Zobrazeno 1 - 10
of 221 641
pro vyhledávání: '"Friedmann A"'
Autor:
Matone, Marco, Dimakis, Nikolaos
In this work, we demonstrate that the recently introduced linear form of the Friedmann equations corresponds to the first-order WKB expansion of a quantum cosmological equation, indicating that both General Relativity (GR) contains aspects of Quantum
Externí odkaz:
http://arxiv.org/abs/2411.07961
Autor:
Herrera, Ramon, Rios, Carlos
The reconstruction of an inflationary universe considering the parametrization of the scalar spectral index as a function of the number of $e-$folds in the framework of a modified Friedmann equation is analyzed. In this context, we examine the possib
Externí odkaz:
http://arxiv.org/abs/2409.06844
Autor:
Nakamura, Makoto, Yoshizumi, Takuma
The Cauchy problem for semi-linear Klein-Gordon equations is considered in Friedmann-Lema\^itre-Robertson-Walker spacetimes. The local and global well-posedness of the Cauchy problem is considered in Sobolev spaces. The non-existence of global soluti
Externí odkaz:
http://arxiv.org/abs/2411.02872
Autor:
Bronnikov, Kirill A.1,2,3 (AUTHOR) kb20@yandex.ru, Kashargin, Pavel E.4 (AUTHOR) pkashargin@mail.ru, Sushkov, Sergey V.4 (AUTHOR) sergey_sushkov@mail.ru
Publikováno v:
Universe (2218-1997). Nov2023, Vol. 9 Issue 11, p465. 21p.
Autor:
Ökcü, Özgür, Aydiner, Ekrem
Publikováno v:
Gen Relativ Gravit 56 (2024) 87
In this paper, employing the exponential corrected entropy (Chatterjee and Ghosh in Phys Rev Lett 125:041302, 2020), we derive the modified Friedmann equations from the first law of thermodynamics at apparent horizon and Verlinde's entropic gravity s
Externí odkaz:
http://arxiv.org/abs/2407.14685
We extend the earlier linear studies of cosmological peculiar velocities to Friedmann universes with nonzero spatial curvature. In the process, we also compare our results with those obtained in cosmologies with Euclidean spatial sections. Employing
Externí odkaz:
http://arxiv.org/abs/2404.19046
Publikováno v:
Published in Universe, 10 (3) 137 (2024), Special Issue "The Friedmann Cosmology: A Century Later"
We apply a very simple procedure to construct non-singular cosmological models for flat Friedmann universes filled with minimally coupled scalar fields or by tachyon Born-Infeld-type fields. Remarkably, for the minimally coupled scalar field and the
Externí odkaz:
http://arxiv.org/abs/2403.08400
Autor:
Mostepanenko, Vladimir M.
Publikováno v:
Universe, v.10, N2, 84 (2024)
This review devoted to the centenary of Alexander Friedmann's prediction of the Universe expansion presents the results obtained by him in 1922 and 1924 and the sketch of their further developments. Special attention is paid to the role of mathematic
Externí odkaz:
http://arxiv.org/abs/2403.01555
From a fractal perspective, the entropy bound of gravitational systems undergoes changes. Furthermore, in the cosmological setting, the conservation law of a perfect fluid is also altered in such systems, affecting spatial elements like volume, area,
Externí odkaz:
http://arxiv.org/abs/2404.06986
Publikováno v:
Universe 2024, 10(4), 169
Nowadays, at least two relics of the Big Bang have survived - the cosmological microwave background (CMB) and the cosmological neutrino background (C$\nu$B). Being the second most abundant particle in the Universe, the neutrino has a significant impa
Externí odkaz:
http://arxiv.org/abs/2404.07081