December 1999 arXiv papers — page 19

N. S. Ananikian, R. G. Ghulghazaryan, N. Sh. Izmailian, R. R. Shcherbakov

The exact solution of a general Z(4) gauge Potts model with a single and double plaquette representation of the action is found on a subspace of gauge-coupling parameters on the square and triangular lattices. The two Ising-type critical lines of a second-order phase transition for the model on a square lattice are found. For the model on a triangular lattic

Konstantin G. Zloshchastiev

We propose the non-accelerator non-low-temperature simulator of quantum-field effects which is based on the feeder circuits with the special feedback. By means of it one can study the field models which contain fundamental concepts in the modern field theory but do not exist in nature in a separate form. Besides, several field phenomena might find technologi

P. Chaddah, S. B. Roy

We extend the classical theory for supercooling across first order phase transitions to the case when both density and temperature are control variables. The observable region of metastability then depends on the path followed in this space of two variables. Since the density of vortex matter in superconductors can be easily varied over a wide range by varyi

Mher M. Aghasyan, Albert A. Kirakosyan

Within the framework of staircase infinitely deep (SIW) potential well model the effect of dielectric constant mismatch between the size-quantized semiconducting wire, coating and surrounding environment on impurity binding energy is considered. Calculations are done in both the absence and presence of magnetic field applied along the wire axis. By the varia

Kihong Kim, Dong-Hun Lee

We develop an alternative formulation of the theory of solitons, polarons and multipolarons in quasi-one-dimensional degenerate and non-degenerate conducting polymers, starting from the continuum Hamiltonian introduced by Brazovskii and Kirova. Based on a convenient real-space representation of the electron Green function in one dimension, we present a simpl

Bikash C. Gupta, Sang Bub Lee

The modified discrete nonlinear Schrödinger equation is used to study the formation of stationary localized states in a one-dimensional lattice with a single impurity and an asymmetric dimer impurity. A periodically modulated and a perfectly nonlinear chain is also considered. Phase diagrams of localized states for all systems are presented. From the mean sq

N. B. Zhitenev, M. Brodsky, R. C. Ashoori, L. N. Pfeiffer

Single-electron capacitance spectroscopy precisely measures the energies required to add individual electrons to a quantum dot. The spatial extent of electronic wavefunctions is probed by investigating the dependence of these energies on changes in the dot confining potential. For low electron densities, electrons occupy distinct spatial sites localized with

G. Vacca, R. D. Morgan, R. B. Laughlin

We have developed a light scattering technique based on differential measurement and polarization (differential light scattering, DLS) capable in principle of retrieving timing information with picosecond resolution without the need for fast electronics. DLS was applied to sonoluminescence, duplicating known results (sharp turnaround, self-similar collapse);

Zoltan Neufeld, Peter H. Haynes, Guillemette Picard

The stationary distribution of passive tracers chaotically advected by a two-dimensional large-scale flow is investigated. The tracer field is force by resetting the value of the tracer in certain localised regions. This problem is mathematically equivalent to advection in open flows and results in a fractal tracer structure. The spectral exponent of the tra

Joerg Schumacher, Norbert Seehafer

A numerical bifurcation analysis of the electrically driven plane sheet pinch is presented. The electrical conductivity varies across the sheet such as to allow instability of the quiescent basic state at some critical Hartmann number. The most unstable perturbation is the two-dimensional tearing mode. Restricting the whole problem to two spatial dimensions,

Kirill N. Alekseev, Natasha V. Alekseeva, Jan Perina

We develop a semiclassical method for the determination of the nonlinear dynamics of dissipative quantum optical systems in the limit of large number of photons N, based on the 1/N-expansion and the quantum-classical correspondence. The method has been used to tackle two problems: to study the dynamics of nonclassical state generation in higher-order anharmo

J. Staren, P. Meinhold, J. Childers, M. Lim

We describe the HEMT Advanced Cosmic Microwave Explorer (HACME), a balloon borne experiment designed to measure sub-degree scale Cosmic Microwave Background anisotropy over hundreds of square degrees, using a unique two dimensional scanning strategy. A spinning flat mirror that is canted relative to its spin axis modulates the direction of beam response in a

Michael S. Turner

More than sixty years ago Zwicky made the case that the great clusters of galaxies are held together by the gravitational force of unseen (dark) matter. Today, the case is stronger and more precise: Dark, nonbaryonic matter accounts for 30% +/- 7% of the critical mass density, with baryons (most of which are dark) contributing only 4.5% +/- 0.5% of the criti

