Universal thermodynamics in inhomogeneous FLRW-type model: Thermal equilibrium

2019 ◽  
Vol 16 (05) ◽  
pp. 1950074
Author(s):  
Pritikana Bhandari ◽  
Subenoy Chakraborty
Keyword(s):  
Thermal Equilibrium ◽  
Integrability Condition ◽  
Second Law Of Thermodynamics ◽  
Type Model ◽  
Gibbs Equation ◽  
Thermodynamical Equilibrium ◽  
Time Model ◽  
Event Horizons ◽  
Generalized Second Law ◽  
Space Time Model

A study of the universal thermodynamics has been done for the inhomogeneous Friedmann–Lemaitre–Robertson–Walker type (FLRW-type) space-time model. Validity of the generalized second law of thermodynamics has been examined across an arbitrary horizon and integrability condition for the generalized Gibbs equation has been determined. Also, the conditions for thermodynamical equilibrium have been presented in a tabular form. Finally, using unified first law, the corrected Bekenstein entropy has been evaluated for both apparent and event horizons.

scholarly journals Thermodynamics of Ricci-Gauss-Bonnet Dark Energy

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Ayesha Iqbal ◽  
Abdul Jawad
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Cold Dark Matter ◽  
Apparent Horizon ◽  
Second Law Of Thermodynamics ◽  
Frw Universe ◽  
Thermodynamical Equilibrium ◽  
Event Horizons ◽  
Generalized Second Law ◽  
Friedmann Robertson Walker

We investigate the validity of generalized second law of thermodynamics of a physical system comprising newly proposed dark energy model called Ricci-Gauss-Bonnet and cold dark matter enveloped by apparent horizon and event horizon in flat Friedmann-Robertson-Walker (FRW) universe. For this purpose, Bekenstein entropy, Renyi entropy, logarithmic entropy, and power law entropic corrections are used. It is found that this law exhibits the validity on both apparent and event horizons except for the case of logarithmic entropic correction at apparent horizon. Also, we check the thermodynamical equilibrium condition for all cases of entropy and found its vitality in all cases of entropy.

Analysis of cubic gravity through cosmic aspects

2020 ◽  
Vol 17 (09) ◽  
pp. 2050134 ◽  
Author(s):  
Zoya Khan ◽  
Shamaila Rani ◽  
Abdul Jawad ◽  
G. Mustafa
Keyword(s):  
Hubble Parameter ◽  
Thermal Equilibrium ◽  
Equilibrium Condition ◽  
Cosmological Parameters ◽  
Second Law Of Thermodynamics ◽  
Observational Constraints ◽  
Eos Parameter ◽  
Generalized Second Law ◽  
Thermal Equilibrium Condition ◽  
Almost All

In the context of cubic gravity for flat FRW metric we discuss the behavior of cosmological parameters (equation of state (EoS) parameter and square speed of sound) at Hubble horizon with the four different models of Hubble parameter. We observe the validity of generalized second law of thermodynamics (GSLT) and thermal equilibrium condition. It is found that cosmological parameters lie within the observational constraints. Also, GSLT and thermal equilibrium condition holds in almost all cases of Hubble parameter.

scholarly journals A Study of Universal Thermodynamics in Brane World Scenario

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Saugata Mitra ◽  
Subhajit Saha ◽  
Subenoy Chakraborty
Keyword(s):  
Second Law Of Thermodynamics ◽  
Chaplygin Gas ◽  
Brane World ◽  
Second Law ◽  
Modified Chaplygin Gas ◽  
Thermodynamical Equilibrium ◽  
Brane Model ◽  
Generalized Second Law ◽  
Frw Model ◽  
The Universe

A study of Universal thermodynamics is done in the framework of RSII brane model and DGP brane scenario. The Universe is chosen as FRW model bounded by apparent or event horizon. Assuming extended Hawking temperature on the horizon, the unified first law is examined for perfect fluid (with constant equation of state) and Modified Chaplygin Gas model. As a result there is a modification of Bekenstein entropy on the horizons. Further the validity of the generalized second law of thermodynamics and thermodynamical equilibrium are also investigated.

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.

A thermodynamical analysis of the inhomogeneous FLRW type model: Redefined Bekenstein–Hawking system

2017 ◽  
Vol 14 (11) ◽  
pp. 1750159 ◽  
Author(s):  
Sourav Haldar ◽  
Pritikana Bhandari ◽  
Subenoy Chakraborty
Keyword(s):  
Second Law Of Thermodynamics ◽  
Integral Form ◽  
The Other ◽  
Type Model ◽  
First Law Of Thermodynamics ◽  
Generalized Second Law ◽  
First Choice ◽  
Definition Of ◽  
Thermodynamical Laws ◽  
The Universe

A detailed thermodynamical study has been presented for the inhomogeneous FLRW-type model of the Universe bounded by a horizon with three possible modifications of Bekenstein–Hawking formulation of thermodynamical parameters namely entropy and temperature. For the first choice of the thermodynamical system validity of both the first law of thermodynamics (FLT) and the generalized second law of thermodynamics (GSLT) are examined. Also, the integrability conditions for the exact one-forms in both the thermodynamical laws are analyzed and it is found that they are consistent with each other. On the other hand, for the other two choices of the thermodynamical system to hold the first law of thermodynamics, one must restrict the parameters (in the definition of the thermodynamical variables) in some specific integral form.

