Related papers: Improved hard-thermal-loop effective action for ho…
Summation over hard thermal loops, by themselves and as insertions in higher order Feynman diagrams, is important in thermal perturbation theory for Quantum Chromodynamics, so that all contributions of a given order in the coupling constant…
I review recent developments in QCD thermodynamics and collective excitations from the hard-thermal-loop effective theory. I begin by motivating the discussion with open questions from heavy-ion collisions. I then discuss a…
We derive the hard thermal loop action for soft electromagnetic fields in the finite temperature world-line formulation at imaginary time, by first integrating out the hard fermion modes from the microscopic QED action. Further, using the…
It is shown how the hard thermal loop approximation can be used in chiral perturbation theory to study some thermal properties of Goldstone bosons. Hard thermal effects are first studied in the non-linear sigma model. Then those results are…
We present a systematic discussion of Braaten and Pisarski's hard thermal loop (HTL) effective theory within the framework of the real-time (Schwinger-Keldysh) formalism. As is well known, the standard imaginary-time HTL amplitudes for hot…
The hard thermal loop effective action for Goldstone bosons is deduced by symmetry arguments from the corresponding result for gauge bosons. Pseudoscalar mesons in Chromodynamics and magnons in an antiferromagnet are discussed as special…
The conventional weak-coupling expansion for thermodynamic quantities in hot field theories shows poor convergence unless the coupling constant is tiny. I discuss screened perturbation theory (SPT) which is a way of reorganizing the…
In this review, we present the key aspects of modern thermal perturbation theory based on the hard thermal loop (HTL) approximation, including its theoretical foundations and applications within quantum electrodynamics (QED) and quantum…
We derive a closed form expression for the long wavelength limit of the effective action for hard thermal loops in an external gravitational field. It is a function of the metric, independent of time derivatives. It is compared and…
Thermal field theory is indispensable for describing hot and dense systems. Yet perturbative calculations are often stymied by a host of energy scales, and tend to converge slowly. This means that precise results require the apt use of…
The successive perturbative estimates of the pressure of QCD at high temperature T show no sign of convergence, unless the coupling constant g is unrealistically small. Exploiting known results of an effective field theory which separates…
Starting from the Phi-derivable approximation scheme at leading-loop order, the thermodynamical potential in a hot scalar theory, as well as in QED and QCD, is expressed in terms of hard thermal loop propagators. This nonperturbative…
We compute the one loop effective action for a Quantum Field Theory at finite temperature, in the presence of background gauge fields, employing the Heat-Kernel method. This method enables us to compute the thermal corrections to the Wilson…
We determine the 2-loop effective gauge coupling of QCD at high temperatures, defined as a matching coefficient appearing in the dimensionally reduced effective field theory. The result allows to improve on one of the classic…
The effective actions of gauge bosons, fermions and scalars, which are obtained within the hard-loop approximation, are shown to have unique forms for a whole class of gauge theories including QED, scalar QED, super QED, pure Yang-Mills,…
High-temperature resummed perturbation theory is plagued by poor convergence properties. The problem appears for theories with bosonic field content such as QCD, QED or scalar theories. We calculate the pressure as well as other…
The production rate of soft real photons or soft lepton pairs by a hot QCD plasma is dominated by strong collinear divergences. As a consequence, it appears that the effective theory based on the resummation of hard thermal loops fails to…
We consider a scalar massless quantum field model, at finite temperature $T$, both renormalizable and asymptotically free. Focussing on the singular structure of the effective perturbation theory about the light cone, several new insights…
It is argued that in hot gauge field theories, "Hard Thermal Loops" leading order calculations call for a definite sequence of angular averages and discontinuity (or Imaginary part prescription) operations, and run otherwise into incorrect…
We study, in the imaginary-time formalism, the high temperature behavior of n-point thermal loops in static Yang-Mills and gravitational fields. We show that in this regime, any hard thermal loop gives the same leading contribution as the…