December 2000 arXiv papers — page 6

C. R. Allton

The lattice technique of studying the strong interaction of matter is used to obtain predictions of the hadronic spectrum. These simulations were performed by the UKQCD collaboration using full (unquenched) QCD. Details of the results, a comparison with quenched data, and novel methods of extracting spectral properties are described.

Vivek Jain

This paper presents the latest results from experiment E787, at Brookhaven National Laboratory, on K+ -> pi nu/nubar and radiative K+ decays. The result for K+ -> pi nu/nubar uses data collected in runs taken during 1995, 1996 and 1997. In addition, we discuss plans for future measurements of K+ -> pi nu/nubar.

Franz Muheim

We present the status of the LHCb experiment which will make precision measurements of CP violation in $B$ meson decays. The motivation for the experiment and an overview of the detector design are given. The vertex detector, ring imaging Cherenkov counter, calorimeters, and trigger systems are discussed in detail. We also present the expected physics perfor

Franz Muheim

The 64-channel Multianode Photo Multiplier has been evaluated as a possible choice for the photo detectors of the LHCb Ring Imaging Cherenkov detector.

J. Damet, P. Eerola, A. Manara, S. E. M. Nooij

The observation potential of the decay B+ -> K+K+pi- with the ATLAS detector at LHC is described in this paper. In the Standard Model this decay mode is highly suppressed, while in models beyond the Standard Model it could be significantly enhanced. To improve the selection of the K+K+pi- final state, a charged hadron identification using Time-over-Threshold

Z. G. Zhao

We report the preliminary R values for all the 85 energy points scanned in the energy region of 2-5 GeV with the upgraded Beijing Spectrometer (BESII) at Beijing Electron Positron Collider (BEPC). Preliminary results from the J/psi data collected with both BESI and BESII are presented. Measurements of the branching fraction of the psi(2S) decays and the psi(

A. Tartaglia

New techniques to evaluate the clock effect using light are described. These are based on the flatness of the cylindrical surface containing the world lines of the rays constrained to move on circular trajectories about a spinning mass. The effect of the angular momentum of the source is manifested in the fact that inertial observers must be replaced by loca

C. J. de Matos, M. Tajmar

Using the linearized theory of general relativity, the gravitomagnetic analogue of the Barnett effect is derived. Further theoretical and experimental investigation is recommended, due to the expected macroscopic values of the gravitomagnetic field involved in this effect, and to the constraints which would appear on quantum theories of gravity, currently un

Neil J. Gunther, Giordano B. Beretta

The performance of CBIR algorithms is usually measured on an isolated workstation. In a real-world environment the algorithms would only constitute a minor component among the many interacting components. The Internet dramati-cally changes many of the usual assumptions about measuring CBIR performance. Any CBIR benchmark should be designed from a networked s

Daniele Quintella Mendes, Luis Alfredo Vidal de Carvalho

Thinking is one of the most interesting mental processes. Its complexity is sometimes simplified and its different manifestations are classified into normal and abnormal, like the delusional and disorganized thought or the creative one. The boundaries between these facets of thinking are fuzzy causing difficulties in medical, academic, and philosophical disc

B. P. Anderson, P. C. Haljan, C. A. Regal, D. L. Feder

We have created spatial dark solitons in two-component Bose-Einstein condensates in which the soliton exists in one of the condensate components and the soliton nodal plane is filled with the second component. The filled solitons are stable for hundreds of milliseconds. The filling can be selectively removed, making the soliton more susceptible to dynamical

S. S. Kancharla, C. J. Bolech

We study the optical response of a Mott Hubbard system in the framework of the half--filled Extended Hubbard Model using the Density Matrix Renormalization Group (DMRG) method. We discuss the appearance of excitonic features inside the spectral gap as the system goes from the Spin Density Wave (SDW) to the Charge Density Wave (CDW) phase.

J. Lefebvre, P. J. Poole, J. Fraser, G. C. Aers

The size distribution of self-assembled InAs quantum dots grown on (001) InP under the Stranski-Krastanow growth mode is controlled using selective area/chemical beam epitaxy, which allows the formation of quantum dots at specific locations. As the dimensions of the patterned areas are decreased from 1000 nm down to 50 nm or less, scanning electron microscop

Giuseppe Albertini

It is shown that the sl(2)q-invariant open antiferromagnetic XXZ spin chain with a boundary field has a gapless sector in the thermodynamic limit when its length is odd. Owing to a Temperley-Lieb equivalence of the spectra, the same conclusion is drawn for the purely biquadratic spin 1 chain with open boundaries and odd length.

