Scattering by randomly oriented ellipsoids: Application to aerosol and cloud problems

A program was developed for computing the scattering and absorption by arbitrarily oriented and randomly oriented prolate and oblate spheroids. This permits examination of the effect of particle shape for cases ranging from needles through spheres to platelets. Applications of this capability to aerosol and cloud problems are discussed. Initial results suggest that the effect of nonspherical particle shape on transfer of radiation through aerosol layers and cirrus clouds, as required for many climate studies, can be readily accounted for by defining an appropriate effective spherical particle radius

Constraints on Scalar Phantoms

We update the constraints on the minimal model of dark matter, where a stable real scalar field is added to the standard model Lagrangian with a renormalizable coupling to the Higgs field. Once we fix the dark matter abundance, there are only two relevant model parameters, the mass of the scalar field and that of the Higgs boson. The recent data from the CDMS II experiment have excluded a parameter region where the scalar field is light such as less than about 50 GeV. In a large parameter region, the consistency of the model can be tested by the combination of future direct detection experiments and the LHC experiments.Comment: 7 pages, 1 figur

Gamma Ray Bursts: recent results and connections to very high energy Cosmic Rays and Neutrinos

Gamma-ray bursts are the most concentrated explosions in the Universe. They have been detected electromagnetically at energies up to tens of GeV, and it is suspected that they could be active at least up to TeV energies. It is also speculated that they could emit cosmic rays and neutrinos at energies reaching up to the $10^{18}-10^{20}$ eV range. Here we review the recent developments in the photon phenomenology in the light of \swift and \fermi satellite observations, as well as recent IceCube upper limits on their neutrino luminosity. We discuss some of the theoretical models developed to explain these observations and their possible contribution to a very high energy cosmic ray and neutrino background.Comment: 12 pages, 7 figures. Text of a plenary lecture at the PASCOS 12 conference, Merida, Yucatan, Mexico, June 2012; to appear in J.Phys. (Conf. Series

Stringy effect of the holographic correspondence for Dp-brane backgrounds

Based on the holographic conjecture for superstrings on Dp-brane backgrounds and the dual (p+1)-dimensional gauge theory ($0\le p\le 4$) given in hep-th/0308024 and hep-th/0405203, we continue the study of superstring amplitudes including string higher modes ($n\ne 0$). We give a prediction to the two-point functions of operators with large R-charge J. The effect of stringy modes do not appear as the form of anomalous dimensions except for p=3. Instead, it gives non-trivial correction to the two-point functions for supergravity modes. For p=4, the scalar two-point functions for any n behave like free fields of the effective dimension d_{eff}=6 in the infra-red limit.Comment: 23 pages, typos correcte

Quantum theory as a relevant framework for the statement of probabilistic and many-valued logic

Based on ideas of quantum theory of open systems we propose the consistent approach to the formulation of logic of plausible propositions. To this end we associate with every plausible proposition diagonal matrix of its likelihood and examine it as density matrix of relevant quantum system. We are showing that all logical connectives between plausible propositions can be represented as special positive valued transformations of these matrices. We demonstrate also the above transformations can be realized in relevant composite quantum systems by quantum engineering methods. The approach proposed allows one not only to reproduce and generalize results of well-known logical systems (Boolean, Lukasiewicz and so on) but also to classify and analyze from unified point of view various actual problems in psychophysics and social sciences.Comment: 7 page

A Cooper pair light emitting diode

We demonstrate Cooper-pair's drastic enhancement effect on band-to-band radiative recombination in a semiconductor. Electron Cooper pairs injected from a superconducting electrode into an active layer by the proximity effect recombine with holes injected from a p-type electrode and dramatically accelerate the photon generation rates of a light emitting diode in the optical-fiber communication band. Cooper pairs are the condensation of electrons at a spin-singlet quantum state and this condensation leads to the observed enhancement of the electric-dipole transitions. Our results indicate the possibility to open up new interdisciplinary fields between superconductivity and optoelectronics.Comment: 5 pages (4 figures

Josephson current in s-wave superconductor / Sr_2RuO_4 junctions

The Josephson current between an s-wave and a spin-triplet superconductor Sr$_2$RuO$_4$ (SRO) is studied theoretically. In spin-singlet / spin-triplet superconductor junctions, there is no Josephson current proportional to $\sin \phi$ in the absence of the spin-flip scattering near junction interfaces, where $\phi$ is a phase-difference across junctions. Thus a dominant term of the Josephson current is proportional to $\sin 2\phi$ . The spin-orbit scattering at the interfaces gives rise to the Josephson current proportional to $\cos\phi$, which is a direct consequence of the chiral paring symmetry in SRO

Physical States in Canonically Quantized Supergravity

We discuss the canonical quantization of $N=1$ supergravity in the functional Schrodinger representation. Although the form of the supersymmetry constraints suggests that there are solutions of definite order $n$ in the fermion fields, we show that there are no such states for any finite $n$. For $n=0$, a simple scaling argument definitively excludes the purely bosonic states discussed by D'Eath. For $n>0$, the argument is based on a mode expansion of the gravitino field on the quantization 3-surface. It is thus suggested that physical states in supergravity have infinite Grassmann number. This is confirmed for the free spin-3/2 field, for which we find that states satisfying the gauge constraints contain an infinite product of fermion mode operators.Comment: 36 pages (uses jnl.tex), CTP #227