Halide perovskite artificial solids as a new platform to simulate collective phenomena in doped Mott insulators

The development of Quantum Simulators, artificial platforms where the predictions of many-body theories of correlated quantum materials can be tested in a controllable and tunable way, is one of the main challenges of condensed matter physics. We introduce artificial lattices made of lead halide perovskite nanocubes as a new platform to simulate and investigate the physics of correlated quantum materials. The ultrafast optical injection of quantum-confined excitons plays a similar role to doping in real materials. We show that, at large photo-doping, the exciton gas undergoes an excitonic Mott transition, which can be mapped on the insulator-to-metal transition of the Hubbard model in a magnetic field. At lower photo-doping, the long-range interactions drive the formation of a collective superradiant state, in which the phases of the excitons generated in each single perovskite nanocube are coherently locked. Our results demonstrate that time-resolved experiments span a parameter region of the Hubbard model in which long-range and phase-coherent orders emerge out of a doped Mott insulating phase. This physics is relevant for a broad class of phenomena, such as superconductivity and charge-density waves in correlated materials whose properties are captured by doped Hubbard models.