DocumentCode :
3351124
Title :
Gauge potentials and tunneling dynamics in optical lattices
Author :
Dutta, S.K. ; Teo, B. ; Raithel, Georg
Author_Institution :
Dept. of Phys., Michigan Univ., Ann Arbor, MI, USA
fYear :
1992
fDate :
23-28 May 1992
Firstpage :
241
Lastpage :
242
Abstract :
Summary form only given. It has been predicted that topological potentials play a significant role in gray optical lattices. However, so far there has been no direct experimental demonstration of their existence. Unlike light-shift potentials, which, in the case of low saturation, scale as the laser intensity, topological (or gauge) potentials are intensity independent and solely depend on the topology of the lattice, which is determined by the detuning, beam geometry and magnetic fields. In our experiment, /sup 87/Rb atoms are collected in a standard magneto-optic trap and loaded into a 1D optical lattice. The lattice is formed by counterpropagating, orthogonally polarized laser beams. The minima of the trapping potential form at the antinodes of the standing waves and, as a result of optical pumping, the wells are alternately occupied. When an atom tunnels from one type of well to another, it must then flip its magnetic spin state. The gauge potential is associated with the energy needed for this change. In this gray lattice, the potential wells are shallow due to the weak interaction with the light field. Shallow potentials are necessary for tunneling. We use two schemes to observe tunneling. In the first, we use an auxiliary weak laser pulse to selectively depopulate one of the two types of wells. We observe tunneling by measuring the population in each type of well as a function of time. The second way we study tunneling is to create atomic wave-packets within the wells and to observe their motion as they oscillate. The wave-packets are created by diabatically displacing the trapped atoms in either position or momentum space. Tunneling occurs when the wave-packets run against barriers provided by the maxima of the trapping potential.
Keywords :
laser cooling; optical pumping; radiation pressure; rubidium; tunnelling; /sup 87/Rb atoms; 1D optical lattice; Rb; atomic wave-packets; auxiliary weak laser pulse; coherent redistribution of photons; gauge potential; gray optical lattices; internal-state wave-function; magneto-optic trap; optical pumping; orthogonally polarized laser beams; potential wells; quantum Monte-Carlo wavefunction simulations; quantum-coherence; selective depopulation; topological potentials; tunneling dynamics; weak interaction; Atom optics; Atomic beams; Atomic measurements; Charge carrier processes; Geometrical optics; Laser beams; Lattices; Magnetic fields; Topology; Tunneling;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Quantum Electronics and Laser Science Conference, 1999. QELS '99. Technical Digest. Summaries of Papers Presented at the
Conference_Location :
Baltimore, MD, USA
Print_ISBN :
1-55752-576-X
Type :
conf
DOI :
10.1109/QELS.1999.807608
Filename :
807608
Link To Document :
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