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A variational perturbation scheme for many-particle systems in the functional integral approach

Sang Koo You·Chul Koo Kim·Kyun Nahm·Hyun Sik Noh
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Abstract

A variational Perturbation theory based on the functional integral approach is formulated for many-particle systems. Using the variational action obtained through Jensen-Peierls' inequality, a perturbative expansion scheme for the thermodynamic potential is established. A modified Wick's theorem is obtained for the variational perturbation expansions. This theorem allows one to carry out systematic calculations of higher order terms without worrying about the double counting problem. A model numerical calculation was carried out on a nucleon gas system interacting through the Yukawa-type potential to test the efficiency of the present method.

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Sang Koo You, Chul Koo Kim, Kyun Nahm, Hyun Sik Noh. 2000-07-17. A variational perturbation scheme for many-particle systems in the functional integral approach. https://doi.org/10.1103/physrevc.62.045503

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