A. Kadigrobov, R. I. Shekhter, M. Jonson

We show that quantum spin fluctuations in inhomogeneous ferromagnets drastically affect the Andreev reflection of electrons and holes at a ferromagnet-superconductor interface. As a result a strong long-range proximity effect appears, associated with electron-hole spin triplet correlations and persisting on a lenght scale typical for non-magnetic materials,

Etienne Boaknin, R. W. Hill, Cyril Proust, C. Lupien

Quasiparticle transport in the vortex state of an s-wave superconductor at T -> 0 was investigated by measuring the thermal conductivity of LuNi_2B_2C down to 70 mK in a magnetic field perpendicular to the heat current. In zero field, there is no electronic conduction, as expected for a superconducting gap without nodes. However, as soon as vortices enter th

R. J. Radwanski, Z. Ropka

By this Comment we would like to point out that the authors of Ref. 1 have ignored the orbital magnetism that makes the theory irrelevant to the real systems like NiO.It causes that the calculated result for the magnetic moment of NiO substantially disagrees with the experimental observation. PACS: 71.70.E, 75.10.D,

A. N. Vasil'ev, V. I. Marchenko, A. I. Smirnov, S. S. Sosin

The low-temperature electron spin resonance (ESR) spectra and the static magnetization data obtained for the stoichiometric single crystals of $β$-Na$_{0.33}$V$_2$O$_5$ indicate that this quasi-one-dimensional mixed valence (V4+/V5+) compound demonstrates at $T_N=22$ K the phase transition into the canted antiferromagnetically ordered state. The spontaneous

T. Franosch, D. R. Nelson

The response of a field-stabilized two-dimensional smectic to shear stress is discussed. Below a critical temperature the smectic film exhibits elastic response to an infinitesimal shear stress normal to the layering. At finite stresses free dislocations nucleate and relax the applied stress. The coupling of the dislocation current to the stress results in n

Rémy Mosseri

Some exact results are given, that connect, for a general magnitude of the interaction term $U$, the repulsive and attractive Hubbard model, in terms of the eigenspectra and quantum diffusion properties. In particular, it is shown that, for some initial conditions, the quantum evolution cannot differenciate between the attractive and repulsive models. These

V. A. Skrebnev

The existence of the linear on the order parameter term of the thermodynamic functions expansion near the critical point is justified. The criticism of the arguments, used for the rejection of the odd-power expansion terms of the ferromagnets thermodynamic functions is presented. It is shown, that taking into account the linear term in expansion one achieves

A. Isacsson

The dynamics of a nanoelectromechanical system in the form of a three-terminal tunneling device is studied by analytical and numerical methods. The main results are the existence of bistable stationary states resulting in directly detectable chaotic behavior.

M. M. Savosta, V. D. Doroshev, V. A. Borodin, Yu. G. Pashkevich

The NQR on Ba nuclei was studied in four samples of BaBiO3 prepared in different ways and, in addition, in BaPbO3. The spectrum of $^{137}$Ba at T=4.2 K consists of relatively broad line centered near 18 MHz for all BaBiO3 samples and near 13 MHz for BaPbO3. The integrated intensity of $^{137}$Ba resonance in ceramic sample BaBiO3 synthesized at 800 C is app

R. Cafiero, S. Luding, H. J. Herrmann

We study a two-dimensional gas of inelastic rough spheres, driven on the rotational degrees of freedom. Numerical simulations are compared to mean-field (MF) predictions with surprisingly good agreement for strong coupling of rotational and translational degrees of freedom -- even for very strong dissipation in the translational degrees. Although the system

Heinz-Olaf Müller, Miha Furlan, Thomas Heinzel, Klaus Ensslin

Background charge rearrangements in metallic single-electron transistors are modelled in two-level tunnelling systems as a Poisson process with a scale parameter as only variable. The model explains the recent observation of asymmetric Coulomb blockade peak spacing distributions in metallic single-electron transistors. From the scale parameter we estimate th

E. Schachinger, J. P. Carbotte

Charge carrier-spin excitation spectral densities constructed from optical data and varying with temperature are used to calculate various properties of the charge carrier dynamics. Temperature (T) variations of such properties are sensitive to the changes in the spectral density brought about by the growth in the 41 meV spin resonance as T is lowered. The m

