June 2002 arXiv papers — page 3

N. Karchev

The present paper discusses magnon-mediated superconductivity in ferromagnetic metals. The mechanism explains in a natural way the fact that the superconductivity in UGe_2, ZrZn_2 and URhGe is apparently confined to the ferromagnetic phase.The order parameter is a spin anti-parallel component ofa spin-1 triplet with zero spin projection. The transverse spinf

Hiroshi Nagaoka, Masahito Hayashi

The information-spectrum analysis made by Han for classical hypothesis testing for simple hypotheses is extended to a unifying framework including both classical and quantum hypothesis testing as well as fixed-length source coding, whereby general formulas for several quantities concerning the asymptotic optimality of tests/codes are established in terms of

Masahito Hayashi, Hiroshi Nagaoka

The capacity of a classical-quantum channel (or in other words the classical capacity of a quantum channel) is considered in the most general setting, where no structural assumptions such as the stationary memoryless property are made on a channel. A capacity formula as well as a characterization of the strong converse property is given just in parallel with

Shigeki Onoda, Masatoshi Imada

The 2D half-filled Hubbard model is studied by a nonperturbative analytic theory of correlator projection. The original dynamical mean-field approximation (DMFA) is reproduced at the first-order projection and then improved by systematic inclusion of spatial correlations at higher orders. A geometrical frustration induces a first-order Mott transition surfac

K. W. Mahmud, J. N. Kutz, W. P. Reinhardt

We present a representative set of analytic stationary state solutions of the Nonlinear Schrödinger equation for a symmetric double square well potential for both attractive and repulsive nonlinearity. In addition to the usual symmetry preserving even and odd states, nonlinearity introduces quite exotic symmetry breaking solutions - among them are trains of

M. Barkovich, J. C. D'Olivo, R. Montemayor, J. F. Zanella

Anisotropic neutrino emission during the neutron star formation can be the origin of the observed proper motions of pulsars. We derive a general expression for the momentum asymmetry in terms of the neutrino energy flux gradient, and show that a nonvanishing effect is induced at the lowest order by a deformed neutrinosphere. In particular, this result is val

J. Bao, A. V. Bragas, J. K. Furdyna, R. Merlin

We use ultrafast optical pulses and coherent techniques to create spin entangled states of non-interacting electrons bound to donors (at least three) and at least two Mn2+ ions in a CdTe quantum well. Our method, relying on the exchange interaction between localized excitons and paramagnetic impurities, can in principle be applied to entangle a large number

C . S. Unnikrishnan

I have been arguing that quantum nonlocality, deeply entrenched in the present formalism of quantum mechanics and widely believed as a reality by physicists, is in fact absent. Spooky nonlocal state reduction is the most, and perhaps the only irrational feature of present day physics. There are experimental results that reject nonlocal state reduction at a d

Sigmund Kohler, Peter Hänggi

We study dissipative tunneling in a double well potential that is driven close to a resonance between the lowest tunnel doublet and a singlet. While the coherent dynamics can be described well within a three-level approximation, dissipative transitions to levels outside the singlet and the doublet may play a crucial role. Moreover, such transitions can enhan

Subhash Kak

Error correction, in the standard meaning of the term, implies the ability to correct all small analog errors and some large errors. Examining assumptions at the basis of the recently proposed quantum error-correcting codes, it is pointed out that these codes can correct only a subset of errors, and are unable to correct small phase errors which can have dis

Cornelis Storm, Philip Nelson

Single molecule experiments on single- and double stranded DNA have sparked a renewed interest in the force-extension of polymers. The extensible Freely Jointed Chain (FJC) model is frequently invoked to explain the observed behavior of single-stranded DNA. We demonstrate that this model does not satisfactorily describe recent high-force stretching data. We

E. Pavarini, L. C. Andreani

The photonic band dispersion and density of states (DOS) are calculated for the three-dimensional (3D) hexagonal structure corresponding to a distributed Bragg reflector patterned with a 2D triangular lattice of circular holes. Results for the Si/SiO$_2$ and GaAs/AlGaAs systems determine the optimal parameters for which a gap in the 2D plane occurs and overl

Avinash Singh

A pedagogically instructive experimental procedure is suggested for distinguishing between different damping terms in a weakly damped oscillator, which highclights the connection between non-linear damping and initial-amplitude dependence. The most common damping terms such as contact friction, air resistance, viscous drag, and electromagnetic damping have v

