Quasilocalized dynamics from confinement of quantum excitations

TL;DR

This paper reveals how confinement of quantum excitations causes quasilocalized dynamics in one-dimensional quantum systems, suppressing correlation spreading and entanglement growth, with implications for understanding non-equilibrium phenomena.

Contribution

It provides a unified framework linking confinement to slow dynamics and entanglement behavior, supported by effective Hamiltonians and applications to lattice gauge theories and quantum Ising chains.

Findings

Confinement leads to long-lived inhomogeneities and oscillations.

Effective Hamiltonians exhibit Stark localization.

Confinement hinders thermalization in translation-invariant systems.

Abstract

Confinement of excitations induces quasilocalized dynamics in disorder-free isolated quantum many-body systems in one spatial dimension. This occurrence is signalled by severe suppression of quantum correlation spreading and of entanglement growth, long-time persistence of spatial inhomogeneities, and long-lived coherent oscillations of local observables. In this work, we present a unified understanding of these dramatic effects. The slow dynamical behavior is shown to be related to the Schwinger effect in quantum electrodynamics. We demonstrate that it is quantitatively captured for long time scales by effective Hamiltonians exhibiting Stark localization of excitations and weak growth of the entanglement entropy for arbitrary coupling strength. This analysis explains the phenomenology of real-time string dynamics investigated in a number of lattice gauge theories, as well as the anomalous dynamics observed in quantum Ising chains after quenches. Our findings establish confinement as a robust mechanism for hindering the approach to equilibrium in translationally-invariant quantum statistical systems with local interactions.