October 2000 arXiv papers — page 2

Yi-Fang Wang

We propose here a large homogeneous calorimeter as the next generation neutrino detector for $ν$ factories and/or conventional $ν$ beams. The active media is chosen to be water for obvious economical reasons. The \v Cerenkov light produced in water is sufficient to have good energy resolution, and the pattern recognition is realized by a modular water tank s

M. Artuso, CLEO Collaboration

Using 13.7 fb^{-1} of data recorded by the CLEO detector at CESR, we investigate the spectrum of charmed baryons which decay into Lambda_c^+ pi^- pi^+ and are more massive than the Lambda_{c1} baryons. We find evidence for two new states: one is broad and has an invariant mass roughly 480 MeV above that of the Lambda_c^+; the other is narrow with an invarian

Jun-ichi Tanaka

The lifetimes of charmed mesons have been measured using 2.75fb$^{-1}$ of data collected with the Belle detector at KEKB. Each candidate is fully reconstructed to identify the flavor of the charmed meson. The lifetimes are measured to be $τ(D^0)=(414.8\pm3.8\pm3.4)$ fs, $τ(D^+)=(1040^{+23}_{-22}\pm18)$ fs and $τ(D_s^+)=(479^{+17}_{-16}{}^{+6}_{-8})$ fs, wher

Merced Montesinos, Jose David Vergara

In this paper it is implemented how to make compatible the boundary conditions and the gauge fixing conditions for complex general relativity written in terms of Ashtekar variables using the Henneaux-Teitelboim-Vergara approach. Moreover, it is found that at first order in the gauge parameters, the Hamiltonian action is (on shell) fully gauge-invariant under

S. Jhingan, N. Dadhich, P. S. Joshi

We analyse here the gravitational collapse of directed null radiation in a background with a constant potential such as one produced by a star system like galaxy in which the collapsing object is immersed. Both naked singularities and black holes are shown to be developing as the final outcome of the collapse. An interesting feature that emerges is that a pa

Takahiro Tanaka, T. P. Singh

Recently the energy emission from a naked singularity forming in spherical dust collapse has been investigated. This radiation is due to the particle creation in a curved spacetime. In this discussion, the central role is played by the mapping formula between the incoming and the outgoing null coordinates. For the self-similar model, this mapping formula has

Lawrence C. Paulson

A theory of recursive and corecursive definitions has been developed in higher-order logic (HOL) and mechanized using Isabelle. Least fixedpoints express inductive data types such as strict lists; greatest fixedpoints express coinductive data types, such as lazy lists. Well-founded recursion expresses recursive functions over inductive data types; corecursio

Lawrence C. Paulson

A logic for specification and verification is derived from the axioms of Zermelo-Fraenkel set theory. The proofs are performed using the proof assistant Isabelle. Isabelle is generic, supporting several different logics. Isabelle has the flexibility to adapt to variants of set theory. Its higher-order syntax supports the definition of new binding operators.

Lawrence C. Paulson

Simple type theory is formulated for use with the generic theorem prover Isabelle. This requires explicit type inference rules. There are function, product, and subset types, which may be empty. Descriptions (the eta-operator) introduce the Axiom of Choice. Higher-order logic is obtained through reflection between formulae and terms of type bool. Recursive t

Lawrence C. Paulson

Isabelle is a generic theorem prover, designed for interactive reasoning in a variety of formal theories. At present it provides useful proof procedures for Constructive Type Theory, various first-order logics, Zermelo-Fraenkel set theory, and higher-order logic. This survey of Isabelle serves as an introduction to the literature. It explains why generic the

Lawrence C. Paulson

Isabelle is an interactive theorem prover that supports a variety of logics. It represents rules as propositions (not as functions) and builds proofs by combining rules. These operations constitute a meta-logic (or `logical framework') in which the object-logics are formalized. Isabelle is now based on higher-order logic -- a precise and well-understood

Lawrence C. Paulson

An interactive theorem prover, Isabelle, is under development. In LCF, each inference rule is represented by one function for forwards proof and another (a tactic) for backwards proof. In Isabelle, each inference rule is represented by a Horn clause. Resolution gives both forwards and backwards proof, supporting a large class of logics. Isabelle has been use

Lawrence C. Paulson

Martin-Löf's Intuitionistic Theory of Types is becoming popular for formal reasoning about computer programs. To handle recursion schemes other than primitive recursion, a theory of well-founded relations is presented. Using primitive recursion over higher types, induction and recursion are formally derived for a large class of well-founded relations. In

Joseph O'Rourke

It has recently been established by Below, De Loera, and Richter-Gebert that finding a minimum size (or even just a small) triangulation of a convex polyhedron is NP-complete. Their 3SAT-reduction proof is discussed.