M. P. Das, F. Green

We examine critically the idea that fractional charges may carry electrical current in a conductor, much as do the normal electrons in a metallic Fermi liquid. We explore a range of issues that have gained the status of indispensability for analyzing conductance and shot noise in fractionally charged systems. For these fundamental transport problems, however

B. Abdullaev, M. Musakhanov, A. Nakamura

We determine approximate formula for the ground state energy of anyons in 2D parabolic well which is valid for the arbitrary anyonic factor νand number of particles N in the system. We assume that centre of mass motion energy is not excluded from the energy of the system. Formula for ground state energy calculated by variational principle contains logarithmi

Joonhyun Yeo, M. A. Moore

We calculate various thermodynamic quantities of vortex liquids in a layered superconductor by using the nonperturbative parquet approximation method, which was previously used to study the effect of thermal fluctuations in two-dimensional vortex systems. We find there is a first-order transition between two vortex liquid phases which differ in the magnitude

M. J. Bhaseen

We obtain the disorder averaged (critical) four-point correlation functions for N species of (two-dimensional Euclidean) Dirac fermions subject to a (Gaussian) random su(N) gauge field. The replica approach and the strong disorder approach yield identical results, as one might expect in the light of recent developments in the N=2 case [1]. We establish a con

Min S. Yun, J. E. Hibbard

We have mapped the 2.6 mm CO (1-0) emission in three optically selected "Toomre Sequence" mergers (NGC 520, NGC 3921, NGC 4676). The molecular gas distribution is well resolved by the observations. For NGC 520 and NGC 4676A, the nuclear gas concentrations form a disk- or a ring-like structure, and the gas kinematics are regular and are consistent wit

S. G. Djorgovski, R. J. Brunner, A. A. Mahabal, S. C. Odewahn

We review some of the scientific opportunities and technical challenges posed by the exploration of the large digital sky surveys, in the context of a Virtual Observatory (VO). The VO paradigm will profoundly change the way observational astronomy is done. Clustering analysis techniques can be used to discover samples of rare, unusual, or even previously unk

Raymundo Baptista, M. S. Catalan

(Abridged) We report on the analysis of high-speed photometry of the dwarf nova EX Dra through its outburst cycle with eclipse mapping techniques. The eclipse maps show evidence of the formation of a one-armed spiral structure in the disc at the early stages of the outburst and reveal how the disc expands during the rise until it fills most of the primary Ro

J. C. Brandt, S. R. Heap, F. M. Walter, E. A. Beaver

We analyze HST/GHRS spectra of AB Doradus, the prototypical ultra-rapidly rotating K dwarf. We observed chromospheric (Mg II) and transition region (C II, Si IV, C IV, and N V) lines periodically throughout the stellar rotation period, and provide a low dispersion stellar atlas of 78 emission lines. The quiescent line profiles of the chromospheric and transi

Eric D. Feigelson

When observed with sufficiently high spatial resolution and sensitivity, star formation regions are unusually complex X-ray sources. Low-mass protostars and T Tauri stars, Herbig Ae/Be stars, OB and Wolf-Rayet stars are seen at levels $28 \leq \log L_x \leq 34$ erg/s. High-amplitude variability from magnetic reconnection flares are often present. From past s

Rolf A. Jansen, Marijn Franx, Daniel Fabricant

[O II] lambda 3727 Angstrom is often used as a tracer of star formation at intermediate redshifts (z > 0.4), where Halpha is not easily observed. We use the spectrophotometric data of the Nearby Field Galaxy Survey to investigate the range and systematic variation in observed [O II]/Halpha emission line ratio as a function of galaxy luminosity at low redshif

S. A. Colgate, H. Li, V. Pariev

(abridged) The interpretation of Faraday rotation measure maps of AGNs within galaxy clusters has revealed regions, $\sim 50-100$ kpc, that are populated with large, $\sim 30 μ$ G magnetic fields. The magnetic energy of these coherent regions is $\sim 10^{59-60}$ ergs, and the total magnetic energy over the whole cluster ($\sim 1$ Mpc across) is expected to

T. W. Jones

Cosmic-rays are ubiquitous, but their origins are surprisingly difficult to understand. A review is presented of some of the basic issues common to cosmic particle accelerators and arguments leading to the likely importance of diffusive shock acceleration as a general explanation. The basic theory of diffusive shock acceleration is outlined, followed by a di

