August 2000 arXiv papers — page 20

A. de Gouvea, S. Lola, K. Tobe

Supersymmetry with R-parity violation (RPV) provides an interesting framework for naturally accommodating small neutrino masses. Within this framework, we discuss the lepton-flavour violating (LFV) processes mu -> e gamma, mu -> eee, and mu -> e conversion in nuclei. We make a detailed study of the observables related to LFV in different RPV models, and comp

M. Klasen

We calculate total and differential cross sections for sfermion production in $e^+e^-$ annihilation and in photon-photon collisions with arbitrary photon polarization. The total cross section at a polarized photon collider is shown to be larger than the $e^+e^-$ annihilation cross section up to the kinematic limit of the photon collider.

S. Berge, M. Klasen, Y. Umeda

We calculate total and differential cross sections for the production of sfermion pairs in photon-photon collisions, including contributions from resolved photons and arbitrary photon polarization. Sfermion production in photon collisions depends only on the sfermion mass and charge. It is thus independent of the details of the SUSY breaking mechanism, but h

K. Zuber

A generalisation of the neutrinoless double beta decay process is presented. Neutrinoless double beta decay measures only one out of nine possible effective Majorana neutrino masses in case of three flavours. Limits obtained for all the matrix elements - some of them for the first time - are presented using data from $μ- e$ conversion, neutrino-nucleon scatt

Wei-Shu Hou, A. Soni

We point out new ways to search for charmless baryonic B decays: baryon pair production in association with $η^\prime$ is very likely as large as or even a bit larger than two body $Kπ/ππ$ modes. We extend our argument, in weaker form, to $B\to γ+ X_s$ and $\ellν+X$. Although calculations are not reliable, estimates give branching ratios of order $10^{-5}$--

W. Alles, L. Frassinetti

We apply the see-saw mechanism and an SO(10) model to neutrino masses and mixing in order to estimate the heavy Majorana masses. We discuss shortly the decay modes of heavy Majorana neutrinos and calculate their contribution to the lepton number violating processes μ\to eγ, τ\toμγand τ\to eγ.

D. Jido, T. Hatsuda, T. Kunihiro

We show that both the linear and the non-linear chiral models give an enhancement of the pi-pi cross section near the 2pi threshold in the scalar-iso-scalar (I=J=0) channel in nuclear matter. The reduction of the chiral condensate, i.e., the partial chiral restoration in nuclear matter, is responsible for the enhancement in both cases. We extract an effectiv

Kazuhiro Tobe

We discuss Lepton-Flavour-Violating phenomena such as $μ\to e γ$, $μ\to eee$, and $μ\to e$ conversion in nuclei in SUSY models with and without R-parity. We stress that experimental searches for all the LFV processes are important to distinguish between the different models.

Sin Kyu Kang, Jung Dae Kim

Effects of CP violation on the supersymmetric electroweak correction to the $ρ$ parameter are investigated. To avoid the EDM constraints, we require that arg$(μ)<10^{-2}$ and the non-universal trilinear couplings $A_f=(0,0,A_0)$ and also assume that gluinos are heavier than 400 GeV. The CP phase $ϕ_t=$ arg($A_0$) leads to large enhancement of the relative ma

G. L. Kane, James D. Wells

High-energy data has been accumulating over the last ten years, and it should not be ignored when making decisions about the future experimental program. In particular, we argue that the electroweak data collected at LEP, SLC and Tevatron indicate a light scalar particle with mass less than 500 GeV. This result is based on considering a wide variety of theor

John H. Schwarz

These four lectures, addressed to an audience of graduate students in experimental high energy physics, survey some of the basic concepts in string theory. The purpose is to convey a general sense of what string theory is and what it has achieved. Since the characteristic scale of string theory is expected to be close to the Planck scale, the structure of st

ALEPH Collaboration

The lifetimes of the Bbar0 and B- mesons are measured using a sample of about four million hadronic Z decays collected from 1991 to 1995 with the ALEPH detector at LEP. The data sample has been recently reprocessed, achieving a substantial improvement in the tracking performance. Semileptonic decays of Bbar0 and b- mesons are partially reconstructed by ident

Curt Cutler, David Ian Jones

We calculate the effect of gravitational wave (gw) back-reaction on realistic neutron stars (NS&#39;s) undergoing torque-free precession. By `realistic&#39; we mean that the NS is treated as a mostly-fluid body with an elastic crust, as opposed to a rigid body. We find that gw&#39;s damp NS wobble on a timescale tau_{theta} approx 2 x 10^5 yr [10^{-7}/(DId/I

