Kinetic theory for particle production

Triginer, Josep; Zimdahl, Winfried; Pavón, Diego

doi:10.1088/0264-9381/13/3/008

Cited by 41 publications

(73 citation statements)

References 22 publications

(56 reference statements)

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“…The first attempt to incorporate gravitational particle production was discussed long ago by Triginer, Zimdahl and Pavón [28]. Following these authors we starting by writing the modified Boltzmann equation in the form:…”

Section: A the Kinetic Non-collisional Termmentioning

confidence: 99%

Gravitationally induced particle production: Thermodynamics and kinetic theory

2014

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A relativistic kinetic description for the irreversible thermodynamic process of gravitationally induced particle production is proposed in the context of an expanding Friedmann-Robertson-Walker (FRW) geometry. We show that the covariant thermodynamic treatment referred to as "adiabatic" particle production provoked by the cosmic time-varying gravitational field has a consistent kinetic counterpart. The variation of the distribution function is associated to a non-collisional kinetic term of quantum-gravitational origin which is proportional to the ratio Γ/H, where Γ is the gravitational particle production rate and H is the Hubble parameter. For Γ << H the process is negligible and as should be expected it also vanishes (regardless of the value of Γ) in the absence of gravitation. The resulting non-equilibrium distribution function has the same functional form of equilibrium with the evolution laws corrected by the particle production process. The macroscopic temperature evolution law is also kinetically derived for massive and massless particles. The present approach points to the possibility of an exact (semi-classical) quantum-gravitational kinetic treatment by incorporating back-reaction effects in the cosmic background.PACS numbers: 98.80.-k, 95.36.+x

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Section: A the Kinetic Non-collisional Termmentioning

confidence: 99%

Gravitationally induced particle production: Thermodynamics and kinetic theory

2014

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“…Particle production within the framework of kinetic theory can be incorporated as a viscous pressure. It has been shown that the inclusion of particle production, in a general relativistic background, leads to a kinetic equation of the form [54] …”

Section: Solutions To the Boltzmann Equation And Foam-modified Thementioning

confidence: 99%

Implications of a stochastic microscopic Finsler cosmology

et al. 2012

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Within the context of supersymmetric space-time (D-particle) foam in string/brane-theory, we discuss a Finsler-induced Cosmology and its implications for (thermal) Dark Matter abundances. This constitutes a truly microscopic model of dynamical space-time, where Finsler geometries arise naturally. The D-particle foam model involves point-like brane defects (D-particles), which provide the topologically non-trivial foamy structures of space-time. The D-particles can capture and emit stringy matter and this leads to a recoil of D-particles. It is indicated how one effect of such a recoil of D-particles is a back-reaction on the space-time metric of Finsler type which is stochastic. We show that such a type of stochastic space-time foam can lead to acceptable cosmologies at late epochs of the Universe, due to the non-trivial properties of the supersymmetric (BPS like) D-particle defects, which are such so as not to affect significantly the Hubble expansion. The restrictions placed on the free parameters of the Finsler type metric are obtained from solving the Boltzmann equation in this background for relic abundances of a Lightest Supersymmetric Particle (LSP) dark matter candidate. It is demonstrated that the D-foam acts as a source for particle production in the Boltzmann equation, thereby leading to enhanced thermal LSP relic abundances relative to those in the Standard ΛCDM Cosmology. For D-particle masses of order TeV, such effects may be relevant for dark matter searches at colliders. The latter constraints complement those coming from high energy gamma-ray astronomy on the induced vacuum refractive index that D-foam models entail. We also comment briefly on the production mechanisms of such TeV-mass stringy defects at colliders, which, in view of the current LHC experimental searches, will impose further constraints on their couplings.

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“…In a similar manner to particle creation cases [16] in imperfect fluids [17,18], the highly nontrivial time-dependence of the mode p H and the transfer of energy between regions, due to the defrosting of this mode across the boundary p H , gives rise to pressure corrections in the fluid energy conservation law. The defrosting of the modes results in a time-dependent "particle number" for regions near p H .…”

Section: Analytical Expression For T µνmentioning

confidence: 92%

“…The defrosting of the modes results in a time-dependent "particle number" for regions near p H . From kinetic theory we know that this "particle creation", (the defrosting of the modes), gives rise to effective viscous pressure modifications [17,18]. The term Π i denotes the effective viscous pressure modification to the "bare" pressure, p i .…”

Section: Analytical Expression For T µνmentioning

confidence: 99%

Equation of state of the trans-Planckian dark energy and the coincidence problem

Bastero-Gil

Mersini

2003

Phys. Rev. D

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Observational evidence suggests that our universe is presently dominated by a dark energy component and undergoing accelerated expansion. We recently introduced a model, motivated by string theory for short-distance physics, for explaining dark energy without appealing to any fine-tuning. The idea of the transplanckian dark energy (TDE) was based on the freeze-out mechanism of the ultralow frequency modes, ω(k) of very short distances, by the expansion of the background universe, ω(k) ≤ H. In this paper we address the issue of the stress-energy tensor for the nonlinear short-distance physics and explain the need to modify Einstein equations in this regime. From the modified Einstein equations we then derive the equation of state for the TDE model, which has the distinctive feature of being continually time-dependent. The explanation of the coincidence puzzle relies entirely on the intrinsic time-evolution of the TDE equation of state.

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Kinetic theory for particle production

Cited by 41 publications

References 22 publications

Gravitationally induced particle production: Thermodynamics and kinetic theory

Gravitationally induced particle production: Thermodynamics and kinetic theory

Implications of a stochastic microscopic Finsler cosmology

Equation of state of the trans-Planckian dark energy and the coincidence problem

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