Attractor inflationary solutions in braneworld scenario

2020 ◽  
pp. 2050117
Author(s):  
Saba Qummer ◽  
Abdul Jawad ◽  
M. Younas
Keyword(s):  
Cosmological Parameters ◽  
Energy Condition ◽  
High Energy ◽  
Chaplygin Gas ◽  
Index Formula ◽  
Generalized Chaplygin Gas ◽  
Planck Data ◽  
Strongly Agree ◽  
Generalized Cosmic Chaplygin Gas ◽  
Inflationary Parameters

This paper is devoted to discuss the attractor solutions of inflationary Chaplygin gas models such as generalized Chaplygin gas, modified Chaplygin gas and generalized cosmic Chaplygin gas in the framework of Randall–Sundrum type II braneworld scenario. We investigate the inflationary parameters like scalar spectral index [Formula: see text], tensor to scalar ratio [Formula: see text], and the running of scalar index [Formula: see text] as a function of e-folding numbers [Formula: see text] in the presence of attractor: [Formula: see text]. We evaluate and reformulate these parameters under high energy condition. In this inflationary scenario, we develop [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] planes. We also found that these cosmological parameters and perturbation strongly agree with the recent Planck data 2018 for considered Chaplygin gas models instead of [Formula: see text] in case of generalized cosmic Chaplygin gas.

Power-law plateau and inverse symmetric inflation

2018 ◽  
Vol 27 (08) ◽  
pp. 1850087 ◽  
Author(s):  
Abdul Jawad ◽  
Shahid Chaudhary
Keyword(s):  
Scalar Field ◽  
Power Spectrum ◽  
Spectral Index ◽  
Power Law ◽  
Field Model ◽  
Chaplygin Gas ◽  
Generalized Chaplygin Gas ◽  
Planck Data ◽  
Inflationary Parameters ◽  
Ratio Versus

Warm generalized Chaplygin gas inflation is being studied by assuming power-law plateau and inverse symmetric potentials with standard scalar field model. We consider strong dissipative regime with generalized dissipative coefficient and extract the various inflationary parameters such as scalar power spectrum, spectral index, tensor-to-scalar ratio and running of spectral index. It is found that both inflationary potentials favor the strong dissipative regime. Also, we construct the [Formula: see text]–[Formula: see text] (running of spectral index versus spectral index) and [Formula: see text]–[Formula: see text] (tensor-to-scalar ratio versus spectral index) planes and found that the trajectories of these planes favor WMAP 7 [Formula: see text] WMAP 9 and latest Planck data.

scholarly journals On Chaplygin Gas Braneworld Inflation with Monomial Potential

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
A. Safsafi ◽  
I. Khay ◽  
F. Salamate ◽  
H. Chakir ◽  
M. Bennai
Keyword(s):  
High Energy ◽  
Chaplygin Gas ◽  
Type Ii ◽  
Energy Limit ◽  
Generalized Chaplygin Gas ◽  
Planck Data ◽  
Central Value ◽  
Braneworld Model ◽  
Perturbation Parameters ◽  
Braneworld Inflation

We study the Chaplygin gas model as a candidate for inflation in the framework of the Randall-Sundrum type II braneworld model. We consider the original and generalized Chaplygin gas model in the presence of monomial potential. The inflationary spectrum perturbation parameters are reformulated and evaluated in the high-energy limit and we found that they depend on several parameters. We also showed that these perturbation parameters are widely compatible with the recent Planck data for a particular choice of the parameters space of the model. A suitable observational central value of ns≃0.965 is also obtained in the case of original and generalized Chaplygin gas.

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].

Interacting closed string tachyon with generalized cosmic Chaplygin gas

2014 ◽  
Vol 11 (08) ◽  
pp. 1450065 ◽  
Author(s):  
Ali R. Amani ◽  
B. Pourhassan
Keyword(s):  
Fixed Point ◽  
Stability Analysis ◽  
Cosmological Model ◽  
Cosmological Parameters ◽  
Chaplygin Gas ◽  
Closed String ◽  
Cosmological Model Of Universe ◽  
Generalized Cosmic Chaplygin Gas

In this paper, we consider interacting closed string tachyon with generalized cosmic Chaplygin gas as a cosmological model of Universe. We obtained cosmological parameters and discuss about fixed point for stability analysis. We find appropriate conditions where the theory is stable.

scholarly journals Interacting models of generalized Chaplygin gas and modified Chaplygin gas with barotropic fluid

2019 ◽  
Vol 34 (09) ◽  
pp. 1950064 ◽  
Author(s):  
Promila Biswas ◽  
Ritabrata Biswas
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Cosmological Parameters ◽  
Chaplygin Gas ◽  
Cosmic Acceleration ◽  
Late Time ◽  
Modified Chaplygin Gas ◽  
Interaction Coefficients ◽  
Generalized Chaplygin Gas ◽  
Barotropic Fluid

