The Quantum Field Theory of the Ensemble Operator

Journal Article · Mon Mar 09 04:00:00 EDT 2009 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3108378· OSTI ID:21293365

Porter, Richard N ^[1]

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1. Department of Chemistry, State University of New York, Stony Brook, New York, 11794-3400 (United States)

Quantum field theory (QFT) provides a systematic investigative tool for ensembles of molecules. The grand-canonical ensemble operator (GCEO) for an ideal gas is presented in terms of the Fock creation and annihilation operators. The ideal GCEO can be shown to obey a simple equation which facilitates calculation of quantum-statistical properties of bosonic and fermionic molecules. Examples are linked-cluster QFT derivations of the grand-canonical partition function and the Poisson distribution for non-interacting molecules. The Boltzmann limit is achieved by omitting exchange diagrams. Summations of Feynman diagrams for long- and short-range interactions to infinite order lead to a useful model of the pair-correlation function and a new avenue for the study of dynamics near the critical point for gas-liquid phase transitions.

• OSTI ID: 21293365
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1102; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNIHILATION OPERATORS
BOSONS
CORRELATION FUNCTIONS
CREATION OPERATORS
FERMIONS
FEYNMAN DIAGRAM
GASES
INTERACTION RANGE
LIQUIDS
MOLECULES
PARTITION FUNCTIONS
PHASE TRANSFORMATIONS
QUANTUM FIELD THEORY
QUANTUM MECHANICS