January 2003 arXiv papers — page 23

H. A. Radovan, E. Behne, R. J. Zieve, J. S. Kim

We irradiate the heavy fermion superconductors (U,Th)Be_13 with high-energy heavy ions. Damage from the ions affects both heat capacity and magnetization measurements, although much less dramatically than in other superconductors. From these data and from direct imaging, we conclude that the irradiation does not create the amorphous columnar defects observed

Seth H. Cohen, Rogier A. Windhorst, Stephen C. Odewahn, Claudia A. Chiarenza

[Abridged] We present the results of the HST B-Band Parallel Survey (BBPS). It covers 0.0370 sq. deg. and consists of 31 shallow (4-6 orbit), randomly selected high latitude HST WFPC2 parallel fields with images taken in both the B (F450W) and I (F814W) filters. The goal is to morphologically classify the galaxies in a homogeneous manner and study galaxy pro

David H. Weinberg, Romeel Dav'e, Neal Katz, Juna A. Kollmeier

We review recent developments in the theory of the Lyman-alpha forest and their implications for the role of the forest as a test of cosmological models. Simulations predict a relatively tight correlation between the local Lya optical depth and the local gas or dark matter density. Statistical properties of the transmitted flux can constrain the amplitude an

Heather A. Rave, Chongshan Zhao, Heidi Jo Newberg, Brian Yanny

The Sloan Digital Sky Survey (SDSS) has scanned the entire region containing the Draco dwarf spheroidal galaxy to 23rd magnitude in g*. We present a catalog of stars found in a 453 square arcminute, elliptical region centered on the Draco dwarf spheroidal galaxy. Objects in the catalog are matched with five previously published catalogs. The catalog contains

Norbert Przybilla

Blue supergiants of spectral types B and A are the visually brightest stars in spiral and irregular galaxies, with their most luminous members (at M_V=-10) outshining entire dwarf galaxies. This characteristic allows us to use them as probes to study the Local Universe in great detail. In principle, already the existing large telescopes and instrumentation f

A. Lazarian, V. Petrosian, H. Yan, J. Cho

Understanding of the nature of gamma-ray bursts (GRBs) is one of the challenging problem facing the astrophysics community. The field of gamma ray bursts is a rapidly developing one and we expect that new missions, like SWIFT and GLAST will bring the field to a new quantitative level. The detail of the explosion, the formation of the fireball, its propagatio

Luc Binette, Pierre Ferruit, Wolfgang Steffen, Alejandro Raga

The magnitude of the temperature fluctuations (t^2) required to explain the observed inconsistencies between metallicities inferred from recombination lines and from forbidden lines cannot be attained by steady-state equilibrium photoionization models. If on the other hand the nebular ionizing source was variable, the temperature fluctuations t^2 would be si

Fabio Bresolin

Blue supergiant stars can be exceptionally bright objects in the optical, making them prime targets for the determination of extragalactic distances. I describe how their photometric and spectroscopic properties can be calibrated to provide a measurement of their luminosity. I first review two well-known techniques, the luminosity of the brightest blue super

Craig L. Sarazin

Clusters of galaxies are the largest organized structures in the Universe. They are important cosmological probes, since they are large enough to contain a fair sample of the materials in the Universe, but small enough to have achieved dynamical equilibrium. Clusters were first discovered as concentrations of hundreds of bright galaxies in a region about 3 m

Scott Dodelson, Eduardo Rozo, Albert Stebbins

Inflation produces a primordial spectrum of gravity waves in addition to the density perturbations which seed structure formation. We compute the signature of these gravity waves in the large scale shear field. In particular, the shear can be divided into a gradient mode (G or E) and a curl mode (C or B). The former is produced by both density perturbations

H. Pierre Noyes, Louis H. Kauffman, James V. Lindesay, Walter R. Lamb

By taking seriously the limits on observability which come from combining relativistic quantum mechanics with general relativity, Ed Jones has shown that the current measurements of the cosmological constant density $Ω_Λ\sim 0.7$ imply that the temperature scale at which it becomes possible to discuss cosmological models is $\sim 5 Tev$ ($5.8\times 10^{16} \

Miguel Alejandro Urbaneja, Artemio Herrero, Fabio Bresolin, Rolf-Peter Kudritzki

The spectra of two early B-type supergiant stars in the Sculptor spiral galaxy NGC 300 are analysed by means of non-LTE line blanketed unified model atmospheres, aimed at determining their chemical composition and the fundamental stellar and wind parameters. For the first time a detailed chemical abundance pattern (He, C, N, O, Mg and Si) is obtained for a B

