Scattering of gravitational radiation by a Schwarzschild black-hole.

Department of Physics, New York University, New York, NY 10012, USA.
Nature (Impact Factor: 42.35). 09/1970; 227(5261):936-8. DOI: 10.1038/227936a0
Source: PubMed

ABSTRACT THE discovery of pulsars and the general conviction that they are
neutron stars resulting from gravitational collapse have strengthened
the belief in the possible presence of Schwarzschild black-holes-or
Schwarzschild horizons-in nature, the latter being the ultimate stage in
the progressive spherical collapse of a massive star. The stability of
these objects, which has been discussed in a recent report1,
ensures their continued existence after formation. Inasmuch as the
infinite redshift associated with it and its behaviour as a one-way
membrane make the Schwarzschild horizon at once elusive and intriguing,
it is important to explore theoretically all possible modes in which the
presence of such a black-hole manifests itself. In what follows, we
present a partial summary of some results obtained from an investigation
of the scattering of gravitational waves by a Schwarzschild horizon.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Superradiance is a radiation enhancement process that involves dissipative systems. With a 60 year-old history, superradiance has played a prominent role in optics, quantum mechanics and especially in relativity and astrophysics. In General Relativity, black-hole superradiance is permitted by dissipation at the event horizon, that allows for energy and angular momentum extraction from the vacuum, even at the classical level. Black-hole superradiance is intimately connected to the black-hole area theorem, Penrose process, tidal forces and even Hawking radiation, which can be interpreted as a quantum version of black-hole superradiance. Various mechanisms (as diverse as massive fields, magnetic fields, anti-de Sitter boundaries, nonlinear interactions, etc...) can confine the amplified radiation and give rise to strong instabilities. These "black-hole bombs" have applications in searches of dark matter and of physics beyond the Standard Model, are associated to the threshold of formation of new black hole solutions that evade the no-hair theorems, can be studied in the laboratory by devising analog models of gravity, and even provide a holographic description of spontaneous symmetry breaking and superfluidity through the gauge-gravity duality. This work is meant to provide a unified picture of this multifaceted subject, which was missing in the literature. We focus on the recent developments in the field, and work out a number of novel examples and applications, ranging from fundamental physics to astrophysics.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The quasinormal modes of massless scalar field perturbation of the Reissner-Nordström de Sitter black hole with a global monopole is investigated using the 6th order WKB method. The results show that the magnitude of the real part of the quasinormal frequencies decreases, while the magnitude of the imaginary one increases as b (related to η) – the scale factor of symmetry-broking) increases for fixed angular harmonic index l, overtone index n, cosmological constant Λ and charge Q. For fixed l, n, Λ, and b, the damping of massless scalar field in the space-time of the Reissner-Nordström de Sitter black hole with a global monopole faster and faster at first and afterwards becomes slower and slower with the increase of Q when the cosmological constant Λ is smaller, while the cosmological constant Λ is larger, the damping becomes faster and faster all the way with the increase of Q.
    General Relativity and Gravitation 05/2014; 5(5). DOI:10.1007/s10714-014-1728-9 · 1.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We investigate the generation of electromagnetic and gravitational radiation in the vicinity of a perturbed Schwarzschild black hole. The gravitational perturbations and the electromagnetic field are studied by solving the Teukolsky master equation with sources, which we take to be locally charged, radially infalling, matter. Our results show that, in addition to the gravitational wave generated as the matter falls into the black hole, there is also a burst of electromagnetic radiation. This electromagnetic field has a characteristic set of quasinormal frequencies, and the gravitational radiation has the quasinormal frequencies of a Schwarzschild black hole. This scenario allows us to compare the gravitational and electromagnetic signals that are generated by a common source.
    General Relativity and Gravitation 10/2014; 46(11). DOI:10.1007/s10714-014-1819-7 · 1.73 Impact Factor