Accessing thermodynamics from dynamical cluster-embedding approaches - Condensed Matter > Strongly Correlated ElectronsReport as inadecuate




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Abstract: Dynamical quantum-cluster approaches, such as different cluster extensions ofthe dynamical mean-field theory cluster DMFT or the variational clusterapproximation VCA, combined with efficient cluster solvers, such as thequantum Monte-Carlo QMC method, provide controlled approximations of thesingle-particle Green-s function for lattice models of strongly correlatedelectrons. To access the thermodynamics, however, a thermodynamical potentialis needed. We present an efficient numerical algorithm to compute the grandpotential within cluster-embedding approaches that are based on novelcontinuous-time QMC schemes: It is shown that the numerically exact clustergrand potential can be obtained from a quantum Wang-Landau technique toreweight the coefficients in the expansion of the partition function. Thelattice contributions to the grand potential are computed by a proper infinitesummation over Matsubara frequencies. A proof of principle is given by applyingthe VCA to antiferromagnetic short-range order in the two-dimensional Hubbardmodel at finite temperatures.



Author: Gang Li, Werner Hanke, Alexei N. Rubtsov, Sebastian Bäse, Michael Potthoff

Source: https://arxiv.org/







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