509 research outputs found
Quantum amplification effect in a horizon fluctuations
The appearance of a few unevenly- spaced bright flashes of light on top of
Hawking radiation is the sign of the amplification effect in black hole horizon
fluctuations. Previous studies on this problem suffer from the lack of
considering all emitted photons in the theoretical spectroscopy of these
fluctuations. In this paper, we include all of the physical transition weights
and present a consistent intensity formula. This modifies a black hole
radiation pattern.Comment: 6 pages, 2 figure
On Quantum Nature of Black-Hole Spacetime: A Possible New Source of Intense Radiation
Atoms and the planets acquire their stability from the quantum mechanical
incompatibility of the position and momentum measurements. This incompatibility
is expressed by the fundamental commutator [x, p_x]=i hbar, or equivalently,
via the Heisenberg's uncertainty principle Delta x Delta p_x sim hbar. A
further stability-related phenomenon where the quantum realm plays a dramatic
role is the collapse of certain stars into white dwarfs and neutron stars.
Here, an intervention of the Pauli exclusion principle, via the fermionic
degenerate pressure, stops the gravitational collapse. However, by the
neutron-star stage the standard quantum realm runs dry. One is left with the
problematic collapse of a black hole. This essay is devoted to a concrete
argument on why the black-hole spacetime itself should exhibit a quantum
nature. The proposed quantum aspect of spacetime is shown to prevent the
general-relativistic dictated problematic collapse. The quantum nature of
black-hole spacetime is deciphered from a recent result on the universal
equal-area spacing [=lambda_P^2 4 ln(3)] for black holes. In one interpretation
of the emergent picture, an astrophysical black hole can fluctuate to
sqrt{pi/ln(3)} approx 1.7 times its classical size, and thus allow radiation
and matter to escape to the outside observers. These fluctuations I conjecture
provide a new source, perhaps beyond Hawking radiation, of intense radiation
from astrophysical black holes and may be the primary source of observed
radiation from those galactic cores what carry black hole(s). The presented
interpretation may be used as a criterion to choose black holes from black hole
candidates.Comment: This essay received an "honorable mention" in the 1999 Essay
Competition of the Gravity Research Foundation - Ed. Int. J. Mod. Phys. D
(1999, in press). For Joseph Knech
Chern-Simons Correlations on (2+1)D Lattice
We have computed the contribution of zero modes to the value of the number of
particles in the model of discrete (2+1)-dimensional nonlinear Schr\"odinger
equation. It is shown for the first time that in the region of small values of
the Chern-Simons coefficient k there exists a universal attraction between
field configurations. For k=2 this phenomenon may be a dynamic origin of the
semion pairing in high temperature superconducting state of planar systems.Comment: 9 pages, 2 figures Sabj-class: Strongly Correlated Electron
Spectrum of Charged Black Holes - The Big Fix Mechanism Revisited
Following an earlier suggestion of the authors(gr-qc/9607030), we use some
basic properties of Euclidean black hole thermodynamics and the quantum
mechanics of systems with periodic phase space coordinate to derive the
discrete two-parameter area spectrum of generic charged spherically symmetric
black holes in any dimension. For the Reissner-Nordstrom black hole we get
, where the integer p=0,1,2,.. gives the charge
spectrum, with . The quantity , n=0,1,... gives
a measure of the excess of the mass/energy over the critical minimum (i.e.
extremal) value allowed for a given fixed charge Q. The classical critical
bound cannot be saturated due to vacuum fluctuations of the horizon, so that
generically extremal black holes do not appear in the physical spectrum.