Mohamed El Djalil Kadi-Hanifi

Nous avons analyse les distributions angulaires de la diffusion elastique pour differents systemes a des energies proches de la barriere de Coulomb au moyen d'un potentiel semi phenomenologique. Les distributions radiales calculees au moyen de ces potentiels montrent sans ambiguite qu'aux energies proches de la barriere de Coulomb, l'absorption s

S. Hilaire, J. -F. Berger, M. Girod, W. Satula

Large scale Hartree-Fock-Bogoliubov (HFB) calculations with the finite-range Gogny force D1S have been performed in order to extract the corresponding theoretical average mass dependence of the nuclear gap values. Good agreement with experimental data from the three-point filter $Δ^{(3)}$(N) with N odd has been found for both the neutron and proton gaps. The

M. Rousseau, C. Beck, C. Bhattacharya, V. Rauch

The possible occurrence of highly deformed configurations in the $^{40}$Ca di-nuclear system formed in the $^{28}$Si + $^{12}$C reaction is investigated by analyzing the spectra of emitted light charged particles. Both inclusive and exclusive measurements of the heavy fragments (A $\geq$ 10) and their associated light charged particles (protons and $α$ parti

Victor Yakhot

Generation of the large-scale coherent vortical structurs in homogeneous shear flow couples dynamical processes of energy and enstrophy production. In the large rate of strain limit, the simple estimates of the contributions to the energy and enstrophy equations result in a dynamical system, describing experimentally and numerically observed self-sustained n

A Karasu, S Yu Sakovich, I Yurdusen

The integrability of a coupled KdV-mKdV system is tested by means of singularity analysis. The true Lax pair associated with this system is obtained by the use of prolongation technique.

J. Dittrich, P. Duclos

The classical scalar massive field satisfying the Klein-Gordon equation in a finite one-dimensional space interval of periodically varying length with Dirichlet boundary conditions is studied. For the sufficiently small mass, the energy can exponentially grow with time under the same conditions as for the massless case. The proofs are based on estimates of e

Simon Gravel, Pavel Winternitz

We consider here the coexistence of first- and third-order integrals of motion in two dimensional classical and quantum mechanics. We find explicitly all potentials that admit such integrals, and all their integrals. Quantum superintegrable systems are found that have no classical analog, i.e. the potentials are proportional to \hbar^2, so their classical li

Frederick M. Goodman, Hans Wenzl

We prove the following result: For a generic value of the parameter, the Temperley-Lieb category has no non-zero, proper tensor ideal. When the parameter $d$ is equal to $2\cos(π/n)$ for some $n \ge 3$, then the Temperley-Lieb category has exactly one non-zero, proper ideal, namely the ideal of negligible morphisms.

Lennard F. Bakker

The multiplier representation of the generalized symmetry group of a quasiperiodic flow on the n-torus defines, for each subgroup of the multiplier group of the flow, a group invariant of the smooth conjugacy class of that flow. This group invariant is the internal semidirect product of a subgroup isomorphic to the n-torus by a subgroup isomorphic to that su

Marco Lenci

We prove that any generic (i.e., possibly aperiodic) Lorenz gas in two dimensions, with finite horizon and non-degenerate geometrical features, is ergodic if it is recurrent. We also give examples of aperiodic recurrent gases.

Vladimir Petrov Kostov

The Deligne-Simpson problem (DSP) (resp. the weak DSP) is formulated like this: {\em give necessary and sufficient conditions for the choice of the conjugacy classes $C_j\subset GL(n,{\bf C})$ or $c_j\subset gl(n,{\bf C})$ so that there exist irreducible (resp. with trivial centralizer) $(p+1)$-tuples of matrices $M_j\in C_j$ or $A_j\in c_j$ satisfying the e

Alexei Bondal, Dmitri Orlov

We show how derived categories build bridges across the current mathematical mainstream, linking geometric and algebraic, commutative and noncommutative, local and global banks. Arches in these bridges are pieces of semiorthogonal decompositions of triangulated categories. To appear in the Proceedings of the ICM 2002 in Beijing.

