February 2001 arXiv papers — page 5

M. Ruiz, A. Efstathiou, D. M. Alexander, J. Hough

In the context of the unified model of Seyfert galaxies, we use observations from the literature and a radiative transfer model to investigate the near-IR to mm emission produced by the presumed torus in the Circinus galaxy, from 2microns to 1.3mm. From the infrared SED modelling, we find that the total luminosity (L_{IR}) in this wavelength range, consists

Martin Erdmann

Measurements of heavy quark production in electron-positron collisions are used to analyse the strong interactions between quarks and anti-quarks. A scaling behaviour is observed in distributions of the rapidity change of D*, B*, and B mesons. From these distributions information is obtained on the hadron formation time, effective quark masses, and the poten

W. N. Brandt, A. E. Hornschemeier, D. M. Alexander, G. P. Garmire

We present results from a 479.7 ks Chandra exposure of the Hubble Deep Field North (HDF-N) and its immediate vicinity. In our X-ray image, the deepest ever reported with a 0.5-2.0 keV flux limit of about 4.9 x 10^{-17} erg/cm^2/s, we detect four new HDF-N X-ray sources bringing the total number of such sources to 12. The new sources include two optically bri

Angelo Carollo, G. Massimo Palma, Christoph Simon, Anton Zeilinger

In a recent paper Bennett et al.[Phys. Rev.A 59, 1070 (1999)] have shown the existence of a basis of product states of a bipartite system with manifest non-local properties. In particular these states cannot be completely discriminated by means of bilocal measurements. In this paper we propose an optical realization of these states and we will show that they

Chan-Gyung Park, Changbom Park, Bharat Ratra, Max Tegmark

We present results from a first test of the Gaussianity of degree-scale cosmic microwave background (CMB) anisotropy. We investigate Gaussianity of the CMB anisotropy by studying the topology of CMB anisotropy maps from the QMAP and Saskatoon experiments. We also study the QMASK map, a combination map of the QMAP and Saskatoon data. We measure the genus from

Igor Devetak, Toby Berger

An upper bound on the low-entanglement remote state preparation (RSP) ebits vs. bits tradeoff curve (Bennett et al.,quant-ph/0006044) is found using techniques of classical information theory. We prove our coding scheme to be optimal amongst an important class of protocols, and conjecture the bound to be tight.

Steen Hannestad

We have studied cosmological constraints on the number and radii of possible large extra dimensions. If such dimensions exist, Kaluza-Klein (KK) modes are copiously produced at high temperatures in the early universe, and can potentially lead to unacceptable cosmological effects. We show that during reheating, large numbers of KK modes are produced. These mo

M. Buechler, G. Colangelo, J. Kambor, F. Orellana

We propose a new method to obtain the K -> pi pi amplitude from K -> pi which allows one to fully account for the effects of final state interactions. The method is based on a set of dispersion relations for the K -> pi pi amplitude in which the weak Hamiltonian carries momentum. The soft pion theorem, which relates this amplitude to the K -> pi amplitude, c

Valentina Riva

We study the reflection amplitudes of affine Toda field theories with boundary, following the ideas developed by Fring and Koberle and focusing our attention on the $E_{n}$ series elements, because of their interesting structure of higher order poles. We also investigate the corresponding minimal reflection matrices, finding, with respect to the bulk case, a

Andrej Gendiar, Tomotoshi Nishino

Three-dimensional (3D) $q$-state Potts models ($q$=3, 4, and 5) are studied by the tensor product variational approach (TPVA), which is a recently developed variational method for 3D classical lattice models. The variational state is given by a two-dimensional (2D) product of local factors, and is improved by way of self-consistent calculations assisted by t

M. Buechler, G. Colangelo, J. Kambor, F. Orellana

It has been recently suggested that it is possible to calculate the effect of final state interactions in K -> pi pi amplitudes by applying dispersive methods to the amplitude with the kaon off-shell. We critically reexamine the procedure, and point out the effects of the arbitrariness in the choice of the off-shell field for the kaon.

