Ergodicity Breaking Under Confinement in Cold-Atom Quantum Simulators

The quantum simulation of gauge theories on synthetic quantum matter devices has gained a lot of traction in the last decade, making possible the observation of a range of exotic quantum manybody phenomena. In this work, we consider the spin -1/2 quantum link formulation of 1 + 1D quantum electrodynamics with a topological theta-angle, which can be used to tune a confinement-deconfinement transition. Exactly mapping this system onto a PXP model with mass and staggered magnetization terms, we show an intriguing interplay between confinement and the ergodicity-breaking paradigms of quantum many -body scarring and Hilbertspace fragmentation. We map out the rich dynamical phase diagram of this model, finding an ergodic phase at small values of the mass mu and confining potential x, an emergent integrable phase for large mu, and a fragmented phase for large values of both parameters. We also show that the latter hosts resonances that lead to a vast array of effective models. We propose experimental probes of our findings, which can be directly accessed in current cold -atom setups.