May 1999 arXiv papers — page 13

M. Itakura

We present a simple, sophisticated method to capture renormalization group flow in Monte Carlo simulation, which provides important information of critical phenomena. We applied the method to $D=3,4$ lattice $ϕ^4$ model and obtained renormalization flow diagram which well reproduces theoretically predicted behavior of continuum $ϕ^4$ model. We also show that

S. Bund, Adriaan M. J. Schakel

A nonrelativistic Bose gas is represented as a grand-canonical ensemble of fluctuating closed spacetime strings of arbitrary shape and length. The loops are characterized by their string tension and the number of times they wind around the imaginary time axis. At the temperature where Bose-Einstein condensation sets in, the string tension, being determined b

S. Goette, U. Semmelmann

In this note, we look at estimates for the scalar curvature k of a Riemannian manifold M which are related to spin^c Dirac operators: We show that one may not enlarge a Kaehler metric with positive Ricci curvature without making k smaller somewhere on M. We also give explicit upper bounds for min(k) for arbitrary Riemannian metrics on certain submanifolds of

Haye Hinrichsen, Geza Odor

We investigate a class of parity-conserving solid-on-solid models which describe the growth of an interface by the deposition and evaporation of dimers. As a key feature of the models, evaporation of dimers takes place only at the edges of terraces, leading to a roughening transition between a smooth and a rough phase. We consider several variants of growth

Th. Feldmann, P. Kroll

We investigate the b-u skewed parton distributions (SPDs) for B->pi transitions and determine the contributions from several sources (overlaps of soft light-cone wave functions, quark-antiquark annihilations and meson resonances). The B->pi transition form factors, which are relevant in exclusive semi-leptonic and non-leptonic B-decays, are obtained by integ

Detlev Buchholz, Roberto Longo

It is shown that the modulus of any graded or, more generally, twisted KMS functional of a C*-dynamical system is proportional to an ordinary KMS state and the twist is weakly inner in the corresponding GNS-representation. If the functional is invariant under the adjoint action of some asymptotically abelian family of automorphisms, then the twist is trivial

M. Watzlawek, C. N. Likos, H. Loewen

The phase diagram of star polymer solutions in a good solvent is obtained over a wide range of densities and arm numbers by Monte Carlo simulations. The effective interaction between the stars is modeled by an ultrasoft pair potential which is logarithmic in the core-core distance. Among the stable phases are a fluid as well as body-centered cubic, face-cent

Chun-Khiang Chua, Xiao-Gang He, W-Y. P. Hwang

We show how nonzero Majorana neutrino masses can be radiatively generated by extending the MSSM with leptoquark chiral multiplets without violating R-parity. It is found that, with these particles, the R-parity conservation does not imply lepton number conservation. Neutrino masses generated at a one-loop level are closely related to the down quark mass matr

Chin-Kun Hu, Jau-Ann Chen, N. Sh. Izmailian, P. Kleban

We establish an intriguing connection between geometry and thermodynamics in the critical q-state Potts model on two-dimensional lattices, using the q-state bond-correlated percolation model (QBCPM) representation. We find that the number of clusters of the QBCPM has an energy-like singularity for q different from 1, which is reached and supported by exact r

B. C. Choudhary

Data from the complete MACRO detector have been used to search for magnetic monopoles (MMs) of all expected velocities. Scintillator, streamer tube (instrumented with specialized electronics) and nuclear track detectors have been used to search for signatures coming from MMs; the scintillator and nuclear track subdetectors were used also for searches for oth

Hisaki Hatanaka

We study dynamical gauge symmetry breaking via compactified space in the framework of SU(N) gauge theory in M^{d-1}\times S^1 (d=4,5,6) space-time. In particular, we study in detail the gauge symmetry breaking in SU(2) and SU(3) gauge theories when the models contain both fundamental and adjoint matter. As a result, we find that any pattern of gauge symmetry

Jens O. Andersen, Eric Braaten, Michael Strickland

We calculate the thermodynamic functions of a hot gluon plasma to leading order in hard-thermal-loop (HTL) perturbation theory. Effects associated with screening, gluon quasiparticles, and Landau damping are resummed to all orders. The ultraviolet divergences generated by the HTL propagator corrections can be cancelled by a counterterm that depends on the th