Karl E. Haisch, Elizabeth A. Lada, Robert K. Pina, Charles M. Telesco

We present the results of the first broadband 10.8 um survey of the NGC 2024 cluster. The mid-infrared data were combined with our previously published JHKL photometry in order to construct spectral energy distributions for all detected sources. The main scientific goals were to investigate the nature of the young stellar objects (YSOs) in the cluster, and t

E. Emsellem, D. Greusard, F. Combes, D. Friedli

We present new stellar kinematical profiles of four galaxy hosts of active galactic nuclei, using the CO bandhead around 2.3 micron with the ISAAC/VLT spectrograph. We find that the nuclear bars or discs, embedded in large-scale primary bars, have all a decoupled kinematics, in the sense that the maximum of the rotational velocity occurs in the nuclear regio

H. Li, S. A. Colgate, B. Wendroff, R. Liska

(abridged) We study the nonlinear evolution of the Rossby wave instability in thin disks using global 2D hydrodynamic simulations. The key questions we are addressing in this paper are: (1) What happens when the instability becomes nonlinear? Specifically, does it lead to vortex formation? (2) What is the detailed behavior of a vortex? (3) Can the instabilit

S. L. Bridle

We compare and combine likelihood functions of the cosmological parameters Omega_m, h and sigma_8 from the CMB, type Ia supernovae and from probes of large scale structure. We include the recent results from the CMB experiments BOOMERANG and MAXIMA-1. Our analysis assumes a flat LambdaCDM cosmology with a scale-invariant adiabatic initial power spectrum. Fir

A. D. Biggs, I. W. A. Browne, P. N. Wilkinson

Radio monitoring of the gravitational lens system B0218+357 reveals it to be a highly variable source with variations on timescales of a few days correlated in both images. This shows that the variability is intrinsic to the background lensed source and suggests that similar variations in other intraday variable sources can also be intrinsic in origin.

Ofer Lahav

We generalise the procedure for joint estimation of cosmological parameters to allow freedom in the relative weights of various probes. This is done by including in the joint Likelihood function a set of 'Hyper-Parameters', which are dealt with using Bayesian considerations. The resulting algorithm is simple to implement. We illustrate the method by

G. D. Schmidt, L. Ferrario, D. T. Wickramasinghe, P. S. Smith

High-quality phase-resolved optical spectropolarimetry is presented for the magnetic cataclysmic variable V884 Her. The overall circular polarization during active accretion states is low and only slightly variable in the range 5000-8000A. However, the polarization is highly structured with wavelength, showing very broad polarization humps, narrow features t

A. E. Dolphin, L. Makarova, I. D. Karachentsev, V. E. Karachentseva

We present HST/WFPC2 observations of UGC 4483, an irregular galaxy in the M81/NGC 2403 complex. Stellar photometry was carried out with HSTphot, and is complete to V ~ 26.0 and I ~ 24.7. We measure the red giant branch tip at I = 23.56 +/- 0.10 and calculated a distance modulus of (m-M)o = 27.53 +/- 0.12 (corresponding to a distance of 3.2 +/- 0.2 Mpc), plac

A. C. Quillen

Because a chaotic zone can reduce the long timescale capture probabilities and cause catastrophic events such as close encounters with a planet or star during temporary capture, the dynamics of migrating planets is likely to be strongly dependent on the widths of the resonance chaotic zones. Previous theoretical work on the resonant capture of particles into

Tadashi Takayanagi, Seiji Terashima, Tadaoki Uesugi

In this paper we give the boundary string field theory description of brane-antibrane systems. From the world-sheet action of brane-antibrane systems we obtain the tachyon potential and discuss the tachyon condensation exactly. We also find the world-volume action including the gauge fields. Moreover we determine RR-couplings exactly for non-BPS branes and b

Yuji Okawa, Hirosi Ooguri

We study coupling of noncommutative gauge theories on branes to closed string in the bulk. We derive an expression for the gauge theory operator dual to the bulk graviton, both in bosonic string theory and superstring theory. In either case, we find that the coupling is different from what was expected in the literature when the graviton is polarized in the

