April 2002 arXiv papers — page 22

Malcolm Fairbairn, Michel H. G. Tytgat

Motivated by recent works of Sen and Gibbons, we study the evolution of a flat and homogeneous universe dominated by tachyon matter. In particular, we analyse the necessary conditions for inflation in the early roll of a single tachyon field.

Heng Fan, Keiji Matsumoto, Hiroshi Imai

We define the concurrence hierarchy as d-1 independent invariants under local unitary transformations in d-level quantum system. The first one is the original concurrence defined by Wootters et al in 2-level quantum system and generalized to d-level pure quantum states case. We propose to use this concurrence hierarchy as measurement of entanglement. This me

I. V. Tokatly, O. Pankratov

Using general local conservations laws we derive dispersion relations for edge modes in a slab of electron liquid confined by a symmetric potential. The dispersion relations are exact up to $λ^{2} q^{2}$, where $q$ is a wave vector and $λ$ is an effective screening length. For a harmonic external potential the dispersion relations are expressed in terms of t

Wang Xiang-bin

It is conjectured that the an entanglement output states from a beam splitter requires the nonclassicality in the input state(M.S. Kim, W. Son, V. Buzek and P. L. Knight, Phys. Rev. A, 65, 032323(2002)). Here we give a proof for this conjecture.

G. Akemann

A chiral random matrix model with complex eigenvalues is solved as an effective model for QCD with non-vanishing chemical potential. We derive new matrix model correlation functions which predict the local fluctuations of complex Dirac operator eigenvalues at zero virtuality. The parameter which measures the non-Hermiticity of the Dirac matrix is identified

Chen-Shan Chin

Passive random walker dynamics is introduced on a growing surface. The walker is designed to drift upward or downward and then follow specific topological features, such as hill tops or valley bottoms, of the fluctuating surface. The passive random walker can thus be used to directly explore scaling properties of otherwise somewhat hidden topological feature

Mirt Gramann, Ivan Suhhonenko

We investigate the dynamical state of superclusters in Lambda cold dark matter ($Λ$CDM) cosmological models, where the density parameter $Ω_0=0.2-0.4$ and $σ_8$ (the rms fluctuation on the $8h^{-1}$Mpc scale) is $0.7-0.9$. To study the nonlinear regime, we use N-body simulations. We define superclusters as maxima of the density field smoothed on the scale $R

Sergey Kudryavtsev

Log Enriques surfaces with delta=2 are classified.

Iver Brevik, Kazuo Ghoroku, Sergei D. Odintsov, Masanobu Yahiro

We address the localization of gravity on the Friedmann-Robertson-Walker type brane embedded in either $AdS_{5}$ or $dS_{5}$ bulk space,and derive two definite limits between which the value of the bulk cosmological constant has to lie in order to localize the graviton on the brane.The lower limit implies that the brane should be either $dS_{4}$ or 4d Minkow

Chris Quigg

Closing talk at Snowmass 2001: a summer study on the future of particle physics.

Toru Goto, Yasuhiro Okada, Yasuhiro Shimizu, Tetsuo Shindou

We investigate quark flavor signals in three different supersymmetric models, the minimal supergravity, the SU(5) SUSY GUT with right handed neutrinos, and the minimal supersymmetric standard model with U(2) flavor symmetry, in order to study physics potential of the present and future $B$ factories. We evaluate CP asymmetries in various B decay modes, $Δm_{

Holger Mack, Marc Bienert, Florian Haug, Frank S. Straub

We connect three phenomena of wave packet dynamics: Talbot images, revivals of a particle in a box and fractional revivals. The physical origin of these effects is deeply rooted in phase factors which are quadratic in the quantum number. We show that the characteristic structures in the time evolution of these systems allow us to factorize large integers.

Patrick Hayden, Richard Jozsa, Andreas Winter

We study the visible compression of a source E of pure quantum signal states, or, more formally, the minimal resources per signal required to represent arbitrarily long strings of signals with arbitrarily high fidelity, when the compressor is given the identity of the input state sequence as classical information. According to the quantum source coding theor

Tamás Geszti

A scenario is outlined for quantum measurement, assuming that self-sustaining classicality is the consequence of an attractive gravitational self-interaction acting on massive bodies, and randomness arises already in the classical domain. A simple solvable model is used to demonstrate that small quantum systems influence big ones in a mean-field way, offerin

X. X. Yi

This paper has been withdrawn because the first author submitted the paper without previously consulting the rest of the authors.

