1975/11/21 by P Lloyd, P R Best · 1 citation
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Quantum many-body systems #Theoretical and Computational Physics
paper · doi:10.1088/0022-3719/8/22/015
crossref issued 1975/11/21 · crossref published 1975/11/21 · crossref published-print 1975/11/21 · openalex publication_date 1975/11/21 · crossref published-online 2001/02/06 · crossref created 2002/07/26 · crossref deposited 2020/04/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30 · crossref indexed 2026/08/03
An exact variational principle involving the density-of-eigenstates function is derived. This variational principle differs from previously published conjectures, and has been applied to two different types of band-tailing problems in order to demonstrate its usefulness. A closely related variational ansatz concerning the complex self-energy of a random medium is then formulated, and is shown, under the appropriate circumstances, to lead to the CPA approximation as well as to cluster generalizations of this approximation. It is shown that such cluster generalizations can accurately reproduce some computer-generated density of states.