K. Styrkas, V. Tarasov, A. Varchenko

We study the meromorphic family of intertwining operators between Verma modules and their products with finite-dimensional ones. A regularizing operator, acting in a finite dimensional module U, makes this family holomorphic, and conjugates the dynamical Weyl group operators to constant operators. We prove uniqueness property for regularizing operators, and

Tsz Ho Chan

In this paper, we derive a more precise version of the Strong Pair Correlation Conjecture on the zeros of the Riemann zeta function under Riemann Hypothesis and Twin Prime Conjecture.

Tsz Ho Chan

Goldston and Montgomery [3] proved that the Strong Pair Correlation Conjecture and two second moments of primes in short intervals are equivalent to each other under Riemann Hypothesis. In this paper, we get the second main terms for each of the above and show that they are almost equivalent to each other.

Boris Okun

We construct series of examples of exotic smooth structures on compact locally symmetric spaces of noncompact type. In particular, we obtain higher rank examples, which do not support Riemannian metric of nonpositive curvature. The examples are obtained by taking the connected sum with an exotic sphere. To detect the change of the smooth structure we use a t

C. P. Hughes, Z. Rudnick

We consider the scaling limit of linear statistics for eigenphases of a matrix taken from one of the classical compact groups. We compute their moments and find that the first few moments are Gaussian, whereas the limiting distribution is not. The precise number of Gaussian moments depends upon the particular statistic considered.

Peter Ebenfelt, Bernhard Lamel

We prove finite jet determination results for smooth CR embeddings which are of constant degeneracy, using the method of complete systems. As an application, we derive a reflection principle for mappings between a Levi-nondegenerate hypersurface in C^N and a Levi-nondegenerate hypersurface in C^{N+1}. We also give an independent proof of the reflection princ

Joel Hass, Paul Norbury, J. Hyam Rubinstein

We construct a smooth Riemannian metric on any 3-manifold with the property that there are genus zero embedded minimal surfaces of arbitrarily high Morse index.

Alexander Karabegov

We give a simple formula for the operator C_3 of the standard deformation quantization with separation of variables on a Kähler manifold M. Unlike C_1 and C_2, this operator can not be expressed in terms of the Kähler-Poisson tensor on M. We modify C_3 to obtain a covariant deformation quantization with separation of variables up to the third order which is

Daniel S. Freed

Twisted K-theory has received much attention recently in both mathematics and physics. We describe some models of twisted K-theory, both topological and geometric. Then we state a theorem which relates representations of loop groups to twisted equivariant K-theory. This is joint work with Michael Hopkins and Constantin Teleman.

Vadim Kostrykin, Konstantin A. Makarov, Alexander K. Motovilov

We discuss the problem of perturbation of spectral subspaces for linear self-adjoint operators on a separable Hilbert space. Let $A$ and $V$ be bounded self-adjoint operators. Assume that the spectrum of $A$ consists of two disjoint parts $σ$ and $Σ$ such that $d=\text{dist}(σ, Σ)>0$. We show that the norm of the difference of the spectral projections $\EE_A

Bhupinder Singh Anand

Goedel's explicit thesis was that his undecidable formula GUS is a well-formed, well-defined formal sentence in any formalisation of Intuitive Arithmetic IA in which the axioms and rules of inference are recursively definable. His implicit thesis was that GUS is not formally inconsistent in any such system. I argue in a constructive, intuitionistically u

Mary K. Gaillard, Joel Giedt

We consider the case of several scalar fields, charged under a number of U(1) factors, acquiring vacuum expectation values due to an anomalous U(1). We demonstrate how to make redefinitions at the superfield level in order to account for tree-level exchange of vector supermultiplets in the effective supergravity theory of the light fields in the supersymmetr

Igor O. Cherednikov

The simple consequences of the renormalization group invariance in calculations of the ground state energy for models of confined quantum fields are discussed. The case of (1+1)D MIT quark bag model is considered in detail.

Jacques Distler, Hans Jockers, Hyukjae Park

An important subclass of D-branes on a Calabi-Yau manifold, X, are in 1-1 correspondence with objects in D(X), the derived category of coherent sheaves on X. We study the action of the monodromies in Kaehler moduli space on these D-branes. We refine and extend a conjecture of Kontsevich about the form of one of the generators of these monodromies (the monodr

M. Suzuki

The polarization measurement in the inclusive B decay provides us with a simple test of how much the long-distance final-state interaction takes place as the energy of the observed meson varies in the final state. We give the expectation of the perturbative QCD for the energy dependence of the helicity fractions in a semiquantitative form. Experiment will te

J. Bartels, D. Colferai, G. P. Vacca

In this paper we complete our calculation of the NLO jet vertex which is part of the cross section formulae for the production of Mueller Navelet jets at hadron hadron colliders and of forward jets in deep inelastic electron proton scattering.

