August 1999 arXiv papers — page 21

Dagomir Kaszlikowski, Marek Zukowski

The Bell theorem for a pair of two-state systems in a singlet state is formulated for the entire range of measurement settings.

Erich Joos

In this contribution I give a brief introduction to the essential concepts and mechanisms of decoherence by the environment. The emphasis will be not so much on technical details but rather on conceptual issues and the impact on the interpretation problem of quantum theory.

J. Ye, D. W. Vernooy, H. J. Kimble

By integrating the techniques of laser cooling and trapping with those of cavity quantum electrodynamics (QED), single Cesium atoms have been trapped within the mode of a small, high finesse optical cavity in a regime of strong coupling. The observed lifetime for individual atoms trapped within the cavity mode is $τ\approx 28$ms, and is limited by fluctuatio

H. C. Rosu

The connection of unbroken SUSY quantum mechanics in its strictly isospectral form with the nonlinear Riccati superposition principle is pointed out

J. Main

In a recent paper Robicheaux and Shaw [Phys. Rev. A 58, 1043 (1998)] calculate the recurrence spectra of atoms in electric fields with non-vanishing angular momentum <L_z> not equal to 0. Features are observed at scaled actions ``an order of magnitude shorter than for any classical closed orbit of this system.&#39;&#39; We investigate the transition from zer

C. A. Bertulani, V. Yu. Ponomarev

A new class of giant resonances in nuclei, namely double giant resonances, is discussed. They are giant resonances built on top of other giant resonances. Investigation on their properties, together with similar studies on low-lying two-phonon states, should give an answer on how far the harmonic picture of boson-type excitations holds in the finite fermion

H. Müther, A. Polls

Various modern nucleon-nucleon (NN) potentials yield a very accurate fit to the nucleon-nucleon scattering phase shifts. The differences between these interactions in describing properties of nuclear matter are investigated. Various contributions to the total energy are evaluated employing the Hellmann - Feynman theorem. Special attention is paid to the two-

F. Finkel, A. Gonzalez-Lopez, M. A. Rodriguez

We develop a new way of writing the Lame Hamiltonian in Lie-algebraic form. This yields, in a natural way, an explicit formula for both the Lame polynomials and the classical non-meromorphic Lame functions in terms of Chebyshev polynomials and of a certain family of weakly orthogonal polynomials

R. M. Green, J. Losonczy

We compare the canonical basis for a generalized Temperley-Lieb algebra of type A or B with the Kazhdan-Lusztig basis for the corresponding Hecke algebra.

Wen-Li Yang, Yao-Zhong Zhang

We determine the exchange relations of the level-one q-vertex operators of the quantum affine superalgebra $U_q[\hat{gl(N|N)}]$. We study in details the level-one irreducible highest weight representations of $U_q[\hat{gl(2|2)}]$, and compute the characters and supercharacters associated with these irreducible modules.

Angelo Vistoli

Consider a primitive polynomial $f$ in two variables, thought of as a map from the affine plane to the affine line. We study the minimimal compactification of $f$; from our result one deduces in particular that if one of the fibers of $f$ has only one fiber at infinity, then all the fibers of $f$ have a simultaneous resolution of singularities at infinity. F

Travis Schedler

In the 1980&#39;s, Belavin and Drinfeld classified non-unitary solutions of the classical Yang-Baxter equation (CYBE) for simple Lie algebras. They proved that all such solutions fall into finitely many continuous families and introduced combinatorial objects to label these families, Belavin-Drinfeld triples. In 1993, Gerstenhaber, Giaquinto, and Schack atte

Bertfried Fauser, Heinz Dehnen

We propose a new method to generate the internal isospin degree of freedom by non-local bound states. This can be seen as motivated by Bargmann-Wigner like considerations, which originated from local spin coupling. However, our approach is not of purely group theoretical origin, but emerges from a geometrical model. The rotational part of the Lorentz group c

Jun S. Song

Using N=2 Landau-Ginzburg theories, we examine the recent conjectures relating the SU(3) WZW modular invariants, finite subgroups of SU(3) and Gorenstein singularities. All isolated three-dimensional Gorenstein singularities do not appear to be related to any known Landau-Ginzburg theories, but we present some curious observations which suggest that the SU(3

