arXiv papers from October 2004

A. K. Kwasniewski

Umbral extensions of the stirling numbers of the second kind are considered and the resulting dobinski-like various formulas including new ones are presented. These extensions naturally encompass the two well known q-extensions. The further consecutive umbral extensions q-stirling numbers are therefore realized here in a two-fold way. The fact that the umbra

Ravi Montenegro

We consider the problem of lower bounding a generalized Minkowski measure of subsets of a convex body with a log-concave probability measure, conditioned on the set size. A bound is given in terms of diameter and set size, which is sharp for all set sizes, dimensions, and norms. In the case of uniform density a stronger theorem is shown which is also sharp.

V. Kreiman, V. Lakshmibai, P. Magyar, J. Weyman

We give an elementary and easily computable basis for the Demazure modules in the basic representation of the affine Lie algebra sl(n)-hat (and the loop group SL(n)-hat). A novel feature is that we define our basis ``bottom-up'' by raising each extremal weight vector, rather than ``top-down'' by lowering the highest weight vector. Our basis arises naturally

Sungbok Hong, Darryl McCullough, J. Hyam Rubinstein

The original Smale Conjecture asserted that the inclusion of the group O(4) of isometries of the round 3-sphere S into the full diffeomorphism group Diff(S) is a homotopy equivalence. The (Generalized) Smale Conjecture asserts that the inclusion of Isom(M) into Diff(M) is a homotopy equivalence whenever M is an elliptic 3-manifold, that is, a closed Riemanni

S. W. Ham, S. K. OH, D. Son

By assuming the existence of the sequential fourth generation to the minimal supersymmetric standard model (MSSM), we study the possibility of a strongly first-order electroweak phase transition. We find that there is a parameter region of the MSSM where the electroweak phase transition is strongly first order. In that parameter region, the mass of the light

Jonathan L. Rosner

The importance of measuring the non-$D \bar D$ decays of the $\psi'' = \psi(3770)$ resonance is discussed. These decays can shed light on a possible discrepancy between the total and $D \bar D$ cross sections at the $\psi''$, and on a proposed mechanism for enhancement of penguin amplitudes in $B$ meson decays through charm--anticharm annihilation. Measureme

Jun-ichi Nakashima

The author reports a result of an interferometric observation of the semiragular pulsating star with an unusual narrow molecular line profile, X Her, in the CO J=1-0 line with the Berkeley-Illinois-Maryland array. In the CO spectrum, a double-component profile (including narrow and broad components) is seen as reported by previous observations. The narrow co

H. Yuksel

Emergence of neutrino physics is fueled by the recent growth in quality and quantity of experimental data, yet, there are still open questions. How much can the determination of mixing parameters be improved? Can we improve bounds on theta_13 before experiments designed specifically for this parameter start? How well can we determine or limit sterile fractio

Ciprian Manolescu

Seidel and Smith have constructed an invariant of links as the Floer cohomology for two Lagrangians inside a complex affine variety Y. This variety is the intersection of a semisimple orbit with a transverse slice at a nilpotent in the Lie algebra $sl_{2m}.$ We exhibit bijections between a set of generators for the Seidel-Smith cochain complex, the generator

Peter Kuchment

The paper deals with some spectral properties of (mostly infinite) quantum and combinatorial graphs. Quantum graphs have been intensively studied lately due to their numerous applications to mesoscopic physics, nanotechnology, optics, and other areas. A Schnol type theorem is proven that allows one to detect that a point belongs to the spectrum when a genera

Dave Auckly, Martin Speight

The fundamental group and rational cohomology of the configuration spaces of the Skyrme and Faddeev-Hopf models are computed. Physical space is taken to be a compact oriented 3-manifold, either with or without a marked point representing an end at infinity. For the Skyrme model, the codomain is any Lie group, while for the Faddeev-Hopf model it is $S^2$. It

Kaihua Cai

We prove $t^{- \frac 14}-$decay for the solutions of the 1-dim Schrodinger equation with a one-gap periodic potential as $t \to +\infty $. Generically, one has $t^{- \frac 13}$-decay and this decay is optimal. Our approach is to analyze the stationary phase in the Schr\"odinger evolution as an integral operator.

