Results 91 to 100 of about 1,549,906 (171)

Rainich-type Conditions for Perfect Fluid Spacetimes [PDF]

, 2014
In this worksheet we describe and illustrate a relatively simple set of new Rainich-type conditions on an n-dimensional spacetime which are necessary and sufficient for it to define a perfect fluid solution of the Einstein field equations. Procedures are
Torre, Charles G, Dionisios Krongos, Charles G. Torre, Krongos, Dionisios   +3 more
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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

Lanczos Potentials in Perfect Fluid Cosmologies

, 2004
We derive the equation linking the Weyl tensor with its Lanczos potential, called the Weyl-Lanczos equation, in 1+3 covariant formalism for perfect fluid Bianchi type I spacetime and find an explicit expression for a Lanczos potential of the Weyl tensor ...
Holgersson, David
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Perfect Symmetries [PDF]

, 2007
While empirical symmetries relate situations, theoretical symmetries relate models of a theory we use to represent them. An empirical symmetry is perfect if and only if any two situations it relates share all intrinsic properties. Sometimes one can use a
Healey, Richard
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( α,β )- TYPE ALMOST η-RICCI-YAMABE SOLITONS IN PERFECT FLUID SPACETIME

In this paper, we consider perfect fluid spacetime admitting (alpha, beta)type almost eta-Ricci-Yamabe solitons by means of some curvature tensors. Ricci pseudosymmetry concepts of perfect fluid spacetime admitting (alpha, beta)-type almost eta-Ricci ...
Pandey, S., Mert, T., Atceken, M.
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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

Perfect Circle's Plant in Richmond, Indiana

, 1940
Luvena Dethridge sang in concerts while holding various jobs. After working at Reid Memorial Hospital as a cook, laundress, and maid, she worked as a piston inspector for the Perfect Circle plant in Richmond in the 1940s. A contract for a concert in 1945
Perfect Circle Company
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Spacetime and Reality: Facing the Ultimate Judge [PDF]

, 2012
Over a hundred years ago in his paper "Space and Time" Hermann Minkowski demonstrated the profound meaning of the relativity postulate - the experimental fact that physical phenomena are the same in all inertial reference frames implies that the ...
Petkov, Vesselin
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