Stephen D. Bartlett, Barry C. Sanders, Benjamin T. H. Varcoe, Hubert de Guise

By encoding a qudit in a harmonic oscillator and investigating the infinite limit, we give an entirely new realization of continuous-variable quantum computation. The generalized Pauli group is generated by number and phase operators for harmonic oscillators. We describe a physical realization in terms of modes in a microwave cavity, coupled via a standard K

M. Hammes, D. Rychtarik, H. -C. Nägerl, R. Grimm

An optical microtrap is realized on a dielectric surface by crossing a tightly focused laser beam with an horizontal evanescent-wave atom mirror. The nondissipative trap is loaded with $\sim$$10^5$ cesium atoms through elastic collisions from a cold reservoir provided by a large-volume optical surface trap. With an observed 300-fold local increase of the ato

John Michael Williams

A proof is developed from first principles, independent of general relativity and of thermodynamics, that there exists a threshold acceleration above which radiation (real particle creation) from the vacuum must occur. The radiation is not expected to follow a Planckian distribution. PACS Codes: 03.65.Bz 04.70.-s 26.35.+c

Derek Teaney

We construct a hadronic equation of state consistent with chemical freezeout and discuss how such an equation of state modifies the radial and elliptic flow in a hydrodynamic + hadronic cascade model of relativistic heavy ion collisions at the SPS. Incorporating chemical freezeout does not change the relation between pressure and energy density. However, it

T. Niksic, D. Vretenar, P. Ring, G. A. Lalazissis

The phenomenon of shape coexistence is studied in the Relativistic Hartree-Bogoliubov framework. Standard relativistic mean-field effective interactions do not reproduce the ground state properties of neutron-deficient Pt-Hg-Pb isotopes. It is shown that, in order to consistently describe binding energies, radii and ground state deformations of these nuclei,

T. Falter, S. Leupold, U. Mosel

We explain the early onset of shadowing in nuclear photoabsorption within a multiple scattering approach and discuss its relation to in-medium modifications of the rho^0.

R. E. Borcherds, A. Barnard

These are notes from a 15 week course aimed at graduate mathematicians. They provide an essentially self-contained introduction to some of the ideas and terminology of QFT.

Christopher Connell, Benson Farb

In this paper we describe some recent applications of the barycenter method in geometry. This method was first used by Duady-Earle and later greatly extended by Besson-Courtois-Gallot in their solution of a number of long-standing problems, in particular in their proof of entropy rigidity for closed, negatively curved locally symmetric manifolds. Since there

Luis Fuentes Garcia, Manuel Pedreira Perez

We study the projective normality of a linearly normal special scroll R of degree d and speciality i over a smooth curve X of genus g. We relate it with the Clifford index of the base curve X. If d>=4g-2i-Cliff(X)+1, i>=3 and R is smooth, we prove that the projective normality of the scroll is equivalent to the projective normality of its directrix curve of

Carl Mueller, Roger Tribe

We give a new example of a measure-valued process without a density, which arises from a stochastic partial differential equation with a multiplicative noise term. This process has some unusual properties. We work with the heat equation with a random potential: u_t=Delta u+kuF. Here k>0 is a small number, and x lies in d-dimensional Euclidean space with d>2.

Niels Borne

Suppose given a Galois etale cover Y -> X of proper non-singular curves over an algebraically closed field k of prime characteristic p. Let H be its Galois group, and G any finite extension of H by a p-group P. We give necessary and sufficient conditions on G to be the Galois group of an etale cover of X dominating Y -> X.

Mihail N. Kolountzakis, Szilard Gy. Revesz

We study the following question posed by Turan. Suppose K is a convex body in Euclidean space which is symmetric with respect to the origin. Of all positive definite functions supported in K, and with value 1 at the origin, which one has the largest integral? It is probably the case that the extremal function is the indicator of the half-body convolved with

Eugene Polulyakh

We consider left shift transform S on the space $X=Σ^{\mathbb Z}$ of two-sided sequences over a compact alphabet $Σ$. We give an important and sufficient condition on $x \in X$ which guarantees the restriction of S onto orbit closure of x to be a Toeplitz flow.