In this paper, we consider two different models of our present universe. We choose the models which consist of different sets of two separate fluids. The first one of each set tries to justify the late time acceleration and the second one is barotropic fluid. The former model considers our present time universe to be homogeneously filled up by Generalized Chaplygin Gas which is interacting with barotropic fluid. On the other hand, the latter model considers that the cosmic acceleration is generated by Modified Chaplygin Gas which is interacting with matter depicted by barotropic equation of state (EoS). For both the models, we consider the interaction term to vary proportionally with Hubble’s parameter as well as with the exotic matter/dark energy’s energy density. We find an explicit function form of the energy density of the cosmos which is found to depend on different cosmological parameters like scale factor, dark energy and barotropic fluid’s EoS parameters and other constants, like interacting constants, etc. We draw curves of effective EoS-s, different cosmological parameters like deceleration parameter q, statefinder parameters r and s with respect to the redshift z (for different values of dark energy and barotropic fluid parameters) and study them thoroughly. We compare two models as well as the nature of dependencies on these models’ interaction coefficients. We point out the particular redshift for which the universe may transit from a deceleration to acceleration phase. We tally all these values with different observational data. Here, we also analyze how this value of particular redshift does change for different values of interaction coefficients and different dark energy models.

Linearized stability of cylindrical thin-shell wormholes

2016 ◽  
Vol 94 (2) ◽  
pp. 158-169 ◽  
Author(s):  
M. Sharif ◽  
Saadia Mumtaz
Keyword(s):  
Thin Shell ◽  
Chaplygin Gas ◽  
Energy Conditions ◽  
Energy Tensor ◽  
Generalized Chaplygin Gas ◽  
Linearized Stability ◽  
Unstable Solutions ◽  
Thin Shell Wormholes ◽  
The Stability ◽  
Generalized Cosmic Chaplygin Gas

The objective of this paper is to investigate the stability of cylindrical thin-shell wormholes. We follow the Visser’s cut and paste approach for the construction of thin-shell. The Darmois–Israel formalism is used to determine the stress–energy tensor. The null and weak energy conditions as well as attractive and repulsive characteristics of thin-shell wormholes are analyzed. We find both stable and unstable solutions by taking dark energy, generalized cosmic Chaplygin gas, and modified cosmic Chaplygin gas models as exotic matter at the wormhole throat. Finally, we compare our results with those for modified generalized Chaplygin gas model.

scholarly journals Involvement of Progranulin in Hypothalamic Glucose Sensing and Feeding Regulation

Endocrinology ◽  
2011 ◽  
Vol 152 (12) ◽  
pp. 4672-4682 ◽  
Author(s):  
Hyun-Kyong Kim ◽  
Mi-Seon Shin ◽  
Byung-Soo Youn ◽  
Churl Namkoong ◽  
So Young Gil ◽  
...  
Keyword(s):  
Neuropeptide Y ◽  
Energy Condition ◽  
Physiological Role ◽  
High Energy ◽  
Glucose Sensing ◽  
Energy Conditions ◽  
Related Peptide ◽  
Feeding Regulation ◽  
Nocturnal Feeding ◽  
Hypothalamic Regulation

Progranulin (PGRN) is a secreted glycoprotein with multiple biological functions, including modulation of wound healing and inflammation. Hypothalamic PGRN has been implicated in the development of sexual dimorphism. In the present study, a potential role for PGRN in the hypothalamic regulation of appetite and body weight was investigated. In adult rodents, PGRN was highly expressed in periventricular tanycytes and in hypothalamic neurons, which are known to contain glucose-sensing machinery. Hypothalamic PGRN expression levels were decreased under low-energy conditions (starvation and 2-deoxy-D-glucose administration) but increased under high-energy condition (postprandially). Intracerebrovetricular administration of PGRN significantly suppressed nocturnal feeding as well as hyperphagia induced by 2-deoxyglucose, neuropeptide Y, and Agouti-related peptide. Moreover, the inhibition of hypothalamic PGRN expression or action increased food intake and promoted weight gain, suggesting that endogenous PGRN functions as an appetite suppressor in the hypothalamus. Investigation of the mechanism of action revealed that PGRN diminished orexigenic neuropeptide Y and Agouti-related peptide production but stimulated anorexigenic proopiomelanocortin production, at least in part through the regulation of hypothalamic AMP-activated protein kinase. Notably, PGRN was also expressed in hypothalamic microglia. In diet-induced obese mice, microglial PGRN expression was increased, and the anorectic response to PGRN was blunted. These findings highlight a physiological role for PGRN in hypothalamic glucose-sensing and appetite regulation. Alterations in hypothalamic PGRN production or action may be linked to appetite dysregulation in obesity.

scholarly journals OBSERVATIONAL CONSTRAINTS ON THE GENERALIZED CHAPLYGIN GAS

2009 ◽  
Vol 18 (13) ◽  
pp. 2007-2022 ◽  
Author(s):  
SERGIO DEL CAMPO ◽  
J. R. VILLANUEVA
Keyword(s):  
Dark Energy ◽  
Cosmological Model ◽  
Chaplygin Gas ◽  
Observational Constraints ◽  
Energy Component ◽  
Generalized Chaplygin Gas ◽  
Astronomical Data ◽  
Astronomical Observations ◽  
Dark Energy Component ◽  
Two Parameters

In this paper we study a quintessence cosmological model in which the dark energy component is considered to be the generalized Chaplygin gas and the curvature of the three-geometry is taken into account. Two parameters characterize this sort of fluid: ν and α. We use different astronomical data for restricting these parameters. It is shown that the constraint ν ≲ α agrees well enough with the astronomical observations.

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