Non-ergodic one-magnon magnetization dynamics of the kagome lattice antiferromagnet

TL;DR

This paper explores non-ergodic one-magnon dynamics in the kagome lattice antiferromagnet, highlighting how flat bands induce localization and prevent thermalization, challenging typical expectations of equilibrium in quantum systems.

Contribution

It demonstrates that flat bands in the kagome lattice cause disorder-free localization, leading to non-equilibrating one-magnon dynamics, an example of non-ergodic behavior.

Findings

Flat bands induce localization in kagome lattice antiferromagnet.

Localized magnons prevent system from thermalizing.

Non-ergodic dynamics due to flat band effects.

Abstract

The present view of modern physics on non-equilibrium dynamics is that generic systems equilibrate or thermalize under rather general conditions, even closed systems under unitary time evolution. The investigation of exceptions thus not only appears attractive, in view of quantum computing where thermalization is a threat it also seems to be necessary. Here, we present aspects of the one-magnon dynamics on the kagome lattice antiferromagnet as an example of a non-equilibrating dynamics due to flat bands. Similar to the one-dimensional delta chain localized eigenstates also called localized magnons lead to disorder-free localization and prevent the system from equilibration.