Results 41 to 50 of about 4,839,190 (320)
The Astrophysical Journal Letters, 2023 The light from an extragalactic source at a distance d will arrive at detectors separated by 100 au at times that differ by as much as 120( d /100 Mpc) ^−1 nanoseconds because of the curvature of the wave front. At gigahertz frequencies, the arrival time
Kyle Boone, Matthew McQuinn
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The Pantheon+ Analysis: Cosmological Constraints [PDF]
Astrophysical Journal, 2022 We present constraints on cosmological parameters from the Pantheon+ analysis of 1701 light curves of 1550 distinct Type Ia supernovae (SNe Ia) ranging in redshift from z = 0.001 to 2.26.
D. Brout +47 more
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Inflation and cosmological constant [PDF]
Physica Scripta, 2021 Abstract In construction of an inflationary model, one usually assumes that the matter sector of the gravitational action is minimally coupled to the background. It means that the matter (inflaton) part of the action is coupled with the same metric of the gravitational part.
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Graduated dark energy: Observational hints of a spontaneous sign switch in the cosmological constant [PDF]
Physical Review D, 2019 We study the cosmological constant (Λ) in the standard Λ cold dark matter model by introducing the graduated dark energy (gDE) characterized by a minimal dynamical deviation from the null inertial mass density of the Λ in the form ρinert ...
Ö. Akarsu +3 more
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Vacuum energy with mass generation and Higgs bosons
Physics Letters B, 2020 We discuss the Higgs mass and cosmological constant hierarchy puzzles with emphasis on the interplay of Poincaré invariance, mass generation and renormalization group invariance.
Steven D. Bass, Janina Krzysiak
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Brans–Dicke Gravity with a Cosmological Constant Smoothes Out ΛCDM Tensions [PDF]
Astrophysical Journal, 2019 We analyze Brans–Dicke gravity with a cosmological constant, Λ, and cold dark matter (BD-ΛCDM) in the light of the latest cosmological observations on distant supernovae, Hubble rate measurements at different redshifts, baryonic acoustic oscillations ...
J. Peracaula +3 more
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Is There a Cosmological Constant? [PDF]
The Astrophysical Journal, 1996 We present limits on the cosmological constant from the statistics of gravitational lenses using newly completed quasar surveys, new lens data, and a range of lens models. The formal limit is $λ_0 < 0.66$ at 95\% confidence in flat cosmologies, including the statistical uncertainties in the number of lenses, galaxies, quasars, and the parameters ...
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THE COSMOLOGICAL CONSTANT [PDF]
String Phenomenology, 2003 Various contributions to the cosmological constant are discussed and confronted with its recent measurement. We briefly review different scenarious -- and their difficulties -- for a solution of the cosmological constant problem.
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Black hole spontaneous scalarisation with a positive cosmological constant [PDF]
Physics Letters B, 2019 A scalar field non-minimally coupled to certain geometric [or matter] invariants which are sourced by [electro]vacuum black holes (BHs) may spontaneously grow around the latter, due to a tachyonic instability.
Y. Brihaye, C. Herdeiro, E. Radu
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A symmetry for the cosmological constant [PDF]
Journal of High Energy Physics, 2006 We study a symmetry, schematically Energy -> - Energy, which suppresses matter contributions to the cosmological constant. The requisite negative energy fluctuations are identified with a "ghost" copy of the Standard Model. Gravity explicitly, but weakly, violates the symmetry, and naturalness requires General Relativity to break down at short ...
Kaplan, David E., Sundrum, Raman
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