February 2002 arXiv papers — page 8

F. Bonechi, S. De Bievre

We show that in the semi-classical limit the eigenfunctions of quantized ergodic symplectic toral automorphisms can not concentrate in measure on a finite number of closed orbits of the dynamics. More generally, we show that, if the pure point component of the limit measure has support on a finite number of such orbits, then the mass of this component must b

Tetsu Masuda

A determinant formula for a class of algebraic solutions to Painlevé VI equation (P$_{\rm VI}$) is presented. This expression is regarded as a special case of the universal characters. The entries of the determinant are given by the Jacobi polynomials. Degeneration to the rational solutions of P$_{\rm V}$ and P$_{\rm III}$ is discussed by applying the coales

Peter M. Alberti

The notion of partial fidelities as invented recently by A.Uhlmann for pairs of finite dimensional density matrices will be extended to the vN-algebraic context and is considered and thoroughly discussed in detail from a mathematical point of view. Especially, in the case of semifinite vN-algebras formulae and estimates for the partial fidelity between the f

W A Majewski

In the paper we present the new approach to Kolmogorov-Sinai entropy and its quantization. Our presentation stems from an application of the Choquet theory to the theory of decompositions of states and therefore, it resembles our rigorous description of entanglement of formation

W A Majewski

In this paper we present the novel qualities of entanglement of formation for general (so also infinite dimensional) quantum systems and we introduce the notion of coefficient of quantum correlations. Our presentation stems from rigorous description of entanglement of formation.

Johannes Huebschmann, Jim Stasheff

We construct a solution of the master equation by means of standard tools from homological perturbation theory under just the hypothesis that the ground field be of characteristic zero, thereby avoiding the formality assumption of the relevant Lie algebra. To this end we endow the homology H(g) of any differential graded Lie algebra g with an sh-Lie structur

Ján Minác, John Swallow

For fields F of characteristic not p containing a primitive $p$th root of unity, we determine the Galois module structure of the group of $p$th-power classes of K for all cyclic extensions K/F of degree p.

Fedor Bogomolov, Yuri Tschinkel

We study correspondences between algebraic curves defined over the separable closure of $\Q$ or $\F_p$.

Viktor Bekkert, Georgia Benkart, Vyacheslav Futorny

We investigate weight modules for finite and infinite Weyl algebras, classifying all such simple modules. We also study the representation type of the blocks of locally-finite weight module categories and describe indecomposable modules in tame blocks.

Fedor Bogomolov, Yuri Tschinkel

We construct examples of simply connected nonalgebraic symplectic fourfolds with a prescribed number of nonintersecting symplectic curves with positive self-intersections.

M. L. Barberis, I. Dotti

We obtain a characterization of the real Lie algebras admitting abelian complex structures in terms of certain affine Lie algebras $\frak a \frak f \frak f (A)$, where $A$ is a commutative algebra. These affine Lie algebras are natural generalizations of $\frak a \frak f \frak f (\Bbb C)$ and the corresponding Lie groups are complex affine manifolds. It turn

T. Mansour

Recently, Babson and Steingrimsson (see \cite{BS}) introduced generalized permutations patterns that allow the requirement that two adjacent letters in a pattern must be adjacent in the permutation. In this paper we study the generating functions for the number of permutations on $n$ letters avoiding a generalized pattern $ab\mn c$ where $(a,b,c)\in S_3$, an

T. Mansour

A natural generalization of single pattern avoidance is subset avoidance. A complete study of subset avoidance for the case k=3 is carried out in [SS]. For k>3 situation becomes more complicated, as the number of possible cases grows rapidly. Recently, several authors have considered the case of general k when T has some nice algebraic properties. Barcucci,

Steven Duplij, Wladyslaw Marcinek

A proposal of the concept of $n$-regular obstructed categories is given. The corresponding regularity conditions for mappings, morphisms and related structures in categories are considered. An n-regular TQFT is introduced. It is shown the connection of time reversibility with the regularity.