John M. Carpenter, Sebastian Wolf, Katharina Schreyer, Ralf Launhardt

We present submillimeter (CSO 350um) and millimeter (SEST 1.2 mm, OVRO 3 mm) photometry for 125 solar-type stars from the FEPS Spitzer Legacy program that have masses between ~0.5 and 2.0 Msun and ages from 3 Myr to 3 Gyr. Continuum emission was detected toward four stars with a signal to noise ratio >= 3$: the classical T Tauri stars RX J1842.9-3532, RX J18

Mei-Lin Yau

We give a proof of, for the case of contact structures defined by global contact 1-forms, a Theorem stated by Eliashberg that for any overtwisted contact structure on a closed 3-manifold, its contact homology is 0. A different proof is also outlined in the appendix by Yakov Eliashberg.

Igor V. Roshchin, O. Petracic, R. Morales, Zhi-Pan Li

When a ferromagnet is in proximity with an antiferromagnet, lateral length scales such as the respective magnetic domain sizes drastically affect the exchange bias. Bilayers of FeF2 and either Ni, Co or Fe are studied using SQUID and spatially resolved MOKE. When the antiferromagnetic domains are larger than or comparable to the ferromagnetic domains, a loca

V. V. Begun, M. I. Gorenstein, O. S. Zozulya

The particle number and energy fluctuations in the system of charged particles are studied in the canonical ensemble for non-zero net values of the conserved charge. In the thermodynamic limit the fluctuations in the canonical ensemble are different from the fluctuations in the grand canonical one. The system with several species of particles is considered.

Sergei Bashinsky

When the perturbations forming the acoustic peaks of the cosmic microwave background (CMB) reentered the horizon and interacted gravitationally with all the matter, neutrinos presumably comprised 41% of the universe energy. CMB experiments have reached a capacity to probe this background of relic neutrinos. I review the neutrino impact on the CMB at the onse

Thorsten Theobald

We study some basic algorithmic problems concerning the intersection of tropical hypersurfaces in general dimension: deciding whether this intersection is nonempty, whether it is a tropical variety, and whether it is connected, as well as counting the number of connected components. We characterize the borderline between tractable and hard computations by pr

J. Fleckinger, E. M. Harrell, F. de Thélin

It is shown that the fundamental eigenvalue ratio \lambda_2 / \lambda_1 of the p-Laplacian is bounded by a quantity depending only on the dimension N and p.

G. Vernizzi, H. Orland, A. Zee

We enumerate the number of RNA contact structures according to their genus, i.e. the topological character of their pseudoknots. By using a recently proposed matrix model formulation for the RNA folding problem, we obtain exact results for the simple case of an RNA molecule with an infinitely flexible backbone, in which any arbitrary pair of bases is allowed

S. Kuperstein, J. Sonnenschein

We study certain properties of the low energy regime of a theory which resembles four dimensional YM theory in the framework of a non-critical holographic gravity dual. We use for the latter the near extremal $AdS_6$ non-critical SUGRA. We extract the glueball spectra that associates with the fluctuations of the dilaton, one form and the graviton and compare

P. Ramond

The prediction of small neutrino masses through the Seesaw Mechanism and their subsequent measurement suggests that the natural cut-off of the Standard Model is very high indeed. The recent neutrino data must be interpreted as a reflection of physics at very high energy. We examine their implications in terms of ideas of Grand Unification and Supersymmetry,

G. N. Ord, J. A. Gualtieri, R. B. Mann

In the path integral formulation of quantum mechanics, the phase factor Exp[iS(x[t])] is associated with every path x[t]. Summing this factor over all paths yields Feynman's propagator as a sum-over-paths. In the original formulation, the complex phase was a mathematical device invoked to extract wave behaviour in a particle framework. In this paper we show

P. Ramond

The Seesaw mechanism predicted tiny neutrino masses by postulating a new large scale in particle physics, using new theoretical ideas prompted by the Standard Model. It adds credence to a theoretical vista that is a quarter century old, and fits with the most endearing speculations of ultimate unification. By relating the measurement of static neutrino prope

Antony Eagle

Recently a suggestion has been made that standard textbook representations of hypersurfaces of simultaneity for the travelling twin in the twin "paradox" are incorrect. This suggestion is false: the standard textbooks are in agreement with a proper understanding of the relativity of simultaneity.

