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Full-Text Articles in Cosmology, Relativity, and Gravity

Conformal Tensors Via Lovelock Gravity, David Kastor Sep 2013

Conformal Tensors Via Lovelock Gravity, David Kastor

David Kastor

Constructs from conformal geometry are important in low dimensional gravity models, while in higher dimensions the higher curvature interactions of Lovelock gravity are similarly prominent. Considering conformal invariance in the context of Lovelock gravity leads to natural, higher-curvature generalizations of the Weyl, Schouten, Cotton and Bach tensors, with properties that straightforwardly extend those of their familiar counterparts. As a first application, we introduce a new set of conformally invariant gravity theories in D=4k dimensions, based on the squares of the higher curvature Weyl tensors.


Measurement Of Spin-Orbit Misalignment And Nodal Precession For The Planet Around Pre-Main-Sequence Star Ptfo 8-8695 From Gravity Darkening, Jason W. Barnes, Julian C. Van Eyken, Brian K. Jackson, David R. Ciardi, Jonathan J. Fortney Sep 2013

Measurement Of Spin-Orbit Misalignment And Nodal Precession For The Planet Around Pre-Main-Sequence Star Ptfo 8-8695 From Gravity Darkening, Jason W. Barnes, Julian C. Van Eyken, Brian K. Jackson, David R. Ciardi, Jonathan J. Fortney

Brian Jackson

PTFO 8-8695b represents the first transiting exoplanet candidate orbiting a pre-main-sequence star (van Eyken et al. 2012, ApJ, 755, 42). We find that the unusual lightcurve shapes of PTFO 8-8695 can be explained by transits of a planet across an oblate, gravity-darkened stellar disk. We develop a theoretical framework for understanding precession of a planetary orbit’s ascending node for the case when the stellar rotational angular momentum and the planetary orbital angular momentum are comparable in magnitude. We then implement those ideas to simultaneously and self-consistently fit two separate lightcurves observed in 2009 December and 2010 December. Our two self-consistent …


On The Universality Of Inner Black Hole Mechanics And Higher Curvature Gravity, Alejandra Castro, Nima Dehmami, Gaston Giribet, David Kastor Jul 2013

On The Universality Of Inner Black Hole Mechanics And Higher Curvature Gravity, Alejandra Castro, Nima Dehmami, Gaston Giribet, David Kastor

David Kastor

Black holes are famous for their universal behavior. New thermodynamic relations have been found recently for the product of gravitational entropies over all the horizons of a given stationary black hole. This product has been found to be independent of the mass for all such solutions of Einstein-Maxwell theory in d=4,5. We study the universality of this mass independence by introducing a number of possible higher curvature corrections to the gravitational action. We consider finite temperature black holes with both asymptotically flat and (A)dS boundary conditions. Although we find examples for which mass independence of the horizon entropy product continues …


Gravitational Tension And Thermodynamics Of Planar Ads Spacetimes, Basem M. El-Menoufi, Benjamin Ett, David Kastor, Jennie Traschen Jun 2013

Gravitational Tension And Thermodynamics Of Planar Ads Spacetimes, Basem M. El-Menoufi, Benjamin Ett, David Kastor, Jennie Traschen

David Kastor

We derive new thermodynamic relations for asymptotically planar AdS black hole and soliton solutions. In addition to the ADM mass, these spacetimes are characterized by gravitational tensions in each of the planar spatial directions. We show that with planar AdS asymptotics, the sum of the ADM mass and tensions necessarily vanishes, as one would expect from the AdS /CFT correspondence. Each Killing vector of such a spacetime leads to a Smarr formula relating the ADM mass and tensions, the black hole horizon and soliton bubble areas, and a set of thermodynamic volumes that arise due to the non-vanishing cosmological constant. …


Thermodynamic Volumes And Isoperimetric Inequalities For De Sitter Black Holes, Brian P. Dolan, David Kastor, David KubiznˇA´K, Robert B. Mann, Jennie Traschen May 2013

Thermodynamic Volumes And Isoperimetric Inequalities For De Sitter Black Holes, Brian P. Dolan, David Kastor, David KubiznˇA´K, Robert B. Mann, Jennie Traschen

David Kastor

We consider the thermodynamics of rotating and charged asymptotically de Sitter black holes. Using Hamiltonian perturbation theory techniques, we derive three different first law relations including variations in the cosmological constant, and associated Smarr formulas that are satisfied by such spacetimes. Each first law introduces a different thermodynamic volume conjugate to the cosmological constant. We examine the relation between these thermodynamic volumes and associated geometric volumes in a number of examples, including Kerr-dS black holes in all dimensions and Kerr-Newman-dS black holes in D=4. We also show that the Chong-Cvetic-Lu-Pope solution of D=5 minimal supergravity, analytically continued to positive cosmological …


Transformation Of Co-Ordinates And Time At Movement On Inertia Regarding Absolute Outer Space, Vildyan Shavkyatovich Yanbikov Jan 2013

Transformation Of Co-Ordinates And Time At Movement On Inertia Regarding Absolute Outer Space, Vildyan Shavkyatovich Yanbikov

Vildyan Shavkyatovich Yanbikov

In presented research attempt is undertaken to rescue hypothesis of the world broadcast of filling all outer space. One of methods of check of existence of the world broadcast would be speed measurement regarding the world broadcast in driven system of readout. After theoretical research description of optics is given of enabling to measure speed and the direction of movement of inertial reference system regarding absolute outer space . The action concept of optics is based on phenomenon of stellar aberration.


A Lagrangian Which Mathematically Models Lambda Cdm Cosmology And Explains The Null Results Of Dark Astroparticle Searches., Hontas Farmer Dec 2012

A Lagrangian Which Mathematically Models Lambda Cdm Cosmology And Explains The Null Results Of Dark Astroparticle Searches., Hontas Farmer

Hontas F Farmer

Background: The Lambda CDM model or is the standard model of modern cosmology. It is named for dark energy and cold dark matter. This model contains a number of separate components with different mathematical formulations. Strong observational evidence for dark matter has been found by astronomy. At the same time astroparticle physics observations have not found solid evidence of dark matter. Purpose: The purpose of this paper is to reconcile observations of dark matter effects on the galactic and cosmological scales with the null results of astroparticle physics observations such as CDMS and ANTARES. This paper will also provide a …


Gravity And Universe, Vildyan Shavkyatovich Yanbikov Dec 2012

Gravity And Universe, Vildyan Shavkyatovich Yanbikov

Vildyan Shavkyatovich Yanbikov

In the proposed study shows phenomenological model shielding gravitational fields of the protons of the cosmos. The screening of gravity in space is based on the principle that any elementary particle with the mass of rest and located in the free the fall of escapes all gravitational fields in which it is located. The study determined the intensity of the gravitational field of the infinite space half-space. Determined by the effective cross-section proton screening the gravitational field of the cosmos. Defined radius the action of gravitational forces in the cosmos. A formula is obtained which determines the distance to the …