P. N. Appleton, V. Charmandaris, C. Horellou, I. F. Mirabel

Collisional ring galaxies probably result from a head-on collision between a compact companion galaxy and a gas-rich disk system. We present a review of the discovery of warm dust in five collisional rings observed by ISO which range in total Far-IR luminosity from 10$^{10}$~ $<$ ~L$_{FIR}$ ~$<$ ~10$^{11}$ L$\odot$. The results show that in most cases, the m

Xanthopoulos, N. J. Jackson, I. Snellen, J. Dennett-Thorpe

The CERES Astronomical Archive was created initially in order to make the large amount of data that were collected from the two surveys, the Jodrell-VLA Astrometric Survey (JVAS) and the Cosmic Lens All-Sky Survey (CLASS), easily accessible to the partner members of the Consortium for European Research on Extragalactic Surveys (CERES) through the web. Here w

Gerard A. Kriss, Bradley M. Peterson, D. Michael Crenshaw, Wei Zheng

From 1996 June 10 to 1996 July 29 the International AGN Watch monitored the Seyfert 1 galaxy NGC 7469 using IUE, RXTE, and a network of ground-based observatories. On 1996 June 18, in the midst of this intensive monitoring period, we obtained a high signal-to-noise snapshot of the UV spectrum from 1150-3300 A using the FOS on HST. This spectrum allows us to

Nikos Prantzos

We review the yields of intermediate mass elements (from C to Zn) from massive stars and their associated uncertainties, in the light of recent theoretical results. We consider the role of those yields for our understanding of the chemical evolution of the solar neighbourhood and of the halo of our Galaxy. Current yields reproduce in a satisfactory way the s

C Gottbrath, J Bailin, C Meakin, T Thompson

We show that, in the context of Moore&#39;s Law, overall productivity can be increased for large enough computations by `slacking&#39; or waiting for some period of time before purchasing a computer and beginning the calculation.

L. N. da Costa, M. Bernardi, M. V. Alonso, G. Wegner

This is the first in a series of papers describing the recently completed all-sky redshift-distance survey of nearby early-type galaxies (ENEAR) carried out for peculiar velocity analysis. The sample is divided into two parts and consists of 1607 elliptical and lenticular galaxies with cz < 7000 km/s and with blue magnitudes brighter than m_B=14.5 (ENEARm),

A. Herrero, J. Puls, M. R. Villamariz

We present observations and analyses of seven Galactic O stars of type O6 and earlier. Analyses are carried out using NLTE plane-parallel, hydrostatic models as well as NLTE spherical models with mass-loss. With detailed calculations for the former and simulations for the latter, it is shown that the flux blocking due to UV metal lines is important for these

J. M. Oliveira, B. H. Foing, Y. C. Unruh

SU Aurigae is a classical T Tauri star of spectral type G2. This star was one of the scientific targets of the MUSICOS 96 multi-site campaign that provided a wealth of high resolution cross-dispersed spectral data with a good continuous time coverage. We present the results of the analysis of the complex circumstellar environment of this star, with particula

Eleni T. Chatzichristou

The standard AGN unification models attempt to explain the diversity of observed AGN types by a few fundamental parameters, where orientation effects play a paramount role. Whether other factors, such as the evolutionary stage and the host galaxy properties are equally important parameters for the AGN diversity, is a key issue that we are addressing with the

A. P. Sarma, T. H. Troland, D. A. Roberts, R. M. Crutcher

We present OH and H I Zeeman observations of the NGC 6334 complex taken with the Very Large Array. The OH absorption profiles associated with the complex are relatively narrow (del-v_FWHM ~ 3 km s^1) and single-peaked over most of the sources. The H I absorption profiles contain several blended velocity components. One of the compact continuum sources in the

F. Hammer

Galaxy evolution during the last 9 Gyr is discussed. It can be traced back from well known present-day galaxies or directly observed for galaxies at different look back times. This requires clear and consistently matched selection criteria for galaxy samples. There is a net decrease of rest-frame, UV luminosity density, at least since z = 1. It is interprete

Viki Joergens, Karl-Heinz Mantel, Heinz Barwig, Otto Baernbantner

We performed time-resolved spectroscopic studies of the double-eclipsing dwarf nova EX Dra (formerly HS 1804 + 6753) in order to locate line emitting sites in the system. Optical spectra recorded during the quiescent as well as during the outburst state have been analysed by means of Doppler tomography. The computed Doppler images map the system in a variety

A. E. Chudakov, V. B. Petkov, V. Ya. Poddubny, A. V. Voevodsky

We present the experimental data on the knee, as observed in the electromagnatic and high energy muon (Eμ\ge 230 Gev) components.

