Real-frequency diagrammatic Monte Carlo at finite temperature

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dc.citation.issue7
dc.citation.rankM21
dc.citation.spage075113
dc.citation.volume101
dc.contributor.authorVučičević, Jakša
dc.contributor.authorFerrero, Michel
dc.date.accessioned2024-06-18T10:28:54Z
dc.date.available2024-06-18T10:28:54Z
dc.date.issued2020-02-12
dc.description.abstractDiagrammatic expansions are a central tool for treating correlated electron systems. At thermal equilibrium, they are most naturally defined within the Matsubara formalism. However, extracting any dynamic response function from a Matsubara calculation ultimately requires the ill-defined analytical continuation from the imaginary-to the real-frequency domain. It was recently proposed [A. Taheridehkordi, Phys. Rev. B 99, 035120 (2019)2469-995010.1103/PhysRevB.99.035120] that the internal Matsubara summations of any interaction-expansion diagram can be performed analytically by using symbolic algebra algorithms. The result of the summations is then an analytical function of the complex frequency rather than Matsubara frequency. Here we apply this principle and develop a diagrammatic Monte Carlo technique which yields results directly on the real-frequency axis. We present results for the self-energy ς(ω) of the doped 32×32 cyclic square-lattice Hubbard model in a nontrivial parameter regime, where signatures of the pseudogap appear close to the antinode. We discuss the behavior of the perturbation series on the real-frequency axis and in particular show that one must be very careful when using the maximum entropy method on truncated perturbation series. Our approach holds great promise for future application in cases when analytical continuation is difficult and moderate-order perturbation theory may be sufficient to converge the result.
dc.identifier.doi10.1103/physrevb.101.075113
dc.identifier.issn2469-9950
dc.identifier.issn2469-9969
dc.identifier.scopus2-s2.0-85079771286
dc.identifier.urihttps://pub.ipb.ac.rs/handle/123456789/117
dc.identifier.wos000513211600002
dc.language.isoen
dc.publisherAmerican Physical Society (APS)
dc.relation.ispartofPhysical Review B
dc.relation.ispartofabbrPhys. Rev. B
dc.rightsrestrictedAccess
dc.titleReal-frequency diagrammatic Monte Carlo at finite temperature
dc.typeArticle
dc.type.versionpublishedVersion
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