Phys. Rev. A 68, 053614 (2003) [8 pages]Quasispin model for macroscopic quantum tunneling between two coupled Bose-Einstein condensatesReceived 22 October 2002; revised 11 June 2003; published 21 November 2003 The system of two coupled Bose-Einstein condensates is mapped onto a uniaxial spin with an applied magnetic field. The mean-field interaction, the coupling, and the asymmetry or the detuning correspond to the anisotropy, the transverse field, and the longitudinal field, respectively. A generalized Bloch equation is derived. In the low barrier limit for the quasispin model, the tunneling rate is analyzed with an imaginary-time path-integral method. The dependence of the tunneling rate on the system parameters is obtained. The crossover temperature Tc from the thermal regime to the quantum regime is estimated. Below Tc quantum tunneling prevails, otherwise thermal activation dominates. © 2003 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevA.68.053614
DOI:
10.1103/PhysRevA.68.053614
PACS:
03.75.Lm, 05.30.Jp, 32.80.Pj, 74.50.+r
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