Sorin Solomon, Peter Richmond

Using the Generalised Lotka Volterra (GLV) model adapted to deal with muti agent systems we can investigate economic systems from a general viewpoint and obtain generic features common to most economies. Assuming only weak generic assumptions on capital dynamics, we are able to obtain very specific predictions for the distribution of social wealth. First, we

Mikhail Shaposhnikov, Peter Tinyakov

We show that a pure gauge theory in higher dimensions may lead to an effective lower-dimensional theory with massive vector field, broken gauge symmetry and no fundamental Higgs boson. The mechanism we propose employs the localization of a vector field on a lower-dimensional defect. No non-zero expectation values of the vector field components along extra di

Youngjai Kiem, Chanju Kim, Yoonbai Kim

We obtain Q-ball solutions in noncommutative scalar field theory with a global U(1) invariance. The Q-ball solutions are shown to be classically and quantum mechanically stable. We also find that "excited Q-ball" states exist for some class of scalar potentials, which are classically stable in the large noncommutativity limit.

W. J. Munro, K. Nemoto, A. G. White

Entanglement is a critical resource used in many current quantum information schemes. As such entanglement has been extensively studied in two qubit systems and its entanglement nature has been exhibited by violations of the Bell inequality. Can the amount of violation of the Bell inequality be used to quantify the degree of entanglement. What do Bell inequa

M. L. Nekrasov

A generalization of the on-mass-shell scheme of UV renormalization (the OMS-bar scheme) to the case of presence of unstable fundamental particles (like W and Z bosons) is proposed. Its basic ingredients are as follows: (i) the renormalized mass coincides with a real part of the position of the complex pole of the corresponding propagator, (ii) the imaginary

Mun-Seog Kim, C. U. Jung, J. Y. Kim, Jae-Hyuk Choi

The infinite-layer compound ACuO$_{2}$ (A $=$ alkaline-earth ions) is regarded as the most suitable material for exploring the fundamental nature of the CuO$_2$ plane because it does not contain a charge-reservoir block, such as a rock-salt or a fluorite like block. We report that superconductivity in the infinite-layer compound Sr$_{0.9}$La$_{0.1}$CuO$_2$ i

A. Panaitescu

The parameters of the GRB 000301c afterglow are determined within the usual framework of synchrotron emission from relativistic ejecta, through fits to the available radio-to-optical data. It is found that 1) the jet energy after the GRB phase is ~3x10^{50} erg, 2) the initial opening angle of the jet is ~13 deg, 3) the medium that decelerates the afterglow

Vladimir L. Safonov

A single mode realization of SU(1,1) algebra is proposed. This realization makes it possible to reduce the problem of two nonlinear interacting oscillators to the problem of free moving particle.

Christoph Simon, Vladimir Buzek, Nicolas Gisin

We show that the basic dynamical rules of quantum physics can be derived from its static properties and the condition that superluminal communication is forbidden. More precisely, the fact that the dynamics has to be described by linear completely positive maps on density matrices is derived from the following assumptions: (1) physical states are described b

Mang Feng

The desired interference required for quantum computing may be modified by the wave function oscillations for the implementation of quantum algorithms[Phys.Rev.Lett.84(2000)1615]. To diminish such detrimental effect, we propose a scheme with trapped ion-pairs being qubits and apply the scheme to the Grover search. It can be found that our scheme can not only

P. Busch, G. Cassinelli, E. De Vito, P. Lahti

We give a description of the teleportation of an unknown quantum state which takes into account the action of the measuring device and manifestly avoids any reference to the postulate of the state vector collapse.

Masahito Hayashi

The author studies the Cramér-Rao type bound by a linear programming approach. By this approach, he found a necessary and sufficient condition that the Cramér-Rao type bound is attained by a random measurement. In a spin 1/2 system, this condition is satisfied.

A. Adamczak, M. P. Faifman

The rate of $ddμ$ muonic molecule resonant formation in $dμ$ atom collision with a condensed deuterium target is expressed in terms of a single-particle response function. In particular, $ddμ$ formation in solid deuterium at low pressures is considered. Numerical calculations of the rate in the case of fcc polycrystalline deuterium at 3 K have been performed

B. G. Sidharth

Much of twentieth century physics, whether it be Classical or Quantum, has been based on the concept of spacetime as a differentiable manifold. While this work has culminated in the standard model, it is now generally accepted that in the light of recent experimental results, we have to go beyond the standard model. On the other hand Quantum SuperString Theo

V. I. Berezhiani, S. M. Mahajan, Z. Yoshida, M. Ohhashi

Interaction of an intense electromagnetic (EM) beam with hot relativistic plasma is investigated. It is shown that the thermal pressure brings about a fundamental change in the dynamics - localized, high amplitude, EM field structures, not accessible to a cold (but relativisic) plasma, can now be formed under well- defined conditions. Examples of the trappin

Akihito Kikuchi, Shinji Tsuneyuki

The pressure-induced structural transition in fcc C$_{60}$ fullerene by shock compression and rapid quenching is investigated by a semi-empirical tight-binding molecular dynamics simulation, adopting a constant-pressure scheme and a method of the order N electronic structure calculation. At first, the process of the amorphization of C$_{60}$ is demonstrated.

