Size-dependence of Strong-Coupling Between Nanomagnets and Photonic Cavities

The coherent dynamics of a coupled photonic cavity and a nanomagnet is explored as a function of nanomagnet size. For sufficiently strong coupling eigenstates involving highly entangled photon and spin states are found, which can be combined to create coherent states. As the size of the nanomagnet increases its coupling to the photonic mode also monotonically increases, as well as the number of photon and spin states involved in the system's eigenstates. For small nanomagnets the crystalline anisotropy of the magnet strongly localized the eigenstates in photon and spin number, quenching the potential for coherent states. For a sufficiently large nanomagnet the macrospin approximation breaks down and different domains of the nanomagnet may couple separately to the photonic mode. Thus the optimal nanomagnet size is just below the threshold for failure of the macrospin approximation.Comment: 10 pages, 7 figure

Quadrupole collective modes in trapped finite-temperature Bose-Einstein condensates

Finite temperature simulations are used to study quadrupole excitations of a trapped Bose-Einstein condensate. We focus specifically on the m=0 mode, where a long-standing theoretical problem has been to account for an anomalous variation of the mode frequency with temperature. We explain this behavior in terms of the excitation of two separate modes, corresponding to coupled motion of the condensate and thermal cloud. The relative amplitudes of the modes depends sensitively on the temperature and on the frequency of the harmonic drive used to excite them. Good agreement with experiment is found for appropriate drive frequencies.Comment: 4 pages, 3 figure

SDSS J131339.98+515128.3: A new gravitationally lensed quasar selected based on near-infrared excess

We report the discovery of a new gravitationally lensed quasar, SDSS J131339.98+515128.3, at a redshift of 1.875 with an image separation of 1.24". The lensing galaxy is clearly detected in visible-light follow-up observations. We also identify three absorption-line doublets in the spectra of the lensed quasar images, from which we measure the lens redshift to be 0.194. Like several other known lenses, the lensed quasar images have different continuum slopes. This difference is probably the result of reddening and microlensing in the lensing galaxy. The lensed quasar was selected by correlating Sloan Digital Sky Survey (SDSS) spectroscopic quasars with Two Micron All Sky Survey (2MASS) sources and choosing quasars that show near-infrared (IR) excess. The near-IR excess can originate, for example, from the contribution of the lensing galaxy at near-IR wavelengths. We show that the near-IR excess technique is indeed an efficient method to identify lensed systems from a large sample of quasars.Comment: Accepted to MNRAS, 8 pages, 7 figure

SAFT-γ force field for the simulation of molecular fluids: 8. hetero-group coarse-grained models of perfluoroalkylalkanes assessed with new vapour-liquid interfacial tension data

The air-liquid interfacial behaviour of linear perfluoroalkylalkanes (PFAAs) is reported through a combined experimental and computer simulation study. The surface tensions of seven liquid PFAAs (perfluorobutylethane, F4H2; perfluorobutylpentane, F4H5; perfluorobutylhexane, F4H6, perfluorobutyloctane, F4H8; perfluorohexylethane, F6H2; perfluorohexylhexane, F6H6; and perfluorohexyloctane, F6H8) are experimentally determined over a wide temperature range (276 to 350 K). The corresponding surface thermodynamic properties and the critical temperatures of the studied compounds are estimated from the temperature dependence of the surface tension. Experimental density and vapour pressure data are employed to parameterize a generic heteronuclear coarse-grained intermolecular potential of the SAFT- γ family for PFAAs. The resulting force field is used in direct molecular dynamics simulations to predict with quantitative agreement the experimental tensions and to explore the conformations of the molecules in the interfacial region revealing a preferential alignment of the PFAA molecules towards the interface and an enrichment of the perfluoro-groups at the outer interface region

Communication and equilibrium in discontinuous games of incomplete information

This paper offers a new approach to the study of economic problems usually modeled as games of incomplete information with discontinuous payoffs. Typically, the discontinuities arise from indeterminacies (ties) in the underlying problem. The point of view taken here is that the tie-breaking rules that resolve these indeterminacies should be viewed as part of the solution rather than part of the description of the model. A solution is therefore a tie-breaking rule together with strategies satisfying the usual best-response criterion. When information is incomplete, solutions need not exist; that is, there may be no tie-breaking rule that is compatible with the existence of strategy profiles satisfying the usual best-response criteria. It is shown that the introduction of incentive compatible communication (cheap talk) restores existence

Sequence elements controlling expression of Barley stripe mosaic virus subgenomic RNAs in vivo.

