Two-particle calculations with quantics tensor trains: Solving the parquet equations

We present an application of quantics tensor trains (QTTs) and tensor cross interpolation (TCI) to the solution of a full set of self-consistent equations for multivariate functions, the so-called parquet equations. We show that the steps needed to evaluate the equations (Bethe-Salpeter equations, p...

Full description

Saved in:
Bibliographic Details
Main Authors: Stefan Rohshap, Marc K. Ritter, Hiroshi Shinaoka, Jan von Delft, Markus Wallerberger, Anna Kauch
Format: Article
Language:English
Published: American Physical Society 2025-04-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.7.023087
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850155603266109440
author Stefan Rohshap
Marc K. Ritter
Hiroshi Shinaoka
Jan von Delft
Markus Wallerberger
Anna Kauch
author_facet Stefan Rohshap
Marc K. Ritter
Hiroshi Shinaoka
Jan von Delft
Markus Wallerberger
Anna Kauch
author_sort Stefan Rohshap
collection DOAJ
description We present an application of quantics tensor trains (QTTs) and tensor cross interpolation (TCI) to the solution of a full set of self-consistent equations for multivariate functions, the so-called parquet equations. We show that the steps needed to evaluate the equations (Bethe-Salpeter equations, parquet equation, and Schwinger-Dyson equation) can be decomposed into basic operations on the QTT-TCI compressed objects. The repeated application of these operations does not lead to a loss of accuracy beyond a specified tolerance and the iterative scheme converges even for numerically demanding parameters. As examples, we take the Hubbard model in the atomic limit and the single impurity Anderson model, where the basic objects in parquet equations, the two-particle vertices, depend on three frequencies, but not on momenta. The results show that this approach is able to overcome major computational bottlenecks of standard numerical methods. The applied methods allow for an exponential increase of the number of grid points included in the calculations, and a corresponding exponential reduction of the computational error, for a linear increase in computational cost.
format Article
id doaj-art-fbbe9a7f01ce43b089c67f3f955fb923
institution OA Journals
issn 2643-1564
language English
publishDate 2025-04-01
publisher American Physical Society
record_format Article
series Physical Review Research
spelling doaj-art-fbbe9a7f01ce43b089c67f3f955fb9232025-08-20T02:24:51ZengAmerican Physical SocietyPhysical Review Research2643-15642025-04-017202308710.1103/PhysRevResearch.7.023087Two-particle calculations with quantics tensor trains: Solving the parquet equationsStefan RohshapMarc K. RitterHiroshi ShinaokaJan von DelftMarkus WallerbergerAnna KauchWe present an application of quantics tensor trains (QTTs) and tensor cross interpolation (TCI) to the solution of a full set of self-consistent equations for multivariate functions, the so-called parquet equations. We show that the steps needed to evaluate the equations (Bethe-Salpeter equations, parquet equation, and Schwinger-Dyson equation) can be decomposed into basic operations on the QTT-TCI compressed objects. The repeated application of these operations does not lead to a loss of accuracy beyond a specified tolerance and the iterative scheme converges even for numerically demanding parameters. As examples, we take the Hubbard model in the atomic limit and the single impurity Anderson model, where the basic objects in parquet equations, the two-particle vertices, depend on three frequencies, but not on momenta. The results show that this approach is able to overcome major computational bottlenecks of standard numerical methods. The applied methods allow for an exponential increase of the number of grid points included in the calculations, and a corresponding exponential reduction of the computational error, for a linear increase in computational cost.http://doi.org/10.1103/PhysRevResearch.7.023087
spellingShingle Stefan Rohshap
Marc K. Ritter
Hiroshi Shinaoka
Jan von Delft
Markus Wallerberger
Anna Kauch
Two-particle calculations with quantics tensor trains: Solving the parquet equations
Physical Review Research
title Two-particle calculations with quantics tensor trains: Solving the parquet equations
title_full Two-particle calculations with quantics tensor trains: Solving the parquet equations
title_fullStr Two-particle calculations with quantics tensor trains: Solving the parquet equations
title_full_unstemmed Two-particle calculations with quantics tensor trains: Solving the parquet equations
title_short Two-particle calculations with quantics tensor trains: Solving the parquet equations
title_sort two particle calculations with quantics tensor trains solving the parquet equations
url http://doi.org/10.1103/PhysRevResearch.7.023087
work_keys_str_mv AT stefanrohshap twoparticlecalculationswithquanticstensortrainssolvingtheparquetequations
AT marckritter twoparticlecalculationswithquanticstensortrainssolvingtheparquetequations
AT hiroshishinaoka twoparticlecalculationswithquanticstensortrainssolvingtheparquetequations
AT janvondelft twoparticlecalculationswithquanticstensortrainssolvingtheparquetequations
AT markuswallerberger twoparticlecalculationswithquanticstensortrainssolvingtheparquetequations
AT annakauch twoparticlecalculationswithquanticstensortrainssolvingtheparquetequations