R. Huerta, J. Wudka

We consider quantum systems which interact strongly with a rapidly varying environment and derive a Schrodinger-like equation which describes the time evolution of the average wave function. We show that the corresponding Hamiltonian can be taken to be Hermitian provided all states are rotated using an appropriate unitary transformation. The formalism is app

Chueng-Ryong Ji, Pieter Maris

The rainbow truncation of the quark Dyson-Schwinger equation is combined with the ladder Bethe-Salpeter equation for the meson bound state amplitudes and the dressed quark-W vertex in a manifestly covariant calculation of the K_{l3} transition form factors and decay width in impulse approximation. With model gluon parameters previously fixed by the chiral co

S. Liran, A. Marinov, N. Zeldes

We present two tables of calculated masses of translead nuclei, for 351 nuclei with N from 94 to 126 and Z from 82 to 100, and for 1969 nuclei with N from 126 to 184 and Z from 82 to 126. The tables are calculated from a semiempirical shell-model mass equation based on Z = 126 as a proton magic number which seems to be highly extrapolatable inside shell regi

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

The possible occurence of highly deformed configurations is investigated in the $^{40}$Ca and $^{56}$Ni di-nuclear systems as formed in the $^{28}$Si+$^{12}$C,$^{28}$Si reactions by using the properties of emitted light charged particles. Inclusive as well as exclusive data of the heavy fragments and their associated light charged particles have been collect

Ayse Karasu, Atalay Karasu, Sergei Sakovich

It is shown that a generalized Ito system of four coupled nonlinear evolution equations passes the Painleve test for integrability in five distinct cases, of which two were introduced recently by Tam, Hu and Wang. A conjecture is formulated on integrability of a vector generalization of the Ito system.

Marcelo Kuperman, Guillermo Abramson

We propose a generalization of small world networks, in which the reconnection of links is governed by a function that depends on the distance between the elements to be linked. An adequate choice of this function lets us control the clusterization of the system. Control of the clusterization, in turn, allows the generation of a wide variety of topologies.

H. R. Lourenco, O. C. Martin, T. Stutzle

This is a survey of "Iterated Local Search", a general purpose metaheuristic for finding good solutions of combinatorial optimization problems. It is based on building a sequence of (locally optimal) solutions by: (1) perturbing the current solution; (2) applying local search to that modified solution. At a high level, the method is simple, yet it al

Stefano Galatolo

We give a definition of generalized indicators of sensitivity to initial conditions and orbit complexity (a measure of the information that is necessary to describe the orbit of a given point). The well known Ruelle-Pesin and Brin-Katok theorems, combined with Brudno's theorem give a relation between initial data sensitivity and orbit complexity that is

Wayne Rossman, Masaaki Umehara, Kotaro Yamada

We survey our recent results on classifying complete constant mean curvature 1 (CMC-1) surfaces in hyperbolic 3-space with low total curvature. There are two natural notions of "total curvature"-- one is the total absolute curvature which is the integral over the surface of the absolute value of the Gaussian curvature, and the other is the dual total

Susumu Hirose

We show that, if g is more than or equal to 2, the virtual cohomological dimension of the mapping class group of a 3-dimensional handlebody of genus g is equal to 4g-5 and the Euler number of it is equal to 0.

O. S. M. Alves, S. Yu. Popov, F. P. Machado

In this work we prove a shape theorem for a growing set of Simple Random Walks (SRWs), known as frog model. The dynamics of this process is described as follows: There are some active particles, which perform independent SRWs, and sleeping particles, which do not move. When a sleeping particle is hit by an active particle, it becomes active too. We prove tha

S. Deser, A. Waldron

The (m^2,Λ) plane of spin s>1 massive fields in (A)dS backgrounds is shown to consist of separate phases, divided by lines of novel ``partially massless'' gauge theories that successively remove helicities, starting from the lowest, 0 or +/-(1/2). The norms of the excluded states flip as the gauge lines are crossed and only the region containing the

L. Hoffmann, T. Leonhardt, L. Mesref, W. Ruhl

We discuss the concept of composite fields in flat CFT as well as in the context of AdS/CFT. Furthermore we show how to represent Green functions using generalized hypergeometric functions and apply these techniques to four-point functions. Finally we prove an identity of $U(1)_Y$ symmetry for four-point functions.