Robert Boehm, Holger Guenther, Carl Herrmann, Jan Louis

We study compactifications of type IIB supergravity on Calabi-Yau threefolds. The resulting low energy effective Lagrangian is displayed in the large volume limit and its symmetry properties - with specific emphasis on the SL(2,Z) - are discussed. The explicit map to type IIA string theory compactified on a mirror Calabi-Yau is derived. We argue that strong

Anupam Singh, Mark Srednicki

Starting from a Caldeira-Leggett model for the interaction of a system with an environment, Joichi, Matsumoto, and Yoshimura have reconsidered the derivation of the quantum Boltzmann equation. They find an extra term that accounts for the effects of virtual particles, and which drastically changes the results for relic densities of stable, weakly interacting

G. M. Shore

The formulae describing the radiative decays $η&#39;(η)\rta\c\c$ in QCD beyond the chiral limit are derived. The modifications of the conventional PCAC formulae due to the gluonic contribution to the axial anomaly in the flavour singlet channel are precisely described. The decay constants are found to satisfy a modified Dashen formula which generalises the W

Christophe Royon

Measurements of the diffractive structure function $F_2^{D(3)}(x_{\PO}, β, Q^2)$, describing the process $ep \to eXY$, are presented in the two kinematic regions $0.4 \leq Q^2 \leq 5$, ${\rm GeV}^2$, $0.001 \leq β\leq 0.65$, and $200 \leq β\leq 800 {\rm GeV^2}$, $0.4 \leq β\leq 0.9$, both with $\xpom < 0.05$, $M_{_Y} < 1.6 {\rm GeV}$ and $|t| < 1.0 {\rm GeV^

C. Royon

The QCD dipole picture allows to build an unified theoretical description -based on BFKL dynamics- of the total and diffractive nucleon structure functions measured at HERA. We use a four parameter fit to describe the 1994 H1 proton structure function $F_{2}$ data in the low x, moderate $Q^{2}$ range. The diffractive dissociation processes are discussed with

Wei-Shu Hou, Kwei-Chou Yang

Recent rare $B \to PP$, $PV$ decay data suggest that factorization holds well if, contrary to current fits, one has $\cosγ< 0$ where $γ\equiv {\rm arg}(V_{ub}^*)$. We update previous results with light cone sum rule form factors, which seem to work better. We then discuss various $B\to VV$ modes as well as the $K^{*} η$ modes. Finding the pattern of $ρ^+ω^0

J. J. M. Verbaarschot

The distribution of the low-lying QCD Dirac spectrum is analyzed by means of partial quenched chiral perturbation theory. We identify an energy scale below which the valence quark mass dependence of the QCD partition function is given by chiral Random Matrix Theory. This is the the domain where the low-energy QCD partition function is dominated by the fluctu

Walter Wilcox

The effects of an automated, tenth order in $κ$ subtraction scheme on the noise variance of various Wilson QCD disconnected matrix elements are examined. It is found that there is a dramatic reduction in the variance of the lattice point-split electromagnetic currents and that this reduction persists at small quark mass.

Valery Telnov

This report on Photon Colliders briefly reviews three main issues: physics motivation, possible parameters and technical feasibility, plans of works and international cooperation. New scheme of laser optics at the interaction region is described which can drastically (at least by one order) reduce the cost of the laser system.

P. N. Burrows

I present a summary of the experience with CCD-based vertex detectors at the SLD experiment at SLAC, and discuss their advantages for use at a future high-energy e+e- collider. The extensive R+D programme to improve further the vertexing capabilities of CCD detectors is also outlined.