Steven H. Simon, P. M. Platzman

In ``interaction free'' measurements, one typically wants to detect the presence of an object without touching it with even a single photon. One often imagines a bomb whose trigger is an extremely sensitive measuring device whose presence we would like to detect without triggering it. We point out that all such measuring devices have a maximum sensit

B. Hladky, G. Drobny, V. Buzek

Nature provides us with a restricted set of microscopic interactions. The question is whether we can synthesize out of these fundamental interactions an arbitrary unitary operator. In this paper we present a constructive algorithm for realization of any unitary operator which acts on a (truncated) Hilbert space of a single bosonic mode. In particular, we con

F. A. Bovino, F. De Martini, V. Mussi

The new process of quantum-injection into an optical parametric amplifier operating in entangled configuration is adopted to amplify into a large dimensionality spin 1/2 Hilbert space the quantum entanglement and superposition properties of the photon-couples generated by parametric down-conversion. The structure of the Wigner function and of the field's

Yu. Lozovik, A. Filinov

The transmission of wave packets through tunneling barriers is studied in detail by the method of quantum molecular dynamics. The distribution function of the times describing the arrival of a tunneling packet in front of and behind a barrier and the momentum distribution function of the packet are calculated. The behavior of the average coordinate of a pack

Stephen L. Adler, Lawrence P. Horwitz

We give a general proof that Hughston's stochastic extension of the Schrödinger equation leads to state vector collapse to energy eigenstates, with collapse probabilities given by the quantum mechanical probabilities computed from the initial state. We also show that for a system composed of independent subsystems, Hughston's equation separates into

K. Bennaceur, J. Dobaczewski, M. Ploszajczak

Continuum effects in the weakly bound nuclei close to the drip-line are investigated using the analytically soluble Poschl-Teller-Ginocchio potential. Pairing correlations are studied within the Hartree-Fock-Bogoliubov method. We show that both resonant and non-resonant continuum phase space is active in creating the pairing field. The influence of positive-

Hartmuth Arenhoevel, Winfried Leidemann, Edward L. Tomusiak

For deuteron photo- and electrodisintegration the selection of complete sets of polarization observables is discussed in detail by applying a recently developed new criterion for the check of completeness of a chosen set of observables. The question of ambiguities and their resolution by considering additional observables is discussed for a numerical example

Yu. B. Ivanov, J. Knoll, D. N. Voskresensky

Within the real-time formulation of nonequilibrium field theory, generalized transport equations are derived avoiding the standard quasiparticle approximation. They permit to include unstable particles into the transport scheme. In order to achieve a self-consistent, conserving and thermodynamically consistent description, we generalize the Baym's $Φ$-fu

A. L. Pirozerski, M. A. Semenov-Tian-Shansky

The q-deformed version of the Drinfeld-Sokolov reduction is extended to the case of the algebra of 'complex size matrices'; this construction generalizes earlier results of B.Khesin and F.Malikov on universal DS reduction and follows the pattern of recent studies of q-deformed DS reduction which were started by E.Frenkel, N.Reshetikhin and one of the

Dusa McDuff

This paper studies the (small) quantum homology and cohomology of fibrations $p: P\to S^2$ whose structural group is the group of Hamiltonian symplectomorphisms of the fiber $(M,\om)$. It gives a proof that the rational cohomology splits additively as the vector space tensor product $H^*(M)\otimes H^*(S^2)$, and investigates conditions under which the ring s

Gh. Adam, S. Adam

Approximate $p$-point Leibniz derivation formulas as well as interpolatory Simpson quadrature sums adapted to oscillatory functions are discussed. Both theoretical considerations and numerical evidence concerning the dependence of the discretization errors on the frequency parameter of the oscillatory functions show that the accuracy gain of the present form

Mike Eastwood, Peter W. Michor

The Pluecker relations are equations which describe decomposable multivectors in $\bigwedge V$. We review all known versions, give some new ones, and decompose them into irreducible parts for the $GL(V)$-representations.

Jintai Ding

In this paper, we present the hidden symmetry behind the Faddeev-Reshetikhin-Takhtajan-Semenov-Tian-Shansky realization of quantum affine superalgebras $U_q(\hat {osp}(1,2))$ and add the q-Serre relation to the Drinfeld realization of $U_q(\hat {osp}(1,2))$ (math.QA/9712011) derived from the FRTS realization.

