Benchmarking quantum computers in nonequilibrium quantum simulations

The problems on which quantum computers will demonstrably outperform classical computers remains surprisingly unclear. Quantum simulation is one area where an exponential advantage is expected, yet establishing this advantage is not straightforward. Here, we propose a scheme for verifying quantum simulations of nonequilibrium dynamics at scale, based on a special class of quantum many-body scars known as stabilizer scars. Our approach leverages the structure of these states to guarantee efficient fidelity estimation, and our analysis connects the fidelity of classically simulable scar-subspace states to that of typical, non-simulable states.