V. P. Gusynin, V. A. Miransky, I. A. Shovkovy

This is a comment on the paper ``Electron Mass Operator in a Strong Magnetic Field and Dynamical Chiral Symmetry Breaking" by A. V. Kuznetsov and N. V. Mikheev [Phys. Rev. Lett. 89 (2002) 011601]. We show that the main conclusions of the paper are incorrect.

Einan Gardi

Power corrections to differential cross sections near a kinematic threshold are analysed by Dressed Gluon Exponentiation. Exploiting the factorization property of soft and collinear radiation, the dominant radiative corrections in the threshold region are resummed, yielding a renormalization-scale-invariant expression for the Sudakov exponent. The interplay

J. Blümlein, H. Böttcher

In this talk results from a new QCD analysis in leading (LO) and next--to--leading (NLO) order are presented. New parametrizations of the polarized quark and gluon densities are derived together with parametrizations of their fully correlated 1$σ$ error bands. Furthermore the value of $α_s(M_Z^2)$ is determined. Finally a number of low moments of the polariz

O. Nachtmann

We relate the structure functions of deep inelastic lepton-nucleon scattering to current-current correlation functions in a Euclidean field theory depending on a parameter r. The r-dependent Hamiltonian of the theory is P0-(1-r)P3, with P0 the usual Hamiltonian and P3 the third component of the momentum operator. We show that small x in the structure functio

Aldo Deandrea

The charged Higgs decay in the channel H^- ->tau_L^- nu in models with a singlet neutrino can provide a test of large extra dimensions models with TeV scale quantum gravity since in the standard two Higgs doublet model type II, H^- -> tau_L^- nu is suppressed. In the present study, we focus on the decay H^- -> tau_L^- nu at the LHC for Higgs masses larger th

Nita Sinha

In the presence of penguin contributions, the indirect CP asymmetry in B0(t)->pi+ pi- measures some effective (``polluted'') angle 2alpha_{eff}. The angle 2theta=2alpha_{eff}-2alpha, parameterizes the size of the penguin pollution. A new, most stringent upper bound on |2theta|, requiring the measurement of of BR(B+ -> pi+ pi0) and an upper bound on B

A. Kolchuzhkin, A. Potylitsyn, S. Strokov

The problem of electrons energy spread in the linear back Compton scattering process has been considered in the paper. The adjoint kinetic equation for the electrons passing through a laser flash has been obtained and used to get the equations for the mean energy and the variance of the energy distribution. The equations for the distribution moments have bee

M. Glück, E. Reya

New polarized fragmentation functions are introduced and justified, in addition to those conventional ones assumed to be independent of the helicity of the parent parton. It is demonstrated that due to our present ignorance concerning these new parton-spin dependent leading-twist fragmentation functions, it is impossible to utilize current experiments on spi

Matteo Beccaria, Antonio Moro

The Meron Cluster algorithm solves the sign problem in a class of interacting fermion lattice models with a chiral phase transition. Within this framework, we study the geometrical features of the clusters built by the algorithm, that suggest the occurrence of a generalized percolating phase transition at the chiral critical temperature in close analogy with

G. van der Steenhoven

A summary is given of some important developments in QCD studies of the nucleon as presented at this workshop. Based on these developments some expectations for the short- and long-term future of the field are sketched. Taken together, the summary of the workshop and the future perspectives result in a {\sl Road Map} for experimental studies of the QCD struc

ALEPH Collaboration

Single top production via the flavour changing neutral current reactions e+e- -> \bar{t}c, \bar{t}u is searched for within the 214 pb-1 of data collected by ALEPH at centre-of-mass energies between 204 and 209 GeV. No deviation from the Standard Model expectation is observed and upper limits on the single top production cross sections are derived. The combin

J. M. Link

Using data collected by the Fermilab experiment FOCUS, we measure the lifetime of the charmed baryon (Ξ_{c}^{o}) using the decay channels (Ξ_{c}^{o}\to Ξ^{-}π^{+}) and (Ξ_{c}^{o}\to Ω^{-}K^{+}). From a combined sample of (110\pm 17) events we find (τ(Ξ_{c}^{o}) =~118^{+ 14}_{- 12} \pm5) fs, where the first and second errors are statistical and systematic, re

