Universal roughness scaling in strongly interacting quantum gases far from equilibrium

Understanding how universal dynamics emerge in complex many-body systems is a central goal of modern physics. In classical systems, universality of nonequilibrium dynamics is exemplified by dynamic scaling of surface growth processes, formulated by the Family-Vicsek (FV) scaling that connects temporal and spatial fluctuations through dynamic exponents. Recent theoretical work suggests that FV scaling also governs nonequilibrium dynamics in quantum many-body systems, yet experimental confirmation remains lacking. In this talk, I will introduce our recent experimental work that demonstrates FV scaling in one-dimensional strongly interacting quantum gases in optical lattices. Using a quantum gas microscope, we reconstruct the quantum height by measuring the site occupation number and study the roughness dynamics of the quantum height with various system sizes. The roughness curve follows a universal curve upon rescaling the system size and hold time, confirming the FV scaling. Furthermore, the quantum system continues to exhibit FV scaling even under time-dependent perturbations, where the universality class has been changed from ballistic to the Edwards-Wilkinson diffusive class. Our results demonstrate the robustness of the full FV scaling in a strongly interacting quantum many-body system, offering new pathways to connect nonequilibrium quantum dynamics with classical fluctuating hydrodynamics.