scholarly journals SPONTANEOUS DECAY OF THE EFFECTIVE COSMOLOGICAL CONSTANT

1998 ◽  
Vol 13 (07) ◽  
pp. 571-580 ◽  
Author(s):  
MURAT ÖZER ◽  
M. O. TAHA
Keyword(s):  
Cosmological Constant ◽  
De Sitter Space ◽  
Space Time ◽  
Time Dependent ◽  
Spontaneous Decay ◽  
Quantum Fields ◽  
De Sitter ◽  
Initial Value ◽  
Effective Time ◽  
Effective Cosmological Constant

We discuss the notion that quantum fields may induce an effective time-dependent cosmological constant which decays from a large initial value. It is shown that such cosmological models are viable in a non-de Sitter space–time.

THERMODYNAMICS OF de SITTER SPACE–TIME IN YORK'S FORMALISM

2001 ◽  
Vol 16 (23) ◽  
pp. 1487-1492 ◽  
Author(s):  
BO-BO WANG ◽  
CHAO-GUANG HUANG
Keyword(s):  
Black Holes ◽  
Cosmological Constant ◽  
Path Integral ◽  
De Sitter Space ◽  
Space Time ◽  
Integral Approach ◽  
De Sitter ◽  
First Law Of Thermodynamics ◽  
Path Integral Approach ◽  
Thermodynamics Of Black Holes

The York's formalism of path-integral approach to the thermodynamics of black holes is applied to de Sitter space–time. The first law of thermodynamics for de Sitter space–time is given, which includes a "work term" with respect to the cosmological constant.

Verifying the universe is another way to ds space-time

2021 ◽  
Author(s):  
Wen-Xiang Chen
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Cosmological Constant ◽  
Uncertainty Principle ◽  
De Sitter Space ◽  
Space Time ◽  
De Sitter ◽  
The Given ◽  
The Universe

In this paper, it is explained that the role of the cosmological constant in the De Sitter space is similar to that of the preset boundary conditions in the superradiation phenomenon. In the previous literature, superradiance at a given boundary condition can cause the uncertainty principle to be less extreme, and so the uncertainty principle to be less extreme without the given boundary condition, might be one way to prove that the universe is ds spacetime.

scholarly journals Instanton interaction in de Sitter space–time

2018 ◽  
Vol 33 (33) ◽  
pp. 1850200
Author(s):  
Dimitrios Metaxas
Keyword(s):  
Cosmological Constant ◽  
Decay Rate ◽  
De Sitter Space ◽  
Space Time ◽  
Tunneling Rate ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Vacuum Decay ◽  
Background Space

Because of the presence of a cosmological horizon, the dilute instanton gas approximation used for the derivation of the Coleman–De Luccia tunneling rate in de Sitter space–time receives additional contributions due to the finite instanton separation. Here, I calculate the first corrections to the vacuum decay rate that arise from this effect and depend on the parameters of the theory and the cosmological constant of the background space–time.

scholarly journals Exact solutions to Einstein–Maxwell theory on Eguchi–Hanson space

2017 ◽  
Vol 32 (17) ◽  
pp. 1750098 ◽  
Author(s):  
A. M. Ghezelbash ◽  
V. Kumar
Keyword(s):  
Cosmological Constant ◽  
Exact Solutions ◽  
De Sitter Space ◽  
Space Time ◽  
De Sitter ◽  
Maxwell Theory ◽  
Analytical Functions ◽  
Higher Dimensional ◽  
All Solutions ◽  
Metric Functions

In this paper, we construct explicit analytical exact solutions to the six and higher-dimensional Einstein–Maxwell theory. In all solutions, a subspace of the metric is the Eguchi–Hanson space where the metric functions are completely determined in terms of known analytical functions. Moreover, we find the solutions can be extended from nonstationary exact solutions to Einstein–Maxwell theory with cosmological constant. We show that the solutions are asymptotically expanding patches of de Sitter space–time.

