn, Alexei Trifonov, Ronald Walsworth We describe new techniques for precision magnetometry using ensembles of NV centers in diamond. One technique uses the large refractive index of diamond as a light guide to achieve much higher fluorescence detection efficiency than provided by high NA microscope objectives. Another technique employs the m = +/-1 basis states of the NV triplet ground state, which may give improved magnetometry for small static magnetic fields. Dynamic decoupling pulse sequences can also improve the effective spin coherence time for NV ensembles. An alternate approach measures the absorption of the NV excitation light by an optically thick diamond sample. [Preview Abstract] |
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E1.00093: NV dark state dynamics David Le Sage, Nir Bar-Gill, Chinmay Belthangady, David Glenn, Alexei Trifonov, Ronald Walsworth We present a study of the dynamics of light-induced transitions between the bright and the dark states of the negatively charged NV center in diamond. We investigate two proposed physical mechanisms for the origin of the long-lived dark state, namely charge conversion and an unidentified singlet state. Finally we investigate the dependence of these dynamics on the NV spin state for possible application in super-resolution microscopy and enhanced-contrast magnetometery. [Preview Abstract] |
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E1.00094: Non-classical states of NV and N impurities in diamond Chinmay Belthangady, Nir Bar-Gill, David Le Sage, My Linh Pham, Paola Cappellaro, Ronald Walsworth We present schemes that take advantage of the interactions of NV centers in diamonds with neighboring N impurities, which may allow improved NV performance as qubits and quantum sensors. For example, we describe pulse sequences that may allow polarization of the N spins and entanglement of N spins with the NV spin. Applying such schemes to NV ensembles may allow creation of a large number of entangled NV-N pairs. In addition, a similar approach may allow creation of a Schrodinger cat state of several N spins interacting with one NV. Finally, we find that under certain conditions, N- mediated NV-NV interactions become important, which may allow creation of squeezed states in the NV ensemble. [Preview Abstract] |
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E1.00095: Color centers in diamond: versatile and powerful tools for bioimaging Huiliang Zhang, David Glenn, Alexei Trifonov, My Linh Pham, David Le Sage, Narayanan Kasthuri, Richard Schalek, Jeff Lichtman, Ronald L. Walsworth We present recent progress in the application of nitrogen vacancy (NV) and other color centers in diamond to demanding bioimaging applications, including: (i) nanodiamond cathodoluminescence (CL) to provide molecular-function correlated color to electron microscopy of the connections between neurons (``Connectomics''); (ii) super-resolution optical imaging of functionalized nanodiamonds in brain tissue using variants of STED, GSD or STORM techniques; and (iii) magnetic field sensing and imaging of neural activities using an NV- diamond magnetometer. [Preview Abstract] |
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E1.00096: Towards room temperature magnetic sensing of a single electron spin in biological systems Nicholas Chisholm, Peter Maurer, Georg Kucsko, Peggy Lo, Norman Yao, Brendan Shields, Hongkun Park, Mikhail Lukin We report on recent progress of room temperature sensing for biological applications using nitrogen-vacancy (NV) centers in diamond. First, we discuss progress made toward measuring the magnetic field of a single electron spin using as a sensor the electron spin of an NV in bulk diamond. This is approached by attaching commercially available nitroxide spin labels to the functionalized surface of the bulk diamond, and using a nearby NV center as a sensor. In addition, we present progress toward the study of functionalized nanodiamonds in living cells used as single spin label probes of local magnetic field environments. The ability to sense magnetic fields with sub-micrometer resolution with sensitivity capable of detecting a single electron spin is of major importance to the biological sciences. [Preview Abstract] |
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E1.00097: All optical real-time measurement and preparation of nuclear spin states around an individual NV center in diamond Emre Togan, Yiwen Chu, Vincent Jacques, Alp Sipahigil, Alexander Kubanek, Adi Pick, Michael Gullans, Eric Kessler, Geza Giedke, Susanne Yelin, Ignacio Cirac, Atac Imamoglu, Mikhail Lukin Atomic coherence effects such as Coherent Population Trapping (CPT) have many important applications in AMO physics ranging from optical manipulation of atomic spin states, to slow and stopped light as well as sub-recoil laser cooling via Velocity Selective Coherent Population Trapping (VSCPT). In this work we demonstrate measurement and manipulation of electronic and nuclear spin states associated with an NV center in diamond using CPT. To this end we use the recently identified lambda-type two photon transitions in NV centers. The intrinsic magnetic field sensitivity of the CPT allows us to measure the instantaneous Overhauser field associated with the $^{13}$C bath. We show that this quantum measurement technique can be used to prepare a state of the $^{13}$C bath, which has much smaller uncertainty in the Overhauser field associated with it. Such preparation is verified by observing modification / narrowing of the transmission window. Potential applications include improved coherence properties of the electron spin qubits and all optical magnetic sensing with improved sensitivities. [Preview Abstract] |
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E1.00098: Measurement-Based Nuclear Spin Cooling in NV Centers Adi Pick, Michael Gullans, Emre Togan, Yiwen Chu, Alp Sipahigil, Geza Giedke, Susanne Yelin, Mikhail Lukin Interactions between the electronic spin of the NV center and nuclear spins in its environment are a main source for decoherence in this system. Cooling down the surrounding nuclei will improve the coherence properties of the center, and therefore is desirable for potential applications. We propose utilizing dark resonance spectroscopy to narrow down the nuclear spin state distribution. In this scheme, the nuclei undergo anomalous spin diffusion at a rate which is proportional to the amount of electronic excitation in the system. The detunings of the lasers which illuminate the center distinguish a nuclear dark state which becomes a trapping state in the diffusion process. We analyze the mechanisms which limit this cooling procedure and explore the resulting minimal resolvable linewidth. We hypothesize that NV centers, which interact strongly with just a few nuclear spins, are promising candidates for achieving optimal line narrowing. [Preview Abstract] |
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E1.00099: Sensing thermal motion of a mechanical resonator using a single spin qubit in diamond Shimon Kolkowitz, Ania Bleszynski Jayich, Peter Rabl, Steven Bennet, Quirin Unterreithmeier, Jack Harris, Mikhail Lukin We present experimental results demonstrating the detection of the motion of a magnetized mechanical cantilever using a single spin qubit associated with a nitrogen-vacancy (NV) defect center in diamond. This setup is predicted to enable strong, coherent coupling between the NV electronic spin and the motion of the cantilever, allowing for the mechanical analog of cavity quantum electrodynamics [1]. To this end, we use the NV spin to detect both driven and thermal motion of a magnetic force microscope cantilever at room temperature, reading out the spin state optically using the spin-selective fluorescence of the NV. This method utilizes the high sensitivity of the NV spin precession to Zeeman shifts caused by the a.c. magnetic field induced by the motion of the cantilever. Finally, we discuss potential applications of our approach to the realization of quantum spin transducers using arrays of coupled spin-cantilever pairs [2]. 1. Rabl, P. \textit{et al.} Strong magnetic coupling between an electronic spin qubit and a mechanical resonator. \textit{Physical Review B}\textbf{ 79}, 41302 (2009). 2. Rabl, P\textit{. et al.} A quantum spin transducer based on nanoelectromechanical resonator arrays\textit{. Nature Physics} \textbf{6}, 602--608 (2010). [Preview Abstract] |
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E1.00100: Long-lived solid-state room-temperature quantum memory Peter Maurer, Georg Kucsko, Nick Chisholm, Norman Yao, Liang Jiang, Alexey Gorshkov, Alexander Zibrov, Alexander A Zibrov, Philip Hemmer, Ignacio Cirac, Mikhail Lukin One of the major obstacles in quantum information technology is to prevent a quantum bit (qubit) from dephasing, while still being able to manipulate and readout the qubit state on a fast time scale. We report recent progress towards the realization of a room temperature quantum register that maintains it's quantum mechanical nature for seconds while still allowing for qubit manipulation in the MHz regime. To achieve this, we utilize a quantum register consisting of an electronic ancilla spin and a proximal nuclear memory spin; the register is associated with single nitrogen-vacancy (NV) defect centers in diamond. In order to maximize the coherence time of the nuclear spin, we employ dynamical decoupling using microwave and optical pulses. The realization of a solid state quantum memory with long coherence times at room temperature opens up new possibilities for applications of quantum information systems. [Preview Abstract] |
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E1.00101: Spectrally Decomposing the spin-bath environment of an NV-center in Diamond Nir Bar-Gill, Chinmay Belthangady, David Le Sage, My Linh Pham, Jeronimo Maze, Paola Cappellaro, Ronald Walsworth NV centers in diamonds have been proposed as candidates for quantum information processing and as magnetic field sensors. Furthermore, dynamical decoupling techniques have been demonstrated to improve the quantum coherence of these systems. Here we propose using the NVs as precise probes of their magnetic environment's full spectral density. Through a combination of applied pulse sequences and coherence measurements, a Fourier-like decomposition of the environment's temporal correlation function can be deduced. This technique could be useful for characterizing the dependence of the surrounding spin bath on density, external magnetic field, dimensionality and more. Also, this method could be useful in identifying surface magnetic impurities and as a chemical sensor. Finally, this approach could be extended to study the quantum many- body nature of the spin bath. [Preview Abstract] |
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E1.00102: NEW EXPERIMENTAL TECHNIQUES |
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E1.00103: A 408 nm Laser System to Drive Stimulated Raman Transitions James L. Archibald II, Christopher J. Erickson, Dallin S. Durfee We will discuss a diode laser system that produces two laser beams, differing in frequency by 1 GHz, that can be used to drive Raman transitions in $^{87}$Sr$^+$. This system will be used to generate the $\pi$ and $\pi/2$ pulses in an ion interferometer. The laser consists of a grating stabilized master laser. This is then passed through an AOM and retroreflected back through the AOM in order to provide two frequency-shifted beams. These beams are then used to injection lock two slave lasers, in a scheme similar to the one described in [1]. The AOM can be modulated with a stability better than 1 Hz. Thus we guarantee that the light output from the slaves is at a constant detuning, while drift from the master laser corresponds to common mode drift (to which the Raman transition is less sensitive). We will also discuss a technique used to improve laser stability similar to the scheme described in [2] but using the measured impedance of the diode rather than the amplitude noise on the light to generate an error signal. \\[4pt] [1] P. Bouyer, T. L. Gustavson, K. G. Haritos, and M. A. Kasevich, Optics Letters 21, 1502-1504 (1996)\\[0pt] [2] Sheng-wey Chiow, Quan Long, Christoph Vo, Holger M\"uller, and Steven Chu, Applied Optics 46, 7997-8001 (2007) [Preview Abstract] |
