Results 51 to 60 of about 1,644,024 (262)
European Physical Journal C: Particles and Fields, 2019 The future space-borne detectors will provide the possibility to detect gravitational waves emitted from extreme mass ratio inspirals of stellar-mass compact objects into supermassive black holes.
Yu-Peng Zhang +4 more
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Origin of the cosmological constant [PDF]
Astrophysics and Space Science, 2019 The observed value of the cosmological constant corresponds to a time scale that is very close to the current conformal age of the universe. Here we show that this is not a coincidence but is caused by a periodic boundary condition, which only manifests itself when the metric is represented in Euclidian spacetime. The circular property of the metric in
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A natural cosmological constant from chameleons
Physics Letters B, 2015 We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru–Kallosh–Linde–Trivedi (KKLT)-inspired form of the potential and a particular chameleon coupling to the local density, patches of ...
Horatiu Nastase, Amanda Weltman
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REMARKS ON THE COSMOLOGICAL CONSTANT [PDF]
Modern Physics Letters A, 2013 The acceleration of the surface of last scatter (SLS) must somehow reflect the energy content within it. A test particle at the SLS is assumed to experience a linear combination of two forces: one Newtonian, the other pseudo-Newtonian describable by a cosmological constant Λ in general relativity.
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DECOHERENCE IN QUANTUM COSMOLOGY AND THE COSMOLOGICAL CONSTANT [PDF]
Modern Physics Letters A, 2013 We discuss a spacetime having the topology of S3×ℝ but with a different smoothness structure. The initial state of the cosmos in our model is identified with a wildly embedded 3-sphere (or a fractal space). In previous work we showed that a wild embedding is obtained by a quantization of a usual (or tame) embedding.
Asselmeyer-Maluga, T., Krol, J.
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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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Running cosmological constant with observational tests
Physics Letters B, 2016 We investigate the running cosmological constant model with dark energy linearly proportional to the Hubble parameter, Λ=σH+Λ0, in which the ΛCDM limit is recovered by taking σ=0. We derive the linear perturbation equations of gravity under the Friedmann–
Chao-Qiang Geng +2 more
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The history of the Cosmos: Implications for the Hubble tension
Open Astronomy, 2023 In 2007, Storti predicted that the value of the cosmic microwave background radiation (CMBR) temperature may be improved: from the particle data group (PDG) value of [T 0 = 2.725 ± 0.001 K] to [T 0 = 2.7254 K].
Storti Riccardo C.
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Programmable Sequential 4D Actuation in Multistable Kirigami Metamaterials
Advanced Science, EarlyView.This study presents a modular kirigami metamaterial framework enabling programmable multistability and sequential 4D actuation. By coupling geometry‐controlled multistability with material‐dependent recovery kinetics, spatiotemporal deformation can be precisely programmed.
Eui‐Hyun Kim +3 more
wiley +1 more source
Supernovae data: Cosmological Constant or ruling out the Cosmological Principle ?
, 2000 4 LaTex pagesAnalysed in the framework of homogeneous FLRW models, the magnitude-redshift data from high redshift supernovae yield, as a primary result, a strictly positive cosmological constant.
Célérier, Marie-Noëlle
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