292,378 research outputs found
Continuous variable entanglement of phase locked light beams
We explore in detail the possibility of intracavity generation of
continuous-variable (CV) entangled states of light beams under mode
phase-locked conditions. We show that such quantum states can be generated in
self-phase locked nondegenerate optical parametric oscillator (NOPO) based on a
type-II phase-matched down-conversion combined with linear mixer of two
orthogonally polarized modes of the subharmonics in a cavity. A quantum theory
of this device, recently realized in the experiment, is developed for both
sub-threshold and above-threshold operational regimes. We show that the system
providing high level phase coherence between two generated modes, unlike to the
ordinary NOPO, also exhibits different types of quantum correlations between
photon numbers and phases of these modes. We quantify the CV entanglement as
two-mode squeezing and show that the maximal degree of the integral two-mode
squeezing(that is 50% relative to the level of vacuum fluctuations) is achieved
at the pump field intensity close to the generation threshold of self-phase
locked NOPO, provided that the constant of linear coupling between the two
polarizations is much less than the mode detunings. The peculiarities of CV
entanglement for the case of unitary, non-dissipative dynamics of the system
under consideration is also cleared up
The Nature of Thermopower in Bipolar Semiconductors
The thermoemf in bipolar semiconductors is calculated. It is shown that it is
necessary to take into account the nonequilibrium distribution of electron and
hole concentrations (Fermi quasilevels of the electrons and holes). We find
that electron and hole electric conductivities of contacts of semiconductor
samples with connecting wires make a substantial contribution to thermoemf.Comment: 17 pages, RevTeX 3.0 macro packag
Cosmological evolution of the cosmological plasma with interpartial scalar interaction. II. Formulation of mathematical model
On the basis of the relativistic kinetic theory the relativistic statistical
systems with scalar interaction particles are investigated. The self-consistent
system of the equations describing self-gravitating plasma with interpartial
scalar interaction is formulated, macroscopical laws of preservation are
received. The closed system of the equations describing cosmological models to
which the matter is presented by plasma with interpartial scalar interaction is
received.Comment: 12 pages, 9 reference
Negative eigenvalues of the Ricci operator of solvable metric Lie algebras
In this paper we get a necessary and sufficient condition for the Ricci
operator of a solvable metric Lie algebra to have at least two negative
eigenvalues. In particular, this condition implies that the Ricci operator of
every non-unimodular solvable metric Lie algebra or every non-abelian nilpotent
metric Lie algebra has this property.Comment: 16 pages, minor correction
Generalized Model of Migration-Driven Aggregate Growth - Asymptotic Distributions, Power Laws and Apparent Fractality
The rate equation for exchange-driven aggregation of monomers between
clusters of size by power-law exchange rate (), where
detaching and attaching processes were considered separately, is reduced to
Fokker-Planck equation. Its exact solution was found for unbiased aggregation
and agreed with asymptotic conclusions of other models. Asymptotic transitions
were found from exact solution to Weibull/normal/exponential distribution, and
then to power law distribution. Intermediate asymptotic size distributions were
found to be functions of exponent and vary from normal ()
through Weibull () to exponential () ones, that gives the
new system for linking these basic statistical distributions. Simulations were
performed for the unbiased aggregation model on the basis of the initial rate
equation without simplifications used for reduction to Fokker-Planck equation.
The exact solution was confirmed, shape and scale parameters of Weibull
distribution (for ) were determined by analysis of cumulative
distribution functions and mean cluster sizes, which are of great interest,
because they can be measured in experiments and allow to identify details of
aggregation kinetics (like ). In practical sense, scaling analysis of
\emph{evolving series} of aggregating cluster distributions can give much more
reliable estimations of their parameters than analysis of \emph{solitary}
distributions. It is assumed that some apparent power and fractal laws observed
experimentally may be manifestations of such simple migration-driven
aggregation kinetics even.Comment: 11 pages, 7 figure
- …
