Retarded Green{close_quote}s functions and forward scattering amplitudes in thermal field theory

Journal Article · Mon Mar 01 04:00:00 EST 1999 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.59.065004· OSTI ID:321557

Brandt, F T; Frenkel, J; da Silva, A J ^[1]; Das, A ^[2]

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1. Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, Sao Paulo 05315-970 (Brazil)
2. Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States)

In this paper, we give a simple diagrammatic identification of the unique combination of the causal {ital n}-point vertex functions in the real time formalism that would coincide with the corresponding functions obtained in the imaginary time formalism. Furthermore, we give a simple calculational method for evaluating the temperature dependent parts of the retarded vertex functions, to one loop, by identifying them with the forward scattering amplitudes of on-shell thermal particles. As an application of the method, we calculate and show that the temperature-dependent parts of all the retarded functions vanish at one loop order for (1+1)-dimensional massless QED. We further point out that, in this model, in fact, the temperature-dependent parts of all the retarded vertex functions vanish to all orders in perturbation theory. {copyright} {ital 1999} {ital The American Physical Society}

• OSTI ID: 321557
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 6 Vol. 59; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
DIAGRAMS
GREEN FUNCTION
PERTURBATION THEORY
QUANTUM ELECTRODYNAMICS
QUANTUM FIELD THEORY
SCATTERING AMPLITUDES
VERTEX FUNCTIONS