1210.5853 (Qi Zhou et al.)

The Fate of Bose-Einstein Condensate in the Presence of Spin-Orbit
Coupling    [PDF]

Qi Zhou, Xiaoling Cui

Intensive theoretical studies have recently predicted that a Bose-Einstein condense exhibits a variety of novel properties if spin-orbit coupling is present. However, an unambiguous fact has also been pointed out that Rashba coupling destroys a condensate of non-interacting bosons even in high dimensions. Therefore, a conceptually important question arises, whether a condensate exists in the presence of interaction and a general type of spin-orbit coupling? Here we show that interaction qualitatively changes the ground state of bosons under Rashba spin-orbit coupling. Any infinitesimal repulsion forces bosons either to condense at one or two momentum states, or to form a Schrodinger-Cat state that is a superposition of infinite numbers of fragmented condensates. The Schrodinger-Cat is unstable against the anisotropy of spin-orbit coupling in systems with large numbers of particles, leading to the revival of a condensate in current experiments.

View original: http://arxiv.org/abs/1210.5853