Renormalized evolution equations for the back-reaction problem with a self-interacting scalar field

1988 ◽  
Vol 37 (8) ◽  
pp. 2170-2181 ◽  
Author(s):  
J. P. Paz ◽  
F. D. Mazzitelli
Keyword(s):  
Scalar Field ◽  
Evolution Equations ◽  
Back Reaction ◽  
Reaction Problem

scholarly journals VACUUM QUANTUM EFFECTS OF NONCONFORMAL SCALAR FIELD IN A NONSINGULAR COSMOLOGICAL MODEL

1998 ◽  
Vol 07 (05) ◽  
pp. 779-792 ◽  
Author(s):  
M. NOVELLO ◽  
V. B. BEZERRA ◽  
V. M. MOSTEPANENKO
Keyword(s):  
Scalar Field ◽  
Energy Density ◽  
Negative Energy ◽  
Back Reaction ◽  
Energy Tensor ◽  
Stress Energy Tensor ◽  
Negative Energy Density ◽  
Stress Energy ◽  
Nonsingular Cosmological Model ◽  
Reaction Problem

The total vacuum stress-energy tensor of nonconformal scalar field is calculated in a nonsingular metric determined by some background matter with the effective negative energy density and pressure. The corrections due to the field nonconformity are shown to dominate the conformal contributions for some cases. The back reaction problem of vacuum stress-energy tensor upon the background metric is also discussed.

scholarly journals Static black holes without spatial isometries: From AdS multipoles to electrovacuum scalarization

2020 ◽  
Vol 29 (11) ◽  
pp. 2041016
Author(s):  
Carlos Herdeiro ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Scalar Field ◽  
General Framework ◽  
Bound State ◽  
Back Reaction ◽  
Zero Modes ◽  
Spherical Topology ◽  
Continuous Symmetries

We review recent results on the existence of static black holes (BHs) without spatial isometries in four spacetime dimensions and propose a general framework for their study. These configurations are regular on and outside a horizon of spherical topology. Two different mechanisms allowing for their existence are identified. The first one relies on the presence of a solitonic limit of the BHs; when the solitons have no spatial isometries, the BHs, being a nonlinear bound state between the solitons and a horizon, inherit this property. The second one is related to BH scalarization, and the existence of zero modes of the scalar field without isometries around a spherical horizon. When the zero modes have no spatial isometries, the back-reaction of their nonlinear continuation makes the scalarized BHs inherit the absence of spatial continuous symmetries. A number of general features of the solutions are discussed together with possible generalizations.

Complexity factors for static axial system in self-interacting Brans–Dicke gravity

2019 ◽  
Vol 16 (11) ◽  
pp. 1950174 ◽  
Author(s):  
M. Sharif ◽  
Amal Majid
Keyword(s):  
Scalar Field ◽  
Evolution Equations ◽  
Riemann Tensor ◽  
Additional Source ◽  
Bianchi Identities ◽  
Structure Scalars ◽  
Physical Attributes ◽  
Physical Features ◽  
Axial System

This paper explores the physical attributes of a static axial source that induce complexity within the fluid in the background of self-interacting Brans–Dicke theory. Bel’s approach is used to split the Riemann tensor and construct structure scalars that involve physical features of the fluid in the presence of scalar field. Using the evolution equations derived from Bianchi identities as well as structure scalars, five complexity factors are identified which include constraints on the scalar field. Finally, the conditions of vanishing complexity are used to present solutions for an anisotropic inhomogeneous spheroid. It is concluded that scalar field is an additional source of complexity.

The thermodynamical approach to the back reaction problem

1993 ◽  
Vol 25 (12) ◽  
pp. 1267-1275 ◽  
Author(s):  
Chao Guang Huang ◽  
Liao Liu ◽  
Zheng Zhao
Keyword(s):  
Back Reaction ◽  
Reaction Problem

Exact solutions for scalar field cosmology in f(R) gravity

2017 ◽  
Vol 32 (30) ◽  
pp. 1750164 ◽  
Author(s):  
S. D. Maharaj ◽  
R. Goswami ◽  
S. V. Chervon ◽  
A. V. Nikolaev
Keyword(s):  
Scalar Field ◽  
Exact Solutions ◽  
Scalar Curvature ◽  
Evolution Equations ◽  
Initial Conditions ◽  
De Sitter ◽  
Airy Functions ◽  
Special Cases ◽  
The Universe ◽  
Current Stage

We study scalar field FLRW cosmology in the content of f(R) gravity. Our consideration is restricted to the spatially flat Friedmann universe. We derived the general evolution equations of the model, and showed that the scalar field equation is automatically satisfied for any form of the f(R) function. We also derived representations for kinetic and potential energies, as well as for the acceleration in terms of the Hubble parameter and the form of the f(R) function. Next we found the exact cosmological solutions in modified gravity without specifying the f(R) function. With negligible acceleration of the scalar curvature, we found that the de Sitter inflationary solution is always attained. Also we obtained new solutions with special restrictions on the integration constants. These solutions contain oscillating, accelerating, decelerating and even contracting universes. For further investigation, we selected special cases which can be applied with early or late inflation. We also found exact solutions for the general case for the model with negligible acceleration of the scalar curvature in terms of special Airy functions. Using initial conditions which represent the universe at the present epoch, we determined the constants of integration. This allows for the comparison of the scale factor in the new solutions with that for current stage of the universe evolution in the [Formula: see text]CDM model.

Phases in holographic helical superconductor

2017 ◽  
Vol 32 (13) ◽  
pp. 1750064 ◽  
Author(s):  
Subir Mukhopadhyay ◽  
Chandrima Paul
Keyword(s):  
Gauge Theory ◽  
Critical Temperature ◽  
Scalar Field ◽  
Helical Structure ◽  
P Wave ◽  
Back Reaction ◽  
Free Energies ◽  
S Wave ◽  
Abelian Gauge ◽  
Chern Simons

We study SU(2)[Formula: see text]×[Formula: see text]U(1) gauge theory with Chern–Simons term, coupled to scalar field in adjoint, in a probe approximation by ignoring back reaction on metric. Considering a simple ansatz for non-Abelian gauge field with helical structure, we find it admits s-wave and p-wave phases along with their coexistence. We study free energies for different phases along with those for p-wave phases for different values of pitch and frequency dependence of optical conductivities below critical temperature.

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