O. V. Teryaev

These proceedings contain the 'physical' derivation of the Wandzura-Wilczek relations for the spin-dependent structure function g2 (amounting to keeping the intrinsic transverse momentum of quarks, and neglecting the physical transverse components of the gluon fields), recently generalized for the case of non-forward processes (hep-ph/0102209). The s

E. Lisi

Some aspects of the current neutrino oscillation phenomenology are briefly discussed, with emphasis on the status of mass-mixing parameters relevant for scenarios with three active neutrinos, and with an additional fourth sterile neutrino.

S. Munier, A. M. Stasto, A. H. Mueller

We extract the S-matrix element for dipole-proton scattering using the data on diffractive electroproduction of vector mesons at HERA. By considering the full t dependence of this process we are able to reliably unfold the profile of the S-matrix for impact parameter values b>0.3 fm. We show that the results depend only weakly on the choice of the form for t

G. L. Fogli, E. Lisi, A. Palazzo, F. L. Villante

The Super-Kamiokande (SK) and the Sudbury Neutrino Observatory (SNO) experiments are monitoring the flux of B solar neutrinos through the electron energy spectrum from the reactions nu_{e,mu,tau} + e --> nu_{e,mu,tau} + e and nu_e + d --> p + p + e, respectively. We show that the SK detector response to B neutrinos in each bin of the electron energy spectrum

Ali H. Chamseddine, R. Arnowitt, Pran Nath

A review is given of the historical developments of 1982 that lead to the supergravity unified model (SUGRA)with gravity mediated breaking of supersymmetry. Further developments and applications of the model in the period 1982-85 are also discussed. The supergravity unified model and its minimal version (mSUGRA) are currently among the leading candidates for

S. Hegyi

In QCD, the similarity of multiplicity distributions is violated i) by the running of the strong coupling constant alpha_s and ii) by the self-similar nature of parton cascades. It will be shown that the data collapsing behavior of P_n onto a unique scaling curve can be restored by performing the original scaling prescription (translation and dilatation) in

M. L. Nekrasov

The processes $e^{+}e^{-} \to 4f(γ)$ mediated by W-pair (and single) production are considered in the framework of the modified perturbation theory, based on the expansion of probability in powers of the coupling constant instead of amplitude. A full set of one-loop corrections to cross-section, and two-loop corrections to self-energy of unstable particles a

M. Battaglia, M. Caccia, S. Borghi, R. Campagnolo

In order to fully exploit the physics potential of a e+e- linear collider, such as TESLA, a Vertex Tracker providing high resolution track reconstruction is required. Hybrid Silicon pixel sensors are an attractive sensor technology option due to their read-out speed and radiation hardness, favoured in the high rate TESLA environment, but have been so far lim

The DELPHI Collaboration, P. Abreu

Searches for spontaneous R-parity violating signals at sqrt(s) = 183 GeV and sqrt(s) = 189 GeV have been performed using the 1997 and 1998 DELPHI data, under the assumption of R-parity breaking in the third lepton family. The expected topology for the decay of a pair of charginos into two acoplanar taus plus missing energy was investigated and no evidence fo

Alessandra Buonanno, Thibault Damour

In pre-big-bang string cosmology one uses a phase of dilaton-driven inflation to stretch an initial (microscopic) spatial patch to the (much larger) size of the big-bang fireball. We show that the dilaton-driven inflationary phase does not naturally iron out the initial classical tensor inhomogeneities unless the initial value of the string coupling is small

Lane A. Hemaspaandra, Harald Hempel

No P-immune set having exponential gaps is positive-Turing self-reducible.

M. H. van Emden

This note addresses the input and output of intervals in the sense of interval arithmetic and interval constraints. The most obvious, and so far most widely used notation, for intervals has drawbacks that we remedy with a new notation that we propose to call factored notation. It is more compact and allows one to find a good trade-off between interval width

Jason Eisner, Lauri Karttunen, Alain Theriault

Home page of the workshop proceedings, with pointers to the individually archived papers. Includes front matter from the printed version of the proceedings.