H. S. Sharatchandra, H. Gopalkrishna Gadiyar

Non-Abelian Gauss law is interpreted in terms of area bits described in a local frame which fit together into closed surfaces and the Non-Abelian Stokes law in terms of length bits described in a local frame which fit together into closed loops. A new equation relating the area variables and the phase space variables (or equivalently, angular momentum variab

Scott Hazelhurst

Network firewalls and routers use a rule database to decide which packets will be allowed from one network onto another. By filtering packets the firewalls and routers can improve security and performance. However, as the size of the rule list increases, it becomes difficult to maintain and validate the rules, and lookup latency may increase significantly. O

G. Korniss, C. J. White, P. A. Rikvold, M. A. Novotny

We study the two-dimensional kinetic Ising model below its equilibrium critical temperature, subject to a square-wave oscillating external field. We focus on the multi-droplet regime where the metastable phase decays through nucleation and growth of many droplets of the stable phase. At a critical frequency, the system undergoes a genuine non-equilibrium pha

R. Chitra, R. Citro

It is known that in certain non-bipartite quasi-one dimensional spin systems in a magnetic field, in addition to the usual Pauli coupling of the spins to the field, new parity breaking three spin interactions, i.e. chiral spin interactions, are induced at higher order due to virtual processes involving the intrinsic electronic nature of the underlying spins.

Kurt Broderix, Kamal K. Bhattacharya, Andrea Cavagna, Annette Zippelius

By means of molecular dynamics simulations, we study the stationary points of the potential energy in a Lennard-Jones liquid, giving a purely geometric characterization of the energy landscape of the system. We find a linear relation between the degree of instability of the stationary points and their potential energy, and we locate the energy where the inst

Ron Lifshitz

It is argued that the definition of quasicrystals should not include the requirement that they possess an axis of symmetry that is forbidden in periodic crystals. The term &#34;quasicrystal&#34; should simply be regarded as an abbreviation for &#34;quasiperiodic crystal,&#34; possibly with two provisos, as discussed below. The argument is supported by theore

Guo-meng Zhao, H. Keller

We report precise measurements and quantitative data analysis on the low-temperature resistivity of several ferromagnetic manganite films. We clearly show that there exists a T^{4.5} term in low-temperature resistivity, and that this term is in quantitative agreement with the quantum theory of two-magnon scattering for half metallic ferromagnets. Our present

G. Fagas, G. Cuniberti, K. Richter

We study contact effects on electron transport across a molecular wire sandwiched between two semi-infinite (carbon) nanotube leads as a model for nanoelectrodes. Employing the Landauer scattering matrix approach we find that the conductance is very sensitive to parameters such as the coupling strength and geometry of the contact. The conductance exhibits ma

Brahim Elattari, Tsampikos Kottos

We study both analytically and numerically how the electronic structure and the transport properties of a two-dimensional disordered system are modified in the presence of resonances. The energy dependence of the density of states and the localization length at different resonance energies and strengths of coupling between resonances and random states are de

Sutapa Mukherji

We study the generalized $n$ component model of a driven diffusive system with annealed random drive in the large $n$ limit. This non-equilibrium model also describes conserved order parameter dynamics of an equilibrium model of ferromagnets with dipolar interaction. In this limit, at zero temperature a saddle point approximation becomes exact. The length sc

Marc Potters, Jean-Philippe Bouchaud, Dragan Sestovic

We propose a new `hedged&#39; Monte-Carlo (HMC) method to price financial derivatives, which allows to determine simultaneously the optimal hedge. The inclusion of the optimal hedging strategy allows one to reduce the financial risk associated with option trading, and for the very same reason reduces considerably the variance of our HMC scheme as compared to

Laurent Pizzagalli, Giulia Galli, John E. Klepeis, Francois Gygi

In order to control and tailor the properties of nanodots, it is essential to separate the effects of quantum confinement from those due to the surface, and to gain insight into the influence of preparation conditions on the dot physical properties. We address these issues for the case of small Ge clusters (1-3 nm), using a combination of empirical and first

Indranil Rudra, S. Ramasesha, Diptiman Sen

Beginning with a Heisenberg spin Hamiltonian for the manganese ions in the Mn_12 Ac molecule, we find a number of low-energy states of the system. We use these states to solve the time-dependent Schrodinger equation and find the magnetization of the molecule in the presence of a slowly varying magnetic field. We study the effects of the field sweep rate, fou