F. Graham Smith, C. Jordan

The fourteen glitches observed during 33 years do not show the simple pattern expected from a relaxation oscillator. They may however be regarded as three major events separated by about 12 years, the third being a group of smaller glitches. There is a step increase in slowdown rate at each glitch, whose cumulative effect makes a significant contribution to

S. Vaughan, A. C. Fabian

An analysis is presented of the power spectrum of X-ray variability of the bright Seyfert 1 galaxy Mrk 766 as observed by XMM-Newton. Over the 0.2-10 keV energy range the power spectral density (PSD) is well-represented by a power-law with a slope of alpha_low ~ 1 at low frequencies, breaking to a slope of alpha_hi = 2.8 (-0.4/+0.2) at a frequency f_br ~ 5 x

F. S. Masset, J. C. B. Papaloizou

[Abridged] We evaluate the coorbital corotation torque on a migrating protoplanet. The coorbital torque is assumed to come from orbit crossing fluid elements which exchange angular momentum with the planet when they execute a U-turn at the end of horseshoe streamlines. When the planet migrates inward, the fluid elements of the inner disk undergo one such exc

N. Bissantz, A. Munk, A. Scholz

In astrophysical (inverse) regression problems it is an important task to decide whether a given parametric model describes the observational data sufficiently well or whether a non-parametric modelling becomes necessary. However, in contrast to common practice this cannot be decided by solely comparing the quality of fit due to possible over-fitting by the

Brian Warner, Patrick A. Woudt

Seventeen examples are given of Cataclysmic Variable (CV) stars possessing both Dwarf Nova Oscillations (DNOs) and Quasi-Periodic Oscillations (QPOs). These form an extension of the X-Ray Two-QPO correlation to frequencies three orders of magnitude lower. We draw attention to the existence of a second type of DNO in CVs, which is probably caused by magnetica

D. Athanasiadis, M. Kramer, I. H. Stairs, A. G. Lyne

Some of the issues concerning polarisation calibration in the context of pulsar observations are outlined along with the existing calibration system in Jodrell Bank Observatory. The principle behind the back-calibration of the Jodrell Bank database of 16 years is presented along with plans for exploiting the database in the future.

Katsura Matsumoto, Taichi Kato, Izumi Hachisu

In this paper we present and discuss our time-resolved photometry of an eclipsing recurrent nova, U Sco, during an outburst in 1999, which was conducted from immediately after the optical maximum to the final fading toward the quiescence. In the first-ever complete light-curve, a few primary and secondary eclipses of the binary system were detected, and the

F. Cancelliere, A. Comastri

We present the main results of broad band (0.1-10 keV) BeppoSAX observations of a selected sample of Narrow Line Seyfert 1 galaxies (NLS1s). We have performed a spectroscopic analysis of LECS and MECS data to test their average spectral properties, and timing analysis to study their amplitude variability. The steep average spectral indices and the high ampli

L. Page, C. Jackson, C. Barnes, C. Bennett

The primary goal of the MAP satellite, now in orbit, is to make high fidelity polarization sensitive maps of the full sky in five frequency bands between 20 and 100 GHz. From these maps we will characterize the properties of the cosmic microwave background (CMB) anisotropy and Galactic and extragalactic emission on angular scales ranging from the effective b

C. Barnes, M. Limon, L. Page, C. Bennett

We present the design, manufacturing methods, and characterization of 20 microwave feed horns currently in use on the Microwave Anisotropy Probe (MAP) satellite. The nature of the cosmic microwave background (CMB) anisotropy requires a detailed understanding of the properties of every optical component of a microwave telescope. In particular, the properties

C. L. Bennett, M. Bay, M. Halpern, G. Hinshaw

The purpose of the MAP mission is to determine the geometry, content, and evolution of the universe via a 13 arcmin full-width-half-max (FWHM) resolution full sky map of the temperature anisotropy of the cosmic microwave background radiation with uncorrelated pixel noise, minimal systematic errors, multifrequency observations, and accurate calibration. These

C. Solorzano-Inarrea, C. N. Tadhunter

Integral-field spectroscopic observations are presented for three powerful radio galaxies, namely 3C277.3 (Coma A; z=0.0857), 3C171 (z=0.2384) and 3C265 (z=0.811), which are known to be undergoing jet-cloud interactions. The morphology, kinematics and ionization of the gas in the emission-line structure of these sources are mapped and analysed. One-dimension

