Variational cluster approach to spontaneous symmetry breaking: The itinerant antiferromagnet in two dimensions

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dc.creatorDahnken, C.
dc.creatorAichhorn, M.
dc.creatorHanke, W.
dc.creatorArrigoni, E.
dc.creatorPotthoff, M.
dc.date2003-09-17
dc.date2004-09-01
dc.date.accessioned2026-07-07T02:53:31Z
dc.date.available2026-07-07T02:53:31Z
dc.descriptionBased on the self-energy-functional approach proposed recently [M. Potthoff, Eur. Phys. J. B 32, 429 (2003)], we present an extension of the cluster-perturbation theory to systems with spontaneously broken symmetry. Our method applies to models with local interactions and accounts for both short-range correlations and long-range order. Short-range correlations are accurately taken into account via exact diagonalization of finite clusters. Long-range order is described by variational optimization of a ficticious symmetry-breaking field. In comparison with related cluster methods, our approach is more flexible and, for a given cluster size, less demanding numerically, especially at zero temperature. An application of the method to the antiferromagnetic phase of the Hubbard model at half-filling shows good agreement with results from quantum Monte-Carlo calculations. We demonstrate that the variational extension of the cluster-perturbation theory is crucial to reproduce salient features of the single-particle spectrum.
dc.description13 pages, accepted by PRB, v2 with minor changes
dc.identifierhttps://arxiv.org/abs/cond-mat/0309407
dc.identifierhttp://arxiv.org/abs/cond-mat/0309407
dc.identifierPhys. Rev. B 70, 245110 (2004)
dc.identifierdoi:10.1103/PhysRevB.70.245110
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/22243
dc.subjectStrongly Correlated Electrons
dc.subjectSuperconductivity
dc.titleVariational cluster approach to spontaneous symmetry breaking: The itinerant antiferromagnet in two dimensions
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