Nathanaël Berestycki

Turn the set of permutations of $n$ objects into a graph $G_n$ by connecting two permutations that differ by one transposition, and let $\sigma_t$ be the simple random walk on this graph. In a previous paper, Berestycki and Durrett [In Discrete Random Walks (2005) 17--26] showed that the limiting behavior of the distance from the identity at time $cn/2$ has

Knut Smoczyk, Guofang Wang, Y. L. Xin

We show that flatness of the normal bundle is preserved under the mean curvature flow in the Euclidean space and use this to generalize a classical result for hypersurfaces due to Ecker-Huisken in the case of submanifolds with arbitrary codimension.

P. Domin, S. Kovalenko, F. Simkovic, S. V. Semenov

The systematic study of (anti-)neutrino accompanied beta^-beta^-, beta^+beta^+ decays and beta^+/EC, EC/EC electron captures is performed under the assumption of single intermediate nuclear state dominance. The corresponding half-lives are evaluated both for transitions to the ground state as well as to the 0^+ and 2^+ excited states of final nucleus. It is

Hoi-Kwong Lo, Xiongfeng Ma, Kai Chen

There has been much interest in quantum key distribution. Experimentally, quantum key distribution over 150 km of commercial Telecom fibers has been successfully performed. The crucial issue in quantum key distribution is its security. Unfortunately, all recent experiments are, in principle, insecure due to real-life imperfections. Here, we propose a method

Eran Nevo

Gluck (1975) has proven that triangulated 2-spheres are generically 3-rigid. Equivalently, planar graphs are generically 3-stress free. We show that linklessly embeddable graphs are generically 4-stress free. Both of these results are corollaries of the following theorem: every K_{r+2}-minor free graph is generically r-stress free for 0<r<5. (This assertion

Sergio Albeverio, Carlo Marinelli

The problem of reconstructing the drift of a diffusion in $\erre^d$, $d\geq 2$, from the transition probability density observed outside a domain is considered. The solution of this problem also solves a new inverse problem for a class of parabolic partial differential equations. This work considerably extends \cite{jsp} in terms of generality, both concerni

Ewa Krot

The explicite formulas for m\"{o}biusien function and some other important elements of the incidence algebra are delivered. For that to do one uses kwa\'sniewski's construction of his fibonacci cobweb poset in the plane grid coordinate system.

Laura Lising, Andrew Elby

We discuss a case study of the influence of epistemology on learning for a student in an introductory college physics course. An analysis of videotaped class work, written work, and interviews indicates that many of the student's difficulties were epistemological in nature. Our primary goal is to show instructors and curriculum developers that a student's ep

P. Lesaffre, Ph. Podsiadlowski, C. A. Tout

One possible fate of an accreting white dwarf is explosion in a type Ia supernova. However, the route to the thermonuclear runaway has always been uncertain owing to the lack of a convective model consistent with the Urca process. We derive a formalism for convective motions involving two radial flows. This formalism provides a framework for convective model

M. Beneke, N. Kauer, A. Signer, G. Zanderighi

We illustrate the use of effective theory techniques to describe processes involving unstable particles close to resonance. First, we present the main ideas in the context of a scalar resonance in an Abelian gauge-Yukawa model. We then outline the necessary modifications to describe W-pair production close to threshold in electron-positron collisions.

P. Lesaffre, Ph. Podsiadlowski, C. A. Tout

We derive a new formalism for convective motions involving two radial flows. This formalism provides a framework for convective models that guarantees consistency for the chemistry and the energy budget in the flows, allows time-dependence and accounts for the interaction of the convective motions with the global contraction or expansion of the star. In the

Piotr T. Chrusciel

We review selected recent results concerning the global structure of solutions of the vacuum Einstein equations. The topics covered include quasi-local mass, strong cosmic censorship, non-linear stability, new constructions of solutions of the constraint equations, improved understanding of asymptotic properties of the solutions, existence of solutions with

A. A. Kokin

It is considered the indirect inter-qubit coupling in 1D chain of atoms with nuclear spins 1/2, which plays role of qubits in the quantum register. This chain of the atoms is placed by regular way in easy-axis 3D antiferromagnetic thin plate substrate, which is cleaned from the other nuclear spin containing isotopes. It is shown that the range of indirect in

Y. Fuseya, Y. Suzumura

The anisotropic superconductivity and the density wave have been investigated by applying the Kadanoff-Wilson renormalization group technique to the quasi-one-dimensional system with finite-range interactions. It is found that a temperature (T) dependence of response functions is proportional to exp(1/T) in a wide region of temperature even within the one-lo