Barley stripe mosaic virus (BSMV) contains three positive-sense, single-stranded genomic RNAs, designated alpha, beta, and gamma, that encode seven major proteins and one minor translational readthrough protein. Three proteins (alphaa, betaa, and gammaa) are translated directly from the genomic RNAs and the remaining proteins encoded on RNAbeta and RNAgamma are expressed via three subgenomic messenger RNAs (sgRNAs). sgRNAbeta1 directs synthesis of the triple gene block 1 (TGB1) protein. The TGB2 protein, the TGB2' minor translational readthrough protein, and the TGB3 protein are expressed from sgRNAbeta2, which is present in considerably lower abundance than sgRNAbeta1. A third sgRNA, sgRNAgamma, is required for expression of the gammab protein. We have used deletion analyses and site-specific mutations to define the boundaries of promoter regions that are critical for expression of the BSMV sgRNAs in infected protoplasts. The results reveal that the sgRNAbeta1 promoter encompasses positions -29 to -2 relative to its transcription start site and is adjacent to a cis-acting element required for RNAbeta replication that maps from -107 to -74 relative to the sgRNAbeta1 start site. The core sgRNAbeta2 promoter includes residues -32 to -17 relative to the sgRNAbeta2 transcriptional start site, although maximal activity requires an upstream hexanucleotide sequence residing from positions -64 to -59. The sgRNAgamma promoter maps from -21 to +2 relative to its transcription start site and therefore partially overlaps the gammaa gene. The sgRNAbeta1, beta2, and gamma promoters also differ substantially in sequence, but have similarities to the putative homologous promoters of other Hordeiviruses. These differences are postulated to affect competition for the viral polymerase, coordination of the temporal expression and abundance of the TGB proteins, and constitutive expression of the gammab protein

Experimentally Constrained Molecular Relaxation: The Case of Glassy GeSe2

An ideal atomistic model of a disordered material should contradict no experiments,and should also be consistent with accurate force fields (either {\it ab initio}or empirical). We make significant progress toward jointly satisfying {\it both} of these criteria using a hybrid reverse Monte Carlo approach in conjunction with approximate first principles molecular dynamics. We illustrate the method by studying the complex binary glassy material g-GeSe$_2$. By constraining the model to agree with partial structure factors and {\it ab initio} simulation, we obtain a 647-atom model in close agreement with experiment, including the first sharp diffraction peak in the static structure factor. We compute the electronic state densities and compare to photoelectron spectroscopies. The approach is general and flexible.Comment: 6 pages, 4 figure

Strongly coupled plasma with electric and magnetic charges

A number of theoretical and lattice results lead us to believe that Quark-Gluon Plasma not too far from $T_c$ contains not only electrically charged quasiparticles -- quarks and gluons -- but magnetically charged ones -- monopoles and dyons -- as well. Although binary systems like charge-monopole and charge-dyon were considered in details before in both classical and quantum settings, it is the first study of coexisting electric and magnetic particles in many-body context. We perform Molecular Dynamics study of strongly coupled plasmas with $\sim 1000$ particles and different fraction of magnetic charges. Correlation functions and Kubo formulae lead to such transport properties as diffusion constant, shear viscosity and electric conductivity: we compare the first two with empirical data from RHIC experiments as well as results from AdS/CFT correspondence. We also study a number of collective excitations in these systems.Comment: 2nd version, 22 pages, 32 figures: two important new figures have been included to compare our results with RHIC experiments and AdS/CFT results; a few new references and comments are added as wel

Theory of elastic interaction between colloidal particles in the nematic cell in the presence of the external electric or magnetic field

The Green function method developed in Ref.[S. B. Chernyshuk and B. I. Lev, Phys. Rev. E \textbf{81}, 041707 (2010)] is used to describe elastic interactions between axially symmetric colloidal particles in the nematic cell in the presence of the external electric or magnetic field. General formulas for dipole-dipole, dipole-quadrupole and quadrupole-quadrupole interactions in the homeotropic and planar nematic cells with parallel and perpendicular field orientations are obtained. A set of new results has been predicted: 1) \textit{Deconfinement effect} for dipole particles in the homeotropic nematic cell with negative dielectric anisotropy $\Delta\epsilon<0$ and perpendicular to the cell electric field, when electric field is approaching it's Frederiks threshold value $E\Rightarrow E_{c}$. This means cancellation of the confinement effect found in Ref. [M.Vilfan et al. Phys.Rev.Lett. {\bf 101}, 237801, (2008)] for dipole particles near the Frederiks transition while it remains for quadrupole particles. 2) New effect of \textit{attraction and stabilization} of the particles along the electric field parallel to the cell planes in the homeotropic nematic cell with $\Delta\epsilon<0$ . The minimun distance between two particles depends on the strength of the field and can be ordinary for . 3) Attraction and repulsion zones for all elastic interactions are changed dramatically under the action of the external field.Comment: 15 pages, 17 figure