Kimball Martin

Let K/F be an arbitrary Galois extension of number fields and r be a representation of Gal(K/F) into GSp(4,C). Let E_16 be the elemetary abelian group of order 16 and C_5 the cyclic group of order 5. If the image of r in the projective space PGSp(4,C) is isomorphic to the semidirect product of E_16 by C_5, then we show r satisfies Artin's conjecture by p

R. Di Stefano, A. K. H. Kong

We use a set of conservative criteria to identify luminous supersoft X-ray sources(SSSs) in external galaxies. We test this approach on blackbody models, and then apply it to {\it Chandra} data from 4 galaxies: an elliptical (NGC 4967), 2 face-on spirals (M101 and M83), and an interacting galaxy (M51). We find SSSs in every galaxy, and estimate that the tota

Kaya Mori, Charles J. Hailey

We present a comprehensive investigation of the two broad absorption features observed in the X-ray spectrum of the neutron star 1E1207.4-5209 based on a recent analysis of the 260 ksec XMM-Newton data by Mori et al. 2005. Expanding on our earlier work (Hailey & Mori 2002) we have examined all previously proposed atmospheric models for 1E1207.4-5209. Using o

David Nadler

We present a version of the Matsuki correspondence for the affine Grassmannian $Gr=G(C((t)))/G(C[[t]])$ of a connected reductive complex algebraic group $G$. The main statement is an anti-isomorphism between the orbit posets of two subgroups of $G(C((t)))$ acting on $Gr$. The first is the polynomial loop group $LG_R$ of a real form $G_R$ of $G$; the second i

G. Arutyunov, E. Sokatchev

We study the four-point correlator of 1/2-BPS operators of weight 4 in N=4 SYM, which are dual to massive KK modes in AdS_5 supergravity. General field-theoretic arguments lead to a partially non-renormalized form of the amplitude that depends on two a priori independent functions of the conformal cross-ratios. We explicitly compute the amplitude in the larg

H. A. Fertig, Joseph P. Straley

The zero-bias tunneling resonance in quantum Hall bilayer systems is investigated via numerical simulations of the classical two dimensional XY model with a symmetry-breaking field. Disorder is included in the model, and is shown to nucleate strings of overturned spins proliferated through the system, with unpaired vortices and antivortices at their endpoint

S. Pakvasa, J. W. F. Valle

We review neutrino oscillation physics, including the determination of mass splittings and mixings from current solar, atmospheric, reactor and accelerator neutrino data. A brief discussion is given of cosmological and astrophysical implications. Non-oscillation phenomena such as neutrinoless double beta decay would, if discovered, probe the absolute scale o

D. V. Khveshchenko

We study the problem of environmentally-induced decoherence in a near-critical one-dimensional system of N>>1 coupled qubits. Using the Jordan-Wigner fermion representation of the qubit operators we identify the decoherence rates relevant for the two-qubit reduced density matrix. We find that a desirable onset of massive shared entanglement in the near-criti

Lizardo H. C. M. Nunes, M. S. Figueira, E. V. L. de Mello

We use the X-boson method to study the heavy fermion superconductivity employing an extension of the periodic Anderson model in the $ U = \infty $ limit with a nearest neighbor attractive interaction between the localized $ f $-electrons and we show that higher values of the hybridization parameter implies in lower values associated to the maximum of the sup

D. Alonso, F. Sammarruca

A microscopic calculation of the equation of state for asymmetric nuclear matter is presented. We employ realistic nucleon-nucleon forces and operate within the Dirac-Brueckner-Hartree-Fock approach to nuclear matter. The focal point of this paper is a (momentum-space) G-matrix which properly accounts for the asymmetry between protons and neutrons. This will

Monika Grothe

Mixing in the D0 system may provide a sensitive probe for new physics beyond the Standard Model (SM) but has so far eluded experimental observation. The SM predictions are typically small (< 10^{-3}) for the mixing parameters x, y which, in the absence of charge-parity (CP) symmetry violation, measure the mass (x= Delta(m)/Gamma) and lifetime (y= Delta(Gamma

Haiyan Gao

Nucleon electromagnetic form factors are fundamental quantities related to the charge and magnetization distributions inside the nucleon. Understanding the nucleon electromagnetic structure in terms of the underlying quark and gluon degrees of freedom of quantum chromodynamics is a challenging and urgent task. The nucleon electromagnetic form factors have be

Peter A. Storm

Bonahon conjectured that compact convex cores with totally geodesic boundary uniquely minimize volume over all hyperbolic 3-manifolds in the same homotopy class. This paper proves Bonahon&#39;s conjecture. The proofs extend the techniques of Besson-Courtois-Gallot.