Andrew Tetenov, Ivan Davydkin

If the system S of contracting similitudes on $ R^2$ satisfies open convex set condition, then the set F of extreme points of the convex hull $\tilde{K}$ of it's invariant self-similar set K has Hausdorff dimension 0 . If, additionally, all the rotation angles of the similitudes are commensurable with $π$, then the set F is finite and the convex hull $\t

Won Taek Song

We show that the Lawrence--Krammer representation is unitary. We explicitly present the non-singular matrix representing the sesquilinear pairing invariant under the action. We show that reversing the orientation of a braid is equivalent to the transposition of its Lawrence--Krammer matrix followed by a certain conjugation. As corollaries it is shown that th

Dimitry Leites

For every nonholonomic manifold, i.e., manifold with nonintegrable distribution, the analog of the Riemann tensor is introduced. It is calculated here for the contact and Engel structures: for the contact structure it vanishes (another proof of Darboux's canonical form); for the Engel distribution the target space of the tensor is of dimension 2. In part

R. Kashaev, N. Reshetikhin

Holonomy R-matrices parametrized by finite-dimensional representations are constructed for quantized universal enveloping algebras of simple Lie algebras at roots of 1.

Juan-Pablo Ortega

We generalize the notions of dual pair and polarity introduced by S. Lie and A. Weinstein in order to accommodate very relevant situations where the application of these ideas is desirable. The new notion of polarity is designed to deal with the loss of smoothness caused by the presence of singularities that are encountered in many problems. We study in deta

Sergei V. Shabanov

A low energy bound in a class of chiral solitonic field theories related the infrared physics of the SU(N) Yang-Mills theory is established.

A. V. Kartavtsev

Bogolubov's chain of equations method for temperature Wightman functions is suggested for investigation of relativistic phase transition. The chain equations for the Wightman functions forming momentum--energy tensor are obtained. It is clarified that structure of the chain equations determines the basis approximation (the Hartree - Fock approximation) a

Robert H. Brandenberger, Jerome Martin

Following a self-contained review of the basics of the theory of cosmological perturbations, we discuss why the conclusions reached in the recent paper by Kaloper et al are too pessimistic estimates of the amplitude of possible imprints of trans-Planckian (string) physics on the spectrum of cosmic microwave anisotropies in an inflationary Universe. It is sho

Y. Brihaye, A. Chakrabarti, D. H. Tchrakian

We consider the superposition of the first two members of the gravitational hierarchy (Einstein plus first Gauss-Bonnet(GB)) interacting with the superposition of the first two members of the $SO_{(\pm)}(d)$ Yang--Mills hierarchy, in $d$ dimensions. Such systems can occur in the low energy effective action of string theory. Particle-like solutions %for the s

J. W. Moffat

We construct an eleven-dimensional superspace with superspace coordinates and formulate a finite M-theory using non-anticommutative geometry. The conjectured M-theory has the correct eleven-dimensional supergravity low energy limit. We consider the problem of finding a stable finite M-theory which has de Sitter space as a natural ground state, and the proble

C. F. Berger, E. L. Berger, P. C. Bhat, J. M. Butterworth

Conventional cone jet algorithms arose from heuristic considerations of LO hard scattering coupled to independent showering. These algorithms implicitly assume that the final states of individual events can be mapped onto a unique set of jets that are in turn associated with a unique set of underlying hard scattering partons. Thus each final state hadron is

F. Maltoni, D. Rainwater, S. Willenbrock

We study the signal and background for the process tth, h->WW at the LHC and a 100 TeV VLHC. Signals are studied in two-, three-, and four-lepton final states. We find a statistical uncertainty in the top-quark Yukawa coupling at the LHC of 16%, 8%, 12% for m_h = 130, 160, 190 GeV, respectively. The statistical uncertainty at the VLHC is likely to be negligi

J. E. Palomar

We make use of recent accurate results obtained for the pion and kaon vector form factors within a chiral unitary approach in order to calculate the decay widths of the $τ$ lepton to these mesons and also to evaluate the contribution of this two mesons to the anomalous magnetic moment of the muon, the running of the fine structure constant and the muonium hy

C. S. Fischer, R. Alkofer

We present approximate solutions for the gluon and ghost propagators as well as the running coupling in Landau gauge Yang-Mills theories. We solve the corresponding Dyson-Schwinger equations in flat Euclidean space-time without any angular approximation. This supplements recently obtained results employing a four-torus, i.e. a compact space-time manifold, as

Petros D. Draggiotis, Ronald H. P. Kleiss, Costas G. Papadopoulos

The advent of high-energy hadron colliders necessitates efficient and accurate computation of multi-jet production processes, both as QCD processes in their own right and as backgrounds for other physics. The algorithm that performs these tasks and a brief numerical study of multi-jet processes are presented.