R. S. Markiewicz, C. Kusko

A phase separation model for stripes has found good agreement with photoemission experiments and with other studies which suggest a termination of the striped phase in the slightly overdoped regime. Here the model is extended in a number of respects. In particular, a discussion of the nature of the charged stripes is presented, suggesting how density waves,

D. Das, S. Doniach

In this paper, we extend our previous discussion of the Bose metal to the field tuned case. We point out that the recent observation of the metallic state as an intermediate phase between the superconductor and the insulator in the field tuned experiments on MoGe films is in perfect consistency with the Bose metal scenario. We establish a connection between

C. Kusko, R. S. Markiewicz

A mean field calculation of the Hubbard model finds a rich phase diagram. The antiferromagnetic phase is generally unstable away from half filling, and there are several regions of phase separation. One solution in particular closely resembles the stripe phase of White and Scalapino. By comparison to unrestricted Hartree-Fock calculations (for which this pha

R. D. Duncan, C. D. Vaccarella, C. A. R. Sá de Melo

Recent experiments indicate that the Bechgaard salts (TMTSF)$_2$ ClO$_4$ and (TMTSF)$_2$ PF$_6$ may be unconventional triplet superconductors. The quasiparticle density of states and the uniform spin susceptibility tensor are computed at low temperatures for order parameter symmetries, as an attempt to narrow the number of possibilities based on experimental

M. A. Quijada, J. R. Simpson, H. D. Drew, J. W. Lynn

We report on the optical properties of undoped single crystal LaMnO_3, the parent compound of the colossal magneto-resistive manganites. Near-Normal incidence reflectance measurements are reported in the frequency range of 20-50,000 cm-1 and in the temperature range 10-300 K. The optical conductivity, s_1(w), is derived by performing a Kramers-Kronig analysi

I. G. Gurtubay, J. M. Pitarke, I. Campillo, A. Rubio

We have investigated the role of localized {\it d} bands in the dynamical response of Au, on the basis of {\it ab initio} pseudopotential calculations. The density-response function has been evaluated in the random-phase approximation. For small momenta, we have found a double peak structure in the energy-loss function, which results from the presence of {\i

J. R. Thompson, A. V. Silhanek, L. Civale, K. J. Song

For a single crystal of YNi(2)B(2)C superconductor, the equilibrium magnetization M in the square basal plane has been studied experimentally as a function of temperature and magnetic field. While the magnetization M(H) deviates from conventional London predictions, a recent extension of London theory (to include effects of non-local electrodynamics) describ

Pep Español

Following a cell-method due to van Kampen for the calculation of a coarse-grained free energy functional for the van der Waals gas, we compute a corresponding entropy functional from microscopic principles. This entropy functional is one of the building blocks of the recently developed GENERIC framework. This framework allows to obtain in a thermodynamically

Armen E. Allahverdyan, Roger Balian, Theo M. Nieuwenhuizen

A model of quantum measurement is proposed, which aims to describe statistical mechanical aspects of this phenomenon, starting from a purely Hamiltonian formulation. The macroscopic measurement apparatus is modeled as an ideal Bose gas, the order parameter of which, that is, the amplitude of the condensate, is the pointer variable. It is shown that propertie

S. Raymond, L. P. Regnault, J. Flouquet, A. Wildes

Inelastic neutron scattering experiments performed on a single crystal of the antiferromagnetic compound Ce$_{0.87}$La$_{0.13}$Ru$_{2}$Si$_{2}$ under applied pressures of up to 5 kbar are reported. A quantum critical point is reached at around 2.6 kbar where long-range magnetic order disappears. The variation of the characteristic energy scales with respect

A. Bäker, L. Schweitzer

The frequency dependent transport is investigated for a two-dimensional disordered system under QHE conditions. The real and imaginary parts of the conductivity are calculated numerically in linear response using a recursive Green function technique. The energy dependence of $σ_{xx}(E,ω)$ is obtained within the lowest Landau band. When the width of the syste

P. A. Marchetti, Zhao-bin Su, Lu Yu

The metal-insulator crossover of the in-plane resistivity upon temperature decrease, recently observed in several classes of cuprate superconductors, when a strong magnetic field suppresses the superconductivity, is explained using the $U(1)\times SU(2)$ Chern-Simons gauge field theory. The origin of this crossover is the same as that for a similar phenomeno

