Scalar Fields on Anti-de Sitter Background

2014 ◽  
pp. 53-60
Author(s):  
Gyula Fodor ◽  
Péter Forgács ◽  
Philippe Grandclément
Keyword(s):  
Scalar Fields ◽  
De Sitter ◽  
Sitter Background

scholarly journals Missing scalars at the cosmological collider

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Qianshu Lu ◽  
Matthew Reece ◽  
Zhong-Zhi Xianyu
Keyword(s):  
Scalar Fields ◽  
Thermal Mass ◽  
De Sitter ◽  
Typically Develop ◽  
Useful Signal ◽  
Light Scalar ◽  
Density Perturbations ◽  
Sitter Background ◽  
Spatially Varying

Abstract Light scalar fields typically develop spatially varying backgrounds during inflation. Very often they do not directly affect the density perturbations, but interact with other fields that do leave nontrivial signals in primordial perturbations. In this sense they become “missing scalars” at the cosmological collider. We study potentially observable signals of these missing scalars, focusing on a special example where a missing scalar distorts the usual oscillatory features in the squeezed bispectrum. The distortion is also a useful signal distinguishing the de Sitter background induced thermal mass from a constant intrinsic mass.

scholarly journals CASIMIR EFFECT FOR A SPHERICAL SHELL IN DE SITTER SPACE–TIME WITH SIGNATURE CHANGE

2008 ◽  
Vol 17 (12) ◽  
pp. 2261-2268
Author(s):  
M. R. SETARE ◽  
F. DARABI
Keyword(s):  
Spherical Shell ◽  
Casimir Effect ◽  
Scalar Fields ◽  
Dirichlet Boundary Conditions ◽  
Massless Scalar ◽  
Late Time ◽  
De Sitter ◽  
Signature Change ◽  
Sitter Background ◽  
Cosmological Constants

We calculate the Casimir stress on a spherical shell in a de Sitter background corresponding to different metric signatures and cosmological constants, for massless scalar fields that satisfy Dirichlet boundary conditions on the shell. We show that a contribution appears due to signature change, which leads to late-time expansion of the bubbles in this background.

ENTROPY OF SCALAR FIELDS IN REISSNER–NORDSTRÖM–(ANTI-)DE SITTER SPACETIMES

1996 ◽  
Vol 11 (25) ◽  
pp. 2027-2036 ◽  
Author(s):  
RONG-GEN CAI ◽  
YUAN-ZHONG ZHANG
Keyword(s):  
Black Holes ◽  
Naked Singularity ◽  
Scalar Fields ◽  
De Sitter Space ◽  
Brick Wall ◽  
De Sitter Spacetime ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Sitter Spacetime ◽  
Sitter Background

The entropy of a free scalar field is calculated in the Reissner–Nordström–(anti-)de Sitter spacetimes. Due to the presence of the cosmological horizon in the Reissner–Nordström–de Sitter spacetime, we introduce a cutoff at the cosmological horizon, besides the cutoff at the horizon of black holes in the brick wall model. The entropy is found to be the sum of two terms, which are proportional to the area of the cosmological horizon and of black hole horizon, respectively. In the Reissner–Nordström–anti-de Sitter spacetime the contribution of the anti-de Sitter background to the entropy of scalar fields vanishes when an infinite volume is taken. The entropy of scalar fields is also evaluated in some special backgrounds described by solutions of Einstein–Maxwell equations with a cosmological constant, such as the cold black holes, lukewarm black holes, ultracold solutions, a naked singularity in de Sitter space, and the de Sitter space. The physical meaning of some results is briefly discussed.

scholarly journals CASIMIR STRESS ON PARALLEL PLATES IN DE SITTER SPACE WITH SIGNATURE CHANGE

2007 ◽  
Vol 22 (08n09) ◽  
pp. 1771-1779 ◽  
Author(s):  
M. R. SETARE
Keyword(s):  
Scalar Fields ◽  
Massless Scalar ◽  
Parallel Plates ◽  
False Vacuum ◽  
De Sitter ◽  
Signature Change ◽  
True Vacuum ◽  
Sitter Background ◽  
Robin Boundary ◽  
Cosmological Constants

The Casimir stress on two parallel plates in a de Sitter background corresponding to different metric signatures and cosmological constants is calculated for massless scalar fields satisfying Robin boundary conditions on the plates. Our calculation shows that for the parallel plates with false vacuum between and true vacuum outside, the total Casimir pressure leads to an attraction of the plates at very early universe.

scholarly journals Hawking’s radiation in non-stationary rotating de Sitter background

2011 ◽  
Vol 333 (1) ◽  
pp. 175-185 ◽  
Author(s):  
N. Ibohal ◽  
T. Ibungochouba
Keyword(s):  
De Sitter ◽  
Sitter Background

Dirac particle in electric field with confining scalar potential on (anti)-de Sitter background

2018 ◽  
Vol 33 (34) ◽  
pp. 1850202 ◽  
Author(s):  
N. Messai ◽  
B. Hamil ◽  
A. Hafdallah
Keyword(s):  
Energy Spectrum ◽  
Dirac Equation ◽  
Electric Field ◽  
Scalar Potential ◽  
Dirac Particle ◽  
Wave Functions ◽  
De Sitter ◽  
Sitter Background ◽  
Position Representation

In this paper, we study the (1 + 1)-dimensional Dirac equation in the presence of electric field and scalar linear potentials on (anti)-de Sitter background. Using the position representation, the energy spectrum and the corresponding wave functions are exactly obtained.

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 The Ambiguity in the Definition and Behavior of the Gravitational and Cosmological `Coupling Constants’ in the Theory of Induced Gravity

Symmetry ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 81 ◽  
Author(s):  
Farkhat Zaripov
Keyword(s):  
Gravitational Interaction ◽  
Scalar Fields ◽  
Coupling Constants ◽  
De Sitter ◽  
Induced Gravity ◽  
Mean Values ◽  
Gravitational And Cosmological Constants ◽  
Centrally Symmetric ◽  
Walker Metric ◽  
Cosmological Constants

This work is the extension of author`s research, where the modified theory of induced gravity (MTIG) is proposed. The theory describes two systems (stages): Einstein (ES) and “restructuring” (RS). We consider equations with quadratic potential that are symmetric with respect to scale transformations. The solutions of the equations obtained for the case of spaces defined by the Friedman-Robertson-Walker metric, as well as for a centrally symmetric space are investigated. In our model arise effective gravitational and cosmological “constants”, which are defined by the “mean square” of the scalar fields. In obtained solutions the values of such parameters as “Hubble parameter”, gravitational and cosmological “constants” in the RS stage fluctuate near monotonically evolving mean values. These parameters are matched with observational data, described as phenomena of dark energy and dark matter. The MTIG equations for the case of a centrally symmetric gravitational field, in addition to the Schwarzschild-de Sitter solutions, contain solutions that lead to the new physical effects at large distances from the center. The Schwarzschild-Sitter solution becomes unstable and enters the oscillatory regime. For distances greater than a certain critical value, the following effects can appear: deviation from General relativity and Newton’s law of gravitational interaction, antigravity.

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