Ismail Zahed, Daniel Zwanziger

We show that all spatial gluon connected correlation functions in SU(N) or SO(N) QCD vanish at finite temperature and zero momentum in lattice Landau or Coulomb gauges, due to the proximity of the Gribov horizon. These observations also apply to QCD with two colors and an even number of flavors at large chemical potential. These nonperturbative results may h

G. Akemann

The microscopic spectrum of the QCD Dirac operator is shown to obey random matrix model statistics in the bulk region of the spectrum close to the origin using finite-volume partition functions.

Julien F. J. Salgado

Generalising a result of classical mechanics an infinite set of conserved quantities can be found for the bare equations of motion describing the evolution of a scalar field in out of equilibrium quantum field theory, in the large N approximation, with initial conditions corresponding to a thermal system of the free Hamiltonian. Using these new conserved qua

M. Mintchev, E. Ragoucy, P. Sorba, Ph Zaugg

We study the Yangian symmetry of the multicomponent Quantum Nonlinear Schrodinger hierarchy in the framework of the Quantum Inverse Scattering Method. We give an explicit realization of the Yangian generators in terms of the deformed oscillators algebra which naturally occurs in this framework.

Jens Ole Madsen, J. Luis Miramontes

An infinite series of Grassmann-odd and Grassmann-even flow equations is defined for a class of supersymmetric integrable hierarchies associated with loop superalgebras. All these flows commute with the mutually commuting bosonic ones originally considered to define these hierarchies and, hence, provide extra fermionic and bosonic symmetries that include the

Kenichi Horie

It is known that the quantization of a system defined on a topologically non-trivial configuration space is ambiguous in that many inequivalent quantum systems are possible. This is the case for multiply connected spaces as well as for coset spaces. Recently, a new framework for these inequivalent quantizations approach has been proposed by McMullan and Tsut

B. W. Harris, M. Klasen, J. Vossebeld

The precision of new HERA data on jet photoproduction opens up the possibility to discriminate between different models of the photon structure. This requires equally precise theoretical predictions from perturbative QCD calculations. In the past years, next-to-leading order calculations for the photoproduction of jets at HERA have become available. Using th

Antonio Masiero, Massimo Pietroni, Francesca Rosati

Recent data point in the direction of a cosmological constant dominated universe. We investigate the role of supersymmetric QCD with N_f < N_c as a possible candidate for dynamical cosmological constant (``quintessence&#39;&#39;). When N_f > 1, the multiscalar dynamics is fully taken into account, showing that a certain degree of flavor symmetry in the initi

Pedro Bicudo

Les We present a new perspective on the scalar meson puzzle from spontaneous breaking of chiral symmetry beyond BCS. We find that going beyond BCS does not produce a systematic shift of the hadron spectrum. We also show that coupled channels reduce the breaking of chiral symmetry, with the same Feynman diagrams that appear in the coupling of a scalar meson t

Carlo Oleari

In this talk, we consider the computation of D and B fragmentation functions in e+e- annihilation. We present an improved differential cross section that merges together the O(alpha_s^2) fixed-order calculation and the next-to-leading-logarithmic resummed one. We compare the results of fitting present data using the next-to-leading-log cross section, the O(a

N. Kivel, L. Mankiewicz

We have obtained a general solution of evolution equations for QCD twist-2 string operators in form of expansion over complete set of orthogonal eigenfunctions of evolution kernels in coordinate-space representation. In the leading logarithmic approximation the eigenfunctions can be determined using constraints imposed by conformal symmetry. Explicit formula

W. James Stirling, Anja Werthenbach

The vanishing of the cross section for particular points in phase space - radiation zeros - is examined for the process $ q \bar q \to W^+W^- γ$ at high energy. Unlike the process $q \bar q&#39; \to W^\pm γ$, actual zeros only occur in the soft-photon limit. However, for photon energies that are not too large, the cross section does exhibit deep dips in regi

Yu. L. Dokshitzer, G. Marchesini, B. R. Webber

The fully resummed next-to-leading-order perturbative calculation of the energy-energy correlation in $e^+e^-$ annihilation is extended to include the leading non-perturbative power-behaved contributions computed using the ``dispersive method&#39;&#39; applied earlier to event shape variables. The correlation between a leading (anti)quark and a gluon produce

B. Tseng, Cheng-Wei Chiang

Two-body charmless nonleptonic decays of $B_u \to V V$ are studied within the generalized factorization approach using a recent calculation of the effective Wilson coefficients $c^{eff}_i$, which are not only renormalization-scale and -scheme independent but also gauge invariant and infrared finite. After making a universal ansatz for the nonfactorizable con