I. Redondo

We present measurements on D*+- production cross sections in deep inelastic e+p scattering with 1<Q^2<600 GeV^2 and 0.02<y<0.7 in two restricted kinematic regions in p_t(D*) and eta(D*). The decay channels D*+ -> D0 pi+ with subsequent decay D0 -> K- pi+ or D0 -> K- pi+ pi+ pi- (+c.c) are used. The cross sections are extrapolated to the full kinematic region

J. Podolsky, J. B. Griffiths

Exact solutions for nonexpanding impulsive waves in a background with nonzero cosmological constant are constructed using a `cut and paste&#39; method. These solutions are presented using a unified approach which covers the cases of de Sitter, anti-de Sitter and Minkowski backgrounds. The metrics are presented in continuous and distributional forms, both of

Kengo Maeda, Takashi Torii, Makoto Narita

We calculate how much a first-quantized string is excited after crossing the inner horizon of charged Vaidya solutions, as a simple model of generic black holes. To quantize a string suitably, we first show that the metric is approximated by a {\it plane-wave} metric near the inner horizon when the surface gravity of the horizon $κ_I$ is small enough. Next,

Christian D. Lorenz, Raechelle May, Robert M. Ziff

Extensive Monte-Carlo simulations were performed in order to determine the precise values of the critical thresholds for site ($p^{hcp}_{c,S} = 0.199 255 5 \pm 0.000 001 0$) and bond ($p^{hcp}_{c,B} = 0.120 164 0 \pm 0.000 001 0$) percolation on the hcp lattice to compare with previous precise measuremens on the fcc lattice. Also, exact enumeration of the hc

J. Cerne, M. Grayson, D. C. Schmadel, G. S. Jenkins

Infrared (20-120 cm-1 and 900-1100 cm-1) Faraday rotation and circular dichroism are measured in high Tc superconductors using sensitive polarization modulation techniques. Optimally doped YBCO thin films are studied at temperatures down to 15 K and magnetic fields up to 8 T. At 1000 cm-1 the Hall conductivity varies strongly with temperature in contrast to

A. D. Bruce, N. B. Wilding

We develop a scaling theory for the finite-size critical behavior of the microcanonical entropy (density of states) of a system with a critically-divergent heat capacity. The link between the microcanonical entropy and the canonical energy distribution is exploited to establish the former, and corroborate its predicted scaling form, in the case of the 3d Isi

A. Ganshin, V. Grigor&#39;ev, V. Maidanov, N. Omelaenko

A pressure jump has been found at the onset of the dissolution of bcc inclusions in separated solid 3He-4He mixture if the crystal is overheated above a certain critical value. This effect can be explained in the framework of a multistage dissolution process model.

Bernardo A. Huberman, Dirk Helbing

As an example for the optimization of unstable flows, we present an economics-based method for deciding the optimal rates at which vehicles are allowed to enter a highway. It exploits the naturally occuring fluctuations of traffic flow and is flexible enough to adapt in real time to the transient flow characteristics of road traffic. Simulations based on rea

Shilpa Jain, David R. Nelson

The hydrodynamics of smectic films at an air-water interface is discussed, with particular focus on the viscous response of the film under flow normal to the layers. The corrections to the response functions of the smectic phase, arising from the coupling between the flow and the smectic order parameter, are calculated. The results for the effective viscosit

T. Mizokawa, D. I. Khomskii, G. A. Sawatzky

We have investigated possible spin and charge ordered states in 3d transition-metal oxides with small or negative charge-transfer energy, which can be regarded as self-doped Mott insulators, using Hartree-Fock calculations on d-p-type lattice models. It was found that an antiferromagnetic state with charge ordering in oxygen 2p orbitals is favored for relati

T. Mizokawa, C. Kim, Z. -X. Shen, A. Ino

We have performed an angle-resolved photoemission study on untwinned PrBa$_2$Cu$_3$O$_7$, which has low resistivity but does not show superconductivity. We have observed a dispersive feature with a band maximum around ($π$/2,$π$/2), indicating that this band is derived from the undoped CuO$_2$ plane. We have observed another dispersive band exhibiting one-di

M. Satake, K. Kobayashi, T. Mizokawa, A. Fujimori

We have studied the chemical potential shift in La$_{2-x}$Sr$_x$NiO$_4$ and the charge ordering transition in La$_{1.67}$Sr$_{0.33}$NiO$_4$ by photoemission spectroscopy. The result shows a large ($\sim$ 1 eV/hole) downward shift of the chemical potential with hole doping in the high-doping regime ($δ\gtrsim$ 0.33) while the shift is suppressed in the low-do