Erwan Jahier

A program execution monitor is a program that collects and abstracts information about program executions. The "collect" operator is a high level, general purpose primitive which lets users implement their own monitors. "Collect" is built on top of the Mercury trace. In previous work, we have demonstrated how this operator can be used to effi

Umberto Straccia

In fuzzy propositional logic, to a proposition a partial truth in [0,1] is assigned. It is well known that under certain circumstances, fuzzy logic collapses to classical logic. In this paper, we will show that under dual conditions, fuzzy logic collapses to four-valued (relevance) logic, where propositions have truth-value true, false, unknown, or contradic

Eric Goles, Michel Morvan, Ha Duong Phan

This paper is devoted to the study of the dynamics of a discrete system related to some self stabilizing protocol on a ring of processors.

M. Drndic, C. S. Lee, R. M. Westervelt

Three-dimensional (3D) micro-electromagnets were developed to control particle motion in magnetic field landscapes in vacuum near a chip. Multiple layers of micron-scale conductors separated by transparent insulators create particle containers with deep, symmetric and time-dependent potentials, suitable for integration in quantum circuits. Single and coupled

Yasufumi Yamashita, Kazuo Ueda

The ground-state properties of the spin-1 antiferromagnetic Heisenberg model on the corner-sharing tetrahedra, pyrochlore lattice, is investigated. By breaking up each spin into a pair of 1/2-spins, the problem is reduced to the equivalent one of the spin-1/2 tetrahedral network in analogy with the valence bond solid state in one dimension. The twofold degen

David L. Olmsted, Kedar Y. Hardikar, Rob Phillips

Atomistic computations of the Peierls stress in fcc metals are relatively scarce. By way of contrast, there are many more atomistic computations for bcc metals, as well as mixed discrete-continuum computations of the Peierls-Nabarro type for fcc metals. One of the reasons for this is the low Peierls stresses in fcc metals. Because atomistic computations of t

A. Rebei, J. de Pablo

A new mean-field type theory is proposed to study order-disorder transitions (ODT) in block copolymers. The theory applies to both the weak segregation (WS) and the strong segregation (SS) regimes. A new energy functional is proposed without appealing to the random phase approximation (RPA). We find new terms unaccounted for within RPA. We work out in detail

Daniel Sanchez-Portal, Emilio Artacho, Javier Junquera, Alberto Garcia

We have applied first-principles density-functional calculations to the study of the energetics, and the elastic and electronic properties of monatomic wires of Au, Cu, K, and Ca in linear and a planar-zigzag geometries. For Cu and Au wires, the zigzag distortion is favorable even when the linear wire is stretched, but this is not observed for K and Ca wires

Daniel Sanchez-Portal, Emilio Artacho, J. I. Pascual, J. Gomez-Herrero

The adsorption of C60 on Si(111) has been studied by means of first-principles density functional calculations. A 2x2 adatom surface reconstruction was used to simulate the terraces of the 7x7 reconstruction. The structure of several possible adsorption configurations was optimized using the ab initio atomic forces, finding good candidates for two different

Ping Sun, D. Schmeltzer, A. R. Bishop

We use the two cut-off renormalization group (RG) method to study the spin-Peierls model in one-dimension for the entire phonon frequency range. We integrate out the phonon and solve the effective Fermion system via mean field and RG methods. We make use of the symmetry that the Neel, dimerization, and spin current order parameters form an SU(2) triplet base

Chun-Min Chang, A. H. Castro Neto, A. R. Bishop

We study the problem of one-dimensional (1D) Luttinger liquids in the insulating Mott-Hubbard phase in the presence of acoustic phonons in the semiclassical limit. We show that solitonic excitations can propagate freely in the system and the energy required to produce a soliton is reduced by a polaronic effect. We find a critical value of the electron-phonon

Marc Ruhlander, C. M. Soukoulis

The probability distribution of the conductance p(g) of disordered 2d and 3d systems is calculated by transfer matrix techniques. As expected, p(g) is Gaussian for extended states while for localized states it is log-normal. We find that at the mobility edge p(g) is highly asymmetric and universal.

