scholarly journals Generalized second law of thermodynamics in the presence of interacting tachyonic field and scalar (phantom) field

2010 ◽  
Vol 88 (12) ◽  
pp. 933-938 ◽  
Author(s):  
Surajit Chattopadhyay ◽  
Ujjal Debnath
Keyword(s):  
Scalar Field ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Frw Universe ◽  
Tachyonic Field ◽  
Phantom Field ◽  
Generalized Second Law

In the present work, we consider the tachyonic field, the phantom field, and the scalar field in both interacting and non-interacting situations and investigate the validity of the generalized second law of thermodynamics in a flat FRW universe. We find that in all cases, except for the phantom field dominated universe, the derivative of the entropy remains at negative level and increases with the decrease in redshift.

A unified picture of cosmological entropy on apparent horizon in F(R, G) gravity

2017 ◽  
Vol 32 (33) ◽  
pp. 1750182 ◽  
Author(s):  
Ali İhsan Keskin ◽  
Irfan Acikgoz
Keyword(s):  
Apparent Horizon ◽  
Second Law Of Thermodynamics ◽  
Hawking Temperature ◽  
Second Law ◽  
Field Equations ◽  
Frw Universe ◽  
Generalized Second Law ◽  
History Of ◽  
The Universe ◽  
Friedmann Robertson Walker

In this study, the validity of the generalized second law of thermodynamics (GSLT) has been investigated in F(R, G) gravity. We consider that the boundary of the universe is surrounded by an apparent horizon in the spatially flat Friedmann–Robertson–Walker (FRW) universe, and we take into account the Hawking temperature on the horizons. The unified solutions of the field equations corresponding to gravity theory have been applied to the validity of the GSLT frame, and in this way, both the solutions have been verified and all the expansion history of the universe has been shown in a unified picture.

scholarly journals Thermodynamic Implications of Multiquintessence Scenario

Entropy ◽  
2019 ◽  
Vol 21 (9) ◽  
pp. 851 ◽  
Author(s):  
Abdul Jawad ◽  
Zoya Khan ◽  
Shamaila Rani ◽  
Kazuharu Bamba
Keyword(s):  
Hubble Parameter ◽  
Thermal Equilibrium ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Frw Universe ◽  
Equilibrium Conditions ◽  
Potential Models ◽  
First Order ◽  
Generalized Second Law ◽  
Friedmann Robertson Walker

In this paper, we discuss the validity of the generalized second law of thermodynamics in the presence of a multi-component scalar field ( ϕ ) in a spatially flat Friedmann-Robertson-Walker (FRW) universe. We describe the first-order formalism by defining the Hubble parameter as H = - W ( ϕ i ) . By using three super-potential models of the Hubble parameter, we analyze the validity of the generalized law and thermal equilibrium conditions in the presence of the logarithmically-corrected, Bekenstein-Hawking, Sharma-Mittal and R e ´ n y i entropies. It is noticed that the generalized law and thermal equilibrium conditions hold for some cases.

scholarly journals Qualitative aspects of Rastall gravity with barotropic fluid

2021 ◽  
Author(s):  
Ashutosh Singh ◽  
Rakesh Raushan ◽  
R. Chaubey
Keyword(s):  
Dynamical System ◽  
Equation Of State ◽  
System Approach ◽  
Apparent Horizon ◽  
Dynamical Evolution ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Frw Universe ◽  
Barotropic Fluid ◽  
Generalized Second Law

We investigate the dynamical evolution of homogeneous and isotropic flat-FRW universe filled with a barotropic fluid satisfying linear equation of state in Rastall gravity. Using dynamical system approach, we find the fixed points of the system and study their stability. We further explore the thermodynamic aspects at the apparent horizon by investigating the validity of generalized second law of thermodynamics with equilibrium description.

scholarly journals GENERALIZED SECOND LAW OF THERMODYNAMICS IN THE PRESENCE OF INTERACTING DBI-ESSENCE AND OTHER DARK ENERGIES

2010 ◽  
Vol 25 (30) ◽  
pp. 5557-5566 ◽  
Author(s):  
SURAJIT CHATTOPADHYAY ◽  
UJJAL DEBNATH
Keyword(s):  
Dark Energy ◽  
Event Horizon ◽  
Second Law Of Thermodynamics ◽  
Chaplygin Gas ◽  
Second Law ◽  
Modified Chaplygin Gas ◽  
Tachyonic Field ◽  
New Agegraphic Dark Energy ◽  
Generalized Second Law ◽  
Increasing Function

