Crossover from weak to strong quench in a spinor Bose-Einstein condensate
Seji Kang, Deokhwa Hong, Joon Hyun Kim +1 more
We investigate the early-time dynamics of a quasi-two-dimensional spin-1 antiferromagnetic Bose-Einstein condensate after a sudden quench from the easy-plane to the easy-axis polar phase. The postquench dynamics shows a crossover behavior as the quench strength $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{q}$ is increased, where $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{q}$ is defined as the ratio of the initial excitation energy per particle to the characteristic spin interaction energy. For a weak quench of $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{q}<1$, long-wavelength spin excitations are dominantly generated, leading to the formation of irregular spin domains. With increasing $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{q}$, the length scale of the initial spin excitations decreases, and we demonstrate that the long-wavelength instability is strongly suppressed for high $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{q}>2$. The observed crossover behavior is found to be consistent with the Bogoliubov description of the dynamic instability of the initial spinor condensate.
arXiv:1909.00681•Physical Review A•Feb 20, 2020•7 citations