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E1.00104: Development of a multipass cell for atomic collision experiments in the presence of a laser field N. St.J. Braithwaite, B.A. deHarak, N.L.S. Martin, A.J. Murray, K.L. Nixon Experiments on electron-impact ionization in the presence of a pulsed laser field are currently being carried out at the Universities of Manchester, UK and Kentucky, USA. The experiments are difficult because, with a typical laser pulse length of a few nanoseconds and a repetition rate of order 10 Hz, the live time is equivalent to a few seconds per year. In order to increase the effective live time, one possible approach is to create a ``multipass cell'' in which a laser pulse is passed several times through the interaction region. A scheme will be presented which uses spherical or parabolic mirrors to create a non-repetitive path which passes through the interaction region many times before being guided out of the cell. The pulse may then either be dumped or passed through a regenerative amplifier (thus allowing for any losses in the cavity), and then re-injected into the original path, so as to increase the interaction time by several orders of magnitude. [Preview Abstract] |
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E1.00105: Atomic clocks based on extened-cavity diode laser in multimode operation Sin Hyuk Yim, D. Cho We demonstrated the possibilities to develope an atomic clock based on coherent population trapping(CPT) without using a local oscillator and a modulator. Instead of using a modulator, we use two modes from a single extended-cavity diode laser in multimode operation. Two different types of feedback system are applied to stabilize a difference frequency between the two modes and eliminate the need for an extra frequency modulation. In the first type, we employ an electronic feedback using dispersion of the CPT resonance as an error signal. The two modes are phase locked with reference to a dispersion signal from a CPT resonance of $^{85}$Rb at 3.036 GHz ground hyperfine splitting. We use D1 transition at 794.8 nm with lin$\perp$lin polarizations to obtain large-contrast CPT signal. Allan deviation of the beat frequency between the two modes is $1 \times 10^{-10}$ at 200-s integration time. In the second type, we employ optoelectronic feedback to construct an opto-electronic oscillator(OEO). In an OEO, the beating signal between two modes is recovered by a fast photodiode, and its output is amplified and fed back to the laser diode by using a direct modulation of an injection current. When the OEO loop is closed, oscillation frequency depends on variations of the loop length. In order to stabilize an OEO loop length and thereby its oscillation frequency, CPT cell is inserted to play a role of microwave band pass filter. Allan deviation of the CPT-stabilized OEO is $2\times 10^{-10}$ at 100-s integration time. [Preview Abstract] |
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E1.00106: Using Laser Induced Breakdown To Probe Pressure Bruno deHarak, Daniel LaRocca, Evan Baker, Nicholas Goble The measurement of non-uniform gas pressure as a function of position within a chamber can be difficult, with the level of difficulty increasing as a function of the desired spatial resolution. Such measurements are important for characterizing parameters affecting experiments; e.g., profiling a gas jet being used as a target. In this work we will discuss the use of laser induced breakdown to measure pressure at well localized ($\sim$1 mm$^3$) positions within a chamber. A detailed description of the apparatus, and preliminary results, will be presented. [Preview Abstract] |
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E1.00107: Development of a stable, low-cost diode laser system for use in atom optics experiments Eryn C. Cook, Paul J. Martin, Daniel A. Steck We present the design and characterization of an external cavity diode laser system optimized for high stability, low cost, and ease of in-house assembly. The Littrow cavity is hermetically sealed, CNC machined from a single aluminum block to reduce sensitivity to temperature changes and mechanical vibrations, and features a stiff and light diffraction grating arm for low-frequency noise suppression. A custom-molded silicon external housing further isolates the system from environmental noise. Beam shaping, optical isolation, and fiber coupling are integrated, and the design is easily adapted to many commonly used wavelengths. We present resonance data and linewidth and stability characterization of the new design. [Preview Abstract] |
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E1.00108: Novel Ultrahigh Vacuum System for Chip-Scale Trapped Ion Quantum Computing Shaw-Pin Chen This presentation reports the experimental results of an ultrahigh vacuum (UHV) system as a scheme to implement scalable trapped-ion quantum computers that use micro-fabricated ion traps as fundamental building blocks. The novelty of this system resides in our design, material selection, mechanical liability, low complexity of assembly, and reduced signal interference between DC and RF electrodes. Our system utilizes RF isolation and onsite-filtering topologies to attenuate AC signals generated from the resonator. We use a UHV compatible printed circuit board (PCB) material to perform DC routing, while the RF high and RF ground received separated routing via wire-wrapping. The standard PCB fabrication process enabled us to implement ceramic-based filter components adjacent to the chip trap. The DC electrodes are connected to air-side electrical feed through using four 25D adaptors made with polyether ether ketone (PEEK). The assembly process of this system is straight forward and in-chamber structure is self-supporting. We report on initial testing of this concept with a linear chip trap fabricated by the Sandia National Labs. [Preview Abstract] |
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E1.00109: Rapid inversion of velocity map images for adaptive femtosecond control C. Rallis, P. Andrews, R. Averin, B. Jochim, N. Gregerson, E. Wells, M. Zohrabi, S. De, B. Gaire, K.D. Carnes, I. Ben-Itzhak, B. Bergues, M.F. Kling We report techniques developed to utilize three dimensional momentum information as feedback in adaptive femtosecond control of molecular systems. Velocity map imaging of the dissociating ions following interaction with an intense ultrafast laser pulse provides raw data. In order to recover momentum information, however, the two-dimensional image must be inverted to reconstruct the three-dimensional photofragment distribution. Using a variation of the onion-peeling technique, we invert 1054 x 1040 pixel images in under 1 second. This rapid inversion allows a slice of the momentum distribution to be used as feedback in a closed-loop adaptive control scheme. [Preview Abstract] |
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E1.00110: Mode-hop-free tuning range over 140 GHz of external cavity diode lasers Sourav Dutta, D.S. Elliott, Yong P. Chen We report a mode-hop-free tuning range of over 140 GHz for a home-built external cavity diode laser, using a diode whose front facet is not anti-reflection coated. We achieved this by using a short external cavity and by simultaneously tuning of the internal and external modes of the laser. The general applicability of the method, combined with the compact portable mechanical and electronic design, makes it well suited for both research and industrial applications. [Preview Abstract] |
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E1.00111: Generation of 480nm cw light for Rydberg excitation of Rb J. Sedlacek, A. Schwettmann, J.P. Shaffer Our setup for generating tunable 480 nm light for Rydberg excitation is detailed. A laser diode is tuned to 960nm in an external cavity. The light from the diode laser is amplified through a tapered amplifier. It is then frequency doubled using a single pass PPLN crystal. We use a programmed FPGA to lock the diode to a Fabry-Perot cavity. The result is narrow linewidth cw light with sufficient intensity for Rb Rydberg atom excitation and Rydberg atom EIT experiments. [Preview Abstract] |
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E1.00112: Injection locking of 767 nm laser diodes with RF modulation Charles Conover We have explored RF modulation of 767 nm injection-locked diode lasers as a way to generate the two colors, separated by approximately 462 MHz, necessary for magneto-optical trapping of K-39. We discuss the differences in behavior between standard Fabry-Perot lasers and antireflection-coated diodes, and the behavior of the lasers with changes in temperature, DC bias current, RF power, injected laser intensity, and modulation frequency. Using modest ($<$10 mW) RF power, we are able to stably generate optical power in the first-order sidebands of greater than 25\% of the carrier power, with significant asymmetry between the upper and lower sidebands affected by appropriate choice of parameters. [Preview Abstract] |
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E1.00113: Noise Characterization of an Injection-locked Ti:Sapphire Laser Daniel Thrasher, Matt Burbidge, Miriam Conde, Scott Bergeson We report amplitude noise and laser linewidth measurements in an injection-locked ti:sapphire laser system. A low power diode laser is amplified to 1.6 W at 846 nm. Amplitude noise is measured using a high-speed photodiode. Frequency noise is measured relative to a low-noise commercial ti:sapphire laser using an offset lock and heterodyne technique. Under optimal conditions the relative rms amplitude noise is 1\%. The linewidth of the injection-locked laser is 360 kHz. [Preview Abstract] |
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E1.00114: A High Power Amplifier for a Single Mode 1064 Laser R.W. Stites, K.M. O'Hara We report on the construction of a high power amplifier system for a single mode 1064 nm laser. At the heart of this device is a 0.27\% neodymium doped yttrium orthovanadate crystal that is double end pumped by two 30 Watt broadband diode arrays at 808 nm. For a 50 Watt TEM$_{00}$ single freqency seed laser, we have observed an amplified power output in excess of 60 Watts for single pass configuration. A further increase in output power can be attained by retroreflecting the beam back through the crystal a second time. Such a device has direct application in the construction of optical lattices where high power single frequency lasers are required. [Preview Abstract] |
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E1.00115: Efficient Generation of Pure High-Order Laguerre-Gaussian Laser Beams Y. Zhang, E.L. Hazlett, R.W. Stites, K.M. O'Hara High-order Laguerre-Gaussian laser beams are useful for trapping atoms, transferring angular momentum to cold gases and microscopic objects, and increasing the sensitivity of gravitational wave detectors. We report the experimental generation of pure high-order Laguerre-Gaussian laser beams ${\mathrm{LG}}^{l=12}_{p=0}$, where $l$ and $p$ are the azimuthal and radial mode indices respectively. We use a spiral phase plate with a $12 \times (2 \pi)$ total phase winding to convert a fundamental Gaussian beam to a superposition of ${\mathrm{LG}}^{l=12}_p$ beams. A plano-concave optical cavity is then used as a spatial filter to remove all radial modes of the beam except the $p=0$ mode. We will report on how we optimize the overall efficiency of this technique to maximize the power in the pure ${\mathrm{LG}}^{l=12}_{p=0}$ mode. [Preview Abstract] |
