Quantum information spreading in random spin chains

TL;DR

This paper investigates how quantum correlations and information spread in a disordered one-dimensional spin chain after a quantum quench, using analytical and numerical methods to understand the dynamics of entanglement and mutual information.

Contribution

It provides analytical predictions for the scaling behavior of quantum information spreading in disordered spin chains and supports these with numerical simulations in the non-interacting limit.

Findings

Quantum correlations spread logarithmically with time.

Analytical scaling predictions match numerical results.

Disorder induces unique entanglement dynamics in the spin chain.

Abstract

We study the spreading of quantum correlations and information in a one-dimensional quantum spin chain with critical disorder as encoded in an infinite randomness fixed point. Specifically, we focus on the dynamics after a quantum quench of the R\'enyi entropies, of the mutual information and of the entanglement negativity in the prototypical XXZ spin chain with random bonds and anisotropy parameters. We provide analytic predictions in the scaling regime based on real-space renormalization group methods. We support these findings through numerical simulations in the non-interacting limit, where we can access the scaling regime.