Results 61 to 70 of about 11,605 (193)
The Friedmann-Lemaitre-Robertson-Walker Big Bang singularities are well behaved
, 2015 We show that the Big Bang singularity of the Friedmann-Lemaitre-Robertson-Walker model does not raise major problems to General Relativity. We prove a theorem showing that the Einstein equation can be written in a non-singular form, which allows the ...
A Ashtekar +35 more
core +1 more source
Kaniadakis Holographic Dark Energy Behavior in f(Q) Theory
Fortschritte der Physik, Volume 74, Issue 4, April 2026.ABSTRACT In this study, the cosmological behavior of the Kaniadakis holographic dark energy model is investigated under the f(Q)$f(Q)$ theory within the framework of a flat Friedmann–Robertson–Walker (FRW) universe. The generalized holographic energy density based on Kaniadakis entropy is modeled using the Hubble horizon infrared cutoff scale, and the ...
Sinem Kalkan, Can Aktaş
wiley +1 more source
Could a thin-shell configuration lie hidden within the universe?
European Physical Journal C: Particles and FieldsThis article explores the cosmological scenario in which our Universe contains a hidden thin-shell configuration. We investigate a degenerate modification of the Friedmann-Robertson-Walker metric obtained through a coordinate transformation applied to ...
Mauricio Cataldo +2 more
doaj +1 more source
Singular shell embedded into a cosmological model
, 2003 We generalize Israel's formalism to cover singular shells embedded in a non-vacuum Universe. That is, we deduce the relativistic equation of motion for a thin shell embedded in a Schwarzschild/Friedmann-Lemaitre-Robertson-Walker spacetime.
A. Corichi +42 more
core +1 more source
Fermion production from preheating-amplified metric perturbations [PDF]
, 2001 We study gravitational creation of light fermions in the presence of classical scalar metric perturbations about a flat Friedmann-Lemaitre- Robertson-Walker (FLRW) background.
Bassett, Bruce A. +3 more
core +2 more sources
A Re‐Examination of Foundational Elements of Cosmology
Fortschritte der Physik, Volume 74, Issue 3, March 2026.ABSTRACT This paper undertakes a conceptual re‐examination of several foundational elements of cosmology through the lens of spacetime symmetries. A new derivation of the Friedmann–Lemaître–Robertson–Walker metric is obtained by a careful conceptual examination of rotations and translations on generic manifolds, followed by solving the rotational and ...
Lavinia Heisenberg
wiley +1 more source
Supersymmetric Majorana Quantum Cosmologies
, 2015 The Einstein equations for an isotropic and homogeneous Friedmann--Robertson--Walker Universe in the presence of a quintessence scalar field are shown to be described in a unified way, formally identical to the dynamics of a relativistic particle moving ...
Asenjo, Felipe A., Hojman, Sergio A.
core +2 more sources
Generation of seed perturbations from Quantum Cosmology [PDF]
, 1992 The origin of seed perturbations in the Universe is studied within the framework of a specific minisuperspace model. It is shown that the `creation' of the Universe as a result of a quantum transition from a flat empty spacetime would lead to a flat FLRW
Souradeep, Tarun
core +2 more sources
Logarithmic and Strong Coupling Models in Weyl‐Type f(Q,T)$f(Q,T)$ Gravity
Annalen der Physik, Volume 538, Issue 1, January 2026.This work explores Weyl‐type f(Q,T) gravity using recent observational datasets — CC, Pantheon+, Union 3.0, and DESI DR2. Through MCMC analysis of logarithmic and strong coupling models, the study reveals a transition from deceleration to acceleration, quintessence‐to‐phantom dynamics, and late‐time consistency with LCDM, offering a geometry‐driven ...
Rahul Bhagat, S. K. Tripathy, B. Mishra
wiley +1 more source
, 2015 We discuss the relationship between the Noether point symmetries of the geodesic Lagrangian, in a (pseudo)Riemannian manifold, with the elements of the Homothetic algebra of the space.
Krishnakumar, K. +2 more
core +1 more source