Below are a number of articles that MAY discuss related Physics. Pity that most of this info is not only over my head but requires a purchase price that I cannot afford.
Anyone had much experience with these studies to break down the possible physics that might be involved (and do so without as much technical jargon)?
Mass of asymptotically anti-de Sitter hairy spacetimes
Andres Anabalon, Dumitru Astefanesei, Cristian Martinez
(Submitted on 11 Jul 2014)
In the standard asymptotic expansion of four dimensional static asymptotically flat spacetimes, the coefficient of the first subleading term of the lapse function can be identified with the mass of the spacetime. Using the Hamiltonian formalism we show that, in asymptotically locally anti-de Sitter spacetimes endowed with a scalar field, the mass can read off in the same way only when the boundary conditions are compatible with the asymptotic realization of the anti-de Sitter symmetry. In particular, this implies that some prescriptions for computing the mass of a hairy spacetime are not suitable when the scalar field breaks the asymptotic anti-de Sitter invariance.
Journeys through antigravity?
John Joseph M. Carrasco, Wissam Chemissany and Renata Kallosh
Stanford Institute for Theoretical Physics and Department of Physics, Stanford University,
January 23, 2014
Abstract:
A possibility of journeys through antigravity has recently been proposed, with the suggestion that Weyl-invariant extension of scalars coupled to Einstein gravity allows for an unambiguous classical evolution through cosmological singularities in anisotropic spacetimes. We compute the Weyl invariant curvature squared and find that it blows up for the proposed anisotropic solution both at the Big Crunch as well as at the Big Bang. Therefore the cosmological singularities are not resolved by uplifting Einstein theory to a Weyl invariant model
Cosmological Perturbations in Antigravity
Marius Oltean, Robert Brandenberger
(Submitted on 27 Jun 2014 (v1), last revised 28 Jul 2014 (this version, v2))
We compute the evolution of cosmological perturbations in a recently proposed Weyl-symmetric theory of two scalar fields with oppositely-signed conformal couplings to Einstein gravity. It is motivated from the minimal conformal extension of the Standard Model, such that one of these scalar fields is the Higgs while the other is a new particle, the dilaton, introduced to make the Higgs mass conformally symmetric. At the background level, the theory admits novel geodesically-complete cyclic cosmological solutions characterized by a brief period of repulsive gravity, or "antigravity", during each successive transition from a Big Crunch to a Big Bang. We show that despite the necessarily wrong-signed kinetic term of the dilaton in the full action, its cosmological solutions are stable at the perturbative level.
Quantum Entanglement: Where Dark Energy and Negative Gravity plus Accelerated Expansion of the Universe Comes from
Journal of Quantum Information Science
Vol.3 No.2(2013), Article ID:32831,21 pages DOI:10.4236/jqis.2013.32011
Mohamed S. El Naschie
Department of Physics, Alexandria University, Alexandria, Egypt
Abstract:
Dark energy is shown to be the absolute value of the negative kinetic energy of the halo-like quantum wave modeled mathematically by the empty set in a five dimensional Kaluza-Klein (K-K) spacetime. Ordinary or position energy of the particle on the other hand is the dual of dark energy and is contained in the dynamic of the quantum particle modeled by the zero set in the same five dimensional K-K spacetime. The sum of both dark energy of the wave and the ordinary energy of the particle is exactly equal to the energy given by the well known formula of Einstein which is set in a four dimensional spacetime. Various interpretations of the results are presented and discussed based on the three fundamental energy density equations developed. In particular where E is the energy, m is the mass and c is the speed of light, is Hardy’s quantum entanglement and gives results in complete agreement with the cosmological measurements of WMAP and Supernova. On the other hand gives an intuitive explanation of negative gravity and the observed increased rate of cosmic expansion. Adding to one finds which as we mentioned above is Einstein’s famous relativity formula. We conclude that similar to the fact that the quantum wave interpreted generally as probability wave which is devoid of ordinary energy decides upon the location of a quantum particle, it also exerts a negative gravity effect on the cosmic scale of our clopen, i.e. closed and open universe.