Li-Xin Li

If a Kerr black hole is connected to a disk rotating around it by a magnetic field, the rotational energy of the Kerr black hole provides an energy source for the radiation of the disk in addition to disk accretion. The black hole exerts a torque on the disk, which transfers energy and angular momentum between the black hole and the disk. If the black hole r

Benjamin Grinstein, Detlef R. Nolte, Witold Skiba

We find a static solution to Einstein's field equations on a five-dimensional orbifold with a compact S_1/Z_2 fifth direction and Poincare invariant 3+1 sections. The solution describes a theory with bulk cosmological constant and 3-branes at the orbifold fixed points which carry matter density and pressure in addition to tension. The radius of the fifth

PHENIX Collaboration, K. Adcox

We present results for the charged-particle multiplicity distribution at mid-rapidity in Au - Au collisions at sqrt(s_NN)=130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find $dN_{ch}/dη_{|η=0} = 622 \pm 1 (stat) \pm 41 (syst)$. The results, analyzed as a function of centrality, show a steady rise of the particle dens

K. C. Hewitt, J. C. Irwin

Bi2Sr2CaCu2O{8 + δ} crystals with varying hole concentrations (0.12 < p < 0.23) were studied to investigate the effects of doping on the symmetry and magnitude of the superconducting gap. Electronic Raman scattering experiments that sample regions of the Fermi surface near the diagonal (B_{2g}) and principal axes (B_{1g}) of the Brillouin Zone have been util

Mihnea Popa, Mike Roth

In this paper we study the relationship between two different compactifications of the space of vector bundle quotients of an arbitrary vector bundle on a curve. One is Grothendieck&#39;s Quot scheme, while the other is a moduli space of stable maps to the relative Grassmannian. We establish an essentially optimal upper bound on the dimension of the two comp

Yurii A. Neretin

Consider the pseidounitary group $G=U(p,q)$ and its compact subgroup $K=U(p)$. We construct an explicit unitary intertwining operator from the tensor product of a holomorphic representation and a antiholomorphic representation of $G$ to the space $L^2(G/K)$. This implies the existense of a canonical action of the group $G\times G$ in $L^2(G/K)$. We also give

J. L. Domenech-Garret, M. A. Sanchis-Lozano

We extend our previous analysis on inclusive heavy quarkonia hadroproduction to the whole Upsilon(nS) (n=1,2,3) resonance family. We use a Monte Carlo framework with the colour-octet mechanism implemented in the PYTHIA event generator. We include in our study higher order QCD effects such as initial-state emission of gluons and Altarelli-Parisi evolution of

Xiaotong Song

Analytical and numerical results, for the orbital and spin content carried by different quark flavors in the baryons, are given in the chiral quark model with symmetry breaking. The reduction of the quark spin, due to the spin dilution in the chiral splitting processes, is transferred into the orbital motion of quarks and antiquarks. The orbital angular mome

M. I. Gorenstein, A. P. Kostyuk, L. McLerran, H. Stoecker

We consider the production of the open charm and J/psi mesons in heavy ion collisions at BNL RHIC. We discuss several recently developed pictures for J/psi production and argue that a measurement at RHIC energies is crucial for disentangling these different descriptions.

Julian Barbour, Brendan Foster, Niall Ó Murchadha

We give a derivation of general relativity and the gauge principle that is novel in presupposing neither spacetime nor the relativity principle. We consider a class of actions defined on superspace with two key properties. The first is 3-coordinate invariance. This is the only postulated symmetry, and it leads to the standard momentum constraint. The second

Johannes Berg, Anita Mehta

The dynamics of spins on a random graph with ferromagnetic three-spin interactions is used to model the compaction of granular matter under a series of taps. Taps are modelled as the random flipping of a small fraction of the spins followed by a quench at zero temperature. We find that the density approached during a logarithmically slow compaction - the ran

Philippe Grangier

An attempt is made to formulate quantum mechanics (QM) in physical rather than in mathematical terms. It is argued that the appropriate conceptual framework for QM is &#34;contextual objectivity&#34;, which includes an objective definition of the quantum state. This point of view sheds new light on topics such as the reduction postulate and the quantum measu

R. A. Battye, P. M. Sutcliffe

The Skyrme model is a classical field theory which has topological soliton solutions. These solitons are candidates for describing nuclei, with an identification between the numbers of solitons and nucleons. We have computed numerically, using two different minimization algorithms, minimum energy configurations for up to 22 solitons. We find, remarkably, tha