In the present work we investigated the validity of the generalized second law (GSL) of thermodynamics in the presence of interaction between DBI-essence and other four candidates of dark energy, namely the modified Chaplygin gas, hessence, tachyonic field and new agegraphic dark energy. It has been observed that the GSL breaks down in the presence of the interactions. However, the event horizon remains to be an increasing function of time.

scholarly journals Thawing and freezing quintessence models: a thermodynamic consideration

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Tanima Duary ◽  
Ananda Dasgupta ◽  
Narayan Banerjee
Keyword(s):  
Scalar Field ◽  
Field Model ◽  
Second Law Of Thermodynamics ◽  
Matter Content ◽  
Second Law ◽  
Correct Description ◽  
Thermodynamic Consideration ◽  
Scalar Field Model ◽  
The Past ◽  
Generalized Second Law

Abstract Thawing and freezing quintessence models are compared thermodynamically. Both of them are found to disobey the generalized second law of thermodynamics. However, for freezing models, there is still a scope as this breakdown occurs in the past, deep inside the radiation dominated era, when a standard scalar field model with a pressureless matter is not a correct description of the matter content. The thawing model has a pathological breakdown in terms of thermodynamics in a finite future.

Thermodynamics in loop quantum cosmology with non-canonical scalar field model

2019 ◽  
Vol 16 (06) ◽  
pp. 1950081
Author(s):  
Ayesha Iqbal ◽  
Abdul Jawad
Keyword(s):  
Scalar Field ◽  
Equation Of State ◽  
Equilibrium Condition ◽  
Field Model ◽  
State Parameter ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Generalized Second Law ◽  
Equation Of State Parameter ◽  
The Universe

The cosmological scenario is built up within the framework of scalar field model possessing a noncanonical kinetic term in loop quantum gravity. The noncanonical scalar field is permitted to interact with dark matter field by assuming a specific form of coupling term. The equation of state parameter is set to be constant as well as variable (Chevallier–Polarski–Linder parametrization) and evaluated the behavior of universe through deceleration parameter and weak energy condition. These parameters favor the accelerated expansion of the universe for three values of equation of state parameter in both cases allowed by observational data. The squared speed of sound leads to the stability of the underlying models in both forms of equation of state parameter. Moreover, the validity of generalized second law of thermodynamics is analyzed by using first law of thermodynamics and assume the universe to be enclosed by apparent horizon. The Bekenstein, logarithmic and power-law entropy is being considered as entropy of horizon. The thermodynamic equilibrium condition is also discussed for all three cases of entropies. The generalized second law of thermodynamics and thermal equilibrium condition is satisfied for all the three types of entropies.

scholarly journals The generalized second law of thermodynamics for interacting f(R) gravity

2014 ◽  
Vol 23 (08) ◽  
pp. 1450071 ◽  
Author(s):  
Ramón Herrera ◽  
Nelson Videla
Keyword(s):  
Apparent Horizon ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Effective Equation ◽  
Frw Universe ◽  
Total Energy Density ◽  
Generalized Second Law ◽  
Interaction Term ◽  
The Universe ◽  
Gravitational Thermodynamics

In this paper, we examine the validity of the generalized second law (GSL) of gravitational thermodynamics in the context of interacting f(R) gravity. We take into account that the boundary of the universe to be confined by the dynamical apparent horizon in a flat FRW universe. We study the effective equation of state, deceleration parameter and GSL in this interaction-framework. We find that the evolution of the total entropy increases through the interaction term. As an example, we consider a f(R) gravity with a power-law dependence on the curvature R. Here, we find exact solutions for a model in which the interaction term is related to the total energy density of matter.

Cosmological consequences of modified Friedmann equations according to holographic equipartition law

2021 ◽  
Vol 36 (10) ◽  
pp. 2150069
Author(s):  
Abdul Jawad ◽  
Sidra Saleem ◽  
Saba Qummer
Keyword(s):  
Equation Of State ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Om Diagnostic ◽  
Generalized Second Law ◽  
Friedmann Equations ◽  
Equation Of State Parameter ◽  
Equipartition Law

We examine thermodynamically an extra driving term for the flat universe by applying Sharma Mittal entropy to Padmanabhan’s holographic equipartition law. Deviations from the Bekenstein–Hawking entropy by using this law, we generate an extra driving in the acceleration equation. By using the constant and parametrized equation of state parameter, we investigate the different cosmological parameters like deceleration parameter, squared speed of sound, Om-diagnostic and statefinder parameter through graphical approach. We observe compatible results with current observational data in both models. Generalized second law of thermodynamics also remains valid in both cases.

Sign in / Sign up

Export Citation Format

Share Document