CMD2 Collaboration

The decay $K_S^0 \to πe ν$ has been observed by the CMD-2 detector at the e^+e^- collider VEPP-2M at Novosibirsk. Of 6 million produced $K_L^0K_S^0$ pairs, $75 \pm 13$ events of the $K_S^0 \to πe ν$ decay were selected. The corresponding branching ratio is $B(K_S^0 \to πe ν)=(7.2 \pm 1.4)\times10^{-4}$. This result is consistent with the evaluation of $B(K_S

Yongsheng Gao, Frank Würthwein

The CLEO collaboration has studied two-body charmless hadronic decays of $B$ mesons into final states containing two pseudo-scalar mesons, or a pseudo-scalar and a vector meson. We summarize and discuss results presented during the winter/spring 1999 conference season, and provide a brief outlook towards future attractions to come. In particular, CLEO presen

John. Ellis, N. E. Mavromatos, D. V. Nanopoulos

A satisfactory theory of quantum gravity may necessitate a drastic modification of our perception of space-time, by giving it a foamy structure at distances comparable to the Planck length. It is argued in this essay that the experimental detection of such structures may be a realistic possibility in the foreseeable future. After a brief review of different

S. N. Manida

The theory of relativity was built up on linear Lorentz transformation. However, in his fundamental work &#34;Theory of Space, Time and Gravitation&#34; V.A.Fock shows that the general form of the transformation between the coordinates in the two inertial frames could be taken to be linear fractional. The implicit form of this transformation contains two con

Diego F. Torres

Theories with varying gravitational constant $G$ have been studied since long time ago. Among them, the most promising candidates as alternatives of the standard General Relativity are known as scalar-tensor theories. They provide consistent descriptions of the observed universe and arise as the low energy limit of several pictures of unified interactions. T

Arkady L. Kholodenko

This paper is extended and broadly generalized version of earlier published rapid communication, Phys.Rev.E, Vol.58, R 5213 (1998). It also elaborates on some problems which were left unsolved or just mentioned in Physics Reports Vol.298, 251 (1998). Applications of the obtained results include (but not limited to) polymer physics, classical and quantum chao

Thomas R. Lemberger, Aaron A. Pesetski, Stefan J. Turneaure

We calculate the factor by which thermal phase fluctuations, as distinct from phase-slip fluctuations, increase the inductance, LJ, of a resistively-shunted Josephson junction (JJ) above its mean-field value, L0. We find that quantum mechanics suppresses fluctuations when T drops below a temperature, TQ = h/kBGL0, where G is the shunt conductance. Examinatio

T. Timusk, B. W. Statt

We present an experimental review of the nature of the pseudogap in the cuprate superconductors. Evidence from various experimental techniques points to a common phenomenology. The pseudogap is seen in all high temperature superconductors and there is general agreement on the temperature and doping range where it exists. It is also becoming clear that the su

Eduardo Fradkin

In this talk I present a summary of recent work on tunnel junctions of a fractional quantum Hall fluid and an electron reservoir, a Fermi liquid. I consider first the case of a single point contact. This is a an exactly solvable problem from which much can be learned. I also discuss in some detail how these solvable junction problems can be used to understan

A. Perez-Garrido, M. A. Moore

Determination of the classical ground state arrangement of $N$ charges on the surface of a sphere (Thomson&#39;s problem) is a challenging numerical task. For special values of $N$ we have obtained using the ring removal method of Toomre, low energy states in Thomson&#39;s problem which have icosahedral symmetry where lines of dislocations run between the 12

L. Neubert, L. Santen, A. Schadschneider, M. Schreckenberg

In the present paper single-vehicle data of highway traffic are analyzed in great detail. By using the single-vehicle data directly empirical time-headway distributions and speed-distance relations can be established. Both quantities yield relevant information about the microscopic states. Several fundamental diagrams are also presented, which are based on t

Joel De Coninck, Salvador Miracle-Sole, Jean Ruiz

We consider the problem of the Winterbottom&#39;s construction and Young&#39;s equation in the presence of a rough substate and establish their microscopic validity within a 1+1-dimensional SOS type model. We then present the low temperature expansion of the wall tension leading to the Wenzel&#39;s law for the wall tension and its corrections. Finally, for a

