October 1998 arXiv papers — page 7

H. Arisue, K. Tabata

We have calculated the large-$q$ expansion for the energy and magnetization cumulants at the first order phase transition point in the two-dimensional $q$-state Potts model to the 21st or 23rd order in $1/\sqrt{q}$ using the finite lattice method. The obtained series allow us to give highly convergent estimates of the cumulants for $q>4$. The results confirm

P. J. Bussey

A survey is presented of the various processes measurable at HERA in which two photons are involved. Their current experimental status and future prospects are discussed.

H. T. Jadallah, J. Rubinstein, P. Sternberg

We compute the phase transition curves for mesoscopic superconductors. Special emphasis is given to the limiting shape of the curve when the magnetic flux is large. We derive an asymptotic formula for the ground state of the Schrödinger equation in the presence of large applied flux. The expansion is shown to be sensitive to the smoothness of the domain. The

O. Malis, K. F. Ludwig,, W. Schweika, G. E. Ice

The temperature dependence of the diffuse scattering fine structure from disordered equiatomic CuAu was studied using {\it in situ} x-ray scattering. In contrast to Cu$_3$Au the diffuse peak splitting in CuAu was found to be relatively insensitive to temperature. Consequently, no evidence for a divergence of the antiphase length-scale at the transition tempe

Oron Zachar

We Show that pair hopping through a Kondo singlet give rise to a negative Josephson coupling. Thus, our calculation supports the existance of staggered pair correlations in the strong coupling limit of a one dimensional Kondo lattice.

C. Gros, W. Wenzel

An iterative procedure for the explicit construction of the nontrivial subspace of all symmetry-adapted configurations with non-zero weight in the ground-state of the infinite-dimensional Hubbard model is developed on the basis of a symmetrized representation of the transition operators on a sequence of Bethe-Lattices of finite depth. The relation ship betwe

D. Lima, P. Borckmans, G. Dewel

We investigate the propagation of zero sound in two-species interpenetrating Bose-Einstein condensates. In very elongated clouds, this propagation is shown to be essentially one-dimensional. We also present 1D numerical experiments that exhibit the existence of two different sound pulses with velocities consistent with the theoretical predictions.

B. Groh, S. Dietrich

We study fluids of hard rods in the vicinity of hard spherical and cylindrical surfaces at densities below the isotropic-nematic transition. The Onsager second virial approximation is applied, which is known to yield exact results for the bulk properties in the limit of infinitely thin rods. This approach requires the computation of the one-particle distribu

Ferenc Kun, Hans J. Herrmann

We investigate fracture and fragmentation of solids due to impact at low energies using a two-dimensional dynamical model of granular solids. Simulating collisions of two solid discs we show that, depending on the initial energy, the outcome of a collision process can be classified into two states: a damaged and a fragmented state with a sharp transition in

C. Djurberg, K. Jonason, P. Nordblad

Experiments on the temperature and time dependence of the response function and the field cooled magnetisation of a Cu(Mn) spin glass at temperatures below the zero field spin glass temperature are used to explore the non-equilibrium nature of the underlying spin configuration. The results imply that a certain spin configuration is imprinted on the system as

Holger Frahm, Nikita A. Slavnov

New integrable boundary conditions for integrable quantum systems can be constructed by tuning of scattering phases due to reflection at a boundary and an adjacent impurity and subsequent projection onto sub-spaces. We illustrate this mechanism by considering a gl(m<n)-impurity attached to an open gl(n)-invariant quantum chain and a Kondo spin S coupled to t

David Carpentier

Using the renormalisation group (RG) we study two dimensional electromagnetic coulomb gas and extended Sine-Gordon theories invariant under the modular group SL(2,Z). The flow diagram is established from the scaling equations, and we derive the critical behaviour at the various transition points of the diagram. Following proposal for a SL(2,Z) duality betwee

P. -A. Bares, K. Grzegorczyk

A Bethe Ansatz solution of a (modified) Hubbard chain with a Kondo impurity of arbitrary spin S at a highly symmetric line of parameter space is proposed and explored. Our results confirm the existence of a strong-coupling (line of) fixed-point(s) with ferromagnetic Kondo coupling as first hypothetized by Furusaki and Nagaosa on the basis of perturbative ren

H. K. Janssen, Ue. Kutbay, K. Oerding

Using field-theoretic renormalization group methods we calculate the equation of state for non-equilibrium systems belonging to the universality class of directed percolation (Gribov process) to second order in epsilon = 4-d. By introducing a parametric representation the result can be written to this order in a very simple form. We use our result to obtain

