scholarly journals Gravitational waves generated during inflation from a 5D vacuum theory of gravity in a de Sitter expansion

2007 ◽  
Vol 645 (1) ◽  
pp. 6-11 ◽  
Author(s):  
José Edgar Madriz Aguilar
Keyword(s):  
Gravitational Waves ◽  
De Sitter ◽  
Theory Of Gravity ◽  
Vacuum Theory

scholarly journals Gravitational waves during inflation in presence of a decaying cosmological parameter from a 5D vacuum theory of gravity

2007 ◽  
Vol 649 (5-6) ◽  
pp. 343-348 ◽  
Author(s):  
Silvina Paola Gomez Martínez ◽  
José Edgar Madriz Aguilar ◽  
Mauricio Bellini
Keyword(s):  
Gravitational Waves ◽  
Cosmological Parameter ◽  
Theory Of Gravity ◽  
Vacuum Theory

scholarly journals Hamiltonian charges in the asymptotically de Sitter spacetimes

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Maciej Kolanowski ◽  
Jerzy Lewandowski
Keyword(s):  
Phase Space ◽  
Initial Data ◽  
Exact Solutions ◽  
Gravitational Waves ◽  
Physical Meaning ◽  
De Sitter ◽  
Killing Vectors ◽  
Asymptotically Flat ◽  
Angular Momenta ◽  
The One

Abstract We generalize a notion of ‘conserved’ charges given by Wald and Zoupas to the asymptotically de Sitter spacetimes. Surprisingly, our construction is less ambiguous than the one encountered in the asymptotically flat context. An expansion around exact solutions possessing Killing vectors provides their physical meaning. In particular, we discuss a question of how to define energy and angular momenta of gravitational waves propagating on Kottler and Carter backgrounds. We show that obtained expressions have a correct limit as Λ → 0. We also comment on the relation between this approach and the one based on the canonical phase space of initial data at ℐ+.

scholarly journals What are the wild waves saying? Yet another meditation on the predictions, searches for, and detections of gravitational waves

2018 ◽  
Vol 27 (14) ◽  
pp. 1830009
Author(s):  
Virginia Trimble
Keyword(s):  
General Relativity ◽  
Gravitational Waves ◽  
Point Of View ◽  
Large Majority ◽  
Laboratory Apparatus ◽  
New Information ◽  
Theory Of Gravity ◽  
To Come ◽  
The Universe

A large majority of the physics and astronomy communities are now sure that gravitational waves exist, can be looked for, and can be studied via their effects on laboratory apparatus as well as on astronomical objects. So far, everything found out has agreed with the predictions of general relativity, but hopes are high for new information about the universe and its contents and perhaps for hints of a better theory of gravity than general relativity (which even Einstein expected to come eventually). This is one version of the story, from 1905 to the present, told from an unusual point of view, because the author was, for 28.5 years, married to Joseph Weber, who built the first detectors starting in the early 1960s and operated one or more until his death on 30 September 2000.

scholarly journals De Sitter braneworld and gravitational waves

2021 ◽  
Author(s):  
Dong-Yu Li ◽  
Zhao-Xiang Wu ◽  
Hao Hu ◽  
Bao-Min Gu
Keyword(s):  
Gravitational Waves ◽  
Scalar Fields ◽  
Background Solution ◽  
De Sitter ◽  
Dimensional Theory ◽  
Massive Mode ◽  
Large Extra Dimension ◽  
Mass Gap ◽  
Massless Mode ◽  
Background Fields

We study the braneworld theory constructed by multi scalar fields. The model contains a smooth and infinitely large extra dimension, allowing the background fields propagating in it. We give a de Sitter solution for the four-dimensional cosmology as a good approximation to the early universe inflation. We show that the graviton has a localizable massless mode, and a series of continuous massive modes, separated by a mass gap. There could be a normalizable massive mode, depending on the background solution. The gravitational waves of massless mode evolve the same as the four dimensional theory, while that of the massive modes evolve greatly different from the massless mode.

scholarly journals Gravitational waves in a spatially closed de Sitter spacetime

2013 ◽  
Vol 73 (10) ◽  
Author(s):  
Amir H. Abbassi ◽  
J. Khodagholizadeh ◽  
Amir M. Abbassi
Keyword(s):  
Gravitational Waves ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Sitter Spacetime

scholarly journals A CHERN–SIMONS E8 GAUGE THEORY OF GRAVITY IN D = 15, GRAND UNIFICATION AND GENERALIZED GRAVITY IN CLIFFORD SPACES

2007 ◽  
Vol 04 (08) ◽  
pp. 1239-1257 ◽  
Author(s):  
CARLOS CASTRO
Keyword(s):  
Gauge Theory ◽  
Grand Unification ◽  
De Sitter ◽  
Sitter Group ◽  
Yang Mills ◽  
Theory Of Gravity ◽  
M Theory ◽  
Chern Simons ◽  
Topological Part ◽  
Gauge Theory Of Gravity

A novel Chern–Simons E8 gauge theory of gravity in D = 15 based on an octicE8 invariant expression in D = 16 (recently constructed by Cederwall and Palmkvist) is developed. A grand unification model of gravity with the other forces is very plausible within the framework of a supersymmetric extension (to incorporate spacetime fermions) of this Chern–Simons E8 gauge theory. We review the construction showing why the ordinary 11D Chern–Simons gravity theory (based on the Anti de Sitter group) can be embedded into a Clifford-algebra valued gauge theory and that an E8 Yang–Mills field theory is a small sector of a Clifford (16) algebra gauge theory. An E8 gauge bundle formulation was instrumental in understanding the topological part of the 11-dim M-theory partition function. The nature of this 11-dim E8 gauge theory remains unknown. We hope that the Chern–Simons E8 gauge theory of gravity in D = 15 advanced in this work may shed some light into solving this problem after a dimensional reduction.

scholarly journals A possible new cosmological redshift effect due to Λ on traveling gravitational waves in Friedmann universes

2017 ◽  
Vol 26 (14) ◽  
pp. 1750168
Author(s):  
Stefano Viaggiu
Keyword(s):  
Laplace Transform ◽  
Gravitational Waves ◽  
Einstein Condensation ◽  
De Sitter ◽  
Expansion Factor ◽  
Cosmological Redshift ◽  
Bose Einstein Condensation ◽  
Abscissa Of Convergence ◽  
Physical Consequences ◽  
Bose Einstein

In this paper, we continue the investigation concerning the propagation of gravitational waves in a cosmological background using Laplace transform. a We analyze the possible physical consequences of the result present in Ref. 19 where it is argued that a nonvanishing positive abscissa of convergence caused by the de Sitter expansion factor [Formula: see text] implies a shift in the frequencies domain of a traveling gravitational wave as measured by a comoving observer. In particular, we show that in a generic asymptotically de Sitter cosmological universe, this redshift effect does also arise. Conversely, in a universe expanding with, for example, a power law expansion, this phenomenon does not happen. This physically possible new redshift effect, although negligible for the actual very low value of [Formula: see text], can have interesting physical consequences concerning for example its relation with Bose–Einstein condensation or more speculatively with the nature of the cosmological constant in terms of gravitons, as recently suggested in Ref. 21 near a Bose–Einstein condensation phase.

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