R. Fossion, K. Heyde, G. Thiamova, P. Van Isacker

A three-configuration mixing calculation is performed in the context of the interacting boson model with the aim to describe recently observed collective bands built on low-lying $0^+$ states in neutron-deficient lead isotopes. The configurations that are included correspond to the regular, spherical states as well as two-particle two-hole and four-particle

HERMES Collaboration, A. Airapetian, N. Akopov, M. Amarian

This paper describes the use of the time-of-flight (TOF) technique as a particle identification method for the HERMES experiment. The time-of-flight is measured by two 1x4 m^2 scintillation hodoscopes that initially were designed for the first-level trigger only. However, the suitable time structure of the HERA electron beam allows an extension of their func

Stefania De Curtis, Daniele Dominici, Jose R. Pelaez

We show how the tree level unitarity violations of compactified extra dimensional extensions of the Standard Model become much stronger when the scalar sector is included in the bulk. This effect occurs when the couplings are not suppressed for larger Kaluza-Klein levels, and could have relevant consequences for the phenomenology of the next generation of co

Boaz Tsaban

According to a result of Kocinac and Scheepers, the Hurewicz covering property is equivalent to a somewhat simpler selection property: For each sequence of large open covers of the space one can choose finitely many elements from each cover to obtain a groupable cover of the space. We simplify the characterization further by omitting the need to consider seq

L. Bégin, J. -F. Fortin, P. Jacob, P. Mathieu

Fermionic-type character formulae are presented for charged irreduciblemodules of the graded parafermionic conformal field theory associated to the coset $osp(1,2)_k/u(1)$. This is obtained by counting the weakly ordered `partitions&#39; subject to the graded $Z_k$ exclusion principle. The bosonic form of the characters is also presented.

Ran Levi, Bob Oliver

A p-local finite group is an algebraic structure with a classifying space which has many of the properties of p-completed classifying spaces of finite groups. In this paper, we construct a family of 2-local finite groups, which are exotic in the following sense: they are based on certain fusion systems over the Sylow 2-subgroup of Spin_7(q) (q an odd prime p

J. Lukierski, V. D. Lyakhovsky, M. Mozrzymas

We describe the classical $o(3,2)$ $r$-matrices as generating the quantum deformations of either D=3 conformal algebra with mass-like deformation parameters or D=4 $AdS$ algebra with dimensionless deformation parameters. We describe the quantization of classical $o(3,2)$ $r$-matrices via Drinfeld twist method which locates the deformation in the coalgebra se

Yusuke Kimura

Matrix descriptions of higher dimensional spherical branes are investigated. It is known that a fuzzy 2k-sphere is described by the coset space SO(2k+1)/U(k) and has some extra dimensions. It is shown that a fuzzy 2k-sphere is comprised of n^{\frac{k(k-1)}{2}} spherical D(2k-1)-branes and has a fuzzy 2(k-1)-sphere at each point. We can understand the relatio

V. E. Didenko, M. A. Vasiliev

Pure gauge representation for general vacuum background fields (Cartan forms) in the generalized $AdS$ superspace identified with $OSp(L,M)$ is found. This allows us to formulate dynamics of free massless fields in the generalized $AdS$ space-time and to find their (generalized) conformal and higher spin field transformation laws. Generic solution of the fie

Andreas Ipp, Guy D. Moore, Anton Rebhan

We repeat and correct the recent calculation of the thermodynamic potential of hot QCD in the limit of large number N_f of fermions. The new result for the thermal pressure turns out to agree significantly better with results obtained from perturbation theory at small coupling. For large coupling, a nonmonotonic behaviour is reproduced, but the pressure of t

Y. Tsori, F. Tournilhac, L. Leibler

We consider orientation mechanisms for block copolymers in an electric field. Theoretical and experimental studies have shown that nonuniformity of the dielectric constant gives rise to a preferred orientation of the melt with respect to the applied field. We show that the presence of ions, as found in anionically prepared copolymers, may increase the alignm

