Cosmological solutions in theD=5 Einstein-Maxwell theory coupled to matter

1991 ◽  
Vol 23 (12) ◽  
pp. 1307-1315
Author(s):  
R. Balbinot ◽  
J. C. Fabris
Keyword(s):  
Maxwell Theory ◽  
Cosmological Solutions

scholarly journals Minimal surfaces and generalized Einstein–Maxwell-dilaton theory

2019 ◽  
Vol 34 (12) ◽  
pp. 1950061
Author(s):  
M. Butler ◽  
A. M. Ghezelbash
Keyword(s):  
Cosmological Constant ◽  
Physical Properties ◽  
Minimal Surfaces ◽  
Higher Dimensions ◽  
Coupling Constants ◽  
Dilaton Field ◽  
Coupling Constant ◽  
Maxwell Theory ◽  
Five Dimensions ◽  
Cosmological Solutions

We present novel classes of nonstationary solutions to the five-dimensional generalized Einstein–Maxwell-dilaton theory with cosmological constant, in which the Maxwell’s field and the cosmological constant couple to the dilaton field. In the first class of solutions, the two nonzero coupling constants are different, while in the second class of solutions, the two coupling constants are equal to each other. We find consistent cosmological solutions with positive, negative or zero cosmological constant, where the cosmological constant depends on the value of one coupling constant in the theory. Moreover, we discuss the physical properties of the five-dimensional solutions and the uniqueness of the solutions in five dimensions by showing the solutions with different coupling constants cannot be uplifted to any Einstein–Maxwell theory in higher dimensions.

scholarly journals On the Validity of the Cosmic No-hair Conjecture in some Conformal-violating Maxwell Models

2019 ◽  
Vol 35 (2) ◽  
Author(s):  
Do Quoc Tuan
Keyword(s):  
Bianchi Type ◽  
Space Time ◽  
Kinetic Term ◽  
Type I ◽  
Anisotropic Space ◽  
Maxwell Theory ◽  
Bianchi Type I ◽  
Cosmic Inflation ◽  
Cosmological Solutions ◽  
Maxwell Models

Abstract: We will present main results of our recent investigations on the validity of the cosmic no-hair conjecture proposed by Hawking and his colleagues in some conformal-violating Maxwell models, in which a scalar field or its kinetic term is non-trivially coupled to the electromagnetic field. In particular, we will show that the studied models really admit the Bianchi type I metrics, which are homogeneous but anisotropic space time, as their stable cosmological solutions. Hence, these models turn out to be counterexamples to the cosmic no-hair conjecture. Keywords: Cosmic no-hair conjecture, cosmic inflation, Bianchi type I space time, Maxwell theory.

SIX-DIMENSIONAL BRANEWORLD COSMOLOGY

2011 ◽  
Vol 01 ◽  
pp. 189-194 ◽  
Author(s):  
MASATO MINAMITSUJI
Keyword(s):  
Magnetic Flux ◽  
Power Law ◽  
Dimensional Reduction ◽  
Extra Dimensions ◽  
Inflationary Universe ◽  
Maxwell Theory ◽  
Braneworld Cosmology ◽  
Codimension Two ◽  
Higher Dimensional ◽  
Cosmological Solutions

We derive the brane cosmological solutions in the six-dimensional Einstein-Maxwell-dilaton theory, via dimensional reduction from the higher-dimensional Einstein-Maxwell theory. Two extra dimensions are compactified by a magnetic flux and two codimension-two branes are located at the boundaries. All the cosmological solutions approach an attractor in the later times. The attractor represents a simple power-law inflationary Universe whose power is simply given by the dilatonic coupling in the theory. Then, we discuss the properties of our solutions and deduce the cosmological implications.

scholarly journals Cosmological solutions, a new wick-rotation, and the first law of thermodynamics

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
J. Gutowski ◽  
T. Mohaupt ◽  
G. Pope
Keyword(s):  
Black Holes ◽  
Internal Energy ◽  
Thermodynamic Potential ◽  
Euclidean Geometry ◽  
De Sitter ◽  
Wick Rotation ◽  
Maxwell Theory ◽  
First Law Of Thermodynamics ◽  
Cosmological Solutions ◽  
Euclidean Action

Abstract We present a modified implementation of the Euclidean action formalism suitable for studying the thermodynamics of a class of cosmological solutions containing Killing horizons. To obtain a real metric of definite signature, we perform a “triple Wick-rotation” by analytically continuing all spacelike directions. The resulting Euclidean geometry is used to calculate the Euclidean on-shell action, which defines a thermodynamic potential. We show that for the vacuum de Sitter solution, planar solutions of Einstein-Maxwell theory and a previously found class of cosmological solutions of $$ \mathcal{N} $$ N = 2 supergravity, this thermodynamic potential can be used to define an internal energy which obeys the first law of thermodynamics. Our approach is complementary to, but consistent with the isolated horizon formalism. For planar Einstein-Maxwell solutions, we find dual solutions in Einstein-anti-Maxwell theory where the sign of the Maxwell term is reversed. These solutions are planar black holes, rather than cosmological solutions, but give rise, upon a standard Wick-rotation to the same Euclidean action and thermodynamic relations.

Cosmological Solutions of Bi-metric Theories of Gravitation

1984 ◽  
Vol 496 (3) ◽  
pp. 172-178 ◽  
Author(s):  
Dierck-Ekkehard Liebscher ◽  
Jan Mücket
Keyword(s):  
Cosmological Solutions ◽  
Theories Of Gravitation

scholarly journals Cosmological solutions and growth index of matter perturbations in f(Q) gravity

2021 ◽  
Vol 103 (10) ◽  
Author(s):  
Wompherdeiki Khyllep ◽  
Andronikos Paliathanasis ◽  
Jibitesh Dutta
Keyword(s):  
Growth Index ◽  
Cosmological Solutions

scholarly journals Monodromy defects in free field theories

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Lorenzo Bianchi ◽  
Adam Chalabi ◽  
Vladimír Procházka ◽  
Brandon Robinson ◽  
Jacopo Sisti
Keyword(s):  
Entanglement Entropy ◽  
Free Field ◽  
Operator Product ◽  
Dirac Fermions ◽  
Maxwell Theory ◽  
Conformal Field ◽  
Defect Operator ◽  
Crucial Information ◽  
The One ◽  
Group Flow

Abstract We study co-dimension two monodromy defects in theories of conformally coupled scalars and free Dirac fermions in arbitrary d dimensions. We characterise this family of conformal defects by computing the one-point functions of the stress-tensor and conserved current for Abelian flavour symmetries as well as two-point functions of the displacement operator. In the case of d = 4, the normalisation of these correlation functions are related to defect Weyl anomaly coefficients, and thus provide crucial information about the defect conformal field theory. We provide explicit checks on the values of the defect central charges by calculating the universal part of the defect contribution to entanglement entropy, and further, we use our results to extract the universal part of the vacuum Rényi entropy. Moreover, we leverage the non-supersymmetric free field results to compute a novel defect Weyl anomaly coefficient in a d = 4 theory of free $$ \mathcal{N} $$ N = 2 hypermultiplets. Including singular modes in the defect operator product expansion of fundamental fields, we identify notable relevant deformations in the singular defect theories and show that they trigger a renormalisation group flow towards an IR fixed point with the most regular defect OPE. We also study Gukov-Witten defects in free d = 4 Maxwell theory and show that their central charges vanish.

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