Results 91 to 100 of about 51,813 (205)

Emergent Horizons in the Laboratory

, 2010
The concept of a horizon known from general relativity describes the loss of causal connection and can be applied to non-gravitational scenarios such as out-of-equilibrium condensed-matter systems in the laboratory.
Barcelo C, Barcelo C, Barceló C, Birrell N D, Fulling S A, Gullstrand A, Lemaître G, Misner C M, Painlevé P, Queisser F, Ralf Schützhold, Retzker A Cirac J I Plenio M B Reznik B, Schützhold R, Schützhold R Uhlmann M, Uhlmann M, Volovik G E   +15 more
core   +1 more source

Complex degenerate metrics in general relativity: a covariant extension of the Moore–Penrose algorithm

European Physical Journal C: Particles and Fields
The Moore–Penrose algorithm provides a generalized notion of an inverse, applicable to degenerate matrices. In this paper, we introduce a covariant extension of the Moore–Penrose method that permits to deal with general relativity involving complex non ...
Arthur Garnier, Emmanuele Battista
doaj   +1 more source

Universal Constants, Standard Models and Fundamental Metrology

, 2009
Taking into account four universal constants, namely the Planck's constant $h$, the velocity of light $c$, the constant of gravitation $G$ and the Boltzmann's constant $k$ leads to structuring theoretical physics in terms of three theories each taking ...
Cohen-Tannoudji, G.
core   +1 more source

An open system approach to gravity

Journal of High Energy Physics
Several major open problems in cosmology — including the nature of inflation, dark matter, and dark energy — share a common structure: they involve spacetime-filling media with unknown microphysics, and can be probed so far only through their ...
Santiago Agüí Salcedo, Thomas Colas, Lennard Dufner, Enrico Pajer   +3 more
doaj   +1 more source

Averaged null energy condition in Loop Quantum Cosmology

, 2008
Wormhole and time machine are very interesting objects in general relativity. However, they need exotic matters which are impossible in classical level to support them.
C. Rovelli, C. Rovelli, H. Casimir, Jian-Yang Zhu, Li-Fang Li, T. Thiemann   +5 more
core   +1 more source

A short introduction to cosmology and its current status

SciPost Physics Lecture Notes
The current cosmological model, known as the $\Lambda$-Cold Dark Matter model (or $\Lambda$CDM for short) is one of the most astonishing accomplishments of contemporary theoretical physics.
Pedro G. Ferreira, Alexander Roskill
doaj   +1 more source

Darkness without dark matter and energy – generalized unimodular gravity

Physics Letters B, 2017
We suggest a Lorentz non-invariant generalization of the unimodular gravity theory, which is classically equivalent to general relativity with a locally inert (devoid of local degrees of freedom) perfect fluid having an equation of state with a constant ...
A.O. Barvinsky, A.Yu. Kamenshchik
doaj   +1 more source

Brane-World Gravity

Living Reviews in Relativity, 2010
The observable universe could be a 1+3-surface (the “brane”) embedded in a 1+3+d-dimensional spacetime (the “bulk”), with Standard Model particles and fields trapped on the brane while gravity is free to access the bulk.
Roy Maartens, Kazuya Koyama
doaj  

Cosmic Inflation, Quantum Information and the Pioneering Role of John S Bell in Cosmology

Universe, 2019
According to the theory of cosmic inflation, the large scale structures observed in our Universe (galaxies, clusters of galaxies, Cosmic Background Microwave—CMB—anisotropy…) are of quantum mechanical origin. They are nothing but vacuum
Jérôme Martin
doaj   +1 more source

Quantum Vibrational Relativity (QVR): A Unified Framework Bridging General Relativity, Quantum Mechanics, and Cosmology

Quantum Vibrational Relativity (QVR) - Version 2.0 Overview: A scalar-field extension of General Relativity in which a single k-essence field with conformal coupling to matter replaces both dark matter particles and a separate cosmological constant.
openaire   +1 more source