Daniel L. Miller

The difference of actions between nearly lying unstable ``8&#39;&#39; and ``0&#39;&#39; like trajectories in two dimensions is computed by methods of chaotic dynamics. We found it to be equal to $pYΘ/2$, where $Θ$ is angle between paths at cross, $Y$ is distance between paths, and $p$ is momentum. This kind of periodic trajectories contributes $τ^2$ (interfe

Choon-Lin Ho, Chung-I Chou

We present a simple and complete variational approach to the one-dimensional quantum Frenkel-Kontorova model. Dirac&#39;s time-dependent variational principle is adopted together with a Hatree-type many-body trial wavefunction for the atoms. The single-particle state is assumed to have the Jackiw-Kerman form. We obtain an effective classical Hamiltonian for

Yong Baek Kim

It was recently shown that dipolar composite fermions emerged from the lowest-Landau-level formulation of the quantum Hall effect give rise to similar results as those of the Chern-Simons gauge theory in the long wavelength and low energy limit. We ask whether this correspondence is still valid at finite wavevectors where the excitations do not necessarily l

Y. Zhang, N. P. Ong, P. W. Anderson, D. A. Bonn

In high-purity crystals of YBa_2Cu_3O_7, the quasiparticle (qp) lifetime τand the (weak-field) thermal Hall conductivity κ_{xy} undergo dramatic increases below 90K. We present a detailed picture of the behavior of κ_{xy} at low temperature, in particular its scaling properties, which are directly relevant to the issue of whether Landau quantization of the q

Hidetoshi Nishimori, David Sherrington

We prove that the distribution functions of magnetization and spin glass order parameter coincide on the Nishimori line in the phase diagram of the $\pm J$ Ising model in any dimension. This implies absence of replica symmetry breaking because the distribution function of magnetization consists only of two delta functions, suggesting the same simple structur

Masatoshi Imada, Shigeki Onoda

Superconducting mechanism of cuprates is discussed in the light of the proximity of the Mott insulator. The proximity accompanied by suppression of coherence takes place in an inhomogeneous way in the momentum space in finite-dimensional systems. Studies on instabilities of metals consisted of such differentiated electrons in the momentum space are reviewed

Haijun Zhou

As a prototype of systems bearing a localization-delocalization transition, the strand-separation (melting) process in a double-stranded biopolymer is studied by a mapping to a quantum-mechanical problem with short-ranged potentials. Both the bounded and the extensive eigenmodes of the corresponding Schrodinger equation are considered and exact expressions f

Pan Hui, Rong Lu, Jia-Lin Zhu, Yi Zhou

Macroscopic quantum coherence and spin-phase interference are studied between excited levels in single-domain ferromagnetic particles in a magnetic field along the hard anisotropy axis. The system has the general structure of magnetocrystalline anisotropy, such as biaxial, trigonal, tetragonal, and hexagonal symmetry. This study not only just yields the prev

Andisheh Mahdavi

With the success of the Chandra and XMM missions and the maturation of gravitational lensing techniques, powerful constraints on the orbital structure of cluster dark matter halos are possible. I show that the X-ray emissivity and mass of a galaxy cluster uniquely specify the anisotropy and velocity dispersion profiles of its dark matter halo. I consider hyd

N. W. Evans, C. M. Carollo, P. T. de Zeeuw

This paper presents the properties of a family of scale-free triaxial haloes. We adduce arguments to suggest that the velocity ellipsoids of such models are aligned in conical coordinates. We provide an algorithm to find the set of conically aligned velocity second moments that support a given density against the gravity field of the halo. The case of the lo

N. W. Evans, M. I. Wilkinson, P. Guhathakurta, E. K. Grebel

The last few months have seen the measurements of the radial velocities of all of the dwarf spheroidal companions to the Andromeda galaxy (M31) using the spectrographs (HIRES and LRIS) on the Keck Telescope. This paper summarises the data on the radial velocities and distances for all the companion galaxies and presents new dynamical modelling to estimate th

M. Blazejowski, M. Sikora, R. Moderski, G. Madejski

We demonstrate the importance of near-infrared radiation from hot dust for Compton cooling of electrons/positrons in quasar jets. In our model, we assume that the non-thermal radiation spectra observed in OVV quasars are produced by relativistic electrons/positrons accelerated in thin shells which propagate down the jet with relativistic speeds. We show that