Stephan Narison

We review the present status for the determinations of the light and heavy quark masses, the light quark chiral condensate and the decay constants of light and heavy-light (pseudo)scalar mesons from QCD spectral sum rules (QSSR). Bounds on the light quark running masses at 2 GeV are found to be: 6 MeV<(m_d+m_u)(2)<11 MeV and 71 MeV<m_s(2)<148 MeV. The agreem

C. Blöchinger, M. Carena, J. Ellis, H. Fraas

We update theoretical studies of the physics opportunities presented by mu+mu- Higgs factories. Interesting measurements of the Standard Model Higgs decays into {\bar b}b, tau+tau- and WW* may be possible if the Higgs mass is less than about 160 GeV, as preferred by the precision electroweak data, the mass range being extended by varying appropriately the be

Tomoko ASAGA, Takehisa Fujita

Employing generalized Schiff&#39;s transformation on electric dipole moments (EDM) in quantum field theory, we show that the chromoelectric EDM lagrangian density is transformed into the electric EDM term with a new coefficient. Under the new constraint on the EDM operators, the neutron EDM can be described by a unique combination of electric EDM $d_f$ and c

Naoyuki Haba, Nobuhito Maru

We discuss the decoupling solution to SUSY flavor problem in the fat brane scenario. We present a simple model to yield the decoupling sfermion spectrum in a five dimensional theory. Sfermion masses are generated by the overlap between the wave functions of the matter fields and the chiral superfields on the SUSY breaking brane. Two explicit examples of the

A. Grigoriev, A. Lobanov, A. Studenikin

The Lorentz invariant formalism for description of neutrino flavour oscillations in moving matter is developed. It is shown that the matter motion with relativistic speed can sufficiently change the matter term in the neutrino effective potential. In the case of matter motion parallel to neutrino propagation, matter effects in neutrino flavour oscillations a

G. Calderini

Using 22.7 million BBbar events recorded with the BABAR detector, the inclusive branching fractions for the production of J/psi, psi(2S) and Chi_c in B decays are presented. Combining the charmonium state with a K+-, K0, K*+-, K*0 or neutral pion, B decays are reconstructed exlusively and branching fractions are determined. A preliminary study is also presen

M. Veltri

Nuclear effects in \numucc interactions with carbon nuclei have been studied by using backward going protons and $π^-$. Detailed analyses, of the momentum distributions and of the production rates, have been carried out in order to understand the mechanism producing these particles. The backward proton data have been compared with the predictions of the rein

The NA49 Collaboration, S. V. Afanasiev

Results of the production of Xi and Xi-bar hyperons in central Pb+Pb interactions at 158 GeV/c per nucleon are presented. This analysis utilises a global reconstruction procedure, which allows a measurement of 4pi integrated yields to be made for the first time. Inverse slope paramters, which are determined from an exponential fit to the transverse mass spec

A. E. Motter, P. S. Letelier

A recent paper by Castagnino, Giacomini and Lara concludes that there is no chaos in a conformally coupled closed Friedmann-Robertson-Walker universe, which is in apparent contradiction with previous works. We point out that although nonchaotic the quoted system is nonintegrable.

Marcelo Salgado

The linear approximation of scalar-tensor theories of gravity is obtained in the physical (Jordan) frame under the 4+0 (covariant) and 3+1 formalisms. Then the weak-field limit is analyzed and the conditions leading to significant deviations of the $1/r^{2}$ Newton&#39;s law of gravitation are discussed. Finally, the scalarization effects induced by these th

S. Brian Edgar, A. Hoglund

In this paper it is shown that a Lanczos potential for the Weyl curvature tensor does not exist for all spaces of dimension $n\geq 7$.

