PCS Institute for Basic Science
Title: Observation of universal coarsening dynamics of a quenched ferromagnetic Bose-Einstein condensate
Abstract:
Understanding and classifying out-of-equilibrium dynamics in a closed quantum many-body system have been outstanding problems in modern physics. Ultracold atomic gases provide a pristine platform for studying the nonequilibrium quantum dynamics, where various aspects of thermalization processes have been reported. In this talk, we will introduce our experimental platform of strongly ferromagnetic spin-1 condensate [1] and recent experimental results on the universal coarsening dynamics after a quantum quench. Initially prepared polar condensate is quenched to easy-axis ferromagnetic phase by microwave dressing [2]. Right after the quench, we observe the emission of spin 1/-1 pairs due to dynamical instability [2]. After a long time, they form micro domains, which are coarse to form a larger domain as time evolves. We analyze spin correlation functions at various evolution times, which collapsed onto a single function after rescaling the domain length. The results are compared with numerical simulations, where the dynamics belong to the binary fluid universality class with its dynamical critical exponent z=3/2 [3].
[1] S.-J. Huh, K. Kim, K. Kwon, and J.-y. Choi, Phys. Rev. Research 2, 033471 (2020).
[2] K. Kim, J. Hur, S.-J. Huh, S. Choi, and J.-y. Choi, Phys. Rev. Lett 127, 043401 (2021).
[3] L. A. Williamson and P. B. Blakie, Phys. Rev. Lett. 116, 025301 (2016).
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