G. Curio, A. Klemm, D. Luest, S. Theisen

We discuss the vacuum structure of type IIA/B Calabi-Yau string compactifications to four dimensions in the presence of n-form H-fluxes. These will lift the vacuum degeneracy in the Calabi-Yau moduli space, and for generic points in the moduli space, N=2 supersymmetry will be broken. However, for certain `aligned&#39; choices of the H-flux vector, supersymme

A. Yu. Illarionov, A. G. Litvinenko, G. I. Lykasov

The fragmentation of deuterons into pions with nonzero angle emitted in the kinematical region forbidden for free nucleon-nucleon collisions is analyzed. The inclusive relativistic invariant spectrum of pions and the tensor analyzing power ${\rm A}_{YY}$ are investigated within the framework of an impulse approximation using different kinds of the deuteron w

G. C. Branco, Andre de Gouvea, M. N. Rebelo

We discuss CP violation in the quark sector within a novel approach to the Yukawa puzzle proposed by Arkani-Hamed and Schmaltz, where Yukawa hierarchies result from localising the Standard Model quark field wave-functions, at different positions (in the extra dimensions) in a ``fat-brane.&#39;&#39; We show that at least two extra dimensions are necessary in

Thoralf Chrobok, Volker Perlick

An observer surrounded by sufficiently small spherical light sources at a fixed distance will see a pattern of elliptical images distributed over the sky, owing to the distortion effect (shearing effect) of the spacetime geometry upon light bundles. In lowest non-trivial order with respect to the distance, this pattern is completely determined by the conform

D. Baranov, V. Yarunin

The shift of a maxon-roton He-4 excitation spectrum E via the He-3 admixture is considered theoretically. The Bogoliubov formula for E(ρ, g) as a function of Bose-condensate density ρand of He-4/He-4 interaction g is used as an element of partition function formalism of the whole system, presented in the form of a path (functional) integral. The dependence o

D. I. Kazakov

The present lectures contain an introduction to low energy supersymmetry, a new symmetry that relates bosons and fermions, in particle physics. The Standard Model of fundamental interactions is briefly reviewed, and the motivation to introduce supersymmetry is discussed. The main notions of supersymmetry are introduced. The supersymmetric extension of the St

V. V. Prudnikov, P. V. Prudnikov, A. A. Fedorenko

A field-theoretic description of the critical behaviour of the weakly disordered systems is given. Directly, for three- and two-dimensional systems a renormalization analysis of the effective Hamiltonian of model with replica symmetry breaking (RSB) potentials is carried out in the two-loop approximation. For case with 1-step RSB the fixed points (FP&#39;s)

Robert W. Johnson, Michael J. Teper

The spectrum of glueballs in 2+1 dimensions is calculated within an extended class of Isgur-Paton flux tube models and is compared to lattice calculations of the low-lying SU(N) glueball mass spectra. Our modifications of the model include a string curvature term and different ways of dealing with the flux tube width. We find that the generic model is remark

P. Bain

We obtain the supergravity solution which describes a bound state of D-string/anti-D-string pairs attached to different fixed planes of an orbifold, in type IIB string theory compactified on T^4/Z_2. For parameters at which the conformal field theory point of view predicts stability, the solution displays a repulson-like singularity. However, we observe that

P. Frick, R. Stepanov, A. Shukurov, D. Sokoloff

Coherent structures in the distribution of the Faraday rotation measure of extragalactic radio sources are isolated using wavelet transformation technique. Signatures of the magnetic fields in the local (Orion) spiral arm, the Sagittarius and Carina arms, the synchrotron Loop I and, possibly, the Perseus arm have been revealed using the RM catalogues of Sima

B. Fuchs

The shearing sheet model of a galactic disk is studied anew. The theoretical description of its dynamics is based on three building blocks: Stellar orbits, which are described here in epicyclic approximation, the collisionless Boltzmann equation determining the distribution function of stars in phase space, and the Poisson equation in order to take account o

H. Banerjee, D. Chatterjee, P. Mitra

The role of a chiral U(1) phase in the quark mass in QCD is analysed from first principles. In operator formulation, there is a parity symmetry and the phase can be removed by a change in the representation of the Dirac gamma matrices. Moreover, these properties are also realized in a Pauli-Villars regularized version of the theory. In the functional integra

