scholarly journals Manifold invariants affect dynamics in anti de Sitter gravity

2013 ◽  
Vol 91 (6) ◽  
pp. 465-466 ◽  
Author(s):  
Tomáš Liko
Keyword(s):  
Cosmological Constant ◽  
Configuration Space ◽  
De Sitter ◽  
First Order ◽  
Diffeomorphism Invariance ◽  
Negative Cosmological Constant ◽  
Weight Factors ◽  
Fixed Weight ◽  
Affect Dynamics

The first-order Holst action with negative cosmological constant is rendered finite by requiring functional differentiability on the configuration space of tetrads and connections. The surface terms that arise in the action for anti de Sitter gravity are equivalent to the Euler and Pontryagin densities with fixed weight factors; these terms modify the Noether charges that arise from diffeomorphism invariance of the action.

scholarly journals Thin-Shell Wormholes in Einstein and Einstein–Gauss–Bonnet Theories of Gravity

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 197
Author(s):  
Takafumi Kokubu ◽  
Tomohiro Harada
Keyword(s):  
Cosmological Constant ◽  
Electric Charge ◽  
Thin Shell ◽  
De Sitter ◽  
Negative Cosmological Constant ◽  
Special Cases ◽  
Theories Of Gravity ◽  
Thin Shell Wormholes ◽  
Theory Of Gravitation ◽  
The Stability

We review recent works on the possibility for eternal existence of thin-shell wormholes on Einstein and Einstein–Gauss–Bonnet gravity. We introduce thin-shell wormholes that are categorized into a class of traversable wormhole solutions. After that, we discuss stable thin-shell wormholes with negative-tension branes in Reissner–Nordström–(anti) de Sitter spacetimes in d-dimensional Einstein gravity. Imposing Z2 symmetry, we construct and classify traversable static thin-shell wormholes in spherical, planar and hyperbolic symmetries. It is found that the spherical wormholes are stable against spherically symmetric perturbations. It is also found that some classes of wormholes in planar and hyperbolic symmetries with a negative cosmological constant are stable against perturbations preserving symmetries. In most cases, stable wormholes are found with the appropriate combination of an electric charge and a negative cosmological constant. However, as special cases, there are stable wormholes even with a vanishing cosmological constant in spherical symmetry and with a vanishing electric charge in hyperbolic symmetry. Subsequently, the existence and dynamical stability of traversable thin-shell wormholes with electrically neutral negative-tension branes is discussed in Einstein–Gauss–Bonnet theory of gravitation. We consider radial perturbations against the shell for the solutions, which have the Z2 symmetry. The effect of the Gauss–Bonnet term on the stability depends on the spacetime symmetry.

scholarly journals GAUGED ADS–MAXWELL ALGEBRA AND GRAVITY

2011 ◽  
Vol 26 (36) ◽  
pp. 2689-2696 ◽  
Author(s):  
R. DURKA ◽  
J. KOWALSKI-GLIKMAN ◽  
M. SZCZACHOR
Keyword(s):  
Cosmological Constant ◽  
Dynamical Model ◽  
Gauge Fields ◽  
De Sitter ◽  
Field Equations ◽  
Negative Cosmological Constant ◽  
Bf Theory ◽  
Maxwell Fields ◽  
Dynamical Field

We deform the anti-de Sitter algebra by adding additional generators [Formula: see text], forming in this way the negative cosmological constant counterpart of the Maxwell algebra. We gauge this algebra and construct a dynamical model with the help of a constrained BF theory. It turns out that the resulting theory is described by the Einstein–Cartan action with Holst term, and the gauge fields associated with the Maxwell generators [Formula: see text] appear only in topological terms that do not influence dynamical field equations. We briefly comment on the extension of this construction, which would lead to a nontrivial Maxwell fields dynamics.

scholarly journals EXACT NONSPHERICAL RELATIVISTIC STAR

2010 ◽  
Vol 25 (12) ◽  
pp. 2573-2583
Author(s):  
SUSHANT G. GHOSH ◽  
D. W. DESHKAR
Keyword(s):  
Cosmological Constant ◽  
Analytical Solutions ◽  
De Sitter Space ◽  
De Sitter ◽  
Einstein’S Field Equations ◽  
Field Equations ◽  
Relativistic Star ◽  
Plane Symmetric ◽  
Negative Cosmological Constant ◽  
Einstein's Equation