Chris Mihos

We use numerical simulations to study the development of gas/star offsets in the tidal tails of merging galaxies. These offsets are shown to be a natural consequence of the radially extended HI spatial distribution in disk galaxies, coupled with internal dissipation in the gaseous component driven by the interaction. This mechanism explains the observed gas/

J. J. Birriel, B. R. Espey, R. E. Schulte-Ladbeck

Symbiotic stars are binary systems consisting of a hot star, typically a white dwarf, and a cool giant companion. The wind from the cool star is ionized by the radiation from the hot star, resulting in the characteristic combination of sharp nebular emission lines and stellar molecular absorption lines in the optical spectrum. Most of the emission lines are

B. T. Draine

Our current understanding of interstellar dust is summarized at an introductory level. Submicron-sized interstellar dust grains absorb and scatter light, and reradiate the absorbed energy in the infrared. The grain population spans a range of sizes, from molecules containing only tens of atoms, to particles containing 10^{10} atoms. Most of the grain mass ap

B. T. Draine, Frank Bertoldi

Observations of H2 line emission have revealed higher-than-expected gas temperatures in a number of photodissociation fronts. We discuss the heating and cooling processes in photodissociation regions. Observations of NGC 2023 are compared to a theoretical model in which there is substantial gas at temperatures T = 500-1000K heated by photoelectric emission a

S. Galtier, S. V. Nazarenko, A. C. Newell, A. Pouquet

We derive a weak turbulence formalism for incompressible MHD. Three-wave interactions lead to a system of kinetic equations for the spectral densities of energy and helicity. We find energy spectra solution of the kinetic equations. The constants of the spectra are computed exactly and found to depend on the amount of correlation between the velocity and the

S. N. Arteha

A self-consistent statistical approach to the problem of planetary and stellar magnetism is suggested. The mechanism of magnetic field generation in the astronomical objects, where the existence of fields is associated with the axial rotation of objects, is discussed. In the general case different forces produce partial R-separation of the charges. As a resu

R. I. Hynes, P. A. Charles, C. A. Haswell, J. Casares

We describe Doppler tomography obtained in the 1998 outburst of the neutron star low mass X-ray binary (LMXB) XTE J2123-058. This analysis, and other aspects of phase-resolved spectroscopy, indicate similarities to SW Sex systems, except that anomalous emission kinematics are seen in HeII, whilst phase 0.5 absorption is confined to H alpha. This separation o

R. I. Hynes, C. A. Haswell

The Hubble Space Telescope has now observed four black hole X-ray transients in outburst under an ongoing Target-of-Opportunity program: GRO J0422+32 (1994), GRO J1655-40 (1996), XTE J1859+226 (1999-2000) and XTE J1118+480 (2000). We summarise the highlights of this program to date, including a diversity of spectral energy distributions, correlated X-ray/UV/

L. Pentericci, J. D. Kurk, H. J. A Rottgering, G. K. Miley

VLT spectroscopic observations of Ly alpha--excess objects in the field of the clumpy radio galaxy 1138-262 at z=2.16 have led to the discovery of 14 galaxies and one QSO at approximately the same distance as the radio galaxy. All galaxies have redshifts in the range 2.16 \pm 0.02, centered around the redshift of the radio galaxy, and are within a projected

T. Yaqoob

While it is understood that the origin of the Cosmic X-ray Background (CXRB) can be explained in terms of a combination of obscured and unobscured AGN, the identity of these obscured AGN showing up in large numbers at faint fluxes remains unclear. Deep surveys are showing up increasingly large numbers of AGN at the faintest fluxes which have broad optical li

S. Piraino, A. Santangelo, P. Kaaret

We report results from simultaneous RossiXTE and BeppoSAX observations of the neutron-star x-ray binary and type I X-ray burster 4U1728-34. The source was found in a high luminosity state, L_X near 0.1 L_Edd, and quasiperiodic oscillations were detected at 1284 +/- 6 Hz, the highest frequency ever observed from this source. The x-ray spectrum shows a broad,

Eric M. Schlegel, Robert Petre, E. J. M. Colbert, Scott Miller

We describe a series of observations of NGC 1313 using the ROSAT HRI with a combined exposure time of 183.5 ksec. The observations span an interval between 1992 and 1998; the purpose of observations since 1994 was to monitor the X-ray flux of SN1978K, one of several luminous sources in the galaxy. No diffuse emission is detected in the galaxy to a level of ~

S. Kontinen, J. Harju, A. Heikkila, L. K. Haikala

Two dense dark cloud cores representing different stages of dynamical evolution were observed in a number of molecular spectral lines. One of the cores, Cha- MMS1 in the Chamaeleon cloud I contains a Class 0 protostar, whereas the other, CrA C in the R Coronae Australis cloud, is pre-stellar. We find that the cores have very different chemical compositions.

