4 papers · 1 filter
A Simple Derivation of the Hard Thermal Loop Effective Action
Per Elmfors, T. H. Hansson, Ismail Zahed
We use the background field method along with a special gauge condition, to derive the hard thermal loop effective action in a simple manner. The new point in the paper is to relat…
Derivatives as an IR Regulator for Massless Fields
Per Elmfors
The free propagator for the scalar --theory is calculated exactly up to the second derivative of a background field. Using this propagator I compute the one--loop effective a…
Electromagnetic Fields in a Thermal Background
Per Elmfors, Bo-Sture Skagerstam
The one--loop effective action for a slowly varying electromagnetic field is computed at finite temperature and density using a real-time formalism. We discuss the gauge invariance…
Generalizations of the thermal Bogoliubov transformation
P. Elmfors, H. Umezawa
The thermal Bogoliubov transformation in thermo field dynamics is generalized in two respects. First, a generalization of the --degree of freedom to tilde non--conserving repres…