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E1.00116: MATTER WAVE INTERFEROMETRY |
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E1.00117: Analysis of cold-atom interferometer with optical beam splitting and recombination Ebubechukwu Ilo-Okeke, Alex Zozulya Cold atom interferometers with optical beam splitting and recombination use off-resonant laser pulses to split a cloud of Bose-Einstein condensates (BECs) into two clouds that travel along different paths. During the interferometric cycle, spatial phase distortion and phase diffusion develop across the clouds in addition to the environment-introduced phase of interest accumulated during the interferometric cycle. At the end of the interferometric cycle, the same optical laser pulses used at the splitting of the clouds are used to recombine the clouds. After recombination, the population of atoms found in the cloud at rest and the moving clouds is dependent on the relative phase between the two clouds. We derive an analytical expression for the probability density of counting any number of atoms within each cloud and discuss its features as function of inter-atomic strengths and the spatial phase distortion. [Preview Abstract] |
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E1.00118: A Strontium$^{87}$ Ion Interferometer Christopher J. Erickson, James L. Archibald II, Jarom Jackson, Dean Anderson, Michael Hermansen, Mark Cunningham, Dallin S. Durfee We describe a matter-wave interferometer based on Sr$^{87+}$. The ions are generated from a laser-cooled strontium beam that is photo-ionized using a two-photon transition to an auto- ionizing state in the continuum. The ionization occurs between two electrodes, allowing us to accelerate the ions to any desired energy from a few meV to 20 keV. Each ion's quantum wave is split and recombined using stimulated Raman transitions between the hyperfine ground states of Sr$^{87+}$. The two required optical frequencies for this transition are created by frequency-shifting a master laser in opposite directions by half of the 5 GHz ground-state hyperfine splitting. We can then determine the interferometer phase from the fluorescence of one of the ground states. We will discuss the theory of operation, experimental methods, and potential applications of the device. [Preview Abstract] |
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E1.00119: Two dimensional analysis of an atom Michelson interferometer Rudra Kafle, Alex Zozulya A Bose-Einstein condensate (BEC)- based atom Michelson interferometer is a matter wave interferometer where the splitting of an atomic wave packet from a BEC, and the recombination of the split wave packets take place at the same location. This type of interferometer can be designed with a single reflection pulse, double reflection pulses, or no reflection pulses at all. In an interferometer with no reflection pulses, the atomic wave packets undergo a full cycle oscillation in a weakly confining harmonic magnetic trap before they are finally recombined. If the split condensates have transverse components of initial momenta caused by laser misalignments, etc., the motion of the condensates becomes two dimensional. We study the dynamics of the split condensates in a simple two dimensional model, and analyze the performance of an interferometer in an atom Michelson geometry. [Preview Abstract] |
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E1.00120: Applications of the Stochastic Gross-Pitaevskii equation to Atom Interferometers Donatello Gallucci, Stuart P. Cockburn, Nick P. Proukakis The stochastic Gross-Pitaevskii equation (SGPE) has proven to be a versatile tool for modeling weakly-interacting quasi-one-dimensional bosonic gas experiments at finite temperatures. In this work we examine the validity of its application to the experimentally-relevant case of transversally-split atom interferometers. While the Bose gas samples used in interferometry are typically very elongated, and therefore require a model including phase and density fluctuations, a full description of the dynamical process of splitting and recombining such samples requires a three-dimensional formulation. We therefore consider key issues which arise in solving the SGPE in greater than one-dimension, such as the role of the momentum cut-off, due to the inherently classical field nature of the approximations on which this model is based, and the closely related issue of partial inclusion of important thermal mode dynamics. Maintaining a stochastic element to the quasi-condensate dynamics is shown to result in an axially-varying phase difference across the split interferometer arms, and the emerging patterns upon recomination are analysed. The possibility of modeling existing experiments is also considered. [Preview Abstract] |
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E1.00121: Exact Series Solutions for the Quantum Modes of Atomic Waveguides William Golding Miniature magnetic waveguides for atoms are used in many atom chip designs. For very cold atoms the quantum modes of these guides are important. The simplest field configuration usually assumed for a straight atom chip guide is a transverse magnetic quadrupole combined with a uniform longitudinal bias field often called a Ioffe field. The Ioffe field is used both to prevent the possibility of Majorana transitions and to make an approximate quantum solution of the guide problem easier to obtain. However, the introduction of the Ioffe field has other effects that may reduce the performance of atom guides in practice. Among these effects are reduction of waveguide mode spacing and the introduction of Landau-Zener transitions due to Ioffe field gradients or variations. In addition, uniform Ioffe fields can be difficult to incorporate into general atomic guides that need to follow unconstrained curved paths. A series technique has been developed for exact calculations of both the eigenvalues and the quantum modes of these guides for arbitrary Ioffe fields. [Preview Abstract] |
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E1.00122: Microwave guiding of electrons in a planar quadrupole guide Roman Fr\"ohlich, Johannes Hoffrogge, Mark A. Kasevich, Peter Hommelhoff We present the first experimental realization of electron guiding in a linear Paul trap.\footnote{J. Hoffrogge, R. Fr\"ohlich, M. A. Kasevich and P. Hommelhoff - submitted (2010) arXiv:1012.2376v1} The guiding potential is generated by a microfabricated electrode layout on a planar substrate, similar to surface-electrode ion traps. In comparison to ion traps much higher driving frequencies are necessary. To obtain stable trajectories, we drive the structure at 1\,GHz leading to a guiding potential with transverse frequencies of about 150\,MHz. The feasibility of electron guiding is demonstrated by forcing a low energy electron beam traveling 500\,$\mu$m above the chip's surface on a curved path. For electron energies between 1\,eV and 5\,eV we present the influence of trap stability and depth on the electron signal over a wide range of driving frequencies and voltages. Furthermore we characterize second generation substrates fabricated by thick film lithography that minimize charging effects and discuss realizing more complex guiding potentials like e.g. beam splitters. The future prospects of combining these electron guiding structures with coherent electron emitters like single atom tips will be discussed as well. [Preview Abstract] |
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E1.00123: Generating a double-well on an atom chip Violeta Prieto, Jason Alexander, Christopher Rowlett, William Golding, Patricia Lee We report on recent experimental progress towards developing a compact atom interferometer on an atom chip using a double-well potential. The interferometer uses 87Rb atoms magnetically confined in an atomic waveguide produced by wires on the surface of a lithographically patterned chip. The double-well potential can be created by dynamically changing the current configuration on our atom chip, as well as by combining radio-frequency and static magnetic fields. We model combinations of different current configurations with various external bias fields that could offer the means to coherently split the atomic cloud through dynamically adjusting the currents and bias fields. We also study the splitting created by using a combination of RF applied through the chip wires or external wire loops and a static magnetic field produced by a z-wire and bias coils. Depending on the polarization of the RF field, the orientation and the shape of the induced dressed-state potential can be manipulated, creating double-well configurations with different sensitivities to gravity. We consider real-time transformations between different double-well configurations adiabatically and non-adiabatically, and study their effects on the initially trapped atoms. [Preview Abstract] |
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E1.00124: Interactions of Bright Matter-Wave Solitons with a Barrier Potential Paul Dyke, Lei Sidong, Scott Pollack, Dan Dries, Randy Hulet Nondispersive solitary waves (solitons) can be produced in a one-dimensional Bose-Einstein condensate (BEC) with weak attractive interactions. We have created bright matter-wave solitons with $N\sim2\times10^5$ ultracold $^7$Li atoms by tuning the scattering length to small negative values via the broad $|1,1\rangle$ Feshbach resonance. In this work, we study the interaction between a kicked soliton and a thin barrier potential generated by a near-resonant cylindrically focused laser beam. Our results show that by varying the soliton kinetic energy, as well as the potential strength, it is possible to reflect, transmit, or even split the soliton. We investigate the possibilities for creating a matter-wave beamsplitter and a matter-wave interferometer by examining the recombination of the solitons. Theory has shown that in certain cases the solitons behave as single quantum mechanical object that may split into a Schr\"{o}dinger cat state. [Preview Abstract] |
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E1.00125: Loading an Inductively Coupled Ring Trap Paul Griffin, Aline Dinkelaker, Matthieu Vangeleyn, Aidan Arnold, Erling Riis We report on experimental progress towards an atom--interferometry experiment in a smooth ring geometry. We have proposed a new form of toroidal trap for ultra-cold and quantum degenerate atomic gases. By applying a time-varying magnetic field about an electrically isolated conducting loop a stable, time-averaged minimum of the magnetic field is formed from the superposition of the applied and induced fields. This geometry resolves the issue of perturbations of the ideal symmetry of the toroidal geometry due to electrical connections and benefits from time averaging of corrugating potentials due to current meandering. We present the status of a new experimental apparatus to use Bose ($^{87}$Rb) and Fermi ($^{40}$K) degenerate gases for Sagnac interferometry. We describe the procedure for loading an ultra-cold cloud of atoms into the trapping potential through a moving molasses in a magnetic field. Our laser system for cooling of K and its integration into the project are discussed, along with future development of the project. [Preview Abstract] |