Adam Frank

Theoretical Models for the shaping of PNe are reviewed in light of new high resolution images. The new data indicate the purely hydrodynamic interacting stellar winds model can not recover the full variety of shapes and kinematics. New models, some speculative, others more firmly grounded are discussed. In particular, accretion disks and magnetic fields are

G. Pietrzynski, A. Udalski

We present Cepheids located in the close neighborhood of star clusters from the Magellanic Clouds. 204 and 132 such stars were found in the LMC and SMC, respectively. The lists of objects were constructed based on catalogs of Cepheids and star clusters, recently published by the OGLE-II collaboration. Location of selected Cepheids on the sky indicates that m

A. B. Peck, G. B. Taylor

We present results of multifrequency polarimetric VLBA observations of 34 compact radio sources. The observations are part of a large survey undertaken to identify CSOs Observed in the Northern Sky (COINS). Compact Symmetric Objects (CSOs) are of particular interest in the study of the physics and evolution of active galaxies. Based on VLBI continuum surveys

A. B. Peck, G. B. Taylor, C. D. Fassnacht, A. C. S. Readhead

Compact Symmetric Objects (CSOs) are young radio galaxies whose jet axes lie close to the plane of the sky, and whose appearance is therefore not dominated by relativistic beaming effects. The small linear sizes of CSOs make them valuable for studies of both the evolution of radio galaxies and testing unified schemes for active galactic nuclei (AGN). A parse

G. Pietrzynski, A. Udalski, M. Kubiak, M. Szymanski

We present the catalog of star clusters found in the area of about 5.8 square degree in the central regions of the Large Magellanic Cloud. It contains data for 745 clusters. 126 of them are new objects. For each cluster equatorial coordinates, radius, approximate number of members and cross-identification are provided. Photometric data for all clusters prese

Annalisa Celotti, John C. Miller, Dennis W. Sciama

Following a short account of the history of the idea of black holes, we present a review of the current status of the search for observational evidence of their existence aimed at an audience of relativists rather than astronomers or astrophysicists. We focus on two different regimes: that of stellar-mass black holes and that of black holes with the masses o

A. V. Kopylov

The comparison of magnetic moments of neutron and proton reveals three possible stationary states of a nucleon: s-, p- and o-nucleon with different configurations and presumably different masses. Two of these nucleons may exist as the small impurities to the representative one. If so the frequency 1420405751.767 Hz of the hydrogen maser should be accompanied

Paolo Tozzi, Colin Norman

The thermodynamics of the diffuse, X-ray emitting gas in clusters and groups of galaxies are affected by a certain amount of non-gravitational energy input, as indicated by the scaling properties of X-ray halos. Such a view has been recently confirmed by the detection of an excess entropy in the center of groups. It is not easy, however, to identify unambigu

Nandini Nag, Somenath Chakrabarty

The effect of strong quantising magnetic field on low density stellar matter is investigated using Thomas-Fermi-Dirac (TFD) model. The Wigner-Seitz cell structure is assumed for the low density matter. The significant changes in the properties of such low density matter in presence of strong magnetic fields are discussed. It is seen that the decay time scale

N. Kaiser, J. L. Tonry, G. A. Luppino

We propose a new strategy for obtaining enhanced resolution (FWHM = 0.12 arcsec) deep optical images over a wide field of view. As is well known, this type of image quality can be obtained in principle simply by fast guiding on a small (D = 1.5m) telescope at a good site, but only for target objects which lie within a limited angular distance of a suitably b

Michel Fioc, Brigitte Rocca-Volmerange

We provide here the documentation of the new version of the spectral evolution model PEGASE. PEGASE computes synthetic spectra of galaxies in the UV to near-IR range from 0 to 20 Gyr, for a given stellar IMF and evolutionary scenario (star formation law, infall, galactic winds). The radiation emitted by stars from the main sequence to the pre-supernova or wh

