Thesis

### Problems in the quantum theory of many-particle systems

Abstract:

A finite temperature perturbation theory for the Heisenberg model of ferromagnetism is presented. A modified Wick's theorem proved for S=½ and finite temperatures allows the terms in the expansion for the temperature dependent Green's function to be expressed by linked Feynman-like diagrams. The diagrams differ from the usual boson and fermion diagrams in the appearance of time (temperature) dependent dotted lines between prop...

Peer review status:
Peer Reviewed

Files:
• (pdf, 2.5MB)

### Authors

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Department:
University of Oxford
Role:
Author
This thesis was digitised thanks to the generosity of Dr Leonard Polonsky More from this funder
Publication date:
1966
Type of award:
DPhil
Level of award:
Doctoral
Awarding institution:
University of Oxford
Local pid:
polonsky:11:6