Luis Fuentes Garcia, Manuel Pedreira Perez

We give a geometrical characterization of the ideal of quadrics containing a canonical curve with an involution. This implies to study involutions of rational normal scrolls and Veronese surfaces.

Andrew Hassell, Terence Tao

Suppose that $M$ is a compact Riemannian manifold with boundary and $u$ is an $L^2$-normalized Dirichlet eigenfunction with eigenvalue $λ$. Let $ψ$ be its normal derivative at the boundary. Scaling considerations lead one to expect that the $L^2$ norm of $ψ$ will grow as $λ^{1/2}$ as $λ\to \infty$. We prove an upper bound of the form $\|ψ\|_2^2 \leq Cλ$ for

Kapil Hari Paranjape

A result of Belyi can be stated as follows. Every curve defined over a number field can be expressed as a cover of the projective line with branch locus contained in a rigid divisor. We define the notion of geometrically rigid divisors in surfaces and then show that every surface defined over a number field can be expressed as a cover of the projective plane

Luis Fuentes Garcia, Manuel Pedreira Perez

We prove the existence of canonical scrolls; that is, scrolls playing the role of canonical curves. First of all, they provide the geometrical version of Riemann Roch Teorem: any special scroll is the projection of a canonical scroll and they allow to understand the classification of special scrolls in P3. Canonical scrolls correspond to the projective model

Antun Milas

We consider a class of weak modules for vertex operator algebras that we call logarithmic modules. We also construct nontrivial examples of intertwining operators between certain logarithmic modules for the Virasoro vertex operator algebra. At the end we speculate about some possible logarithmic intertwiners at the level $c=0$.

S. Arkhipov, D. Gaitsgory

Let $g$ be a semi-simple simply-connected Lie algebra and let $U_\ell$ be the corresponding quantum group with divided powers, where $\ell$ is an even order root of unity. Let in addition $u_\ell\subset U_\ell$ be the corresponding "small" quantum group. In this paper we establish the following relation between the categories of representations of $U

G. W. Delius, Rafael I. Nepomechie

We use boundary quantum group symmetry to obtain recursion formulas which determine nondiagonal solutions of the boundary Yang-Baxter equation (reflection equation) of the XXZ type for any spin j.

Saswat Sarangi, S. -H. Henry Tye

Towards the end of the brane inflationary epoch in the brane world, cosmic strings (but not texture, domain walls or monopoles) are copiously produced during brane collision. These cosmic strings are D$p$-branes with $(p-1)$ dimensions compactified. We elaborate on this prediction of the superstring theory description of the brane world. Using the data on th

Olaf Lechtenfeld, Warren Siegel

Covariant quantization of self-dual strings in 2+2 flat dimensions reduces them to their zero modes, a consequence of extended world-sheet supersymmetry. We demonstrate how to arrive at the same result more directly by employing a `double' light-cone gauge. An unconventional feature of this gauge is the removal of anticommuting degrees of freedom by comm

B. J. Short

We investigate the SU(N) Principal Chiral Model on a half-line with a particular set of boundary conditions (BCs). In previous work these BCs have been shown to correspond to boundary scattering matrices (K-matrices) which are representation conjugating and whose matrix structure corresponds to one of the symmetric spaces SU(N)/SO(N) or SU(N)/Sp(N). Starting

G. 't Hooft

In the first part of this lecture, the 1/N expansion technique is illustrated for the case of the large-N sigma model. In large-N gauge theories, the 1/N expansion is tantamount to sorting the Feynman diagrams according to their degree of planarity, that is, the minimal genus of the plane onto which the diagram can be mapped without any crossings. This holds

Z. W. Chong, M. Cvetic, G. W. Gibbons, H. Lu

We obtain first-order equations for G_2 holonomy of a wide class of metrics with S^3\times S^3 principal orbits and SU(2)\times SU(2) isometry, using a method recently introduced by Hitchin. The new construction extends previous results, and encompasses all previously-obtained first-order systems for such metrics. We also study various group contractions of