Girish S. Setlur, Yia-Chung Chang

Here we try and delienate the properties of the function that corresponds to fluctuations in the momentum distribution. The quantity denoted by $ N(k,k^{&#39;}) $ is quite an interesting object. It satisfies various elegant sum rules and is also quite singular in some respects. All these properties are brought out and a formal connection is found between thi

M. A. Eriksson, A. Pinczuk, B. S. Dennis, S. H. Simon

We report inelastic light scattering measurements of dispersive spin and charge density excitations in dilute 2D electron systems reaching densities less than 10^{10} cm^{-2}. In the quantum Hall state at nu=2, roton critical points in the spin inter--Landau level mode show a pronounced softening as r_s is increased. Instead of a soft mode instability predic

James Hanssen, Walter Wilcox

The dependence of the Lyapunov exponent on the closeness parameter, $ε$, in tangent bifurcation systems is investigated. We study and illustrate two averaging procedures for defining Lyapunov exponents in such systems. First, we develop theoretical expressions for an isolated tangency channel in which the Lyapunov exponent is defined on single channel passes

Andrea Rocco, Bruce J. West

It is argued that the evolution of complex phenomena ought to be described by fractional, differential, stochastic equations whose solutions have scaling properties and are therefore random, fractal functions. To support this argument we demonstrate that the fractional derivative (integral) of a generalized Weierstrass function (GWF) is another fractal funct

Tod R. Lauer

Undersampled images, such as those produced by the HST WFPC-2, misrepresent fine-scale structure intrinsic to the astronomical sources being imaged. Analyzing such images is difficult on scales close to their resolution limits and may produce erroneous results. A set of ``dithered&#39;&#39; images of an astronomical source generally contains more information

P. Goldschmidt, M. J. Kukula, L. Miller, J. S. Dunlop

We have made radio observations of 87 optically selected quasars at 5 GHz with the VLA in order to measure the radio power for these objects and hence determine how the fraction of radio-loud quasars varies with redshift and optical luminosity. The sample has been selected from the recently completed Edinburgh Quasar Survey and covers a redshift range of 0.3

S. Fredriksson, D. Enstrom, J. Hansson, S. Ekelin

We suggest that dark matter is made up of massive quark objects that have survived from the Big Bang, representing the ground state of ``baryonic&#39;&#39; matter. Hence, there was no overall phase transition of the original quark matter, but only a split-up into smaller objects. We speculate that normal hadronic matter comes about through enforced phase tra

Ulrich Lindner, Uta Fritze -- von Alvensleben, Klaus J. Fricke

We have extended our chemical and cosmological galaxy evolution model to calculate the abundance evolution for altogether 16 different elements in spiral galaxies in a chemically consistent way which is a considerable step towards a more realistic galaxy modeling. Our models well reproduce observed average HII region abundances in all spiral types. All obser

E. L. Martin, G. Basri, W. Brandner, J. Bouvier

Hubble Space Telescope NICMOS observations are presented of six brown dwarf candidates in the Pleiades open cluster. One of them, namely CFHT-Pl-18, is clearly resolved as a binary with an angular separation of 0&#34;.33. The very low density of contaminating background stars in our images and the photometry of the components support that this system is a ph

Cedric Lacey, Carlton Baugh, Shaun Cole, Carlos Frenk

Semi-analytical models of galaxy formation based on hierarchical clustering now make a wide range of predictions for observable properties of galaxies at low and high redshift. This article concentrates on 2 aspects: (1) Self-consistent modelling of dust absorption predicts a mean UV extinction A_{UV} ~ 1 mag, depending only weakly on redshift, and similar t

Tanya L. Hill, Charlene A. Heisler, Ralph Sutherland, Richard W. Hunstead

We present near-infrared spectra for a sample of galaxies with ambiguous optical emission line ratios. These galaxies fall between starbursts and Seyferts in the usual optical diagnostic diagrams. We find a similar result with the near-infrared emission line ratios, which suggests that the galaxies are composite, containing both a starburst and AGN component

E. I. Robson, L. L. Leeuw, J. A. Stevens, W. S. Holland

We present millimetre photometry and submillimetre imaging of the central core and two hotspots in the radio lobes of the galaxy Cygnus-A. For both hotspots and the central core the synchrotron spectrum continues smoothly from the radio to a frequency of 677 GHz. The spectral index of the hotspots is constant over our frequ ency range, with a spectral index