Yusuf Dincer, L. M. Sehgal

We investigate the double Dalitz decays $B_s \to l^+ l^- l&#39;^+ l&#39;^-$ on the basis of the effective Hamiltonian for the transition $b \bar{s} \to l^+ l^-$, and universal form factors suggested by QCD. The correlated mass spectrum of the two lepton pairs in the decay $B_s \to e^+ e^- μ^+ μ^-$ is derived in an efficient way, using a QED result for meson

Junegone Chay, Chul Kim

We show that the amplitudes for B decays into two light mesons at leading order in soft-collinear effective theory are factorized to all orders in alpha_s. We construct gauge-invariant four-quark operators by employing the effective theories SCET_I for sqrt{m_b Λ} <μ<m_b, and SCET_II for μ<sqrt{m_b Λ} with Lambda ~0.5 GeV. These operators do not allow gluon

Jianhui He, Shiping Feng, Wei Yeu Chen

The dynamical spin response of doped two-leg ladder antiferromagnets is investigated based on the fermion-spin approach. Our calculations clearly demonstrate a crossover from the incommensurate antiferromagnetism in the weak interchain coupling regime to commensurate spin fluctuation in the strong interchain coupling regime. In particular, the nuclear spin-l

Toshihiro Kubo, Arisato Kawabata

We investigate effects of electron-electron interaction on the transmission probability of electrons through a tunnel junction in a strong magnetic field. We start with the Hartree-Fock approximation, and we show that the coulomb interaction, which gives rise to the divergence of Fock correction, should be replaced by the dynamically screened interaction. We

Sourendu Gupta

The electrical conductivity in the hot phase of the QCD plasma is extracted from a quenched lattice measurement of the Euclidean time vector correlator for 1.5 < T/T_c < 3. The spectral density in the vicinity of the origin is examined using a method specially adapted to this region, and a peak at small energies is seen. The continuum limit of the electrical

J. Raufeisen

Transverse momentum broadening of fast partons propagating through a large nucleus is proportional to the average color field strength in the nucleus. In this work, the corresponding coefficient is determined in three different frameworks, namely in the color dipole approach, in the approach of Baier et al. and in the higher twist factorization formalism. Th

Clifford M. Will

We calculate the delay in the propagation of a light signal past a massive body that moves with speed v, under the assumption that the speed of propagation of the gravitational interaction c_g differs from that of light. Using the post-Newtonian approximation, we consider an expansion in powers of v/c beyond the leading ``Shapiro&#39;&#39; time delay effect,

Dorit Aharonov

Recently Shi proved that Toffoli and Hadamard are universal for quantum computation. This is perhaps the simplest universal set of gates that one can hope for, conceptually; It shows that one only needs to add the Hadamard gate to make a &#39;classical&#39; set of gates quantum universal. In this note we give a few lines proof of this fact relying on Kitaev&

G. Giedke, J. Eisert, J. I. Cirac, M. B. Plenio

We present a theory of entanglement transformations of Gaussian pure states with local Gaussian operations and classical communication. This is the experimentally accessible set of operations that can be realized with optical elements such as beam splitters, phase shifts and squeezers, together with homodyne measurements. We provide a simple necessary and su

A. Carollo, I. Fuentes-Guridi, M. Franca Santos, V. Vedral

We calculate the geometric phase associated to the evolution of a system subjected to decoherence through a quantum-jump approach. The method is general and can be applied to many different physical systems. As examples, two main source of decoherence are considered: dephasing and spontaneous decay. We show that the geometric phase is completely insensitive

Janus Wesenberg, Klaus Moelmer

We present a composite pulse controlled phase gate which together with a bus architecture improves the feasibility of a recent quantum computing proposal based on rare-earth-ion doped crystals. Our proposed gate operation is tolerant to variations between ions of coupling strengths, pulse lengths, and frequency shifts, and it achieves worst case fidelities a

V. B. Svetovoy, M. V. Lokhanin

Temperature correction to the Casimir force is considered for real metals at low temperatures. With the temperature decrease the mean free path for electrons becomes larger than the field penetration depth. In this condition description of metals with the impedance of anomalous skin effect is shown to be more appropriate than with the permittivity. The effec

Johan Jersblad, Harald Ellmann, Laurent Sanchez-Palencia, Anders Kastberg

We present a direct measurement of velocity distributions in two dimensions by using an absorption imaging technique in a 3D near resonant optical lattice. The results show a clear difference in the velocity distributions for the different directions. The experimental results are compared with a numerical 3D semi-classical Monte-Carlo simulation. The numeric

