Bulletin of the American Physical Society
2014 Annual Meeting of the Far West Section of the APS
Volume 59, Number 14
Friday–Saturday, October 24–25, 2014; Reno, Nevada
Session C2: Atomic, Molecular and Optical Physics |
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Chair: Linda Hirst, University of California at Merced Room: JCSU 423 |
Friday, October 24, 2014 2:00PM - 2:12PM |
C2.00001: Stokes' theorem, gauge symmetry and the time-dependent Aharonov-Bohm effect James Macdougall, Douglas Singleton Stokes' theorem is investigated in the context of the time-dependent Aharonov-Bohm effect -- the two-slit quantum interference experiment with a {\it time varying} solenoid between the slits. The time varying solenoid produces an electric field which leads to an additional phase shift which is found to exactly cancel the time-dependent part of the usual magnetic Aharonov-Bohm phase shift. This electric field arises from a combination of a non-single valued scalar potential and/or a 3-vector potential. The gauge transformation which leads to the scalar and 3-vector potentials for the electric field is non-single valued. This feature is connected with the non-simply connected topology of the Aharonov-Bohm set-up. The non-single valued nature of the gauge transformation function has interesting consequences for the 4-dimensional Stokes' theorem for the time-dependent Aharonov-Bohm effect. An experimental test of these conclusions is proposed. [Preview Abstract] |
Friday, October 24, 2014 2:12PM - 2:24PM |
C2.00002: \textit{Ab initio} electronic structure calculations of spectroscopic constants and vibrational state lifetimes of diatomic alkali molecules Dmitry Fedorov, Andrei Derevianko, Sergey Varganov The diatomic alkali molecules have been proposed as possible candidates for applications in ultracold chemistry, quantum computing, and for high-precision measurements of fundamental constants. We calculate accurate potential energy and permanent dipole moment curves and the lifetimes of the ground and excited vibrational states of the heteronuclear alkali dimers XY (X, Y $=$ Li, Na, K, Rb, Cs) using the coupled cluster with singles doubles and triples (CCSDT) method. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. The dissociation energies are overestimated by only 14 cm$^{-1}$ for LiNa and by no more than 114 cm$^{-1}$ for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 cm$^{-1}$, and the discrepancies for the anharmonic correction are less than 0.1 cm$^{-1}$. The transition dipole moments between all vibrational states, the Einstein coefficients, and the lifetimes of the vibrational states are calculated. We analyze the decay rates of the vibrational states in terms of spontaneous emission, and stimulated emission and absorption induced by black body radiation. [Preview Abstract] |
Friday, October 24, 2014 2:24PM - 2:36PM |
C2.00003: Searching for non-Newtonian gravity with optically levitated microsphere in vacuum Gambhir Ranjit, David Atherton, Jordan Stutz, Mark Cunningham, Andrew Geraci In this talk, I will present our experimental approach [1] towards the search of deviations from Newtonian gravity at short range predicted by several theories beyond the Standard model- including supersymmetry and string theory. In our experiment, we use an optically levitated and cooled dielectric nanosphere in vacuum as a micromechanical sensor which can have extremely high sensitivity of $\sim 10^{-21}N/\sqrt{Hz}$. I will discuss our progress towards cooling of the center-of-mass motion of the trapped bead and the calibration of the sensor using known modulated electric fields.\\[4pt] [1] Andrew A. Geraci, Scott B. Papp, and John Kitching, Phys. Rev. Lett. 102, 101101 (2010) [Preview Abstract] |
Friday, October 24, 2014 2:36PM - 2:48PM |
C2.00004: Laser spectroscopy {\&} optical pumping of matrix-isolated rubidium atoms Andrew Kanagin, Pawan Pathak, Sameer Regmi, Chase Hartzell, Jonathan Weinstein Solid state systems are of particular interest in quantum information science due to their experimental simplicity. Atoms planted in noble gas or similar environments are a promising system to explore, offering high spin densities and potentially long spin coherence times [1-2]. We have implanted rubidium atoms within solid crystals of cryogenic argon and neon [1]. Furthermore, we have grown crystals with thicknesses \textgreater 10 $^{4}$ m and with rubidium densities of 10$^{17}$ cm$^{-3}$ [3]. As such, they are a promising environment for quantum information experiments, as well as sensors such as magnetometers. We will report on measurements of spin lifetimes and discuss our future endeavors. * weinstein@physics.unr.edu \\[4pt] [1] Stuart L. Kupferman and F. M. Pipkin. Phys. Rev., 166, 207--218, 1968.\\[0pt] [2] S. I. Kanorsky, S. Lang, S. L\"{u}cke, S. B. Ross, T. W. H\"{a}nsch, and A. Weis. Phys. Rev. A, 54, R1010--R1013. [Preview Abstract] |
Friday, October 24, 2014 2:48PM - 3:00PM |
