Integer characteristic polynomial factorization and Hilbert space fragmentation

Fuente: arXiv
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Main Authors: Regnault, Nicolas, Liu, Shuo, Bernevig, B. Andrei
Format: Preprint
Published: 2022
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author Regnault, Nicolas
Liu, Shuo
Bernevig, B. Andrei
author_facet Regnault, Nicolas
Liu, Shuo
Bernevig, B. Andrei
contents Models with Hilbert space fragmentation are characterized by (exponentially) many dynamically disconnected subspaces, not associated with conventional symmetries but captured by nontrivial Krylov subspaces. These subspaces usually exhibit a whole range of thermalization properties, from chaotic to integrable, to quantum many-body scars. However, so far, they have not been properly defined, nor can they be easily found, given a Hamiltonian. In this work, we consider Hamiltonians that have integer representations, a common feature of many (most) celebrated models in condensed matter. We show the equivalence of the integer characteristic polynomial factorization and the existence of Krylov subspaces generated from integer vectors. Considering the pair-hopping model, we illustrate how the factorization property can be used as a method to unveil Hilbert space fragmentation. We discuss the generalization over other rings of integers, for example those based on the cyclotomic field which are relevant when working in a given ($\ne 0, π$) momentum sector.
format Preprint
id arxiv_https___arxiv_org_abs_2210_08019
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Integer characteristic polynomial factorization and Hilbert space fragmentation
Regnault, Nicolas
Liu, Shuo
Bernevig, B. Andrei
Statistical Mechanics
Quantum Physics
Models with Hilbert space fragmentation are characterized by (exponentially) many dynamically disconnected subspaces, not associated with conventional symmetries but captured by nontrivial Krylov subspaces. These subspaces usually exhibit a whole range of thermalization properties, from chaotic to integrable, to quantum many-body scars. However, so far, they have not been properly defined, nor can they be easily found, given a Hamiltonian. In this work, we consider Hamiltonians that have integer representations, a common feature of many (most) celebrated models in condensed matter. We show the equivalence of the integer characteristic polynomial factorization and the existence of Krylov subspaces generated from integer vectors. Considering the pair-hopping model, we illustrate how the factorization property can be used as a method to unveil Hilbert space fragmentation. We discuss the generalization over other rings of integers, for example those based on the cyclotomic field which are relevant when working in a given ($\ne 0, π$) momentum sector.
title Integer characteristic polynomial factorization and Hilbert space fragmentation
topic Statistical Mechanics
Quantum Physics
url https://arxiv.org/abs/2210.08019