Bahram Mashhoon, Uwe Muench

We investigate the limitations of length measurements by accelerated observers in Minkowski spacetime brought about via the hypothesis of locality, namely, the assumption that an accelerated observer at each instant is equivalent to an otherwise identical momentarily comoving inertial observer. We find that consistency can be achieved only in a rather limite

Shoji Yamamoto

We investigate localized intragap states in mixed-valence bimetal chains in an attempt to encourage further explorations into quasi-one-dimensional halogen-bridged binuclear metal (MMX) complexes. Within a coupled electron-phonon model, soliton and polaron excitations in the two distinct ground states of MMX chains are numerically calculated and compared. Ma

Hiromitsu Hori, Shoji Yamamoto

In order to investigate quantum and thermal phase transitions in the Bechgaard salts and their sulfur analogs, we perform finite-temperature Hartree-Fock calculations in one dimension with particular emphasis on the interplay between charge ordering and lattice instability. The coexisting charge- and spin-density-wave state as well as its precursor fluctuati

Takashi Nakanishi, Shoji Yamamoto

Motivated by recent magnetic measurements on A3Cu3(PO4)4 (A=Ca,Sr) and Cu(3-Clpy)2(N3)2 (3-Clpy=3-Chloropyridine), both of which behave like one-dimensional ferrimagnets, we extensively investigate the ferrimagnetic specific heat with particular emphasis on its double-peak structure. Developing a modified spin-wave theory, we reveal that ferromagnetic and an

Hiromitsu Hori, Shoji Yamamoto

Employing the Jordan-Wigner transformation on a unique path and then making a mean-field treatment of the fermionic Hamiltonian, we semiquantitatively describe the spin-gap states of Heisenberg ladders in a field. The appearance of magnetization plateaux is clarified as a function of the number of legs.

Shoji Yamamoto, Toru Sakai, Akihisa Koga

In response to recent chemical attempts to construct higher-spin ladder materials from organic polyradicals, we study the ground-state properties of a wide class of antiferromagnetic spin-1 ladders. Employing various numerical tools, we reveal the rich phase diagram and correct a preceding nonlinear-sigma-model prediction. A variational analysis well interpr

Prashant Damle, Avik W. Ghosh, Supriyo Datta

We present a rigorous and computationally efficient method to do a parameter-free analysis of molecular wires connected to contacts. The self-consistent field approach is coupled with Non-equilibrium Green's Function (NEGF) formalism to describe electronic transport under an applied bias. Standard quantum chemistry software is used to calculate the self-

B. Meyer, Dominik Marx

An extensive theoretical investigation of the nonpolar (10$\bar{1}$0) and (11$\bar{2}$0) surfaces as well as the polar zinc terminated (0001)--Zn and oxygen terminated (000$\bar{1}$)--O surfaces of ZnO is presented. Particular attention is given to the convergence properties of various parameters such as basis set, k--point mesh, slab thickness, or relaxatio

M. Kellogg, J. P. Eisenstein, L. N. Pfeiffer, K. W. West

Measurements and calculations of Coulomb drag between two low density, closely spaced, two-dimensional electron systems are reported. The experimentally measured drag exceeds that calculated in the random phase approximation by a significant, and density dependent, factor. Studies of the dependence of the measured drag on the difference in density between th

M. Eschrig, M. R. Norman

We present a theoretical model which accounts for recent angle resolved photoemission data in bilayer cuprate superconductors. Lineshapes and dispersions of the various bonding and antibonding features in the spectra are quantitatively reproduced. The observed dispersion anomalies are consistent with the interaction of electrons with a bosonic mode which is

H. E. Stanley, M. C. Barbosa, S. Mossa, P. A. Netz

We review recent results of molecular dynamics simulations of two models of liquid water, the extended simple point charge (SPC/E) and the Mahoney-Jorgensen transferable intermolecular potential with five points (TIP5P), which is closer to real water than previously-proposed classical pairwise additive potentials. Simulations of the TIP5P model for a wide ra

Y. J. Kim, J. P. Hill, C. A. Burns, S. Wakimoto

We report a resonant inelastic x-ray scattering study of the dispersion relations of charge transfer excitations in insulating La$_2$CuO$_4$. These data reveal two peaks, both of which show two-dimensional characteristics. The lowest energy excitation has a gap energy of $\sim 2.2$ eV at the zone center, and a dispersion of $\sim 1$ eV. The spectral weight o

