Autor: |
Whitlock, P. A., Kalos, M. H., Chester, G. V. |
Zdroj: |
Journal of Statistical Physics; August 1983, Vol. 32 Issue: 2 p389-405, 17p |
Abstrakt: |
A Schwinger variational principle has been derived for use in quantum, manybody systems at finite temperatures. The variational principle is a stationary expression for the density matrix which may be iterated to improve an approximate density matrix. It also can be used to find stationary expressions for observables. If an approximate, parametrized density matrix is used, the parameters are varied to find the regions where the variational principle is stationary. The variational density matrix obtained with the optimal parameters can be regarded as optimal for that observable. The method has been applied to two model problems, a particle in a box and two hard spheres at finite temperatures. The advantages and shortcomings of the method are discussed. |
Databáze: |
Supplemental Index |
Externí odkaz: |
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