Jason X. Prochaska, Arthur M. Wolfe

We present chemical abundance measurements for 19 damped lya systems observed with HIRES on the 10m W.M. Keck Telescope. Our principal goal is to investigate the abundance patterns of the damped systems and thereby determine the underlying physical processes which dominate their chemical evolution. We place particular emphasis on gauging the relative importa

Enrique Vazquez-Semadeni

We discuss HD and MHD compressible turbulence as a cloud-forming and cloud-structuring mechanism in the ISM. Results from a numerical model of the turbulent ISM at large scales suggest that the phase-like appearance of the medium, the typical values of the densities and magnetic field strengths in the intercloud medium, as well as Larson&#39;s velocity dispe

D. Richstone

Recent surveys suggest that most or all normal galaxies host a massive black hole with 1/100 to 1/1000 of the visible mass of the spheroid of the galaxy. Various lines of argument suggest that these galaxies have merged at least once in our past lightcone, and that the black holes have also merged. This leads to a merger rate of massive black holes of about

D. Richstone, E. A. Ajhar, R. Bender, G. Bower

Black holes, an extreme consequence of the mathematics of General Relativity, have long been suspected of being the prime movers of quasars, which emit more energy than any other objects in the Universe. Recent evidence indicates that supermassive black holes, which are probably quasar remnants, reside at the centers of most galaxies. As our knowledge of the

John S. Arabadjis, Joel N. Bregman

An extremely soft X-ray excess throughout galaxy clusters has been claimed as a new feature of these sytems, with important physical implications. We have reexamined this feature in the five clusters for which it has been discussed, using the most recent X-ray absorption cross sections, X-ray data processing techniques, and a consistent set of HI data. For t

Daniel Brace, Bogdan Morariu

We calculate, using noncommutative supersymmetric Yang-Mills gauge theory, the part of the spectrum of the toroidally compactified Matrix theory which corresponds to quantized electric fluxes.

Marco Ameduri, Costas J. Efthimiou, Bogomil Gerganov

The integrability of the Bukhvostov-Lipatov four-fermion model is investigated. It is shown that the classical model possesses a current of Lorentz spin 3, conserved both in the bulk and on the half-line for specific types of boundary actions. It is then established that the conservation law is spoiled at the quantum level -- a fact that might indicate that

Adrian Kent

We describe a new classical bit commitment protocol based on cryptographic constraints imposed by special relativity. The protocol is unconditionally secure against classical or quantum attacks. It evades the no-go results of Mayers, Lo and Chau by requiring from Alice a sequence of communications, including a post-revelation verification, each of which is g

Stephen C. Creagh, Niall D. Whelan

Tunnelling from a chaotic potential well is explained in terms of a set of complex periodic orbits which contain information about the real dynamics inside the well as well as the complex dynamics under the confining barrier. These orbits are associated with trajectories which are homoclinic to a real trajectory emerging from the optimal tunnelling path. The

David Merritt

A review of elliptical galaxy dynamics, with a focus on nonintegrable models. Topics covered include torus construction; modelling axisymmetric galaxies; triaxiality; collisionless relaxation; and collective instabilities.

Michal Brhlik, Gerald J. Good, G. L. Kane

We report the first fully general numerical calculation of the neutron and electron dipole moments, including the seven significant phases. We find that there are major regions in the parameter space where none of the phases are required to be small, contrary to the conventional wisdom. The electric dipole moments (EDM&#39;s) do provide useful constraints, a

Masoud Khalkhali

The goal of this article is to relate recent developments in cyclic homology theory with the theory of operads and homotopical algebra, and hence to provide a general framework to define and study operations in cyclic homology theory.

Adrian Kent

We define cryptographic assumptions applicable to two mistrustful parties who each control two or more separate secure sites between which special relativity guarantees a time lapse in communication. We show that, under these assumptions, unconditionally secure coin tossing can be carried out by exchanges of classical information. We show also, following May

Masaki Oshikawa, Alexandre M. Zagoskin

When a finite superconductor is in contact with a 1D normal conductor, superconducting phase fluctuations lead to power-law response of the normal subsystem. As a result, the charge fluctuations on the superconductor at zero temperature have logarithmic correlator and a 1/ωpower spectrum (1/f-noise). At higher temperatures 1/ωis pushed to the high frequency

Yoichiro Nambu

The properties of a nonrelativistic charged particle in two dimensions in the presence of an arbitrary number of nonquantized magnetic fluxes are investigated in free space as well as in a uniform magnetic field. The fluxes are represented mathematically as branch points in one of the complex coordinates. It is found that in order to construct solutions, the

J. E. Avron, E. Berg, D. Goldsmith, A. Gordon

We describe an apparent puzzle in classical electrodynamics and its resolution. It is concerned with the Lorentz invariance of the classical analog of the number of photons.