Beom Jun Kim, Petter Minnhagen

Two-dimensional Josephson junction arrays at zero temperature are investigated numerically within the resistively shunted junction (RSJ) model and the time-dependent Ginzburg-Landau (TDGL) model with global conservation of current implemented through the fluctuating twist boundary condition (FTBC). Fractional giant Shapiro steps are found for {\em both} the

G. Boffetta, M. Cencini, S. Espa, G. Querzoli

Lagrangian chaos is experimentally investigated in a convective flow by means of Particle Tracking Velocimetry. The Finite Size Lyapunov Exponent analysis is applied to quantify dispersion properties at different scales. In the range of parameters of the experiment, Lagrangian motion is found to be chaotic. Moreover, the Lyapunov depends on the Rayleigh numb

W. N. Brandt, A. Laor, Beverley J. Wills

Recent studies of QSOs with ROSAT suggest the existence of a significant population of Soft X-ray Weak QSOs (SXW QSOs) where the soft X-ray flux is ~ 10-30 times smaller than in typical QSOs. As a first step in a systematic study of these objects, we establish a well-defined sample of SXW QSOs which includes all alpha_ox<=-2 QSOs from the Boroson & Green (19

Gibor Basri, Eduardo Martin

PPl 15 is the first object to have been confirmed as a brown dwarf by the lithium test (in 1995), though its inferred mass was very close to the substellar limit. It is a member of the Pleiades open cluster. Its position in a cluster color-magnitude diagram suggested that it might be binary, and preliminary indications that it is a double-lined spectroscopic

G. Bono, V. Castellani, M. Marconi

Within the current uncertainties in the treatment of the coupling between pulsation and convection, limiting amplitude, nonlinear, convective models appear the only viable approach for providing theoretical predictions about the intrinsic properties of radial pulsators. In this paper we present the results of a comprehensive set of Cepheid models computed wi

Jerome A. Orosz, Richard A. Wade

We report additional photometric CCD observations of KPD 0422+5421, a binary with an orbital period of 2.16 hours which contains a subdwarf B star (sdB) and a white dwarf. There are two main results of this work. First, the light curve of KPD 0422+5421 contains two distinct periodic signals, the 2.16 hour ellipsoidal modulation discovered by Koen, Orosz, & W

W. B. Burton, Felix J. Lockman

We have measured the 21-cm line of Galactic HI over more than 50 square degrees in the direction of the Sagittarius dwarf spheroidal galaxy. The data show no evidence of HI associated with the dwarf spheroidal which might be consider analogous to the Magellanic Stream as it is associated in both position and velocity with the Large Magellanic Cloud. Nor do t

D. Breitschwerdt, V. Dogiel, H. J. V&#34;olk

One of the unsolved problems in cosmic ray (CR) physics is the small radial gradient of the gamma-ray intensity compared to the inferred CR source distribution in the Galactic disk. In diffusive CR propagation models the most natural explanation is very efficient spatial mixing due to MHD turbulence in the interstellar medium. However, even in the most favor

P. Saracco, S. D&#39;Odorico, A. Moorwood, A. Buzzoni

We present J and Ks band galaxy counts down to J=24 and Ks=22.5 obtained with the new infrared imager/spectrometer, SOFI, at the ESO New Technology Telescope. The co-addition of short, dithered, images led to a total exposure time of 256 and 624 minutes respectively, over an area of $\sim20$ arcmin$^2$ centered on the NTT Deep Field. The total number of sour

Tamas Budavari, Alex S. Szalay, Andrew J. Connolly, Istvan Csabai

We present a novel method capable of creating optimal eigenspectra from multicolor redshift surveys for photometric redshift estimation. Our iterative training algorithm modifies the templates to represent the photometric measurements better. We present a short description of our algorithm here. We show that the corrected templates give more precise photomet

Max Pettini, Charles C. Steidel, Kurt L. Adelberger, Mark Dickinson

We present an intermediate resolution, high S/N spectrum of the z = 2.7268 galaxy MS 1512-cB58, obtained with LRIS on the Keck I telescope and covering the rest frame far-UV from 1150 to 1930 A. Gravitational lensing by a foreground cluster boosts the flux from cB58 by a factor of about 30 and provides the opportunity for a first quantitative study of the ph