Tarek Ibrahim, Pran Nath

A calculus for the derivatives of the eigen values of the neutralino mass matrix with respect to the CP violating background fields is developed and used to compute the mixings among the CP even and the CP odd Higgs sectors arising from the inclusion of the neutralino sector consisting of the neutralino, the Z boson, and the neutral Higgs bosons ($χ^0_i-Z-h^

A. M. Badalian, B. L. G. Bakker, Yu. A. Simonov

A new physical mechanism is suggested to explain the universal depletion of high meson excitations. It takes into account the appearance of holes inside the string world sheet due to $q\bar{q}$ pair creation when the length of the string exceeds the critical value $R_1 \simeq 1.4$ fm. It is argued that a delicate balance between large $N_c$ loop suppression

F. Gianotti, M. L. Mangano, T. Virdee

We discuss the physics potential and the experimental challenges of an upgraded LHC running at an instantaneous luminosity of 10**35 cm-2s-1. The detector R&D needed to operate ATLAS and CMS in a very high radiation environment and the expected detector performance are discussed. A few examples of the increased physics potential are given, ranging from preci

A. Jokinen

We present analytical and numerical properties of the coherently rotating Affleck-Dine condensate formed along MSSM flat directions with the radiative corrections to the mass terms included. We analyse the pressure $p$ of the condensate, which is known to be negative if the potential grows slower than the field squared. We show that ellipticity of the orbit

D. Espriu, J. Manzano, P. Talavera

We clarify some aspects of the LSZ formalism and wave function renormalisation for unstable particles in the presence of electroweak interactions when mixing and CP violation are considered. We also analyse the renormalisation of the CKM mixing matrix which is closely related to wave function renormalisation. We critically review earlier attempts to define a

Chris Quigg

Opening talk at Snowmass 2001: a summer study on the future of particle physics.

Junji Hisano, Kiyotomo Kawagoe, Ryuichiro Kitano, Mihoko M. Nojiri

In the minimal supersymmetric standard model (MSSM) properties of the third generation sfermions are important from the viewpoint of discriminating the SUSY breaking models and in the determination of the Higgs boson mass. If gluinos are copiously produced at CERN LHC, gluino decays into tb through stop and sbottom can be studied using hadronic decays of the

J. Tabei, H. Hotta

On the evaluation of $\tanβ$ is revisited by the method of the renormalization group with the criteria of the bottom-tau unification in the SUSY SU(5) GUT model. Among the conventional supersymmetric theories, an energy-scale constant $M_{SUSY}$ is introduced by-hand to decouple the lower energy-scale region from the effects of the supersymmetric particles.

Maria R. Coluccia, J. A. Appel, G. Chiodini, D. C. Christian

We report on measurements performed on silicon pixel sensor prototypes exposed to a 200 MeV proton beam at the Indiana University Cyclotron Facility. The sensors are of n+/n/p+ type with multi-guard ring structures on the p+-side and p-stop electrode isolation on the n+-side. Electrical characterization of the devices was performed before and after irradiati

Dzero Collaboration

Based on 85 pb$^{-1}$ data of \ppbar collisions at $\sqrt{s}=1.8$ \tev\ collected using the DØdetector at Fermilab during the 1994-1995 run of the Tevatron, we present a direct measurement of the total decay width of the \wb\ boson, $Γ_W$. The width is determined from the transverse mass spectrum in the $W \to e+ν_e$ decay channel and found to be $Γ_W = 2.23

A. Lai, NA48 collaboration

New measurements of the $η$ and $K^0$ masses have been performed using decays to 3$π^0$ with the NA48 detector at the CERN SPS. Using symmetric decays to reduce systematic effects, the results $M(η) = 547.843\pm0.051$ MeV/c$^2$ and $M(K^0) = 497.625\pm0.031$ MeV/c$^2$ were obtained.

