Warm Gauge-Flation with General Dissipative Coefficient

2016 ◽  
Vol 55 (7) ◽  
pp. 3260-3273 ◽  
Author(s):  
M. Sharif ◽  
Rabia Saleem ◽  
Sidra Mohsaneen
Keyword(s):  
Dissipative Coefficient

scholarly journals Analytical Approximation of the Dissipative Standard Map

1999 ◽  
Vol 172 ◽  
pp. 451-452 ◽  
Author(s):  
Alessandra Celletti ◽  
Gabriella Della Penna ◽  
Claude Froeschlé
Keyword(s):  
Approximate Solutions ◽  
Analytical Approximation ◽  
Real Parameter ◽  
Dissipative Systems ◽  
Standard Map ◽  
Dissipative Coefficient ◽  
Standard Mapping ◽  
Integrable Mapping

We investigate the dynamics of a dissipative standard mapping defined by the equationswhere y ∈ R, x ∈ T and ε is a real parameter, we refer to 0 < α < 1 as the “dissipative parameter” and to ψ as the “dissipative coefficient” (ε = α = 0 provides an integrable mapping). Notice that the dynamics is contractive, since the jacobian of the above mapping equals to 1 − α. In particular, we want to compare (see Celletti et al., 1997) the solutions associated to the conservative map (i.e., α = 0) with that related to (1) (α ≠ 0). For simplicity, we consider the case when α = ε2 and construct explicit approximate solutions to the conservative and dissipative systems, using a suitable parametrization like in (Celletti and Chierchia, 1988).

Reconstruction of warm Chaplygin gas inflationary models

2020 ◽  
Vol 35 (32) ◽  
pp. 2050268
Author(s):  
Abdul Jawad ◽  
Shamaila Rani ◽  
Kazuharu Bamba ◽  
Nadeem Azhar
Keyword(s):  
Spectral Index ◽  
Effective Potential ◽  
Chaplygin Gas ◽  
Index Formula ◽  
Curvature Perturbation ◽  
Warm Inflation ◽  
Scalar Spectral Index ◽  
Dissipative Coefficient ◽  
Inflationary Parameters ◽  
Friedmann Robertson Walker

By assuming the specific Chaplygin gas model, we study the reconstruction of warm inflation model with the help of tensor-to-scalar ratio [Formula: see text] and scalar spectral index [Formula: see text]. In this regard, we take flat Friedmann–Robertson–Walker (FRW) metric and discuss the general forms of dissipative coefficient [Formula: see text] as well as effective potential [Formula: see text] for two dissipative regimes i.e., the weak and strong. We use inflationary parameters such as slow-roll parameters, power spectrum of the curvature perturbation, tensor spectrum, spectral index, scalar-to-tensor ratio and Hubble parameter to find the generalized form of dissipative coefficient and effective potential. We discuss the results of dissipative coefficient and reconstructed potential in detail for the specific choice of tensor-to-scalar ratio [Formula: see text] and scalar spectral index [Formula: see text].

scholarly journals Pre-inflation dynamical behavior of warm inflation in loop quantum cosmology

2020 ◽  
Vol 35 (35) ◽  
pp. 2050293
Author(s):  
Kui Xiao ◽  
Sheng-Qin Wang
Keyword(s):  
Quantum Cosmology ◽  
Initial Conditions ◽  
Dynamical Behavior ◽  
Loop Quantum Cosmology ◽  
Warm Inflation ◽  
Dynamical Behaviors ◽  
Slow Roll ◽  
Dissipative Coefficient ◽  
Slow Roll Inflation ◽  
Three Phases

Considering a constant dissipative coefficient [Formula: see text], the pre-inflation dynamical behaviors of warm inflation in the loop quantum cosmology scenario are discussed. We consider three sets of initial conditions. The evolution of the background can always be divided into three phases, namely super-inflation, damping, and slow-roll inflation phases, with the duration of each phase depending on the initial conditions. As an example, we compare the background evolution between [Formula: see text] and [Formula: see text] under special initial conditions and find that there is no slow-roll inflation phase for [Formula: see text] while the number of e-folds is about 60.209 for [Formula: see text].