Thermodynamics of squared speed of sound parametrizations

2020 ◽  
Vol 17 (05) ◽  
pp. 2050072
Author(s):  
Abdul Jawad ◽  
Sadaf Butt ◽  
Aneesa Majeed
Keyword(s):  
Thermodynamic Equilibrium ◽  
Speed Of Sound ◽  
Thermal Equilibrium ◽  
Apparent Horizon ◽  
Second Law Of Thermodynamics ◽  
Second Order ◽  
Second Law ◽  
Total Entropy ◽  
Generalized Second Law

In this work, an attempt is made to study the thermodynamical analysis at the apparent horizon in the framework of fractal universe. We consider the Bekenstein entropy to examine validity of the generalized second law of thermodynamics (GSLT) and thermal equilibrium for the four different cases which are developed with the utilization of different forms of squared speed of sound. In each case, we explore the behavior of total entropy through the graphical variation of its first- and second-order derivatives with respect to redshift parameter ([Formula: see text]). It is found that generalized second law of thermodynamics holds for Cases 1 and 2 for [Formula: see text] and [Formula: see text], respectively and it holds in late times as well. However, for Cases [Formula: see text] and [Formula: see text], this law is satisfied in early, present and future epochs. Furthermore, for Cases 1 and 2, instability of thermodynamic equilibrium is observed, but for Cases 3 and 4, it holds in the specific intervals [Formula: see text] and [Formula: see text], respectively.

Dynamic study of Weyl tensor corrected f(R) gravity

2021 ◽  
Author(s):  
Abdul Malik Sultan ◽  
Abdul Jawad
Keyword(s):  
Weyl Tensor ◽  
Thermal Equilibrium ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Second Law Of Thermodynamics ◽  
Positive Behavior ◽  
Second Law ◽  
Generalized Second Law ◽  
Equation Of State Parameter ◽  
Thermal Equilibrium Condition

We investigate the cosmological and thermodynamic aspects of Weyl tensor corrected [Formula: see text] gravity. For this purpose, we assume some well-known cosmological bouncing scenarios such as symmetric bounce cosmology, oscillatory cosmology, matter bounce cosmology, little rip cosmology, superbounce cosmology and develop some cosmological parameters. For instance, the equation of state parameter [Formula: see text] describes the quintessence phase for symmetric bounce cosmology, vacuum phase for oscillatory, little rip and matter bounce cosmology while it gives both quintessence and vacuum phases for matter bounce cosmology. It is also observed that the squared speed of sound [Formula: see text] gives positive behavior for all models resulting in that the models assumed are stable. We evaluate generalized second law of thermodynamics which remains valid for all cosmological models except symmetric bounce cosmology. Moreover, we also investigate the thermal equilibrium condition [Formula: see text] and found its validity for all models except symmetric bounce cosmological model.

scholarly journals THERMODYNAMICS IN CLOSED UNIVERSE WITH ENTROPY CORRECTIONS

2013 ◽  
Vol 22 (03) ◽  
pp. 1350014 ◽  
Author(s):  
M. SHARIF ◽  
ABDUL JAWAD
Keyword(s):  
Critical Mass ◽  
Second Law Of Thermodynamics ◽  
Phantom Energy ◽  
Chaplygin Gas ◽  
Upper And Lower Bounds ◽  
Closed Universe ◽  
Generalized Chaplygin Gas ◽  
Event Horizons ◽  
Generalized Second Law ◽  
Horizon Entropy

We discuss the generalized second law of thermodynamics (GSLT) in three different systems by taking quantum corrections (logarithmic and power law) to cosmological horizon entropy as well as black hole (BH) entropy. First, we consider phantom energy accretion onto the Schwarzschild BH in the closed Friedmann–Robertson–Walker universe and investigate the validity of the GSLT on the apparent and event horizons. In another scenario, we evaluate the critical mass of the Schwarzschild BH with upper and lower bounds under accretion process due to phantom-like modified generalized chaplygin gas. It is found that the GSLT is respected within these bounds and BH cannot accrete outside them. Finally, we explore this law for a closed universe filled with interacting n-components of fluid (in thermal equilibrium case) and with noninteracting dark matter and dark energy components (in thermal nonequilibrium case) on the apparent and event horizons and find conditions for its validity.

The Analogical Turn (1884–1887)

2018 ◽  
Author(s):  
Olivier Darrigol
Keyword(s):  
Boltzmann Equation ◽  
Statistical Mechanics ◽  
Mechanical System ◽  
Thermal Equilibrium ◽  
Special Kind ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Equipartition Theorem ◽  
Royal Road ◽  
H Theorem

This chapter recounts how Boltzmann reacted to Hermann Helmholtz’s analogy between thermodynamic systems and a special kind of mechanical system (the “monocyclic systems”) by grouping all attempts to relate thermodynamics to mechanics, including the kinetic-molecular analogy, into a family of partial analogies all derivable from what we would now call a microcanonical ensemble. At that time, Boltzmann regarded ensemble-based statistical mechanics as the royal road to the laws of thermal equilibrium (as we now do). In the same period, he returned to the Boltzmann equation and the H theorem in reply to Peter Guthrie Tait’s attack on the equipartition theorem. He also made a non-technical survey of the second law of thermodynamics seen as a law of probability increase.

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