J. Mark Heinzle

This work is concerned with the finiteness problem for static, spherically symmetric perfect fluids in both Newtonian Gravity and General Relativity. We derive criteria on the barotropic equation of state guaranteeing that the corresponding perfect fluid solutions possess finite/infinite extent. In the Newtonian case, for the large class of monotonic equatio

Jun'ichi Yokoyama

Under the assumption that the cosmological constant vanishes in the true ground state with lowest possible energy density, we argue that the observed small but finite vacuum-like energy density can be explained if we consider a theory with two or more degenerate perturbative vacua, which are unstable due to quantum tunneling, and if we still live in one of s

Sanjeev S. Seahra

We study the dynamics of test particles and pointlike gyroscopes in 5D manifolds like those used in the Randall-Sundrum brane world and non-compact Kaluza-Klein models. Our analysis is based on a covariant foliation of the manifold using 3+1 dimensional spacetime slices orthogonal to the extra dimension, and is hence similar to the ADM 3+1 split in ordinary

Stuart E. Middleton, Harith Alani, David C. De Roure

Recommender systems learn about user preferences over time, automatically finding things of similar interest. This reduces the burden of creating explicit queries. Recommender systems do, however, suffer from cold-start problems where no initial information is available early on upon which to base recommendations. Semantic knowledge structures, such as ontol

Abhimanyu Das, Deboyjoti Dutta, Ahmed Helmy

In heterogeneous networks such as today's Internet, the differentiated services architecture promises to provide QoS guarantees through scalable service differentiation. Traffic marking is an important component of this framework. In this paper, we propose two new aggregate markers that are stateless, scalable and fair. We leverage stateless Active Queue

Kensuke Kobayashi, Hisashi Aikawa, Shingo Katsumoto, Yasuhiro Iye

We have measured transport through mesoscopic Aharonov-Bohm (AB) rings with two different four-terminal configurations. While the amplitude and the phase of the AB oscillations are well explained within the framework of the Landaur-Büttiker formalism, it is found that the probe configuration strongly affects the coherence time of the electrons, i.e., the dec

B. Lorenz, R. L. Meng, Y. Y. Xue, C. W. Chu

The superconducting ferromagnet RuSr2GdCu2O8 was investigated at high pressure. The intra-grain superconducting transition temperature, Tc, is resolved in ac-susceptibility as well as resistivity measurements. It is shown that the pressure shift of Tc is much smaller than that of other high-Tc compounds in a similar doping state. In contrast, the ferromagnet

Gregory Brown, M. A. Novotny, Per Arne Rikvold

A numerical model of single-domain nanoscale iron magnets fabricated using scanning-microscope-assisted chemical vapor deposition is simulated using finite-temperature micromagnetics. A Projective-dynamics method is used to determine the magnetization at the saddle point as a function of temperature. This magnetization is found to decrease linearly as the te

E. R. Hunt, P. M. Gade, Normand Mousseau

We measure stretched exponential behavior, exp(- (t/t_0)**beta), over many decades in a one-dimensional array of coupled chaotic electronic elements just above a crisis-induced intermittency transition. There is strong spatial heterogeneity and individual sites display a dynamics ranging from near power law ($β=0$) to near exponential ($β=1$) while the globa

S. F. Edwards, Moshe Schwartz

We study the transformation of the statistical mechanics of N particles to the statistical mechanics of fields, that are the collective coordinates, describing the system. We give an explicit expression for the functional Fourier transform of the Jacobian of the transformation from particle to collective coordinate and derive the Fokker-Planck equation in te

Hendrik Ulbricht, Jennah Kriebel, Gunnar Moos, Tobias Hertel

We present a study on the kinetics of xenon desorption from single-wall carbon nanotube (SWNT) bundles using thermal desorption spectroscopy (TDS). TD-spectra from SWNT samples show a broad desorption feature peaked at significantly higher temperature than the corresponding low-coverage desorption feature on graphite. The observations are explained using a c

Serge Galam, Bastien Chopard, Michel Droz

We discuss a cellular automata model to study the competition between an emergent better fitted species against an existing majority species. The model implement local fights among small group of individual and a synchronous random walk on a 2D lattice. The faith of the system, i.e. the spreading or disappearance of the species is determined by their initial

J. Gonzalez

We investigate the conditions in which superconductivity may develop in ropes of carbon nanotubes. It is shown that the interaction among a large number of metallic nanotubes favors the appearance of a metallic phase in the ropes, intermediate between respective phases with spin-density-wave and superconducting correlations. These arise in samples with about

Sergey V. Kuplevakhsky

In the recent Comment [V. M. Krasnov, Phys. Rev. B vol. 65, 096503 (2002)], the author claims to have ''disproved'' our theoretical conclusion [S. V. Kuplevakhsky, Phys. Rev. B vol. 60, 7496 (1999); Phys. Rev. B vol. 63, 054508 (2001)] that isolated Josephson vortices in layered superconductors and stacked junctions are absolutely unstable in

