Classification of locality preserving symmetries on spin chains

Fuente: arXiv
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Autores principales: Bols, Alex, De Roeck, Wojciech, De Wilde, Michiel, Carvalho, Bruno de O.
Formato: Preprint
Publicado: 2025
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author Bols, Alex
De Roeck, Wojciech
De Wilde, Michiel
Carvalho, Bruno de O.
author_facet Bols, Alex
De Roeck, Wojciech
De Wilde, Michiel
Carvalho, Bruno de O.
contents We consider the action of a finite group $G$ by locality preserving automorphisms (quantum cellular automata) on quantum spin chains. We refer to such group actions as ``symmetries''. The natural notion of equivalence for such symmetries is \emph{stable equivalence}, which allows for stacking with factorized group actions. Stacking also endows the set of equivalence classes with a group structure. We prove that the anomaly of such symmetries provides an isomorphism between the group of stable equivalence classes of symmetries with the cohomology group $H^3(G,U(1))$, consistent with previous conjectures. This amounts to a complete classification of locality preserving symmetries on spin chains. We further show that a locality preserving symmetry is stably equivalent to one that can be presented by finite depth quantum circuits with covariant gates if and only if the slant product of its anomaly is trivial in $H^2(G, U(1)[G])$.
format Preprint
id arxiv_https___arxiv_org_abs_2503_15088
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Classification of locality preserving symmetries on spin chains
Bols, Alex
De Roeck, Wojciech
De Wilde, Michiel
Carvalho, Bruno de O.
Quantum Physics
Strongly Correlated Electrons
Mathematical Physics
We consider the action of a finite group $G$ by locality preserving automorphisms (quantum cellular automata) on quantum spin chains. We refer to such group actions as ``symmetries''. The natural notion of equivalence for such symmetries is \emph{stable equivalence}, which allows for stacking with factorized group actions. Stacking also endows the set of equivalence classes with a group structure. We prove that the anomaly of such symmetries provides an isomorphism between the group of stable equivalence classes of symmetries with the cohomology group $H^3(G,U(1))$, consistent with previous conjectures. This amounts to a complete classification of locality preserving symmetries on spin chains. We further show that a locality preserving symmetry is stably equivalent to one that can be presented by finite depth quantum circuits with covariant gates if and only if the slant product of its anomaly is trivial in $H^2(G, U(1)[G])$.
title Classification of locality preserving symmetries on spin chains
topic Quantum Physics
Strongly Correlated Electrons
Mathematical Physics
url https://arxiv.org/abs/2503.15088