C. Adami, M. P. Ulmer, F. Durret, R. C. Nichol

Our previous study of the faint end (R$\leq$21.5) of the galaxy luminosity function (GLF) was based on spectroscopic data in a small region near the Coma cluster center. In this previous study Adami et al. (1998) suggested, with moderate statistical significance, that the number of galaxies actually belonging to the cluster was much smaller than expected. Th

Martin Gremm

We consider an especially simple version of a thick domain wall in $AdS$ space and investigate how four-dimensional gravity arises in this context. The model we consider has the advantage, that the equivalent quantum mechanics problem can be stated in closed form. The potential in this Schrödinger equation suggests that there could be resonances in the spect

Alejandro Corichi, Daniel Sudarsky

New results pertaining to colored static black hole solutions to the Einstein-Yang-Mills equations are obtained. The isolated horizons framework is used to define the concept of Hamiltonian Horizon Mass of the black hole. An unexpected relation between the ADM and Horizon masses of the black hole solution with the ADM mass of the corresponding Bartnik-McKinn

Shiraz Minwalla, Mark Van Raamsdonk, Nathan Seiberg

We study the perturbative dynamics of noncommutative field theories on R^d, and find an intriguing mixing of the UV and the IR. High energies of virtual particles in loops produce non-analyticity at low momentum. Consequently, the low energy effective action is singular at zero momentum even when the original noncommutative field theory is massive. Some of t

Boris Berdnikov, Krishna Rajagopal

The QCD phase diagram may feature a critical end point at a temperature T and baryon chemical potential $μ$ which is accessible in heavy ion collisions. The universal long wavelength fluctuations which develop near this Ising critical point result in experimental signatures which can be used to find the critical point. The magnitude of the observed effects d

Marcus B. Pinto, Rudnei O. Ramos

The optimized linear $δ$-expansion is applied to multi-field $O(N_1) \times O(N_2)$ scalar theories at high temperatures. Using the imaginary time formalism the thermal masses are evaluated perturbatively up to order $δ^2$ which considers consistently all two-loop contributions. A variational procedure associated with the method generates nonperturbative res

M. P. Bellon

The relevance of the algebraic entropy in the study of birational discrete time dynamical systems highlights the need to relate it to other characteristics of these systems. In this letter, two complementary proofs are given that the foliation of the space by invariant curves implies that the algebraic entropy is zero.

Eduardo C. Marino, Marcello B. Silva Neto

We present an analytic expression for the finite temperature effective sublattice magnetization which would be detected by inelastic neutron scattering experiments performed on a two-dimensional square-lattice quantum Heisenberg antiferromagnets with short range Néel order. Our expression, which has no adjustable parameters, is able to reproduce both the qua

Erik M. Gregersen, Neal J. Evans, Diego Mardones, Philip C. Myers

We have observed HCO+ J=3-2 toward 16 Class I sources and 18 Class 0 sources, many of which were selected from Mardones et al. (1997). Eight sources have profiles significantly skewed to the blue relative to optically thin lines. We suggest six sources as new infall candidates. We find an equal &#34;blue excess&#34; among Class 0 and Class I sources after co

Jens Kujat, Robert J. Scherrer

A time variation in the Higgs vacuum expectation value alters the electron mass and thereby changes the ionization history of the universe. This change produces a measurable imprint on the pattern of cosmic microwave background (CMB) fluctuations. The nuclear masses and nuclear binding energies, as well as the Fermi coupling constant, are also altered, with

Donavan Hall, Z. Fisk, R. G. Goodrich

We have measured the magnetic field dependence of the paramagnetic to high temperature magnetically ordered phase transition TQ(H) in CeB6 from 2 to 30 T using cantilever magnetometry. It is found that the phase separation temperature continuously increases in field with an increasingly positive slope. In addition, we find that measurements in strong magneti

D. Lust, A. Miemiec

In this paper we investigate the form of calibrated M5-branes in the presence of a nonvanishing 3-form field H. We discuss the influence of the H-field on the deformation of supersymmetric n-cycles (in particular SLAG submanifolds in R^n). In addition we argue for a construction which relates calibrated M5-branes of different curved dimensions to each other.