Hideki Abe, Kenji Yoshii

Electrolysis has been performed on a fused mixture of magnesium chloride, potassium chloride, and magnesium borate at 600 oC under an Ar atmosphere using a graphite anode and a Pt cathode. Magnetic measurements and X-ray diffractometry have revealed that the resultant deposit on the cathode contains a few tens molar percent of MgB2. A voltanmetric measuremen

P. Le Doussal, C. Monthus

The real-space renormalization group (RSRG) method introduced previously for the Brownian landscape is generalized to obtain the joint probability distribution of the subset of the important extrema at large scales of other one-dimensional landscapes. For a large class of models we give exact solutions obtained either by the use of constrained path-integrals

H. Kempa, P. Esquinazi, Y. Kopelevich

We show that the resistivity perpendicular $ρ_c$ and parallel $ρ_a$ to the basal planes of different graphite samples show similar magnetic-field-driven metal-insulator-transitions at a field $B_c \sim 0.1 T$ applied parallel to the c-axis. Our results demonstrate the universality of the recently found scaling in $ρ_a$ of graphite and indicate that the metal

T. Nakaegawa, Y. Ohta

Quantum Monte Carlo method is used to study the coupled spin-pseudospin Hamiltonian in one-dimension (1D) that models the charge-ordering instability of the anisotropic Hubbard ladder at quarter filling. We calculate the temperature dependence of the uniform spin susceptibility and the spin and charge excitation spectra of the system to show that there is a

Peter Scheidler, Walter Kob, Kurt Binder

Using molecular dynamics simulations we investigate the relaxation dynamics of a supercooled liquid close to a rough as well as close to a smooth wall. For the former situation the relaxation times increase strongly with decreasing distance from the wall whereas in the second case they strongly decrease. We use this dependence to extract various dynamical le

C. Bourbonnais, B. Guay, R. Wortis

We review some aspects of the renormalization group method for interacting fermions. Special emphasis is placed on the application of scaling theory to quasi-one-dimensional systems at non zero temperature. We begin by introducing the scaling ansatz for purely one-dimensional fermion systems and its extension when interchain coupling and dimensionality cross

Oleg Tchernyshyov, R. Moessner, S. L. Sondhi

In the highly frustrated pyrochlore magnet spins form a lattice of corner sharing tetrahedra. We show that the tetrahedral ``molecule'' at the heart of this structure undergoes a Jahn-Teller distortion when lattice motion is coupled to the antiferromagnetism. We extend this analysis to the full pyrochlore lattice by means of Landau theory and argue t

Y. Avishai, A. Golub, A. D. Zaikin

Electron transport between two superconductors through an Anderson impurity in the Kondo regime is investigated within the slave boson mean field approximation. The current, shot noise power and Fano factor are displayed versus the applied bias voltage in the subgap region and found to be strongly dependent on the ratio between the Kondo temperature $T_{K}$

S. B. Howell, R. Fried, P. Szkody, M. Sirk

We obtained EUV photometry, optical spectroscopy, and multi-color optical photometry for WX Cet during its 1998 November superoutburst. WX Cet is only the second short-period, low mass transfer CV (TOAD) to ever be observed in the EUV. Our determined superhump period is consistent with that found by Kato et al. (0.059 d) and we confirm that superhumps are gr

Ray Jayawardhana, Wayne S. Holland, Paul Kalas, Jane S. Greaves

We present new, high-sensitivity sub-millimeter observations towards 55 Cancri, a nearby G8 star with one, or possibly two, known planetary companion(s). Our 850 $μ$m map, obtained with the SCUBA instrument on the James Clerk Maxwell Telescope, shows three peaks of emission at the 2.5 mJy level in the vicinity of the star's position. However, the observe

Rennan Barkana, Abraham Loeb

We show that the gaseous halos of collapsed objects introduce a substantial cumulative opacity to ionizing radiation, even after the smoothly distributed hydrogen in the intergalactic medium has been fully reionized. This opacity causes a delay of around unity in redshift between the time of the overlap of ionized bubbles in the intergalactic medium and the

