Exploring Dynamical Phases in a Multilevel Atom-Cavity System*

Out-of-equilibrium dynamics of many-body systems can exhibit rich behavior not found in equilibrium systems. For example, certain non-dissipative, interacting systems can experience distinct dynamical phases when externally driven or quenched out of equilibrium. These “dynamical phases” have associated phase transitions which become sharp in the thermodynamic limit. Cavity-mediated interactions between cold atoms trapped in an optical cavity can act as a powerful tool to study such systems. Previously, we observed a dynamical phase transition using an ensemble of ~10^{6 88}Sr atoms coupled to a cavity along the narrow-linewidth ¹S₀-³P₁ transition [1]. We have also proposed a scheme to simulate dynamics of a low-energy BCS superconductor, which exhibits three dynamical phases [2]. In this talk, we present progress towards observing dynamical phases in a multilevel system composed of the ¹S₀ ground state and the m = ±1 Zeeman states of the ³P₁ manifold in ⁸⁸Sr. By varying the Zeeman splitting between the excited states and introducing controlled inhomogeneity in the atomic transition frequency across the ensemble, we expect to map out a full phase diagram and measure the distinct dynamics in different phases of the system.

[1] Nature 580, 602-607 (2020)

[2] PRL 126, 173601 (2021)