W. Nahm, K. Wendland

We study the moduli space ${\cal M}$ of N=(4,4) superconformal field theories with central charge c=6. After a slight emendation of its global description we find the locations of various known models in the component of ${\cal M}$ associated to K3 surfaces. Among them are the Z_2 and Z_4 orbifold theories obtained from the torus component of ${\cal M}$. Her

M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee

We have measured the reaction p + d -> 3He + eta at a proton beam energy of 980 MeV, which is 88.5 MeV above threshold using the new ``germanium wall'' detector system. A missing--mass resolution of the detector system of 2.6% was achieved. The angular distribution of the meson is forward peaked. We found a total cross section of (573 +- 83(stat.) +- 69(syst

P. Taxil, E. Tugcu, J. -M. Virey

We analyze the effects of Scalar and Vector Leptoquarks on various observables in electron (positron) - proton deep inelastic scattering. In view of the future program of the HERA collider, with a high luminosity and also with polarization, we present the constraints that can be reached using this facility for several Leptoquark scenarios. We address the que

D. Tanasković, Z. Radović, L. Dobrosavljević-Grujić

The Ginzburg-Landau equations are derived from the microscopic theory for clean layered superconductors with $d_{x^2-y^2}$ pairing symmetry, including the Pauli paramagnetism effect. The upper critical field $H_{c2}$ parallel to the $c$ axis is calculated. A comparison with the experimental data for YBCO suggests that, relative to the orbital effect, the Pau

Oleg Andreev, Harald Dorn

We consider the ordinary and noncommutative Dirac-Born-Infeld theories within the open string sigma-model. First, we propose a renormalization scheme, hybrid point splitting regularization, that leads directly to the Seiberg-Witten description including their two-form. We also show how such a form appears within the standard renormalization scheme just by so

Jesper Sommer-Larsen, Alexandre Dolgov

We have performed TreeSPH simulations of disk galaxy formation in various warm dark matter (WDM) cosmologies. Our results indicate that for a range of WDM free-streaming masses, the disk galaxy formation angular momentum problem can be completely resolved by going to the WDM structure formation scenario, without having to invoke stellar feedback processes at

E. A. Pasyuk, R. L. Boudrie, P. A. M. Gram, C. L. Morris

We have measured cross sections for the $ (π^+,π^\pm p)$ reactions on ${\rm ^3H}$, ${\rm ^4He}$, ${\rm ^6Li}$ and ${\rm ^7Li}$ in quasi-free kinematics at incident pion beam energy 500 MeV. An enhancement of the $(π^+,π^- p)$ cross section in this kinematics is observed. If this is interpreted as due to quasi-free scattering from pre-existing $Δ$ components

Bela Szilagyi, Roberto Gomez, Nigel T. Bishop, Jeffrey Winicour

We investigate the numerical stability of Cauchy evolution of linearized gravitational theory in a 3-dimensional bounded domain. Criteria of robust stability are proposed, developed into a testbed and used to study various evolution-boundary algorithms. We construct a standard explicit finite difference code which solves the unconstrained linearized Einstein

Michael Schwamb, Hartmuth Arenhoevel

A model is developed for the hadronic interaction in the two-nucleon system above pion threshold which is based on meson, nucleon and $Δ$ degrees of freedom and which includes full meson retardation in the exchange operators. For technical reasons, the model allows maximal one meson to be present explicitly. Thus the Hilbert space contains besides $NN$ and $

Tomasz Brzezinski, Cezary Gonera, Piotr Kosinski, Pawel Maslanka

A relationship between the action-angle variables and the canonical transformation relating the rational Calogero-Moser system to the free one is discussed.

Parampreet Singh, Naresh Dadhich

By requiring the linear differential operator in Newton&#39;s law of motion to be self adjoint, we obtain the field equation for the linear theory, which is the classical electrodynamics. In the process, we are also led to a fundamental universal chiral relation between electric and magnetic monopoles which implies that the two are related. Thus there could

Nan-Jian Wu, M. Kamada, A. Natori, H. Yasunaga

We propose a method for implementation of a quantum computer using artificial molecules. The artificial molecule consists of two coupled quantum dots stacked along z direction and one single electron. One-qubit and two-qubit gates are constructed by one molecule and two coupled molecules, respectively.The ground state and the first excited state of the molec

