Correlation density matrices for 1- dimensional quantum chains based on the density matrix renormalization group - Condensed Matter > Strongly Correlated ElectronsReport as inadecuate




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Abstract: A useful concept for finding numerically the dominant correlations of a givenground state in an interacting quantum lattice system in an unbiased way is thecorrelation density matrix. For two disjoint, separated clusters, it is definedto be the density matrix of their union minus the direct product of theirindividual density matrices and contains all correlations between the twoclusters. We show how to extract from the correlation density matrix a generaloverview of the correlations as well as detailed information on the operatorscarrying long-range correlations and the spatial dependence of theircorrelation functions. To determine the correlation density matrix, wecalculate the ground state for a class of spinless extended Hubbard modelsusing the density matrix renormalization group. This numerical method is basedon matrix product states for which the correlation density matrix can beobtained straightforwardly. In an appendix, we give a detailed tutorialintroduction to our variational matrix product state approach for ground statecalculations for 1- dimensional quantum chain models. We show in detail howmatrix product states overcome the problem of large Hilbert space dimensions inthese models and describe all techniques which are needed for handling them inpractice.



Author: W. M√ľnder 1, A. Weichselbaum 1, A. Holzner 1, J. von Delft 1, C. L. Henley 2 1 Physics Department, Arnold Sommerfeld Center for

Source: https://arxiv.org/







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