3,544 research outputs found
Thermonuclear burn-up in deuterated methane
The thermonuclear burn-up of highly compressed deuterated methane CD is
considered in the spherical geometry. The minimal required values of the
burn-up parameter are determined for various
temperatures and densities . It is shown that thermonuclear burn-up
in becomes possible in practice if its initial density exceeds
. Burn-up in CDT methane
requires significantly ( 100 times) lower compressions. The developed
approach can be used in order to compute the critical burn-up parameters in an
arbitrary deuterium containing fuel
Scattering of Straight Cosmic Strings by Black Holes: Weak Field Approximation
The scattering of a straight, infinitely long string moving with velocity
by a black hole is considered. We analyze the weak-field case, where the impact
parameter () is large, and obtain exact solutions to the equations of
motion. As a result of scattering, the string is displaced in the direction
perpendicular to the velocity by an amount , where . The second
term dominates at low velocities . The late-time
solution is represented by a kink and anti-kink, propagating in opposite
directions at the speed of light, and leaving behind them the string in a new
``phase''. The solutions are applied to the problem of string capture, and are
compared to numerical results.Comment: 19 pages, 5 figure
Accretion of non-minimally coupled generalized Chaplygin gas into black holes
The mass evolution of Schwarzschild black holes by the absorption of scalar
fields is investigated in the scenario of the generalized Chaplygin gas (GCG).
The GCG works as a unification picture of dark matter plus dark energy that
naturally accelerates the expansion of the Universe. Through elements of the
quasi-stationary approach, we consider the mass evolution of Schwarzschild
black holes accreted by non-minimally coupled cosmological scalar fields
reproducing the dynamics of the GCG. As a scalar field non-minimally coupled to
the metrics, such an exotic content has been interconnected with accreting
black holes. The black hole increasing masses by the absorption of the gas
reflects some consistence of the accretion mechanism with the hypothesis of the
primordial origin of supermassive black holes. Our results effectively show
that the non-minimal coupling with the GCG dark sector accelerates the
increasing of black hole masses. Meanwhile some exotic features can also be
depicted for specific ranges of the non-minimal coupling in which the GCG
dynamics is substantially modified.Comment: 13 pages, 03 figure
Small deviations of iterated processes in space of trajectories
We derive logarithmic asymptotics of probabilities of small deviations for
iterated processes in the space of trajectories. We find conditions under which
these asymptotics coincide with those of processes generating iterated
processes. When these conditions fail the asymptotics are quite different
Gauge field theory for Poincar\'{e}-Weyl group
On the basis of the general principles of a gauge field theory the gauge
theory for the Poincar\'{e}-Weyl group is constructed. It is shown that tetrads
are not true gauge fields, but represent functions from true gauge fields:
Lorentzian, translational and dilatational ones. The equations of gauge fields
which sources are an energy-momentum tensor, orbital and spin momemta, and also
a dilatational current of an external field are obtained. A new direct
interaction of the Lorentzian gauge field with the orbital momentum of an
external field appears, which describes some new effects. Geometrical
interpretation of the theory is developed and it is shown that as a result of
localization of the Poincar\'{e}-Weyl group spacetime becomes a Weyl-Cartan
space. Also the geometrical interpretation of a dilaton field as a component of
the metric tensor of a tangent space in Weyl-Cartan geometry is proposed.Comment: LaTex, 27 pages, no figure
Vacuum polarization of massive scalar fields in the spacetime of the electrically charged nonlinear black hole
The approximate renormalized stress-energy tensor of the quantized massive
conformally coupled scalar field in the spacetime of electrically charged
nonlinear black hole is constructed. It is achieved by functional
differentiation of the lowest order of the DeWitt-Schwinger effective action
involving coincidence limit of the Hadamard-Minakshisundaram-DeWitt-Seely
coefficient The result is compared with the analogous result derived
for the Reissner-Nordstr\"om black hole. It is shown that the most important
differences occur in the vicinity of the event horizon of the black hole near
the extremality limit. The structure of the nonlinear black hole is briefly
studied by means of the Lambert functions.Comment: 22 pages, 10 figure
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