Daniel A. Lidar, K. Birgitta Whaley

Decoherence is the phenomenon of non-unitary dynamics that arises as a consequence of coupling between a system and its environment. It has important harmful implications for quantum information processing, and various solutions to the problem have been proposed. Here we provide a detailed a review of the theory of decoherence-free subspaces and subsystems,

Apoorva Patel

Competition for available resources is natural amongst coexisting species, and the fittest contenders dominate over the rest in evolution. The dynamics of this selection is studied using a simple linear model. It has similarities to features of quantum computation, in particular conservation laws leading to destructive interference. Compared to an altruistic

R. J. Magyar, W. Terilla, K. Burke

The adiabatic connection curve of density functional theory (DFT) is accurately calculated beyond the physical interaction strength for Hooke&#39;s atom, two interacting electrons in a harmonic well potential. Extrapolation of the accurate curve to the infinite coupling limit agrees well with the strictly correlated electron (SCE) hypothesis but the approach

B. G. Sidharth

It is argued that a noncommutative geometry of spacetime leads to a reconciliation of electromagnetism and gravitation while providing an underpinning to Weyl&#39;s geometry. It also leads to a cosmology consistent with observation. A few other ramifications are also examined.

Blaise Aguera y Arcas, Adrienne Fairhall

The computation performed by a neuron can be formulated as a combination of dimensional reduction in stimulus space and the nonlinearity inherent in a spiking output. White noise stimulus and reverse correlation (the spike-triggered average and spike-triggered covariance) are often used in experimental neuroscience to `ask&#39; neurons which dimensions in st

M. R. Mahdavi

In this note we will first argue that there is evidence in supporting the view that de Broglie waves have a gravitational origin. In view of the extreme weakness of the gravitational field, however, this seems to be an unlikely proposition. We consider the problem of the atom in the light of a proposed electron theory [physics/0212013] and show that in this

Angela Bonaccorso

In this talk I discuss two types of experiments with exotic nuclei which could be performed at the forthcoming Italian INFN facilities with radioactive beams. First I will discuss nuclear and Coulomb breakup experiments which involve heavy exotic beams and intermediate incident energies, thus being suited for the LNL-SPES proposed facility. Then I will discu

Angela Bonaccorso

This talk examines a number of reaction mechanisms for scattering initiated by an exotic projectile. Comparisons are made with recent experimental data, in order to extract information on the peculiarity of the nuclear structure under extreme conditions and to test the accuracy of the available theoretical methods. Predictions for future experiments are also

M. V. Zverev, J. W. Clark, V. A. Khodel

The $^3P_2$-$^3F_2$ pairing model is generally considered to provide an adequate description of the superfluid states of neutron matter at densities some 2-3 times that of saturated symmetrical nuclear matter. The problem of solving the system of BCS gap equations expressing the $^3P_2$-$^3F_2$ model is attacked with the aid of the separation approach. This

Ning Wang, Xizhen Wu, Zhuxia Li

By using the updated improved Quantum Molecular Dynamics model in which a surface-symmetry potential term has been introduced for the first time, the excitation functions for fusion reactions of $^{40,48}$Ca+$^{90,96}$Zr at energies around the Coulomb barrier have been studied. The experimental data of the fusion cross sections for $^{40}$Ca+$^{90,96}$Zr hav

Munetake Hasegawa, Kazunari Kaneko

Effects of resonant single-particle (s.p.) states on the pairing correlations are investigated by an exact treatment of the pairing Hamiltonian on the Gamow shell model basis. We introduce the s.p. states with complex energies into the Richardson equations. The solution shows the property that the resonant s.p. states with large widths are less occupied. The

Anatoly G. Nikitin, Roman O. Popovych

The authors suggest a new powerful tool for solving group classification problems, that is applied to obtaining the complete group classification in the class of nonlinear Schrödinger equations of the form $iψ_t+Δψ+F(ψ,ψ^*)=0$.

