Quantum Many-Body Scars and Weak Ergodicity Breaking in Rydberg-Atom Quantum Simulators

A perennial mystery of nature is how order can exist amidst chaos. Familiar systems such as the clock pendulum exhibit regular periodic motion. This ordered behaviour, however, is fragile. For example, interactions between particles rapidly lead to chaos, forcing the system to thermalise and "forget" its initial state. This can be visualised as an ice cream that melts away and never finds its way back to the frozen state. "Quantum scars" refer to the surprising behaviour that defies such common intuition: for special initial states, the ice cream periodically melts away and then freezes up again. Recent experiments on ultracold Rydberg atoms have found evidence of similar behaviour where the atoms were able to return to their initial state many times during the measurement. Our recent work [Nature Physics 14, 745 (2018)] has proposed the first theoretical explanation for this phenomenon and named it "quantum many- body scars". At this point, the origins of quantum many-body scars largely remain a mystery. Your project will develop a computer simulation of quantum many-body scars in two-dimensional lattices of Rydberg atoms, with the goal of predicting future experiments on these systems that may unlock a range of applications in the emerging quantum technologies.