W. D. Watson, A. P. Sarma, M. S. Singleton

Calculations are performed to demonstrate the deviations from Gaussian that occur in the spectral line profiles of a linear maser as a result of the amplification process. Near-Gaussian profiles are presented for bright, interstellar 22 GHz water masers obtained from high resolution Very Long Baseline Array (VLBA) observations of W3 IRS 5. For the profiles t

Massimo Ricotti, Andrea Ferrara

Kinetic energy stored in ISM bulk/turbulent motions is a crucial ingredient to properly describe most properties of observed galaxies. By using Monte Carlo simulations, we investigate how this energy is injected by supernovae and dissipated via cloud collisions and derive the corresponding ISM velocity probability distribution function (PDF). The functional

E. Schinnerer, W. Maciejewski, N. Z. Scoville, L. A. Moustakas

The bulk of the molecular line emission in the double barred galaxy NGC4303 as observed in its CO(1-0) line with the OVRO mm-interferometer comes from two straight gas lanes which run north-south along the leading sides of the large-scale primary bar. Inside a radius of ~ 400 pc the molecular gas forms a spiral pattern which, for the northern arm, can be tra

V. Motta, E. Mediavilla, J. A. Munoz, E. Falco

We determine the extinction curve in the z_l=0.83 lens galaxy of the gravitational lens SBS0909+532 from the wavelength dependence of the flux ratio between the lensed quasar images (z_s=1.38) from 3400 to 9200Å. It is the first measurement of an extinction curve at a cosmological distance of comparable quality to those obtained within the Galaxy. The extinc

Roland Bacon, Martin Bureau, Michele Cappellari, Yannick Copin

We present the SAURON project, which is aimed at studying the morphology, two-dimensional kinematics and stellar populations of a representative sample of elliptical galaxies and spiral bulges. SAURON, a dedicated integral-field spectrograph that is optimized for wide-field observations and has high throughput, was built in Lyon and is now operated at the WH

Paola Caselli

Deuterium fractionation in molecular ions, in particular HCO+, has been extensively used to estimate the degree of ionization in molecular clouds. This paper reviews recent work on ionization degree in homogeneous clouds. We will show that the N(DCO+)/N(HCO+) column density ratio furnishes a measurement of x(e) only in regions where CO is not significantly d

J. Patterson, G. Masi, M. Richmond, B. Martin

We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23-year slumber at V=15.5, the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption lasting 25 days. The return to quiescence was punctuated by 12 small eruptions, of ~1 mag amplitude and 2 day recurrence time; these "ech

David Skillman, Thomas Krajci, Edward Beshore, Joseph Patterson

We report photometry of 1RXS J232953.9+062814, a recently discovered dwarf nova with a remarkably short 64.2-minute orbital period. In quiescence, the star's light curve is that of a double sinusoid, arising from the "ellipsoidal" distortion of the Roche-lobe-filling secondary. During superoutburst, common superhumps develop with a period 3-4% lo

L. Lopez-Martin, J. A. Lopez, C. Esteban, R. Vazquez

The kinematics and physical conditions of the bipolar planetary nebula M 2-48 are analysed from high and low dispersion long-slit spectra. Previous CCD narrow-band optical observations have suggested that this nebula is mainly formed by a pair of symmetric bow-shocks, an off-center semi-circular shell, and an internal bipolar structure. The bipolar outflow h

L. Formiggini, N. Brosch, E. Almoznino, S. Bowyer

We present results of an analysis of a UV image in the direction of Ophiuchus, obtained with the FAUST instrument. The image contains 228 UV sources. Most of these were identified as normal early-type stars through correlations with cataloged objects. For the first time in this project we identified UV sources as such stars by selecting suitable candidates i

J. A. Eilek, P. N. Arendt, T. H. Hankins, J. C. Weatherall

The pulsar magnetosphere contains a strongly magnetized, relativistic plasma. We need to understand the physics of that plasma if we want to connect the data to the models. Our group in Socorro is mixing theory and observations in order to study the radio-loud pulsar plasma. In this paper we report on several aspects of our current work.