T. Padmanabhan

Euclidean continuation of several Lorentzian spacetimes with horizons requires treating the Euclidean time coordinate to be periodic with some period $β$. Such spacetimes (Schwarzschild, deSitter,Rindler .....) allow a temperature $T=β^{-1}$ to be associated with the horizon. I construct a canonical ensemble of a subclass of such spacetimes with a fixed valu

Carlo Rovelli

I illustrate a simple hamiltonian formulation of general relativity, derived from the work of Esposito, Gionti and Stornaiolo, which is manifestly 4d generally covariant and is defined over a finite dimensional space. The spacetime coordinates drop out of the formalism, reflecting the fact that they are not related to observability. The formulation can be in

T. Padmanabhan

The notions of temperature, entropy and `evaporation&#39;, usually associated with spacetimes with horizons, are analyzed using general approach and the following results, applicable to different spacetimes, are obtained at one go. (i) The concept of temperature associated with the horizon is derived in a unified manner and is shown to arise from purely kine

Martin Bojowald

Isotropic models in loop quantum cosmology allow explicit calculations, thanks largely to a completely known volume spectrum, which is exploited in order to write down the evolution equation in a discrete internal time. Because of genuinely quantum geometrical effects the classical singularity is absent in those models in the sense that the evolution does no

C. Kohler

Using a non-Riemannian geometry that is adapted to the 4+1 decomposition of space-time in Kaluza-Klein theory, the translational part of the connection form is related to the electromagnetic vector potential and a Stueckelberg scalar. The consideration of a five-dimensional gravitational action functional that shares the symmetries of the chosen geometry lea

I. Radinschi, I-Ching Yang

We use the Møller energy-momentum complex to calculate the energy of the Melvin magnetic universe. The energy distribution depends on the magnetic field.

Carlo Rovelli

Is there a version of the notions of &#34;state&#34; and &#34;observable&#34; wide enough to apply naturally and in a covariant manner to relativistic systems? I discuss here a tentative answer.

Lars Andersson, Vincent Moncrief

The Einstein evolution equations are studied in a gauge given by a combination of the constant mean curvature and spatial harmonic coordinate conditions. This leads to a coupled quasilinear elliptic--hyperbolic system of evolution equations. We prove that the Cauchy problem is locally strongly well--posed and that a continuation principle holds. For initial

Satyanarayana R Valluri, Soujanya Vadapalli, Kamalakar Karlapalem

In optimizing queries, solutions based on AND/OR DAG can generate all possible join orderings and select placements before searching for optimal query execution strategy. But as the number of joins and selection conditions increase, the space and time complexity to generate optimal query plan increases exponentially. In this paper, we use join graph for a re

Paul M. Grant, Thomas P. Sheahen

It is generally argued that for high-temperature superconductors (HTS) to be cost-competitive in power applications, the wire will have to sell for about $10 per kiloampere meter ($10/kAm) for operation at 77 K (e.g., NbTi costs around $1/kAm and Nb3Sn around $8, each at 4.2 K). Given what is already known about the critical current performance of Pb-stabili

Daniel C. Hong, Paul V. Quinn, Stefan Luding

Canul-Chay et al. [1] have conducted the segregation experiment of binary granular mixtures in a bed and subjected the bed to vibration. They report that the reverse Brazil-Nut phenomenon (RBNP) was never observed in their experiments and thus conclude that such does not exist. However, we have clearly demonstrated in [2] by Molecular Dynamics simulations th

Daniel C. Hong, Paul V. Quinn, Stefan Luding

We find it absurd that Walliser [1] essentially used the same analysis and obtained identical results as reported in [3], yet arrived at different conclusions. Namely, based on an incomplete theory and using erroneous arguments, he not only disputes the original results [2], but also claims them wrong. A more complete theory and much more detailed studies we

Joshua Goodman

This is the extended version of a Comment submitted to Physical Review Letters. I first point out the inappropriateness of publishing a Letter unrelated to physics. Next, I give experimental results showing that the technique used in the Letter is 3 times worse and 17 times slower than a simple baseline. And finally, I review the literature, showing that the

S. M. Gatica, M. M. Calbi, M. W. Cole

We employ a simple model to describe the phase behavior of 4He and Ar in a hypothetical porous material consisting of a regular array of infinitely long, solid, parallel cylinders. We find that high porosity geometries exhibit two transitions: from vapor to film and from film to capillary condensed liquid. At low porosity, the film is replaced by a ``necking