Yasufumi Yamashita, Naokazu Shibata, Kazuo Ueda

We study the one-dimensional SU(4) exchange model under magnetic fields, which is the simplest effective Hamiltonian in order to investigate the quantum fluctuations concerned with the orbital degrees of freedom in coupled spin-orbit systems. The Bethe ansatz approaches and numerical calculations using the density matrix renormalization group method are empl

A. V. Zaitsev, A. F. Volkov, S. W. D. Bailey, C. J. Lambert

Phase-coherent diffusive transport through mesoscopic hybrid superconductor/normal metal tunneling structures is investigated. For a N-s-S two-barrier tunneling system with bulk S and N electrodes coupled by a mesoscopic superconducting constriction s, zero-bias conductance and non-linear I-V curves are calculated under the assumption that the dwell times of

Luis Brey

We study magnetic domain walls in double exchange materials. The domain wall width is proportional to the square root of the stiffness. In the double exchange model the stiffness has two terms: the kinetic energy and the Hartree term. The kinetic energy term comes from the decrease of the tunneling amplitude in the domain wall region. The Hartree term appear

R. Burioni, D. Cassi, A. Vezzani

In this letter we present the inversion of the Mermin-Wagner theorem on graphs, by proving the existence of spontaneous magnetization at finite temperature for classical spin models on transient on the average (TOA) graphs, i.e. graphs where a random walker returns to its starting point with an average probability $\bar F < 1$. This result, which is here pro

P. S. Swain, David Andelman

We consider a membrane both weakly and strongly adhering to a geometrically structured substrate. The interaction potential is assumed to be local, via the Deryagin approximation, and harmonic. Consequently, we can analytically describe a variety of different geometries: as well as randomly rough self-affine surfaces, smooth substrates interrupted by an isol

Eduard Obrado, Eduard Vives, Antoni Planes

We study isothermal magnetization processes in the Cu-Al-Mn intermetallic alloy. Hysteresis is observed at temperatures below the spin-freezing of the system. The characteristics of the hysteresis cycles as a function of temperature and Mn content (magnetic element) are obtained. At low temperature (5 K) a change from smooth to sharp cycles is observed with

Jae-Kwon Kim

It is shown by Monte Carlo method that the finite size scaling (FSS) holds in the two dimensional random-coupled Ising ferromagnet. It is also demonstrated that the form of universal FSS function constructed via novel FSS scheme depends on the strength of the random coupling for strongly disordered cases. Monte Carlo measurements of thermodynamic (infinite v

W. N. Kang, Wan-Seon Kim, S. J. Oh, Sung-Ik Lee

The mixed-state Hall resistivity and the longitudinal resistivity in HgBa_{2}CaCu_{2}O_{6}, HgBa_{2}Ca_{2}Cu_{3}O_{8}, and Tl_{2}Ba_{2}CaCu_{2}O_{8} thin films have been investigated as functions of the magnetic field up to 18 T. We observe the universal scaling behavior between ρ_{xy} and ρ_{xx} in the regions of the clean and the moderately clean limit. Th

R. J. Baxter

The free energy of the chiral Potts model has been obtained in two ways. The first used only the star-triangle relation, symmetries and invariances, and led to a system of equations that implicitly define the free energy, and from which the critical behaviour can be obtained. The second used the functional relations derived by Bazhanov and Stroganov, solving

Gregory L. Eyink

We show that time-correlation functions of arbitrary order for any random variable in a statistical dynamical system can be calculated as higher-order response functions of the mean history of the variable. The response is to a ``control term&#39;&#39; added as a modification to the master equation for statistical distributions. The proof of the relations is

Richard Jordan, Christophe Josserand

We present a statistical equilibrium model of self-organization in a class of focusing, nonintegrable nonlinear Schrodinger (NLS) equations. The theory predicts that the asymptotic-time behavior of the NLS system is characterized by the formation and persistence ofa large-scale coherent solitary wave, which minimizes the Hamiltonian given the conserved parti

A. Alvarez, E. Hernandez-Garcia, J. Tintore

Randomly-forced fluid flow in the presence of scale-unselective dissipation develops mean currents following topographic contours. Known mechanisms based on the scale-selective action of damping processes are not at work in this situation. Coarse-graining reveals that the phenomenon is a kind of noise-rectification mechanism, in which lack of detailed balanc

