9,844 research outputs found
Black hole lasers, a mode analysis
We show that the black hole laser effect discovered by Corley & Jacobson
should be described in terms of frequency eigenmodes that are spatially bound.
The spectrum contains a discrete and finite set of complex frequency modes
which appear in pairs and which encode the laser effect. In addition, it
contains real frequency modes that form a continuous set when space is
infinite, and which are only elastically scattered, i.e., not subject to any
Bogoliubov transformation. The quantization is straightforward, but the
calculation of the asymptotic fluxes is rather involved. When the number of
complex frequency modes is small, our expressions differ from those given
earlier. In particular, when the region between the horizons shrinks, there is
a minimal distance under which no complex frequency mode exists, and no
radiation is emitted. Finally, we relate this effect to other dynamical
instabilities found for rotating black holes and in electric fields, and we
give the conditions to get this type of instability.Comment: 19 pages, 3 figures, main changes: new figure and new Sec.6
`conditions for having a laser effect', final version accepted in PR
Massless and Massive Monopoles Carrying Nonabelian Magnetic Charges
The properties of BPS monopoles carrying nonabelian magnetic charges are
investigated by following the behavior of the moduli space of solutions as the
Higgs field is varied from a value giving a purely abelian symmetry breaking to
one that leaves a nonabelian subgroup of the gauge symmetry unbroken. As the
limit of nonabelian unbroken symmetry is reached, some of the fundamental
abelian monopoles remain massive but acquire nonabelian magnetic charges. The
BPS mass formula indicates that others should because massless in this limit.
These do not correspond to distinct solitons, but instead are manifested as a
``nonabelian cloud'' surrounding the massive monopoles, with their position and
phase degrees of freedom being transformed into parameters characterizing the
cloud.Comment: 17 pages Latex, presented at Quarks-96, Yaroslavl, Russi
Metastable states of surface plasmon vacuum near the interface between metal and nonlinear dielectric
Zero-point fluctuations of surface plasmon modes near the interface between
metal and nonlinear dielectric are shown to produce a thin layer of altered
dielectric constant near the interface. This effect may be sufficiently large
to produce multiple metastable states of the surface plasmon vacuum.Comment: 4 pages, 2 figure
Gauge invariant plane-wave solutions in supersymmetric Yang-Mills quantum mechanics
We derive the spectra of D=2, SU(3) supersymmetric Yang-Mills quantum
mechanics in all fermionic sectors. Moreover, we provide exact expressions for
the corresponding eigenvectors in the sectors with none and one fermionic
quantum. We also generalize our results obtained in a cut Fock space to the
infinite cut-off limit.Comment: 38 pages, 1 figur
Hawking Radiation from Feynman Diagrams
The aim of this letter is to clarify the relationships between Hawking
radiation and the scattering of light by matter falling into a black hole. To
this end we analyze the S-matrix elements of a model composed of a massive
infalling particle (described by a quantized field) and the radiation field.
These fields are coupled by current-current interactions and propagate in the
Schwarzschild geometry. As long as the photons energy is much smaller than the
mass of the infalling particle, one recovers Hawking radiation since our
S-matrix elements identically reproduce the Bogoliubov coefficients obtained by
treating the trajectory of the infalling particle classically. But after a
brief period, the energy of the `partners' of Hawking photons reaches this mass
and the production of thermal photons through these interactions stops. The
implications of this result are discussed.Comment: 12 pages, revtex, no figure
- …