Titel
Simulating thermal density operators with cluster expansions and tensor networks
Autor*in
David Devoogdt
Ghent University
Frank Verstraete
Ghent University
... show all
Abstract
We provide an efficient approximation for the exponential of a local operator in quantum spin systems using tensor-network representations of a cluster expansion. We benchmark this cluster tensor network operator (cluster TNO) for one-dimensional systems, and show that the approximation works well for large real- or imaginary-time steps. We use this formalism for representing the thermal density operator of a two-dimensional quantum spin system at a certain temperature as a single cluster TNO, which we can then contract by standard contraction methods for two-dimensional tensor networks. We apply this approach to the thermal phase transition of the transverse-field Ising model on the square lattice, and we find through a scaling analysis that the cluster-TNO approximation gives rise to a continuous phase transition in the correct universality class; by increasing the order of the cluster expansion we find good values of the critical point up to surprisingly low temperatures.
Stichwort
General Physics and Astronomy
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
Erschienen in
Titel
SciPost Physics
Band
14
Ausgabe
4
ISSN
2542-4653
Erscheinungsdatum
2023
Publication
Stichting SciPost
Erscheinungsdatum
2023
Zugänglichkeit
Rechte
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