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E1.00126: Atom interferometry with large momentum transfer PeiChen Kuan, Shau-Yu Lan, Brian Estey, Holger M\"uller The sensitivity of light-pulse atom interferometers can be greatly improved by large momentum transfer (LMT) beam splitters and long interrogation times. Large momentum space separation $\Delta p$ between two interferometric arms result in an increased phase shift proportional to $\Delta p$ or even $(\Delta p)^2$, and therefore leads to superior tools for precision measurements. ``BBB'' beam splitters, using high order Bragg diffraction combined with Bloch oscillations, have already been demonstrated and are scalable, as their momentum transfer is not limited by the available laser power. By running an additional conjugate interferometer at the same time, noise common to both interferometers can be eliminated. We will present our work aiming at further improvements, which would allow applications requiring extremely large enclosed areas, such as test of the Einstein equivalence principle, measurements of fundamental constants, or searching for new gravitational effects. [Preview Abstract] |
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E1.00127: Area Chirping and Gaussian Scattering in Atomic Coupled Ring Sagnac Interferometers John Toland, Christopher Sorrentino, Christopher Diggins, Christopher Search The impetus to measure inertial rotations via the Sagnac Effect in atomic interferometers arises from the potential $10^{10}$ enhancement of the rotational phase shift in comparison to their optical counterparts. We simulate ballistic transport of atomic matter waves in a one dimensional chain of N coherently coupled ring shaped atom interferometers in the presence of an inertial rotation of angular frequency, $\Omega$. The interference pattern in the transmission of the atoms through the interferometer chain as a function of the Sagnac phase shift has large transmission stopgaps interspersed with regions of near unity transmission. The transition from the stopgaps to unity transmission is characterized by a series of N narrow transmission resonances. We apply a chirp, a systematic symmetric change in the circumference of the individual rings from both edges towards the center to our chain of ring interferometers. We show that the first transmission peak moves into the stopgap and decreases in width indicating a higher sensitivity to inertial rotations.In addition we develop a numerical model to determine the effect that phase destroying Gaussian scatterers, located in one arm of each ring of the array, have on the transmission interference pattern through the chain. [Preview Abstract] |
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E1.00128: A Dual-Condensate Interferometer for Vibration-Free Measurements R.H. Leonard, R.A. Horne, C.A. Sackett A generic problem with atom interferometry is a high sensitivity to vibrational noise. In particular, the low frequency vibrations associated with building, traffic, and seismic activity can be very difficult to isolate, and can limit the usable measurement time of the interferometer. An alternative solution is to simultaneously implement two interferometers in the same apparatus, such that the vibrational noise is common mode but the signal to be measured is not. The difference in phase measured between the two interferometers then provides a signal measurement that is independent of the noise. This technique has previously been implemented effectively using non-condensed atoms for gravity gradiometry and rotational sensing. We present here a dual-interferometer scheme based on Bose-Einstein condensates confined in a linear magnetic guide. With only conventional vibration isolation, the coherence time of the interferometer is limited to about 70 ms, whereas (noisy) interference has been observed for up to 1 s. Current experimental results from the dual interferometer scheme will be presented, along with techniques for applying the scheme to various types of measurement. [Preview Abstract] |
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E1.00129: Numerical Study of an Atomic Delta Kicked Rotor Interferometer for Precision Measurements R.A. Horne, R.H. Leonard, C.A. Sackett The Atomic Delta Kicked Rotor (ADKR) consists of an otherwise free atom subjected to periodic standing wave laser pulses. It has been proposed that the ADKR system is well suited for metrology due to the sub-fourier scaling of its quantum resonances in the fidelity [1]. We have numerically investigated several different variations of fidelity-based interferometers, and studied applications to measurements of acceleration and recoil frequency. Sensitivity to errors such as fluctuations in the initial velocity, finite pulse duration, and laser amplitude noise were examined. In all cases considered, the sensitivity of the interference to the initial velocity presents a significant limit to the achievable resolution, even considering a condensate source with a velocity width limited only by the uncertainty principle. However, by using a small number of intense laser pulses, fairly high acceleration sensitivity ($10^{-5}g$) can in principle be obtained on a short time scale ($10^{-4}$~s). This could be useful for measurements requiring fast response times. \\[4pt] [1] P McDowall et al., New J. Phys. 11 123021 (2009); I.Talukdar et. al. Phys. Rev. Lett. 105, 054103 (2010). [Preview Abstract] |
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E1.00130: Interference, focusing and excitation of ultracold atoms M.C. Kandes, B.M. Fahy, S.R. Williams, C.H. Tally IV, M.W.J. Bromley One of the pressing technological challenges in atomic physics is to go orders-of-magnitude beyond the limits of photon-based optics by harnessing the wave-nature of dilute clouds of ultracold atoms. We have developed parallelised algorithms to perform numerical calculations of the Gross-Pitaevskii equation in up to three dimensions and with up to three components to simulate Bose-Einstein condensates. A wide-ranging array of the physics associated with atom optics-based systems will be presented including BEC-based Sagnac interferometry in circular waveguides, the focusing of BECs using Laguerre-Gauss beams, and the interactions between BECs and Ince-Gaussian laser beams and their potential applications. [Preview Abstract] |
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E1.00131: Towards a test of the universality of free fall using a $^6$Li-$^7$Li atom interferometer Dennis Schlippert, Geena Kim, Paul Hamilton, Holger M\"{u}ller We present a dual species guided matter-wave interferometer for performing a differential measurement of the acceleration of free fall for $^{6}$Li and $^{7}$Li atoms to test the universality of free fall (UFF). Use of this combination of atoms leads to a high sensitivity to new physics because of the relatively large difference difference between $^{6,7}$Li as compared with Be-Ti or $^{85,87}$Rb. An optical lattice will be loaded with $^{6}$Li and $^{7}$Li atoms from a dual species 2D/3D-magneto-optical trap. The lattice will then be employed both as a waveguide to prevent atom losses due to the high thermal velocity of Li and as large-momentum-transfer beam splitters in analogy to the Bloch-Bragg-Bloch beam splitters already developed by us~[1,2]. This allows for high sensitivies as the interferometer's phase shift scales as $k_{\rm{eff}}T^2$, where $\hbar k_{\rm{eff}}$ is the transferred momentum and $T$ the time of evolution between the beam splitters. We anticipate an accuracy of $10^{-14}g$ for the differential acceleration measurement. Systematic effects, in particular gravity gradients, are adressed in our design. Furthermore, novel cooling techniques for Li such as Raman sideband cooling are investigated.\\[4pt] [1] H. M\"{u}ller et al., Phys. Rev. Lett. {\bf 100}, 180405 (2008)\\[0pt] [2] H. M\"{u}ller et al., Phys. Rev. Lett. {\bf 102}, 240403 (2009) [Preview Abstract] |
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E1.00132: Atomic beam velocity measurements using phase choppers in an atom interferometer Ivan Hromada, William Holmgren, Catherine Klauss, Alexander Cronin We introduce a novel technique to measure the velocity of atoms in an atom beam interferometer. This technique uses pulsed electric fields from two phase choppers to induce $\pi$ phase shifts for the atomic de Broglie waves. We find the atom beam velocity by measuring the amplitude and phase of the interference pattern as a function of pulse timing. We have demonstrated measurements of mean velocity with a precision of 0.1\%, and measurements of velocity spread with a precision of 5\%. This new technique directly supports high-precision measurements of atomic polarizability that we are conducting in the same atom beam interferometer apparatus. [Preview Abstract] |
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E1.00133: CONTROL OF QUANTUM DYNAMICS |
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E1.00134: Supersymmetric Mechanism for Inversionless Property of n/cosh(t) Laser Pulse Andrew Koller, Maxim Olshanii It is known that a two-level atom subjected to a laser pulse of the form $V(t) = V_0/\cosh(\alpha t)$ has the rare property that, for a discrete series of pulse heights, it shows no transfer of population between the levels, for any detuning of the pulse from resonance.\footnote{V. M. Akulin, ``Coherent Dynamics of Complex Quantum Systems'' (Springer, Heidelberg, 2006).} In particular, pulses of the form $V(t) = \hbar \alpha n/\cosh(\alpha t)$ (with $n$ an integer) have this inversionless property. We show that the problem is analogous to reflectionless scattering in a stationary wave problem, and is linked to a potential-free Hamiltonian via a quantum-mechanical supersymmetric (QM SUSY) chain. We also explore the connection between this supersymmetric chain and the multi-soliton solutions of the sine-Gordon equation. [Preview Abstract] |
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E1.00135: Fidelity Between Unitary Operators and the Generation of Robust Gates Renan-Andres Cabrera-Lafuente We present some results concerning the Dyson series and the Magnus expansion for the fidelity of unitary operators and its applications for finding robust quantum gates. An illustrative case is shown for the case of a qubit with off-resonance perturbations. [Preview Abstract] |
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E1.00136: Quantum calculations of spin-1 squeezing at finite magnetic field Chris Hamley, Corey Gerving, Thai Hoang, Michael Chapman We investigate spin mixing in a finite magnetic field theoretically using numerical integration of Fock states for a tri-diagonal Hamiltonian as well as the Q-representation of the coherent (mean-field) states. We identify approximate SU(2) subspaces of the SU(3) system and compare them to previous theoretical work. We also compare the results of this simulation to recent experimental measurements. [Preview Abstract] |
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E1.00137: Two-species Coherent Transport Adiabatic passage and Quantum Gate implementation in an Optical Superlattice Kunal Das, Miroslav Gajdacz, Tomas Opatrny In an optical super-lattice of triple wells, containing two mutually interacting atom species in every cell, we show that one species (A) can be transported from the left well to the right well without ever significantly occupying the central well. This occurs simultaneously in every unit cell in the lattice. We demonstrate that this can be achieved with or without the presence of an atom of the second species (B) in the intermediate well of each cell, thereby allowing species-selective transport that avoids spatial overlap and direct interaction among the two species. Furthermore, by using optimal quantum control, we also demonstrate the lattice-wide parallel implementation of CNOT quantum gates in this configuration by using the presence or absence of an atom B in the central well of each cell as a control bit, and the localization of an atom A in the left well or the right well as the target bit. [Preview Abstract] |
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E1.00138: QUANTUM INFORMATION |
