Matrix product symmetries and breakdown of thermalization from hard rod deformations

TL;DR

This paper introduces a method called hard rod deformation to create spin-1/2 chains with matrix product symmetries, leading to Hilbert space fragmentation and thermalization breakdown, observed in both integrable and non-integrable models.

Contribution

It demonstrates that matrix product symmetries can cause thermalization failure in non-integrable systems, expanding understanding of symmetry effects in quantum many-body dynamics.

Findings

Models exhibit persistent oscillations in non-equilibrium states.

Symmetries generate Hilbert space fragmentation.

Breakdown of thermalization observed in non-integrable cases.

Abstract

We construct families of exotic spin-1/2 chains using a procedure called ``hard rod deformation''. We treat both integrable and non-integrable examples. The models possess a large non-commutative symmetry algebra, which is generated by matrix product operators with fixed small bond dimension. The symmetries lead to Hilbert space fragmentation and to the breakdown of thermalization. As an effect, the models support persistent oscillations in non-equilibrium situations. Similar symmetries have been reported earlier in integrable models, but here we show that they also occur in non-integrable cases.