Yan-Gang Miao, H. J. W. Mueller-Kirsten

The duality symmetries of various chiral boson actions are investigated using D=2 and D=6 space-time dimensions as examples. These actions involve the Siegel, Floreanini-Jackiw, Srivastava and Pasti-Sorokin-Tonin formulations. We discover that the Siegel, Floreanini-Jackiw and Pasti-Sorokin-Tonin actions have self-duality with respect to a common anti-dualiz

A. Cano, A. P. Levanyuk

Almost all normal-incommensurate phase transitions observed experimentally are continuous. We show that there is not any theoretical reason for this general behaviour in perfect crystals. A normal-incommensurate phase transition that is not too far from the mean-field tricritical point should be discontinuous and it is highly improbable that so far reported

Yun Chang Shin, Bong Soo Han, Myung Ki Cheoun, K. S Kim

A SU(2) effective lagrangian is extended to a $SU_{L}(3)\otimes SU_{R}(3)$ by including the vector and axial vector meson. With this effective lagrangian, electromagnetic form factors of charged pion and kaon are calculated. The pseudoscalar meson loops are taken into account. Good agreement with experimental data is obtained for those form factors. Decay wi

Konstantin G. Zloshchastiev

We study the properties of the topologically nontrivial doublet solution arisen in the biscalar theory with a fourth-power potential introducing an example of the spontaneous breaking of symmetry. We rule out the zero-brane (non-minimal point particle) action for this doublet as a particle with curvature. When quantizing it as the theory with higher derivati

Konstantin G. Zloshchastiev

The field-to-particle transition formalizm based on the effective zero-brane action approach is generalized for arbitrary multiscalar fields. As a fruitful example, by virtue of this method we derive the non-minimal particle action for the Jackiw-Teitelboim gravity at fixed gauge in the vicinity of the black hole solution as an instanton-dilaton doublet. Whe

Kriten J. Joshi, Cody P. Nave, Frederic A. Rasio

We study the dynamical evolution of globular clusters using our new 2-D Monte Carlo code, and we calculate the lifetimes of clusters in the Galactic environment. We include the effects of a mass spectrum, mass loss in the Galactic tidal field, and stellar evolution. We consider initial King models containing N = 10^5 - 3x10^5 stars, and follow the evolution

Darwin Chang, Otto C. W. Kong

We propose a scheme in which a pseudo-Dirac structure for three family of light neutrinos is generated naturally. An extended Higgs sector with a majoron is used for the generation of the leptonic number violating neutrino Majorana mass. The resultant neutrino mass matrix could easily fit all available experimental data. We discuss relevant constraints on th

K. D. Borne, H. Bushouse, R. A. Lucas, L. Colina

In a large sample of ULIRGs imaged with HST, we have identified a significant subsample that shows evidence for multiple mergers. The evidence is seen among two classes of ULIRGs: (1) those with multiple remnant nuclei in their core, sometimes accompanied by a complex system of tidal tails; and (2) those that are in fact dense groupings of interacting (soon-

Michele Vallisneri

For an inspiraling neutron-star/black-hole binary (NS/BH), we estimate the gravity-wave frequency f_td at the onset of NS tidal disruption. We model the NS as a tidally distorted, homogeneous, Newtonian ellipsoid on a circular, equatorial geodesic around a Kerr BH. We find that f_td depends strongly on the NS radius R, and estimate that LIGO-II (ca. 2006-200

P. Kanti, I. I. Kogan, K. A. Olive, M. Pospelov

We consider 5-dimensional cosmological solutions of a single brane. The correct cosmology on the brane, i.e., governed by the standard 4-dimensional Friedmann equation, and stable compactification of the extra dimension is guaranteed by the existence of a non-vanishing \hat{T}^5_5 which is proportional to the 4-dimensional trace of the energy-momentum tensor

Seth Lloyd, Benjamin Rahn, Charlene Ahn

Simulation of quantum systems that provide intrinsically fault-tolerant quantum computation is shown to preserve fault tolerance. Errors committed in the course of simulation are eliminated by the natural error-correcting features of the systems simulated. Two examples are explored, toric codes and non-abelian anyons. The latter is shown to provide universal

N. Linden, S. Popescu, B. Schumacher, M. Westmoreland

We consider the transformation of multisystem entangled states by local quantum operations and classical communication. We show that, for any reversible transformation, the relative entropy of entanglement for two parties must remain constant. This shows, for example, that it is not possible to convert 2N three party GHZ states into 3N singlets, even in an a

