Quantum many-body scars of spinless fermions with density-assisted hopping in higher dimensions

TL;DR

This paper introduces a new class of spinless fermion models with density-assisted hopping in higher dimensions, revealing quantum many-body scars responsible for nonthermal behavior and nonergodic dynamics.

Contribution

It constructs exact eigenstates and parent Hamiltonians for QMBS in higher-dimensional fermion models with density-assisted hopping.

Findings

Existence of exact QMBS in higher dimensions

Nonthermal dynamics confirmed by entanglement and correlations

Unique ground states as parent Hamiltonians for QMBS

Abstract

We introduce a class of spinless fermion models that exhibit quantum many-body scars (QMBS) originating from kinetic constraints in the form of density-assisted hopping. The models can be defined on any lattice in any dimension and allow for spatially varying interactions. We construct a tower of exact eigenstates with finite energy density, and we demonstrate that these QMBS are responsible for the nonthermal nature of the system by studying the entanglement entropy and correlation functions. The quench dynamics from certain initial states is also investigated, and it is confirmed that the QMBS induce nonthermalizing dynamics. As another characterization of the QMBS, we give a parent Hamiltonian for which the QMBS are unique ground states. We also prove the uniqueness rigorously.