E. Pantin, C. Waelkens, P. O. Lagage

We report here the first resolved images of the circumstellar dust disk around the Pre-Main-Sequence star HD 100546. These near-infrared images were obtained in J and short K bands with the adaptive optics system ADONIS at the ESO observatory. A bright disk extending 2 arcsec (200 AU) far from the star and viewed with an inclination with respect to the line

Francis Bernardeau, Jean-Philippe Uzan

We present investigations of lens phenomenological properties of cosmic strings for deep galaxy surveys. General results that have obtained for lineic energy distribution are presented first. We stress that generically the local convergence always vanishes in presence of strings although there might be some significant distortions. We then propose a simplifi

Patrick McDonald, Robert J. Scherrer, Terry P. Walker

Energy injected into the Cosmic Microwave Background at redshifts z<10^6 will distort its spectrum permanently. In this paper we discuss the distortion caused by annihilations of relic particles. We use the observational bounds on deviations from a Planck spectrum to constrain a combination of annihilation cross section, mass, and abundance. For particles wi

Martin Lopez-Corredoira

Withdrawm. Public data of COBE-DMR are not perfectly subtracted from dipole. Therefore, the Galactic latitude dependence is affected by the remnants of the dipole and the results previously announced in this paper about this are not valid. Anyway, the suspect of a high Galactic contamination announced in another paper (Lopez-Corredoira 1999; A&A 346, 369) is

Volker Springel, Martin White, Lars Hernquist

We have performed a sequence of high resolution hydrodynamic simulations of structure formation in a LCDM model to study the thermal and kinetic Sunyaev-Zel&#39;dovich (SZ) effects. Including only adiabatic gas physics, we demonstrate that our simulations for the thermal effect are converged down to sub-arcminute scales. In this model, the angular power spec

C. A. Bertulani, D. S. Dolci

The production of electron-positron pairs with the capture of the electron in an atomic orbital is investigated for the conditions of the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider LHC). Dirac wave functions for the leptons are used, taking corrections to orders of Z.alpha into account. The dependence on the transverse momentum tran

S. Ahmed, CLEO Collaboration

This article describes improved measurements by CLEO of the $B^0 \to D_s^+ D^{*-}$ and $B^0 \to D_s^{*+} D^{*-}$ branching fractions, and first evidence for the decay $B^+ \to D_s^{(*)+} \bar{D}^{**0}$, where $\bar{D}^{**0}$ represents the sum of the $\bar{D}_1(2420)^0$, $\bar{D}_2^*(2460)^0$, and $\bar{D}_1(j=1/2)^0$ L=1 charm meson states. Also reported is

István Szapudi, Marc Postman, Tod R. Lauer, William Oegerle

Constraints on the validity of the hierarchical gravitational instability theory and the evolution of biasing are presented based upon measurements of higher order clustering statistics in the Deeprange Survey, a catalog of $\sim710,000$ galaxies with $I_{AB} \le 24$ derived from a KPNO 4m CCD imaging survey of a contiguous $4^{\circ} \times 4^{\circ}$ regio

M. O. Dzero, L. P. Gor&#39;kov, A. K. Zvezdin

The puzzling properties of the first order phase transition in YbInCu$_4$ and its alloys in the wide range of magnetic fields and temperatures are perfectly described in terms of a simple entropy transition for free Yb ions. In particular, it turns out that the transition line in the $(B,T)$-plane is very close to the elliptic shape, as it has been observed

Nick E. Mavromatos, John Rizos

We consider the O(a&#39;) string effective action, with Gauss-Bonnet curvature-squared and fourth-order dilaton-derivative terms, which is derived by a matching procedure with string amplitudes in five space-time dimensions. We show that a non-factorizable metric of the Randall-Sundrum (RS) type, with four-dimensional conformal factor Exp(-2 k|z|), can be a