S. Das Sarma, Jaroslav Fabian, Igor Zutic

In spin-polarized bipolar transport both electrons and holes in doped semiconductors contribute to spin-charge coupling. The current conversion between the minority (as referred to carriers and not spin) and majority carriers leads to novel spintronic schemes if nonequilibrium spin is present. Most striking phenomena occur in inhomogeneously doped magnetic {

J. Schulenburg, J. Richter

We study the frustrated dimer-plaquette quantum spin chain for ferromagnetic dimer bonds. This quantum system undergoes a series of first-order ground-state phase transitions driven by frustration or by a magnetic field. We find that the different nature of the ground-state phases has a strong influence on the magnetization curve as well as the low-temperatu

M. A. Ahrens, A. Schadschneider, J. Zittartz

We use the matrix product approach to construct all optimum ground states of general anisotropic spin-2 chains with nearest neighbour interactions and common symmetries. These states are exact ground states of the model and their properties depend on up to three parameters. We find three different antiferromagnetic Haldane phases, one weak antiferromagnetic

A. T. Boothroyd, D. Prabhakaran, P. G. Freeman, S. J. S. Lister

Polarized and unpolarized neutron inelastic scattering has been used to measure the spin excitations in the spin-charge-ordered stripe phase of La5/3Sr1/3NiO4. At high energies, sharp magnetic modes are observed characteristic of a static stripe lattice. The energy spectrum is described well by a linear spin wave model with intra- and inter-stripe exchange i

Beom Jun Kim, Ala Trusina, Petter Holme, Petter Minnhagen

A two-dimensional small-world type network, subject to spatial prisoners' dilemma dynamics and containing an influential node defined as a special node with a finite density of directed random links to the other nodes in the network, is numerically investigated. It is shown that the degree of cooperation does not remain at a steady state level but displa

Adilson E. Motter, Alessandro P. S. de Moura, Ying-Cheng Lai, Partha Dasgupta

We define two words in a language to be connected if they express similar concepts. The network of connections among the many thousands of words that make up a language is important not only for the study of the structure and evolution of languages, but also for cognitive science. We study this issue quantitatively, by mapping out the conceptual network of t

B. A. Bernevig, D. Giuliano, D. I. Santiago

We analyze the dynamics between 1/$λ$-fractional statistics particles (anyons) in an exact three-body solution of the Sutherland Hamiltonian. We show that anyons interact by means of a short-range attraction. The interaction dictates important features of the spectral function for a charge-1 particle.

Jay D. Salmonson

A strong correlation is reported between gamma-ray burst (GRB) pulse lags and afterglow jet-break times for the set of bursts (seven) with known redshifts, luminosities, pulse lags, and jet-break times. This may be a valuable clue toward understanding the connection between the burst and afterglow phases of these events. The relation is roughly linear (i.e.

Robert A. Simcoe, Wallace L. W. Sargent, Michael Rauch

We describe a survey for OVI absorption in the spectra of 5 high redshift quasars (2.2 < z < 2.8). We identify 12 cosmological systems, and 6 systems that are either ejected from the background QSO or affected by its local radiation field. Almost all of the intergalactic OVI is associated with strong Ly-a absorption (N_HI > 10^15.2 cm^-2), as well as absorpt

Charles R. Keeton

Strong gravitational lensing has traditionally been one of the few phenomena said to oppose a large cosmological constant; many analyses of lens statistics have given upper limits on $Ω_Λ$ that are marginally inconsistent with the concordance cosmology. Those conclusions were based on models where the predicted number counts of galaxies at moderate redshifts

L. J. Kewley, M. A. Dopita

We have used a combination of stellar population synthesis and photoionization models to develop a set of ionization parameter and abundance diagnostics based only on the use of the strong optical emission lines. These models are applicable to both extragalactic HII regions and star-forming galaxies. We show that, because our techniques solve explicitly for

D. J. Patnaude, R. A. Fesen, J. C. Raymond, N. A. Levenson

Spatially resolved ROSAT X-ray and ground-based optical data for the southwestern region of the Cygnus Loop SNR reveal in unprecedented detail the very early stages of a blast wave interaction with an isolated interstellar cloud. Numerous internal cloud shock fronts near the upstream flow and along the cloud edges are visible optically as sharp filaments of

