Greybody factor for the BTZ black hole and a 5D black hole

We study the 5D black holes in the type IIB superstring theory compactified on $S^1 \times T^4$. Far from horizon, we have flat space-time. Near horizon, we have $AdS_3(BTZ black hole) \times S^3 \times T^4$. We calculate the greybody factor of a minimally coupled scalar by replacing the original geometry($M_5 \times S^1 \times T^4$) by $AdS_3 \times S^3 \times T^4$. In the low-energy scattering, it turns out that the result agrees with the greybody factor of the 5D black hole (or D1 + D5 branes)in the dilute gas approximation. This confirms that the $AdS$-theory($AdS_3 \times S^3 \times T^4$) contains the essential information about the bulk 5D black holes.Comment: some discussions are added, 15 Pages, No figure, RevTe

Acoustic properties of turbofan inlets

The acoustic field within a duct containing a nonuniform steady flow was predicted. This analysis used the finite element method to calculate the velocity potential within the duct

Fluctuating initial conditions in heavy-ion collisions from the Glauber approach

In the framework of the Glauber approach we analyze the shape parameters of the early-formed system and their event-by-event fluctuations. We test a variety of models: the conventional wounded nucleon model, a model admixing binary collisions to the wounded nucleons, a model with hot spots, as well as the hot-spot model where the deposition of energy occurs with a superimposed probability distribution. We look in detail at the so-called participant multipole moments, obtained by an averaging procedure where in each event the system is translated to its center of mass and aligned with the major principal axis of the ellipse of inertia. Quantitative comparisons indicate substantial relative effects for eccentricity in variants of Glauber models. On the other hand, the dependence of the scaled standard deviation of the participant eccentricity on the chosen model is weak. For all models the values range from about 0.5 for the central collisions to about 0.3-0.4 for peripheral collisions, both for the gold-gold and copper-copper collisions. They are dominated by statistics and change only by 10-15% from model to model. We provide an approximate analytic expansion for the multipole moments and their fluctuations given in terms of the fixed-axes moments. For central collisions and in the absence of correlations it gives the simple formula for the scaled standard deviation of the participant eccentricity: sqrt(4/pi-1). Similarly, we obtain expansions for the radial profiles of the multipole distributions. We investigate the relevance of the shape-fluctuation effects for jet quenching and find them important only for very central events. Finally, we argue how smooth hydro leads to the known result v_4 ~ v_2^2, and further to the prediction Delta v_4/v_4 = 2 Delta v_2/v_2.Comment: 20 pages, 15 figures, additions include comparison to the CGC result

Delta Excitations in Neutrino-Nucleus Scattering

We derive the contribution of $\Delta$-h excitations to quasielastic charged-current neutrino-nucleus scattering in the framework of relativistic mean-field theory. We discuss the effect of $\Delta$ production on the determination of the axial mass $M_A$ in neutrino scattering experiments.Comment: 14 pages, revtex, 3 postscript figures (available upon request

Diagnosing Energy Loss: PHENIX Results on High-pT Hadron Spectra

Measurements of inclusive spectra of hadrons at large transverse momentum over a broad range of energy in different collision systems have been performed with the PHENIX experiment at RHIC. The data allow to study the energy and system size dependence of the suppression observed in RAA of high-pT hadrons at sqrt(s_NN)= 200 GeV. Due to the large energy range from sqrt(s_NN)= 22 GeV to 200 GeV, the results can be compared to results from CERN SPS at a similar energy. The large Au+Au dataset from the 2004 run of RHIC also allows to constrain theoretical models that describe the hot and dense matter produced in such collisions. Investigation of particle ratios such as eta/pi0 helps understanding the mechanisms of energy loss.Comment: 4 pages, 6 figures. To appear in the proceedings of the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter 2006), Shanghai, China, November 14-20, 200

Strong Correlations in Actinide Redox Reactions

Reduction-oxidation (redox) reactions of the redox couples An(VI)/An(V), An(V)/An(IV), and An(IV)/An(III), where An is an element in the family of early actinides (U, Np, and Pu), as well as Am(VI)/Am(V) and Am(V)/Am(III), are modeled by combining density functional theory with a generalized Anderson impurity model that accounts for the strong correlations between the 5f electrons. Diagonalization of the Anderson impurity model yields improved estimates for the redox potentials and the propensity of the actinide complexes to disproportionate.Comment: 17 pages, 10 figure, 3 tables. Corrections and clarifications; this version has been accepted for publication in The Journal of Chemical Physic

Opportunities for optics in integrated circuits applications

Optics potentially addresses two key problems in electronic chips and systems: interconnects and timing. Short optical pulses (e.g., picoseconds or shorter) offer particularly precise timing. Results are shown for optical and electrical four-phase clocking, with <1 ps rms jitter for the optical case

Nuclear medium modifications of the NN interaction via quasielastic (p⃗,p⃗′\vec p,\vec p ') and (p⃗,n⃗\vec{p},\vec{n}) scattering

Within the relativistic PWIA, spin observables have been recalculated for quasielastic ($\vec p,\vec p '$) and ($\vec p,\vec n$) reactions on a $^{40}$Ca target. The incident proton energy ranges from 135 to 300 MeV while the transferred momentum is kept fixed at 1.97 fm^{-1}. In the present calculations, new Horowitz-Love--Franey relativistic NN amplitudes have been generated in order to yield improved and more quantitative spin observable values than before. The sensitivities of the various spin observables to the NN interaction parameters, such as (1) the presence of the surrounding nuclear medium, (2) a pseudoscalar versus a pseudovector interaction term, and (3) exchange effects, point to spin observables which should preferably be measured at certain laboratory proton energies, in order to test current nuclear models. This study also shows that nuclear medium effects become more important at lower proton energies ($\leq$ 200 MeV). A comparison to the limited available data indicates that the relativistic parametrization of the NN scattering amplitudes in terms of only the five Fermi invariants (the SVPAT form) is questionable.Comment: 10 pages, 6 Postscript figures, uses psfig.sty and article.sty, submitted to Phys. Rev.

Neutron Star Structure and the Neutron Radius of 208Pb

We study relationships between the neutron-rich skin of a heavy nucleus and the properties of neutron-star crusts. Relativistic effective field theories with a thicker neutron skin in $^{208}$Pb have a larger electron fraction and a lower liquid-to-solid transition density for neutron-rich matter. These properties are determined by the density dependence of the symmetry energy which we vary by adding nonlinear couplings between isoscalar and isovector mesons. An accurate measurement of the neutron radius in $^{208}$Pb---via parity violating electron scattering---may have important implications for the structure of neutron stars.Comment: 5 pages 3 figures, added additional evidence of model independence, Phys. Rev. Letters in pres