Damping rate of a fast fermion in hot QED

Baier, Rudolf; Kobes, R.

doi:10.1103/physrevd.50.5944

Cited by 24 publications

(13 citation statements)

References 31 publications

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“…Further studies of the spectral function questioned the validity of the quasiparticle approximation and the exponential relaxation associated with a damping rate [30,31]. Although these studies provided an understanding of the failure of the quasiparticle picture (exponential relaxation) for hard fermions, the issue of the relaxation time scales was only recently clarified by the implementation of a Bloch-Nordsieck resummation of the infrared divergent diagrams [32,33] which yields anomalous logarithmic relaxation.…”

Section: Introductionmentioning

confidence: 99%

Dynamical renormalization group resummation of finite temperature infrared divergences

et al. 1999

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We introduce the method of dynamical renormalization group to study relaxation and damping out of equilibrium directly in real time and applied it to the study of infrared divergences in scalar QED. This method allows a consistent resummation of infrared effects associated with the exchange of quasistatic transverse photons and leads to anomalous logarithmic relaxation of the form e −α T t ln[t/t 0 ] for hard momentum charged excitations. This is in contrast with the usual quasiparticle interpretation of charged collective excitations at finite temperature in the sense of exponential relaxation of a narrow width resonance for which the width is the imaginary part of the self-energy on-shell. In the case of narrow resonances away from thresholds, this approach leads to the usual exponential relaxation. The hard thermal loop resummation program is incorporated consistently into the dynamical renormalization group yielding a picture of relaxation and damping phenomena in a plasma in real time that trascends the conceptual limitations of the quasiparticle picture and other type of resummation schemes.12.38. Mh,11.15.Bt

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Section: Introductionmentioning

confidence: 99%

Dynamical renormalization group resummation of finite temperature infrared divergences

et al. 1999

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“…Thus, in the lowest order calculations of Refs. [3], [15][16][17][18][19][20][21][22][23][24][25][26], one meets the same logarithmic divergence for electrons in QED, for charged scalars in SQED, and for quarks and gluons in QCD. (There is no such problem for the photon damping rate, which is IR finite and of order g 4 T [28], since photons do not couple directly to gluons or to themselves.)…”

Section: Introductionmentioning

confidence: 99%

Lifetimes of quasiparticles and collective excitations in hot QED plasmas

1997

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The perturbative calculation of the lifetime of fermion excitations in a QED plasma at high temperature is plagued with infrared divergences which are not eliminated by the screening corrections. The physical processes responsible for these divergences are the collisions involving the exchange of long wavelength, quasistatic, magnetic photons, which are not screened by plasma effects. The leading divergences can be resummed in a nonperturbative treatment based on a generalization of the Bloch-Nordsieck ͑BN͒ model at finite temperature. The resulting expression of the fermion propagator is free of infrared problems, and exhibits a nonexponential damping at large times: S R (t)ϳexp͕Ϫ␣Tt ln p t͖, where p ϭeT/3 is the plasma frequency and ␣ϭe 2 /4. ͓S0556-2821͑97͒00802-3͔

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“…Damping rates of hard particles in a relativistic plasma at high temperature attracted much interest recently [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. For instance, the damping rate of a quark in a QCD plasma is related to important quantities of the quark-gluon plasma, such as mean free paths, thermalization times [18,20], viscosity [18,21], and stopping power [5,7,[22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%