M. M. Sheikh-Jabbari

Considering the scattering of massless open strings attached to a D2-brane living in the $B$ field background, we show that corresponding scattering upto the order of $\a&#39;^2$ is exactly given by the gauge theory on noncommutative background, which is characterized by the Moyal bracket.

Lamberto Rondoni, Enrico Segre

Gallavotti proposed an equivalence principle in hydrodynamics, which states that forced-damped fluids can be equally well represented by means of the Navier-Stokes equations and by means of time reversible dynamical systems called GNS. In the GNS systems, the usual viscosity is replaced by a state-dependent dissipation term which fixes one global quantity. T

Mikhail Braun, Gian Paolo Vacca

The 2nd order corrections are obtained to both forward and nonforward interaction of reggeized gluons in the octet colour channel using as a basis the bootstrap relation and a specific ansatz to solve it. The obtained forward kernel coincides with the logarithmic term plus two first non-logarithmic terms in the Pomeron 2nd order kernel. Both forward and nonf

D. A. Demir

By extending the scalar sector of the Standard Model (SM) by a U(1) singlet, we show that the electroweak symmetry breaking enables the formation of a stable, electrically neutral, colorless Q-ball which couples to the SM particle spectrum solely through the Higgs boson. This Q-ball has mainly weak and gravitational interactions, and behaves as a collection

Antoine Balan

The moduli space of holomorphic fiber bundles ${\cal M}_n(\Si)$ over a compact Riemann surface $\Si$ is considered. A formula for the regularised determinant and an other for the symplectic form at trivial bundle are proposed.

Valentina S. U. Fazio, Lachezar Komitov

We report on the alignment transition of a nematic liquid crystal from initially homeotropic to quasi-planar due to field-induced anchoring breaking. The initial homeotropic alignment is achieved by Langmuir-Blodgett monolayers. In this geometry the anchoring strength can be evaluated by the Frederiks transition technique. Applying an electric field above a

A. Abada, O. Pene, J. Rodriguez-Quintero

The interaction energy of the neutrons due to massless neutrino exchange in a neutron star has recently been proved, using an effective theory, to be extremely small and infrared-safe. Our comment here is of conceptual order: two approaches to compute the total interaction energy density have recently been proposed. Here, we study the connection between thes

M. C. Diamantini, H. Kleinert, C. A. Trugenberger

We propose a new string model by adding a higher-order gradient term to the rigid string, so that the stiffness can be positive or negative without loosing stability. In the large-D approximation, the model has three phases, one of which with a new type of generalized &#34;antiferromagnetic&#34; orientational correlations. We find an infrared-stable fixed po

Paul J. Groot, Thomas Augusteijn, Orly Barziv, Jan van Paradijs

We have obtained differential time series photometry of the cataclysmic variable GS Pavonis over a timespan of 2 years. These show that this system is deeply eclipsing (~2-3.5 mag) with an orbital period of 3.72 hr. The eclipse depth and out-of-eclipse light levels are correlated. From this correlation we deduce that the disk radius is changing and that the

Antonio L. Maroto

We study the production of massive fermions in arbitrary vector and axial-vector classical backgrounds using effective action techniques. A perturbative calculation shows the different features of each field and in particular it is seen that pure temporal axial fields can produce particles whereas it is not possible for a pure vector background. We also anal

J. S. Thakur, D. Neilson

We investigated the interdependence of the effects of disorder and carrier correlations on the metal-insulator transition in two-dimensional electronic systems. We present a quantitative metal-insulator phase diagram. Depending on the carrier density we find two different types of metal-insulator transition - a continuous localization for rs=<8 and a discont

Roberto Casadio

An attempt is made to go beyond the standard semi-classical approximation for gravity in the Born-Oppenheimer decomposition of the wave-function in minisuperspace. New terms are included which correspond to quantum gravitational fluctuations on the background metric. Their existence renders the definition of the semi-classical limit rather delicate and can l