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E1.00139: Ultracold Atoms and Cavity Quantum Electrodynamics: Building a Resource for Quantum Information Kyle Arnold, Markus Baden, Murray Barrett We report our progress towards an atom-photon node using cavity QED. Our system utilizes a far detuned optical lattice to transport cold atoms into a high finesse cavity, anywhere from a single atom to several thousand. We will present our ongoing investigations with this system. In particular we have studied effect of varying coupling on the cavity spectrum with multiple hyperfine levels. [Preview Abstract] |
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E1.00140: Quantum information experiments with a micro-fabricated, cryogenic, surface-electrode ion trap A.C. Wilson, K.R. Brown, C. Ospelkaus, Y. Colombe, D. Leibfried, D.J. Wineland Although the basic components of a quantum information processor using trapped ions have been demonstrated, scaling to large numbers of qubits and operations so that algorithms and simulations of practical importance can be implemented remains a major challenge. This is technically challenging because it requires significant improvements in the precision with which quantum states of ions are prepared, manipulated and measured. Solutions are multi-disciplinary - involving micro-fabrication, cryogenics, integrated photonic devices, as wells as materials and surface science. Here we report progress from experiments that address a range of these issues. We use a micro-fabricated, cryogenic, surface-electrode ion trap, with two closely-spaced independently controlled potential wells. In the first experiment with this new apparatus, we implement a scheme for coupling two ions trapped in separate wells, and demonstrate tunable energy exchange at approximately the single quantum level. A second experiment investigates errors in single qubit gates (rotations) with the use of randomized bench-marking. [Preview Abstract] |
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E1.00141: Towards scalable quantum simulation of spin models with trapped ions E.E. Edwards, R. Islam, S. Korenblit, K. Kim, M.-S. Chang, C. Monroe, G.-D. Lin, L.-M. Duan, C. Noh, H. Carmichael, C.-C. Wang, J. Freericks We simulate the long-range transverse field Ising model using a collection of trapped ions. The phase diagram contains features such as quantum phase transitions and first order transitions due to frustration. In order to extend this quantum simulation to larger systems and other spin models, we must understand and minimize errors. One of the primary sources of error is unwanted scattering due to spontaneous emission and can be reduced by engineering the Hamiltonian using a far-detuned, pulsed laser system. This improvement paves the way for experiments with a greater number of spins where classical simulations of certain forms of the Ising model become intractable. This work is supported by grants from the U.S. Army Research Office with funding from the DARPA OLE program, IARPA, and the MURI program; the NSF PIF Program; the NSF Physics Frontier Center at JQI; and the European Commission AQUTE program. [Preview Abstract] |
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E1.00142: Microwave Near-Field Quantum Control of Trapped-Ion Qubits U. Warring, C. Ospelkaus, K.R. Brown, Y. Colombe, J.M. Amini, D. Leibfried, D.J. Wineland A major concern in the development of a future quantum processor is the scalability toward large numbers of qubits; its structure should enable one- and multi-qubit gates on arbitrarily selected qubits. As for a classical processor, micro fabrication might lead to a promising route to build such a versatile ion-qubit quantum processor. Recent experiments with surface electrode ion traps have demonstrated the key ingredients for scalable ion loading, transporting, and trapping architecture. Here, we present an approach to incorporate also the ion-qubit manipulation into the surface-electrode structure.\footnote{C. Ospelkaus, \textit{et al.} Phys. Rev. Lett. 101, 090502 (2008).} It is based on an oscillating magnetic field generated by microwave currents in electrodes of a micro fabricated surface-electrode trap. The homogeneous field component is used to implement single-qubit gates, while the field gradient leads to a coupling of the ions internal and motional states. With further improvements, this coupling can be deployed to entangle multi-qubits. [Preview Abstract] |
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E1.00143: Coherent control of neutral atoms on chip traps using optical frequency combs Qudsia Quraishi, Vladimir Malinovsky, Jason Alexander, Violeta Prieto, Chris Rowlett, Patricia Lee Optical frequency combs (OFCs), emitted by ultrafast modelocked pulsed lasers, are excellent tools to perform quantum coherent control. The spectral purity, large bandwidth and high pulse powers makes these sources attractive for precision control of multi-level atoms. Recent experiments have shown that an OFC can be used to coherently control and entangle trapped ion qubits by means of off-resonant Raman transitions [1]. Here, we propose to extend this technique to neutral atoms confined on an atom chip and we also propose to implement an all-optical technique for hyperfine qubit manipulation using OFCs. We envisage using pairs of OFC modes to drive stimulated Raman transitions between the two hyperfine clock states of 87Rb confined on an atom chip. The Raman transitions will be driven using a four photon technique whereby the first photon pair drives off-resonantly to the intermediate state 2S1/2 |F=2, mf=0$>$ and then a second photon pair resonantly drives to 2S1/2 |F=2, mf=+1$>$. Co-propagating Raman fields impart only a spin flip whereas non-copropagating fields transfer two photon recoil momentum to the atoms, thus entangling the internal spin with the external motion of the atoms. We plan on using the frequency comb to impart state dependent forces to the atomic cloud. [Preview Abstract] |
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E1.00144: Motional Broadening in Ensembles With Heavy-Tail Frequency Distribution Yoav Sagi, Rami Pugatch, Ido Almog, Nir Davidson, Michael Aizenman Motional narrowing is a well-known phenomenon in which the spectrum is narrowed because the frequency of each particle in the ensemble is fluctuating. Motional narrowing was observed in many physical systems, ranging from liquid NMR [1] to cold atomic ensembles [2]. Here we show that fluctuations can actually have the reverse effect and lead to broadening of the spectrum. We prove that the condition for this to happen is that the ensemble frequency distribution will have heavy tails with a diverging mean. We also show that for both motional narrowing and broadening the asymptotic decay of the coherence in exponential, and derive an expression for the decay rate. Finally, we study a scenario with a cutoff in the frequency distribution heavy-tail and find that motional broadening still persists up to some fluctuation rate. \\[4pt] [1] Bloembergen, N., Purcell, E. M., and Pound, R. V. Phys. Rev. 73, 679 (1948). \newline [2] Sagi, Y., Almog, I., and Davidson, N. Phys. Rev. Lett. 105, 093001 (2010). [Preview Abstract] |
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E1.00145: An open-system quantum simulator with trapped ions Julio T. Barreiro, P. Schindler, D. Nigg, T. Monz, M. Chwalla, M. Hennrich, M. M\"uller, P. Zoller, C.F. Roos, R. Blatt We present the realization of an experimental toolbox for simulating an open quantum system with up to five qubits by engineering the multi-qubit dynamics through a controlled coupling to an environment. Using a quantum computing architecture with trapped ions, multi-qubit gates are combined with optical pumping to implement coherent operations and dissipative processes. We illustrate this engineering by the dissipative preparation of entangled states, the simulation of coherent many-body spin interactions, and the quantum non-demolition measurement of multi-qubit observables. Our toolbox represents a conceptual step towards the realization of an open quantum system simulator with applications in various fields, including condensed-matter physics and quantum chemistry, possibly in modeling quantum effects in biology, and in quantum computation driven by dissipation. [Preview Abstract] |
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E1.00146: Quantum Manipulation of an Ion Coupled to an LC Circuit Dvir Kafri, David Kielpinski, Gerard Milburn, Jacob Taylor Although ion traps have several advantages as media for quantum simulation, interacting ions in different traps at a quantum mechanical level remains difficult. As a hybrid' solution to this challenge, we present a technique for coupling the spin of an individual ion to the mode of a nearby LC circuit. The circuit mode is engineered to be comparable to the spin splitting, which is on the order of GHz. In the spirit of the Molmer-Sorenson gate, the desired ``phonon-mediated'' coupling is achieved by driving interactions with the ion's radio frequency vibrational mode. We show how the spin-circuit coupling can be used to generate arbitrary, spin-dependent displacements of the circuit mode. In conjunction with quantum nondemolition measurements, these displacements can be used to coherently transfer information between the two degrees of freedom. Finally, we show how interactions with the ion can be used to generate squeezed states of the LC mode, and discuss the limits of this squeezing due to noise losses and nonlinear corrections. [Preview Abstract] |
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E1.00147: Sympathetic Heating Spectroscopy with atomic sideband measurement Craig Clark, James Goeders, Grahame Vittorini, C. Ricardo Viteri, Kenneth Brown The idea of transferring information between multiple trapped atomic ions is a common and necessary practice in Quantum Information Processing (QIP). We have developed a technique which takes advantage of the Coulombic coupling used in QIP to acquire spectroscopic information of a trapped ion. Sympathetic Heating Spectroscopy (SHS) works through a two-step process in which we heat the two ion Coulombic crystal via the spectroscopy ion, and then obtain spectroscopic information by observing changes in fluorescence of the control ion as the system is recooled. We initially used two different isotopes of calcium in the incoherent regime of Doppler recooling, and are extending the method to look at a middle ground between SHS and Quantum Logic Spectroscopy (QLS) where atomic sidebands are used to determine the temperature. The main difference between QLS and the new method is that it is unnecessary to have coherent control of the spectroscopy ion. Measurements showing the improved sensitivity using atomic sidebands and preliminary results for replacing the atomic spectroscopy ion with a molecular ion will be presented. [Preview Abstract] |
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E1.00148: Topologically Protected Quantum State Transfer Norman Yao, Chris Laumann, Liang Jiang, Alexey Gorshkov, Hendrik Weimer, Ignacio Cirac, Mikhail Lukin Quantum state transfer between distant qubits forms an essential ingredient of any scalable quantum information processor. We propose and analyze a novel approach for quantum state transfer between remote spin qubits mediated by the edge mode of a chiral spin liquid. In previous approaches, the fidelity of quantum state transfer depends sensitively on disorder-induced eigenstate localization. To overcome this sensitivity to disorder, we investigate the topologically non-trivial phase of an exactly solvable 2D spin Hamiltonian, ultimately demonstrating the possibility of achieving robust, topologically protected quantum state transfer through the associated edge mode. Realistic imperfections, decoherence effects and generalizations are discussed. [Preview Abstract] |