Sergio Albeverio, Shao-Ming Fei

We study quantum cloning machines (QCM) that act on an unknown N-level quantum state and make M copies. We give a formula for the maximum of the fidelity of cloning and exhibit the unitary transformations that realize this optimal fidelity. We also extend the results to treat the case of M copies from $N^\prime$ ($M>N^\prime$) identical N-level quantum syste

J. J. Halliwell

The most general description of the classical world is in terms of local densities (such as number, momentum, energy), and these typically evolve according to evolution equations of hydrodynamic form. To explain the emergent classicality of these variables from an underlying quantum theory, it is therefore necessary to show, firstly, that these variables exh

W. Tittel, H. Zbinden, N. Gisin

We present a setup for quantum secret sharing using pseudo-GHZ states based on energy-time entanglement. In opposition to true GHZ states, our states do not enable GHZ-type tests of nonlocality, however, they bare the same quantum correlations. The relatively high coincidence count rates found in our setup enable for the first time an application of a quantu

B. Ueberholz, S. Kuhr, D. Frese, D. Meschede

We have experimentally explored a novel possibility to study exoergic cold atomic collisions. Trapping of small countable atom numbers in a shallow magneto-optical trap and monitoring of their temporal dynamics allows us to directly observe isolated two-body atomic collisions and provides detailed information on loss statistics. A substantial fraction of suc

V. Dmitrašinović

We make a systematic examination of the role played by the restriction that the cross section in polarized coincidence electronuclear processes must be positive. The necessary formalism for unpolarized scattering structure functions is developed within two frameworks: (i) the response tensor method; and (ii) the Jacob-Wick method. Equivalence of the two meth

I. Vidaña, A. Polls, A. Ramos, Oe. Elgaroey

We present results from many-body calculations for β-stable neutron star matter with nucleonic and hyperonic degrees of freedom, employing the most recent parametrizations of the baryon-baryon interaction of the Nijmegen group. It is found that the only strange baryons emerging in β-stable matter up to total baryonic densities of 1.2 fm^{-3} are Σ^- and Λ. T

S. A. Dytman

The CEBAF Large Acceptnace Spectrometer (CLAS) has been taking production data since February, 1998. It takes data for many reactions simultaneously with moderate resolution. Data has been taken for a variety of conditions with polarized and unpolarized beam and target. Preliminary results of the initial experiments run by the CLAS collaboration are shown. T

Pavel Etingof, Shlomo Gelaki, Robert Guralnick, Jan Saxl

Recall that a finite group is called perfect if it does not have non-trivial 1-dimensional representations (over the field of complex numbers C). By analogy, let us say that a finite dimensional Hopf algebra H over C is perfect if any 1-dimensional H-module is trivial. Let us say that H is biperfect if both H and H^* are perfect. Note that, H is biperfect if

Jie Du, Leonard L. Scott

Two families of q-Schur algebras associated to Hecke algebras of type D are introduced, and related to a family used by Geck, Gruber and Hiss [10], [11]. We prove that the algebras in one family, called the q-Schur^{1.5} algebras, are integrally free, stable under base change, and are standardly stratified if the base field has odd characteristic. In the so-

Gregory G. Smith

We give a dimension bound on the irreducible components of the characteristic variety of a system of linear partial differential equations defined from a suitable filtration of the Weyl algebra $A_{n}(k)$. This generalizes an important consequence of the fact that a characteristic variety defined from the order filtration is involutive. More explicitly, we c

Stephen Sawin

The notion of 2-framed three-manifolds is defined. The category of 2-framed cobordisms is described, and used to define a 2-framed three-dimensional TQFT. Using skeletonization and special features of this category, a small set of data and relations is given that suffice to construct a 2-framed three-dimensional TQFT. These data and relations are expressed i

U. Goertz

Consider a PEL-Shimura variety associated to a unitary group that splits over an unramified extension of Q_p. Rapoport and Zink have defined a model of the Shimura variety over the ring of integers of the completion of the reflex field at a place lying over p, with parahoric level structures at p. We show that this model is flat, as conjectured by Rapoport a

V. N. Tolstoy, O. V. Ogievetsky, P. N. Pyatov, A. P. Isaev

We introduce a modified affine Hecke algebra $\h{H}^{+}_{qη}({l})$ ($\h{H}_{qη}({l})$) which depends on two deformation parameters $q$ and $η$. When the parameter $η$ is equal to zero the algebra $\h{H}_{qη=0}(l)$ coincides with the usual affine Hecke algebra $\h{H}_{q}(l)$ of type $A_{l-1}$, if the parameter q goes to 1 the algebra $\h{H}^{+}_{q=1η}(l)$ is