C. B. Markwardt, J. H. Swank, T. E. Strohmayer, J. J. M. in &#39;t Zand

We report the discovery by the RXTE PCA of a second transient accreting millisecond pulsar, XTE J1751-305, during regular monitoring observations of the galactic bulge region. The pulsar has a spin frequency of 435 Hz, making it one of the fastest pulsars. The pulsations contain the signature of orbital Doppler modulation, which implies an orbital period of

D. W. Hoard, P. Szkody, R. Ishioka, L. Ferrario

We present the first far-ultraviolet (FUV) observations of the magnetic cataclysmic variable VV Puppis, obtained with the Far Ultraviolet Spectroscopic Explorer satellite. In addition, we have obtained simultaneous ground-based optical photometric observations of VV Pup during part of the FUV observation. The shapes of the FUV and optical light curves are co

J. Ahrens

We report on a search for electromagnetic and/or hadronic showers (cascades) induced by a diffuse flux of neutrinos with energies between 5 TeV and 300 TeV from extraterrestrial sources. Cascades may be produced by matter interactions of all flavors of neutrinos, and contained cascades have better energy resolution and afford better background rejection than

E. Lellouch, R. Moreno, J. L. Ortiz, G. Paubert

We report on coordinated thermal and optical measurements of trans-Neptunian object (20000) Varuna obtained in January-February 2002, respectively from the IRAM 30-m and IAA 1.5 m telescopes. The optical data show a lightcurve with a period of 3.176+/-0.010 hr, a mean V magnitude of 20.37+/-0.08 and a 0.42+/-0.01 magnitude amplitude. They also tentatively in

H. Liszt

The random error of radioastronomical measurements is usually computed in the weak-signal limit, which assumes that the system temperature is sensibly the same on and off source, or with and without a spectral line. This assumption is often very poor. We give examples of common situations in which it is important to distinguish the system noise in signal-bea

O. Petruk

Possibility to model the high energy synchrotron emission (in X- and gamma-rays) from supernova remnants is an important task for modern astronomy and astrophysics, because it may be responsible for the nonthermal X-rays and TeV gamma-rays observed recently from a number of SNRs. This emission allows as to look in the processes of particle acceleration on SN

L. Costamante, G. Ghisellini, A. Celotti, A. Wolter

With its very wide energy band (0.1-100 keV), BeppoSAX has played a fundamental role in the blazar field, allowing in particular a better study of the highest synchrotron peaked objects. Here we summarize the results of an observational program performed with the aim to find and study more extreme BL Lac sources. We discuss the SEDs of the observed objects a

D. Vergani, G. Gentile, R. -J. Dettmar, G. Aronica

We present our investigation on the effect of warps on the extraction of rotation curves in edge-on galaxies. The method to derive the rotation curve from the position-velocity diagram in warped edge-on systems yields underestimated velocities, and the tilted-ring model is not reliable in highly inclined, poorly resolved galaxies. In a warped system the kine

J. N. Reeves, D. Watson, J. P. Osborne, K. A. Pounds

We report on an XMM-Newton observation of the X-ray afterglow of the Gamma Ray Burst GRB 011211, originally detected by Beppo-SAX on 11th December 2001. The early afterglow spectrum obtained by XMM-Newton, observed 11 hours after the initial burst, appeared to reveal decaying H-like K emission lines of Mg, Si, S, Ar and Ca, arising in enriched material with

Suzanne Talon, Pawan Kumar, Jean-Paul Zahn

We review the behavior of the oscillating shear layer produced by gravity waves below the surface convection zone of the Sun. We show that, under asymmetric filtering produced by this layer, gravity waves of low spherical order, which are stochastically excited at the base of the convection zone of late type stars, can extract angular momentum from their rad

J. Mikolajewska

The recent detection of resolved radio emission from AG Dra by MERLIN reported by Ogley et al. is discussed in the context of the wind environment and the physical parameters and geometry of this symbiotic binary system. In particular, it is shown that the two radio components are closely aligned with the binary axis, and their separation suggests their orig

V. S. Geroyannis, P. J. Papasotiriou

We study a white dwarf with differential rotation and magnetic field, for which the symmetry axis of the toroidal field, the magnetic axis of the poloidal field, and the principal axis I_3 coincide permanently. This common axis, so-called &#34;magnetic symmetry axis&#34;, inclines at a small angle relative to the spin axis of the model, the so-called &#34;tu