Y. Levinson, O. Entin-Wohlman, P. Wolfle

We consider pumping through a small quantum dot separated from the leads by two point contacts, whose conductances, $G_{1}$ and $G_{2}$, serve as pumping parameters. When the dot is pincched, we find that there is a "resonance line" in the parameter plane $\{G_{1}, G_{2}\}$ along which the Fermi energy in the leads aligns with the energy of the quasi

Dmitrii S. Golubev, Andrei D. Zaikin

An interplay between charge discreteness, coherent scattering and Coulomb interaction yields nontrivial effects in quantum transport. We derive a real time effective action and an equivalent quantum Langevin equation for an arbitrary coherent scatterer and evaluate its current-voltage characteristics in the presence of interactions. Within our model, at larg

F. Evers, B. M. Gammel

In Phys. Rev. Lett. 84, 1760 (2000) A.O.Gogolin has challenged the established point of view that Mott's law for the dynamical conductivity of a 1 dimensional insulator is correct. We present the result of a numerical solution of Berezinskii's recursion relations that demonstrate unambigously that the earlier solutions are indeed valid in contrast to

F. van Wijland

We show how to build up a systematic bosonic field-theory for a general reaction-diffusion process involving hard-core particles in arbitrary dimension. We criticize a recent approach proposed by Park, Kim and Park (Phys. Rev. E 62 (2000)). As a testbench for our method, we show how to recover the equivalence between asymmetric diffusion of excluding particl

Y. Rabin, S. Panyukov

We study the effects of thermal fluctuations on a small elastic ring. We derive analytical expressions for the correlation functions of the Euler angles, for the real space two--point correlation functions and for the probability distribution of writhe, as a function of the persistence lengths that determine the rigidity with respect to bending and twist. Fl

John J. Quinn, Arkadiusz Wojs, Kyung-Soo Yi, Izabela Szlufarska

The energy and photoluminescence (PL) spectra of a two-dimensional electron gas (2DEG) interacting with a valence-band hole are studied in the high-magnetic-field limit as a function of the filling factor nu and the separation $d$ between the electron and hole layers. For d smaller than the magnetic length lambda, the hole binds one or more electrons to form

Minoru Takahashi

Thermodynamic Bethe ansatz equations for XXZ model at $|Δ|\ge 1$ is simplified to an integral equation which has one unknown function. This equation is analytically continued to $|Δ|<1$.

Boyu Hou, Dantao Peng, Ruihong Yue

In this paper we derive out the exact solution of the SU(n) Hubbard model through the coordinate and the algebraic Bethe ansatz methods. The energy spectrum and the Bethe ansatz equations are obtained. Furthermore, we analysis the ground state and give out the exact analytic solution of the model.

Giulia Iori, Vassilis Koulovassilopoulos

We study the consumption behaviour of an asymmetric network of heterogeneous agents in the framework of discrete choice models with stochastic decision rules. We assume that the interactions among agents are uniquely specified by their ``social distance&#39;&#39; and consumption is driven by peering, distinction and aspiration effects. The utility of each ag

M. B. Walker

This article develops a Fermi-liquid theory for superconductors with anisotropic Fermi surfaces, Fermi-liquid interactions, and energy gaps. For d-wave superconductors, the Fermi-liquid interaction effects are found to be classifiable into strong and negligible renormalizaton effects, for symmetric and antisymmetric combinations of the energies of $k\uparrow

M. Sako, S. M. Kahn, E. Behar, J. S. Kaastra

The luminous infrared-loud quasar IRAS 13349+2438 was observed with the XMM-Newton Observatory as part of the Performance Verification program. The spectrum obtained by the Reflection Grating Spectrometer (RGS) exhibits broad (v ~ 1400 km/s FWHM) absorption lines from highly ionized elements including hydrogen- and helium-like carbon, nitrogen, oxygen, and n

J. Cottam, S. M. Kahn, A. C. Brinkman, J. W. den Herder

We present initial results from observations of the low-mass X-ray binary EXO 0748-67 with the Reflection Grating Spectrometer on board the XMM-Newton Observatory. The spectra exhibit discrete structure due to absorption and emission from ionized neon, oxygen, and nitrogen. We use the quantitative constraints imposed by the spectral features to develop an em

J. R. Peterson, F. B. S. Paerels, J. S. Kaastra, M. Arnaud

We present detailed spatially-resolved spectroscopy results of the observation of Abell 1835 using the European Photon Imaging Cameras (EPIC) and the Reflection Grating Spectrometers (RGS) on the XMM-Newton observatory. Abell 1835 is a luminous ($10^{46}$ ergs ${s}^{-1}$), medium redshift ($z=0.2523$), X-ray emitting cluster of galaxies. The observations sup

