# Eigenstate thermalization hypothesis in quantum dimer models

## TL;DR

This study investigates the eigenstate thermalization hypothesis in quantum dimer models, revealing that ETH holds within topological sectors but breaks down when sectors are combined, highlighting complex thermalization behavior.

## Contribution

The paper demonstrates that ETH validity in quantum dimer models depends on topological sector separation and specific Hamiltonian parameters, providing new insights into thermalization in constrained quantum systems.

## Key findings

- ETH is satisfied within individual topological sectors.
- ETH breaks down when the spectrum is considered as a whole.
- Thermalization dynamics are influenced by topological constraints.

## Abstract

We use exact diagonalization to study the eigenstate thermalization hypothesis (ETH) in the quantum dimer model on the square and triangular lattices. Due to the nonergodicity of the local plaquette-flip dynamics, the Hilbert space, which consists of highly constrained close-packed dimer configurations, splits into sectors characterized by topological invariants. We show that this has important consequences for ETH: We find that ETH is clearly satisfied only when each topological sector is treated separately, and only for moderate ratios of the potential and kinetic terms in the Hamiltonian. By contrast, when the spectrum is treated as a whole, ETH breaks down on the square lattice, and apparently also on the triangular lattice. These results demonstrate that quantum dimer models have interesting thermalization dynamics.