Path-integral formulation of real-time finite-temperature field theory

Kobes, R.; Kowalski, K. L.

doi:10.1103/physrevd.34.513

Cited by 60 publications

(24 citation statements)

References 11 publications

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“…We treat the term φ 2 (t)(ψ ± ) 2 as perturbation, along with the linear, cubic and quartic terms. The conditions ψ ± (x, t) = 0 (22) will give rise to the effective non-equilibrium equations of motion for the background field. This is the generalization of the "tadpole" method [28] to non-equilibrium field theory.…”

Section: Amplitude Expansion 221 Discrete Symmetrymentioning

confidence: 99%

Dissipation via particle production in scalar field theories

et al. 1995

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We study the nonequilibrium evolution of the expectation value of a scalar field in the broken and unbroken symmetry cases. We find that the particles produced by parametric amplification give rise to dissipative behavior for this mode. However, a l?d type of term cannot account for the dissipational dynamics. We are able to show clearly that perturbation theory breaks down at late times, so that dissipation in field theories can only be understood nonperturbatively. When Goldstone bosons are present we find infrared divergences that require a nonperturbative resummation to describe the long-time dynamics. We use the Hartree factorization and the large N approximation to the O(N) linear a model to numerically as well as analytically understand the long-time behavior of the zero mode as well as that of the produced particles. The O(N) model case is extremely interesting since, in the spontaneously broken case, the radial mode dissipates all of its energy into production of longwavelength Goldstone modes. The minima of the effective action (determined by the final value of the expectation value of the scalar field) depend on the initial conditions.

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Section: Amplitude Expansion 221 Discrete Symmetrymentioning

confidence: 99%

Dissipation via particle production in scalar field theories

et al. 1995

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“…To our knowledge the first to introduce this formulation were Schwinger [30] and Keldysh [31] (for an early account see Mills [32]). There are many clear articles in the literature using this techniques to study real time correlation functions [28,29,[33][34][35][36][37].…”

Section: Statistical Mechanics Out Of Equilibriummentioning

confidence: 99%

Phase transitions out of equilibrium: Domain formation and growth

1993

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We study the dynamics of phase transitions out of equilibrium in weakly coupled scalar field theories. We consider the case in which there is a rapid supercooling from an initial symmetric phase in thermal equilibrium at temperature T i > T c to a final state at low temperature T f ≈ 0. In particular we study the formation and growth of correlated domains out of equilibrium. It is shown that the dynamics of the process of domain formation and growth (spinodal decomposition) cannot be studied in perturbation theory, and a non-perturbative self-consistent Hartree approximation is used to study the long time evolution. We find in weakly coupled theories that the size of domains grow at long times as ξ D (t) ≈ tξ(0). The size of the domains and the amplitude of the fluctuations grow up to a maximum time t s which in weakly coupled theories is estimated to bewith ξ(0) the zero temperature correlation length. For very weakly coupled the-1 ories, their final size is several times the zero temperature correlation length. For strongly coupled theories the final size of the domains is comparable to the zero temperature correlation length and the transition proceeds faster.

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“…As a framework for a first principle analysis, thermo field dynamics was largely developed by Matsumoto et al [10] while a detailed investigation of QFTs at finite temperatures for real times was made by Niemi and Semenoff [11]. Comprehensive outlines of the path-integral treatment of quantum fields in a thermal medium may be found in [11][12][13], and much of the theoretical concepts presented in this review draws upon that work. Three years before the work of Kobes and Kowalski [12], Weldon [14] provided self-energy calculations performed using the Matsubara formalism and presented a condensed and clear overview and interpretation of the thermal decay rates.…”

Section: Introductionmentioning

confidence: 99%

Thermal Field Theory in real-time formalism: concepts and applications for particle decays

Lundberg

Pasechnik

2021

Eur. Phys. J. A

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This review represents a detailed and comprehensive discussion of the Thermal Field Theory (TFT) concepts and key results in Yukawa-type theories. We start with a general pedagogical introduction into the TFT in the imaginary- and real-time formulation. As phenomenologically relevant implications, we present a compendium of thermal decay rates for several typical reactions calculated within the framework of the real-time formalism and compared to the imaginary-time results found in the literature. Processes considered here are those of a neutral (pseudo)scalar decaying into two distinct (pseudo)scalars or into a fermion-antifermion pair. These processes are extended from earlier works to include chemical potentials and distinct species in the final state. In addition, a (pseudo)scalar emission off a fermion line is also discussed. These results demonstrate the importance of thermal effects in particle decay observables relevant in many phenomenological applications in systems at high temperatures and densities.

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Path-integral formulation of real-time finite-temperature field theory

Cited by 60 publications

References 11 publications

Dissipation via particle production in scalar field theories

Dissipation via particle production in scalar field theories

Phase transitions out of equilibrium: Domain formation and growth

Thermal Field Theory in real-time formalism: concepts and applications for particle decays

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