Keivan G. Stassun, Robert D. Mathieu, Frederick J. Vrba, Tsevi Mazeh

We use mid-IR (primarily 10 $μ$m) photometry as a diagnostic for the presence of disks with inner cavities among 32 pre-main sequence stars in Orion and Taurus-Auriga for which rotation periods are known and which do not show evidence for inner disks at near-IR wavelengths. Disks with inner cavities are predicted by magnetic disk-locking models that seek to

Renyue Cen, Greg L. Bryan

Hydrodynamic simulations of Lyman alpha clouds based on ab inito cosmological models have produced results that are in broad agreement with observations. However, further analyses have revealed that, with progressively higher numerical resolution, the median or cutoff line width of the simulated Lyman alpha clouds (i.e. the Doppler parameter) appears to conv

N. Mirabal, J. P. Halpern

In the error box of 3EG J1835+5918, the brightest as-yet unidentified EGRET source at intermediate Galactic latitude, we find a weak, ultrasoft X-ray source at energies E < 0.3 keV in the ROSAT All-Sky Survey. Deep optical imaging at the location of this source, as pinpointed by an observation with the ROSAT HRI, reveals a blank field to a limit of V > 25.2.

P. Massey, K. DeGioia-Eastwood, E. Waterhouse

Here we examine 12 Galactic clusters and OB associations containing Wolf-Rayet stars (W-Rs) and/or Luminous Blue Variables (LBVs), in order to assess the progentor masses of these evolved massive stars. We find that in the Milky Way, early-type WN stars evolve from stars with masses as low as 20Mo. Some early-type WN stars are found in clusters with very hig

T. Abu-Zayyad, K. Belov, D. J. Bird, J. Boyer

We study the spectrum and average mass composition of cosmic rays with primary energies between 10^{17} eV and 10^{18} eV using a hybrid detector consisting of the High Resolution Fly&#39;s Eye (HiRes) prototype and the MIA muon array. Measurements have been made of the change in the depth of shower maximum as a function of energy. A complete Monte Carlo sim

G. Brunetti, G. Setti

In this talk we briefly review the inverse Compton (IC) scattering of nuclear photons in the lobes of radio galaxies and quasars. We concentrate on the possibility to test this model with the Chandra observatory and to constrain the electron energy distribution by measuring the X-ray fluxes produced by this effect. We also discuss the evidence for IC scatter

E. Ros, J. C. Guirado, J. M. Marcaide, M. A. Perez-Torres

We present wide-field images of the quadruple gravitational lenses B1422+231 and MGJ0414+0534 obtained from global Very Long Baseline Interferometry (VLBI) observations at 8.4 GHz on 23 November 1997. We present also a lens model for MGJ0414+0534, which reproduces the core positions and flux densities of the VLBI images, combining a singular isothermal ellip

Th. Boller, M. Gliozzi, G. Griffiths, S. Sembay

We report on the XMM-Newton observations of the BL Lac object MS 0737.9+7441 during the performance verification phase. A simple power-law fit provides an adequate description of the integrated spectrum in the 0.2-10 keV energy band. The photon index is slightly steeper in the EPIC pn data with 2.38+-0.01 compared to the EPIC MOS data (2.28+-0.01). The diffe

Yehuda Hoffman

The uncovering of the large-scale structure that is hidden in the Zone of Avoidance is essential to our quest for the understanding of the dynamics of the nearby universe. Dedicated and sophisticated observations of the Zone of Avoidance have to be matched by equally sophisticated theoretical tools for the reconstruction of the large-scale structure from spa

Henry E. Kandrup

This paper explores the phenomenon of energy relaxation for stars in a galaxy embedded in a high density environment that is subjected continually to perturbations reflecting the presence of other nearby galaxies and/or incoherent internal pulsations. The analysis is similar to earlier analyses of energy relaxation induced by binary encounters between nearby

M. A. Barstow, Howard E. Bond, M. R. Burleigh, J. B. Holberg

We present initial results from a Hubble Space Telescope ultraviolet imaging survey of stars known to have hot white-dwarf companions which are unresolved from the ground. The hot companions, discovered through their EUV or UV emission, are hidden by the overwhelming brightnesses of the primary stars at visible wavelengths. Out of 17 targets observed, we hav

