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Expectation values and density matrices in the Coupled‐Cluster theory
Author(s) -
Kümmel H. G.
Publication year - 1983
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560240107
Subject(s) - coupled cluster , truncation (statistics) , trace (psycholinguistics) , wave function , cluster (spacecraft) , scheme (mathematics) , norm (philosophy) , statistical physics , probability density function , mathematics , function (biology) , physics , mathematical analysis , quantum mechanics , computer science , statistics , molecule , linguistics , philosophy , evolutionary biology , political science , law , biology , programming language
A scheme for calculating expectation values in coupled‐cluster wave functions is given. The unlinked terms originating from the norm of the wave function are eliminated. Hermiticity and trace conditions for the density matrices are exhibited in such a way as to guarantee their conservation in any reasonable truncation scheme.