Results 41 to 50 of about 310,031 (299)
Cosmological perturbations on local systems [PDF]
, 2006 We study the effect of cosmological expansion on orbits--galactic, planetary, or atomic--subject to an inverse-square force law. We obtain the laws of motion for gravitational or electrical interactions from general relativity--in particular, we find the
A. Krasiński +15 more
core +2 more sources
Zeitschrift für Naturforschung A, 2022 AbstractWe give an introduction into quantum cosmology with emphasis on its conceptual parts. After a general motivation, we review the formalism of canonical quantum gravity on which discussions of quantum cosmology are usually based. We then present the minisuperspace Wheeler–DeWitt equation and elaborate on the problem of time, the imposition of ...
Kiefer, Claus, Sandhoefer, Barbara
openaire +2 more sources
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
doaj +1 more source
Dark matter from torsion in Friedmann cosmology
European Physical Journal C: Particles and Fields, 2022 A cosmological model in an Einstein–Cartan framework endowed with torsion is studied. For a torsion function assumed to be proportional to Hubble expansion function, namely $$\phi =-\alpha H$$ ϕ = - α H , the contribution of torsion function as a dark ...
S. H. Pereira +3 more
doaj +1 more source
Covariant entropy conjecture and concordance cosmological models
, 2008 Recently a covariant entropy conjecture has been proposed for dynamical horizons. We apply this conjecture to concordance cosmological models, namely, those cosmological models filled with perfect fluids, in the presence of a positive cosmological ...
Ashtekar A +11 more
core +1 more source
, 2006 The formalism of rainbow gravity is studied in a cosmological setting. We consider the very early universe which is radiation dominated. A novel treatment in our paper is to look for an ``averaged'' cosmological metric probed by radiation particles ...
Alexander S Magueijo J +8 more
core +2 more sources
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 +9 more
wiley +1 more source
Producing a Scale-Invariant Spectrum of Perturbations in a Hagedorn Phase of String Cosmology
, 2005 We study the generation of cosmological perturbations during the Hagedorn phase of string gas cosmology. Using tools of string thermodynamics we provide indications that it may be possible to obtain a nearly scale-invariant spectrum of cosmological ...
A. Linde +12 more
core +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
The FAST Project - A Next Generation UHECR Observatory
EPJ Web of Conferences, 2017 We present a concept for large-area, low-cost detection of ultrahigh-energy cosmic rays (UHECRs) with a Fluorescence detector Array of Single-pixel Telescopes (FAST)b, addressing the requirements for the next generation of UHECR experiments.
Fujii Toshihiro +15 more
doaj +1 more source