C2.00005: Laser spectroscopy of LiHe, a van der Waals molecule Naima Tariq, Nada Al Taisan, Vijay Singh, Jonathan Weinstein Van der Waals molecules are extremely long-range, extremely weakly-bound molecules [1]. Lithium helium (LiHe) is an interesting van der Waals molecule due to theoretical interest in its molecular structure and properties. We report the first observation of ground state LiHe molecules. We use cryogenic helium buffer gas cooling to produce high densities of atomic lithium at temperatures ranging from 1-5 Kelvin [2]. LiHe molecules are formed by three body recombination: Li $+$ He $+$ He $\leftrightarrow $ LiHe $+$ He (1) The Li density is continuously monitored via laser absorption spectroscopy. LiHe is detected spectroscopically using both laser induced fluorescence and laser absorption spectroscopy. The LiHe spectrum shows good agreement with a theoretical model of the molecular structure, with only a single bound rovibrational state. Our data shows good agreement with the model which describes the expected density of product(LiHe) varies with temperature and reactants' densities [3] and we also use it to determine the binding energy of the LiHe ground state. The measured binding energy is consistent with the calculated value [4]. References [1] B.L Balney and G.E.Ewing, Annual Review of Physical Chemistry 27, 553(1976). [2] Naima Tariq, Nada Al Taisan, Vijay Singh, and Jonathan D.Weinstein.Phys. Rev.Lett.,\textbf{110}, 153201, 2013. [3] N.Brahms, T.V. Tscherbul, P. Zhang, J. Klos, H.R. Sadeghpour, A. Dalgarno, J. M. Doyle, and T.G. Walker, Phys Rev. Lett. \textbf{105}, 033001 (2010). [4] U. Kleinekath\"{o}fer, M. Lewerenz, and M. Mladenovi\'{c} ,Phys.Rev. Lett.,83, 4717-4720, 1999. [Preview Abstract] |
Friday, October 24, 2014 3:00PM - 3:12PM |
C2.00006: Micro-mechanical coupling of cold atoms Cris Montoya, Jose Valencia, Andrew Geraci, Matthew Eardley, John Kitching The boundary between quantum microscopic phenomena and macroscopic systems can be studied by coupling a quantum system with well understood coherence properties with a macroscopic system. Micro-mechanical resonators provide single-spin sensitivity and sub-micron spatial resolution; these micro resonators can be used to study decoherence and quantum control when applied to probe ultra-cold atoms. In the future, hybrid quantum systems consisting of cold atoms interfaced with mechanical devices may have applications in quantum information science. We describe our experiment to couple laser-cooled Rubidium atoms to a magnetic cantilever tip. This cantilever is precisely defined on the surface of a chip with lithography and the atoms are trapped at micron-scale distances from this chip. To match cantilever mechanical resonances, atomic magnetic resonances are tuned with a magnetic field. [Preview Abstract] |
Friday, October 24, 2014 3:12PM - 3:24PM |
C2.00007: The Classical Cheshire Cat David Atherton, Gambhir Ranjit, Andrew Geraci, Jonathan Weinstein In this talk we will discuss the phenomenon of the Quantum Cheshire Cat which has recently received significant attention from popular science outlets after the Nature publication of a recent neutron interferometry experiment. The authors of the experiment argue that their results can be interpreted as the spin of the neutron being physically separated from the neutron location. We have reproduced and extended these results with an equivalent optical interferometer. We also could argue that our results suggest that the photon travels through one arm of the interferometer, while its polarization travels through the other. However, we show that these experimental results belong to the domain where quantum and classical wave theories coincide; there is nothing uniquely quantum about the illusion of this Cheshire cat. [Preview Abstract] |
Friday, October 24, 2014 3:24PM - 3:36PM |
C2.00008: Modeling the electron as a circulating charged photon Richard Gauthier A new semi-classical model of the electron shows a number of relativistic and quantum mechanical features of the electron by modeling the electron as a circulating charged photon. A charged photon and its light-speed helical trajectory are a solution to the relativistic electron's energy-momentum equation. This charged photon quantitatively resembles the light-speed electron described by Dirac. The electron's velocity is the longitudinal component of the photon's helically circulating velocity. The electron's relativistic energy is the charged photon's energy. The electron's relativistic momentum is the longitudinal component of the charged photon's helically circulating momentum. At any electron speed, the charged photon has an internally circulating transverse momentum mc, which at the helical radius hbar/2mc for a resting electron (found from analyzing the Dirac equation) produces the z-component of the electron's spin hbar/2. The two helicities of the helical trajectory correspond to a spin-up and a spin-down electron. The two possible charges of the charged photon correspond to the electron and the positron. The circulating charged photon produces one-half of the pre-QED magnetic moment predicted by the Dirac equation for the relativistic electron. [Preview Abstract] |
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