Synthetic Lorentz force in classical atomic gases via Doppler effect and radiation pressure

Seminar

Speaker: Hrvoje Buljan
When: Mar. 25 2014 09:15
Where: Erwin Schrödinger Saal

The quest for synthetic magnetism in quantum degenerate atomic gases is motivated by the research of controllable quantum emulators, which could mimic complex quantum systems. Recent experiments in Bose-Einstein condensates have produced synthetic magnetic fields by spatially dependent optical coupling of the internal atomic states [1, 2]. The mechanism is based upon the analogy between the Aharonov-Bohm phase of charged quantum particles and the Berry phase of atoms adiabatically traversing closed loops in specially tailored laser fields [3]. However, classical (rather than quantum degenerate) cold atomic gases have been circumvented in the quest for synthetic magnetism, even though they could emulate in a controllable fashion, and in table-top experiments, versatile complex classical systems. One such desirable system for table-top emulation is tokamak plasma. Because of the fairly large atomic velocities, methods based on their adiabatic motion are limited and the desired synthetic magnetic fields should cover larger areas (typically of square millimeter size). On the other hand, schemes for classical gases do not need to be limited by avoiding spontaneous emission. With these guidelines, we present a scheme for obtaining synthetic magnetic fields in classical gase, which is based on the Doppler effect and radiation pressure to produce a force perpendicular to the velocity of the atoms. The experimental realization of the scheme is approached with 87Rb atoms cooled in a Magneto-Optical Trap (MOT). Theoretical and experimental results will be presented. The signature of the Lorentz force can be observed in motion of the center of mass (CM) and/or the shape of the atomic cloud. [1] Y-J. Lin, R.L. Compton, K. Jimenez-Garcia, J.V. Porto, I.B. Spielman, Synthetic magnetic fields for ultracold neutral atoms, Nature 462, 628 (2009). [2] L.J. Le Blanc, K. Jimenez-Garcia, R.A. Williams, M.C. Beeler, A.R. Perry, W.D. Phillips, and I.B. Spielman, Observation of a superuid Hall effect, PNAS 109, 10811 (2012). [3] R. Dum and M. Olshanii, Gauge Structures in Atom-Laser Interaction: Bloch Oscillations in a Dark Lattice, Phys. Rev. Lett. 76, 1788 (1996). [4] T. Dubček, N. Šantić, D. Jukić, D. Aumiler, T. Ban, and H. Buljan, Synthetic Lorentz force in classical atomic gases via Doppler effect and radiation pressure, arXiv:1402.7251

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