Reheating predictions in gravity theories with derivative coupling

Dalianis, Ioannis; Koutsoumbas, G.; Ntrekis, Konstantinos; Papantonopoulos, Eleftherios

doi:10.1088/1475-7516/2017/02/027

Cited by 40 publications

(35 citation statements)

References 112 publications

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“…In addition to this, there is a unique nonminimal derivative coupling of the Standard Model Higgs boson to gravity which propagates no more degrees of freedom than General Relativity sourced by a scalar field, and reproduces a successful inflating background within the Standard Model Higgs parameters and, finally, does not suffer from dangerous quantum corrections [51]. The slow-roll conditions have been found [52], and the reheating temperature was obtained [53,54] (see also recent analyses in [55] and [56]). Furthermore, the cosmological perturbations originated at the inflationary stage were studied and the consistency of the results with observational constraints coming from Planck 2013 data were investigated [57].…”

Section: Introductionmentioning

confidence: 78%

Cosmological models in modified gravity theories with extended nonminimal derivative couplings

2017

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We construct gravitational modifications that go beyond Horndeski, namely theories with extended nonminimal derivative couplings, in which the coefficient functions depend not only on the scalar field but also on its kinetic energy. Such theories prove to be ghost-free in a cosmological background. We investigate the early-time cosmology and show that a de Sitter inflationary phase can be realized as a pure result of the novel gravitational couplings. Additionally, we study the latetime evolution, where we obtain an effective dark energy sector which arises from the scalar field and its extended couplings to gravity. We extract various cosmological observables and analyse their behavior at small redshifts for three choices of potentials, namely, for the exponential, the powerlaw, and the Higgs potential. We show that the Universe passes from deceleration to acceleration in the recent cosmological past, while the effective dark-energy equation-of-state parameter tends to the cosmological-constant value at present. Finally, the effective dark energy can be phantom-like, although the scalar field is canonical, which is an advantage of the model.PACS numbers: 04.50. Kd, 95.36.+x

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Section: Introductionmentioning

confidence: 78%

Cosmological models in modified gravity theories with extended nonminimal derivative couplings

2017

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“…In principle the parameter α can also be a slowly varying function of N [38]. In addition the expansion (14), for some inflation models, may involve parameters of the potential [33]. Here we assume that α is a constant and absorb possible complicated behaviors in the arbitrary β(N ) function.…”

Section: 1mentioning

confidence: 99%

“…Also, going at next-to-leading order we could probe ∆N X ∼ 1 changes that could shed light on the pre-BBN cosmic history. For the Starobinsky model the expression (14) reads [33]…”

Section: The Starobinsky R 2 Inflationmentioning

confidence: 99%

“…The fact that the N * is modified by the details of the dark pre-BBN stage [3] motivate us to investigate this small but non-zero residual dependence of the inflationary predictions on the tentative BSM physics. In most of the inflationary models, a precise measurement of the spectral index n s (N * ) and tensor-to-scalar ratio r(N * ) value accounts for an indirect measure of the reheating temperature of the universe [4,5,6,7,8,9,10,11,12,13] and hence one could in principle examine the cosmology of theories beyond the Standard Model of particle physics as well as non-trivial extensions of the Einstein gravity [14]. From the inflation phenomenology point of view, for a given concrete BSM scenario a predictive inflationary model can be spotted on the (n s , r) plane, whereas from the particle physicist point of view, for a given predictable inflationary scenario the precise measurement of the (n s , r) observables is a measurement of the BSM effects on the cosmic evolution.…”

Section: Introductionmentioning

confidence: 99%

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Probing the BSM physics with CMB precision cosmology: an application to supersymmetry

Dalianis

Watanabe

2018

J. High Energ. Phys.

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The cosmic history before the BBN is highly determined by the physics that operates beyond the Standard Model (BSM) of particle physics and it is poorly constrained observationally. Ongoing and future precision measurements of the CMB observables can provide us with significant information about the pre-BBN era and hence possibly test the cosmological predictions of different BSM scenarios. Supersymmetry is a particularly motivated BSM theory and it is often the case that different superymmetry breaking schemes require different cosmic histories with specific reheating temperatures or low entropy production in order to be cosmologically viable. In this paper we quantify the effects of the possible alternative cosmic histories on the n s and r CMB observables assuming a generic non-thermal stage after cosmic inflation. We analyze TeV and especially multi-TeV supersymmetry breaking schemes assuming the neutralino and gravitino dark matter scenarios. We complement our analysis considering the Starobinsky R 2 inflation model to exemplify the improved CMB predictions that a unified description of the early universe cosmic evolution yields. Our analysis underlines the importance of the CMB precision measurements that can be viewed, to some extend, as complementary to the laboratory experimental searches for supersymmetry or other BSM theories.

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“…However, it is not clear from this scenario how reheating occurs or the Universe becomes radiation dominated after the end of inflation. For a non-minimal derivative coupling model, the reheating process after the slow roll and warm slow roll inflation are studied in [41][42][43][44][45][46][47][48], respectively.…”

Section: Introductionmentioning

confidence: 99%

Warm inflation with an oscillatory inflaton in the non-minimal kinetic coupling model

Goodarzi

Sadjadi

2017

Eur. Phys. J. C

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In the cold inflation scenario, the slow roll inflation and reheating via coherent rapid oscillation, are usually considered as two distinct eras. When the slow roll ends, a rapid oscillation phase begins and the inflaton decays to relativistic particles reheating the Universe. In another model dubbed warm inflation, the rapid oscillation phase is suppressed, and we are left with only a slow roll period during which the reheating occurs. Instead, in this paper, we propose a new picture for inflation in which the slow roll era is suppressed and only the rapid oscillation phase exists. Radiation generation during this era is taken into account, so we have warm inflation with an oscillatory inflaton. To provide enough e-folds, we employ the non-minimal derivative coupling model. We study the cosmological perturbations and compute the temperature at the end of warm oscillatory inflation.

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Reheating predictions in gravity theories with derivative coupling

Cited by 40 publications

References 112 publications

Cosmological models in modified gravity theories with extended nonminimal derivative couplings

Cosmological models in modified gravity theories with extended nonminimal derivative couplings

Probing the BSM physics with CMB precision cosmology: an application to supersymmetry

Warm inflation with an oscillatory inflaton in the non-minimal kinetic coupling model

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