scholarly journals ASPECTS OF WARM-FLAT DIRECTIONS

2010 ◽  
Vol 25 (22) ◽  
pp. 4221-4237 ◽  
Author(s):  
TOMOHIRO MATSUDA
Keyword(s):  
Thermal Equilibrium ◽  
Strong Interactions ◽  
Cosmological Perturbations ◽  
Inflaton Field ◽  
Warm Inflation ◽  
Qualitative And Quantitative ◽  
Slow Roll ◽  
Dissipative Coefficient ◽  
Inflation Scenario

Considering the mechanism of dissipative slow-roll that has been used in warm inflation scenario, we show that dissipation may alter usual cosmological scenarios associated with SUSY-flat directions. We mainly consider SUSY-flat directions that have strong interactions with nonflat directions and may cause strong dissipation both in thermal and nonthermal backgrounds. An example is the Affleck–Dine mechanism in which dissipation may create significant (both qualitative and quantitative) discrepancies between the conventional scenario and the dissipative one. We also discuss several mechanisms of generating curvature perturbations in which the dissipative field, which is distinguished from the inflaton field, can be used as the source of cosmological perturbations. Considering the Morikawa–Sasaki dissipative coefficient, the damping caused by the dissipation may be significant for many MSSM flat directions even if the dissipation is far from thermal equilibrium.

Warm logamediate inflation in Starobinsky inflationary model

2018 ◽  
Vol 27 (02) ◽  
pp. 1750191
Author(s):  
M. Sharif ◽  
Iqra Nawazish
Keyword(s):  
Scalar Potential ◽  
Power Spectra ◽  
Graphical Analysis ◽  
Strong Interactions ◽  
Inflationary Model ◽  
Tensor Power ◽  
Warm Inflation ◽  
Dissipative Effects ◽  
Dissipative Coefficient ◽  
Weak Regime

This paper investigates the dynamics of warm logamediate inflation for flat isotropic and homogeneous universe in Einstein frame representation of [Formula: see text] gravity. In this scenario, we study dissipative effects for weak and strong interactions of inflaton field via constant and generalized dissipative coefficient. In both interacting regimes, we find inflaton solution corresponding to scalar potential and radiation density of dissipating inflaton. Under slow-roll approximation, we formulate scalar and tensor power spectra, their spectral indices and tensor–scalar ratio for Starobinsky inflationary model and construct graphical analysis of these observational parameters. It is concluded that this model remains compatible with Planck 2015 constraints in weak and strong regimes for constant dissipative coefficient. For generalized dissipative coefficient, the inflationary model yields consistent results for [Formula: see text] and [Formula: see text] in strong regime while condition of warm inflation is violated for [Formula: see text] in weak regime.

scholarly journals General dissipative coefficient in warm intermediate inflation in Loop Quantum Cosmology in light of Planck and BICEP2

2014 ◽  
Vol 23 (10) ◽  
pp. 1450080 ◽  
Author(s):  
Ramón Herrera ◽  
Marco Olivares ◽  
Nelson Videla
Keyword(s):  
Quantum Cosmology ◽  
Loop Quantum Cosmology ◽  
Inflationary Model ◽  
Astronomical Observations ◽  
Hubble Rate ◽  
Slow Roll ◽  
Dissipative Coefficient ◽  
Perturbation Equations

In this paper, we study a warm intermediate inflationary model with a general form for the dissipative coefficient Γ(T, ϕ) = CϕTm/ϕm-1 in the context of Loop Quantum Cosmology (LQC). We examine this model in the weak and strong dissipative regimes. In general, we discuss in great detail the characteristics of this model in the slow-roll approximation. Also, we assume that the modifications to perturbation equations result exclusively from Hubble rate. In this approach, we use recent astronomical observations from Planck and BICEP2 experiments to restrict the parameters in our model.

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