scholarly journals No hair for spherically symmetric neutral black holes: Nonminimally coupled massive scalar fields

2017 ◽  
Vol 96 (12) ◽  
Author(s):  
Shahar Hod
Keyword(s):  
Black Holes ◽  
Scalar Fields ◽  
Spherically Symmetric ◽  
Massive Scalar

scholarly journals Instability of charged massive scalar fields in bound states around Kerr–Sen black holes

2015 ◽  
Vol 24 (14) ◽  
pp. 1550102 ◽  
Author(s):  
Haryanto M. Siahaan
Keyword(s):  
Black Holes ◽  
Bound States ◽  
Gordon Equation ◽  
Scalar Fields ◽  
Bound State ◽  
Imaginary Component ◽  
Scalar Perturbation ◽  
Massive Scalar ◽  
Massive Scalar Field ◽  
Klein Gordon

In this paper, we show the instability of a charged massive scalar field in bound states around Kerr–Sen black holes. By matching the near and far region solutions of the radial part in the corresponding Klein–Gordon equation, one can show that the frequency of bound state scalar fields contains an imaginary component which gives rise to an amplification factor for the fields. Hence, the unstable modes for a charged and massive scalar perturbation in Kerr–Sen background can be shown.

scholarly journals Quasi-black holes: General features and purely field configurations

2015 ◽  
Vol 30 (30) ◽  
pp. 1550154 ◽  
Author(s):  
K. A. Bronnikov ◽  
O. B. Zaslavskii
Keyword(s):  
Black Holes ◽  
Small Parameter ◽  
Exact Solutions ◽  
Scalar Fields ◽  
Spherically Symmetric ◽  
Material Source

Objects that are on the threshold of forming the horizon but never collapse are called quasi-black holes (QBHs). We discuss the properties of the general spherically symmetric QBH metric without addressing its material source, including its limiting cases as the corresponding small parameter tends to zero. We then show that QBHs can exist among self-gravitating configurations of electromagnetic and dilatonic scalar fields without matter. These general results are illustrated by explicit examples of exact solutions.

Some interactions of spherically symmetric massive scalar field with Brans–Dicke scalar field in Robertson–Walker universe

2019 ◽  
Vol 16 (04) ◽  
pp. 1950066 ◽  
Author(s):  
Kangujam Priyokumar Singh ◽  
Rajshekhar Roy Baruah
Keyword(s):  
Scalar Field ◽  
Cosmic Time ◽  
Scalar Fields ◽  
Cosmological Term ◽  
Physical Parameters ◽  
Spherically Symmetric ◽  
Massive Scalar ◽  
Field Equations ◽  
Massive Scalar Field ◽  
The Universe

Here in this work, we investigated the possible cosmological consequences of the interaction of Brans–Dicke scalar field and massive scalar field by considering spherically symmetric Robertson–Walker metric. The present problem can also be treated as an extension work of [K. Priyokumar et al., Interaction of gravitational field and Brans–Dicke field, Res. Astron. Astrophys. 16(4) (2016) 64; K. Priyokumar and M. Dewri, Interaction of electromagnetic field and Brans–Dicke field, Chinease J. Phys. 54 (2016) 845]. The exact solutions of the field equations are obtained with seven different cases. The behavior of the model and their contribution to the process of the evolution are examined in detail from some explicit and reasonable values of free parameter. We also presented the variations of certain physical parameters versus cosmic time graphically to compare our solutions with the present observational findings. When we studied further, it is found that the cosmological term [Formula: see text] takes a great role in the accelerating expansion of our universe when both scalar fields are exponentially increasing functions of time, while the cosmological term will not appear in the case when both the scalar fields are exponentially decreasing functions of time. Also, the scalar field is seen to have a tendency to increase the expansion of the universe, thereby flattening the universe.

scholarly journals Asymptotic quasinormal modes of string-theoretical d-dimensional black holes

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Filipe Moura ◽  
João Rodrigues
Keyword(s):  
Differential Equation ◽  
Black Holes ◽  
Complex Plane ◽  
Quasinormal Modes ◽  
Scalar Fields ◽  
Einstein Gravity ◽  
Quasinormal Mode ◽  
Spherically Symmetric ◽  
Gravitational Perturbations

Abstract We compute the quasinormal frequencies of d-dimensional spherically symmetric black holes with leading string α′ corrections for tensorial gravitational perturbations in the highly damped regime. We solve perturbatively the master differential equation and we compute the monodromies of the master perturbation variable (analytically continued to the complex plane) in different contours, in order to obtain the quasinormal mode spectra. We proceed analogously for the quasinormal modes of test scalar fields. Differently than in Einstein gravity, we obtain distinct results for the two cases.

scholarly journals Spherically Symmetric Configurations in General Relativity in the Presence of a Linear Massive Scalar Field: Separation of a Distribution of Test Body Circular Orbits

2019 ◽  
Vol 64 (3) ◽  
pp. 189 ◽  
Author(s):  
O. S. Stashko ◽  
V. I. Zhdanov
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Scalar Fields ◽  
Test Body ◽  
Einstein Equations ◽  
Strength Parameter ◽  
Spherically Symmetric ◽  
Massive Scalar ◽  
Circular Orbits ◽  
Massive Scalar Field

We study static spherically symmetric configurations in the presence of linear massive scalar fields within General Relativity. Static solutions of the Einstein equations are considered under conditions of asymptotic flatness. Each solution is fixed by the configuration mass and the field strength parameter, which are defined at spatial infinity. The metric coefficients and the scalar field for a specific configuration are obtained numerically. Then we study the time-like geodesics describing the test particle motion. The focus is on the distribution of stable circular orbits (SCOs) of the test particles around a configuration. We found that, for the continuum of configuration parameters, there exist two unlinked regions of SCOs that are separated by some annular region, where SCOs do not exist.

S-MATRICES FOR QUANTUM CHARGED MASSIVE SCALAR PARTICLES ON SCHWARZSCHILD AND REISSNER–NORDSTRÖM BLACK HOLES

2000 ◽  
Vol 09 (01) ◽  
pp. 79-89 ◽  
Author(s):  
N. E. FIRSOVA
Keyword(s):  
Black Holes ◽  
Hawking Radiation ◽  
Scalar Fields ◽  
Massive Scalar ◽  
Numerical Computations ◽  
Scattering Problems ◽  
Complex Scalar ◽  
Scalar Particles

We study the scattering problems arising when considering the contribution of the topologically inequivalent configurations (TICs) of the massive complex scalar fields on Schwarzschild and Reissner–Nordström black holes to the Hawking radiation. The corresponding S-matrices are explored and presented in the form convenient to numerical computations.

Stationary configurations around charged rotating black holes

2016 ◽  
Vol 25 (09) ◽  
pp. 1641012
Author(s):  
Carolina L. Benone
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Bound States ◽  
Scalar Fields ◽  
Analytic Solutions ◽  
Massive Scalar ◽  
Massive Scalar Field ◽  
Rotating Black Holes ◽  
Specific Frequency

Scalar fields can form real bound states around black holes for a specific frequency. In this work, we review the case of a charged and massive scalar field around a charged rotating black hole, in order to find these bound states. We analyze the behavior of these solutions for different parameters and also comment on analytic solutions for certain regimes.

Sign in / Sign up

Export Citation Format

Share Document