Quantum dynamics in splitting a harmonically trapped Bose-Einstein condensate by an optical lattice: truncated Wigner approximation
Quantum dynamics in splitting a harmonically trapped Bose-Einstein condensate by an optical lattice: truncated Wigner approximation
We study the splitting of a harmonically trapped atomic Bose-Einstein condensate when we continuously turn up an optical lattice, or a double-well, potential. As the lattice height is increased, quantum fluctuations of atoms are enhanced. The resulting nonequilibrium dynamics of the fragmentation process of the condensate, the loss of the phase coherence of atoms along the lattice, and the reduced atom number fluctuations in individual lattice sites are stochastically studied within the truncated Wigner approximation. We perform a detailed study of the effects of temperature and lattice height on atom dynamics, and investigate the validity of the classical Gross-Pitaevskii equation in optical lattices. We find the atom number squeezing to saturate in deep lattices due to nonadiabaticity in turning up of the lattice potential that is challenging to avoid in experiments when the occupation number of the lattice sites is large, making it difficult to produce strongly number squeezed, or the Mott insulator, states with large filling factors. We also investigate some general numerical properties of the truncated Wigner approximation.
bose-einstein condensation, radiation pressure, fluctuations, stochastic processes, lattice theory
063625-[16pp]
Isella, L.
1765053a-638b-49b4-af0c-1b92ce79bf2c
Ruostekoski, J.
2beb155e-64b0-4ee9-9cfe-079947a9c9f4
22 December 2006
Isella, L.
1765053a-638b-49b4-af0c-1b92ce79bf2c
Ruostekoski, J.
2beb155e-64b0-4ee9-9cfe-079947a9c9f4
Isella, L. and Ruostekoski, J.
(2006)
Quantum dynamics in splitting a harmonically trapped Bose-Einstein condensate by an optical lattice: truncated Wigner approximation.
Physical Review A, 74 (6), .
(doi:10.1103/PhysRevA.74.063625).
Abstract
We study the splitting of a harmonically trapped atomic Bose-Einstein condensate when we continuously turn up an optical lattice, or a double-well, potential. As the lattice height is increased, quantum fluctuations of atoms are enhanced. The resulting nonequilibrium dynamics of the fragmentation process of the condensate, the loss of the phase coherence of atoms along the lattice, and the reduced atom number fluctuations in individual lattice sites are stochastically studied within the truncated Wigner approximation. We perform a detailed study of the effects of temperature and lattice height on atom dynamics, and investigate the validity of the classical Gross-Pitaevskii equation in optical lattices. We find the atom number squeezing to saturate in deep lattices due to nonadiabaticity in turning up of the lattice potential that is challenging to avoid in experiments when the occupation number of the lattice sites is large, making it difficult to produce strongly number squeezed, or the Mott insulator, states with large filling factors. We also investigate some general numerical properties of the truncated Wigner approximation.
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Published date: 22 December 2006
Additional Information:
6362
Keywords:
bose-einstein condensation, radiation pressure, fluctuations, stochastic processes, lattice theory
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Local EPrints ID: 45720
URI: http://eprints.soton.ac.uk/id/eprint/45720
ISSN: 1050-2947
PURE UUID: f4331642-8961-4714-9637-8767202ac448
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Date deposited: 02 Apr 2007
Last modified: 15 Mar 2024 09:12
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Author:
L. Isella
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