Spin symmetry breaking and entropy production during the evolution of spinor Bose-Einstein condensate driven by coherent atom beam

Abstract

The spinor condensate with spin states degenerated in the ground spin-space provides a unique platform for investigating the edge of quantum mechanics and statistical physics. We study the evolution of the condensate under the scattering of a coherent atom beam. The time-dependent magnetization, entanglement entropy, statistical entropy, and the entropy production rate are calculated. A novel spontaneous spin symmetry breaking is found during the evolution. It is shown that the stationary spin distribution can be controlled by the coherent spin state of the incident atom beam, therefore the atom-condensate scattering provides a new way to generate designable spin distributions of the condensate.