5,904 research outputs found
Reissner-Nordstrom-like solutions of the SU(2) Einstein-Yang/Mills (EYM) equations
In this paper we study a new type of solution of the spherically symmetric,
Einstein-Yang/Mills (EYM) equations with SU(2) gauge group. These solutions are
well-behaved in the far-field, and have a Reissner-Nordstrom type essential
singularity at the origin. These solutions display some novel features which
are not present in particle-like, or black-hole solutions. Any spherically
symmetric solution to the EYM equations, defined in the far-field, is either a
particle-like solution, a black-hole solution, or one of these RNL solutions.Comment: 5 pages, latex, no figures, Submitted to Comm. Math. Phys. January
15, 199
Theory of transient spectroscopy of multiple quantum well structures
A theory of the transient spectroscopy of quantum well (QW) structures under
a large applied bias is presented. An analytical model of the initial part of
the transient current is proposed. The time constant of the transient current
depends not only on the emission rate from the QWs, as is usually assumed, but
also on the subsequent carrier transport across QWs. Numerical simulation was
used to confirm the validity of the proposed model, and to study the transient
current on a larger time scale. It is shown that the transient current is
influenced by the nonuniform distribution of the electric field and related
effects, which results in a step-like behavior of the current. A procedure of
extraction of the QW emission time from the transient spectroscopy experiments
is suggested.Comment: 5 pages, 4 figures, to be published in J. Appl. Phy
Noiseless Collective Motion out of Noisy Chaos
We consider the effect of microscopic external noise on the collective motion
of a globally coupled map in fully desynchronized states. Without the external
noise a macroscopic variable shows high-dimensional chaos distinguishable from
random motion. With the increase of external noise intensity, the collective
motion is successively simplified. The number of effective degrees of freedom
in the collective motion is found to decrease as with the
external noise variance . It is shown how the microscopic noise can
suppress the number of degrees of freedom at a macroscopic level.Comment: 9 pages RevTex file and 4 postscript figure
The study of initial permeability temperature dependences for LiTiZn ferrite ceramics
Results of obtaining and analyzing the temperature dependences of initial permeability of ferrite ceramics are presented in the paper. It was shown that the level of the defective state of ferrite ceramics can be obtained from the value of two parameters [alpha] and [beta] of the phenomenological expression describing the experimental dependences. The results showed that the main criterion of the defect state is the parameter [beta]/[alpha], which is related to the elastic stresses in the material. An indicator of the structure perfection is also the value of the maximum of the initial permeability near the Curie temperature
Scattering into Cones and Flux across Surfaces in Quantum Mechanics: a Pathwise Probabilistic Approach
We show how the scattering-into-cones and flux-across-surfaces theorems in
Quantum Mechanics have very intuitive pathwise probabilistic versions based on
some results by Carlen about large time behaviour of paths of Nelson
diffusions. The quantum mechanical results can be then recovered by taking
expectations in our pathwise statements.Comment: To appear in Journal of Mathematical Physic
Three-body correlations in direct reactions: Example of Be populated in reaction
The Be continuum states were populated in the charge-exchange reaction
H(Li,Be) collecting very high statistics data ( events) on the three-body ++ correlations. The
Be excitation energy region below MeV is considered, where the
data are dominated by contributions from the and states. It is
demonstrated how the high-statistics few-body correlation data can be used to
extract detailed information on the reaction mechanism. Such a derivation is
based on the fact that highly spin-aligned states are typically populated in
the direct reactions.Comment: submitted to Physical Review
Lyapunov Mode Dynamics in Hard-Disk Systems
The tangent dynamics of the Lyapunov modes and their dynamics as generated
numerically - {\it the numerical dynamics} - is considered. We present a new
phenomenological description of the numerical dynamical structure that
accurately reproduces the experimental data for the quasi-one-dimensional
hard-disk system, and shows that the Lyapunov mode numerical dynamics is linear
and separate from the rest of the tangent space. Moreover, we propose a new,
detailed structure for the Lyapunov mode tangent dynamics, which implies that
the Lyapunov modes have well-defined (in)stability in either direction of time.
We test this tangent dynamics and its derivative properties numerically with
partial success. The phenomenological description involves a time-modal linear
combination of all other Lyapunov modes on the same polarization branch and our
proposed Lyapunov mode tangent dynamics is based upon the form of the tangent
dynamics for the zero modes
On the susceptibility function of piecewise expanding interval maps
We study the susceptibility function Psi(z) associated to the perturbation
f_t=f+tX of a piecewise expanding interval map f. The analysis is based on a
spectral description of transfer operators. It gives in particular sufficient
conditions which guarantee that Psi(z) is holomorphic in a disc of larger than
one. Although Psi(1) is the formal derivative of the SRB measure of f_t with
respect to t, we present examples satisfying our conditions so that the SRB
measure is not Lipschitz.*We propose a new version of Ruelle's conjectures.* In
v2, we corrected a few minor mistakes and added Conjectures A-B and Remark 4.5.
In v3, we corrected the perturbation (X(f(x)) instead of X(x)), in particular
in the examples from Section 6. As a consequence, Psi(z) has a pole at z=1 for
these examples.Comment: To appear Comm. Math. Phy
Perturbation theory for self-gravitating gauge fields I: The odd-parity sector
A gauge and coordinate invariant perturbation theory for self-gravitating
non-Abelian gauge fields is developed and used to analyze local uniqueness and
linear stability properties of non-Abelian equilibrium configurations. It is
shown that all admissible stationary odd-parity excitations of the static and
spherically symmetric Einstein-Yang-Mills soliton and black hole solutions have
total angular momentum number , and are characterized by
non-vanishing asymptotic flux integrals. Local uniqueness results with respect
to non-Abelian perturbations are also established for the Schwarzschild and the
Reissner-Nordstr\"om solutions, which, in addition, are shown to be linearly
stable under dynamical Einstein-Yang-Mills perturbations. Finally, unstable
modes with are also excluded for the static and spherically
symmetric non-Abelian solitons and black holes.Comment: 23 pages, revtex, no figure
- …