Kazuhiro Yamamoto, Hiroaki Nishioka, Yasushi Suto

We examine observational consequences of the cosmological light-cone effect on the power spectrum of the distribution of galaxies and quasars from upcoming redshift surveys. First we derive an expression for the power spectrum of cosmological objects in real space on a light cone, $P^{\rm LC}_{\rm R,lin}(k)$, which is exact in linear theory of density pertur

Alonso Botero, Benni Reznik

We propose a communication protocol exploiting correlations between two events with a definite time-ordering: a) the outcome of a {\em weak measurement} on a spin, and b) the outcome of a subsequent ordinary measurement on the spin. In our protocol, Alice, first generates a &#34;code&#34; by performing weak measurements on a sample of N spins. The sample is

Greg Kuperberg

The notion of a completely saturated packing [Fejes Toth, Kuperberg and Kuperberg, Highly saturated packings and reduced coverings, Monats. Math. 125 (1998) 127-145] is a sharper version of maximum density, and the analogous notion of a completely reduced covering is a sharper version of minimum density. We define two related notions: uniformly recurrent and

S. Bose, P. L. Knight, M. B. Plenio, V. Vedral

We show how the state of an atom trapped in a cavity can be teleported to a second atom trapped in a distant cavity simply by detecting photon decays from the cavities. This is a rare example of a decay mechanism playing a constructive role in quantum information processing. The scheme is comparatively easy to implement, requiring only the ability to trap a

D. V. Ramana Reddy, A. Sen, G. L. Johnston

We study the effects of time delayed linear and nonlinear feedbacks on the dynamics of a single Hopf bifurcation oscillator. Our numerical and analytic investigations reveal a host of complex temporal phenomena such as phase slips, frequency suppression, multiple periodic states and chaos. Such phenomena are frequently observed in the collective behavior of

Navot Israeli, Hyeong-Chai Jeong, Daniel Kandel, John D. Weeks

We study several one dimensional step flow models. Numerical simulations show that the slope of the profile exhibits scaling in all cases. We apply a scaling ansatz to the various step flow models and investigate their long time evolution. This evolution is described in terms of a continuous step density function, which scales in time according to D(x,t)=F(x

N. Tetradis

We examine some of the implications of the field-theoretical mechanism for the localization of gauge fields on hypersurfaces in higher-dimensional bulk space-time. This mechanism exploits the analogy between confinement and dual superconductivity. In the simplest case of a photon localized on a (2+1)-dimensional surface in a (3+1)-dimensional bulk, we argue

Leor Barack

We study analytically, via the Newman-Penrose formalism, the late time decay of scalar, electromagnetic, and gravitational perturbations outside a realistic rotating (Kerr) black hole. We find a power-law decay at timelike infinity, as well as at null infinity and along the event horizon (EH). For generic initial data we derive the power-law indices for all

Chiaki Kobayashi, Takuji Tsujimoto, Ken&#39;ichi Nomoto

We make a prediction of the cosmic supernova rate history as a composite of the supernova rates in spiral and elliptical galaxies. We include the metallicity effect on the evolution of Type Ia supernova (SN Ia) progenitors, and construct detailed models for the evolutions of spiral and elliptical galaxies in clusters and field to meet the latest observationa

K. G. Selivanov

Classical solutions generating tree form-factors are defined and constructed in various models.

JeongHyeong Park, Dae-Yup Song

Berry phase of simple harmonic oscillator is considered in a general representation. It is shown that, Berry phase which depends on the choice of representation can be defined under evolution of the half of period of the classical motions, as well as under evolution of the period. The Berry phases do {\em not} depend on the mass or angular frequency of the o

R. P. Malik, A. K. Mishra, G. Rajasekaran

We develop a $GL_{qp}(2)$ invariant differential calculus on a two-dimensional noncommutative quantum space. Here the co-ordinate space for the exterior quantum plane is spanned by the differentials that are commutative (bosonic) in nature.