Hiroshi Oda, Toshio Oshima

Let g be a complex reductive Lie algebra and U(g) the universal enveloping algebra of g. Associated to a faithful irreducible finite dimensional representation of g, a square matrix F with entries in U(g) naturally arises and if we consider the entries of F are elements in End(M) of a given U(g)-module M, the minimal polynomial of F is defined as the usual o

Zhen Ye

This paper considers acoustic scattering by and propagation through line and plane arrays of air-bubbles in liquid media. The self-consistent method is used to derive the effective scattering function of a single bubble embedded in the arrays, incorporating all multiple scattering processes. For the line case, an exact result is derived. In the plane array s

Alfred J. van der Poorten

We generalise remarks of Euler and of Perron by explaining how to detail all quadratic irrational integers for which the symmetric part of the period of their continued fraction expansion commences with prescribed partial quotients. The function field case is particularly striking.

D. J. Christian, D. L. Pollacco, W. I. Clarkson, A. Collier Cameron

We present the current status of the SuperWASP project, a Wide Angle Search for Planets. SuperWASP consists of up to 8 individual cameras using ultra-wide field lenses backed by high-quality passively cooled CCDs. Each camera covers 7.8 x 7.8 sq degrees of sky, for nearly 500 sq degrees of sky coverage. SuperWASP I, located in LaPalma, is currently operation

R. X. Xu, A. Z. Zhou

A quake model of bare strange stars for normal pulsar glitches is summarized. Three mechanisms being responsible for developing elastic stress energy are presented. It is suggested that other kinds of glitches (e.g, the frequency glitch in KS 1947+300 and in AXP/SGRs) could represent the bulk-strain-induced quakes. The apparent field increase of normal pulsa

Bruce W. Carney, Jae-Woo Lee, Benjamin Dodson

We present deep JHK photometry of the old and metal-rich open cluster NGC 6791. The photometry reaches below the main sequence turn-off to K = 16.5 mag. We combine our photometry with that from Stetson, Bruntt, & Grundahl (2003) to provide color-magnitude diagrams showing K vs. J-K, K vs. V-K, and V vs. V-K. We study the slope of the red giant branch in the

Kai Wang, Nilanjana Banerjee, Adam Margolin, Ilya Nemenman

Cellular phenotypes are determined by the dynamical activity of networks of co-regulated genes. Elucidating such networks is crucial for the understanding of normal cell physiology as well as for the dissection of complex pathologic phenotypes. Existing methods for such "reverse engineering" of genetic networks from microarray expression data have been succe

Xin He Meng, Peng Wang

In this paper by deriving the Modified Friedmann equation in the Palatini formulation of $R^2$ gravity, first we discuss the problem of whether in Palatini formulation an additional $R^2$ term in Einstein's General Relativity action can drive an inflation. We show that the Palatini formulation of $R^2$ gravity cannot lead to the gravity-driven inflation as i

G. Pancheri, Y. Srivastava, N. Staffolani

A sum rule is derived for elastic scattering of hadrons at high energies which is in good agreement with experimental data on $p\bar{p}$ available upto the maximum energy $\sqrt{s} = 2 TeV$. Physically, our sum rule reflects the way unitarity correlates and limits how large the elastic amplitude can be as a function of energy to how fast it decreases as a fu

F. Kheirandish, M. Amooshahi

By modeling a dielectric medium with two independent reservoirs, i.e., electric and magnetic reservoirs, the electromagnetic field is quantized in a linear dielectric medium consistently. A Hamiltonian is proposed from which using the Heisenberg equations, not only the Maxwell equations but also the structural equations can be obtained. Using the Laplace tra

G. Pancheri, R. Godbole, A. Grau, Y. N. Srivastava

The physics underlying the fall and eventual rise in various total cross-sections at high energies has been investigated over a decade using a model based on the Bloch-Nordsieck resummation in QCD. Here a brief review of our latest results is presented and comparison made with experimental data on $pp$, $\gamma proton$ and $\gamma \gamma$ total cross-section