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E1.00149: Pulsed laser gates for trapped atomic qubits Crystal Senko, Wesley C. Campbell, Jonathan Mizrahi, Chris Monroe Current experimental techniques for entangling multiple trapped ion qubits via the quantized modes of motion are inherently limited in speed and thus sensitive to many sources of noise. We use high power mode-locked lasers to perform ultrafast qubit operations via stimulated Raman transitions. We show that complete control over the spin state of a single qubit can be accomplished in tens of picoseconds by splitting a single pulse and varying the delay [1]. We also investigate improvements to the fidelity of current protocols using a weak pulse train at a large (33 THz) detuning [2]. Future work will focus on generating entangling gates on timescales faster than a motional period, by tailoring the ions' motional evolution with pulse sequences of varying Rabi frequency [3] or using spin-dependent momentum kicks fashioned from a few strong pulses [4,5]. [1] W.C. Campbell et al., PRL 105, 090502 (2010) [2] D. Hayes et al., PRL 104, 140501 (2010) [3] S.-L. Zhu et al., Europhys. Letters 73, 485 (2006) [4] J.J. Garcia-Ripoll et al., PRL 91, 157901 (2003) [5] L.-M. Duan, PRL 93, 100502 (2004). [Preview Abstract] |
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E1.00150: Linear Ion Chains in Silicon Surface-Electrode Traps S. Charles Doret, Jason Amini, Ken Wright, Arkadas Ozakin, Curtis Volin, Alexa Harter, Richart Slusher Long chains of equally spaced ions provide an environment for quantum information processing that may be extendable to large- scale quantum information processing and quantum simulation. Such chains may be stably held in tailored anharmonic potentials, a task for which linear surface-electrode traps with many DC electrodes are ideally suited. Here we report progress towards experiments with chains of $^{40}$Ca$^+$ and $^{44}$Ca$^+$, such as splitting and merging of sub-chains, deterministic loading of particular ion- isotope sequences, and measurements of heating and thermalization of ion chains of various lengths. [Preview Abstract] |
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E1.00151: Plug-and-Play Planar Ion Traps for Scalable Quantum Computation and Simulation Jason Amini, Douglas Denison, S. Charles Doret, Daniel Faircloth, Harley Hayden, Tyler Killian, David Landgren, Kevin Martin, True Merrill, Arkadas Ozakin, C. S. Pai, Fayaz Shaikh, Chris Shappert, Curtis Volin, Ken Wright, Alexa Harter, Richart Slusher At the heart of most ion-based quantum information processing and simulation efforts is an RF-Paul trap to confine the ion qubits. Cutting edge experiments are transitioning from a few qubits to a few tens of qubits with many more qubits envisioned for the future. The underlying ion traps need to both grow with the experiments and provide additional features that can simplify and extend these experiments. The Georgia Tech Research Institute (GTRI) is developing modeling and fabrication processes for these new generations of ion traps using silicon VLSI technology in surface- electrode geometries. Verified by detailed in-house trap characterization, GTRI has fabricated traps that approach the plug- and-play ideal and demonstrate reliable ion loading and transport, long dark lifetimes, and stable ion chains. Additional features are in development including junctions, integrated GHz range current guides for global qubit rotations, and micromirrors for light collection. [Preview Abstract] |
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E1.00152: Coupling of NV centers to microscopic cavities Y. Chu, E. Togan, M. Goldman, A. Kubanek, A. Zibrov, M. Lukin Recently there has been a great interest in using individual nitrogen vacancy centers in diamond in a quantum optics context. For instance, the light-matter quantum interface achievable with an NV center at low temperatures has been used to coherently manipulate NV degrees of freedom [1], as well as to entangle the electronic spin of a single NV center with a photon [2]. However, for most applications low collection efficiency of photons out of the NV center imposes a significant limit. To solve this problem, the NV center has been integrated into different photonic structures, where the coupling of the NV center to a single cavity mode is enhanced [3, 4]. Here, we show progress towards integrating NV centers, in a thin ($\sim $20$\mu $m) bulk diamond, with a microscopic cavity, which consists of two mirrors and has a small mode waist of $\sim $ 5$\mu $m. This approach has the advantage of using both a high quality single crystalline bulk diamond that contains NVs with good optical properties, and an independently optimized cavity design. This method should drastically increase the rate at which entangled photons may be obtained from single NV centers and hence should allow remote NV based quantum nodes to be connected by the photons that are emitted by the NVs. In the future, a strong interaction of the light field with a single solid-state emitter could open the field of cavity quantum electrodynamics to a new, scalable quantum system.\\[0pt] [1] B. Buckley, et al., Science 330, 1212-1215 (2010). [2] E. Togan, et al., Nature 466, 730-734 (2010). [3] D. Englund, et al., Nano Lett. 10, 3922 (2010). [4] A. Faraon, et al., arXiv:1012.3815 (2010). [Preview Abstract] |
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E1.00153: Photonic quantum information processing: generalized concurrence of multimode photonic states Dmitry Uskov The first theoretical proposal of implementing measurement-induced photonic gates was limited to controlled-NOT gates of perfect fidelity (Knill et al, Nature 46-52 (2001)). Recent work on numerical optimization of such gates allowed to extend this method to tree-qubit gates and to find optimal schemes for generic two-qubit entangling gates (Uskov et al, Phys. Rev. A \textbf{81}, 012303 (2010)) Since straightforward numerical simulations in quantum information theory are inherently limited to low-dimensional cases, we develop and exploit a group-theoretical method of constructing generalized multivariable concurrence of multimode multiphoton states. As an application, we perform analysis of success probability of photonic gates with compromised fidelity. Implications of these results for photonic cluster state generation/computation are discussed. [Preview Abstract] |
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E1.00154: QUANTUM MEASUREMENT |
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E1.00155: Tamper-indicating Quantum Optical Sensing Travis Humble, Duncan Earl, Warren Grice Monitoring systems based on fiber-optic seals actively monitor inventories of closed containers for tampering. However, the physics underlying these tamper-indicating optical systems make them susceptible to deception. The basis for this deception lies in the description of the electromagnetic field transmitted through the fiber. Within classical physics, knowledge of the light source, e.g., carrier frequency and pseudo-random modulation, can be used by an intruder to replicate the transmission. Once a replicated field is injected into the fiber, the downstream detector cannot discriminate it from the original transmission. Motivated by this context, we demonstrate a quantum optical, tamper-indicating device inherently immune to replication. We use time-bin entanglement (TBE) distributed through a pair of fibers, where each fiber couples to a Mach-Zehnder interferometer (MZI) detector. We monitor coincident detection as a function of the combined MZI phase $\phi = \phi_{1} + \phi_{2}$ to statistically quantify entanglement in terms of TBE visibility. The presence or absence of the expected interference consequently serves as a test for tampering, and we quantity the probability of detection and false alarm using this statistic. We anticipate this form of quantum-based sensing to support future intrusion detection technologies. [Preview Abstract] |
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E1.00156: Highly Efficient State-Selective Submicrosecond Photoionization Detection of Single Atoms Markus Weber, F. Henkel, M. Krug, J. Hofmann, W. Rosenfeld, N. Ortegel, H. Weinfurter One crucial requirement for quantum computation, quantum communication, and quantum metrology is the highly efficient measurement of qubit states. For atomic qubits, the most frequently used fluorescence method allows measuring with a detection efficiency of almost unity, however, at the cost of comparably long detection times ($>$100 $\mu $s). Here we experimentally demonstrate an alternative detection scheme suitable for state analysis of single optically trapped atoms in less than 1 $\mu $s with an overall detection efficiency $\eta $ exceeding 98{\%} [1]. The method is based on hyperfine-state selective photoionization and subsequent registration of the correlated photoionelectron pairs by coincidence counting via two opposing channel electron multipliers. The scheme might be a key ingredient for future quantum information applications or precision spectroscopy of ultracold atoms. It might thus be applied, e.g., for imaging and site-specific readout of atoms in optical lattices, for in situ, real-time probing of ultracold atomic ensembles with sub-Poissonian accuracy, or as detector for a loophole-free test of Bell's inequality with a pair of trapped atoms at remote locations [2]. [1] F. Henkel et al., PRL 105, 253001 (2010). [2] J. Volz et al., PRL 96, 030404 (2006). [Preview Abstract] |
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E1.00157: Quantum Measurements Using Electron-Multiplying Charge-Coupled Devices (EMCCDs) Jonathan Mackrory, Jeremy Thorn, Daniel Steck We outline the possibilities of realizing the Heisenberg microscope with a modern electron-multiplying charge-coupled device (EMCCD) camera. In particular, we assume we are imaging a single atom illuminated by resonant light using an EMCCD camera. The measurement from imaging the scattered light allows an observer to update their state for the atom's location using Bayesian estimation. The observer updates their state for the atom by continuously integrating a stochastic master equation (SME). We present a model of the inefficiencies and noise sources in an EMCCD camera, and use this model to derive an SME and integration method that incorporates the information from the imaging camera. Finally, we fit our model of an EMCCD to some commercially available EMCCD cameras, and use the fit parameters to evaluate the feasibility of this experiment. [Preview Abstract] |
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E1.00158: Faraday rotation spectroscopy in multi-pass atomic vapor cells Shuguang Li, Pranjal Vachaspati, Nezih Dural, Michael Romalis Many important applications of atomic vapors, such as quantum measurements, light storage experiments, and atomic magnetometers benefit from large optical depth of the atomic ensemble. We explore multi-pass cells using cylindrical mirrors with a hole for the entrance and exit of the laser beam to achieve very high optical depth while sampling a large number of atoms. Such cells are much less sensitive to mirror quality and alignment compared to optical cavities and do not require laser frequency locking, mode matching or power coupling matching. Cells with more than 100 passes have been fabricated using internal high-reflectivity mirrors. We have performed paramagnetic Faraday rotation measurements on Rb vapor and have observed atomic rotation angles in excess of 60 radians. Quantum spin noise from unpolarized atomic vapor has also been observed with a high signal-to-noise ratio. This system also exhibits non-linear spin relaxation due to spin-exchange collisions, opening the possibility of using spin-squeezing techniques to improve long-term sensitivity of frequency measurements. We will report on the development of a scalar atomic magnetometer using such spin-squeezing techniques. [Preview Abstract] |
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E1.00159: QUANTUM CRYPTOGRAPHY AND COMMUNICATION |