Alex Clark

We introduce the group of exponents of a map of the reals into a metric space and give conditions under which this group embeds in the first Cech cohomology group of the closure of the image of the map. We show that this group generalizes the subgroup of the reals generated by the Fourier-Bohr exponents of an almost periodic orbit and that any minimal almost

Jack Morava

Recent work by physicists on gravity in two dimensions has a natural generalization to four dimensions, formulated in terms of an analogue of Segal&#39;s category [defined for the study of conformal field theory].

Bernard de Wit, Ivan Herger

We give a pedagogical introduction to certain aspects of supersymmetric field theories in anti-de Sitter space. Among them are the presence of masslike terms in massless wave equations, irreducible unitary representations and the phenomenon of multiplet shortening.

A. L. S. Angelis, J. Bartke, M. Yu. Bogolyubsky, S. N. Filippov

We present a phenomenological model which describes the formation of a Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and at the LHC, and its decay to non-strange baryons and Strangelets. We describe the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in an event-by-event mode, the very forward, baryon-rich

Christopher Beetle, Stephen Fairhurst

Boundary conditions defining a non-rotating isolated horizon are given in Einstein-Maxwell theory. A spacetime representing a black hole which itself is in equilibrium but whose exterior contains radiation admits such a horizon. Inspired by Hamiltonian mechanics, a (quasi-)local definition of isolated horizon mass is formulated. Although its definition does

Shahar Hod

The cosmic censorship hypothesis introduced by Penrose thirty years ago is still one of the most important open questions in {\it classical} general relativity. The main goal of this paper is to put forward the idea that cosmic censorship is intrinsically a {\it quantum} phenomena. We construct a gedanken experiment which seems to violate the cosmic censorsh

Zvika Marx, Ido Dagan, Eli Shamir

This paper addresses a novel task of detecting sub-topic correspondence in a pair of text fragments, enhancing common notions of text similarity. This task is addressed by coupling corresponding term subsets through bipartite clustering. The paper presents a cost-based clustering scheme and compares it with a bipartite version of the single-link method, prov

S. Das Sarma, P. Punyindu, Z. Toroczkai

We demonstrate, using well-established nonequilibrium growth models, that mound formation in the dynamical surface growth morphology does not necessarily imply a surface edge diffusion bias (the Schwoebel barrier) as has been almost universally accepted in the literature. We find mounded morphologies in several nonequilibrium growth models which incorporate

J. C. Flores

In references cond-mat/9907171 and cond-mat/9606206 (Phys.Rev.B.53, 4927 (1996)) by You-Quan Li and Bin Chen, was considered a mesoscopic LC circuit with charge discreteness. So, it was proposed a finite difference Schroedinger equation for the charge time behavior. In this comment, we generalize the corresponding mesoscopic Hamiltonian in order to taken int

T. Jujo, S. Koikegami, K. Yamada

We study the superconducting transition temperature and the electronic properties of the metallic phase of $κ$-type (BEDT-TTF)$_2$X which shows unconventional properties in experiments, on the basis of the third order perturbation theory for a simple effective Hubbard model of a nearly triangular lattice. Appropriate transition temperatures and $d_{x^2-y^2}$

T. Jujo, K. Yamada

The explanation of the anomalous behavior in $κ$-type (BEDT-TTF)$_2$X which was revealed by the nuclear magnetic resonance experiments is presented. We calculate the electronic properties by using the one-loop approximation for the superconducting fluctuation. The decrease of the density of states due to the large damping effect is obtained and the one-parti

Oleg Tchernyshyov, Leonid P. Pryadko

To study a possible effect of transverse fluctuations of a stripe in a 2D antiferromagnet on its charge dynamics, we identify elementary excitations of a weakly doped domain wall in the Hubbard model. Hartree-Fock numerics and analysis of fermion zero modes suggest that for U>=3t charged excitations are mobile holons, Q=1, S=0. Each holon resides on a kink i

Mitchell J. Feigenbaum, Itamar Procaccia, Benny Davidovich

We study the dynamics of &#34;finger&#34; formation in Laplacian growth without surface tension in a channel geometry (the Saffman-Taylor problem). Carefully determining the role of boundary geometry, we construct field equations of motion, these central to the analytic power we can here exercise. We consider an explicit analytic class of maps to the physica