Relation between real-time and imaginary-time formalisms of finite-temperature quantum field theory

Journal Article · Mon Mar 15 00:00:00 EST 1993 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.47.2622· OSTI ID:6700492

Xu, H ^[1]

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1. Chinese Center of Advanced Science and Technology (World Laboratory), P.O. Box 8730, Beijing 100080 (China) Institute of Condensed Matter Physics and Department of Physics, Shanghai 200030 (China)

Perturbative structures of finite-temperature quantum field theory are studied at a fundamental level. It is shown that the real-time formalism based on the Keldysh expansion and the imaginary-time formalism are related by a unitary transformation, and therefore are physically equivalent provided both of them are expressed in retarded form. On the other hand it is impossible for the thermo field dynamics to be reformulated in terms of retarded functions in conformity with the imaginary-time formalism due to the lack of unitary equivalence with the Keldysh and the imaginary-time formalisms which arises from its choice of path in the complex-time plane.

• OSTI ID: 6700492
• Journal Information: Physical Review, D (Particles Fields); (United States), Vol. 47:6; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
QUANTUM FIELD THEORY
TEMPERATURE DEPENDENCE
EQUATIONS OF MOTION
GREEN FUNCTION
HAMILTONIANS
HEISENBERG PICTURE
PERTURBATION THEORY
SCHROEDINGER PICTURE
SELF-ENERGY
DIFFERENTIAL EQUATIONS
ENERGY
EQUATIONS
FIELD THEORIES
FUNCTIONS
MATHEMATICAL OPERATORS
PARTIAL DIFFERENTIAL EQUATIONS
QUANTUM OPERATORS
662110* - General Theory of Particles & Fields- Theory of Fields & Strings- (1992-)
661100 - Classical & Quantum Mechanics- (1992-)