G. Meeus, J. Bouwman, C. Dominik, L. B. F. M. Waters

We analyse the optical and IR spectra, as well as the spectral energy distribution (UV to mm) of the candidate Herbig Ae star HD100453. This star is particular, as it shows an energy distribution similar to that of other isolated Herbig Ae/Be stars (HAEBEs), but unlike most of them, it does not have a silicate emission feature at 10 um, as is shown in Meeus

A. -Y. Zhou, Y. -L. Qiu

The time evolution behaviour of the superhumps of the dwarf nova 1RXS J232953.9+062814 is investigated with the wavelet analysis method. On the basis of two nights CCD photometry performed during its first superoutburst as well as other published brightness data, we reveal the superhump&#39;s time-dependence as a function of periods and time. Our light curve

Eduardo L. Martin, Gibor Basri, Yakiv Pavlenko, Yuri Lyubchik

We present high-resolution spectroscopic observations of the \ion{Li}{1} resonance line in a sample of 62 stars that belong to 31 common-proper motion pairs with twin F or G-type components. Photospheric abundances of lithium were derived by spectral synthesis analysis. For seven of the pairs, we have measured large lithium abundance differences. Eleven othe

N. Y. Yamasaki, T. Ohashi, T. Furusho

Chandra observation of the central region of the A1060 cluster of galaxies resolved X-ray emission from two giant elliptical galaxies, NGC 3311 and NGC 3309. The emission from these galaxies consists of two components, namely the hot interstellar medium (ISM) and the low-mass X-ray binaries (LMXBs). We found the spatial extent of the ISM component was much s

D. Gondek-Rosinska, W. Kluzniak, N. Stergioulas

The X-ray emission of RXJ1856.5-3754 has been found to coincide to unprecedented accuracy with that of a blackbody, of radius 5.8+-0.9 km for the measured parallax distance of 140 pc (Burwitz et al. 2001, Drake et al. 2002). If the emission is uniform over the whole surface of a non-rotating star, the mass of the star cannot exceed 0.75+-0.12 solar mass rega

V. Dobrosavljevic, D. Tanaskovic, A. A. Pastor

The emergence of glassy behavior of electrons is investigated for systems close to the disorder and/or interaction-driven metal-insulator transitions. Our results indicate that Anderson localization effects strongly stabilize such glassy behavior, while Mott localization tends to suppress it. We predict the emergence of an intermediate metallic glassy phase

A. A. Aligia

Using the Anderson model in the Kondo regime, we calculate the persistent current j in a ring with an embedded quantum dot (QD) as a function of the Aharonov-Bohm flux Phi for different ring length L, temperature T and broadening of the conduction states delta . For T=delta =0 and L >> xi, where xi is the Kondo screening length, Lj tends to the value for a n

Daisuke Nagai, Andrey V. Kravtsov

Recently, high-resolution Chandra observations revealed the existence of very sharp features in the X-ray surface brightness and temperature maps of several clusters (Vikhlinin et. al., 2001). These features, called ``cold fronts&#39;&#39;, are characterized by an increase in surface brightness by a factor >2 over 10-50 kpc, accompanied by a drop in temperat

J. -P. Blaizot, E. Iancu, A. Rebhan

We compare our previously proposed hard-thermal-loop (HTL) resummed calculation of quark number susceptibilities using a self-consistent two-loop approximation to the quark density with a recent calculation of the same quantity at the one-loop level in a variant of HTL-screened perturbation theory. Besides pointing out conceptual problems with the latter app

J. M. Miller, A. C. Fabian, J. J. M. in &#39;t Zand, C. S. Reynolds

Broad Fe K-alpha emission lines have recently been reported in a number of Galactic black holes. Such lines are useful accretion flow diagnostics because they may be produced at the inner accretion disk and shaped by relativistic effects, but in general they have only been observed at luminosities of L_X ~ 10^(37-38) erg/s in soft X-rays. The Galactic microq

Ulrich W. Heinz, Peter F. Kolb

We use hydrodynamics to generate freeze-out configurations for non-central heavy-ion collisions at present and future collider energies. Such collisions are known to produce strong elliptic flow. The accompanying space-time structure of the source at freeze-out is analyzed using pion interferometry. Between RHIC and LHC energies the source deformation in the