Cheongho Han

If a source star is gravitationally microlensed by a multiple lens system, the resulting light curve can have significant deviations from the standard form of a single lens event. The chance to produce significant deviations becomes important when the separations between the component lenses are equivalent to the combined angular Einstein ring radius of the

D. Porquet, R. Mewe, J. S. Kaastra, J. Dubau

The calculations of the ratios of the Helium-like ion X-ray lines from C V to Si XIII are revisited in order to apply the results to density, temperature and ionization process diagnostics of data from high-resolution spectroscopy of the new generation of X-ray satellites: Chandra and XMM-Newton. Comparing to earlier computations, Porquet & Dubau (2000), the

J. J. Monaghan

In this paper an SPH version of the alpha turbulence model devised by Holm and his colleagues is formulated for compressible flow with a resolution that varies in space and time. The alpha model involves two velocity fields. One velocity field is obtained from the momentum equation, the other by averaging this velocity field as in the version of SPH called X

W. Aoki, H. Ando, S. Honda, M. Iye

We have obtained a high resolution (R~90,000) spectrum of the carbon- and s-process-element-rich, very metal-poor ([Fe/H]=-2.7) subgiant LP625-44, as well as that of HD140283 (a metal-poor subgiant with normal abundance ratio) for comparison, with the High Dispersion Spectrograph (HDS) for the Subaru Telescope for detailed abundance study. The oxygen abundan

M. E. Cates, D. A. Head, A. Ajdari

We study a simple scalar constitutive equation for a shear-thickening material at zero Reynolds number, in which the shear stress σis driven at a constant shear rate \dotγand relaxes by two parallel decay processes: a nonlinear decay at a nonmonotonic rate R(σ_1) and a linear decay at rate λσ_2. Here σ_{1,2}(t) = τ_{1,2}^{-1}\int_0^tσ(t')\exp[-(t-t')

Bo-Qiang Ma, Di Qing, Ivan Schmidt

The nucleon axial vector form factor is investigated in a light-cone quark spectator diquark model, in which Melosh rotations are applied to both the quark and vector diquark. It is found that this model gives a very good description of available experimental data and the results have very little dependence on the parameters of the model. The relation betwee

N. J. Nunes, E. J. Copeland

We analyse the mechanism of quintessential inflation in brane world scenarios for a number of particle physics inspired scalar potentials. We constrain the parameter space of those scalar potentials and comment on the likelihood that we could discriminate these models from standard inflation, based on upcoming large scale structure and cosmic microwave backg

Klaus Behrndt

A 7-manifold with G_2 holonomy can be constructed as a R^3 bundle over a quaternionic space. We consider a quaternionic base space which is singular and its metric depends on three parameters, where one of them corresponds to an interpolation between S^4 and CP^2 or its non-compact analogs. This 4-d Einstein space has four isometries and the fixed point set

Werner Kerler

Instead of the Ginsparg-Wilson (GW) relation we only require generalized chiral symmetry and show that this results in a larger class of Dirac operators describing massless fermions, which in addition to GW fermions and to the ones proposed by Fujikawa includes many more general ones. The index turns out to depend solely on a basic unitary operator. We use s

Peter G. Jonker, Mariano Mendez, Michiel van der Klis

Recent observations of the low-mass X-ray binary 4U 1636-53 with the Rossi X-ray Timing Explorer show, for the first time, a kiloHertz quasi-periodic oscillation (kHz QPO) peak separation that exceeds the neutron star spin frequency as inferred from burst oscillations. This strongly challenges the sonic-point beat frequency model for the kHz QPOs found in lo

Alexander G. Kyriakos

There is a certainty that the modern (Copenhagen's) interpretation of quantum mechanics is correct. However, the some physicist had the opinion that the modern quantum mechanics is a phenomenological theory. The suggested theory is the new quantum mechanics interpretation that is entirely according to the modern interpretation and gives a number of resul

Herschel S. Pilloff, Marko Horbatsch

In the course of exploring some aspects of atom guiding in a hollow, optical fiber, a small negative potential energy well was found just in front of the repulsive or guiding barrier. This results from the optical dipole and the van der Waals potentials. The ground state for atoms bound in this negative potential well was determined by numerically solving th

A. D. Alhaidari

We find solutions for a linear deformation of the symmetric three-term recursion relation. The orthogonal polynomials of the first and second kind associated with the deformed relation are obtained. The new density (weight) function is written in terms of the original one and the deformation parameters.