Results 101 to 110 of about 11,605 (193)

Time Delay in Robertson-McVittie Spacetime and its Application to Increase of Astronomical Unit

, 2008
We investigated the light propagation by means of the Robertson-McVittie solution which is considered to be the spacetime around the gravitating body embedded in the FLRW (Friedmann-Lema{\^i}tre-Robertson-Walker) background metric. We concentrated on the
Asada, Bretagnon, Cooperstock, de Felice, de Felice, Einstein, Einstein, Fairhead, Faraoni, Fienga, Gautreau, Hellings, Hideyoshi Arakida, Järnefelt, Järnefelt, Järnefelt, Klioner, Klioner, Kopeikin, Kopeikin, Kopeikin, Krasinsky, Mashhoon, McVittie, Moyer, Moyer, Noerdlinger, Nolan, Nolan, Pitjeva, Richter, Robertson, Schücking, Seidelmann, Sereno, Shapiro, Soffel, Standish, Standish, Will   +39 more
core   +1 more source

Multiple-scales analysis of cosmological perturbations in brane-worlds

, 2004
We present a new approximation method for solving the equations of motion for cosmological tensor perturbations in a Randall-Sundrum brane-world model of the type with one brane in a five-dimensional anti-de Sitter spacetime.
Battye, Richard A., Mennim, Andrew
core   +1 more source

FRW Universe Models in Conformally Flat Spacetime Coordinates. III: Universe models with positive spatial curvature

, 2011
We deduce general expressions for the line element of universe models with positive spatial curvature described by conformally flat spacetime coordinates. Models with dust, radiation and vacuum energy are exhibited.
A. Lasenby, E. Eriksen, G. Endean, G. Endean, G. Endean, G.U. Varieschi, L. Querella, M. Ibison, O. Grøn, O. Grøn   +9 more
core   +1 more source

Weighing the curvature invariants

European Physical Journal C: Particles and Fields
We prove several inequalities between the curvature invariants, which impose constraints on curvature singularities. Some of the inequalities hold for a family of spacetimes which include static, Friedmann–Lemaître–Robertson–Walker, and Bianchi type I ...
Jan Dragašević, Ina Moslavac, Ivica Smolić   +2 more
doaj   +1 more source

On the Necessity of Phantom Fields for Solving the Horizon Problem in Scalar Cosmologies

Universe, 2019
We discuss the particle horizon problem in the framework of spatially homogeneous and isotropic scalar cosmologies. To this purpose we consider a Friedmann–Lemaître–Robertson–Walker (FLRW) spacetime with possibly non-zero spatial ...
Davide Fermi, Massimo Gengo, Livio Pizzocchero   +2 more
doaj   +1 more source

Signatures of primordial gravitational waves in matter power spectrum

European Physical Journal C: Particles and Fields, 2019
We simulate the evolution of a dust universe from $$z=1089$$ z=1089 to $$z=0$$ z=0 by numerically integrating the Einstein’s equation for a spatially flat Friedmann–Lemaire–Robertson–Walker (FLRW) background spacetime with scalar perturbations which are ...
Ke Wang
doaj   +1 more source

Gravity-induced entanglement between two massive microscopic particles in curved spacetime: II. Friedmann–Lemaître–Robertson–Walker universe

European Physical Journal C: Particles and Fields
In our previous work (Zhang and Shu in Eur Phys J. C 84(3):256, 2024), we have explored quantum gravity induced entanglement of masses (QGEM) in curved spacetime, observing entanglement formation between particles moving along geodesics in a ...
Chi Zhang, Fu-Wen Shu
doaj   +1 more source

On the Effects of Non-Metricity in an Averaged Universe

Universe
In the covariant averaging scheme of macroscopic gravity, the process of averaging breaks the metricity of geometry. We reinterpret the back-reaction within macroscopic gravity in terms of the non-metricity of averaged geometry.
Anish Agashe, Sai Madhav Modumudi
doaj   +1 more source

Constraining barrow entropy-based cosmology with power-law inflation. [PDF]

Eur Phys J C Part Fields, 2023
Luciano GG.
europepmc   +1 more source

Shock waves in the Friedmann-Robertson-Walker spacetime [PDF]

Proceedings of The XIXth International Workshop on High Energy Physics and Quantum Field Theory — PoS(QFTHEP2010), 2011
Ekaterina Pozdeeva, Irina Arefeva
openaire   +1 more source