Polarized and unpolarized phases of spin-orbit-coupled Bose-Einstein condensates in optical lattice

We investigate the phase transition of the Bose-Einstein condensates with equal-weight Rashba and Dresselhaus spin-orbit coupling trapped in one-dimensional optical lattice. Based on the variational and two-mode approximation, the critical condition for phase transition between polarized and unpolarized Bloch wave phase is obtained analytically for the first time, which explicitly reveals rich competitive relationship among spin-orbit coupling, optical lattice and atomic interactions in determining the phase transition of the system. It is shown that the change of the energy minima and the phase transition point by the optical lattice depends on the atomic interactions and spin-orbit coupling. Our results provide a theoretical evidence for deep understanding of the competition mechanism between the optical lattice and spin-orbit coupling for the ground state phase transition of spin-orbit-coupled Bose-Einstein condensates in optical lattice. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study analytically obtained the critical condition for phase transition of Bose-Einstein condensates with equal-weight Rashba and Dresselhaus spin-orbit coupling in a one-dimensional optical lattice, revealing rich competitive relationships. The change in energy minima and phase transition point by the optical lattice was found to depend on atomic interactions and spin-orbit coupling. The theoretical evidence provided a deep understanding of the competition mechanism between optical lattice and spin-orbit coupling for ground state phase transition.