Damping Rate of a Massive Fermion in a Hot Medium

Abstract

In a hot system every excitation acquires a finite lifetime, manifesting itself in a non-zero spectral width. Ordinary damping as well as quantum memory effects arise from this nontrivial spectral function. This report presents a new method for the self-consistent calculation of the spectral width of a fermion coupled to massless bosons of scalar, vector and pseudoscalar type. In accordance with the known procedures of Quantum Electrodynamics, the self-consistent summation of the corresponding Fock diagram eliminates all infrared divergences although the bosons are not screened at all. The solutions for the fermion damping rate are analytical in the coupling constant g , but not analytical in the temperature parameter, i.e., γ ∝ g 2 T + O(g 4 T log(T /M )) .

Quantum sensing of open systems: Estimation of damping constants and temperature

“…However, sometimes these processes may yield important information on the system. The damping rate of a particle moving in a medium may allow the estimation of the quantum memory time and radiation properties [22]. Absorption spectroscopy has a wide range of applications, in remote sensing [23], in chemistry and atomic physics [24], in astronomy [25], and in the characterization of materials, not only at the macroscopic level but also for microscopic systems, like cells and organelles [26].…”