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Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Quantum dynamics in splitting a harmonically trapped Bose-Einstein condensate by an optical lattice
T2 - truncated Wigner approximation
AU - Isella, L.
AU - Ruostekoski, J.
N1 - 6362
PY - 2006/12/22
Y1 - 2006/12/22
N2 - 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.
AB - 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.
KW - bose-einstein condensation
KW - radiation pressure
KW - fluctuations
KW - stochastic processes
KW - lattice theory
U2 - 10.1103/PhysRevA.74.063625
DO - 10.1103/PhysRevA.74.063625
M3 - Journal article
VL - 74
JO - Physical review a
JF - Physical review a
SN - 1050-2947
IS - 6
M1 - 063625
ER -