Equation of state and Beginning of Thermalization After Preheating

By D. Podolsky, Gary N. Felder, Lev Kofman, Marco Peloso. 2005

211 citations recorded by the source corpus.

We study the out-of-equilibrium nonlinear dynamics of fields after post-inflationary preheating. During preheating, the energy in the homogeneous inflaton is exponentially rapidly transfered into highly occupied out-of-equilibrium inhomogeneous modes, which subsequently evolve towards equilibrium. The infrared modes excited during preheating evolve towards a saturated distribution long before thermalization completes. We compute the equation of state during and immediately after preheating. It rapidly evolves towards radiation domination long before the actual thermal equilibrium is established. The exact time of this transition is a nonmonotonic function of the coupling between the inflaton and the decay products, and it varies only very weakly (around ${10}^{\ensuremath{-}35}$ s) as this coupling changes over several orders of magnitude. This result is applied to refine the relation between the number of e-foldings $N$ and the physical wavelength of perturbations generated during inflation. We also discuss the implications for the theory of modulated perturbations from preheating. We finally argue that many questions of the thermal history of the universe should be addressed in terms of prethermalization, illustrating this point with a calculation of perturbative production of gravitinos immediately after chaotic inflation. We also highlight the effects of three-legs inflaton interactions on the dynamics of preheating and thermalization in an expanding universe.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/eea3e355e14795cdf49a78a658ba9e5f9d2a671e

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Citations in the corpus

Gauge-preheating and the end of axion inflation (2015, background): “Our current work addresses a specific problem; given that high-scale inflation requires highly constrained couplings, can the Universe undergo a preheating phase (either tachyonic or resonant) following axion inflation? Numerical investigations of reheating in canonical [43– 55] or non-canonical [56”
Inflation after WMAP3: confronting the slow-roll and exact power spectra with CMB data (2006, methodology): “ogically add a friction term Γφ˙ in the Klein-Gordon equation which now reads [19] φ¨+3Hφ˙ +Γφ˙ + dV(φ) dφ = 0. (16) In fact, this description cannot account for the complexity of the reheating stage [20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30]. But for our purpose, the above treatment will be suﬃci”
Gravity waves from tachyonic preheating after hybrid inflation (2008, background): “During preheating, the equation of state w usually jumps rapidly to a value close to 1/3 [25].”
Reheating predictions in single field inflation (2015, background): “In cases like the ones described in [44] (see also [28]), wre may therefore be rightfully treated as a constant throughout the entire reheating era.”
Observable non-gaussianity from gauge field production in slow roll inflation, and a challenging connection with magnetogenesis (2012, background): “This equation actually receives corrections at second order; however, these corrections are (1) subdominant at the end of inflation, and (2) become even smaller (by several orders of magnitude) during reheating, when the energy in the gauge field decreases faster than the one of the dominating plasm”
Gauge Field Production in Axion Inflation: Consequences for Monodromy, non-Gaussianity in the CMB, and Gravitational Waves at Interferometers (2011, background): “One may therefore expect that the equation of state of the universe will have an intermediate value between that of radiation and matter [57].”