292,378 research outputs found

    Continuous variable entanglement of phase locked light beams

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    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

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    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

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    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

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    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

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    The rate equation for exchange-driven aggregation of monomers between clusters of size nn by power-law exchange rate (nα\sim{n}^\alpha), 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 α\alpha and vary from normal (α=0\alpha=0) through Weibull (0<α<10<\alpha<1) to exponential (α=1\alpha=1) 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 0<α<10<\alpha<1) 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 α\alpha). 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
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