A. N. Dranishnikov

We show that a space with a finite asymptotic dimension is embeddable in a non-positively curved manifold. Then we prove that if a uniformly contractible manifold X is uniformly embeddable in $\R^n$ or non-positively curved n-dimensional simply connected manifold then $X\times\R^n$ is integrally hyperspherical. If a uniformly contractible manifold X of bound

Jie Du

We introduce the notion of a cellular system in order to deal with quasi-hereditary algebras. We shall prove that a necessary and sufficient condition for an algebra to be quasi-hereditary is the existence of a full divisible cellular system. As a further application, we prove that the existence of a full local cellular system is a sufficient condition for a

Vladimir Molotkov

A generalization of topos theory is proposed giving an abstract realization of such categories as, say, the categories of manifolds and of Grothendieck schemes on the one hand, and permitting one, on the other hand, a view on &#34;non-commutative&#34; or, more generally, &#34;universal&#34; algebraic geometry, which is alternative to already existing, and is

Masaki Kashiwara, Toshiyuki Tanisaki

We shall give a description of the intersection cohomology groups of the Schubert varieties in partial flag manifolds over symmetrizable Kac-Moody Lie algebras in terms of parabolic Kazhdan-Lusztig polynomials introduced by Deodhar.

Stephen Clark, Yuri Latushkin, Stephen J. Montgomery-Smith, Tim Randolph

In this paper the theory of evolution semigroups is developed and used to provide a framework to study the stability of general linear control systems. These include time-varying systems modeled with unbounded state-space operators acting on Banach spaces. This approach allows one to apply the classical theory of strongly continuous semigroups to time-varyin

V. Skalozub, V. Demchik

The electroweak phase transition in the magnetic and hypermagnetic fields is studied in the Standard Model on the base of investigation of symmetry behaviour within the consistent effective potential of the scalar and magnetic fields at finite temperature. It includes the one-loop and daisy diagram contributions. All discovered fundamental fermions and boson

Victor O. Rivelles

We discuss the formulation of the CGHS model in terms of a topological BF theory coupled to particles carrying non-Abelian charge.

H. Gopalkrishna Gadiyar

The analogy between General Relativity and monopole physics is pointed out and the presence of a 3-cocycle which corresponds to a source leads to discretization of field momentum. This is analogous to the same phenomena in monopole physics.

A. Nersessian, R. Manvelyan, H. J. W. Mueller-Kirsten

We consider a (2+1)-dimensional mechanical system with the Lagrangian linear in the torsion of a light-like curve. We give Hamiltonian formulation of this system and show that its mass and spin spectra are defined by one-dimensional nonrelativistic mechanics with a cubic potential. Consequently, this system possesses the properties typical of resonance-like

Bernard Knaepen

In this thesis, we compute within the field-antifield formalism the local BRST cohomology of various theories involving p-form gauge fields. A particular emphasis is put on the cohomology groups corresponding to the consistent local interactions, counterterms and candidate anomalies.

Rudolph C. Hwa, Qing-hui Zhang

The use of rapidity gaps is proposed as a measure of the spatial pattern of an event. When the event multiplicity is low, the gaps between neighboring particles carry far more information about an event than multiplicity spikes, which may occur very rarely. Two moments of the gap distrubiton are suggested for characterizing an event. The fluctuations of thos

D. Kazakov, G. Moultaka

We obtain general analytical forms for the solutions of the one-loop renormalization group equations in the top/bottom/$τ$ sector of the MSSM. These solutions are valid for any value of $\tan β$ as well as any non-universal initial conditions for the soft SUSY breaking parameters and non-unification of the Yukawa couplings. We establish analytically a generi

Uma Mahanta

In low energy phenomenology to avoid the strong constraints of proton decay it is usually assumed that light ($\approx $ 250 Gev) leptoquarks couple only to quark-lepton pairs and light diquarks couple only to quark pairs. In this work we show that the SM Higgs boson could induce a mixing between leptoquarks and diquarks through trilinear interaction terms w

Adrian Patrascioiu, Erhard Seiler

We comment on a recent paper by Allès et al.