Or his work entitled: Pinched Material Einstein Space-Time Produces Accelerated Cosmic ExpansionMapping pure gravity to strings in three-dimensional anti-de Sitter geometry
Bo Sundborg
(Submitted on 31 May 2013)
Strings propagating in three-dimensional anti-de Sitter space with a background antisymmetric tensor field are well understood, even at the quantum level. Pure three-dimensional gravity with a negative cosmological constant is potentially important because of the existence of black hole solutions and an asymptotic conformal symmetry, but it is mysterious and surprisingly resistant to analysis. In this letter, the two theories are related by a map on the classical level. The map is obtained by gauge fixing the string completely, like in a light cone gauge, and comparing the resulting constrained theory with the boundary theory obtained from gravity by imposing the appropriate asymptotic boundary conditions. The two theories are formally related as different gauge fixings of the same gauge theory. Instabilities and (anti)-evaporation of Schwarzschild–de Sitter black holes in modified gravity
Phys. Rev. D 88, 104022 – Published 20 November 2013
L. Sebastiani, D. Momeni, R. Myrzakulov, and S. D. Odintsov
Abstract
We investigate the future evolution of the Nariai black hole, which is the extremal limit of the Schwarzschild–de Sitter one in modified gravity. The perturbation equations around the Nariai black hole are derived in static and cosmological patches for general F(R) gravity. The analytical and numerical study of several realistic F(R) models shows the occurrence of a rich variety of scenarios: instabilities, celebrated Hawking evaporation, and anti-evaporation of black holes. The realization of a specific scenario depends on the model under consideration. It is remarkable that the presence of such primordial black holes in the current Universe may indicate modified gravity, which supports the anti-evaporation as the preferable model. As a generalization, we extend the study of the Nariai black hole evolution to modified Gauss-Bonnet gravity. The corresponding perturbation equations turn out to be much more complicated than in the case of F(R) gravity. For a specific example of modified Gauss-Bonnet gravity, we demonstrate that the Nariai solution may be stable.Accelerating cosmology in modified gravity: From convenient F(R) or string-inspired theory to bimetric F(R) gravity
Shin'ichi Nojiri
Department of Physics, Nagoya University, Nagoya 464-8602, Japan
Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602, Japan
Sergei D. Odintsov
Consejo Superior de Investigaciones Científicas, Institut de Ciencies de l'Espai (ICE), (CSIC-IEEC), Campus UAB, Torre C5-Parell-2a Pl, E-08193 Bellaterra, Barcelona, Spain
Instituciò Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
Tomsk State Pedagogical University, Tomsk 634061, Russia
Published: 27 January 2014
Abstract:
We consider modified gravity which may describe the early-time inflation and/or late-time cosmic acceleration of the universe. In particular, we discuss the properties of F(R), F(G), string-inspired and scalar-Einstein–Gauss–Bonnet gravities, including their FRW equations and fluid or scalar-tensor description. Simplest accelerating cosmologies are investigated and possibility of unified description of the inflation with dark energy is described. The cosmological reconstruction program which permits to get the requested universe evolution from modified gravity is developed. As some extension, massive F(R) bigravity which is ghost-free theory is presented. Its scalar-tensor form turns out to be the easiest formulation. The cosmological reconstruction method for such bigravity is presented. The unified description of inflation with dark energy in F(R) bigravity turns out to be possible.
Anti–de Sitter holography for gravity and higher spin theories in two dimensions
Phys. Rev. D 89, 044001 – Published 5 February 2014
Daniel Grumiller, Mauricio Leston, and Dmitri Vassilevich
Abstract
We provide a holographic description of two-dimensional dilaton gravity with anti–de Sitter boundary conditions. We find that the asymptotic symmetry algebra consists of a single copy of the Virasoro algebra with nonvanishing central charge and point out difficulties with the standard canonical treatment. We generalize our results to higher spin theories and thus provide the first examples of two-dimensional higher spin gravity with holographic description. For spin-3 gravity we find that the asymptotic symmetry algebra is a single copy of the W3 algebra.
Circular geodesics of naked singularities in the Kehagias-Sfetsos metric of Hořava's gravity
Ronaldo S. S. Vieira, Jan Schee, W\lodek Kluźniak, Zdeněk Stuchlík, Marek Abramowicz
(Submitted on 22 Nov 2013)
We discuss photon and test-particle orbits in the Kehagias-Sfetsos (KS) metric. For any value of the Ho\v{r}ava parameter ω, there are values of the gravitational mass M for which the metric describes a naked singularity, and this is always accompanied by a vacuum "antigravity sphere" on whose surface a test particle can remain at rest (in a zero angular momentum geodesic), and inside which no circular geodesics exist. The observational appearance of an accreting KS naked singularity in a binary system would be that of a quasi-static spherical fluid shell surrounded by an accretion disk, whose properties depend on the value of M, but are always very different from accretion disks familiar from the Kerr-metric solutions. The properties of the corresponding circular orbits are qualitatively similar to those of the Reissner-Nordstr\"om naked singularities. When event horizons are present, the orbits outside the Kehagias-Sfetsos black hole are qualitatively similar to those of the Schwarzschild metric.
