Results 11 to 20 of about 11,149 (268)
Homogeneous cosmologies with a cosmological constant [PDF]
Physical Review D, 1999 Spatially homogeneous cosmological models with a positive cosmological constant are investigated, using dynamical systems methods. We focus on the future evolution of these models. In particular, we address the question whether there are models within this class that are de Sitter-like in the future, but are tilted.
Goliath, Martin, Ellis, George F. R.
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Physical Review Letters, 2007 We explore nonlocally modified models of gravity, inspired by quantum loop corrections, as a mechanism for explaining current cosmic acceleration. These theories enjoy two major advantages: they allow a delayed response to cosmic events, here the transition from radiation to matter dominance, and they avoid the usual level of fine tuning; instead ...
Deser, S., Woodard, R. P.
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Scientific Reports, 2012 Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive.
Krioukov, Dmitri +5 more
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International Journal of Modern Physics D, 1999 The notion of time in cosmology is revealed through an examination of transition matrix elements of radiative processes occurring in the cosmos. To begin with, the very concept of time is delineated in classical physics in terms of correlations between the succession of configurations which describe a process and a standard trajectory called the clock.
Brout, Hyman Robert, Parentani, Renaud
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Geometrothermodynamic Cosmology
Entropy, 2023 We review the main aspects of geometrothermodynamics, a formalism that uses contact geometry and Riemannian geometry to describe the properties of thermodynamic systems. We show how to handle in a geometric way the invariance of classical thermodynamics with respect to Legendre transformations, which means that the properties of the systems do not ...
Orlando Luongo, Hernando Quevedo
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Bootstrapped Newtonian Cosmology and the Cosmological Constant Problem [PDF]
Symmetry, 2021 Bootstrapped Newtonian gravity was developed with the purpose of estimating the impact of quantum physics in the nonlinear regime of the gravitational interaction, akin to corpuscular models of black holes and inflation. In this work, we set the ground for extending the bootstrapped Newtonian picture to cosmological spaces.
Casadio, Roberto, Giusti, Andrea
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International Journal of Modern Physics D, 2012 Using a new effective action predicted from quantum gravity where the sign of the Euclidean Einstein action is reversed, we discuss Wentzel–Kramers–Brillouin (WKB) solutions in quantum cosmology and predict that this sign change might explain the origin of phantom scalars.
Arundhati Dasgupta, Adamantia Zampeli
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International Journal of Modern Physics: Conference Series, 2012 We review the difficulties of the generalized Chaplygin gas model to fit observational data, due to the tension between background and perturbative tests. We argue that such issues may be circumvented by means of a self-interacting scalar field representation of the model.
Julio C. Fabris +4 more
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COSMOLOGICAL ZITTERBEWEGUNG [PDF]
International Journal of Modern Physics D, 2013 We describe a new phenomenon of zitterbewegung of a free Dirac particle in cosmological spacetimes. Unlike the similar effect theorized by Schrödinger in 1930, the cosmological zitterbewegung is a real, physically attainable effect, which originates from the mixing of positive and negative frequency modes of a field operator in cosmological spacetimes.
Girdhar, Parth, Kobakhidze, Archil
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Cosmological Bounce and the Cosmological Constant Problem
SSRN Electronic Journal, 2022 32 pages, 9 ...
Pavlović, Petar, Sossich, Marko
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