Immanuel Bloch, Michael Köhl, Markus Greiner, Theodor W. Hänsch

We report on the atom optical manipulation of an atom laser beam. Reflection, focusing and its storage in a resonator are demonstrated. Precise and versatile mechanical control over an atom laser beam propagating in an inhomogeneous magnetic field is achieved by optically inducing spin-flips between atomic ground states with different magnetic moment. The ma

S. Ahlig, R. Alkofer, C. Fischer, M. Oettel

We introduce diquarks as separable correlations in the two-quark Green&#39;s function to facilitate the description of baryons as relativistic three-quark bound states. These states then emerge as solutions of Bethe-Salpeter equations for quarks and diquarks that interact via quark exchange. When solving these equations we consider various dressing functions

Michel Caffarel, Patrick Azaria, Bertrand Delamotte, Dominique Mouhanna

Using a {\it collective} Monte Carlo algorithm we study the low-temperature and long-distance properties of two systems of two-dimensional classical tops. Both systems have the same spin-wave dynamics (low-temperature behavior) as a large class of Heisenberg frustrated spin systems. They are constructed so that to differ only by their topological properties.

Cong-Feng Qiao

Recent developments in theory on the calculation of γ^* γ^* reaction at high energies, in the aim of detecting the BFKL Pomeron signals, are briefly introduced. The importance of the NLO QCD corrections to the Photon Impact Factor in the game is highlighted.

T. M. Gassym

The coupled system of Boltzman equations for the interacting system of electrons, positrons and photons in high external electric, E, and arbitrary magnetic, H, fields is solved. The consideration is made under the conditions of arbitrary heating and the mutual drag of carriers and photons. The non-stationary and non-uniform distribution function of photons

Frédéric Grosshans, Philippe Grangier

We discuss the criteria presently used for evaluating the efficiency of quantum teleportation schemes for continuous variables. Using an argument based upon the difference between 1-to-2 quantum cloning (quantum duplication) and 1-to-infinity cloning (classical measurement), we show that a fidelity value larger than 2/3 is required for successful quantum tel

P. G. Silvestrov, H. Schomerus, C. W. J. Beenakker

We study the correction of errors that have accumulated in an entangled state of spins as a result of unknown local variations in the Zeeman energy (B) and spin-spin interaction energy (J). A non-degenerate code with error rate kappa can recover the original state with high fidelity within a time kappa^1/2 / max(B,J) -- independent of the number of encoded q

Sibasish Ghosh, Guruprasad Kar, Anirban Roy, Debasis Sarkar

Very recently, it was shown by Ghosh, Kar, Roy and Sen (\emph{Entanglement vs. Noncommutativity in Teleportation}, quant-ph/0010012) that if it is \emph{a priori} known that the state to be teleported is from a commuting set of qubits, a separable channel is sufficient. We show that 1 ebit of entanglement is a necessary resource to teleport a qubit even when

F. Cannata, M. Ioffe

The approach of multi-dimensional SUSY Quantum Mechanics is used in an explicit construction of exactly solvable 3-body (and quasi-exactly-solvable $N$-body) matrix problems on a line. From intertwining relations with time-dependent operators, we build exactly solvable non-stationary scalar and $2\times 2$ matrix 3-body models which are time-dependent extens

Arvind

The existence of entangled quantum states gives extra power to quantum computers over their classical counterparts. Quantum entanglement shows up qualitatively at the level of two qubits. We show that if no entanglement is envolved then whatever one can do with qubits can also be done with classical optical systems. We demonstrate that the one- and the two-b

Alberto Barchielli

The theory of measurements continuous in time in quantum mechanics (quantum continual measurements) has been formulated by using the notions of instrument, positive operator valued measure, etc., by using quantum stochastic differential equations and by using classical stochastic differential equations (SDE&#39;s) for vectors in Hilbert spaces or for trace-c

Jiangfeng Du, Mingjun Shi, Jihui Wu, Xianyi Zhou

Bernstein and Varizani have given the first quantum algorithm to solve parity problem in which a strong violation of the classical imformation theoritic bound comes about. In this paper, we refine this algorithm with fewer resource and implement a two qubits algorithm in a single query on an ensemble quantum computer for the first time.

