1,337 research outputs found
Chiral Phase Transitions in QCD at Finite Temperature: Hard-Thermal-Loop Resummed Dyson-Schwinger Equation in the Real Time Formalism
Chiral phase transition in thermal QCD is studied by using the
Dyson-Schwinger (DS) equation in the real time hard thermal loop approximation.
Our results on the critical temperature and the critical coupling are
significantly different from those in the preceding analyses in the ladder DS
equation, showing the importance of properly taking into account the essential
thermal effects, namely the Landau damping and the unstable nature of thermal
quasiparticles.Comment: 4 pages including 2 figures (ps file), to appear in the proceedings
of the 4th International Conference on Physics and Astrophysics of
Quark-Gluon Plasma (ICPAQGP-2001), 26-30 November 2001, Jaipur, Indi
Light-front Schwinger Model at Finite Temperature
We study the light-front Schwinger model at finite temperature following the
recent proposal in \cite{alves}. We show that the calculations are carried out
efficiently by working with the full propagator for the fermion, which also
avoids subtleties that arise with light-front regularizations. We demonstrate
this with the calculation of the zero temperature anomaly. We show that
temperature dependent corrections to the anomaly vanish, consistent with the
results from the calculations in the conventional quantization. The gauge
self-energy is seen to have the expected non-analytic behavior at finite
temperature, but does not quite coincide with the conventional results.
However, the two structures are exactly the same on-shell. We show that
temperature does not modify the bound state equations and that the fermion
condensate has the same behavior at finite temperature as that obtained in the
conventional quantization.Comment: 10 pages, one figure, version to be published in Phys. Rev.
Gauge Independence of Limiting Cases of One-Loop Electron Dispersion Relation in High-Temperature QED
Assuming high temperature and taking subleading temperature dependence into
account, gauge dependence of one-loop electron dispersion relation is
investigated in massless QED at zero chemical potential. The analysis is
carried out using a general linear covariant gauge. The equation governing the
gauge dependence of the dispersion relation is obtained and used to prove that
the dispersion relation is gauge independent in the limiting case of momenta
much larger than . It is also shown that the effective mass is not
influenced by the leading temperature dependence of the gauge dependent part of
the effective self-energy. As a result the effective mass, which is of order
, does not receive a correction of order from one loop, independent
of the gauge parameter.Comment: Revised and enlarged version, 14 pages, Revte
On finite--temperature and --density radiative corrections to the neutrino effective potential in the early Universe
Finite-temperature and -density radiative corrections to the neutrino
effective potential in the otherwise CP-symmetric early Universe are considered
in the real-time approach of Thermal Field Theory. A consistent perturbation
theory endowed with the hard thermal loop resummation techniques developed by
Braaten and Pisarski is applied. Special attention is focused on the question
whether such corrections can generate any nonzero contribution to the
CP-symmetric part of the neutrino potential, if the contact approximation for
the W-propagator is used.Comment: 11 pages, revtex styl
THERMAL EFFECTS ON THE CATALYSIS BY A MAGNETIC FIELD
We show that the formation of condensates in the presence of a constant
magnetic field in 2+1 dimensions is extremely unstable. It disappears as soon
as a heat bath is introduced with or without a chemical potential. We point out
some new nonanalytic behavior that develops in this system at finite
temperature.Comment: 10 pages, plain Te
Suppression of Bremsstrahlung at Non-Zero Temperature
The first-order bremsstrahlung emission spectrum is
at zero temperature. If the radiation is emitted into a region that contains a
thermal distribution of photons, then the rate is increased by a factor
where is the Bose-Einstein function. The stimulated
emission changes the spectrum to for . If this were correct, an infinite amount of energy would be radiated in the
low frequency modes. This unphysical result indicates a breakdown of
perturbation theory. The paper computes the bremsstrahlung rate to all orders
of perturbation theory, neglecting the recoil of the charged particle. When the
perturbation series is summed, it has a different low-energy behavior. For
, the spectrum is independent of and has a value
proportional to .Comment: 16 pages (plain TeX), figures available on reques
Behavior of logarithmic branch cuts in the self-energy of gluons at finite temperature
We give a simple argument for the cancellation of the log(-k^2) terms (k is
the gluon momentum) between the zero-temperature and the temperature-dependent
parts of the thermal self-energy.Comment: 4 page
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