Results 21 to 30 of about 6,154 (134)
A new approach to the study of spacelike submanifolds in a spherical Friedmann–Lemaître–Robertson–Walker spacetime: characterization of the stationary spacelike submanifolds as an application [PDF]
Journal of Physics A: Mathematical and Theoretical, 2022 A natural codimension one isometric embedding of each (n+1) -dimensional spherical Friedmann–Lemaître–Robertson–Walker (FLRW) spacetime I×fSn in the (n+2) -dimensional Lorentz–Minkowski spacetime Ln+2 permits to contemplate I×fSn as a rotation Lorentzian
D. Ferreira +3 more
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Probing spatial orientability of a Friedmann-Robertson-Walker spatially flat spacetime [PDF]
Physical Review D, 2021 One important global topological property of a spacetime manifold is orientability. It is widely believed that spatial orientability can only be tested by global journeys around the Universe to check for orientation-reversing closed paths.
N. A. Lemos, D. Müller, M. Rebouças
semanticscholar +1 more source
Estimation of temperature of cosmological apparent horizons: a new approach
European Physical Journal C: Particles and Fields, 2021 We consider radiation from cosmological apparent horizon in Friedmann–Lemaitre–Robertson–Walker (FLRW) model in a double-null coordinate setting. As the spacetime is dynamic, there is no timelike Killing vector, instead we have Kodama vector which acts ...
Bhramar Chatterjee, Narayan Banerjee
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Covariant Space-Time Line Elements in the Friedmann–Lemaitre–Robertson–Walker Geometry
Axioms, 2022 Most quantum gravity theories quantize space-time on the order of Planck length (ℓp ). Some of these theories, such as loop quantum gravity (LQG), predict that this discreetness could be manifested through Lorentz invariance violations (LIV) over ...
David Escors, Grazyna Kochan
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Local Causality in a Friedmann-Robertson-Walker Spacetime [PDF]
, 2014 A local, deterministic, and realistic model within a Friedmann-Robertson-Walker spacetime with constant spatial curvature (S^3) is presented which describes simultaneous measurements of the spins of two fermions emerging in a singlet state from the decay
J. Christian
semanticscholar +1 more source
Assisted inflation in Friedmann-Robertson-Walker and Bianchi spacetimes [PDF]
Physical Review D, 2000 We use exact general solutions for the spatially flat FRW and the anisotropic Bianchi I cosmologies to show that generically uncoupled scalar fields cooperate to make inflation more probable, while the presence of several interacting fields hinders the occurrence of the phenomenon, in accordance with previous results based on particular power-law ...
Chimento, Luis Pascual +3 more
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Stress-energy tensor of adiabatic vacuum in Friedmann-Robertson-Walker spacetimes [PDF]
Journal of Cosmology and Astroparticle Physics, 2011 We compute the leading order contribution to the stress-energy tensor corresponding to the modes of a quantum scalar field propagating in a Friedmann-Robertson-Walker universe with arbitrary coupling to the scalar curvature, whose exact mode functions can be expanded as an infinite adiabatic series.
Kaya, Ali, Tarman, Merve
openaire +2 more sources
Scalar Field Evolution at Background and Perturbation Levels for a Broad Class of Potentials
Fortschritte der Physik, Volume 71, Issue 10-11, November 2023., 2023 Abstract In this paper, a non‐interacting scalar field cosmology with an arbitrary potential using the f‐deviser method that relies on the differentiability properties of the potential is investigated. Using this alternative mathematical approach, a unified dynamical system analysis at a scalar field's background and perturbation levels with arbitrary ...
Genly Leon +5 more
wiley +1 more source
NONASSOCIATIVE GEOMETRY: FRIEDMANN–ROBERTSON–WALKER SPACETIME [PDF]
, 2004 In (Phys. Rev. D62 (2000) 081501(R)) we proposed a unified description of continuum and discrete spacetime based on nonassociative geometry. It follows from our approach that at distances comparable with Planck length the standard concept of spacetime ...
A. Nesterov, L. Sabinin
semanticscholar +1 more source
Dynamical Analysis in Chameleon Dark Energy
Fortschritte der Physik, Volume 71, Issue 8-9, September 2023., 2023 Abstract A detailed analysis of the phase‐space for the field equations in scalar field cosmology with a chameleon cosmology in a spatially flat Friedmann–Lemaître–Robertson–Walker spacetime is presented. For the matter source it is assumed that it is an ideal gas with a constant equation of state parameter, while for the scalar field potential and the
Andronikos Paliathanasis
wiley +1 more source