Accounting for the time evolution of the equation of state parameter during reheating

Saha, Pankaj; Anand, Sampurn; Sriramkumar, L.

doi:10.1103/physrevd.102.103511

Cited by 30 publications

(30 citation statements)

References 70 publications

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“…In this section we enlist the calculations of N reh and T reh by modeling the reheating epoch to be described with a constant equation of state w reh . Note that the equation of state w(t) ≡ p/ρ, in general, is a time dependent parameter determined by the particle physics details of the reheating process [63][64][65][66]. In our approach following Ref.…”

Section: Reheatingmentioning

confidence: 99%

Reheating in Models with Non-minimal Coupling in metric and Palatini formalisms

Cheong,

Lee,

Park

2021

Preprint

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We study reheating of inflationary models with general non-minimal coupling K(φ)R with K(φ) ∼ V (φ) where R is the Ricci scalar and V is the inflaton potential. In particular, when we take the monomial potential K(φ) ∝ φ m with m ∈ Z + , we provide general analytic expressions for cosmological observables. We consider a wide range of nonminimal coupling ξ ∈ [0, ∞) in metric and Palatini formalisms and derive the predictions for cosmological observables and the reheating temperature taking a general equation of state parameter w reh .

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Section: Reheatingmentioning

confidence: 99%

Reheating in Models with Non-minimal Coupling in metric and Palatini formalisms

Cheong,

Lee,

Park

2021

Preprint

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“…There are models where the inflaton ends up oscillating in a steep potential, V (φ) ∝ φ p with p > 4 [5,6,66]. The stiff equation of state, however, hardly lasts longer than a few e-folds [67][68][69][70].…”

Section: Steep Oscillatory Potentialmentioning

confidence: 99%

Kination cosmology from scalar fields and gravitational-wave signatures

Gouttenoire¹,

Servant²,

Simakachorn³

2021

Preprint

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Kination denotes an era in the cosmological history corresponding to an equation of state ω = +1 such that the total energy density of the universe redshifts as the sixth inverse power of the scale factor. This arises if the universe is dominated by the kinetic energy of a scalar field. It has often been motivated in the literature as an era following inflation, taking place before the radiation era. In this paper, we review instead the possibility that kination is disconnected from primordial inflation and occurs much later, inside the Standard Model radiation era. We study the implications on all main sources of primordial gravitational waves. We show how this leads to very distinctive peaked spectra in the stochastic background of long-lasting cosmological sources of gravitational waves, namely the irreducible gravitational waves from inflation, and gravitational waves from cosmic strings, both local and global, with promising observational prospects. We present model-independent signatures and detectability predictions at LIGO, LISA, ET, CE, BBO, as a function of the energy scale and duration of the kination era. We then argue that such intermediate kination era is in fact symptomatic in a large class of axion models. We analyse in details the scalar field dynamics, the working conditions and constraints in the underlying models. We present the gravitational-wave predictions as a function of particle physics parameters. We derive the general relation between the gravitational-wave signal and the axion dark matter abundance as well as the baryon asymmetry. We investigate the predictions for the special case of the QCD axion. The key message is that gravitational-waves of primordial origin represent an alternative experimental probe of axion models.

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“…+ ln a eq a 0 (44) 9 By considering only particles from the standard model we have gre = 106.75 [37]. 10 Detailed numerical modeling usually indicates a monotonic behavior for the reheating equation of state [38][39][40]. 11 Note that we are ignoring the dark energy era domain since it is only relevant very close to the present day.…”

Section: End Of Inflation and Reheatingmentioning

confidence: 99%

Higher-order extension of Starobinsky inflation: initial conditions, slow-roll regime, and reheating phase

Rodrigues-da-Silva,

Bezerra-Sobrinho,

Medeiros

2021

Preprint

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The most current observational data corroborate the Starobinsky model as one of the strongest candidates in the description of an inflationary regime. Motivated by such success, extensions of the Starobinsky model have been increasingly recurrent in the literature. The theoretical justification for this is well grounded: higher-order gravities arise in high-energy physics in the search for the ultraviolet completeness of general relativity. In this paper, we propose to investigate the inflation due to the extension of the Starobinsky model characterized by the inclusion of the R 3 term. We make a complete analysis of the potential and phase space of the model, where we observe the existence of three regions with distinct dynamics for the scalar field. We can establish restrictive limits for the number of e-folds through a study of the reheating and by considering the usual couplings of the standard matter fields and gravity. Thereby, we duly confront our model with the observational data from Planck, BICEP3/Keck, and BAO. Finally, we discuss how the inclusion of the cubic term restricts the initial conditions necessary for the occurrence of a physical inflation.

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Accounting for the time evolution of the equation of state parameter during reheating

Cited by 30 publications

References 70 publications

Reheating in Models with Non-minimal Coupling in metric and Palatini formalisms

Reheating in Models with Non-minimal Coupling in metric and Palatini formalisms

Kination cosmology from scalar fields and gravitational-wave signatures

Higher-order extension of Starobinsky inflation: initial conditions, slow-roll regime, and reheating phase

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