Jörn Dunkel, Peter Hänggi

We construct a theory for the 1+1-dimensional Brownian motion in a viscous medium, which is (i) consistent with Einstein's theory of special relativity, and (ii) reduces to the standard Brownian motion in the Newtonian limit case. In the first part of this work the classical Langevin equations of motion, governing the nonrelativistic dynamics of a free Brown

D. B. Henley, I. R. Stevens, J. M. Pittard

We present a new analysis of an archived Chandra HETGS X-ray spectrum of the WR+O colliding wind binary Gamma Velorum. The spectrum is dominated by emission lines from astrophysically abundant elements: Ne, Mg, Si, S and Fe. From a combination of broad-band spectral analysis and an analysis of line flux ratios we infer a wide range of temperatures in the X-r

Horacio E. Camblong, Carlos R. Ordonez

The thermodynamics of black holes is shown to be directly induced by their near-horizon conformal invariance. This behavior is exhibited using a scalar field as a probe of the black hole gravitational background, for a general class of metrics in D spacetime dimensions (with $D \geq 4$). The ensuing analysis is based on conformal quantum mechanics, within a

Stephen Semmes

These notes, associated with a topics course, are concerned with Hausdorff measures and Lipschitz functions on metric spaces.

J. E. Daily, R. Gommers, E. A. Cummings, D. S. Durfee

We report an optical dipole trap for calcium. The trap is created by focusing a 488 nm argon-ion laser beam into a calcium magneto-optical trap. The argon-ion laser photo-ionizes atoms in the trap because of a near-resonance with the 4s4f 1F3 level. By measuring the dipole trap decay rate as a function of argon-ion laser intensity, we determine the 1F3 photo

Steven D. Bass

This article reviews our present understanding of the QCD spin structure of the proton. We first outline the proton spin puzzle and its possible resolution in QCD. We then review the present and next generation of experiments to resolve the proton's spin-flavour structure, explaining the theoretical issues involved, the present status of experimental investi

Alvaro Gonzalez, Javier B. Gomez, Amalio F. Pacheco

The occurrence of the September 28, 2004 Mw=6.0 mainshock at Parkfield, California, has significantly increased the mean and aperiodicity of the series of time intervals between mainshocks in this segment of the San Andreas fault. We use five different statistical distributions as renewal models to fit this new series and to estimate the time-dependent proba

Tamas Varga

Permutation actions of simple currents on the primaries of a Rational Conformal Field Theory are considered in the framework of admissible weighted permutation actions. The solution of admissibility conditions is presented for cyclic quadratic groups: an irreducible WPA corresponds to each subgroup of the quadratic group. As a consequence, the primaries of a

L. A. Openov, A. V. Tsukanov

Quantum operations with a charge solid-state qubit whose logical states are formed by two spatially separated localized states of an electron in the double-dot structure are studied theoretically. We show that it is possible to perform various one-qubit rotations making use of the microwave pulses tuned to the resonances between the localized states and the

Yaron Bromberg, M. C. Cross, Ron Lifshitz

We study the response of a large array of coupled nonlinear oscillators to parametric excitation, motivated by the growing interest in the nonlinear dynamics of microelectromechanical and nanoelectromechanical systems (MEMS and NEMS). Using a multiscale analysis, we derive an amplitude equation that captures the slow dynamics of the coupled oscillators just

M. J. Seaton

All monochromatic opacity data from the Opacity Project (OP), together with all codes required for the calculation of mean opacities and radiative accelerations for any required chemical mixture, temperature and mass-density, are being put on a 700 Mb CD which will be made generally available. The present paper gives a concise summary of the contents of the

Masoud Khalkhali, Bahram Rangipour

We construct cup products of two different kinds for Hopf-cyclic cohomology. When the Hopf algebra reduces to the ground field our first cup product reduces to Connes' cup product in ordinary cyclic cohomology. The second cup product generalizes Connes-Moscovici's characteristic map for actions of Hopf algebras on algebras.

