Fluctuations produced by the cosmological constant in the empty Bianchi type-IX model

1982 ◽  
Vol 14 (9) ◽  
pp. 751-768 ◽  
Author(s):  
H. Sirousse-Zia
Keyword(s):  
Cosmological Constant ◽  
Bianchi Type

Cosmological constant Λ in f(R,T) modified gravity

2016 ◽  
Vol 13 (05) ◽  
pp. 1650058 ◽  
Author(s):  
Gyan Prakash Singh ◽  
Binaya Kumar Bishi ◽  
Pradyumn Kumar Sahoo
Keyword(s):  
Cosmological Model ◽  
Cosmological Constant ◽  
Modified Gravity ◽  
Bianchi Type ◽  
Field Equations ◽  
Type Iii ◽  
Expansion Scalar ◽  
Modified Theory Of Gravity ◽  
Shear Scalar ◽  
Modified Theory

In this paper, we have studied the Bianchi type-III cosmological model in the presence of cosmological constant in the context of [Formula: see text] modified theory of gravity. Here, we have discussed two classes of [Formula: see text] gravity, i.e. [Formula: see text] and [Formula: see text]. In both classes, the modified field equations are solved by the relation expansion scalar [Formula: see text] that is proportional to shear scalar [Formula: see text] which gives [Formula: see text], where [Formula: see text] and [Formula: see text] are metric potentials. Also we have discussed some physical and kinematical properties of the models.

scholarly journals Quantization of the Bianchi type-IX model in supergravity with a cosmological constant

1994 ◽  
Vol 49 (10) ◽  
pp. 5246-5251 ◽  
Author(s):  
A. D. Y. Cheng ◽  
P. D. D'Eath ◽  
P. R. L. V. Moniz
Keyword(s):  
Cosmological Constant ◽  
Bianchi Type

Cosmological constant in the Bianchi type-I-modified Brans-Dicke cosmology

Pramana ◽  
2003 ◽  
Vol 60 (1) ◽  
pp. 21-27 ◽  
Author(s):  
A. K. Azad ◽  
J. N. Islam
Keyword(s):  
Cosmological Constant ◽  
Bianchi Type ◽  
Type I ◽  
Bianchi Type I

Self-gravitating skyrmions

2016 ◽  
Vol 25 (09) ◽  
pp. 1641009
Author(s):  
Eloy Ayón-Beato ◽  
Fabrizio Canfora ◽  
Jorge Zanelli
Keyword(s):  
Cosmological Constant ◽  
Analytic Continuation ◽  
Direct Product ◽  
Regular Solution ◽  
Topological Charge ◽  
Bianchi Type ◽  
Product Formula ◽  
The Self ◽  
Energy Conditions ◽  
Stress Energy

A self-gravitating Skyrmion is an analytic and globally regular solution of the Einstein–Skyrme system with nonvanishing topological charge. The spacetime is the direct product [Formula: see text] and the Skyrmion is the self-gravitating generalization of the static hedgehog solution of Manton and Ruback. This solution can be promoted to a dynamical one in which the spacetime is a cosmology of the Bianchi type-IX and, through an analytic continuation, it can also be turned into a transversable asymptotically AdS Lorentzian wormhole. The stress–energy of this wormhole satisfies physically realistic energy conditions and the only “exotic matter” required by it is a negative cosmological constant.

scholarly journals GLOBAL REGULAR SOLUTION FOR THE EINSTEIN-MAXWELL-BOLTZMANN-SCALAR FIELD SYSTEM IN A BIANCHI TYPE-I SPACE-TIME

2017 ◽  
Vol 13 (1) ◽  
pp. 7087-7118 ◽  
Author(s):  
Noutchegueme Norbert
Keyword(s):  
Scalar Field ◽  
Global Existence ◽  
Cosmological Constant ◽  
Existence Theorem ◽  
Regular Solution ◽  
Existence And Uniqueness ◽  
Bianchi Type ◽  
Type I ◽  
Field System ◽  
Global Existence Theorem

We prove an existence and uniqueness of regular solution to the Einstein-Maxwell-Boltzmann-Scalar Field system with pseudo-tensor of pressure and the cosmological constant globaly in time. We clarify the choice of the function spaces and we establish step by step all the essential energy estimations leading to the global existence theorem.

scholarly journals GRAVITATIONAL INSTANTONS IN ASHTEKAR’S FORMALISM

1996 ◽  
Vol 11 (15) ◽  
pp. 2707-2720
Author(s):  
HIDEKI ISHIHARA ◽  
HIROTO KUBOTANI ◽  
TAKESHI FUKUYAMA
Keyword(s):  
Cosmological Constant ◽  
Bianchi Type ◽  
Canonical Formalism ◽  
Coupled System ◽  
The Self ◽  
Initial Surface ◽  
Gravitational Instantons ◽  
Hamiltonian Equations ◽  
Self Duality ◽  
Duality Condition

Gravitational instantons of Bianchi type IX space are constructed in Ashtekar’s canonical formalism. Instead of solving the self-duality condition, we fully solve the constraint on the “initial surface” and “Hamiltonian equations.” This formalism is applicable to the matter coupled system with cosmological constant.

scholarly journals Bianchi Type-I Universe with Cosmological Constant and Quadratic Equation of State inf(R,T)Modified Gravity

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
G. P. Singh ◽  
Binaya K. Bishi
Keyword(s):  
Equation Of State ◽  
Cosmological Constant ◽  
Modified Gravity ◽  
Bianchi Type ◽  
Quadratic Equation ◽  
Type I ◽  
Field Equations ◽  
Bianchi Type I ◽  
Bianchi Type I Universe ◽  
Quadratic Equation Of State

This paper deals with the study of Bianchi type-I universe in the context off(R,T)gravity. Einstein’s field equations inf(R,T)gravity have been solved in the presence of cosmological constantΛand quadratic equation of state (EoS)p=αρ2-ρ, whereα≠0is a constant. Here, we have discussed two classes off(R,T)gravity; that is,f(R,T)=R+2f(T)andf(R,T)=f1(R)+f2(T). A set of models has been taken into consideration based on the plausible relation. Also, we have studied some physical and kinematical properties of the models.

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