A. Gerashenko, K. Mikhalev, S. Verkhovskii, T. D'yachkova

NMR spectra and nuclear spin-lattice relaxation rate $T_1^{-1}$ of $^{11}$B have been measured in superconducting polycrystalline MgB$_{2}$ with $T_C^{ons}\cong 39.5K$. It is shown that $(T_{1}T)^{-1}$ and the Knight shift $K_{s}$ are independent of temperature and nearly isotropic above $T_C$. Both of these quantities are decreased gradually in going to sup

J. Hwang, H. Noh

We consider the large-scale cosmic structure generation by an inflation based on a pure f(R)-type gravity theory. Comparison with recent CMBR observations gives the following results: (1) The near Zel'dovich spectral conditions uniquely choose R^2-type gravity. (2) The R^2 gravity predicts specific nearly scale-invariant Zel'dovich spectra for both t

D. Alloin, E. Galliano, J. G. Cuby, O. Marco

We present results about the distribution and kinematics of the molecular environment of the AGN in NGC1068, over a 1.5'' x 3.5'' region around the central engine in NGC1068, derived from H2 line emission detected with ISAAC at VLT/ANTU on ESO/Paranal. The H2 emitting molecular gas is found to be distributed along the East-West direction and

H. Schatz, A. Aprahamian, V. Barnard, L. Bildsten

We calculate the rapid proton (rp) capture process of hydrogen burning on the surface of an accreting neutron star with an updated reaction network that extends up to Xe, far beyond previous work. In both steady-state nuclear burning appropriate for rapidly accreting neutron stars (such as the magnetic polar caps of accreting X-ray pulsars) and unstable burn

A. M. Serenelli, L. G. Althaus, R. D. Rohrmann, O. G. Benvenuto

The purpose of this work is to explore the evolution of helium-core white dwarf stars in a self-consistent way with the predictions of detailed non-gray model atmospheres and element diffusion. To this end, we consider helium-core white dwarf models with stellar masses of 0.406, 0.360, 0.327, 0.292, 0.242, 0.196 and 0.169 solar masses and follow their evolut

Paul J. Groot

Time resolved spectroscopic observations of U Gem during its March 2000 outburst show strong spiral shocks in the accretion disk. During the plateau at maximum brightness the spiral shocks contribute 14% to the total He II flux. The two arms of the spiral show a distinctly different evolution during the outburst and decline, which indicates an asymmetric evo

S. Bogovalov

A stationary self-consistent outflow of a magnetised relativistic plasma from a rotating object with an initially monopole-like magnetic field is investigated in the ideal MHD approximation under the condition $σ/U_0^2 >1$, where $σ$ is the ratio of the Poynting flux over the mass energy flux at the equator and the surface of the star, with $U_0=γ_0v_0/c$ an

Felix Ryde, Roland Svensson

We find and study a variety of the spectral-temporal behavior during the decay phase of the light curve of long and bright pulse structures in gamma-ray bursts. It was earlier found that for about half of these decays, the instantaneous photon flux is consistent with a power law in time, where the photon flux $\propto$ 1/time. This decay behavior is a conseq

S. Holland

We used 45 orbits of Hubble Space Telescope time in Cycle 9 to obtain deep STIS/CCD images of the host galaxies of eleven gamma-ray bursts. Our goals are to study the morphologies of the host galaxies, to obtain precise locations of gamma-ray bursts within their host galaxies, and to determine star-formation rates in the hosts. We present preliminary results

E. Marchetti, R. Faraggiana, P. Bonifacio

A search for duplicity of lambda Bootis stars has been made by using the speckle camera installed at the Telescopio Nazionale Galileo. The operation mode and the reduction procedure allow one to obtain not only the separation, but also the magnitude difference between the components; the latter parameter is fundamental for determining the degree of contamina

S. L. Snowden, K. Mukai, W. Pence, K. D. Kuntz

Using a deep Chandra AO-1 observation of the face-on spiral galaxy M101, we examine three of five previously optically-identified X-ray sources which are spatially correlated with optical supernova remnants (MF54, MF57, and MF83). The X-ray fluxes from these objects, if due to diffuse emission from the remnants, are bright enough to require a new class of ob