B. V. Vasiliev

The equilibrium of dense plasma in a gravity field and problem of a gravity-induced electric polarization in this matter are discussed. The calculation for metals performed before shows that both - the gravity-induced compressive strain and the gravity-induced electric field - are inversely proportional to their Young moduli. The calculation for high dense p

Mark Cropper, Silvia Zane, Gavin Ramsay, Frank Haberl

We model the spin pulse intensity and hardness ratio profiles of the isolated neutron star RXJ0720.4--3125 using XMM-Newton data. The observed variation is approximately sinusoidal with a peak-to-peak amplitude of 15%, and the hardness ratio is softest slightly before flux maximum. By using polar cap models we are able to derive maximum polar cap sizes and a

Charles Hellaby

We propose a method of testing source evolution theories that is independent of the effects of inhomogeneity, and thus complementary to other studies of evolution. It is suitable for large scale sky surveys, and the new generation of large telescopes. In an earlier paper it was shown that basic cosmological observations - luminosity versus redshift, area dis

J. Vernet, R. A. E. Fosbury, M. Villar-Martin, M. H. Cohen

In classifying the ensemble of powerful extragalactic radio sources, considerable evidence has accumulated that radio galaxies and quasars are orientation-dependent manifestations of the same parent population: massive spheroidal galaxies containing correspondingly massive black holes. [...] In this study, we exploit the opportunity to eliminate the quasar g

Karim A. Malik, D. Wands, D. H. Lyth, A. R. Liddle

We discuss the evolution of linear perturbations about a Friedmann-Robertson-Walker background metric, using only the local conservation of energy-momentum. We show that on sufficiently large scales the curvature perturbation on spatial hypersurfaces of uniform-density is constant when the non-adiabatic pressure perturbation is negligible. We clarify the con

Dimitri Alexei Gadotti

We have done a robust statistical study of the behaviour of color profiles for 257 Sbc galaxies, having determined (B-V) and (U-B) color gradients, as well as color indices of bulges and disks separately. Applying a bidimensional decomposition technique to model the brightness profiles of bulges and disks, we obtained characteristic structural parameters for

A. Chakraborty, D. K. Ojha, B. G. Anandarao, T. N. Rengarajan

Near-infrared photometry and narrow/broad-band imaging of the massive and luminous young stellar object IRAS 05361+3539 are presented. Imaging observations were made at Mt. Abu while the photometric data were taken from the 2MASS. From the color-color and color-magnitude diagrams, we identified several sources of faint Class II type and about six Class I typ

R. Morganti, T. A. Oosterloo, C. N. Tadhunter, G. van Moorsel

A search for HI absorption has been made in 23 radio galaxies using the ATCA, the VLA and the WSRT. In five galaxies HI absorption was detected. We investigate how the detection rate is distributed among galaxies with different radio and optical properties. Among the Fanaroff-Riley (FR) type I radio galaxies, only one object (10% of total) was detected. The

J. Rodriguez, P. Varniere, M. Tagger, Ph. Durouchoux

The Accretion Ejection Instability (hereafter AEI), has been proposed to explain, the energy and angular momentum transport from the innermost parts of accretion disks in the X-Ray Binaries (XB), (permitting thus the accretion), toward a coronal medium, which is thought to be the base of jets (Tagger & Pellat, 1999; Tagger 1999, Varnière et al., 2000; Corbel

M. Signore, D. Puy

These lecture notes intend to form a short pedagogical introduction to the use of typical type Ia-Supernovae (hereafter SNIa) as standard candles to determine the energy density of the universe. Problems of principle for taking SNIa as cosmological probes are pointed out, and new attempts at solving them are indicated including the empirical width-luminosity

Martin G. Haehnelt, Piero Madau, Rolf P. Kudritzki, Francesco Haardt

We discuss implications of a stellar-dominated UV background at high redshifts. The composite spectrum of 29 LBGs evaluated by Steidel etal (2000) at <z>=3.4 can be well fit by a stellar population with ongoing star formation, a Salpeter initial mass function, modest or negligible dust reddening, and no intrinsic HI photoelectric absorption. Fading starburst

Winfried Zimdahl, Alexander B. Balakin

We establish a general thermodynamic scheme for cosmic fluids with internal self-interactions and discuss equilibrium and non-equilibrium aspects of such systems in connection with (generalized) symmetry properties of the cosmological dynamics. As an example we construct an exactly solvable gas dynamical model of a ``deflationary&#39;&#39; transition from an

