Results 101 to 110 of about 18,336 (194)

Hyperbolic Ricci solitons on perfect fluid spacetimes

AIMS Mathematics
<abstract><p>In the present paper, we investigate perfect fluid spacetimes and perfect fluid generalized Roberston-Walker spacetimes that contain a torse-forming vector field satisfying almost hyperbolic Ricci solitons. We show that the perfect fluid spacetimes that contain a torse-forming vector field satisfy an almost hyperbolic Ricci ...
Shahroud Azami, Mehdi Jafari, Nargis Jamal, Abdul Haseeb   +3 more
openaire   +2 more sources

Generalized Euler equation from effective action: implications for the smarr formula in AdS black holes

Journal of High Energy Physics
We derive a generalized Euler equation, ϵ + p = sT + μq + y ∂ p ∂ y $$ y\frac{\partial p}{\partial y} $$ , using the effective field theory formulation of perfect fluids. This generalization was achieved by introducing a new variable y into the effective
Robinson Mancilla
doaj   +1 more source

Dynamical system analysis of a three fluid cosmological model: an invariant manifold approach

European Physical Journal C: Particles and Fields, 2019
The present paper considers a three-fluid cosmological model consisting of noninteracting dark matter, dark energy and baryonic matter in the background of the Friedman–Robertson–Walker–Lemaître flat spacetime.
Subhajyoti Pal, Subenoy Chakraborty
doaj   +1 more source

Spacetime Exterior to a Star: Against Asymptotic Flatness

Open Physics, 2016
In many circumstances the perfect fluid conservation equations can be directly integrated to give a geometric-thermodynamic equation: typically that the lapse N is the reciprocal of the enthalphy h, (N = 1/h). This result is aesthetically appealing as it
Roberts Mark D.
doaj   +1 more source

The spacetime geodesy of perfect fluid spheres

Herein we shall argue for the utility of "spacetime geodesy", a point of view where one delays as long as possible worrying about dynamical equations, in favour of the maximal utilization of both symmetries and geometrical features. This closely parallels Weinberg's distinction between "cosmography" and "cosmology", wherein maximal utilization of both ...
Simmonds, Christopher, Visser, Matt
openaire   +2 more sources

Charged Weyssenhoff fluid spheres in Einstein–Cartan–Maxwell theory: a general algorithm

European Physical Journal C: Particles and Fields
We construct exact static, spherically symmetric charged fluid solutions within the framework of Einstein–Cartan–Maxwell (ECM) theory, in which intrinsic spin and spacetime torsion are incorporated through the Weyssenhoff spin fluid.
L. N. Katkar, D. R. Phadatare
doaj   +1 more source

Observational constraints on the Kerr and its several single-parameter modified spacetimes using quasi-periodic oscillation data

European Physical Journal C: Particles and Fields
This paper investigates the dynamical effects of particles moving in the Kerr spacetime and its nine single-parameter modified spacetimes, including Bardeen, Ayon-Beato and Garcia (ABG), Hayward, Kerr–Newman (KN), Kerr–Taub–NUT (KTN), Braneworld Kerr (BK)
Shining Yang, Jianbo Lu, Wenmei Li, Mou Xu, Jingyang Xu   +4 more
doaj   +1 more source

Conformal Einstein solitons on a perfect fluid spacetime

Boletim da Sociedade Paranaense de Matemática
The objective of this research is to investigate the geometrical composition of a perfect fluid spacetime with a torse-forming vector field in connection with Conformal Einstein Soliton and Conformal -Einstein Soliton. Also, We have studied the conditions for a Conformal Einstein Soliton to be shrinking or expanding or steady.
Shivaprasanna G. S., Md. Samiul Haque, Somashekhara G.   +2 more
openaire   +1 more source

More on the first-order thermodynamics of scalar-tensor and Horndeski gravity. [PDF]

Eur Phys J C Part Fields, 2023
Faraoni V, Houle J.
europepmc   +1 more source

Perfect fluid spacetimes with harmonic generalized curvature tensor [PDF]

, 2019
We show that n-dimensional perfect fluid spacetimes with divergence-free conformal curva- ture tensor and constant scalar curvature are generalized Robertson Walker (GRW) spacetimes; as a consequence a perfect fluid Yang pure space is a GRW spacetime.
C. A. Mantica, U. C. De, Y. J. Suh, L. G. Molinari   +3 more
openaire   +2 more sources