Covariant Treatment of Neutrino Spin (Flavour) Conversion in Matter under the Influence of Electromagnetic Fields

Within the recently proposed Lorentz invariant formalism for description of neutrino spin evolution in presence of an arbitrary electromagnetic fields effects of matter motion and polarization are considered.Comment: Extended version of contribution to "Particle Physics on Boundary of Millenniums" (Proceedings of the 9th Lomonosov Conference on Elementary Particle Physics, World Scientific, Singapure

Dark matter implications of the WMAP-Planck Haze

Gamma rays and microwave observations of the Galactic Center and surrounding areas indicate the presence of anomalous emission, whose origin remains ambiguous. The possibility of dark matter (DM) annihilation explaining both signals through prompt emission at gamma-rays and secondary emission at microwave frequencies from interactions of high-energy electrons produced in annihilation with the Galactic magnetic fields has attracted much interest in recent years. We investigate the DM interpretation of the Galactic Center gamma-ray excess by searching for the associated synchrotron in the WMAP-Planck data. Considering various magnetic field and cosmic-ray propagation models, we predict the synchrotron emission due to DM annihilation in our Galaxy, and compare it with the WMAP-Planck data at 23-70GHz. In addition to standard microwave foregrounds, we separately model the microwave counterpart to the Fermi Bubbles and the signal due to DM, and use component separation techniques to extract the signal associated with each template from the total emission. We confirm the presence of the Haze at the level of 7% of the total sky intensity at 23GHz in our chosen region of interest, with a harder spectrum $I \sim \nu^{-0.8}$ than the synchrotron from regular cosmic-ray electrons. The data do not show a strong preference towards fitting the Haze by either the Bubbles or DM emission only. Inclusion of both components provides a better fit with a DM contribution to the Haze emission of 20% at 23GHz, however, due to significant uncertainties in foreground modeling, we do not consider this a clear detection of a DM signal. We set robust upper limits on the annihilation cross section by ignoring foregrounds, and also report best-fit DM annihilation parameters obtained from a complete template analysis. We conclude that the WMAP-Planck data are consistent with a DM interpretation of the gamma-ray excess.Comment: 34 pages, 9 figure

Instability-induced formation and non-equilibrium dynamics of phase defects in polariton condensates

We study, theoretically and numerically, the onset and development of modulational instability in an incoherently pumped spatially homogeneous polariton condensate. Within the framework of mean-field theory, we identify regimes of modulational instability in two cases: 1) Strong feedback between the condensate and reservoir, which may occur in scalar condensates, and 2) Parametric scattering in the presence of polarization splitting in spinor condensates. In both cases we investigate the instability induced textures in space and time including non-equilibrium dynamics of phase dislocations and vortices. In particular we discuss the mechanism of vortex destabilization and formation of spiraling waves. We also identify the presence of topological defects, which take the form of half-vortex pairs in the spinor case, giving an "eyelet" structure in intensity and dipole type structure in the spin polarization. In the modulationally stable parameter domains, we observe formation of the phase defects in the process of condensate formation from an initially spatially incoherent low-density state. In analogy to the Kibble-Zurek type scaling for nonequilibrium phase transitions, we find that the defect density scales with the pumping rate.Comment: 13 pages, 9 figures, revised manuscript sent to Phys. Rev.

Ion Association Effects of Lipophilic Quaternary Ammonium Salts in Ion-Exchange and Potentiometric Selectivity

Strong effects of ion association on the anion-exchange selectivity in systems water -solutions of high quaternary ammonium salts (QAS) in organic solvents as well as on the potentiometric selectivity of plasticized polyvinylchloride (PVC) membranes containing QAS as ion exchangers have been established experimen¬tally and substantiated theoretically. Based on the linear Gibbs energy relations (LGER) and ion association theory by Eigen-Denison-Ramsey-Fuoss, an approach to separate estimation of the parts played by the solvation and ion association fac¬tors in ion-exchange and potentiometric selectivity has been proposed. The results obtained serve as the basis for revision of the formed notions about QAS as of «nonselective» ion exchangers and enable the development of methods for the con¬trol of ion-exchange and potentiometric selectivity using the factor of ion associa¬tion. Specifically, it has been demonstrated that variation of steric accessibility of the QAS exchange center is a powerful means to control the selectivity. It has been found experimentally that due to varying steric accessibility of the QAS exchange center the selectivity values have changed by 3 orders of magnitu¬de in case of single- charged anions exchanged for single-charged ones and by more than 7 orders - in case of double-charged anions exchanged for the sing¬le-charged ones. The above-mentioned effects revealed also in the potentiometric selectivity of QAS-based PVC membranes and to some extent - in the potentiometric selectivity of the membranes based on neutral anion carriers, doped with QAS for provision of anion permselectivity, are of great practical importance for the development of ISE with improved selectivity

Analysis of Transient Processes in a Radiophysical Flow System

Transient processes in a third-order radiophysical flow system are studied and a map of the transient process duration versus initial conditions is constructed and analyzed. The results are compared to the arrangement of submanifolds of the stable and unstable cycles in the Poincare section of the system studied.Comment: 3 pages, 2 figure