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E1.00160: A BEC as a quantum memory for the polarisation of light Stefan Riedl, Matthias Lettner, Christoph Vo, Simon Baur, Stephan D\"{u}rr, Gerhard Rempe The polarisation of light is a much-used workhorse in quantum cryptography and quantum-information applications. We experimentally realise a quantum memory for arbitrary polarisation states of a light pulse, using an atomic multilevel scheme and electromagnetically induced transparency (EIT) in a Bose-Einstein condensate (BEC). In the experiment, the energy of the retrieved light pulse reaches values as high as 50\% of the incoming light pulse. Furthermore, the observed fidelity of the polarisation state after the readout reaches values up to 99\%. [Preview Abstract] |
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E1.00161: Entanglement of Light-Shift Compensated Atomic Spin Waves with Telecom Light Yaroslav Dudin, Alexander Radnaev, Ran Zhao, Jacob Blumoff, Brian Kennedy, Alex Kuzmich Long-lived quantum memories interfaced with photonic qubits at telecom wavelengths are the key elements for quantum repeater based long distance quantum telecommunication. We report the observation of Bell's inequality violation (S = 2.66+/-0.09) for a photonic polarization qubit at 1.37 $\mu $m wavelength and a rubidium spin-wave qubit stored in a Stark decoherence free optical lattice for 10 ms. We also observed a violation of Bell's inequality (S = 2.65+/-0.12) for a spin-wave qubit entangled with 795 nm light polarization qubit, for 0.1 s storage time. A light qubit at 1.37 $\mu $m is generated from 795 nm polarization qubit via an efficient frequency conversion process in an auxiliary cold rubidium sample. [Preview Abstract] |
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E1.00162: EXOTIC ATOMS AND MOLECULES |
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E1.00163: Weakly-Bound Bosonic States in the Strongly Interacting Regime Javier von Stecher Among the most striking features of ultracold few-body physics is the universal behavior that allows the characterization of physical phenomena through a handful of parameters. In both 2D and 3D, the determination of universal behavior is challenging, and studies have mainly focused on few-body systems with up to four particles. Here, we analyze the behavior of weakly-bound bosonic states in the strongly interacting regime in two and three dimensions extending, the calculations up to N=6. Combining a correlated Gaussian basis set expansion with a complex scaling method; we extract the energy, resonances, and structural properties of bosonic system for different two-body potentials. Our calculations show a rich structure of bosonic cluster states whose analysis allows us to identify universal phenomena in two and three dimensional systems with N$>$4. Finally, we discuss the manifestation of these universal states in experiments with ultracold gases. [Preview Abstract] |
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E1.00164: On recent discovery of new planetoids in the solar system and quantization of celestial system V. Christianto, Florentin Smarandache The present note revised the preceding article discussing new discovery of a new planetoid in the solar system. Some recent discoveries have been included, and its implications in the context of quantization of celestial system are discussed, in particular from the viewpoint of superfluid dynamics. In effect, it seems that there are reasons to argue in favor of gravitation-related phenomena from boson condensation. [Preview Abstract] |
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E1.00165: Experiment at NIST to produce one-electron ions in circular Rydberg states Joseph Tan, Samuel Brewer, Nicholas Guise Highly charged ions, including bare nuclei, produced in the NIST EBIT (electron beam ion trap) are extracted and captured in the simplest Penning trap that can be configured with a single neodymium (NdFeB) magnet.\footnote{N. Guise, S.M. Brewer and J.N. Tan, oral presentation at this meeting} Slowing and capture of bare nuclei is a step towards formation and study of one-electron ions within the well-controlled environment of a Penning or Paul trap. Detailed laser spectroscopy of hydrogen- like ions in circular Rydberg states would potentially provide a test of theory in a regime with completely negligible nuclear- size corrections.\footnote{U.D. Jentschura, \textit{et al.}, Phys. Rev. Lett. \textbf{100}, 160404 (2008).} Such a test is of particular interest in the wake of the large discrepancy in proton radius determinations that resulted from the muonic hydrogen Lamb-shift measurements.\footnote{R. Pohl, \textit{et al.}, Nature \textbf{466}, 213-218 (2010).} We discuss some experiments with captured ions planned in a more elaborate apparatus configured with a two-neomagnet (NdFeB) Penning trap for better magnetic field homogeneity, an electron gun for in- trap loading of low-$Z$ ions, and optical access for spectroscopy experiments with low-energy, highly-charged ions. [Preview Abstract] |
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E1.00166: ABSTRACT WITHDRAWN |
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E1.00167: NONLINEAR DYNAMICS |
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E1.00168: Microwave De-excitation schemes for Rydberg Hydrogen Atoms Luca Perotti, Daniel Vrinceanu Control of Rydberg atom wavefunctions has evolved from static or periodic protocols to transport ones, exploiting either modulation or chirping of the controlling periodic field. Applications vary from quantum computing schemes using excitation blockades to the production of anti-hydrogen atoms in Penning traps. Theoretical studies have essentially been limited to 1-D models. Applications such as the production of anti-hydrogen atoms mentioned above, instead require the study of some 3D statistical ensemble of orbits. Our preliminary numerical 3D studies show that chirping of the microwave field is most effective in de-exciting atoms that are almost one dimensional, as transport terminates when the two parabolic quantum numbers are equal, thus seriously limiting its efficiency for initial states which are not almost 1D. Alternative approaches are suggested. [Preview Abstract] |
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E1.00169: Observation of the instantaneous velocity of a Brownian Particle Simon Kheifets, Tongcang Li, David Medellin, Mark Raizen A notable feature of Brownian motion is that it is self-similar for all time scales. However, at short enough time scales, a particle at thermal equilibrium follows straight line trajectories with a well-defined velocity. The time scale at which the transition occurs between ballistic and Brownian motion is set by the momentum relaxation time, $\tau_p$. We have measured the position of an optically trapped particle in air with temporal resolution much faster than $\tau_p$, and have thus observed the transition between ballistic and diffusive Brownian motion and measured the instantaneous velocity of a Brownian particle for the first time. This has allowed us to directly verify the energy equipartition theory for Brownian motion. We are currently working towards observing the instantaneous velocity of a particle in water, for which $\tau_p$ is several orders of magnitude smaller. [Preview Abstract] |
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E1.00170: Generation of microjoule tunable infrared pulses through DFG with BBO crystal Baozhen Zhao, Kun Zhao, Sabih Khan, Cheng Yan, Zenghu Chang A broadband tunable infrared pulse was generated through different frequency mixing, by a ultrashort 800nm pulse with 8fs, 1kHz, 400uJ out of a Ne hollow-core fiber and chirped mirror compressors, with 3mm BBO type II phase matching. The energy of infrared pulse is about 3uJ, spectral bandwidth is around 300nm, with tunable central wavelength range from 1800nm to 2300nm. The corresponding transform-limited pulse is $\sim $26fs. It can be compressed with CaF2 prism pair. The streaking effect in an attosecond streak camera for characterizing isolated attosecond XUV pulses is stronger, if the streaking laser has a longer wavelength. Therefore, the generated short laser pulse with a central wavelength near 2um is an excellent candidate of the streaking laser in an attosecond streak camera. [Preview Abstract] |
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E1.00171: Hamiltonian monodromy Chen Chen, Megan Ivory, Seth Aubin, John Delos We say that a system exhibits monodromy if we take the system around a closed loop in its spectrum space, and we find that the system does not come back to its original state. We report a method for experimental realization of a newly discovered dynamical manifestation of monodromy by investigating the behavior of atoms in a trap. The trapping potential has long range attraction to and short range repulsion from the center. Calculations include two parts. First, we consider atoms as classical particles for which we can choose any desired set of initial conditions. As was shown previously for different systems, when we take the system around a monodromy circuit, a loop of initial conditions evolves into a topologically different loop. Second, we incorporate the limitations that would appear in experimental implementation. The atoms have a range of initial angles, initial angular momenta, and initial energies. Our work shows how real atoms can be driven by real forces around a monodromy circuit, and thereby shows how one can observe dynamical monodromy in a laboratory. Finally, we extend classical dynamical monodromy to quantum dynamical monodromy by examining wave function evolution under comparable conditions. [Preview Abstract] |
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E1.00172: NEW THEORETICAL METHODS |
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E1.00173: A Field Theory Approach to Roughness Corrections for Casimir Energies Hua-Yao Wu, Martin Schaden We present a systematic approach to the interaction of a massless scalar field with stochastically rough parallel plates by deriving an effective brane-like field theory in which a massless scalar field living in four-dimensional Euclidean space-time couples to a scalar (roughness) field restricted to one of the two-dimensional plates. The model is described by the interaction $V_{int} =\textstyle{1 \over 2}\varphi ^2(\tau ,z,x_\bot )[g_1 \delta (z-a-h(x_\bot ))+g_2 \delta (z)]$ with prescribed (measured) correlations for the roughness field $h(x_\bot )$ summarized by a generating functional. Counterterms ensure that the correlations of the roughness-field $h(x_\bot )$ do not depend on the separation $a$ of the plates. We in particular demand that$\left\langle {h(x_\bot )} \right\rangle =0\mbox{ and }\left\langle {h(x_\bot )h(y_\bot )} \right\rangle =\sigma ^2\exp (-{(x_\bot -y_\bot )^2} \mathord{\left/ {\vphantom {{(x_\bot -y_\bot )^2} {\ell ^2}}} \right. \kern-\nulldelimiterspace} {\ell ^2})$. Here $\sigma ^2$ and $\ell $ are parameters related to the variance and correlation distance of the surface roughness. The leading roughness correction to the Casimir energy is given by a two-loop contribution to the free energy. Our results are compared with those of other perturbative methods for taking stochastic roughness into account. We use renormalization group methods to examine the strong coupling (Dirichlet) limit of this model. [Preview Abstract] |
