Remarks on transient photon production in heavy ion collisions

@inproceedings{Fraga2008RemarksOT,
  title={Remarks on transient photon production in heavy ion collisions},
  author={Eduardo Souza Fraga and François Gelis and Dominique Schiff},
  year={2008}
}
In this note, we discuss the derivation of a formula that has been used in the literature in order to compute the number of photons emitted by a hot or dense system during a finite time. Our derivation is based on a variation of the standard operator-based S-matrix approach. The shortcomings of this formula are then emphasized, which leads to a negative conclusion concerning the possibility of using it to predict transient effects for the photon rate.