Group Seminar at MPQ and via Zoom: Classifying coarsening dynamics in a quenched ferromagnetic condensate far from equilibrium
Jae-yoon Choi, Korea Advanced Institute of Science & Technology (KAIST)
Group Seminar at MPQ in the Herbert-Walther-Lecture Hall and via zoom
Tuesday, September 20, 9.00 am (MEZ)
Understanding and classifying out-of-equilibrium dynamics in a closed quantum many-body system have been outstanding problems in modern physics. In this talk, we will introduce our experimental platform of strongly ferromagnetic spin-1 condensate  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 . Right after the quench, we observe the emission of spin 1/-1 pairs due to dynamical instability . 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 . As a concluding remakrs, we will also introduce the recent experimetnal apparatus of quantum gas microscope of 7Li atom in two dimensional square lattice  and ongoing research projects.
 S.-J. Huh, K. Kim, K. Kwon, and J.-y. Choi, Phys. Rev. Research 2, 033471 (2020).
 K. Kim, J. Hur, S.-J. Huh, S. Choi, and J.-y. Choi, Phys. Rev. Lett 127, 043401 (2021).
 L. A. Williamson and P. B. Blakie, Phys. Rev. Lett. 116, 025301 (2016).
 K. Kwon , K. Kim , J. Hur , S.-J Huh , and J.-y Choi, Phys. Rev. A 105, 033323(2022).