Michael Feast

Four examples are given of problems that arise in the study of emission-line stars, each of which deserves further quantitative study. (1) Archival slit spectra of ηCar show that epochs of low excitation have occurred regularly in the 2020 day period of Damineli et al. since at least 1948. They last about 10 percent of the period. Earlier slit spectra (1899

Lynne A. Hillenbrand, John M. Carpenter, Eric D. Feigelson

General properties of the Orion star-forming region are discussed, with a focus on the dense Orion Nebula Cluster (ONC). This cluster contains between 2500 and 4500 objects located within a few parsecs of the eponymous Trapezium stars. Its members are aged <1 to a few Myr and encompass the full spectrum of stellar masses <50 Msun, as well as brown dwarfs det

Tomek Plewa, Ewald Mueller

Implementation details and test cases of a newly developed hydrodynamic code, AMRA, are presented. The numerical scheme exploits the adaptive mesh refinement technique coupled to modern high-resolution schemes which are suitable for relativistic and non-relativistic flows. Various physical processes are incorporated using the operator splitting approach, and

R. J. Protheroe, A. Mücke

We discuss the various contributions to the jet luminosity in proton blazar models of active galactic nuclei and describe a method of estimating the jet luminosity from the observed spectral energy distribution (SED) and the fitted model parameters. We apply this to a synchrotron proton blazar (SPB) model for Markarian 501.

Joseph Silk

Galaxy disk formation must incorporate the multiphase nature of the interstellar medium. The resulting two-phase structure is generated and maintained by gravitational instability and supernova energy input, which yield a source of turbulent viscosity that is able to effectively compete in the protodisk phase with early angular momentum loss of the baryonic

Timothy R. Bedding

Asteroseismology involves using the resonant frequencies of a star to infer details about its internal structure and evolutionary state. Oscillation frequencies are most useful when accompanied by accurate measurements of the more traditional stellar parameters such as luminosity and effective temperature. The Hipparcos catalogue provides luminosities with p

D. Turnshek, S. Rao, W. Lane, E. Monier

Some results from an imaging program to identify low-redshift (0.09<z<1.63) damped Lyman-alpha (DLA) galaxies are presented. The standard paradigm that was widely accepted a decade ago, that DLA galaxies are the progenitors of luminous disk galaxies, is now being seriously challenged. The indisputable conclusion from imaging studies at low redshift is that t

Nadav Drukker, David J. Gross

We propose that the expectation value of a circular BPS-Wilson loop in N=4 SUSYM can be calculated exactly, to all orders in a 1/N expansion and to all orders in g^2 N. Using the AdS/CFT duality, this result yields a prediction of the value of the string amplitude with a circular boundary to all orders in alpha&#39; and to all orders in g_s. We then compare

Katrin Becker, Melanie Becker

We consider compactifications of ${\cal M}$-theory to four-dimensional Minkowski space on seven-dimensional non-compact manifolds. These compactifications include a warp factor which is non-constant due to the presence of sources coming from fivebranes wrapping two-dimensional submanifolds of the internal seven-dimensional space. We derive the expression for

R. Shyam, G. Penner, U. Mosel

We investigate the pp --> p Lambda K+ and pp --> p Sigma0 K+ reactions at beam energies near their thresholds within an effective Lagrangian model, where the strangeness production proceeds via the excitation of N*(1650), N*(1710), and N*(1720) baryonic resonances. It is found that the $N^*$(1650) resonance dominates both these reactions at near threshold en

Subhash Kak

Quantum computing algorithms require that the quantum register be initially present in a superposition state. To achieve this, we consider the practical problem of creating a coherent superposition state of several qubits. Owing to considerations of quantum statistics, this requires that the entropy of the system go down. This, in turn, has two practical imp

Mikhail V. Medvedev, George Rybicki

We investigate the structure of self-gravitating polytropic stellar systems. We present a method which allows to obtain approximate analytical solutions, $ψ_{n+ε}({\bf x})$, of the nonlinear Poisson equation with the polytropic index $n+ε$, given the solution $ψ_n({\bf x})$ with the polytropic index n, for any positive or negative $ε$ such that $|ε|\ll1$. Ap

R. Jackiw

In this paper, particle physics concepts are blended into a field theory for macroscopic phenomena: Fluid mechanics is enhanced by anticommuting Grassmann variables to describe vorticity, while an additional interaction for the Grassmann variables leads to supersymmetric fluid mechanics.