Kevin R. Vixie, David E. Sigeti, Murray Wolinsky

We explain why aliasing can be detected in a generic temporally-sampled stationary signal process. We then define a concept of stationarity that makes sense for single waveforms. (This is done without assuming that the waveform is a sample path of some underlying stochastic process.) We show how to use this concept to detect aliasing in sampled waveforms. Th

J. T. Lauroesch, David M. Meyer

We present high resolution (R~170,000) Kitt Peak National Observatory Co&#39;ude Feed telescope observations of the interstellar KI 7698 angstrom line towards 5 multiple star systems with saturated NaI components. We compare the KI absorption line profiles in each of the two (or three) lines of sight in these systems, and find significant differences between

J. P. D. Mittaz, F. J. Carrera, E. Romero-Colmenero, K. O. Mason

We present results of an extensive study of the X-ray spectral properties of sources detected in the RIXOS survey, that is nearly complete down to a flux limit of 3e-14 cgs (0.5-2 keV). We show that for X-ray surveys containing sources with low count rate spectral slopes estimated using simple hardness ratios in the ROSAT band can be biased. Instead we analy

J. Christopher Howk, Blair D. Savage, Dirk Fabian

We present ultraviolet interstellar absorption line measurements for the sightline towards the O9.5 V star mu Columbae obtained with the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope. These archival data represent the most complete GHRS interstellar absorption line measurements for any line of sight towards an early-type sta

S. J. Sciutto

A report on the characteristics of ultra-high energy air showers simulated with the AIRES program is presented. The AIRES system includes a fast simulating program which is an improved version of the well-known MOCCA program. The AIRES algorithms are briefly described and a series of results coming from the simulations are analyzed.

M. Cocchi, A. Bazzano, L. Natalucci, P. Ubertini

For the first time X-ray bursts have been detected from a sky position consistent with the one of GRS 1741.9-2853, a GRANAT transient source located only ~10&#39; from the Galactic Centre. A total of 3 bursts have been observed by the Wide Field Cameras telescopes on board BeppoSAX during a monitoring observation of the Sgr A region in August-September 1996.

M. D. Seaborne, W. Sutherland, H. Tadros, G. Efstathiou

We present a direct comparison of the clustering properties of two redshift surveys covering a common volume of space: the recently completed IRAS Point Source Catalogue redshift survey (PSCz) containing 14500 galaxies with a limiting flux of 0.6 Jy at 60 microns, and the optical Stromlo-APM survey containing 1787 galaxies in a region of 4300 deg^2 in the so

Gabriele Ghisellini

Nature succeeds in accelerating extended and massive objects to relativistic velocities. Jets in Active Galactic Nuclei and in galactic superluminal sources and gamma-ray bursts fireballs have bulk Lorentz factors from a few to several hundreds. A variety of effects then arises, such as the beaming of the produced radiation, light aberration, time contractio

P. Blasi, S. Colafrancesco

We calculate the fluxes of radio, hard X-rays and gamma-ray emission from clusters of galaxies, in the context of a secondary electron model (SEM). In the SEM the radiating electrons are produced by the decay of charged pions in cosmic ray (CR) interactions with the intracluster medium, while gamma ray emission is mainly contributed by the decay of neutral p

Luke O&#39;C Drury, Peter Duffy, David Eichler, Apostolos Mastichiadis

The recent detection of high energy gamma-rays coming from supernova remnants and active galactic nuclei has revived interest in the diffusive shock acceleration of electrons. In the present paper we examine the basis of the so-called ``box&#39;&#39; model for particle acceleration and present a more physical version of it. Using this we determine simple cri

C. J. Pethick, A. Akmal, V. R. Pandharipande, D. G. Ravenhall

A review of properties of matter in the interior of neutron stars is given. Particular attention is paid to recent many-body theory calculations of the properties of dense matter. Among topics discussed are the strong increase of tensor correlations at relatively low densities, the &#34;relativistic boost term&#34; in the interaction, and the sensitivity of

A. Marcowith, J. G. Kirk

The present work considers diffusive shock acceleration at non-relativistic shocks using a system of stochastic differential equations (SDE) equivalent to the Fokker-Planck equation. We compute approximate solutions of the transport of cosmic particles at shock fronts with a SDE numerical scheme. The momentum gain is given by implicit calculations of the flu

