scholarly journals Thermodynamics of the apparent horizon in the generalized energy–momentum-squared cosmology

2021 ◽  
pp. 100849
Author(s):  
Prabir Rudra ◽  
Behnam Pourhassan
Keyword(s):  
Apparent Horizon

scholarly journals Two physical characteristics of numerical apparent horizons

2008 ◽  
Vol 86 (4) ◽  
pp. 669-673 ◽  
Author(s):  
I Booth
Keyword(s):  
General Relativity ◽  
Apparent Horizon ◽  
Physical Characteristics ◽  
Apparent Horizons

This article translates some recent results on quasilocal horizons into the language of (3 + 1) general relativity to make them more useful to numerical relativists. In particular, quantities are described that characterize how quickly an apparent horizon is evolving and how close it is to either equilibrium or extremality.PACS Nos.: 04.20.Cv, 04.25.Dm, 04.70.Bw

Hypnosis and Perception: The Effect of Meaning and Nonmeaning upon the Perception of the Apparent Horizon

1964 ◽  
Vol 57 (1) ◽  
pp. 219-233
Author(s):  
Kenneth A. Chandler ◽  
Daniel X. Freedman ◽  
William L. Savage
Keyword(s):  
Apparent Horizon

scholarly journals Test-beds and applications for apparent horizon finders in numerical relativity

2000 ◽  
Vol 17 (11) ◽  
pp. 2159-2190 ◽  
Author(s):  
M Alcubierre ◽  
S Brandt ◽  
B Brügmann ◽  
C Gundlach ◽  
J Massó ◽  
...  
Keyword(s):  
Numerical Relativity ◽  
Apparent Horizon ◽  
Test Beds

scholarly journals An effective cosmological constant from an entropic formulation of gravity

2020 ◽  
Vol 29 (09) ◽  
pp. 2050064
Author(s):  
I. Díaz-Saldaña ◽  
J. C. López-Domínguez ◽  
M. Sabido
Keyword(s):  
Cosmological Constant ◽  
Apparent Horizon ◽  
Friedmann Equation ◽  
Scale Factor ◽  
Late Time ◽  
Frw Universe ◽  
Equation Solving ◽  
Effective Cosmological Constant ◽  
Time Regime ◽  
Modified Entropy

In this work, we study a Friedmann–Robertson–Walker (FRW) universe derived from a modified entropy–area relationship. By applying the first law of thermodynamics to the so-called apparent horizon and a modified entropy–area relationship, we obtain a modified Friedmann equation. Solving this model for a perfect fluid with vanishing cosmological constant, we find that for early times, the scale factor is the same as that of an FRW universe. In the late-time regime, although the cosmological constant is zero, the asymptotic behavior of the scale factor is exponential, and therefore, we can identify an effective cosmological constant. The origin of the effective cosmological constant can be traced to the modifications of the entropy–area relation.

Cosmological constraints on the variable modified Chaplygin gas model by using MCMC approach

2015 ◽  
Vol 24 (08) ◽  
pp. 1550059 ◽  
Author(s):  
Jian-bin Chen ◽  
Zhen-qi Liu ◽  
Lili Xing
Keyword(s):  
Apparent Horizon ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Acoustic Oscillations ◽  
Microwave Background ◽  
Mean Values ◽  
Cosmological Constraints ◽  
Variable Modified Chaplygin Gas ◽  
Type Ia ◽  
Ia Supernovae

We investigate the cosmological constraints on the variable modified Chaplygin gas (VMCG) model from the latest observational data: Union2 dataset of Type Ia supernovae (SNIa), the observational Hubble data (OHD), the baryon acoustic oscillations (BAO) and the cosmic microwave background (CMB) data. By using the Markov chain Monte Carlo (MCMC) method, we obtain the mean values of parameters in the flat model: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. Furthermore, we investigate the thermodynamical properties of VMCG model at apparent horizon, event horizon and particle horizon respectively.

The wormhole thermodynamics in f (R ) gravity

2019 ◽  
Vol 35 (04) ◽  
pp. 1950360 ◽  
Author(s):  
A. S. Sefiedgar ◽  
M. Mirzazadeh
Keyword(s):  
Continuity Equation ◽  
Energy Momentum Tensor ◽  
Apparent Horizon ◽  
Second Law Of Thermodynamics ◽  
Momentum Tensor ◽  
Second Law ◽  
Standard Entropy ◽  
Field Equations ◽  
First Law Of Thermodynamics ◽  
Generalized Second Law

Thermodynamics of the evolving Lorentzian wormhole at the apparent horizon is investigated in [Formula: see text] gravity. Redefining the energy density and the pressure, the continuity equation is satisfied and the field equations in [Formula: see text] gravity reduce to the ones in general relativity. However, the energy–momentum tensor includes all the corrections from [Formula: see text] gravity. Therefore, one can apply the standard entropy-area relation within [Formula: see text] gravity. It is shown that there may be an equivalency between the field equations and the first law of thermodynamics. It seems that an equilibrium thermodynamics may be held on the apparent horizon. The validity of the generalized second law of thermodynamics (GSL) is also investigated in the wormholes.

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