Data and Numerical Code for "Free Probability in a Minimal Quantum Circuit Model"

This repository contains data and code for "Free Probability in a Minimal Quantum Circuit Model",Felix Fritzsch and Pieter W. Claeys, arXiv:2506.11197 (2025)DOI: https://doi.org/10.48550/arXiv.2506.11197 ... as it is to appear in the published paper at PRX. Abstract: Recent experimental and theoretical developments in many-body quantum systems motivate the study of their out-of-equilibrium properties through multi-time correlation functions. We consider the dynamics of higher-order out-of-time-order correlators (OTOCs) in a minimal circuit model for quantum dynamics. This model mimics the dynamics of a structured subsystem locally coupled to a maximally random environment. We prove the exponential decay of all higher-order OTOCs and fully characterize the relevant time scales, showing how local operators approach free independence at late times. We show that the effects of the environment on the local subsystem can be captured in a higher-order influence matrix, which allows for a Markovian description of the dynamics provided an auxiliary degree of freedom is introduced. This degree of freedom directly yields a dynamical picture for the OTOCs in terms of free cumulants from free probability, consistent with recent predictions from the full eigenstate thermalization hypothesis (ETH). This approach and the relevant influence matrix are expected to be applicable in more general settings and present a first step to characterizing quantum memory in higher-order OTOCs. FreeProbabilityQuantumCircuits.zip contains: readme.txt the information below Figures: 8 Figures as appeared in the preprint/published version Data: Data sets used for the creation of the figures, stored as .npz archive, for documentation see https://numpy.org/doc/2.2/reference/generated/numpy.savez.html Notebooks: Jupyter notebooks for: 1) Loading and plotting the above data to create the figures used in the preprint 2) Computing higher order OTOCs using the Markovian process presented in the preprint (incl. fixed bug from previous version)