CMB and reheating constraints to<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>α</mml:mi></mml:math>-attractor inflationary models

Eshaghi, Mehdi; Zarei, Moslem; Riazi, N.; Kiasatpour, Ahmad

doi:10.1103/physrevd.93.123517

Cited by 60 publications

(38 citation statements)

References 75 publications

(204 reference statements)

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“…We will follow the formalism developed in our recent papers [51,52] generalizing the works in [53,54] for decaying inflaton. For recent studies on CMB constraints on reheating phase see [55][56][57][58][59][59][60][61][62][63]. In our following analysis, we will assume that the decay of total energy density ρ t whose initial value will be identified with the value obtained after the end of preheating is via a phenomenological decay term.…”

Section: Perturbative Reheating and Constraints From Cmbmentioning

confidence: 99%

(P)reheating after minimal plateau inflation and constraints from CMB

Maity

Saha

2019

J. Cosmol. Astropart. Phys.

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In this paper we have investigated the preheating phase for a class of plateau inflationary model considering the four-legs interaction term (1/2)g 2 φ 2 χ 2 between the inflaton (φ) and reheating field (χ). We specifically focus on the effects of our model parameter φ * which controls inflationary dynamics. For φ * < M p , the departure of the inflaton potential from the usual power-law behavior φ n significantly modifies the microscopic behavior of the preheating dynamics. We analyze and compare the efficiency of production, thermalization behavior and the final equation of states of the system for different values of n = 2, 4, 6 considering two different values of φ * . Most importantly as we increase n, or decrease φ * , the preheating occurs very efficiently with the final equation of state to be that of the radiation, w = 1/3. However, for n = 2, the final equation of state turned out to be w 0.2. In the non-perturbative framework complete decay of inflaton could not be achieved with the four-legs interaction for any model under consideration. Therefore, in order to complete the reheating process, we perform the perturbative analysis for the second stage of the reheating phase. With the appropriate initial condition set by the non-perturbative dynamics, we solved a set of homogeneous Boltzmann equations for both the fields supplemented by the constraints coming from the subsequent entropy conservation. In so doing, we calculated the reheating temperature which was otherwise ill-defined right after the end of preheating. The temperature can be uniquely fixed for a given inflaton decay constant and the CMB temperature. We also compare our results with the conventional reheating constraint analysis and discuss the limits on the inflaton decay constant from the field theory perspective.

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Section: Perturbative Reheating and Constraints From Cmbmentioning

confidence: 99%

(P)reheating after minimal plateau inflation and constraints from CMB

Maity

Saha

2019

J. Cosmol. Astropart. Phys.

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“…By solving field equations in the leading approximation in 1/N , one finds [52] ϕ N ≈ 3α 2 log 4N 3α . For α-attractors with a more general class of potentials V = m 2 1 − e…”

Section: Basic Single-disk Modelsmentioning

confidence: 99%

Maximal supersymmetry and B-mode targets

Каллош

Linde

Wrase

et al. 2017

J. High Energ. Phys.

158

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Extending the work of Ferrara and one of the authors [1], we present dynamical cosmological models of α-attractors with plateau potentials for 3α = 1, 2, 3, 4, 5, 6, 7. These models are motivated by geometric properties of maximally supersymmetric theories: Mtheory, superstring theory, and maximal N = 8 supergravity. After a consistent truncation of maximal to minimal supersymmetry in a seven-disk geometry, we perform a two-step procedure: 1) we introduce a superpotential, which stabilizes the moduli of the seven-disk geometry in a supersymmetric minimum, 2) we add a cosmological sector with a nilpotent stabilizer, which breaks supersymmetry spontaneously and leads to a desirable class of cosmological attractor models. These models with n s consistent with observational data, and with tensor-to-scalar ratio r ≈ 10 −2 − 10 −3 , provide natural targets for future B-mode searches. We relate the issue of stability of inflationary trajectories in these models to tessellations of a hyperbolic geometry.

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“…However, there is a gap in our understanding of how inflation ends and ultimately leads to a radiation-dominated, thermal universe before the production of light elements. The poorly constrained post-inflationary equation of state of the universe and the duration before radiation domination influence the interpretation of inflationary observables and the reheating temperature [2][3][4][5][6][7][8][9][10][11]; they affect predictions for baryogenesis and primordial relics [12][13][14].…”

mentioning

confidence: 99%

Equation of State and Duration to Radiation Domination after Inflation

2017

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We calculate the equation of state after inflation and provide an upper bound on the duration before radiation domination by taking the nonlinear dynamics of the fragmented inflaton field into account. A broad class of single-field inflationary models with observationally consistent flattening of the potential at a scale M away from the origin, V (φ) ∝ |φ| 2n near the origin, and where the couplings to other fields are ignored are included in our analysis. We find that the equation of state parameter w → 0 for n = 1 and w → 1/3 (after sufficient time) for n 1. We calculate how the number of e-folds to radiation domination depends on both n and M when M ∼ mPl, whereas when M mPl, we find that the duration to radiation domination is negligible. Our results are explained in terms of a linear instability analysis in an expanding universe, scaling arguments, and are supported by 3+1 dimensional lattice simulations. We show how our work significantly reduces the uncertainty in inflationary observables, even after including couplings to additional light fields.Introduction -Inflationary cosmology provides a consistent framework for calculating the initial conditions responsible for the observed temperature fluctuations in the cosmic microwave background [1]. However, there is a gap in our understanding of how inflation ends and ultimately leads to a radiation-dominated, thermal universe before the production of light elements. The poorly constrained post-inflationary equation of state of the universe and the duration before radiation domination influence the interpretation of inflationary observables and the reheating temperature [2-11]; they affect predictions for baryogenesis and primordial relics [12][13][14].

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CMB and reheating constraints toα-attractor inflationary models

Cited by 60 publications

References 75 publications

(P)reheating after minimal plateau inflation and constraints from CMB

(P)reheating after minimal plateau inflation and constraints from CMB

Maximal supersymmetry and B-mode targets

Equation of State and Duration to Radiation Domination after Inflation

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