Universal distributions and noise falsification from bitstring measurements*

Understanding the behavior of quantum systems interacting with their environment is a long-standing problem of interest, but only recently have experiments attained a level of control required to study it microscopically. Here we use a Rydberg atom array to study this process for both coherent and incoherent couplings to the environment. For the coherent case, we observe a smooth transition in the statistics of measurement probabilities from anti-concentrated to concentrated behavior as a function of the environment dimension. Remarkably, we numerically find this observation is universal amongst a wide range of systems, including those at finite temperature, those with itinerant particles, and random circuits. We then generalize this observation to the incoherent case, developing a simple but comprehensive framework for predicting the statistics of measurement probabilities under largely arbitrary noise channels. We demonstrate that this allows for clear discrimination between candidate error models both with numerical simulations of digital quantum circuits and experimentally with our analog quantum simulator.