Valentina S. U. Fazio, Francesca Nannelli, Lachezar Komitov

The anchoring of the nematic liquid crystal N-(p-methoxybenzylidene)-p-butylaniline (MBBA) on Langmuir-Blodgett monolayers of fatty acids (COOHC$_{n}$H$_{2n+1}$) was studied as a function of the length of the fatty acid alkyl chains, $n$ ($n = 15, 17, 19, 21$). The monolayers were deposited onto ITO-coated glass plates which were used to assemble sandwich ce

M. Blaauboer, G. Kurizki, B. A. Malomed

We predict the existence of a new type of spatiotemporal solitons (&#34;light bullets&#34;) in two-dimensional self-induced-transparency media with refractive index modulation in the direction transverse to that of pulse propagation. These self-localized guided modes are found in an approximate analytical form, their existence and stability being confirmed b

CLEO Collaboration, T. E. Coan

We have measured the CP asymmetry A_CP = [BF(b -> s gamma) - BF(bbar -> sbar gamma)]/ [BF(b -> s gamma) + BF(bbar -> sbar gamma)] to be A_CP = (-0.079 +/- 0.108 +/- 0.022)(1.0 +/- 0.030), implying that, at 90% confidence level, A_CP lies between -0.27 and +0.10. These limits rule out some extreme non-Standard Model predictions, but are consistent with most,

John J. Bialek, August E. Evrard, Joseph J. Mohr

The failure of purely gravitational models of X-ray cluster formation to reproduce basic observed properties of the local cluster population suggests the need for one or more additional physical processes operating on the intracluster medium (ICM). We present results from 84 moderate resolution gas dynamic simulations designed to systematically investigate t

Jeffrey A. Appel

After a brief history of heavy quarks, I will discuss charm, bottom, and top quarks in turn. For each one, I discuss its first observation, and then what we have learned about production, hadronization, and decays - and what these have taught us about the underlying physics. I will also point out remaining open issues. For this series of lectures, the charm

MILC Collaboration, C. Bernard, T. Burch, T. A. DeGrand

The separation of a heavy quark and antiquark pair leads to the formation of a tube of flux, or &#34;string&#34;, which should break in the presence of light quark-antiquark pairs. This expected zero-temperature phenomenon has proven elusive in simulations of lattice QCD. In an extension of work reported last year we present clear evidence for string breakin

J. Podolsky, J. B. Griffiths

A class of exact solutions of Einstein&#39;s equations is analysed which describes uniformly accelerating charged black holes in an asymptotically de Sitter universe. This is a generalisation of the C-metric which includes a cosmological constant. The physical interpretation of the solutions is facilitated by the introduction of a new coordinate system for d

Daniel Dantchev, Joseph Rudnick

We study the behavior of systems in which the interaction contains a long-range component that does not dominate the critical behavior. Such a component is exemplified by the van der Waals force between molecules in a simple liquid-vapor system. In the context of the mean spherical model with periodic boundary conditions we are able to identify, for temperat

Philippe Grangier, Frédéric Grosshans

We discuss the criteria for teleporting coherent states from simple considerations about information exchange during the teleportation process.

Nuno M. Romão

The quantisation of the reduced first-order dynamics of the nonrelativistic model for Chern-Simons vortices introduced by Manton is studied on a sphere of given radius. We perform geometric quantisation on the moduli space of static solutions, using a Kaehler polarisation, to construct the quantum Hilbert space. Its dimension is related to the volume of the

Luc Blanchet, Christophe Salomon, Pierre Teyssandier, Peter Wolf

This paper is motivated by the current development of several space missions (e.g. ACES on International Space Station) that will fly on Earth orbit laser cooled atomic clocks, providing a time-keeping accuracy of the order of 5~10^{-17} in fractional frequency. We show that to such accuracy, the theory of frequency transfer between Earth and Space must be e

David Petrosyan, Gershon Kurizki

We consider a photonic crystal (PC) doped with four-level atoms whose intermediate transition is coupled near-resonantly with a photonic band-gap edge. We show that two photons, each coupled to a different atomic transition in such atoms, can manifest strong phase or amplitude correlations: One photon can induce a large phase shift on the other photon or tri

Otto Nachtmann, Timo Paulus

We examine diffractive proton-proton scattering. Using a functional integral approach we derive the scattering amplitudes, which are governed by the expectation value of lightlike Wegner-Wilson loops. This expectation value is then evaluated using a cumulant expansion and the model of the stochastic vacuum. From the scattering amplitudes we calculate total a

F. Di Renzo, L. Scorzato

We discuss the inclusion of fermionic loops contributions in Numerical Stochastic Perturbation Theory for Lattice Gauge Theories. We show how the algorithm implementation is in principle straightforward and report on the status of the project.

