Decoherence in Condensates with Chaotic Dynamics in Internal Degrees of Freedom

The stability of systems with underlying internal dynamics is critical to many applications of quantum sciences, such as quantum simulation and metrology. In previous and ongoing works we find that Bose-Einstein condensates (BECs) often exhibit resonant spatial excitations during dynamics within internal degrees of freedom; these resonances can persist even when the energy scales of the internal dynamics are much smaller than those of the spatial excitations. By breaking integrability these spatial excitations induce chaos, potentially allowing for decoherence and thermalization within the closed quantum systems. We develop and apply a generalized few-state framework to various systems such as spinor BECs, BECs with synthetic spin-orbit coupling within optical lattices, and driven quantum gases. We highlight the shared physics between the different systems and introduce a minimalistic model to guide intuition.