Results 41 to 50 of about 11,605 (193)
Effective dynamics of scalar perturbations in a flat Friedmann-Robertson-Walker spacetime in loop quantum cosmology [PDF]
Physical Review D, 2014 We study the evolution of a homogeneous and isotropic spacetime whose spatial sections have three-torus topology, coupled to a massless scalar field with small scalar perturbations within loop quantum cosmology. We consider a proposal for the effective dynamics based on a previous hybrid quantization completed by us.
Fernández Méndez, Mikel +2 more
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Dynamic wormhole geometries in hybrid metric-Palatini gravity
European Physical Journal C: Particles and Fields, 2021 In this work, we analyse the evolution of time-dependent traversable wormhole geometries in a Friedmann–Lemaître–Robertson–Walker background in the context of the scalar–tensor representation of hybrid metric-Palatini gravity.
Mahdi Kord Zangeneh +1 more
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Ultraviolet-regularized power spectrum without infrared distortions in cosmological spacetimes
Physics Letters B, 2023 We reexamine the regularization of the two-point function of a scalar field in a Friedmann-Lemaitre-Robertson-Walker (FLRW) spacetime. Adiabatic regularization provides a set of subtraction terms in momentum space that successfully remove its ultraviolet
Antonio Ferreiro, Francisco Torrenti
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Cosmological perturbations and short distance physics from Noncommutative Geometry [PDF]
, 2002 We investigate the possible effects on the evolution of perturbations in the inflationary epoch due to short distance physics. We introduce a suitable non local action for the inflaton field, suggested by Noncommutative Geometry, and obtained by adopting
A. Connes +33 more
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European Physical Journal C: Particles and Fields, 2018 We numerically integrate the Einstein’s equations for a spatially flat Friedmann–Lemaire–Robertson–Walker (FLRW) background spacetime with a spatial curvature perturbation and evolving primordial tensor perturbations using the Einstein Toolkit.
Ke Wang
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Quantization of Friedmann-Robertson-Walker spacetimes in the presence of a negative cosmological constant and radiation [PDF]
Physical Review D, 2006 34 pages, 3 ...
Monerat, G. A. +4 more
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MathematicsApplications of Parametrized Relativistic Quantum Theory (PRQT) in curved spacetime are considered here. PRQT in curved spacetime is applied to the motion of free scalar particles in expanding universe metrics, including a generalized expanding universe (
John R. Fanchi
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Comment on “Quantization of Friedmann-Robertson-Walker spacetimes in the presence of a negative cosmological constant and radiation” [PDF]
Physical Review D, 2007 The quantization of the Friedmann-Robertson-Walker spacetime in the presence of a negative cosmological constant was used in a recent paper to conclude that there are solutions that avoid singularities (big bang-big crunch) at the quantum level.
Paolo Amore +4 more
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Physics Letters B, 2021 We demonstrate that the rapidity and robustness of slow contraction in homogenizing and flattening the universe found in simulations in which the initial conditions were restricted to non-perturbative variations described by a single Fourier mode along ...
Anna Ijjas +3 more
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Scalar field dynamics in Friedmann-Robertson-Walker spacetimes [PDF]
Physical Review D, 1997 We study the non-linear dynamics of quantum fields in matter and radiation dominated universes, using the non-equilibrium field theory approach combined with the non-perturbative Hartree and the large N approximations. We examine the phenomenon of explosive particle production due to spinodal instabilities and parametric amplification in expanding ...
Boyanovsky, D. +5 more
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