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arXiv · 1003.0246

Density-matrix formalism with three-body ground-state correlations

Mitsuru Tohyama·Peter Schuck
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Abstract

A density-matrix formalism which includes the effects of three-body ground- state correlations is applied to the standard Lipkin model. The reason to consider the complicated three-body correlations is that the truncation scheme of reduced density matrices up to the two-body level does not give satisfactory results to the standard Lipkin model. It is shown that inclusion of the three-body correlations drastically improves the properties of the ground states and excited states. It is pointed out that lack of mean-field effects in the standard Lipkin model enhances the relative importance of the three-body ground-state correlations. Formal aspects of the density-matrix formalism such as a relation to the variational principle and the stability condition of the ground state are also discussed. It is pointed out that the three-body ground-state correlations are necessary to satisfy the stability condition.

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Mitsuru Tohyama, Peter Schuck. 2010-03-01. Density-matrix formalism with three-body ground-state correlations. https://doi.org/10.1140/epja%2Fi2010-11002-5

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