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E1.00174: Explorations into quantum state diffusion beyond the Markov approximation Curtis J. Broadbent, Jun Jing, Ting Yu, Joseph H. Eberly The non-Markovian quantum state diffusion equation is rapidly becoming a powerful tool for both theoretical and numerical investigations into non-trivial problems in quantum optical QED. It has been used to rederive the exact master equation for quantum Brownian motion, as well as an optical cavity or a two-level atom which is either damped or dephased under the rotating wave approximation [1]. The exact quantum state diffusion equations for the spin-1 system have also been found [2], and general theorems have now been derived for solving the N-cavity, N-qubit, and N-level systems [3]. Here, we build upon the results of Ref.~[3] to explore other problems from quantum optical QED using the non-Markovian quantum state diffusion equation. [1] L. Diosi, N. Gisin, and W.T. Strunz, Phys. Rev. A {\bf 58}, 1699 (1998). T. Yu, L. Diosi, N. Gisin, and W. T. Strunz, Phys. Rev. A {\bf 60}, 91 (1999). [2] J. Jing and T. Yu, Phys. Rev. Lett. {\bf 105}, 240403 (2010). [3] J. Jing, X. Zhao, J. Q. You, and T. Yu, arXiv:1012.0364v1. Research supported by ARO W911NF-09-1-0385, NSF PHY-0855701, and NSF PHY-0925174. [Preview Abstract] |
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E1.00175: On the Systematic Error in the Quantum Mechanical Calculations to the Periodic Table of Elements Albert Khazan The scientists working on the problems of the Periodic Table of Elements regularly attempt to create models of the elements on the basis of the laws of Quantum Mechanics. One even attempted to use the calculation of the dependency ``atomic mass -- element's number'' on this basis, in order to extend the Table by introducing two new Periods containing 50 elements each. The hyperbolic law we have found in the Periodic Table allows to find, first, the atomic mass of the last (heaviest stable) element (411.66), then -- the number of the protons in it (155). Two functions were compared: the IUPAC 2007 function (elements 80-118) and another one created according the other data (elements 80-224). Both functions have a large deviation of data in No.104-118. Commencing in Period 8, there are three ``shifts'' of atomic mass for 17, 20, and 25 AMU. Also, our analysis manifests that there in all the aforementioned data is a single point with atomic mass 412 and number 155, where the parameters meet each other. This fact verifies our theory (Khazan A. Upper Limit in Mendeleev's Periodic Table -- Element No.155. 2nd ed., Svenska fysikarkivet, Stockholm, 2010). [Preview Abstract] |
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E1.00176: A New View of Minkowski Space, and its Effects in Relativistic Quantum Mechanics Felix T. Smith Since Minkowski in 1908 announced the merger of space and time there has never been an explanation of its real-and-imaginary structure ($x$,$y$,$z$,\textit{ict}). An explanation is now available that was unknown in 1908: The imaginary component in the 4-vector is a necessary consequence of negative curvature in the background position 3-space, and its time dependence comes from the changing curvature radius under the Hubble expansion in cosmic time (Smith, F. T., Ann. Fond. L. de Broglie [AFLB], \textbf{35}, in press, (2010)). These observations confirm an especially symmetric extension of special relativity previously reported (Smith, F. T., AFLB, \textbf{30}, 179, (2005)), based on a direct product of two Lorentz groups, one generated by velocity boosts and the other by translations in a Hubble-expanding hyperbolic position space. The symplectic symmetry of the direct product group makes it possible to extend a fully Hamiltonian dynamics and quantum mechanics smoothly throughout the relativistic regime. Some resulting changes in special relativity will be described, including fully covariant $n$-body relativistic Schr\"{o}dinger and Dirac equations. [Preview Abstract] |
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E1.00177: Dynamical Mean-Field Approach to Anharmonic Oscillators under Time-Dependent Perturbations Jean-Francois Van Huele, Manuel Berrondo, Jose Recamier We consider the effect of a time-dependent perturbation on an anharmonic oscillator. By expressing the anharmonic oscillator in terms of deformed ladder operators, we obtain the energy spectrum of the unperturbed problem in terms of the quanta of the number operator and an anharmonicity parameter. The combined presence of quadratic terms in the unperturbed Hamiltonian and of the time-dependent perturbation does not lead to a closed algebra and an exact solution. Introducing the mean field in the unperturbed term allows us to obtain a closed algebra with a time-dependent frequency in the unperturbed term. Through factorization of the corresponding evolution operator, the dynamical problem is reduced to a self-consistent system of first-order differential equations. We can now examine this system for transition probabilities, expectation values, phase-space trajectories, and criteria for chaotic behavior in the case of a dipole pulse perturbation. [Preview Abstract] |
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E1.00178: Microscopic Treatment of Lower Dimensional Systems and Weyl Quantization Karla Galdamez A microscopic treatment of nucleation for a three dimensional system was previously presented in which we showed an equivalence between the resulting quantum Hamiltonian and that which is obtained from Weyl quantization, [1]. We now utilize the same procedure on one and two dimensional systems with the goal to again show an identification between Weyl quantization and a microscopic approach to quantization. We hypothesize that there are system characteristics such as density and size that make these similarities possible. Our aim is to attain a greater understanding of the particular traits of systems that lead to an equivalence between Weyl's procedure and that of our microscopic approach. We expect that our results will also be applicable to lower dimensional fluids where the ordering of operators in momentum and position may be at question.\\[4pt] [1] K. Galdamez. Division of Atomic, Molecular and Optical Physics, Microscopic Treatment of Nucleation, 2010, Poster Presentation. [Preview Abstract] |
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E1.00179: Worldline numerics for electromagnetic Casimir energies Jonathan Mackrory, Tanmoy Bhattacharya, Daniel Steck We present our generalization of the worldline method for calculating electromagnetic Casimir energies. Previously, this method has been restricted to calculations for a scalar field. Our work calculates the Casimir energy due to dispersionless, dielectric bodies with arbitrary geometries. The worldline method calculates the energy by first generating an ensemble of closed space-time paths via a Monte-Carlo algorithm, and then summing up the contributions from the dielectric along each path. We are working on extending the method to include the dispersion and dissipation of the dielectric. We will present numerical results, and compare our method with other algorithms and known test cases. [Preview Abstract] |
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E1.00180: Recursive Algorithms Solving Inverse Scattering Problems on Quantum Graphs Nina Avdonina, Sergei Avdonin Here we describe a new approach to solving inverse scattering problems on quantum graphs. Our approach is based on the Boundary Control method and combines spectral, dynamical and scattering approaches to inverse problems. The Schrodinger equations with short--range potentials are considered on the edges of the graph. We use connections between the scattering matrix, Titchmarsh--Weyl matrix and response operator. Since the number of edges of graphs arising in applications is typically very big, we propose a recursive procedure which may serve as a base for developing effective numerical algorithms. For trees (graphs without cycles), this procedure allows recalculating efficiently the inverse data from the original tree to the smaller trees, `removing' leaves step by step up to the rooted edge. We solve the inverse problem of recovering not only the physical properties, i.e. the lengths of the edges and corresponding potentials, but also the topology of the tree. [Preview Abstract] |
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E1.00181: Many-body Contributions to Green's Functions and Casimir Energies Martin Schaden, Kuloth V. Shajesh We use a multiple scattering formalism to extract finite $N$- body parts of Green's functions and Casimir energies that describe the interaction of $N$ objects that do not have a common intersection [arXiv:1011.2475]. For local interactions the $N$-body scattering matrix is expressed in terms of single- body transition matrices. The $N$-body Casimir energy is given by the trace of the $N$-body piece of the corresponding Green's function. This formally requires solution of a set of linear integral equation. The three-body piece of the Casimir energy of a massless scalar field interacting with potentials is derived and we explicitly evaluate it for three parallel semi-transparent plates and for weakly interacting wedges placed on Dirichlet plates. In all these cases the three-body contribution to the vacuum energy is positive. We observe that the three-body Casimir energy for a triangular-wedge enclosing a given area with the Dirichlet plate is minimal when the shorter side of the wedge is perpendicular to the plate. [Preview Abstract] |
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E1.00182: No Gravitational Lensing in Vacuum Space a fraction of a Solar Radius above Solar Rim Edward Dowdye Significant findings show that one of the most misunderstood of all observed astrophysical phenomena is that of gravitational lensing. The Mathematical Physics of Gauss' law of gravity, the analogy of the Gauss' law of charges is directly applicable to the gravitational light bending at the sun. Astrophysical observations are consistent with an indirect interaction involving a plasma medium, not a direct interaction in the empty vacuum space above the rim. A century of observations reveal that gravitational light bending effects have been noted to occur predominantly at the thin plasma rim of the sun, not in the vacuum space a fraction of a solar radius above the rim. Light bending as predicted by General Relativity should be an easily detectable at analytical Gaussian spherical surfaces of various radii; at 2R, 3R, 4R and 5R respectively, where R is the radius of the sun. The observational evidence is clearly inconsistent with the light bending rule of General Relativity since this vacuum space and the solar plasma rim are exposed to virtually the same field. [Preview Abstract] |
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E1.00183: Robust microfabricated surface ion traps with arbitrary lateral geometries D.L. Moehring, T. Barrick, F. Benito, M.G. Blain, M. Descour, A.R. Ellis, K.M. Fortier, R.A. Haltli, C. Highstrete, S.A. Kemme, J. Sterk, D. Stick, B.P. Tabakov, C.P. Tigges We will present the status of Sandia’s efforts to engineer surface ion traps, specifically detailing our ability to reliably fabricate arbitrary surface geometries. These achievements include the precision placement of backside holes for loading from a neutral atom source, multi-level metalization which supports vertical interconnects and low electrical power loss in the substrate, and low profile wirebonds for surface laser access [1, 2]. We have combined these capabilities to produce a successful and robust Y-junction trap which takes advantage of numerical simulations to tailor the RF pseudopotential field in the junction with precisely shaped electrodes [3]. We will also present ongoing work at fabricating structures for quantum simulations in collaborations with NIST and MPQ. In addition we will describe traps with an integrated high finesse optical cavity, junction traps capable of reordering strings of ions with multiple species, and ring shaped traps that we are fabricating for the IARPA sponsored MUSIQC program. [1] D. Stick, et al., arXiv:1008.0990v2 [physics.ins-det] (2010). [2] D. T. C. Allcock, et al., arXiv:1105.4864v1 [quant-ph] (2011). [3] D. L. Moehring, et al., arXiv:1105.1834v1 [quant-ph], accepted for publication (2011). [Preview Abstract] |
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