Subexponential decay of local correlations from diffusion-limited dephasing

Date

Aug 11, 2025

Time

4:30 PM - 5:30 PM

Speaker

Dr. Curt von Keyserlingk

Affiliation

King's College London

Series

MPI-PKS Kolloquium

Language

en

Main Topic

Physik

Other Topics

Physik

Description

Chaotic quantum systems at finite energy density are expected to act as their own heat baths, rapidly dephasing local quantum superpositions. We argue that in fact this dephasing is subexponential for chaotic dynamics with conservation laws in one spatial dimension: all local correlation functions decay as stretched exponentials or slower. The stretched exponential bound is saturated for operators that are orthogonal to all hydrodynamic modes. This anomalous decay is a quantum coherent effect, which lies beyond standard fluctuating hydrodynamics; it vanishes in the presence of extrinsic dephasing. Our arguments are general, subject principally to the assumption that there exist zero-entropy charge sectors (such as the particle vacuum) with no nontrivial dynamics: slow relaxation is due to the persistence of regions resembling these inert vacua, which we term "voids". In systems with energy conservation, this assumption is automatically satisfied because of the third law of thermodynamics.

Last modified: Aug 11, 2025, 7:35:46 AM