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Correlation strength and information entropy
Author(s) -
Ziesche Paul
Publication year - 1995
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.560560422
Subject(s) - statistical physics , fermi gas , ground state , correlation , density matrix , eigenvalues and eigenvectors , entropy (arrow of time) , physics , cumulant , electronic correlation , wave function , correlation function (quantum field theory) , fermi gamma ray space telescope , quantum mechanics , electron , mathematics , statistics , geometry , quantum , dielectric
The correlation present in the nondegenerate ground state of an interacting Fermi system is discussed in terms of reduced density matrices and their cumulant expansion. By generalizing a result obtained for the interacting uniform electron gas (correlation induced exchange‐hole narrowing), possible measures of the correlation strength in terms of natural occupation numbers (the eigenvalues of the true one‐particle density matrix) are introduced. These quantities‐the v ‐order nonidempotency and the information entropy of the natural occupation numbers‐result from the correlated many‐body wave function and characterize the ground‐state correlation in addition to the usual correlation energy. The uniform electron gas serves as a first illustrative example. © 1995 John Wiley & Sons, Inc.