Xavier Dupac, M. Giard, J. -P. Bernard, J. -M. Lamarre

We present here the continuum submillimeter maps of the molecular cloud around the M42 Nebula in the Orion region. These have been obtained in four wavelength bands (200, 260, 360 and 580 microns) with the ProNaOS two meter balloon-borne telescope. The area covered is 7 parsecs wide (50 arcmin at a distance of 470 pc) with a spatial resolution of about 0.4 p

R. Duemmler, V. Aarum

UX Ari belongs to the class of very active RS CVn stars and has recently been the target of surface (Doppler) imaging. Although this technique needs a quite accurate determination of the orbit (in order to have the correct period for phasing and the correct Doppler shift correction of the line profiles) we found only one, quite old orbit solution, which has

D. M. Crenshaw, S. B. Kraemer, F. C. Bruhweiler, J. R. Ruiz

We have obtained low-dispersion spectra of NGC 3227 with the Space Telescope Imaging Spectrograph (STIS) to study the intrinsic UV absorption and the reddening of the nucleus in this Seyfert 1 galaxy. The UV spectra show a wealth of absorption lines at the systemic redshift that span a wide range in ionization state (Mg I to N V). The equivalent widths of th

Grazyna Stasinska

We discuss the role of the electron temperature in abundance determinations in ionized nebulae (planetary nebulae and giant HII regions). We show that, even when observations provide a direct estimate of Te, abundance determinations may sometimes be significantly in error for reasons other than hypothetical temperature fluctuations or uncertainties in ioniza

Arthur Kosowsky

This set of lectures provides an overview of the basic theory and phenomenology of the cosmic microwave background. Topics include a brief historical review; the physics of temperature and polarization fluctuations; acoustic oscillations of the primordial plasma; the space of inflationary cosmological models; current and potential constraints on these models

Mikhail V. Medvedev

The crisis of the cold dark matter and problems of the self-interacting dark matter models is resolved by postulating flavor mixing of dark matter particles. Flavor-mixed particles segregate in the gravitational field to form dark halos composed of heavy mass eigenstates. Since these particles are mixed in the interaction basis, elastic collisions convert so

Mikhail V. Medvedev

We present a theory of generation of strong (sub-equipartition) magnetic fields in relativistic collisionless GRB shocks. These fields produced by the kinetic two-stream instability are tangled on very small spatial scales. This has a clear signature in the otherwise synchrotron(-self-Compton) $γ$-ray spectrum. Second, we present an analytical theory of jitt

Mikhail V. Medvedev

We present analytical and numerical solutions which describe a hot, viscous, two-temperature accretion flow onto a neutron star or any other compact star with a surface. We assume Coulomb coupling between the protons and electrons, and free-free cooling from the electrons. Outside a thin boundary layer, where the accretion flow meets the star, we show that t

Andrew Chamblin, Neil D. Lambert

In this note we study a massive IIA supergravity theory obtained in hep-th/9707139 by compactification of M-theory. We point out that de Sitter space in arbitrary dimensions arises naturally as the vacuum of this theory. This explicitly shows how de Sitter space can be embedded into eleven-dimensional supergravity. In addition we discuss the novel way in whi

Takashi Nakanishi, Shoji Yamamoto, Toru Sakai

Quantum and thermal behaviors of low-dimensional mixed-spin systems are investigated with particular emphasis on the design of molecule-based ferromagnets. One can obtain a molecular ferromagnet by assembling molecular bricks so as to construct a low-dimensional system with a magnetic ground state and then coupling the chains or the layers again in a ferroma

S. -H. Lee, Y. Qiu, C. Broholm, Y. Ueda

Inelastic neutron scattering is used to characterize spin fluctuations in the $d$-electron heavy fermion spinel $\rm LiV_2O_4$. The spin relaxation rate, $Γ_Q$, for $Q=0.6$ Å$^{-1}$ is 1.5(1) meV at low temperatures and increases linearly with temperature at a rate of 0.41(4) k$_B$. There is antiferromagnetic short range order at low temperatures with a char

S. L. Bud'ko, C. Petrovic, G. Lapertot, C. E. Cunningham

Detailed magneto-transport data on dense wires of $MgB_2$ are reported for applied magnetic fields up to 18 T. The temperature and field dependencies of the electrical resistivity are consistent with $MgB_2$ behaving like a simple metal and following a generalized form of Kohler's rule. In addition, given the generally high $T_c$ values and narrow resist