Bogdan Alexandrov, Stefan Ivanov

We prove the vanishing of the first Betti number on compact manifolds admitting a Weyl structure whose Ricci tensor satisfies certain positivity conditions, thus obtaining a Bochner-type vanishing theorem in Weyl geometry. We also study compact Hermitian-Weyl manifolds with non-negative symmetric part of the Ricci tensor of the canonical Weyl connection and

Bogdan Alexandrov, Stefan Ivanov

We prove the vanishing of the Dolbeault cohomology groups on Hermitian manifolds with $dd^c$-harmonic Kähler form and positive (1,1)-part of the Ricci form of the Bismut connection. This implies the vanishing of the Dolbeault cohomology groups on complex surfaces which admit a conformal class of Hermitian metrics, such that the Ricci tensor of the canonical

A. Rod Gover, C. Robin Graham

CR invariant differential operators on densities with leading part a power of the sub-Laplacian are derived. One family of such operators is constructed from the ``conformally invariant powers of the Laplacian&#39;&#39; via the Fefferman metric; the powers which arise for these operators are bounded in terms of the dimension. A second family is derived from

Zoran Skoda

Viewing comodule algebras as the noncommutative analogues of affine varieties with affine group actions, we propose rudiments of a localization approach to nonaffine Hopf algebraic quotients of noncommutative affine varieties corresponding to comodule algebras. After reviewing basic background on noncommutative localizations, we introduce localizations compa

Laurent Buse, Andre Galligo

Given two curves in $\PP^3$, either implicitly or by a parameterization, we want to check if they intersect. For that purpose, we present and further develop generalized resultant techniques. Our aim is to provide a closed formula in the inputs which vanishes if and only if the two curves intersect. This could be useful in Computer Aided Design, for computin

P. Tumarkin

A Kac-Moody algebra is called hyperbolic if it corresponds to a generalized Cartan matrix of hyperbolic type. We study root subsystems of root systems of hyperbolic algebras. In this paper, we classify maximal rank regular hyperbolic subalgebras of hyperbolic Kac-Moody algebras.

Matthias Franz

Let T be a torus. We show that Koszul duality can be used to compute the equivariant cohomology of topological T-spaces as well as the cohomology of pull backs of the universal T-bundle. The new features are that no further assumptions about the spaces are made and that the coefficient ring may be arbitrary. This gives in particular a Cartan-type model for t

Ciro Ciliberto, Mikhail Zaidenberg

We construct new examples of Kobayashi hyperbolic hypersurfaces in the projective 4-space. They are generic projections of the triple symmetric product of a generic curve of genus at least 7, smoothly embedded in the projective 7-space.

U. Bunke, J. Park

In this note we specialize and illustrate the ideas developed in the paper math.DG/0201112 of the first author (&#34;Index theory, eta forms, and Deligne cohomology &#34;) in the case of the determinant line bundle. We discuss the surgery formula in the adiabatic limit using the adiabatic decomposition formula of the zeta regularized determinant of the Dirac

Leroux Philippe

We construct from coassociative coalgebras, bialgebras, Hopf algebras, new objects such as Poisson algebras, Leibniz algebras defined by J-L Loday and M. Ronco and explore the notion of coassociative manifolds.

John R. Klein, John Rognes

We formulate and prove a chain rule for the derivative, in the sense of Goodwillie, of compositions of weak homotopy functors from simplicial sets to simplicial sets. The derivative spectrum dF(X) of such a functor F at a simplicial set X can be equipped with a right action by the loop group of its domain X, and a free left action by the loop group of its co

Csaba Schneider

For odd primes we prove some structure theorems for finite $p$-groups $G$, such that $G&#39;&#39;\neq 1$ and $|G&#39;/G&#39;&#39;|=p^3$. Building on results of Blackburn and Hall, it is shown that $\lcs G3$ is a maximal subgroup of $G&#39;$, the group $G$ has a central decomposition into two simpler subgroups, and, moreover, $G&#39;$ has one of two isomorphi

A. M. Savchuk, A. A. Shkalikov

In this paper we propose four different methods to determine Sturm-Liouville operator on an interval $(a,b)$ in case, when a potential $q(x)$ is a distribution from the Sobolev space with negative index of smoothness, i.e. (q\in W_2^{-θ}), where (θ\le 1). The main and second terms of asymptotic series for eigenvalues and eigenfunctions of these operators are

Volker Kaibel, Raphael Mechtel, Micha Sharir, Günter M. Ziegler

The worst-case expected length f(n) of the path taken by the simplex algorithm with the Random Edge pivot rule on a 3-dimensional linear program with n constraints is shown to be bounded by 1.3445 n <= f(n) <= 1.4943 n for large enough n.

Jose A. Galvez, Pablo Mira

We produce a new general family of flat tori in R^4, the first one since Bianchi&#39;s classical works in the 19th century. To construct these flat tori, obtained via small perturbation of certain Hopf tori in S^3, we first present a global description of all isometric immersions of R^2 into R^4 with flat normal bundle.