Daniel Gottesman, Alexei Kitaev, John Preskill

Quantum error-correcting codes are constructed that embed a finite-dimensional code space in the infinite-dimensional Hilbert space of a system described by continuous quantum variables. These codes exploit the noncommutative geometry of phase space to protect against errors that shift the values of the canonical variables q and p. In the setting of quantum

Vatche Sahakian

We study the phases of the 1+1 dimensional Non-Commutative Open String theory on a circle. We find that the length scale of non-commutativity increases at strong coupling, the coupling in turn being dressed by a power of D-string charge. The system is stringy at around this length scale, with dynamics involving an interplay between the open and wrapped close

Peter Mattsson, Patrick Dorey

We find the spectrum of boundary bound states for the sine-Gordon model with Dirichlet boundary conditions, closing the bootstrap and providing a complete description of all the poles in the boundary reflection factors. The boundary Coleman-Thun mechanism plays an important role in the analysis. Two basic lemmas are introduced which should hold for any 1+1-d

Robert Oeckl

Both, spin and statistics of a quantum system can be seen to arise from underlying (quantum) group symmetries. We show that the spin-statistics theorem is equivalent to a unification of these symmetries. Besides covering the Bose-Fermi case we classify the corresponding possibilities for anyonic spin and statistics. We incorporate the underlying extended con

J. Ananias Neto, C. Neves, W. Oliveira

In this paper the SU(2) Skyrme model will be reformulated as a gauge theory and the hidden symmetry will be investigated and explored in the energy spectrum computation. To this end we purpose a new constraint conversion scheme, based on the symplectic framework with the introduction of Wess-Zumino (WZ) terms in an unambiguous way. It is a positive feature n

X. Fan, M. A. Strauss, D. P. Schneider, J. E. Gunn

This is the fourth paper in a series aimed at finding high-redshift quasars from five-color imaging data taken along the Celestial Equator by the SDSS. during its commissioning phase. In this paper, we use the color-selected sample of 39 luminous high-redshift quasars presented in Paper III to derive the evolution of the quasar luminosity function over the r

Xin-Nian Wang, Mikols Gyulassy

The energy and centrality dependence of the charged multiplicity per participant nucleon is shown to be able to differentiate between final-state saturation and fixed scale pQCD models of initial entropy production in high-energy heavy-ion collisions. The energy dependence is shown to test the nuclear enhancement of the mini-jet component of the initial cond

X. Fan, M. A. Strauss, G. T. Richards, J. A. Newman

This is the third paper in a series aimed at finding high-redshift quasars from five-color (u&#39;g&#39;r&#39;i&#39;z&#39;) imaging data taken along the Celestial Equator by the SDSS during its commissioning phase. In this paper, we first present the observations of 14 bright high-redshift quasars (3.66<z<4.77, i^*<20) discovered in the SDSS Fall Equatorial

Roland Kirschner, George K. Savvidy

We consider scattering of electromagnetic plane waves on a D3-brane spike which emanates normal to D3-barne in the extra space direction. We are interested in studying physical effects on D3-brane which are produced by a spike attached to D3-brane. We have observed that the spike sucks almost all electromagnetic radiation and therefore acts like a black hole

Tatsuo Kobayashi, Koichi Yoshioka

We discuss a framework for communicating supersymmetry breaking to the visible sector where the radius modulus, which determines the size of extra dimensions, has an auxiliary vacuum expectation value. The modulus couplings generate mass splitting in Kaluza-Klein supermultiplets and they act as messengers of supersymmetry breaking. The soft masses are expres

M. Alimohammadi, M. Khorrami

The phase structure of the generalized Yang--Mills theories is studied, and it is shown that {\it almost} always, it is of the third order. As a specific example, it is shown that all of the models with the interaction $\sum_j (n_j-j+N)^{2k}$ exhibit third order phase transition. ($n_j$ is the length of the $j$-th row of the Yang tableau corresponding to U($

P. G. Silvestrov

Non-Hermitean operators may appear during the calculation of a partition function in various models of statistical mechanics. The tail eigen-states, having anomalously small real part of energy $Re(\eps)$, became naturally important in this case. We consider the distribution of such states and the form of eigenfunctions for the particle propagating in an ima

Gregoire Ribordy, Juergen Brendel, Jean-Daniel Gautier, Nicolas Gisin

A detailled analysis of quantum key distribution employing entangled states is presented. We tested a system based on photon pairs entangled in energy-time optimized for long distance transmission. It is based on a Franson type set-up for monitoring quantum correlations, and uses a protocol analogous to BB84. Passive state preparation is implemented by polar

