scholarly journals Properties of Scalar Perturbations Generated by Conformal Scalar Field

2011 ◽  
Vol 190 ◽  
pp. 120-134 ◽  
Author(s):  
Maxim Libanov ◽  
Sergey Mironov ◽  
Valery Rubakov
Keyword(s):  
Scalar Field ◽  
Conformal Scalar Field ◽  
Scalar Perturbations

scholarly journals A cosmic microscope for the preheating era

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
JiJi Fan ◽  
Zhong-Zhi Xianyu
Keyword(s):  
Scalar Field ◽  
Nonlinear Effect ◽  
Large Scale ◽  
Nonlinear Effects ◽  
Light Fields ◽  
Unique Probe ◽  
Light Scalar ◽  
Spatially Varying ◽  
Near Future ◽  
Scalar Perturbations

Abstract Light fields with spatially varying backgrounds can modulate cosmic preheating, and imprint the nonlinear effects of preheating dynamics at tiny scales on large scale fluctuations. This provides us a unique probe into the preheating era which we dub the “cosmic microscope”. We identify a distinctive effect of preheating on scalar perturbations that turns the Gaussian primordial fluctuations of a light scalar field into square waves, like a diode. The effect manifests itself as local non-Gaussianity. We present a model, “modulated partial preheating”, where this nonlinear effect is consistent with current observations and can be reached by near future cosmic probes.

Higgs-like field from extended theory of gravitation

2014 ◽  
Vol 11 (02) ◽  
pp. 1460001
Author(s):  
L. Fatibene ◽  
M. Ferraris ◽  
G. Magnano ◽  
M. Palese ◽  
M. Capone ◽  
...  
Keyword(s):  
Scalar Field ◽  
Extended Theory ◽  
Theory Of Gravitation ◽  
Conformal Scalar Field

We shall consider possible potentials emerging in (purely metric) f(R)-theories for the conformal scalar field. We shall discuss possible approaches to determine models with specific potentials and show that some potentials qualitatively similar to the typical Higgs potentials are allowed.

WORMHOLE SOLUTIONS IN R1×S1×S2 TOPOLOGICAL SPACE

1992 ◽  
Vol 07 (27) ◽  
pp. 2463-2467 ◽  
Author(s):  
SUBENOY CHAKRABORTY
Keyword(s):  
Scalar Field ◽  
Topological Space ◽  
Cosmological Constant ◽  
Symmetric Tensor ◽  
Einstein Equations ◽  
Second Step ◽  
Anisotropic Space ◽  
First Case ◽  
Frw Metric ◽  
Conformal Scalar Field

Wormhole solutions are discussed for two different physical situations in the background of a homogeneous anisotropic space-time. In the first case, the wormholes are solutions of the Euclidean Einstein equations with a cosmological constant and a two-index anti-symmetric tensor for monopole configuration on a space with three-surface of topology S1×S2. In the second step, conformal scalar field is coupled to gravity and wormhole are considered for both λ=0 and λ>0. These results are analogous to the wormhole solutions for FRW metric.

scholarly journals Quasinormal Modes of Charged Black Holes in Higher-Dimensional Einstein-Power-Maxwell Theory

Axioms ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 33 ◽  
Author(s):  
Grigoris Panotopoulos
Keyword(s):  
Black Holes ◽  
Scalar Field ◽  
Electric Charge ◽  
Quasinormal Modes ◽  
Space Time ◽  
Maxwell Theory ◽  
Charged Black Holes ◽  
Higher Dimensional ◽  
The Impact ◽  
Scalar Perturbations

We compute the quasinormal frequencies for scalar perturbations of charged black holes in five-dimensional Einstein-power-Maxwell theory. The impact on the spectrum of the electric charge of the black holes, of the angular degree, of the overtone number, and of the mass of the test scalar field is investigated in detail. The quasinormal spectra in the eikonal limit are computed as well for several different space-time dimensionalities.

STABILITY OF SCHWARZSCHILD BLACK HOLE IN THE MASSIVE BRANS-DICKE THEORY

1986 ◽  
Vol 01 (03) ◽  
pp. 709-729 ◽  
Author(s):  
O.J. KWON ◽  
Y.D. KIM ◽  
Y.S. MYUNG ◽  
B.H. CHO ◽  
Y.J. PARK
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Gravitational Wave ◽  
Scalar Wave ◽  
Schwarzschild Black Hole ◽  
The Real ◽  
Gravitational Perturbations ◽  
Scalar Perturbations

For the nontachyonic mass (c<0, µ2<6), we have found that all nonstatic perturbations (odd-, even-parity and scalar perturbations) allow only the real values of frequency k. This means that the black hole in the massive Brans-Dicke theory is classically stable. However, for the tachyonic mass of scalar field (c>0, µ2>6), we find that the massive Brans-Dicke theory is classically unstable. We also emphasize that the potential forms of odd-parity perturbations is simply given by the pure-gravitational perturbations. For the even-parity case, we obtain the same potential just as Zerilli’s case by combining the even-parity gravitational wave and scalar wave. For static perturbations (k=0) and c>0, only the odd- and even-parity cases with L=0, 1 is allowed to avoid exponentially growing modes.

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