Landau-Forbidden Quantum Criticality in Rydberg Atom Arrays

A continuous transition between two distinct symmetry broken phases is generally forbidden to occur within the celebrated Landau-Ginzburg-Wilson theory of phase transitions. However, a quantum effect can intertwine the two symmetries, giving rise to a novel scenario called deconfined quantum criticality. In this work, we propose a model of a one-dimensional array of strongly-interacting, individually trapped neutral atoms interacting via Rydberg states, and demonstrate through extensive numerical simulations that its ground state phase diagram exhibits deconfined quantum criticality in certain parameter regimes. Moreover, we show how an enlarged, emergent continuous symmetry arises at these critical points, which can be directly observed via studying the joint distribution of two competing order parameters in the natural measurement basis. Our findings highlight quantum simulators of Rydberg atoms not only as natural platforms to experimentally realize such exotic phenomena, but also as unique ones as they allow access to physical properties not accessible in traditional condensed matter experiments.