Dietmar G. Fischer, Holger Mack, Matthias Freyberger

We discuss the problem of transfering a qubit from Alice to Bob using a noisy quantum channel and only finite resources. As the basic protocol for the transfer we apply quantum teleportation. It turns out that for a certain quality of the channel direct teleportation combined with qubit purification is superior to entanglement purification of the channel. If

Z. Bajnok, L. Palla, G. Takacs, F. Wagner

The two-frequency sine-Gordon model is examined. The focus is mainly on the case when the ratio of the frequencies is 1/2, given the recent interest in the literature. We discuss the model both in a perturbative (form factor perturbation theory) and a nonperturbative (truncated conformal space approach) framework, and give particular attention to a phase tra

WA98 Collaboration, M. M. Aggarwal

Transverse energy, charged particle pseudorapidity distributions and photon transverse momentum spectra have been studied as a function of the number of participants (N_{part}) and the number of binary nucleon-nucleon collisions (N_{coll}) in 158 A GeV Pb+Pb collisions over a wide impact parameter range. A scaling of the transverse energy pseudorapidity dens

Changhyun Ahn, Jinsub Paeng

By analyzing SU(3)xU(1) invariant stationary point, studied earlier by Nicolai and Warner, of gauged N=8 supergravity, we find that the deformation of S^7 gives rise to nontrivial renormalization group flow in a three-dimensional boundary super conformal field theory from N=8, SO(8) invariant UV fixed point to N=2, SU(3)xU(1) invariant IR fixed point. By exp

T. Hirano, T. Konishi, R. Namiki

We report an experimental quantum key distribution that utilizes balanced homodyne detection, instead of photon counting, to detect weak pulses of coherent light. Although our scheme inherently has a finite error rate, it allows high-efficiency detection and quantum state measurement of the transmitted light using only conventional devices at room temperatur

Naomichi Hatano, James E. Gubernatis

A bivariate version of the multicanonical Monte Carlo method and its application to the simulation of the three-dimensional $\pm J$ Ising spin glass are described. We found the autocorrelation time associated with this particular multicanonical method was approximately proportional to the system volume, which is a great improvement over previous methods appl

J. M. Miller, D. W. Fox, T. DiMatteo, R. Wijnands

We report evidence for an Fe K-alpha fluorescence line feature and disk reflection in the Very High, High, and Low State X-ray spectra of the galactic microquasar XTE J1748-288 during its June~1998 outburst. Spectral analyses are made on data gathered throughout the outburst by the Rossi X-ray Timing Explorer Proportional Counter Array. Gaussian line, relati

Mario Castagnino

The relation between renormalization and short distance singular divergencies in quantum field theory is studied. As a consequence a finite theory is presented. It is shown that these divergencies are originated by the multiplication of distributions (and worse defined mathematical objects). Some of them are eliminated defining a multiplication based in dime

Roberto Aquilano, Mario Castagnino

The universe time-asymmetry is essentially produced by its low-entropy unstable initial state. Using quanlitative arguments, Paul Davies has demonstrated that the universe expansion may diminish the entropy gap, therefore explaining its low-entropy state, with respect to the maximal possible entropy at any time. This idea is implemented in a qualitative way\

Mario A. Castagnino, Edgerd Gunzig

064<p type=&#34;texpara&#34; tag=&#34;Body Text&#34; et=&#34;abstract&#34; bin=&#34;clone&#34; >There are two schools, or lines of thought, that try to unify the apparently divergent laws of dynamics and thermodynamics and to explain the observed time-asymmetry of the universe, and most of its sub-systems, in spite of the fact that these systems are driven b

O. K. Belyaev, O. V. Ershov, I. G. Maltsev, V. B. Stepanov

The new 1.8 MeV proton RFQ was completed and started operation in the IHEP in 1997. It was built according to the plan of modernization of the injection system to the booster of the IHEP proton synchrotron.

