Separation of Equilibration Time-Scales in the Gradient Expansion

Abstract

We study thermalization by applying gradient expansion to the Kadanoff-Baym equations of the 2PI effective action to two-loop in a theory with Dirac fermions coupled to scalars. In addition to those chemical potentials which equilibrate in the on-shell limit, we identify modes which are conserved in this approximation, but which relax when off-shell effects are taken into account. This implies that chemical equilibration does not require higher loop contributions to the effective action and is compatible with the gradient expansion. We explicitly calculate the damping time-scales of both, on- and off-shell, chemical equilibration rates. It is shown that off-shell equilibration is suppressed by the thermal width of the particles in the plasma, which explains the separation of on- and off-shell chemical equilibration time-scales.

20 pages, 3 figures, published version

References in corpus (12)

• From Kadanoff-Baym dynamics to off-shell parton transport
• Transport equations for chiral fermions to order \hbar and electroweak baryogenesis: Part II
• MSSM Electroweak Baryogenesis and Flavour Mixing in Transport Equations
• Equilibration in phi^4 theory in 3+1 dimensions
• Kinetic description of fermion flavor mixing and CP-violating sources for baryogenesis
• Range of validity of transport equations
• Yukawa Interactions and Supersymmetric Electroweak Baryogenesis
• Quantum field thermalization in expanding backgrounds
• Isotropization far from equilibrium
• Comparison of Boltzmann Kinetics with Quantum Dynamics for a Chiral Yukawa Model Far From Equilibrium
• The Effect of the Sparticle Mass Spectrum on the Conversion of B-L to B
• Kinetic and Chemical Equilibration in Scalar phi^4 Theory

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• Finite Width in out-of-Equilibrium Propagators and Kinetic Theory
• On the Role of Quasiparticles and thermal Masses in Nonequilibrium Processes in a Plasma
• Relativistic and spectator effects in leptogenesis with heavy sterile neutrinos
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• Perturbative Non-Equilibrium Thermal Field Theory to all Orders in Gradient Expansion
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• Creating the Baryon Asymmetry from Lepto-Bubbles