S. A. Vitkalov, M. P. Sarachik, T. M. Klapwijk

In high-mobility silicon MOSFET&#39;s, the $g^*m^*$ inferred indirectly from magnetoconductance and magnetoresistance measurements with the assumption that $g^*μ_BH_s=2E_F$ are in surprisingly good agreement with $g^*m^*$ obtained by direct measurement of Shubnikov-de Haas oscillations. The enhanced susceptibility $χ^* \propto (g^*m^*)$ exhibits critical beh

S. A. Gardiner

I consider general connections between chaotic and quantum chaotics dynamics in single particles, and the effect of adding comparable ``chaos-inducing&#39;&#39; potentials to a Bose-condensed system, considering in particular concepts of integrability and the effect of particle loss from the condensate mode.

David E. Logan, Nigel L. Dickens

Single-particle dynamics of the Anderson impurity model in the presence of a magnetic field $H$ are considered, using a recently developed local moment approach that encompasses all energy scales, field and interaction strengths. For strong coupling in particular, the Kondo scaling regime is recovered. Here the frequency ($ω/ω_{\rm K}$) and field ($H/ω_{\rm

Hagen Kleinert, Axel Pelster, Mihai V. Putz

We develop a convergent variational perturbation theory for conditional probability densities of Markov processes. The power of the theory is illustrated by applying it to the diffusion of a particle in an anharmonic potential.

P. Kacman, J. Blinowski, H. Kepa, T. M. Giebultowicz

The interlayer spin correlations in the magnetic/non-magnetic semiconductor superlattices are reviewed. The experimental evidences of interlayer exchange coupling in different all-semiconductor structures, based on neutronographic and magnetic studies, are presented. A tight-binding model is used to explain interaction transfer across the non-magnetic block

J. J. Palacios, A. J. Perez-Jimenez, E. Louis, E. SanFabian

We present a first-principles numerical implementation of Landauer formalism for electrical transport in nanostructures characterized down to the atomic level. The novelty and interest of our method lies essentially on two facts. First of all, it makes use of the versatile Gaussian98 code, which is widely used within the quantum chemistry community. Secondly

A. V. Ruban, S. I. Simak, P. A. Korzhavyi, H. L. Skriver

A quantitative description of the configurational part of the total energy of metallic alloys with substantial atomic size difference cannot be achieved in the atomic sphere approximation: It needs to be corrected at least for the multipole moment interactions in the Madelung part of the one-electron potential and energy. In the case of a random alloy such i

A. V. Ruban, H. L. Skriver

We have used the locally self-consistent Green&#39;s function (LSGF) method in supercell calculations to establish the distribution of the net charges assigned to the atomic spheres of the alloy components in metallic alloys with different compositions and degrees of order. This allows us to determine the Madelung potential energy of a random alloy in the si

F. Ferlaino, P. Maddaloni, S. Burger, F. S. Cataliotti

The macroscopic coherent tunneling through the barriers of a periodic potential is used as an atomoptical filter to separate the condensate and the thermal components of a $^{87}$Rb mixed cloud. We condense in the combined potential of a laser standing-wave superimposed on the axis of a cigar-shape magnetic trap and induce condensate dipole oscillation in th

T. Terashima, T. Matsumoto, C. Terakura, S. Uji

The ac susceptibility and de Haas-van Alphen (dHvA) effect in UGe$_2$ are measured at pressures {\it P} up to 17.7 kbar for the magnetic field {\it B} parallel to the {\it a} axis, which is the easy axis of magnetization. Two anomalies are observed at {\it B$_x$}({\it P}) and {\it B}$_m$({\it P}) ({\it B$_x$} $>$ {\it B}$_m$ at any {\it P}), and the {\it P}-

S. Zhang, P. M. Levy, A. Fert

The mechanisms of the magnetization switching of magnetic multilayers driven by a current are studied by including exchange interaction between local moments and spin accumulation of conduction electrons. It is found that this exchange interaction leads to two additional terms in the Landau-Lifshitz-Gilbert equation: an effective field and a spin torque. Bot

J. A. Verges, V. Martin-Mayor, L. Brey

We present a single-orbital double-exchange model, coupled with cooperative phonons (the so called breathing-modes of the oxygen octahedra in manganites). The model is studied with Monte Carlo simulations. For a finite range of doping and coupling constants, a first-order Metal-Insulator phase transition is found, that coincides with the Paramagnetic-Ferroma