I. Kh. Zharekeshev, B. Kramer

The level spacing distribution is numerically calculated at the disorder-induced metal--insulator transition for dimensionality d=4 by applying the Lanczos diagonalisation. The critical level statistics are shown to deviate stronger from the result of the random matrix theory compared to those of d=3 and to become closer to the Poisson limit of uncorrelated

S. Bonazzola, E. Gourgoulhon, J. -A. Marck

We report on general relativistic calculations of quasiequilibrium configurations of binary neutron stars in circular orbits with zero vorticity. These configurations are expected to represent realistic situations as opposed to corotating configurations. The Einstein equations are solved under the assumption of a conformally flat spatial 3-metric (Wilson-Mat

Rong-Gen Cai

In the multihorizon black hole spacetimes, it is possible that there are degenerate Cauchy horizons with vanishing surface gravities. We investigate the stability of the degenerate Cauchy horizon in black hole spacetimes. Despite the asymptotic behavior of spacetimes (flat, anti-de Sitter, or de Sitter), we find that the Cauchy horizon is stable against the

Nikita Nekrasov

We study BPS states which arise in compactifications of M-theory on Calabi-Yau manifolds. In particular, we are interested in the spectrum of the particles obtained by wrapping M2-brane on a two-cycle in the CY manifold X. We compute the Euler characteristics of the moduli space of genus zero curves which land in a holomorphic four-cycle $S \subset X$. We us

S. M. Maurer, S. R. Patel, C. M. Marcus, C. I. Duruoz

Quantum fluctuations of Coulomb blockade are investigated as a function of the coupling to reservoirs in semiconductor quantum dots. We use fluctuations in the distance between peaks $ΔN$ apart to characterize both the amplitude and correlation of peak motion. For strong coupling, peak motion is greatly enhanced at low temperature, but does not show an incre

Kei-Ichi Kondo

We give another derivation of quark confinement in QCD from the viewpoint of the low-energy effective Abelian gauge theory of QCD obtained via Abelian projection. It is based on the recently discovered Berezinskii-Kosterlitz-Thouless phase transition in the four-dimensional Abelian gauge theory. Moreover, we show that there exists a critical gauge coupling c

J. Borissova, M. Catelan, F. R. Ferraro, N. Spassova

Deep BV photometry for a large field covering the outer-halo globular cluster NGC 6229 is presented. For the first time, a colour-magnitude diagram (CMD) reaching below the main sequence turnoff has been obtained for this cluster. Previous results regarding the overall morphology of the horizontal and giant branches are confirmed. In addition, nine possible

Antoine Balan

The Lax operators of the Benney type equations are studied on the circle. The vectors fields of the Lax operators are showed to commute with each other

Michael Butler, Pieter Hartel

Grover&#39;s search algorithm is designed to be executed on a quantum mechanical computer. In this paper, the probabilistic wp-calculus is used to model and reason about Grover&#39;s algorithm. It is demonstrated that the calculus provides a rigorous programming notation for modelling this and other quantum algorithms and that it also provides a systematic f

Arnolds Kikusts

We study 1-way quantum finite automata (QFAs) and compare them with their classical counterparts. We show that 1-way QFAs can be very space efficient. We construct a 1-way QFAs that are quadratically smaller than any equivalent deterministic finite automata and give the correct answer with a large probability by recognizing the languages in a two letter alph

Ali Mostafazadeh

For a periodic Hamiltonian, periodic dynamical invariants may be used to obtain non-degenerate cyclic states. This observation is generalized to the degenerate cyclic states, and the relation between the periodic dynamical invariants and the Floquet decompositions of the time-evolution operator is elucidated. In particular, a necessary condition for the occu

Jing-ye Zhang, Yang Sun, Mike Guidry, L. L. Riedinger

A new Nilsson single-particle structure is proposed for neutron-rich nuclei near $^{132}$Sn. In general, a large reduction in spin-orbit interaction is required and the neutron $N = 82$ gap persists in the new set of parameters. The ground state deformations for several isotopic chains are studied with this set and compared with the results of the standard s

Gerhard Rein

We prove the existence of static, spherically symmetric solutions of the stellar dynamic Vlasov-Poisson and Vlasov-Einstein systems, which have the property that their spatial support is a finite, spherically symmetric shell with a vacuum region at the center.