K. Gallmeister, B. Kämpfer, O. P. Pavlenko, C. Gale

A unique parametrization of secondary (thermal) dilepton yields in heavy-ion experiments at CERN-SPS is proposed. This parametrization resembles a thermal $q \bar q$ annihilation rate. This is inspired by the observation that lepton pair production rates are quantitatively similar, whether expressed in a hadronic or partonic basis. Adding the thermal yield a

Masaki Kashiwara

We study the properties of level zero modules over quantized affine algebras. The proof of the conjecture on the cyclicity of tensor products by Akasaka and the present author is given. Several properties of modules generated by extremal vectors are proved. The weights of a module generated by an extremal vector are contained in the convex hull of the Weyl g

Kiyoshi Higashijima, Tetsuji Kimura, Muneto Nitta, Makoto Tsuzuki

We investigate non-perturbative structures of the two-dimensional N=2 supersymmetric nonlinear sigma model on the quadric surface Q^{n-2}(C) = SO(n)/SO(n-2)xU(1), which is a Hermitian symmetric space, and therefore Kahler, by using the auxiliary field and large-n methods. This model contains two kinds of non-perturbatively stable vacua; one of them is the sa

Nikolai Uraltsev

Achievements in the heavy quark theory over the last decade are reviewed, with the main emphasis put on dynamical methods which quantify nonperturbative effects via application of the Operator Product Expansion. These include the total weak decay rates of heavy flavor hadrons and nonperturbative corrections to heavy quark sum rules. Two new exact superconver

P. Benaglia, Gustavo E. Romero, I. R. Stevens, Diego F. Torres

We discuss the possibility that the stellar system Cyg OB2 No.5 can be a gamma-ray source in the light of recent EGRET and radio data. This system is formed by an O7 Ia + Ofpe/WN9 contact binary. A third star, probably a B0 V star also associated with the system, is located at $\sim 1700$ AU from the primary. We estimate the expected gamma-ray luminosity fro

Osmi Vilhu, Juri Poutanen, Petter Nikula, Jukka Nevalainen

The Rossi X-ray Timing Explorer data of GRS 1915+105 from several observing periods are modeled with a thermal Comptonization model. Best-fit models indicate that there is a strong correlation between the inner disk temperature and the disk luminosity. The hard Comptonized luminosity does not depend significantly on the total luminosity. The spectral hardnes

M. Salle, J. Smit, J. C. Vink

We describe a Hartree ensemble method to approximately solve the Heisenberg equations for the ϕ^4 model in 1+1 dimensions. We compute the energies and number densities of the quantum particles described by the ϕfield and find that the particles initially thermalize with a Bose-Einstein distribution for the particle density. Gradually, however, the distributi

W. Y. Hwang, D. Ahn, S. W. Hwang

We give a (remote) quantum gambling scheme that makes use of the fact that quantum nonorthogonal states cannot be distinguished with certainty. In the proposed scheme, two participants Alice and Bob can be regarded as playing a game of making guesses on identities of quantum states that are in one of two given nonorthogonal states: if Bob makes a correct (an

Yoshiaki Sofue, Vera Rubin

Rotation curves of spiral galaxies are the major tool for determining the distribution of mass in spiral galaxies. They provide fundamental information for understanding the dynamics, evolution and formation of spiral galaxies. We describe various methods to derive rotation curves, and review the results obtained. We discuss the basic characteristics of obse

Alex Brodsky, Nicholas Pippenger

The 2-way quantum finite automaton introduced by Kondacs and Watrous can accept non-regular languages with bounded error in polynomial time. If we restrict the head of the automaton to moving classically and to moving only in one direction, the acceptance power of this 1-way quantum finite automaton is reduced to a proper subset of the regular languages. In

Enrico Brambilla, Alessandra Gatti, Patrick Navez, Luigi A. Lugiato

We show that spatial entanglement of two twin images obtained by parametric down-conversion is complete, i.e. concerns both amplitude and phase. This is realised through a homodyne detection of these images which allows for measurement of the field quadrature components. EPR correlations are shown to exist between symmetrical pixels of the two images. The be