Quantum Spin Nematic States in Bose-Einstein Condensates
Abstract
We review some recent results on discrete symmetries and topological order in spinor Bose-Einstein condensates (BECs) of ^{23}Na. For spin one bosons with two-body scatterings dominated by a total spin equal to two channel, the BECs are in quantum spin nematic states at a low density limit. We study spin correlations in condensates at different limits and analyze hidde symmetries using a non-perturbative approach developed recently. We further more investigate the influence of hidden Z_2$ symmetries and U(1) quantum orders in symmetry partially retored states, particularly the effects on topological excitations.