Results 41 to 50 of about 197,812 (267)

Gravitational Collapse and Cosmological Constant [PDF]

, 2000
We consider here the effects of a non-vanishing cosmological term on the final fate of a spherical inhomogeneous collapsing dust cloud. It is shown that depending on the nature of the initial data from which the collapse evolves, and for a positive value
A. A. Starobinsky, A. Chamorro, A. Chamorro, A. Krasiński, D. Markovic, G. Lemaître, H. Bondi, I. Zehavi, J. P. Ostriker, J. P. S. Lemos, J. P. S. Lemos, K. Lake, K. Lake, K. Lake, P. S. Joshi, P. S. Joshi, R. C. Tolman, R. Penrose, S. Jhingan, S. Jhingan, S. Jhingan, S. Perlmutter, S. Perlmutter, S. S. Deshingkar, S. S. Deshingkar, S. S. Deshingkar, S. S. Deshingkar, Sergio M. C. V. Goncalves, T. P. Singh, V. Sahni   +29 more
core   +2 more sources

Cosmological constant in spinfoam cosmology [PDF]

Physical Review D, 2011
4 pages, 2 ...
Bianchi, Eugenio, Krajewski, Thomas, Rovelli, Carlo, Vidotto, Francesca   +3 more
openaire   +2 more sources

Explicit construction of Penrose diagrams for black hole to white hole transition with spacelike thin shells

Scientific Reports
In 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, Dejan Stojkovic, Dong-han Yeom   +2 more
doaj   +1 more source

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
doaj   +1 more source

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.
doaj   +1 more source

Cosmological constant, violation of cosmological isotropy and CMB

, 2009
We suggest that the solution to the cosmological vacuum energy puzzle does not require any new field beyond the standard model, but rather can be explained as a result of the interaction of the infrared sector of the effective theory of gravity with ...
, A.A. Starobinsky, Ariel R Zhitnitsky, C.J. Copi, E.C. Thomas, F.K. Hansen, F.R. Klinkhamer, F.R. Urban, F.R. Urban, Federico R Urban, J. Bjorken, J.D. Bjorken, N.J. Cornish, Supernova Cosmology Project collaboration, Supernova Search Team collaboration, WMAP collaboration, Y.B. Zeldovich, Y.B. Zeldovich   +17 more
core   +1 more source

Photon‐Sphere Modes in Curved Optical Microcavities: A Black‐Hole Analogue Laser

Advanced Science, EarlyView.
An optical analogue of a Schwarzschild black hole is realized using curved microcavities that preserve light‐like geodesics. A new family of laser modes confined around the photon sphere is identified alongside conventional whispering‐gallery modes. Analytical theory, numerical simulations, and experiments reveal curvature‐induced confinement, enabling
Chenni Xu, Aswathy Sundaresan, Nazire‐Begüm Kazkal, Clement Lafargue, Lior Zarfaty, Li‐Gang Wang, Ofek Birnholtz, Dominique Decanini, Melanie Lebental, Patrick Sebbah   +9 more
wiley   +1 more source

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, Chung-Chi Lee, Kaituo Zhang   +2 more
doaj   +1 more source

‘Turkeys Cannot Vote for Christmas’: Why Epistemic Disobedience in an Anti‐Black World Matters

Australian Journal of Social Issues, EarlyView.
ABSTRACT Never in the history of global coloniality has the idea of epistemic disobedience been as important as in the 21st century. This is not only because the struggle for decolonisation has shifted from physical confrontation between the coloniser and the colonised into a battle of ideas but also because the former has deployed the idea of ...
Morgan Ndlovu
wiley   +1 more source

Cosmological constant as an integration constant

European Physical Journal C: Particles and Fields
The discrepancy between the observed value of the cosmological constant (CC) and its expected value from quantum field theoretical considerations motivates the search for a theory in which the CC is decoupled from the vacuum energy.
Justin C. Feng, Pisin Chen
doaj   +1 more source