Results 61 to 70 of about 2,969 (164)
Communications PhysicsCosmology faces major observational challenges arising from the spatial and temporal scales involved. Analogue experiments that recreate cosmological scenarios in the laboratory offer a valuable means to probe and better understand the current tensions ...
Felipe A. Asenjo +2 more
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European Physical Journal C: Particles and Fields, 2023 Fast Radio Bursts (FRBs) are millisecond-duration radio transients with an observed dispersion measure (DM) greater than the expected Milky Way contribution, which suggests that such events are of extragalactic origin.
Thais Lemos +3 more
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On Cosmological Evolution of Quasars [PDF]
Symposium - International Astronomical Union, 1987 Hereafter the term “quasar” is applied to both optically selected (and/or spectroscopically confirmed) UVX objects, and to radio-detected objects of that kind. A recent attempt to model number-counts of radio-selected QSOs (Condon, private communication) has revealed that the counts cannot be modelled by simply translating the general radio luminosity ...
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Perturbation evolution in cosmologies with a decaying cosmological constant [PDF]
Physical Review D, 1998 Structure formation models with a cosmological constant are successful in explaining large-scale structure data, but are threatened by the magnitude-redshift relation for Type Ia supernovae. This has led to discussion of models where the cosmological `constant' decays with time, which might anyway be better motivated in a particle physics context.
Viana, Pedro T P, Liddle, Andrew R
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Advances in High Energy Physics, 2016 We study the stability of the cosmological scalar field models by using the Jacobi stability analysis, or the Kosambi-Cartan-Chern (KCC) theory. In this approach, we describe the time evolution of the scalar field cosmologies in geometric terms, by ...
Bogdan Dănilă +4 more
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Quantum Weyl invariance and cosmology
Physics Letters B, 2016 Equations for cosmological evolution are formulated in a Weyl invariant formalism to take into account possible Weyl anomalies. Near two dimensions, the renormalized cosmological term leads to a nonlocal energy-momentum tensor and a slowly decaying ...
Atish Dabholkar
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Unimodular gravity with arbitrary diffusion function: a dynamical system reconstruction approach
European Physical Journal C: Particles and FieldsWe investigate cosmological diffusion models in unimodular gravity within a dynamical systems reconstruction framework. By treating the logarithmic slope of the diffusion sector as an invertible dynamical variable, the diffusion function can be ...
Gabriel Gómez +2 more
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Constraining the minimally extended varying speed of light model using time dilations
Frontiers in Astronomy and Space SciencesThe Robertson–Walker (RW) metric, derived from the cosmological principle and Weyl’s postulate, characterizes the ΛCDM cosmological model. Traditionally, in this framework, the assumption of a constant speed of light leads to specific cosmological time ...
Seokcheon Lee
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East European Journal of PhysicsThis paper investigates Einstein’s field equations within a cosmological model that incorporates a polytropic bulk viscous fluid, with the gravitational and cosmological constants varying in a Bianchi type-I universe.
Archana Gajanan Ingle +5 more
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The cosmological models with jump discontinuities
European Physical Journal C: Particles and Fields, 2018 The article is dedicated to one of the most undeservedly overlooked properties of the cosmological models: the behaviour at, near and due to a jump discontinuity.
Artyom Yurov +2 more
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