Quantum Matter Seminar

In this talk, I will discuss universal fluctuations in natural quantum many-body states produced by generic Hamiltonian dynamics. These fluctuations are present in the outcome statistics of global bitstring measurements and have been used in random circuit sampling tasks for recent quantum advantage claims. Specifically, we demonstrate that the Porter-Thomas distribution, previously known to be present in the measurement outcome probabilities of the output of random quantum circuits, is also present in the output of ergodic quantum dynamics.

Using such fluctuations, I will introduce a sample-efficient protocol which estimates the fidelity between an experimentally prepared state and an ideal target state, and is applicable to a wide class of analog quantum simulators. We further develop this protocol to estimate the mixed state entanglement of the experimentally prepared state. Finally, we demonstrate fidelity benchmarking and mixed-state entanglement estimation in a 60-atom analog Rydberg quantum simulator, and we find that our experiment is competitive with state-of-the-art digital quantum devices performing random circuit evolution.

Based on work with Soonwon Choi, Adam Shaw, Joonhee Choi, Manuel Endres, Pascal Scholl, Ran Finkelstein and Andreas Elben. Phys. Rev. Lett. 131, 110601 (https://doi.org/10.1103/PhysRevLett.131.110601) and arXiv:2308.07914 (https://arxiv.org/abs/2308.07914)