L. N. Shehata, H. M. Taha

The modified Ginzburg-Landau equations are used to study some fundamental problems for the high temperature superconductors. The derivations of these fundamental equations are summarized and the layered features of the sample were taken into consideration and the relation between the coherence length and the separation distance of the layers. The domain wall

David H. Douglass, B. David Clader, Robert S. Knox

This paper is a continuation of a study by Douglass and Clader. We extend the analysis through December 2003 using the latest updates of the observational temperature and solar irradiance data sets in addition to a new volcano proxy data set. We have re-determined the solar effect on the temperature from satellite measurements of the solar irradiance and the

Colin Benjamin

The order parameter of High-T$_{c}$ superconductors through a series of experiments has been quite conclusively demonstrated to not be of the normal $s-wave$ type. It is either a pure $d_{x^{2}-y^{2}}$-wave type or a mixture of a $d_{x^{2}-y^{2}}-wave$ with a small imaginary $s-wave$ or $d_{xy}-wave$ component. In this work a distinction is brought out among

Xin Liu, Xiong-Jun Liu, Mo-Lin Ge

The dynamics of the domain wall (DW) in a biaxial ferromagnet interacting with a spin-polarized current are described by sine-gordon (SG) equation coupled with Gilbert damping term in this paper. Within our frame-work of this model, we obtain a threshold of the current in the motion of a single DW with the perturbation theory on kink soliton solution to the

Bogdan Damski

It is shown that dynamics of the Landau-Zener model can be accurately described in terms of the Kibble-Zurek theory of the topological defect production in nonequilibrium phase transitions. The simplest quantum model exhibiting the Kibble-Zurek mechanism is presented. A new intuitive description of Landau-Zener dynamics is found.

P. Sancho

Multimode two-particle systems show interference effects in one-particle detections when both particles have common modes. We explore the possibility of extending the usual concepts of distinguishability and visibility to these types of systems. Distinguishability will refer now to the balance between common and different modes of a two-particle system, inst

W. Bietenholz, S. Capitani, T. Chiarappa, N. Christian

We compare the behavior of overlap fermions, which are chirally invariant, and of Wilson twisted mass fermions at full twist in the approach to the chiral limit. Our quenched simulations reveal that with both formulations of lattice fermions pion masses of O(250 MeV) can be reached in practical applications. Our comparison is done at a fixed value of the lat

F. Bentosela, P. Duclos, G. Nenciu, V. Moldoveanu

We study the dynamics of a 1D Bloch electron subjected to a constant electric field. The periodic potential is supposed to be less singular than the $\delta $-like potential (Dirac comb). We give a rigorous proof of Ao's result \cite{Ao} that for a large class of initial conditions (high momentum regime) there is no localization in momentum space. The proof

Jaemo Park, Takao Suyama

We investigate a deformed matrix model of type 0A theory related to supersymmetric Witten's black hole in two-dimensions, generalization of bosonic model suggested by Kazakov et. al. We find a free field realization of the partition function of the matrix model, which includes Ramond-Ramond perturbations in the type 0A theory. In a simple case, the partition

Yu Tian, Han-Ying Guo, Chao-Guang Huang, Zhan Xu

We focus on the dynamical aspects of Newton-Hooke space-time ${\cal NH}_+$ mainly from the viewpoint of geometric contraction of the de Sitter spacetime. We first discuss the Newton-Hooke classical mechanics, especially the continuous medium mechanics, in this framework. Then, we establish a consistent theory of gravity on the Newton-Hooke space-time as a ki

G. Giachetta, L. Mangiarotti, G. Sardanashvily

Covariant (polysymplectic) Hamiltonian field theory is formulated as a particular Lagrangian theory on a polysymplectic phase space that enables one to quantize it in the framework of familiar quantum field theory.

J. A. Belinchón

It is investigated the behaviour of the ``constants'' $G,$ $c$ and $\Lambda $ in the framework of a perfect fluid LRS Bianchi I cosmological model. It has been taken into account the effects of a $c-$variable into the curvature tensor. Two exact cosmological solutions are investigated, arriving to the conclusion that if $q<0$ (deceleration parameter) then $G

Pietro Menotti, Gabriele Vajente

We solve the Riemann-Hilbert problem on the sphere topology for three singularities of finite strength and a fourth one infinitesimal, by determining perturbatively the Poincare' accessory parameters. In this way we compute the semiclassical four point vertex function with three finite charges and a fourth infinitesimal. Some of the results are extended to t

Shuang-Qing Wu

The conformal thermodynamics of rotating charged black holes in general relativity and string theory is proposed by considering the first laws of thermodynamics for a pair of systems made up of the two horizons of a Kerr-Newman or Kerr-Sen black hole. These two systems are constructed by only demanding their ``horizon areas'' to be the sum and difference of