Z. Ivezic, K. Menou, M. Strauss, G. R. Knapp

We discuss the optical and radio properties of 30,000 FIRST sources positionally associated with an SDSS source in 1230 deg$^2$ of sky. The majority (83%) of the FIRST sources identified with an SDSS source brighter than r=21 are optically resolved. We estimate an upper limit of 5% for the fraction of quasars with broad-band optical colors indistinguishable

T. Jackson, Z. Ivezic, G. R. Knapp

We study the Galactic distribution of ~10,000 Asymptotic Giant Branch (AGB) stars selected by IRAS colors and variability index. The distance to each star is estimated by assuming a narrow luminosity function and a model-derived bolometric correction. The characteristic AGB star luminosity, L_AGB, is determined from the condition that the highest number dens

M. Nenkova, Z. Ivezic, M. Elitzur

Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central source, giving rise to Seyfert 1 line spectrum for pole-on viewing and Seyfert 2 characteristics in edge-on sources. Although the observed IR is in broad agreement with this scheme, the behavior of the 10 micron silicate feature and the width of the far-IR emi

Philip A. Hughes, Mark A. Miller, G. Comer Duncan

We describe a new numerical 3D relativistic hydrodynamical code, the results of validation tests, and a comparison with earlier, 2D studies. The 3D code has been used to study the deflection and precession of relativistic flows. We find that even quite fast jets (gamma~10) can be significantly influenced by impinging on an oblique density gradient, exhibitin

J. B. Hutchings, D. Frenette, R. Hanisch, J. Mo

We report on deep imaging in 2 filters with the PC2 camera of HST, of five QSOs at redshift ~2, with a range of optical and radio luminosity. The observations included a suite of PSF observations which were used to construct new PSF models, described elsewhere by Dumont et al. The new PSF models were used to remove the QSO nucleus from the images. We find th

D. Pourbaix, D. Nidever, C. McCarthy, R. P. Butler

New radial velocities of alpha Cen A & B obtained in the framework the Anglo-Australian Planet Search programme as well as in the CORALIE programme are added to those by Endl et al. (2001) to improve the precision of the orbital parameters. The resulting masses are 1.105+/-0.0070 MSun and 0.934+/-0.0061 MSun for A and B respectively. The factors limiting how

E. Pancino, L. Pasquini, V. Hill, F. R. Ferraro

We have obtained high-resolution, high S/N spectra for six red giants in omega Cen: three belonging to the recently discovered, metal-rich Red Giant Branch (RGB-a, Pancino et al. 2000) and three to the metal intermediate population (RGB-MInt). Accurate Iron, Copper and alpha-elements (Ca and Si) abundances have been derived and discussed. In particular, we h

K. -I. Nishikawa, S. Koide, K. Shibata, T. Kudoh

We have performed a first fully 3-D GRMHD simulation with Schwarzschild black hole with a free falling corona. The initial simulation results show that a jet is created as in previous axisymmetric simulations. However, the time to generate the jet is longer than in the 2-D simulations. We expect that due to the additional azimuthal dimension the dynamics of

F. Hroch, M. Basny

We present new photometric observations of RV Tri. A complete light curve was obtained in the R and V filters. These light curves were processed by the Wilson-Devinney (WD) code and the FOTEL to get solution of this eclipsing binary system. We discuss characteristics of the system and compare our model with a previous calculation. Our observations of primary

D. Grupe, H. -C Thomas

We report the results of near infrared observations of 19 soft X-ray selected AGN. The goal of the observations was to search for strong, narrow Paschen-alpha or Brackett-gamma emission lines, as a sign of nuclear starbursts. We found Pa-alpha emission in the spectra of 11 sources and Br-gamma in at least five. Strong NIR emission has been found in two sourc

G. Risaliti

We present the analysis of 31 observations of 20 bright Compton thin Seyfert 2s, in the 0.1-200 keV band, performed with the BeppoSAX satellite. The sample consists of all Seyfert 2s in the BeppoSAX public archive, with a 2-10 keV flux higher than 5x10^(-12) erg/cm^2/s. The good statistics available and the broad energy band permit a detailed study of the ma