Eric W. Deutsch, Bruce Margon, Scott F. Anderson, Stefanie Wachter

We present new astrometric solutions and infrared Hubble Space Telescope observations of GX 17+2 (X1813-140), one of the brightest X-ray sources on the celestial sphere. Despite 30 years of intensive study, and the existence of a strong radio counterpart with a sub-arcsecond position, the object remains optically unidentified. The observed X-ray characterist

Ray Jayawardhana, Lee Hartmann, Giovanni Fazio, R. Scott Fisher

We present high-resolution mid-infrared observations of the nearby late-type young binary system Hen 3-600. The binary, at a distance of $\sim$ 50 pc, could be a member of the TW Hydrae Association, the nearest known group of young stars, with an age of a few million years. Our images make it possible for the first time to determine which star in the pair, s

M. Hirayama, L. R. Cominsky, V. M. Kaspi, F. Nagase

We report the results from X-ray and hard X-ray observations of the PSR B1259-63/SS 2883 system with the ASCA and CGRO satellites, performed between 1995 February and 1996 January when the pulsar was near apastron. The system was clearly detected in each of the two ASCA observations with luminosity in the 1-10 keV band of Lx = (9 +- 3) x10^32 (d/2 kpc)^2 erg

L. Tresse, M. Dennefeld, P. Petitjean, S. Cristiani

We present spectroscopic observations of galaxies lying within 1&#39; from the QSO J2233-606 in the HDF-S. Several are found to be coincident in redshift with absorption line systems seen in the HST spectrum of the QSO. We detect a new quasar with z=1.3360 at only 45&#34; angular separation from this QSO. This quasar pair is thus an ideal target for QSO envi

Martin Z. Bazant

The statistical behavior of the size (or mass) of the largest cluster in subcritical percolation on a finite lattice of size $N$ is investigated (below the upper critical dimension, presumably $d_c=6$). It is argued that as $N \to \infty$ the cumulative distribution function converges to the Fisher-Tippett (or Gumbel) distribution $e^{-e^{-z}}$ in a certain

N. I. Kochelev

It is shown that an instanton induced interaction between quarks produces a very deeply bound H-dibaryon with mass below 2M_N, M_H=1718 MeV. Therefore the H-dibaryon is predicted to be a stable particle. The reaction of photodisintegration of H-dibaryon to $2Λ$ in during of its penetration into cosmic microwave background will result in a new possible cut-of

P. Vranas, I. Tziligakis, J. Kogut

Domain wall fermions are defined on a lattice with an extra direction the size of which controls the chiral properties of the theory. When gauge fields are coupled to domain wall fermions the extra direction is treated as an internal flavor space. Here it is found that this is not the case for scalar fields. Instead, the interaction takes place only along th

Alexandre Blais, Alexandre M. Zagoskin

We demonstrate that complete set of gates can be realized in a DXD superconducting solid state quantum computer (quamputer), thereby proving its universality.

Markus Holzmann, Werner Krauth

We present a Monte Carlo calculation for up to $N \sim 20 000$ bosons in 3 D to determine the shift of the transition temperature due to small interactions $a$. We generate independent configurations of the ideal gas. At finite $N$, the superfluid density changes by a certain correlation function in the limit $a \to 0$; the $N \to \infty$ limit is taken afte

Andres Gomberoff, David Kastor, Donald Marolf, Jennie Traschen

We study fully localized BPS brane solutions in classical supergravity using a perturbative approach to the coupled Born-Infeld/bulk supergravity system. We derive first order bulk supergravity fields for world-volume solitons corresponding to intersecting M2-branes and to a fundamental string ending on a D3-brane. One interesting feature is the appearance o

A. M. Khvedelidze, H. -P. Pavel

A systematic method to calculate the low energy spectrum of SU(2) Yang-Mills quantum mechanics with high precision is given and applied to obtain the energies of the groundstate and the first few excited states.