Hsiao-Wen Chen, Robert C. Kennicutt, Michael Rauch

We present a spectroscopic study of six damped Lya absorption (DLA) systems at z<0.65, based on moderate-to-high resolution spectra of the galaxies responsible for the absorbers. Combining known metallicity measurements of the absorbers with known optical properties of the absorbing galaxies, we confirm that the low metal content of the DLA population can ar

Christian Schmidt, Philip B. Allen, Tunna Baruah, Mark Pederson

Density functional theory (DFT) is used to study vibrations, electrical dipole moments, and polarizabilities of NaF clusters. Because of prior experimental and theoretical studies, this is a good model system for tracking the evolution of the properties from diatomic molecule to bulk crystal. The ratio of vibrational to electronic contributions to the polari

Zhen Ye

Here I present an overview of recent studies of the phenomenon of negative refraction and left-handed materials. I will discuss some basic questions pertinent to the problem. It is pointed out that the current claims of negative refraction and left handed materials are not conclusive. To support our consideration, I will start with the fundamental physics.

Jian-Ming Tang, Michael E. Flatte&#39;

We study sharp low-energy resonance peaks in the local density of states (LDOS) induced by Zn impurities or possible Cu vacancies in superconducting Bi_2Sr_2CaCu_2O_{8+delta}. The measured structure of these near-zero-bias resonances is quantitatively reproduced by an extended impurity potential without invoking internal impurity states or sophisticated tunn

Chao-Hsien Kuo, Zhen Ye

In a recent communication, Parimi et al. (Nature 426, 404 (2003)) reported the experimental results on imaging by a flat lens made of photonic crystals. They attributed the observed focusing to the negative refraction expected for the Left-Handed-Materials (LHMs). Here we demonstrate that the experimental observation is irrelevant to the negative refraction

L. C. Popovic

In order to investigate the connection between the X-ray, UV and optical spectral line regions, we selected a sample of AGN which have the strong Fe K-alpha line and analyze the UV and optical spectral lines. Here we present an example of AGN NGC 3516. In this object it seems that geometries of all three emitting regions are similar, i.e. the broad line shap

T. von Hippel, D. E. Winget, W. H. Jefferys, J. G. Scott

We present an update of our on-going effort to improve the precision of white dwarf cosmochronology via careful analyses of white dwarf photometry in open clusters. To improve the precision of white dwarf and main sequence age analysis, we are developing a new interpretative scheme using a Bayesian statistical approach that matches observations to simulated

T. von Hippel, M. Kilic, J. Munn, H. Harris

We describe a new survey for cool white dwarfs that supplements Sloan Digital Sky Survey photometry with USNO proper motions and follow-up spectroscopy. To date we have discovered and spectroscopically confirmed 80 new moderate temperature and cool white dwarfs. We have also found a handful of high-velocity white dwarfs and we expect a sizable fraction of th

Roustam Zalaletdinov

A review on the main results concerning the algebraic and differential properties of the averaging and coordination operators and the properties of the space-time averages of macroscopic gravity is given. The algebraic and differential properties of the covariant space-time averaging procedure by means of using the parallel transportation averaging bivector

S. I. Ipatov, J. C. Mather

We integrated the orbital evolution of 30,000 Jupiter-family comets, 1300 resonant asteroids, and 7000 asteroidal, trans-Neptunian, and cometary dust particles. For initial orbital elements of bodies close to those of Comets 2P, 10P, 44P, and 113P, a few objects got Earth-crossing orbits with semi-major axes $a$$<$2 AU and moved in such orbits for more than

S. I. Ipatov, J. C. Mather

The orbital evolution of Jupiter-family comets (JFCs), resonant asteroids, and asteroidal, trans-Neptunian, and cometary dust particles under the gravitational influence of planets was integrated. For dust particles we also considered radiation pressure, Poynting-Robertson drag, and solar wind drag. The probability of a collision of one former JFC with a ter

L. H. Ford, R. P. Woodard

We express stress tensor correlators using the Schwinger-Keldysh formalism. The absence of off-diagonal counterterms in this formalism ensures that the +- and -+ correlators are free of primitive divergences. We use dimensional regularization in position space to explicitly check this at one loop order for a massless scalar on a flat space background. We use

Benjamin F. Williams, Michael R. Garcia, Albert K. H. Kong, Frank A. Primini

We have obtained snapshot images of an X-ray nova in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The Chandra position of the X-ray nova was R.A.=00:44:06.68 +/- 1.74", Dec.=+41:12:20.0 +/- 2.31". A follow-up HST observation 24 days later revealed a source at R.A.=00:44:06.81, Dec.=+41:12:24.0 that was B=25.

