Zobrazeno 1 - 10
of 652
pro vyhledávání: '"Hubble volume"'
Autor:
Christopher Pilot
Publikováno v:
International Journal of Astronomy and Astrophysics. 11:265-278
Assuming a geometrically closed universe, we predict a value for the cosmic curvature, , a value within current observational bounds. We also propose a thermodynamic heat engine model for the universe, which bypasses the need for an inflaton field. O
Autor:
Neil deGrasse Tyson
Publikováno v:
A Brief Welcome to the Universe
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::a12358025c23844e528c8aca0e328832
https://doi.org/10.1515/9780691223612-002
https://doi.org/10.1515/9780691223612-002
Autor:
M. Vijaya Santhi, Y. Sobhanbabu
Publikováno v:
European Physical Journal
European Physical Journal C: Particles and Fields, Vol 81, Iss 11, Pp 1-10 (2021)
European Physical Journal C: Particles and Fields, Vol 81, Iss 11, Pp 1-10 (2021)
In this work devoted to the investigation of the Tsallis holographic dark energy (IR cut-off is Hubble radius) in homogeneous and anisotropic Kantowski–Sachs Universe within the frame-work of Saez–Ballester scalar tensor theory of gravitation. We
Publikováno v:
Digital.CSIC. Repositorio Institucional del CSIC
instname
instname
We propose a cosmological scenario in which the universe undergoes through a non-singular bounce, and after the bounce, it decelerates having a matter-like dominated evolution during some regime of the deceleration era, and finally at the present epo
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3a4fba1c0eb51bdeb4e2f3ddf2da0148
http://hdl.handle.net/10261/262545
http://hdl.handle.net/10261/262545
Cosmological perturbations for ultralight axionlike particles in a state of Bose-Einstein condensate
Autor:
Shinji Tsujikawa
Publikováno v:
Physical Review D. 103
For ultra-light scalar particles like axions, dark matter can form a state of the Bose-Einstein condensate (BEC) with a coherent classical wave whose wavelength is of order galactic scales. In the context of an oscillating scalar field with mass $m$,
Publikováno v:
Journal of High Energy Physics, vol 2021, iss 6
Journal of High Energy Physics, Vol 2021, Iss 6, Pp 1-42 (2021)
Journal of High Energy Physics
Journal of High Energy Physics, Vol 2021, Iss 6, Pp 1-42 (2021)
Journal of High Energy Physics
We explore the cosmological consequences of the superconductivity of QCD axion strings. Axion strings can support a sizeable chiral electric current and charge, which alters their early universe dynamics. Shrinking axion string loops can become effec
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f74e2deed205abf90d0d9a864c80d9b4
https://escholarship.org/uc/item/7cz674sp
https://escholarship.org/uc/item/7cz674sp
Autor:
Anna Ijjas, Roman Kolevatov
Publikováno v:
Physical Review D. 103
In this Letter, we describe how a spectrum of entropic perturbations generated during a period of slow contraction can source a nearly scale-invariant spectrum of curvature perturbations on length scales larger than the Hubble radius during the trans
Autor:
Ken D. Olum, Eleni-Alexandra Kontou
Publikováno v:
Journal of Cosmology and Astroparticle Physics, 2021(3):097. IOP Publishing Ltd.
Eternal inflation requires upward fluctuations of the energy in a Hubble volume, which appear to violate the energy conditions. In particular, a scalar field in an inflating spacetime should obey the averaged null energy condition, which seems to rul
Publikováno v:
European Physical Journal C: Particles and Fields, Vol 79, Iss 6, Pp 1-11 (2019)
European Physical Journal
European Physical Journal
We examine the evolution of non-relativistic cold dark matter gravitationally coupled to baryons with modes deep inside the Hubble radius (sub-horizon regime) using akinetic theory approach within the realm of Newtonian theory. We obtain the general
Autor:
S. Ghaffari
Publikováno v:
New Astronomy. 67:76-84
We study the cosmological dynamics of holographic dark energy in a DGP braneworld in which the holographic parameter c2 is slowly varying with time. In our model, two famous IR cutoffs including the Hubble radius and the Granda–Oliveros cutoffs are