Abstract: 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 T-c from the thermal regime to the quantum regime is estimated. Below T-c quantum tunneling prevails, otherwise thermal activation dominates.

Keywords: ferromagnetic particles; escape rate; interference; states; system; oscillations; magnetization; transitions; dynamics; domains

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