Related papers: Finite Temperature Effective Actions
A finite temperature many-particle theory of condensed matter systems is formulated using the functional Schroedinger picture. Using the interacting electron gas as a model system, we solve the equation of motion for the density matrix…
Scalar fields appear in many theories beyond the Standard Model of particle physics. In the early universe, they are exposed to extreme conditions, including high temperature and rapid cosmic expansion. Understanding their behavior in this…
Recent developments of perturbation theory at finite temperature based on effective field theory methods are reviewed. These methods allow the contributions from the different scales to be separated and the perturbative series to be…
We study the Schwinger mechanism by a uniform electric field in ${\rm dS}_2$ and ${\rm AdS}_2$ and the curvature effect on the Schwinger effect, and further propose a thermal interpretation of the Schwinger formula in terms of the…
The effective action and the mean fermion number density of graphene in constant external magnetic field at finite temperature and density are calculated. Closed expressions for these are given and their variation with temperature are…
Two different theoretical formulations of the finite temperature effects have been recently proposed for integrable field theories. In order to decide which of them is the correct one, we perform for a particular model an explicit check of…
We study numerically the finite temperature and frequency mobility of a particle coupled by a local interaction to a system of spinless fermions in one dimension. We find that when the model is integrable (particle mass equal to the mass of…
The heat kernel expansion for field theory at finite temperature is constructed. It is based on the imaginary time formalism and applies to generic Klein-Gordon operators in flat space-time. Full gauge invariance is manifest at each order…
We study the dynamical generation of masses for fundamental fermions in quenched quantum electrodynamics (qQED) at finite temperature in the bare vertex approximation, using Schwinger-Dyson equations (SDE). Motivated by perturbation theory,…
The parity-violating topological term in the effective action for 2+1 massive fermions is computed at finite temperature in the presence of a constant background field strength tensor. Gauge invariance of the finite-temperature effective…
Models incorporating moderately heavy dark matter (DM) typically need charged (scalar) fields to establish admissible relic densities. Since the DM freezes out at an early epoch, thermal corrections to the cross sections can be important.…
In this paper, we give a simple diagrammatic identification of the unique combination of the causal n-point vertex functions in the real time formalism that would coincide with the corresponding functions obtained in the imaginary time…
The early universe is dominated by phenomena at high temperatures. The thermal effects decrease during evolution of the universe. However there are some phenomena, such as processes inside stars and black holes, where the role of the…
Within the QED effective action approach, we study the propagation of low-frequency light at finite temperature. Starting from a general effective Lagrangian for slowly varying fields whose structure is solely dictated by Lorentz covariance…
We derive finite temperature time-dependent effective actions for the phase of the pairing field, which are appropriate for a 2D electron system with both non-retarded d- and s-wave attraction. As for s-wave pairing the d-wave effective…
Building on previous developments, we show that the Diagrammatic Monte Carlo technique allows to compute finite temperature response functions directly on the real-frequency axis within any field-theoretical formulation of the interacting…
The general correlations between massless fermions are calculated in the Schwinger model at arbitrary temperature. The zero temperature calculations on the plane are reviewed and clarified. Then the finite temperature fermionic Green's…
We derive the one-loop effective action for scalar, pseudoscalar, and electromagnetic fields coupled to a Dirac fermion in an extension of QED with Yukawa couplings. Using the Schwinger proper-time formalism and zeta-function…
We analyze the phemomenon of induced fermion number at finite temperature. At finite temperature, the induced fermion number $<N>$ is a thermal expectation value, and we compute the finite temperature fluctuations, $(\Delta…
Scalar fields at finite temperature are considered in four dimensional ultrastatic curved spacetime. One loop nonlocal effective action at finite temperature is found up to the second order in curvature expansion. This action is explicitly…