Ultracold atomic gases have been excellent testbeds for studying universal non-equilibrium phenomena such as the Kibble-Zurek mechanism, dynamical critical phenomena, and phase ordering (coarsening) dynamics. Recently, as a universal thermalization scenario, a non-thermal fixed point (NTFP) is becoming an interesting research topic, which is considered to describe universal relaxation dynamics even far from critical points or without them. In fact, two experimental groups have successfully observed signatures of NTFPs in one-dimensional (1D) scalar and spinor Bose gases [1,2]. The physical mechanisms behind the NTFPs in the 1D systems, however, has remained elusive. Against this backdrop, we theoretically study relaxation dynamics in a 1D antiferromagnetic spin-1 Bose gas. Employing the truncated Wigner approximation, we find universal relaxation dynamics consistent with the NTFP scenario. Furthermore, focusing on a magnetic soliton structure, we uncover that it plays a crucial role in emergence of the universal relaxation dynamics. In the seminar, we show these results and discuss experimental possibility to observe the universal behavior.
[1] S. Erne et al., Nature 563, 225 (2018).
[2] M. Prüfer et al., Nature 563, 217 (2018).
Host: Nir Navon