Results 21  30
of
215
Dark Energy Simulations
 Physics of the Dark Universe, arXiv:1210.6650
"... Cosmology is presently facing the deep mystery of the origin of the observed accelerated expansion of the Universe. Be it a cosmological constant, a homogeneous scalar field, or a more complex inhomogeneous field possibly inducing effective modifications of the laws of gravity, such elusive physica ..."
Abstract

Cited by 6 (3 self)
 Add to MetaCart
(Show Context)
Cosmology is presently facing the deep mystery of the origin of the observed accelerated expansion of the Universe. Be it a cosmological constant, a homogeneous scalar field, or a more complex inhomogeneous field possibly inducing effective modifications of the laws of gravity, such elusive physical entity is indicated with the general term of “Dark Energy”. The growing role played by numerical Nbody simulations in cosmological studies as a fundamental connection between theoretical modeling and direct observations has led to impressive advancements also in the development and application of specific algorithms designed to probe a wide range of Dark Energy scenarios. Over the last decade, a large number of independent and complementary investigations have been carried out in the field of Dark Energy Nbody simulations, starting from the simplest case of homogeneous Dark Energy models up to the recent development of highly sophisticated iterative solvers for a variety of Modified Gravity theories. In this Review – which is meant to be complementary to the general Review by Kuhlen et al. published in this Volume – I will discuss the range of scenarios for the cosmic acceleration that have been successfully investigated by means of dedicated Nbody simulations, and I will provide a broad summary of the main results that have been obtained in this rather new research field. I will focus the discussion on a few selected studies that have led to particularly significant advancements in the field, and I will provide a comprehensive list of references for a larger number of related works. Due to the vastness of the topic, the discussion will not enter into the finest details of the different implementations and will mainly focus on the outcomes of the various simulations studies. Although quite recent, the field of Dark Energy simulations has witnessed huge developments in the last few years, and presently stands as a reliable approach to the investigation of the fundamental nature of Dark Energy.
Radioscience simulations in General Relativity and in alternative theories of gravity
 Proceedings of the XLVIth Rencontres de Moriond and GPhys Colloquium 2011: Gravitational Waves and Experimental Gravity
, 2011
"... ar ..."
(Show Context)
On the interaction of mesoscopic quantum systems with gravity, Annalen Phys
"... Key words quantum gravity, mesoscopic systems, gravitational waves, quantum fluids, gravitoelectromagnetism. ..."
Abstract

Cited by 4 (0 self)
 Add to MetaCart
(Show Context)
Key words quantum gravity, mesoscopic systems, gravitational waves, quantum fluids, gravitoelectromagnetism.
Pseudoredundant vacuum energy
, 801
"... We discuss models that can account for today’s dark energy. The underlying cosmological constant may be Planck scale but starts as a redundant coupling which can be eliminated by a field redefinition. The observed vacuum energy arises when the redundancy is explicitly broken, say by a nonminimal co ..."
Abstract

Cited by 4 (0 self)
 Add to MetaCart
(Show Context)
We discuss models that can account for today’s dark energy. The underlying cosmological constant may be Planck scale but starts as a redundant coupling which can be eliminated by a field redefinition. The observed vacuum energy arises when the redundancy is explicitly broken, say by a nonminimal coupling to curvature. We give a recipe for constructing models, including R + 1/R type models, that realize this mechanism and satisfy all solar system constraints on gravity. A similar model, based on GaussBonnet gravity, provides a technically natural explanation for dark energy and exhibits an interesting seesaw behavior: a large underlying cosmological constant gives rise to both low and high curvature solutions. Such models could be statistically favored in the string landscape. 1
Higgs production as a probe of chameleon dark energy
 ISSN 15507998. doi: 10.1103/PhysRevD.81.103524. URL http://arxiv.org/abs/ 0911.1267http://link.aps.org/doi/10.1103/PhysRevD.81.103524
, 2010
"... ar ..."
(Show Context)
The experimental status of special and general relativity. Handbook of Spacetime
, 2013
"... ar ..."
(Show Context)
Reflections on Gravity ∗
, 2008
"... A pedagogical description of a simple ungeometrical approach to General Relativity is given, which follows the pattern of well understood field theories, such as electrodynamics. This leads quickly to most of the important weak field predictions, as well as to the radiation damping of binary pulsars ..."
Abstract

Cited by 3 (0 self)
 Add to MetaCart
(Show Context)
A pedagogical description of a simple ungeometrical approach to General Relativity is given, which follows the pattern of well understood field theories, such as electrodynamics. This leads quickly to most of the important weak field predictions, as well as to the radiation damping of binary pulsars. Moreover, certain consistency arguments imply that the theory has to be generally invariant, and therefore one is bound to end up with Einstein’s field equations. Although this field theoretic approach, which has been advocated repeatedly by a number of authors, starts with a spin2 theory on Minkowski spacetime, it turns out in the end that the flat metric is actually unobservable, and that the physical metric is curved and dynamical. Short sections are devoted to tensorscalar generalizations, the mystery of the vacuum energy density, and quintessence. 1 Introductory Remarks
Search for Gravitational Wave Bursts from Soft Gamma Repeaters
, 2008
"... We present the results of a LIGO search for shortduration gravitational waves associated with soft gamma repeater (SGR) bursts, and a method for calibrating gravitational wave detectors via photon actuators. Photon calibrators provide an independent calibration of LIGO’s three gravitational wave de ..."
Abstract

Cited by 3 (1 self)
 Add to MetaCart
(Show Context)
We present the results of a LIGO search for shortduration gravitational waves associated with soft gamma repeater (SGR) bursts, and a method for calibrating gravitational wave detectors via photon actuators. Photon calibrators provide an independent calibration of LIGO’s three gravitational wave detectors. Their nominal 2σ confidence error bars are currently estimated to be ∼3%. The photon calibrators have provided a valuable check on the official calibration, uncovering problems that may otherwise have gone unnoticed. We also present the first gravitational wave search sensitive to neutron star fmodes, usually considered the most efficient gravitational wave emitting modes. We find no evidence of gravitational waves associated with any SGR burst in a sample consisting of the 2004 December 27 giant flare from SGR 1806−20 and 190 lesser events from SGR 1806−20 and SGR 1900+14 which occurred during the first year of LIGO’s fifth science run. Gravitational wave strain upper limits and modeldependent gravitational wave emission energy upper limits are estimated for individual bursts using a variety of simulated waveforms. The unprecedented sensitivity of the detectors allows us to set the most stringent limits on transient gravitational wave amplitudes
The Gaia Mission and the Asteroids, in
 Lecture Notes in Physics, Berlin
"... A perspective from space astrometry and photometry for asteroids studies and science. ..."
Abstract

Cited by 3 (0 self)
 Add to MetaCart
(Show Context)
A perspective from space astrometry and photometry for asteroids studies and science.