Results 31 to 40 of about 3,462 (164)

Cosmological Implications of the Extended Uncertainty Principle: Energy Conditions, Stability, and Late-time Acceleration

The Astrophysical Journal
We study the cosmological consequences of the extended uncertainty principle (EUP) by deriving modified Friedmann equations through thermodynamic arguments.
M. Roushan, N. Rashidi
doaj   +1 more source

Dynamical Analysis of Scalar Field Cosmologies with Spatial Curvature

The Open Journal of Astrophysics, 2016
We explore the dynamical behaviour of cosmological models involving a scalar field (with an exponential potential and a canonical kinetic term) and a matter fluid with spatial curvature included in the equations of motion.
Mateja Gosenca, Peter Coles
doaj   +1 more source

Constraining on the non-standard cosmological models combining the observations of high-redshift quasars and BAO

European Physical Journal C: Particles and Fields
In this work, we studied four types of cosmological models with different mechanisms driving the accelerated expansion of the universe, include Braneworld models, Chaplygin Gas models, Emergent Dark Energy models, and cosmological torsion models ...
Ziqiang Liu, Tonghua Liu, Xinyi Zhong, Yifei Xu, Xiaogang Zheng   +4 more
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Streamlined supergravity

Journal of High Energy Physics
The textbook N=1 supergravity has an F-term potential depending on a superpotential W (z i ) and a Kähler potential K z i z ¯ i ¯ $$ K\left({z}^i,{\overline{z}}^{\overline{i}}\right) $$ , with the scalar potential V z i z ¯ i ¯ $$ V\left({z}^i,{\overline{
Renata Kallosh, Andrei Linde
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Observações sobre as soluções clássicas da equação de Friedmann

Revista Brasileira de Ensino de Física
As representações gráficas dos modelos clássicos de Friedmann frequentemente induzem ao erro, na discussão das idades dos universos-modelo. A maioria dos livros ignora as diferentes conceituais das representações no que diz respeito a estas idades ...
Arthur Viglioni, Domingos Soares
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w=−1 as an Attractor

The Open Journal of Astrophysics, 2016
It has recently been shown, in flat Robertson-Walker geometries, that the dynamics of gravitational actions which are minimally coupled to matter fields leads to the appearance of “attractors” - sets of physical observables on which phase space measures ...
David Sloan
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Quantum cosmological metroland model [PDF]

Classical and Quantum Gravity, 2010
Relational particle mechanics is useful for modelling whole-universe issues such as quantum cosmology or the problem of time in quantum gravity, including some aspects outside the reach of comparably complex minisuperspace models. In this article, we consider the mechanics of pure shape and not scale of 4 particles on a line, so that the only ...
Anderson, E., Franzen, A.T.
openaire   +3 more sources

Cosmic Chronometers, Pantheon+ Supernovae, and Quasars Favor Coasting Cosmologies over the Flat ΛCDM Model

The Astrophysical Journal
We test and compare coasting cosmological models with curvature parameters $k=\left\{-1,0,+1\right\}$ in ${H}_{0}^{2}{c}^{-2}$ units and the flat ΛCDM model by fitting them to cosmic chronometers (CCs), the Pantheon+ sample of Type Ia supernovae (SNe ...
Peter Raffai, Adrienn Pataki, Rebeka L. Böttger, Alexandra Karsai, Gergely Dálya   +4 more
doaj   +1 more source

Using entropy bounds to avoid the cosmological singularity and constrain cosmological particle production

European Physical Journal C: Particles and Fields, 2023
In this work, we study the applications of entropy bounds in two toy cosmological models with particle production (annihilation), i.e., a radiation-dominated universe and a dust-dominated universe.
Hao Yu, Jin Li
doaj   +1 more source

Polynomial Affine Model of Gravity: After 10 Years

Universe
The polynomial affine model of gravity was proposed as an alternative to metric and metric-affine gravitational models. What, in the beginning, was thought to be a source of unpredictability—the presence of many terms in the action—turned out to be a ...
Oscar Castillo-Felisola, Bastian Grez, Manuel Morocho-López, Jose Perdiguero, Aureliano Skirzewski, Jefferson Vaca-Santana, Nicolas Zambra-Gómez   +6 more
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