S. M. Gusein-Zade, I. Luengo, A. Melle-Hernandez

Let $\cal R$ be either the Grothendieck semiring (semiring with multiplication) of complex algebraic varieties, or the Grothendieck ring of these varieties, or the Grothendieck ring localized by the class of the complex affine line. We introduce a construction which defines operations of taking powers of series over these (semi)rings. This means that, for a

Sebastian Goette

We compare the higher analytic torsion of Bismut and Lott of a fibre bundle p: M -> B equipped with a flat vector bundle F -> M and a fibre-wise Morse function h on M with a higher torsion T that is constructed in terms of a families Thom-Smale complex associated to h and F, thereby extending previous joint work with Bismut. Under additional conditions on F,

B. Geyer, D. M. Gitman, P. M. Lavrov, P. Yu. Moshin

We consider the two-dimensional model of W3-gravity within Lagrangian quantization methods for general gauge theories. We use the Batalin-Vilkovisky formalism to study the arbitrariness in the realization of the gauge algebra. We obtain a one-parametric non-analytic extension of the gauge algebra, and a corresponding solution of the classical master equation

Antonio S. de Castro, Wiliam G. Pereira

The problem of confinement of neutral fermions in two-dimensional space-time is approached with a pseudoscalar double-step potential in the Dirac equation. Bound-state solutions are obtained when the coupling is of sufficient intensity. The confinement is made plausible by arguments based on effective mass and anomalous magnetic interaction.

László Á. Gergely

We review and compare different variational formulations for the Schrödinger field. Some of them rely on the addition of a conveniently chosen total time derivative to the hermitic Lagrangian. Alternatively, the Dirac-Bergmann algorithm yields the Schrödinger equation first as a consistency condition in the full phase space, second as canonical equation in t

Joseph Ambrose G. Pagaran

An algorithm is devised to generate characteristic identities between Maxwell fieldstrength invariants (traced over Lorentz indices and disregarding ordering) that suffer linear dependence in certain dimensionalities as they have been originally obtained using a Maple routine. These relations between invariants are then applied to simplify the Abelian Born-I

Sven Heinemeyer, Georg Weiglein

The current status of the theoretical predictions for the electroweak precision observables M_W, sin^2_theta_eff and m_h within the MSSM is briefly reviewed. The impact of recent electroweak two-loop results to the quantity Delta_rho is analysed and the sensitivity of the electroweak precision observables to the top-quark Yukawa coupling is investigated. Fur

John F. Beacom, Sergio Palomares-Ruiz

Recent results show that atmospheric $ν_μ$ oscillate with $δm^2 \simeq 3 \times 10^{-3}$ eV$^2$ and $\sin^2{2θ_{atm}} \simeq 1$, and that conversion into $ν_e$ is strongly disfavored. The Super-Kamiokande (SK) collaboration, using a combination of three techniques, reports that their data favor $ν_μ\to ν_τ$ over $ν_μ\to ν_{sterile}$. This distinction is extr

N. Beisert, B. Borasoy

The hadronic decays eta -> pi pi pi, eta-prime -> pi pi pi and eta-prime -> eta pi pi are investigated within a U(3) chiral unitary approach. Final state interactions are included by deriving the effective s-wave potentials for meson meson scattering from the chiral effective Lagrangian and iterating them in a Bethe-Salpeter equation. With only a small set o

A. Papa

The self-consistency of the assumption of Reggeized form of the production amplitudes in multi-Regge kinematics, which are used in the derivation of the BFKL equation, leads to strong bootstrap conditions. The fulfillment of these conditions opens the way to a rigorous proof of the BFKL equation in the next-to-leading approximation. The strong bootstrap cond

Jen-Chieh Peng

The recent progress on our understanding of the flavor structure of unpolarized and polarized nucleon sea is reviewed. The large flavor asymmetry between the up and down sea quark distributions is now well established. This asymmetry strongly suggests the importance of the mesonic degrees of freedom in the description of the nucleon sea. The strong connectio

Kurt Langfeld

The standard Faddeev Popov gauge fixing procedure is put on solid grounds by taking into account a topological factor which corrects for the number of Gribov copies within the first Gribov horizon. Zwanziger&#39;s stochastic approach to gauge fixed Yang-Mills theory is briefly reviewed. A simple toy model is presented which illustrates both methods. Within t