scholarly journals GRAVITATIONAL TRAPPING FOR EXTENDED EXTRA DIMENSION

2002 ◽  
Vol 11 (10) ◽  
pp. 1639-1642 ◽  
Author(s):  
MERAB GOGBERASHVILI
Keyword(s):  
Cosmological Constant ◽  
Extra Dimension ◽  
De Sitter Space ◽  
Space Time ◽  
De Sitter ◽  
Einstein’S Equations ◽  
Einstein's Equations ◽  
Newton's Law ◽  
Newton’S Law

The solution of Einstein's equations for 4-brane embedded in five-dimensional Anti-de Sitter space–time is found. It is shown that the cosmological constant can provide the existence of ordinary four-dimensional Newton's law and trapping of a matter on the brane.

scholarly journals New reflections on higher dimensional linearized gravity

2019 ◽  
Vol 65 (5 Sept-Oct) ◽  
pp. 536
Author(s):  
C. García-Quintero ◽  
A. Ortiz ◽  
And J. A. Nieto
Keyword(s):  
Quantum Gravity ◽  
Cosmological Constant ◽  
De Sitter Space ◽  
Space Time ◽  
Graviton Mass ◽  
De Sitter ◽  
Linearized Gravity ◽  
Background Space ◽  
Higher Dimensional

We make a number of remarks on linearized gravity with cosmological constant in any dimension, which we argue, can be useful in a quantum gravity framework. For this purpose we assume that the background space-time metric corresponds to the de Sitter or anti-de Sitter space. Moreover, we make some interesting observations, putting special attention on the possible scenario of  a graviton-tachyon connection, via the graviton mass and the cosmological constant correspondence. We compare our proposed formalism with the Novello and Neves approach.

scholarly journals On Gravitational Entropy of de Sitter Universe

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
S. C. Ulhoa ◽  
E. P. Spaniol
Keyword(s):  
Phase Transition ◽  
Cosmological Constant ◽  
De Sitter Space ◽  
Teleparallel Gravity ◽  
Space Time ◽  
Gravitational Energy ◽  
De Sitter ◽  
First Law Of Thermodynamics ◽  
Gravitational Entropy ◽  
De Sitter Universe

The paper deals with the calculation of the gravitational entropy in the context of teleparallel gravity for de Sitter space-time. In such a theory it is possible to define gravitational energy and pressure; thus we use those expressions to construct the gravitational entropy. We use the temperature as a function of the cosmological constant and write the first law of thermodynamics from which we obtain the entropy. In the limit Λ≪1 we find that the entropy is proportional to volume, for a specific temperature’s choice; we find that ΔS≥0 as well. We also identify a phase transition in de Sitter space-time by analyzing the specific heat.

scholarly journals QUANTUM BOUNDS FOR GRAVITATIONAL DE SITTER ENTROPY AND THE CARDY–VERLINDE FORMULA

2001 ◽  
Vol 16 (18) ◽  
pp. 1181-1192 ◽  
Author(s):  
S. NOJIRI ◽  
O. OBREGON ◽  
S. D. ODINTSOV ◽  
H. QUEVEDO ◽  
M. P. RYAN
Keyword(s):  
Cosmological Constant ◽  
De Sitter Space ◽  
Quantum Corrections ◽  
Hamiltonian Constraint ◽  
De Sitter ◽  
Entropy Formula ◽  
Verlinde Formula ◽  
Effective Cosmological Constant ◽  
Different Types ◽  
Friedmann Robertson Walker

We analyze different types of quantum corrections to the Cardy–Verlinde entropy formula in a Friedmann–Robertson–Walker universe and in an (anti)-de Sitter space. In all cases we show that quantum corrections can be represented by an effective cosmological constant which is then used to redefine the parameters entering the Cardy–Verlinde formula so that it becomes valid also with quantum corrections, a fact that we interpret as a further indication of its universality. A proposed relation between Cardy–Verlinde formula and the ADM Hamiltonian constraint is given.

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