K. Bane, H. Hayano, K. Kubo, T. Naito

In April 2000 the single bunch energy spread, bunch length, horizontal emittance, and vertical emittance were measured as functions of current in KEK&#39;s ATF damping ring. In this report the measurement results are analyzed in light of intrabeam scattering theory. The measurements are found to be relatively consistent with theory, although the measured eff

M. -C. Firpo, Y. Elskens

Gibbs statistical mechanics is derived for the Hamiltonian system coupling self-consistently a wave to N particles. This identifies Landau damping with a regime where a second order phase transition occurs. For nonequilibrium initial data with warm particles, a critical initial wave intensity is found: above it, thermodynamics predicts a finite wave amplitud

A. Finne, L. Groenberg, R. Blaauwgeers, V. B. Eltsov

Sputtered Nb thin-film LC resonators for low frequencies at 0.5 MHz have been fabricated and tested in the temperature range 0.05--1 K in magnetic fields up to 30 mT. Their Q value increases towards decreasing temperature as sqrt(T) and reaches 10^3 at 0.05 K. As a function of magnetic field Q is unstable and displays variations up to 50%, which are reproduc

Karl L. F. Bane, Zenghai Li

The injector linacs of the JLC/NLC project include the prelinac, the e+ drive linac, the $e- booster, and the $e+ booster. The first three will be S-band machines, the last one, an L-band machine. We have demonstrated that by using detuning alone in the accelerator structure design of these linacs we will have acceptable tolerances for emittance growth due t

Volodymyr Shpytko, Jurij Darewych

We study two-particle systems in a model quantum field theory, in which scalar particles and spinor particles interact via a mediating scalar field. The Lagrangian of the model is reformulated by using covariant Green&#39;s functions to solve for the mediating field in terms of the particle fields. This results in a Hamiltonian in which the mediating-field p

N. Itaco, L. Coraggio, A. Covello, A. Gargano

The doubly odd Ta isotopes are studied within the framework of the particle-rotor model. The main aim of this study is to obtain information on the neutron-proton interaction in deformed nuclei, with particular attention focused on the role of the tensor force. To this end, both zero-range abd finite-range phenomenological interactions are considered. Compar

R. Averbeck, R. Holzmann, V. Metag, R. S. Simon

Chemical and thermal freeze-out of the hadronic fireball formed in symmetric collisions of light, intermediate-mass, and heavy nuclei at beam energies between 0.8A GeV and 2.0A GeV are discussed in terms of an equilibrated, isospin-symmetric ideal hadron gas with grand-canonical baryon-number conservation. For each collision system the baryochemical potentia

Andrei Maimistov

The models of the non-linear optics in which solitons were appeared are considered. These models are of paramount importance in studies of non-linear wave phenomena. The classical examples of phenomena of this kind are the self-focusing, self-induced transparency, and parametric interaction of three waves. At the present time there are a number of the theori

D. Levi, J. Negro, M. A. del Olmo

The discrete heat equation is worked out in order to illustrate the search of symmetries of difference equations. It is paid an special attention to the Lie structure of these symmetries, as well as to their dependence on the derivative discretization. The case of q-symmetries for discrete equations in a q-lattice is also considered.

Steven Duplij, Wladyslaw Marcinek

The categories with noninvertible morphisms are studied analogously to the semisupermanifolds with noninvertible transition functions. The concepts of regular n-cycles, obstruction and the regularization procedure are introduced and investigated. It is shown that the regularization of a category with nonivertible morphisms and obstruction form a 2-category.

J. Feng, M. Shcherbina, B. Tirozzi

We estimate the critical capacity of the zero-temperature Hopfield model by using a novel and rigorous method. The probability of having a stable fixed point is one when $α\le 0.113$ for a large number of neurons. This result is an advance on all rigorous results in the literature and the relationship between the capacity $α$ and retrieval errors obtained he

Vadim Yu. Kaloshin, Brian Hunt

Let M be a compact manifold of dimension at least 2, Diff^r(M) be the space of C^r diffeomorphisms of M. Define for any diffeomorphism f in Diff^r(M) number of isolated periodic points of period n by P_n(f)=# {isolated x in M: f^n(x)=x}. Artin--Mazur proved that for a dense set of diffeomorphisms the number of periodic points P_n(f) growth at most exponentia

Joel Merker

The reflection function of a smooth CR diffeomorphism between two minimal real analytic hypersurfaces is everywhere real analytic.

Joel Merker

A formal invertible equivalence between two minimal real analytic hypersurfaces converges if and only if the hypersurfaces are holomorphically nondegenerate