T. Montaruli, M. Ambriola et al

We present updated results on the search for a neutrino signal from the core of the Earth and of the Sun induced by Weakly Interacting Massive Particles (WIMPs). In this paper we concentrate on neutralinos as WIMP candidates. The 971 and 642 events used respectively for the search from the Sun and from the Earth are compatible with the background of atmosphe

T. Montaruli, M. Ambriola et al

We use a sample of 990 upward-going muons, induced primarily by atmospheric neutrinos, to search for neutrinos of astrophysical origin. No evidence has been found using the event direction information. Flux limits of the order of 10^-15 cm^-2 s^-1 are imposed on current models for candidate point-sources. A space-time correlation search has been undertaken b

T. Montaruli, M. Ambriola et al

We report on the results of a Monte Carlo simulation study of a km^3 scale deep underwater Cherenkov detector aimed at detecting neutrinos of astrophysical origin. This analysis has been undertaken as part of the NEMO R&D project to develop such an experiment close to the Southern Italian coasts. We have studied the reconstruction capabilities of various arr

M. N. Mazziotta

The MACRO detector is located in the Gran Sasso Laboratory. MACRO's overburden varies from 3150 to 7000 hg/cm^2. A transition radiation detector (TRD) has been added to the MACRO detector in order to measure the residual energy of muons entering MACRO, i.e. the energy they have after passing through the Gran Sasso's rock overburden. The TRD consists of three

E. Balkovsky, A. Fouxon

We consider transport of dynamically passive quantities in the Batchelor regime of smooth in space velocity field. For the case of arbitrary temporal correlations of the velocity we formulate the statistics of relevant characteristics of Lagrangian motion. This allows to generalize many results obtained previously for the delta-correlated in time strain, thu

I. V. Anikin, A. E. Dorokhov, A. E. Maximov, L. Tomio

We develop a relativistic quark model for pion structure, which incorporates the non-trivial structure of the vacuum of Quantum Chromodynamics as modelled by instantons. Pions are boundstates of quarks and the strong quark-pion vertex is determined from an instanton induced effective lagrangian. The interaction of the constituents of the pion with the extern

David B. Kaplan, James V. Steele

Nonperturbative effective field theory calculations for NN scattering seem to break down at rather low momenta. By examining several toy models, we clarify how effective field theory expansions can in general be used to properly separate long- and short-range effects. We find that one-pion exchange has a large effect on the scattering phase shift near poles

G. Bonelli, L. Bonora, F. Nesti, A. Tomasiello

We extend the results found for Matrix String Theory to Heterotic Matrix String Theory, i.e. to a 2d O(N) SYM theory with chiral (anomaly free) matter and N=(8,0) supersymmetry. We write down the instanton equations for this theory and solve them explicitly. The solutions are characterized by branched coverings of the basis cylinder, i.e. by compact Riemann

D. C. Cabra, E. Fradkin, G. L. Rossini, F. A. Schaposnik

We propose an effective Lagrangian for the low energy theory of the Pfaffian states of the fractional quantum Hall effect in the bulk in terms of non-Abelian Chern-Simons (CS) actions. Our approach exploits the connection between the topological Chern-Simons theory and chiral conformal field theories. This construction can be used to describe a large class o

V. Antonelli, E. A. Kuraev, B. G. Shaikhatdenov

The process of large-angle high energy electron-positron scattering with emission of one hard photon almost collinear to one of the charged particles momenta is considered. The differential cross section with radiative corrections due to emission of virtual and soft real photons calculated to a power accuracy is presented. Emission of two hard photons and to

Giorgio Parisi, Federico Ricci-Tersenghi

In this paper we show that in systems where the probability distribution of the the overlap is non trivial in the infinity volume limit, the property of ultrametricity can be proved in general starting from two very simple and natural assumptions: each replica is equivalent to the others (replica equivalence or stochastic stability) and all the mutual inform

B. Revenu, A. Kim, R. Ansari, F. Couchot

A major problem in Cosmic Microwave Background (CMB) anisotropy mapping, especially in a total-power mode, is the presence of low-frequency noise in the data streams. If unproperly processed, such low-frequency noise leads to striping in the maps. To deal with this problem, solutions have already been found for mapping the CMB temperature fluctuations but no

S. -I. Ei, K. Fujii, T. Kunihiro

The renormalization group (RG) method as a powerful tool for reduction of evolution equations is formulated in terms of the notion of invariant manifolds. We start with derivation of an exact RG equation which is analogous to the Wilsonian RG equations in statistical physics and quantum field theory. It is clarified that the perturbative RG method constructs

B. Goldman, X. Delfosse, T. Forveille, C. Afonso et al

We report the discovery of two L dwarfs (the new spectral class defined for dwarfs cooler than the M type) in a two-epoch CCD proper motion survey of 413 square degrees, complemented by infrared photometry from DENIS. One of them has a strong lithium line and is therefore a brown dwarf. The other is a common proper motion companion to the mid-M dwarf LHS 102