A. K. Popov, Alexander S. Bayev, Thomas F. George, Vladimir M. Shalaev

New feasibity of coherent quantum control of four-wave mixing processes in a resonant Doppler-broadened medium are studied. We propose a technique which enables one to enhance the quantum efficiency of nonlinear optical conversion. At the same time, it allows one to decrease the required intensities of the fundamental beams compared to those necessary in the

J. E. Clendenin

Recent advances in electron and positron sources have resulted in new capabilities driven in most cases by the increasing demands of advanced accelerating systems. Electron sources for brighter beams and for high average-current beams are described. The status and remaining challenges for polarized electron beams are also discussed. For positron sources, rec

A. Kuriyama, J. da Providencia, Y. Tsue, M. Yamamura

Various works performed by the present authors in the 1990s are reviewed. The topics discussed in this paper are mainly related to the time-evolution of the coherent and the squeezed states of the systems obeying the su(2)- and the su(1,1)-algebra. The formulations are based on the basic idea of the boson mapping and the TDHF theory in canonical form. Under

Clemens Adler, Alexei Denisov, Edmundo Garcia, Michael Murray

High Energy collisions of nuclei usually lead to the emission of evaporation neutrons from both ``beam&#39;&#39; and ``target&#39;&#39; nuclei. At the RHIC heavy ion collider with 100GeV/u beam energy, evaporation neutrons diverge by less than $~2$ milliradians from the beam axis Neutral beam fragments can be detected downstream of RHIC ion collisions (and a

N. G. Marchuk

We suggest model equations, which, from some point of view, describe local interaction of three physical fields: a field of matter, an electromagnetic field and a gravitational field. A base of the model is a field of matter described by the wave function of fermion satisfying the equation similar to Dirac equation for electron. Electromagnetic and gravitati

Andrius Tamulis

The concordance orders of many algebraic order two knots of ten or fewer crossings have been heretofore unknown. We use Casson-Gordon invariants and twisted Alexander polynomials to find that, in all but one case, these knots do not have concordance order two. We also find that a certain family of algebraic order two twisted doubles of the unknot have infini

Michael Baake, Robert V. Moody

We study self-similar measures of Hutchinson type, defined by compact families of contractions, both in a single and multi-component setting. The results are applied in the context of general model sets to infer, via a generalized version of Weyl&#39;s Theorem on uniform distribution, the existence of invariant measures for families of self-similarities of r

Bong H. Lian, Andrey Todorov, Shing-Tung Yau

The computations that are suggested by String Theory in the B model requires the existence of degenerations of CY manifolds with maximum unipotent monodromy. In String Theory such a point in the moduli space is called a large radius limit (or large complex structure limit). In this paper we are going to construct one parameter families of $n$ dimensional Cal

Ashok Kumar Mittal, Ashok Kumar Gupta

In an earlier paper we introduced the notion of &#39;bifurcating continued fractions&#39; in a heuristic manner. In this paper a formal theory is developed for the &#39;bifurcating continued fractions&#39;.

Roger Carter, Bethany Marsh

Let U be the quantum group associated to a Lie algebra g of rank n. The negative part U^- of U has a canonical basis B with favourable properties, introduced by Kashiwara and Lusztig. The approaches of Kashiwara and Lusztig lead to a set of alternative parametrizations of the canonical basis, one for each reduced expression for the longest word in the Weyl g

M. Scheunert

Recently, the R-matrix of the symplecto-orthogonal quantum superalgebra U_q(spo(2n|2m)) in the vector representation has been calculated. In the present work, this R-matrix is used to introduce the corresponding quantum supergroup SPO_q(2n|2m) and to construct an SPO_q(2n|2m)-covariant quantum Weyl superalgebra.

M. Scheunert

The R-matrix of the symplecto-orthogonal quantum superalgebra U_q(spo(2n|2m)) in the vector representation is calculated, and its basic properties are derived.

H. F. Jones, P. Parkin, D. Winder

We apply the linear delta expansion to the quantum mechanical version of the slow rollover transition which is an important feature of inflationary models of the early universe. The method, which goes beyond the Gaussian approximation, gives results which stay close to the exact solution for longer than previous methods. It provides a promising basis for ext

Matthias Neubert

We review recent advances in the theory of strong-interaction effects and final-state interactions in hadronic weak decays of heavy mesons. In the heavy-quark limit, the amplitudes for most nonleptonic, two-body B decays can be calculated from first principles and expressed in terms of semileptonic form factors and light-cone distribution amplitudes. We summ

C. Greub, P. Liniger

We calculate the alpha_s virtual corrections to the decay width for b --> s gluon in the standard model. Also the corresponding order alpha_s bremsstrahlung corrections are systematically calculated in this paper. The combined result is free of infrared and collinear singularities, in accordance with the KLN theorem. Taking into account the existing next-to-