dS/CFT at uniform energy density and a de Sitter "bluewall"

We describe a class of spacetimes that are asymptotically de Sitter in the Poincare slicing. Assuming that a dS/CFT correspondence exists, we argue that these are gravity duals to a CFT on a circle leading to uniform energy-momentum density, and are equivalent to an analytic continuation of the Euclidean AdS black brane. These are solutions with a complex parameter which then gives a real energy-momentum density. We also discuss a related solution with the parameter continued to a real number, which we refer to as a de Sitter "bluewall". This spacetime has two asymptotic de Sitter universes and Cauchy horizons cloaking timelike singularities. We argue that the Cauchy horizons give rise to a blue-shift instability.Comment: Latex, 13pgs, 2 figs. v2: 14pgs, published version, some rephrasing of language in terms of Euclidean CFT on a circle, more elaborate discussion on blueshif

The suppression of superconductivity in Mn substituted MgCNi3_{3}

We report the effect of doping Mn in the isostructural MgCNi$_{3-x}$Mn$_{x}$ (x = 0-0.05) compounds. Magnetic susceptibility, resistivity, magneto-resistance, and specific heat studies show evidence of localized moments and Kondo effect in samples with x$\neq$0. The rapid suppression of superconductivity ($\sim$ -21K/at.% Mn) in these compounds is a consequence of pair breaking effects due to moment formation on Mn.Comment: 9 figures, Accepted for publication in Physical Review B, Added reference

Thermal field theory derivation of the source term induced by a fast parton from the quark energy-momentum tensor

I derive the distribution of energy and momentum transmitted from a fast parton to a medium of thermalized quarks, or the source term, in perturbative thermal field theory directly from the quark energy-momentum tensor. The fast parton is coupled to the medium by adding an interaction term to the Lagrangian. The thermal expectation value of the energy-momentum tensor source term is then evaluated using standard Feynman rules at finite temperature. It is found that local excitations, which are important for exciting an observable Mach cone structure, fall sharply as a function of the energy of the fast parton. This may have implications for the trigger $p_T$ dependence of measurements of azimuthal dihadron particle correlations in heavy-ion collisions. In particular, a conical emission pattern would be less likely to be observed for increasing trigger $p_T$. I show that the results presented in this paper can be generalized to more realistic modeling of fast parton propagation, such as through a time dependent interaction term, in future studies.Comment: Version as accepted by Physical Review D. New version has several clarifications and added references. 5 pages, 3 figure

New Formulas and Predictions for Running Fermion Masses at Higher Scales in SM, 2HDM, and MSSM

Including contributions of scale-dependent vacuum expectation values, we derive new analytic formulas and obtain substantially different numerical predictions for the running masses of quarks and charged-leptons at higher scales in the SM, 2HDM and MSSM. These formulas exhibit significantly different behaviours with respect to their dependence on gauge and Yukawa couplings than those derived earlier. At one-loop level the masses of the first two generations are found to be independent of Yukawa couplings of the third generation in all the three effective theories in the small mixing limit. Analytic formulas are also obtained for running $\tan\beta(\mu)$ in 2HDM and MSSM. Other numerical analyses include study of the third generation masses at high scales as functions of low-energy values of $\tan\beta$ and SUSY scale $M_S=M_Z-10^4$ GeV.Comment: 42 pages RevTeX, including 16 figures. Typos corrected and one reference adde

Efficiency of Indian commercial banks during the reform period

This article contributes to the banking efficiency literature by measuring technical efficiency of banks in four different ownership groups in India during the reform period, 1992–1999. It employs the stochastic frontier function methodology for panel data. The results indicate that the efficiency of raising interest margin is time invariant while the efficiencies of raising other outputs-non-interest income, investments and credits are time varying. The state bank group and foreign banks are more efficient than their counterparts. The reform period witnessed a relatively high efficiency for augmenting investments, which is consistent with economic growth objective of the reform measures. However, there are still larger gaps between the actual and potential performances of banks.

Silicon carbide semiconductor device fabrication and characterization

A number of basic building blocks i.e., rectifying and ohmic contacts, implanted junctions, MOS capacitors, pnpn diodes and devices, such as, MESFETs on both alpha and beta SiC films were fabricated and characterized. Gold forms a rectifying contact on beta SiC. Since Au contacts degrade at high temperatures, these are not considered to be suitable for high temperature device applications. However, it was possible to utilize Au contact diodes for electrically characterizing SiC films. Preliminary work indicates that sputtered Pt or Pt/Si contacts on beta SiC films are someways superior to Au contacts. Sputtered Pt layers on alpha SiC films form excellent rectifying contacts, whereas Ni layers following anneal at approximately 1050 C provide an ohmic contact. It has demonstrated that ion implantation of Al in substrates held at 550 C can be successfully employed for the fabrication of rectifying junction diodes. Feasibility of fabricating pnpn diodes and platinum gated MESFETs on alpha SiC films was also demonstrated

Role of shocked accretion flows in regulating the QPO of galactic black hole candidates

Using a generalized non-spherical, multi-transonic accretion flow model, we analytically calculate the normalized QPO frequency ${\bar {\bf {\nu}}}_{qpo}$ of galactic black hole candidates in terms of dynamical flow variables and self-consistently study the dependence of ${\bar {\bf {\nu}}}_{qpo}$ on such variables. Our results are in fairly close agreement with the observed QPO frequencies of GRS 1915+105. We find that ${\bar {\bf {\nu}}}_{qpo}$ is quite sensitive to various parameters describing the black hole accretion flow containing dissipative and non-dissipative shock waves. Thus the QPO phenomena is, {\it indeed}, regulated by `shocked' black hole accretion, and, for the first time, we establish a definitive connection between the QPO frequency and the properties of advective BH accretion flows. This information may provide the explanation of some important observations of galactic micro quasars.Comment: Final version accepted for publication in the Astrophysical Journal Letters (ApJL). A considerable part of the paper is almost completely re-written, though the results and the final conclussions are the same. One can now ignore the previous version. 8 pages with four black and white figures. For high resolution Fig. 3, please mail the author <[email protected]