Entanglement-enhanced spreading of correlations

TL;DR

This paper investigates how initial entanglement influences the speed and extent of correlation spreading in quantum lattice models, providing bounds and applications in various quantum phenomena.

Contribution

It introduces Lieb-Robinson-type bounds that quantify the impact of initial entanglement on correlation dynamics in nonrelativistic quantum systems.

Findings

Entanglement accelerates correlation growth.

Bounds match model calculations.

Applications to quantum quenches and Kondo physics.

Abstract

Starting from a product initial state, equal-time correlations in nonrelativistic quantum lattice models propagate within a lightcone-like causal region. The presence of entanglement in the initial state can modify this behavior, enhancing and accelerating the growth of correlations. In this paper we give a quantitative description, in the form of Lieb-Robinson-type bounds on equal-time correlation functions, of the interplay of dynamics vs. initial entanglement in quantum lattice models out of equilibrium. We test the bounds against model calculations, and also discuss applications to quantum quenches, quantum channels, and Kondo physics.