Related papers: Cooling-Heating Properties of the FRW Universe in …
The analysis of phase transitions in cosmological spacetimes shows that their existence requires a time-dependent apparent horizon radius, which in turn implies an equation of state different from that of a dark energy fluid. This condition…
We derive self-similar solutions including cooling and heating in an Einstein de-Sitter universe, and investigate the effects of cooling and heating on the gas density and temperature distributions. We assume that the cooling rate has a…
Researches in the several decades have shown that the dynamics of gravity is closely related to thermodynamics of the horizon. In this paper, we derive the Friedmann acceleration equation based on the idea of "emergence of space" and…
The present thesis is focused on the study of FLRW cosmology in modified gravities and with scalar fields. The mystery of dark energy has made that the last decade, many efforts in theoretical physics have been focused on the explanation of…
In the present paper, we study the thermodynamics behavior of the field equations for the generalized f(T) gravity with an arbitrary coupling between matter and the torsion scalar. In this regard, we explore the verification of the first…
We present a dynamical analysis of the (classical) spatially flat and negative curved Friedmann-Lameitre-Robertson-Walker (FLRW) universes evolving, (by assumption) close to the thermodynamic equilibrium, in presence of a particles creation…
The present work examines the possibility of warm inflationary paradigm in the modified gravity theory with fractal geometry. By choosing the normal fluid as radiation fluid and the effective fluid (with the extra term in modified field…
The paper deals with cosmological solutions describing different phases of the Universe for the homogeneous and isotropic FLRW model of the Universe with torsion. Normally, torsion field is not suitable for maximally symmetric space time…
We present a second-order gauge-invariant formalism to study the evolution of curvature perturbations in a Friedmann-Robertson-Walker universe filled by multiple interacting fluids. We apply such a general formalism to describe the…
This paper deals with gravitational thermodynamics on the dynamical apparent horizon of an FLRW universe with dissipation. The dissipation is assumed to arise due to adiabatic gravitational particle creation. For the thermodynamic study, we…
Two of the three gases that display isenthalpic Joule-Thomson (J-T) warming under laboratory conditions are hydrogen and helium, the main constituents of the solar plasma, but the temperatures that are attained by this route are at most a…
We find phase transitions and critical phenomena of the FRW (Friedmann-Robertson-Walker) universe in the framework of an effective scalar-tensor theory that belongs to the Horndeski class. We identify the thermodynamic pressure (generalized…
One of the questions in the cosmology courses is the cooling mechanism of cosmic fluid during it expansion according to classical concepts of the thermodynamics. In this short pedagogical paper, we quote the questions and give a natural…
This paper investigates the finite-temperature behavior of Conformal Field Theory (CFT) in Rindler vacuum, focusing on the relation between acceleration and thermality in quantum field theory. We illustrate how uniformly accelerated…
The late time evolution of Friedmann-Robertson-Walker (FRW) models with a perfect fluid matter source is studied in the conformal frame of $f(R) $ gravity. We assume that the corresponding scalar field, nonminimally coupled to matter, has…
A cubic correction of $f(T)$ gravity, where $T$ is the teleparallel scalar torsion, is considered to describe gravity in spatially flat Friedmann-Robertson-Walker model. A scale factor permitting departure from inflation era has been…
In this paper we study Joule-Thomson $(JT)$ expansion of non-linearly charged $AdS$ black holes in Einstein-power-Yang-Mills (EPYM) gravity in $D$ dimensions. Within the framework of extended phase space thermodynamics we identify the…
In this paper we use the conformal teleparallel gravity to study an isotropic and homogeneous Universe which is settled by the FRW metric. We solve the field equations and we obtain the behavior of some cosmological parameters such as scale…
The thermodynamical process of Joule-Thomson expansion is extended to the lower-dimensional spacetimes by considering rotating, charged and charged rotating BTZ black hole metrics. The Joule-Thomson coefficients, the inversion curves and…
We use the Brans-Dicke theory from the framework of General Relativity (Einstein frame), but now the total energy momentum tensor fulfills the following condition $\rm <[\{1}{\phi}T^{\mu \nu M}+T^{\mu \nu}(\phi)>]_{;\nu}=0$. We take as a…