Permanent oscillations and solitary wave behavior in flatband Heisenberg quantum spin systems

TL;DR

This paper demonstrates that flatband Heisenberg quantum spin systems can exhibit persistent oscillations in the form of solitary waves, challenging typical expectations of thermalization in closed quantum systems.

Contribution

It introduces the phenomenon of perpetual solitary wave oscillations in flatband quantum spin systems, expanding understanding of non-ergodic behavior beyond time-crystalline phases.

Findings

Persistent solitary waves observed in flatband Heisenberg spin systems

Phenomenon is robust across various dimensions and frustrated systems

Applicable to Hubbard models and other quantum many-body systems

Abstract

Research on the emergence of thermodynamics in closed quantum systems under unitary time evolution arrived at the consensus that generic systems equilibrate under rather general assumptions. A new focus of the field is thus on exceptions. Persistent oscillations are one possible hallmark of non-ergodic time evolution. While time-crystalline behavior results from, e.g., many-body localization, here we show that ever-revolving solitary waves emerge in flatband Heisenberg quantum spin systems. This phenomenon is rather general for a variety of frustrated spin systems in one, two, and three dimensions as well as for Hubbard systems.