O. Vallejo, J. Braine, A. Baudry

We present high resolution CO(1-0) interferometric observations and deep HST B-V-I images of the flocculent isolated Sc type spiral NGC 4414. The goal is to determine the stellar mass-to-light (M/L) ratio in a galactic disk. The stars are seen without a dust screen, the central gas mass is very low (undetected), and we show that the dark matter is negligible

R. N. Proctor, A. E. Sansom

We present line-strengths and kinematics from the central regions of 32 galaxies with Hubble types ranging from E to Sbc. Spectral indices, based on the Lick system, are measured in the optical and near infra-red (NIR). The 24 indices measured, in conjunction with models of the effects of varying abundance ratios, permit the breaking of age/metallicity degen

M. Bruscoli, M. Tucci, V. Natale, E. Carretti

We study the angular power spectra of polarized Galactic synchrotron in the range 10<l<800, at several frequencies between 0.4 and 2.7 GHz and at several Galactic latitudes up to near the North Galactic Pole. Electric- and magnetic-parity polarization spectra are found to have slopes around alpha _{E,B} = 1.4 - 1.5 in the Parkes and Effelsberg Galactic-Plane

D. Londish, S. M. Croom, B. J. Boyle, T. Shanks

We have optically identified a sample of 56 featureless continuum objects without significant proper motion from the 2dF QSO Redshift Survey (2QZ). The steep number--magnitude relation of the sample, $n(\bj) \propto 10^{0.7\bj}$, is similar to that derived for QSOs in the 2QZ and inconsistent with any population of Galactic objects. Follow up high resolution

Michael S. Sipior, Steinn Sigurdsson

Double neutron star binaries, analogous to the well known Hulse--Taylor pulsar PSR 1913+16, are guaranteed-to-exist sources of high frequency gravitational radiation detectable by LIGO. There is considerable uncertainty in the estimated rate of coalescence of such systems, with conservative estimates of ~1 per million years per galaxy, and optimistic theoret

D. Proga, T. R. Kallman, J. E. Drew, L. E. Hartley

We present synthetic line profiles as predicted by the models of 2-D line- driven disk winds due to Proga, Stone & Drew. We compare the model line profiles with HST observations of the cataclysmic variable IX Vel. The model wind consists of a slow outflow that is bounded on the polar side by a fast stream. We find that these two components of the wind produc

Piotr Popowski, Charles Alcock

We entertain the idea that robust theoretical expectations can become a tool in removing hidden observational or data-reduction biases. We illustrate this approach for a specific problem associated with gravitational microlensing. Using the fact that a group is more than just a collection of individuals, we derive formulae for correcting the distribution of

Jay Gambetta, H. M. Wiseman

Do stochastic Schrödinger equations, also known as unravelings, have a physical interpretation? In the Markovian limit, where the system {\em on average} obeys a master equation, the answer is yes. Markovian stochastic Schrödinger equations generate quantum trajectories for the system state conditioned on continuously monitoring the bath. For a given master

Christopher A. Onken, Bradley M. Peterson

Improved analysis of ultraviolet and optical monitoring data on the Seyfert 1 galaxy NGC 3783 provides evidence for the existence of a supermassive, (8.7+/-1.1)x10^6 M_sun, black hole in this galaxy. By using recalibrated spectra from the International Ultraviolet Explorer satellite and ground-based optical data, as well as refined techniques of reverberatio

D. Rusin

We investigate the properties of multiple-image gravitational lens systems formed by dark matter halos. Both the Navarro-Frenk-White (NFW) and Moore et al. mass profiles are considered, and the effects of quadrupole perturbations to the lensing potential are taken into account. The systems produced by dark halos exhibit two generic properties that serve as p

Nguyen Que Huong, Joseph L. Birman

We consider the effect of an extra electron injected into a doped quantum dot $ZnS:Mn^{2+}$. The Coulomb interaction and the exchange interaction between the extra electron and the states of the Mn ion will mix the wavefunctions, split the impurity energy levels, break the previous selection rules and change the transition probabilities. Using this model of

Finn Larsen, Jan Pieter van der Schaar, Robert G. Leigh

We interpret cosmological evolution holographically as a renormalisation group flow in a dual Euclidean field theory, as suggested by the conjectured dS/CFT correspondence. Inflation is described by perturbing around the infra-red fixed point of the dual field theory. The spectrum of the cosmic microwave background radiation is determined in terms of scaling