Bogdan Morariu, Alexios P. Polychronakos

We analyze the algebra of observables of a charged particle on a noncommutative torus in a constant magnetic field. We present a set of generators of this algebra which coincide with the generators for a commutative torus but at a different value of the magnetic field, and demonstrate the existence of a critical value of the magnetic field for which the alge

A. Nichols

We study four point correlation functions of the spin 1 operators in the SU(2)_0 WZNW model. The general solution which is everywhere single-valued has logarithmic terms and thus has a natural interpretation in terms of logarithmic conformal field theory. These are not invariant under all the crossing symmetries but can remain if fields possess additional qu

A. Bianconi, N. L. Saini, D. Di Castro, S. Agrestini

We report variation of lattice structure in diborides (AB2) with different A atoms to identify the special case of MgB2 showing high Tc superconductivity. High purity MgB2 (Tc~39 K) has been prepared by direct reaction of the elements and the lattice parameters are measured by x-ray diffraction determining the strain e of the B-B distance. The results show t

V. Ravindran, W. L. van Neerven

In this paper we study QCD and power corrections to sum rules which show up in deep inelastic lepton-hadron scattering. Furthermore we will make a distinction between fundamental sum rules which can be derived from quantum field theory and those which are of a phenomenological origin. Using current algebra techniques the fundamental sum rules can be expresse

D. O. Caldwell, R. N. Mohapatra, S. Yellin

String inspired models with millimeter scale extra dimensions provide a natural way to understand an ultralight sterile neutrino needed for a simultaneous explanation of the solar, atmospheric and LSND neutrino oscillation results. The sterile neutrino is the bulk neutrino ($ν_B$) postulated to exist in these models, and it becomes ultralight in theories tha

Laurent Berger

In this paper, we associate to every $p$-adic representation $V$ a $p$-adic differential equation $\mathbf{D}^{\dagger}_{\mathrm{rig}}(V)$, that is to say a module with a connection over the Robba ring. We do this via the theory of Fontaine's $(ϕ,Γ_K)$-modules. This construction enables us to relate the theory of $(ϕ,Γ_K)$-modules to $p$-adic Hodge theor

A. Bacchetta, R. Kundu, A. Metz, P. J. Mulders

The Collins function belongs to the class of the so-called time-reversal odd fragmentation functions. Being chiral-odd as well, it can serve as an important tool to observe the nucleon's transversity distribution in semi-inclusive DIS. Due to the possible presence of final state interactions, this function can be non-zero, though this has never been demo

R. Kerner, J. W. van Holten, R. Colistete

We solve the geodesic deviation equations for the orbital motions in the Schwarzschild metric which are close to a circular orbit. It turns out that in this particular case the equations reduce to a linear system, which after diagonalization describes just a collection of harmonic oscillators, with two characteristic frequencies. The new geodesic obtained by

Dimitry M. Gangardt, Alex Kamenev

Employing Forrester-Ha method of Jack polynomials, we derive an integral identity connecting certain N-fold coordinate average of the Calogero-Sutherland model with the n-fold replica integral. Subsequent analytical continuation to non-integer n leads to asymptotic expressions for the (static and dynamic) density-density correlation function of the model as

E. Il'ichev, M. Grajcar, R. Hlubina, R. P. J. IJsselsteijn

We have measured the current-phase relationship (CPR) of symmetric 45 degree YBaCuO grain boundary Josephson junctions. Substantial deviations of the CPR from conventional tunnel-junction behavior have been observed: (i) The critical current exhibits, as a function of temperature T, a local minimum at a temperature T*. (ii) At T approximately equal to T*, th

L. Polley

Quantum mechanics postulates the existence of states determined by a particle position at a single time. This very concept, in conjunction with superposition, induces much of the quantum-mechanical structure. In particular, it implies the time evolution to obey the Schroedinger equation, and it can be used to complete a truely basic derivation of the statist

S. Karnas, M. Lewenstein

We investigate separability and entanglement of mixed states in ${\cal C}^2\otimes{\cal C}^2\otimes{\cal C}^N$ three party quantum systems. We show that all states with positive partial transposes that have rank $\le N$ are separable. For the 3 qubit case (N=2) we prove that all states $ρ$ that have positive partial transposes and rank 3 are separable. We pr