Zobrazeno 1 - 10
of 219
pro vyhledávání: '"Shojai, F"'
Publikováno v:
Eur. Phys. J. C 84, 979 (2024)
We consider the third law of thermodynamics for families of 4- and n-dimensional Vaidya black holes, including many of interest. Since there are several versions of the definition of surface gravity as well as the extremality condition for dynamical
Externí odkaz:
http://arxiv.org/abs/2409.18756
We introduce an ingenious approach to explore cosmological implications of higher-derivative gravity theories. The key novelty lies in the characterization of the additional massive spin-0 modes constructed from Hubble derivatives as an effective den
Externí odkaz:
http://arxiv.org/abs/2405.02879
Publikováno v:
Eur. Phys. J. C (2024) 84: 197
Here we consider the generalized Oppenheimer-Snyder collapse of a star into a four-dimensional Einstein-Gauss-Bonnet black hole as well as a class of regular black holes labeled by the polytropic index of the stellar matter. We then analyze the natur
Externí odkaz:
http://arxiv.org/abs/2402.07828
Publikováno v:
JCAP06(2024)002
We investigate various cosmological aspects of a 4-Dimensional Gauss-Bonnet Lagrangian, which is integrated into the Einstein Lagrangian with an arbitrary sign, using the Friedman-Lema\^itre-Robertson-Walker (FLRW) metric. We consider a general poten
Externí odkaz:
http://arxiv.org/abs/2311.15272
Publikováno v:
2023 Phys. Scr. 98 085310
Apart from the assumption that the inflation started at an infinite time in the past, the more realistic initial state of the quantum fluctuations is described by a mixed quantum state imposed at a finite value of the initial time. One of the most im
Externí odkaz:
http://arxiv.org/abs/2307.04196
Publikováno v:
Classical and Quantum Gravity, 2023
In this paper, we treat 4-dimensional Einstein-Gauss-Bonnet gravity as general relativity with an effective stress-energy tensor. We will study the modified Oppenheimer-Snyder-Datt model of the gravitational collapse of a star in a 4-dimensional Eins
Externí odkaz:
http://arxiv.org/abs/2302.10853
We shall study the formation of a particular class of regular black holes from the gravitational collapse of a massive star. The inside geometry is described by spatially flat Friedmann-Robertson-Walker metric and the stellar matter is distributed un
Externí odkaz:
http://arxiv.org/abs/2202.14024
Autor:
Rasouli, S. M. M., Shojai, F.
Publikováno v:
Physics of the Dark Universe 32 (2021) 100781
In this paper, we study the geodesic deviation equation (GDE) within the context of the Brans-Dicke (BD) theory in $D$ dimensions. Then, we restrict our attention to the GDE for the fundamental observers and null vector field past directed. Concernin
Externí odkaz:
http://arxiv.org/abs/2103.16612
Autor:
Saadati, R., Shojai, F.
Publikováno v:
Class. Quantum Grav. 38 (2021) 135025
We present some new aspects of Kiselev black hole and then study the null and timelike thin shell collapse in this spacetime. For the latter, we show that Kiselev black hole can be matched to de Sitter core with a thin timelike dust shell to produce
Externí odkaz:
http://arxiv.org/abs/2009.06990
Autor:
Khodabakhshi, H., Shojai, F.
Using some probes, the violation of cosmic censorship conjecture in a general Kerr-Newman black hole is investigated. The result depends on many factors, like the relative sign of charge and rotation direction of the probe and black hole. Moreover th
Externí odkaz:
http://arxiv.org/abs/2008.02358