Rafael Hernandez, Konstadinos Sfetsos

We develop a systematic approach to G_2 holonomy manifolds with an SU(2)xSU(2) isometry using maximal eight-dimensional gauged supergravity to describe D6-branes wrapped on deformed three-spheres. A quite general metric ansatz that generalizes the celebrated Bryant-Salamon metric involves nine functions. We show that only six of them are the independent ones

Martin Schnabl

The reparametrization symmetries of Witten&#39;s vertex in ordinary or vacuum string field theories can be used to extract useful information about classical solutions of the equations of motion corresponding to D-branes. It follows, that the vacuum string field theory in general has to be regularized. For the regularization recently considered by Gaiotto et

L. P. Grishchuk

This contribution summarizes some recent work on gravitational-wave astronomy and, especially, on the generation and detection of relic gravitational waves. We begin with a brief discussion of astrophysical sources of gravitational waves that are likely to be detected first by the coming in operation laser interferometers, such as GEO, LIGO, VIRGO. Then, we

Shyamoli Chaudhuri

We present a matrix action based on the unitary group U(N) whose large N ground states are conjectured to be in precise correspondence with the weak-strong dual effective field theory limits of M theory preserving sixteen supersymmetries. We identify a finite N matrix algebra that corresponds to the spacetime and internal symmetry algebra of the Lorentz inva

J. M. Miller, A. C. Fabian, R. Wijnands, C. S. Reynolds

We observed the Galactic black hole candidate XTE J1650-500 early in its Fall, 2001 outburst with the XMM-Newton European Photon Imaging pn Camera (EPIC-pn). The observed spectrum is consistent with the source having been in the &#34;very high&#34; state. We find a broad, skewed Fe K-alpha emission line which suggests that the primary in this system may be a

Eddy Yusuf, Kun Yang

We study antiferromagnetic two-leg spin-1/2 ladders with strong bond randomness, using the real space renormalization group method. We find the low-temperature spin susceptibility of the system follows non-universal power laws, and the ground state spin-spin correlation is short-ranged. Our results suggest that there is no phase transition when the bond rand

Flavio Abdenur, Artur Avila, Jairo Bochi

We prove that non-trivial homoclinic classes of $C^r$-generic flows are topologically mixing. This implies that given $\Lambda$ a non-trivial $C^1$-robustly transitive set of a vector field $X$, there is a $C^1$-perturbation $Y$ of $X$ such that the continuation $\Lambda_Y$ of $\Lambda$ is a topologically mixing set for $Y$. In particular, robustly transitiv

Y. Yayon, M. Rappaport, V. Umansky, I. Bar-Joseph

We use low temperature near-field optical spectroscopy to image the electron density distribution in the plane of a high mobility GaAs quantum well. We find that the electrons are not randomly distributed in the plane, but rather form narrow stripes (width smaller than 150 nm) of higher electron density. The stripes are oriented along the [1-10 ] crystal dir

Christoph Lerche, Lorenz von Smekal

In the covariant description of confinement, one expects the ghost correlations to be infrared enhanced. Assuming ghost dominance, the long-range behavior of gluon and ghost correlations in Landau gauge QCD is determined by one exponent kappa. The gluon propagator is infrared finite (vanishing) for kappa =1/2 (kappa > 1/2) which is still under debate. Here,

Diego Harari, Silvia Mollerach, Esteban Roulet, Federico Sanchez

We consider the propagation of ultra high energy cosmic rays through turbulent magnetic fields and study the transition between the regimes of single and multiple images of point-like sources. The transition occurs at energies around $E_c\simeq Z~41 {\rm EeV}(B_{rms}/5 μ{\rm G}) (L/ 2 {\rm kpc})^{3/2}\sqrt{50 {\rm pc}/L_c}$, where $L$ is the distance travers

A. H. Chamseddine

Two main problems face the construction of noncommutative actions for gravity with star products: the complex metric and finding an invariant measure. The only gauge groups that could be used with star products are the unitary groups. I propose an invariant gravitational action in D=4 dimensions based on the constrained gauge group U(2,2) broken to $U(1,1)\t