Results 61 to 70 of about 7,599,029 (258)
Physics Letters BThe (old) cosmological constant problem consists of two different problems. The first is the huge discrepancy between the value of the cosmological constant deduced from observations and its value expected from cosmological constant-like theoretical ...
Recai Erdem
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Semi-classical gravity in de Sitter spacetime and the cosmological constant
Physics Letters B, 2019 We show that there exist solutions to the semi-classical gravity equations in de Sitter spacetime sourced by the renormalised stress-energy tensor of a free Klein-Gordon field.
Benito A. Juárez-Aubry
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Revising the cosmological constant problem through a fluid different from the quintessence
Physical Sciences and Technology, 2022 The role of a scalar field is reexamined through the introduction of a quasi-quintessence model. Unlike quintessence, in the quasi-quintessence model, the pressure of the scalar field does not depend on its kinetic energy. This research note provides an
Orlando Luongo
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, 2020 Supplementary Mathematica script for article "A Solution to the Cosmological Constant Problem in Two Time Dimensions" to calculate Christoffel symbols, Ricci tensor and scalar and to solve equations for the cosmological ...
Christoph Köhn
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Environmental selection of the cosmological constant and electroweak scales
Journal of High Energy Physics, 2022 We investigate whether selfish/Goldilocks Higgs models can be extended to accomodate vacua with both the right Higgs mass and cosmological constant. Through the introduction of multiple four-form fields coupled with the Higgs scalar boson we find that ...
Matteo Moretti, Francisco G. Pedro
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Constraining the Swiss-Cheese IR-Fixed Point Cosmology with Cosmic Expansion
Universe, 2021 A recent work proposed that the recent cosmic passage to a cosmic acceleration era is the result of the existence of small anti-gravity sources in each galaxy and clusters of galaxies. In particular, a Swiss-cheese cosmology model, which relativistically
Ayan Mitra +4 more
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Exacerbating the Cosmological Constant Problem with Interacting Dark Energy Models. [PDF]
Physical Review Letters, 2016 Future cosmological surveys will probe the expansion history of the Universe and constrain phenomenological models of dark energy. Such models do not address the fine-tuning problem of the vacuum energy, i.e., the cosmological constant problem (CCP), but
M. C. David Marsh
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On the cosmological constant problem
Physics Letters B, 1984 Abstract We prove that Weyl invariant theories of gravity possess a remarkable property which, under very general assumptions, explains the stability of flat space-time. We show explicitly how conformal invariance is broken spontaneously by the vacuum expectation value of an unphysical scalar field; this process induces general relativity as an ...
I. Antoniadis, N.C. Tsamis
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Cosmological constant problems and the renormalization group [PDF]
Journal of Physics A: Mathematical and Theoretical, 2007 The Cosmological Constant Problem emerges when Quantum Field Theory is applied to the gravitational theory, due to the enormous magnitude of the induced energy of the vacuum. The unique known solution of this problem involves an extremely precise fine-tuning of the vacuum counterpart.
Shapiro, Ilya L., Sola, Joan
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Scientific ReportsIn this article, we explicitly construct the coordinates associated with the Penrose diagram in spacetimes connected via a spacelike thin shell in the following two examples: the generalized black-to-white hole bounce with mass difference and the ...
Wei-Chen Lin +2 more
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