Emergent Randomness and Benchmarking from Many-Body Quantum Chaos

In this work we find experimental signatures of random quantum state ensembles emerging from evolution with only a global, time-independent Hamiltonian, and use these ensembles to realize a new device benchmarking scheme applicable to both analog and digital quantum simulators. Specifically, we find that measurement results associated with small subsystems exhibit signatures of random state ensembles appearing after chaotic quantum many-body dynamics. This phenomenon turns out to be universal in a wide variety of quantum platforms, enabling the benchmarking of quantum device fidelity with significantly reduced experimental complexity, which we demonstrate using a Rydberg quantum simulator.