scholarly journals Orbital fingerprints of ultralight scalar fields around black holes

2017 ◽  
Vol 96 (8) ◽  
Author(s):  
Miguel C. Ferreira ◽  
Caio F. B. Macedo ◽  
Vitor Cardoso
Keyword(s):  
Black Holes ◽  
Scalar Fields

scholarly journals On Mass Spectra of Primordial Black Holes

2021 ◽  
Vol 8 ◽  
Author(s):  
Alexander A. Kirillov ◽  
Sergey G. Rubin
Keyword(s):  
Black Holes ◽  
Mass Spectrum ◽  
Mass Spectra ◽  
Scalar Fields ◽  
Small Mass ◽  
Primordial Black Holes ◽  
Classical Motion ◽  
Multiple Production ◽  
Analytical Formulas ◽  
Intrinsic Feature

Evidence for the primordial black holes (PBH) presence in the early Universe renews permanently. New limits on their mass spectrum challenge existing models of PBH formation. One of the known models is based on the closed walls collapse after the inflationary epoch. Its intrinsic feature is the multiple production of small mass PBH which might contradict observations in the nearest future. We show that the mechanism of walls collapse can be applied to produce substantially different PBH mass spectra if one takes into account the classical motion of scalar fields together with their quantum fluctuations at the inflationary stage. Analytical formulas have been developed that contain both quantum and classical contributions.

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 On-axis scattering of scalar fields by charged rotating black holes

2019 ◽  
Vol 795 ◽  
pp. 496-501 ◽  
Author(s):  
Luiz C. S. Leite ◽  
Carolina L. Benone ◽  
Luís C. B. Crispino
Keyword(s):  
Black Holes ◽  
Scalar Fields ◽  
Rotating Black Holes

scholarly journals Massless scalar fields and topological black holes

2000 ◽  
Vol 61 (8) ◽  
Author(s):  
Tekin Dereli ◽  
Yuri N. Obukhov
Keyword(s):  
Black Holes ◽  
Scalar Fields ◽  
Massless Scalar

scholarly journals Quasistationary solutions of self-gravitating scalar fields around black holes

2015 ◽  
Vol 91 (4) ◽  
Author(s):  
Nicolas Sanchis-Gual ◽  
Juan Carlos Degollado ◽  
Pedro J. Montero ◽  
José A. Font
Keyword(s):  
Black Holes ◽  
Scalar Fields ◽  
Quasistationary Solutions

Stationary bound states of massless scalar fields around black holes and black hole analogues

2015 ◽  
Vol 24 (09) ◽  
pp. 1542018 ◽  
Author(s):  
Carolina L. Benone ◽  
Luís C. B. Crispino ◽  
Carlos A. R. Herdeiro ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Spatial Distribution ◽  
Scalar Field ◽  
Bound States ◽  
Neumann Boundary ◽  
Mass Term ◽  
Scalar Fields ◽  
Massless Scalar ◽  
Field System

We discuss stationary bound states, a.k.a. clouds, for a massless test scalar field around Kerr black holes (BHs) and spinning acoustic BH analogues. In view of the absence of a mass term, the trapping is achieved via enclosing the BH — scalar field system in a cavity and imposing Dirichlet or Neumann boundary conditions. We discuss the variation of these bounds states with the discrete parameters that label them, as well as their spatial distribution, complementing results in our previous work [C. L. Benone, L. C. B. Crispino, C. Herdeiro and E. Radu, Phys. Rev. D91 (2015) 104038].

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