Consistency also requires the black hole charge to be an integer multiple of
any fundamental elementary particle charge: , m=0,1,2,.... As a
by-product this yields a relation between the fine structure constant and
integer parameters of the black hole -- a kind of the Coleman big fix mechanism
induced by black holes. In four dimensions, this relationship is
and requires the fine structure constant to be a rational
number. Finally, we prove that the horizon area is an adiabatic invariant, as
has been conjectured previously.Comment: 21 pages, Latex. 1 Section, 1 Figure added. To appear in Class. and
Quant. Gravit
Trying to understand confinement in the Schroedinger picture
We study the gauge-invariant gaussian ansatz for the vacuum wave functional
and show that it potentially possesses many desirable features of the
Yang--Mills theory, like asymptotic freedom, mass generation through the
transmutation of dimensions and a linear potential between static quarks. We
point out that these (and other) features can be studied in a systematic way by
combining perturbative and 1/n expansions. Contrary to the euclidean approach,
confinement can be easily formulated and easily built in, if not derived, in
the variational Schroedinger approach.Comment: 21 pages, 1 figure. Lecture given at the 4th St.Petersburg Winter
School in Theoretical Physics, Feb. 22-28, 199
Solution of gauge theories induced by fundamental representation scalars
Gauge theories induced by scalars in the fundamental representation of the
group are investigated in the large
and limit. A master field is defined from bilinears of the scalar
field following an Eguchi-Kawai type reduction of spacetime. The density
function for the master field satisfies an integral equation that can be solved
exactly in two dimensions (D=2) and in a convergent series of approximations at
. While at D=2 the system is in the same phase at all ,
it undergoes a phase transition at a critical value, , for
.Comment: 12 pages, LaTe
SN1A data and the CMB of Modified Curvature at short and long distances
The SN1a data, although inconclusive, when combined with other observations
makes a strong case that our universe is presently dominated by dark energy. We
investigate the possibility that large distance modifications of the curvature
of the universe would perhaps offer an alternative explanation of the
observation. Our calculations indicate that a universe made up of no dark
energy but instead, with a modified curvature at large scales, is not
scale-invariant, therefore quite likely it is ruled out by the CMB
observations. The sensitivity of the CMB spectrum is checked for the whole
range of mode modifications of large or short distance physics. The spectrum is
robust against modifications of short-distance physics and the UV cutoff when:
the initial state is the adiabatic vacuum, and the inflationary background
space is de Sitter.Comment: 13 pages, 2 eps figures, typos corrected, references added; to appear
in Phys. Rev.
Relativistic parsec-scale jets: I. Particle acceleration
We develop a theory of particle acceleration inside relativistic rotating
electron-positron force-free jets with spiral magnetic fields. We considered
perturbation of the stationary magnetic field structure and found that
acceleration takes place in the regions where the Alfven resonant condition
with the eigenmodes in the jet is fulfilled, i.e. where the local Alfven speed
is equal to the phase speed of an eigenmode. The acceleration mechanism is
regular acceleration by the electric field of the electromagnetic wave, which
is the eigenmode of the force-free cylindrical jet: particles drift out of the
region of the large wave amplitude near the Alfven resonant surface and gain
energy. Acceleration in the strong electric field near the Alfven resonance and
synchrotron losses combine to form a power-law energy spectrum of
ultra-relativistic electrons and positrons with index between 2 and 3 depending
upon the initial energy of the injected particles. The power law distribution
ranges from 10 MeV to 1000 MeV.Comment: 14 pages, 4 figures; Astron. Astrophys. in pres
Resistivity and 1/f Noise in Non-Metallic Phase Separated Manganites
A simple model is proposed to calculate resistivity, magnetoresistance, and
noise spectrum in non-metallic phase-separated manganites containing small
metallic droplets (magnetic polarons). The system is taken to be far from the
percolation transition into a metallic state. It is assumed that the charge
transfer occurs due to electron tunneling from one droplet to another through
the insulating medium. As a result of this tunneling, the droplets acquire or
lose extra electrons forming metastable two-electron and empty states. In the
framework of this model, explicit expressions for dc conductivity and noise
power of the system are derived. It is shown that the noise spectrum has 1/f
form in the low-frequency range.Comment: 6 pages, 1 fugure include
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