Kibble-Zurek scaling in a homogeneous unitary Fermi gas

The classification of nonequilibrium physics into a universal framework, regardless of the microscopic constituents of the excitations, has served as a benchmark for understanding its sophisticated dynamics. The Kibble-Zurek (KZ) mechanism, which underlies the formation of topological defects after a system's control parameter is quenched through a continuous phase transition, predicts a power-law dependence of the average number of defects on the quench duration. Here, we report our experiment of a linear temperature quench on a spatially homogeneous unitary Fermi gas across a thermal-to-superfluid transition. The spatially homogeneous trap allows us to analyze the defect formation and order parameter coarsening dynamics without having to rely on the local density approximation. Over a wide range of quench duration, we observe a KZ scaling behavior and show a close agreement with theoretical values depicted in the 3D XY model. For sufficiently fast quench rates, we suggest that the condensate growth dynamics after the end of the quench plays a pivotal role on the generation of topological defects.