Einstein's equation with a negative cosmological constant admit solutions which are asymptotically anti-de Sitter. We obtain Vaidya-like solutions to include both a null fluid and a string fluid in nonspherical (plane symmetric and cylindrical symmetric) anti-de Sitter space–times. Assuming that string fluid diffuse, we find analytical solutions to Einstein's field equations. Thus we extend the approach proposed by Glass and Krisch to nonspherical space–times with a negative cosmological constant. Some other exacts solutions are also presented and discussed.

scholarly journals On supersymmetric AdS4 orientifold vacua

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Fernando Marchesano ◽  
Eran Palti ◽  
Joan Quirant ◽  
Alessandro Tomasiello
Keyword(s):  
String Theory ◽  
Cosmological Constant ◽  
Bianchi Identities ◽  
Expansion Parameter ◽  
First Order ◽  
Ricci Flat ◽  
Key Features ◽  
One To One ◽  
Calabi Yau Manifolds

Abstract In this work we study ten-dimensional solutions to type IIA string theory of the form AdS4 × X6 which contain orientifold planes and preserve $$ \mathcal{N} $$ N = 1 supersymmetry. In particular, we consider solutions which exhibit some key features of the four-dimensional DGKT proposal for compactifications on Calabi-Yau manifolds with fluxes, and in this sense may be considered their ten-dimensional uplifts. We focus on the supersymmetry equations and Bianchi identities, and find solutions to these that are valid at the two-derivative level and at first order in an expansion parameter which is related to the AdS cosmological constant. This family of solutions is such that the background metric is deformed from the Ricci-flat one to one exhibiting SU(3) × SU(3)-structure, and dilaton gradients and warp factors are induced.

scholarly journals de Sitter in non-supersymmetric string theories: no-go theorems and brane-worlds

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Ivano Basile ◽  
Stefano Lanza
Keyword(s):  
Flux Compactifications ◽  
Cosmological Constant ◽  
Dimensional Reduction ◽  
Brane World ◽  
De Sitter ◽  
Top Down ◽  
Brane Worlds ◽  
Concrete Realization ◽  
String Models ◽  
String Theories

Abstract We study de Sitter configurations in ten-dimensional string models where supersymmetry is either absent or broken at the string scale. To this end, we derive expressions for the cosmological constant in general warped flux compactifications with localized sources, which yield no-go theorems that extend previous works on supersymmetric cases. We frame our results within a dimensional reduction and connect them to a number of Swampland conjectures, corroborating them further in the absence of supersymmetry. Furthermore, we construct a top-down string embedding of de Sitter brane-world cosmologies within unstable anti-de Sitter landscapes, providing a concrete realization of a recently revisited proposal.

scholarly journals Non-Abelian gravitating solitons with negative cosmological constant

2004 ◽  
Vol 21 (6) ◽  
pp. 1667-1683 ◽  
Author(s):  
Peter Breitenlohner ◽  
Dieter Maison ◽  
George Lavrelashvili
Keyword(s):  
Cosmological Constant ◽  
Negative Cosmological Constant

scholarly journals Relationship between Bondi–Sachs quantities and source of gravitational radiation in asymptotically de Sitter spacetime

2018 ◽  
Vol 27 (04) ◽  
pp. 1850046 ◽  
Author(s):  
Xiaokai He ◽  
Jiliang Jing ◽  
Zhoujian Cao
Keyword(s):  
Cosmological Constant ◽  
Gravitational Wave ◽  
Gravitational Radiation ◽  
The Other ◽  
Perturbation Approach ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Positive Cosmological Constant ◽  
Sitter Spacetime ◽  
Explicit Expressions

Gravitational radiation plays an important role in astrophysics. Based on the fact that our universe is expanding, the gravitational radiation when a positive cosmological constant is presented has been studied along with two different ways recently, one is the Bondi–Sachs (BS) framework in which the result is shown by BS quantities in the asymptotic null structure, the other is the perturbation approach in which the result is presented by the quadrupoles of source. Therefore, it is worth to interpret the quantities in asymptotic null structure in terms of the information of the source. In this paper, we investigate this problem and find the explicit expressions of BS quantities in terms of the quadrupoles of source in asymptotically de Sitter spacetime. We also estimate how far away the source is, the cosmological constant may affect the detection of the gravitational wave.

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