Hugh Nymeyer, Thomas B. Woolf, Angel E. Garcia

We implement the replica exchange molecular dynamics algorithm to study the interactions of a model peptide (WALP-16) with an explicitly represented DPPC membrane bilayer. We observe the spontaneous, unbiased insertion of WALP-16 into the DPPC bilayer and its folding into an a-helix with a trans-bilayer orientation. We observe that the insertion of the pepti

C. Galbiati, A. Pocar, D. Franco, A. Ianni

Several possible background sources determine the detectability of pep and CNO solar neutrinos in organic liquid scintillator detectors. Among such sources, the cosmogenic 11C nuclide plays a central role. 11C is produced underground in reactions induced by the residual cosmic muon flux. Experimental data available for the effective cross section for 11C by

Emmanuelle Dufour, Annette Calisti, Bernard Talin, Marco A. Gigosos

Studies of charge-charge (ion-ion, ion-electron, and electron-electron) coupling properties for ion impurities in an electron gas and for a two component plasma are carried out on the basis of a regularized electron-ion potential without short-range Coulomb divergence. This work is motivated in part by questions arising from recent spectroscopic measurements

Andras Vasy, Jared Wunsch

Let (X,g) be a metrically complete, simply connected Riemannian manifold with bounded geometry and pinched negative curvature, i.e. there are constants a>b>0 such that -a^2<K<-b^2 for all sectional curvatures K. Here bounded geometry is used in the sense that all covariant derivatives of the Riemannian curvature tensor are bounded and the injectivity radius

Erik Schnetter

I consider the initial-boundary-value-problem of nonlinear general relativistic vacuum spacetimes, which today cannot yet be evolved numerically in a satisfactory manner. Specifically, I look at gauge conditions, classifying them into gauge evolution conditions and gauge fixing conditions. In this terminology, a gauge fixing condition is a condition that rem

F. W. S. Lima, U. L. Fulco, R. N. Costa Filho

The stationary critical properties of the isotropic majority vote model on random lattices with quenched connectivity disorder are calculated by using Monte Carlo simulations and finite size analysis. The critical exponents $\gamma$ and $\beta$ are found to be different from those of the Ising and majority vote on the square lattice model and the critical no

Tuson Park, M. B. Salamon

The gap function in unconventional superconductors may vanish at points or lines in momentum space, permitting electronic excitations, termed nodal quasiparticles, to exist at temperatures well below the superconducting transition. In the vortex phase, the presence of nodal quasiparticles should be directly observable through the variation of the heat capaci

Piotr Bizoń, Arthur Wasserman

We show that the gravitating static soliton in the 2+1 dimensional O(3) $\sigma$ model does not exist in the presence of a negative cosmological constant.

M. Ablikim

A partial wave analysis is presented of $J/\psi \to \phi \pi ^+\pi ^-$ and $\phi K^+K^-$ from a sample of 58M $J/\psi$ events in the BES II detector. The $f_0(980)$ is observed clearly in both sets of data, and parameters of the Flatt\' e formula are determined accurately: $M = 965 \pm 8$ (stat) $\pm 6$ (syst) MeV/c$^2$, $g_1 = 165 \pm 10 \pm 15 $ MeV/c$^2$,

S. Blais-Ouellette, P. Amram, C. Carignan, R. Swaters

High resolution Fabry-Perot data of six spiral galaxies are presented. Those data extend the previous sample of spiral galaxies studied with high resolution 3D spectroscopy to earlier morphological types. All the galaxies in the sample have available HI data at 21 cm from the VLA or Westerbork. Velocity fields are analyzed and Halpha rotation curves are comp

Stefano Profumo, Kris Sigurdson, Piero Ullio, Marc Kamionkowski

We show that charged-particles decaying in the early Universe can induce a scale-dependent or `running' spectral index in the small-scale linear and nonlinear matter power spectrum and discuss examples of this effect in minimal supersymmetric models in which the lightest neutralino is a viable cold-dark-matter candidate. We find configurations in which the n