Gerhard Rein

We consider a special case of the three dimensional Vlasov-Poisson system where the particles are restricted to a plane, a situation that is used in astrophysics to model extremely flattened galaxies. We prove the existence of steady states of this system. They are obtained as minimizers of an energy-Casimir functional from which fact a certain dynamical sta

Roger Fenn, Colin Rourke

We study equations over torsion-free groups in terms of their `t-shape&#39; (the occurences of the variable t in the equation). A t-shape is good if any equation with that shape has a solution. It is an outstanding conjecture that all t-shapes are good. In [Klyachko&#39;s methods and the solution of equations over torsion-free groups, l&#39;Enseign. Maths. 4

J. Brian Conrey, Henryk Iwaniec

The authors study the central values of L-functions in certain families; in particular they bound the sum of the cubes of these values.Contents:

B. G. Konopelchenko, G. Landolfi

Extensions of the generalized Weierstrass representation to generic surfaces in 4D Euclidean and pseudo-Euclidean spaces are given. Geometric characteristics of surfaces are calculated. It is shown that integrable deformations of such induced surfaces are generated by the Davey -Stewartson hierarchy. Geometrically these deformations are characterized by the

Vu Ngoc San

We present a detailed study, in the semi-classical regime $h \to 0$, of microlocal properties of systems of two commuting h-PDO s $P_1(h)$, $P_2(h)$ such that the joint principal symbol $p=(p_1,p_2)$ has a special kind of singularity called a &#34;focus-focus&#34; singularity. Typical examples include the quantum spherical pendulum or the quantum Champagne b

A. Pajitnov

Let M be a closed connected manifold. Let m(M) be the Morse number of M, that is, the minimal number of critical points of a Morse function on M. Let N be a finite cover of M of degree d. M.Gromov posed the following question: what are the asymptotic properties of m(N) as d goes to infinity? In this paper we study the case of high dimensional manifolds M wit

Amnon Yekutieli

Two rings A and B are said to be derived Morita equivalent if their derived categories of modules are equivalent. By results of Rickard, if A and B are derived Morita equivalent algebras over a field k, then there is a complex of bimodules T s.t. the derived tensor product with T is an equivalence. The complex T is called a tilting complex. When B = A the is

R. Percacci, E. Sezgin

Nonlinear sigma models arise in supergravity theories with or without matter couplings in various dimensions and they are important in understanding the duality symmetries of M-theory. With this motivation in mind, we review the salient features of gauged and ungauged nonlinear sigma models with or without Wess-Zumino terms for general target spaces in a min

S. Bellucci

We study the unscreened Coulomb interaction in a one-dimensional electron system at low-energy. We use renormalization group methods and a GW approximation, in order to analyze the model. This yields both a strong wavefunction renormalization and a renormalization of the Fermi velocity. The significance of the effects depends on the filling level of the Ferm

R. Argurio, L. Houart

We study aspects of the new phases of M-theory recently conjectured using generalised dualities such as timelike T-duality. Our focus is on brane solutions. We derive the intersection rules in a general framework and then specialise to the new phases of M-theory. We discuss under which conditions a configuration with several branes leads to a regular extrema

Brandon Carter

It has recently been shown how the effect of the divergent part of the gravitational self interaction for a classical string model in 4 dimensions can be allowed for by a renormalisation of its stress energy tensor and in the elastic case a corresponding renormalisation of the off shell action. It is shown here that that it is possible to construct a new cat

G. C. Rossi

In the language of Feynman path integrals the quantization of gauge theories is most easily carried out with the help of the Schrödinger Functional (SF). Within this formalism the essentially unique gauge fixing condition is $A_{\circ} = 0$ (temporal gauge), as any other rotationally invariant gauge choice can be shown to be functionally equivalent to the fo

Tomasz Brzezinski, Cezary Gonera, Pawel Maslanka

The canonical transformation and its unitary counterpart which relate the rational Calogero-Moser system to the free one are constructed.

Yves Brihaye, Claude Gabriel

A non-linear sigma model mimicking the Skyrme model on S_3 is proposed and a family of classical solutions to the equations are constructed numerically. The solutions terminate into catastrophe-like spikes at critical values of the Skyrme coupling constant and, when this constant is zero, they coincide with the series of Harmonic maps on S_3 constructed some

Gianpiero Mangano

We discuss a path integral formalism to introduce noncommutative generalizations of spacetime manifold in even dimensions, which have been suggested to be reasonable effective pictures at very small length scales, of the order of Planck length.

M. Hortacsu, K. Ulker

We study two constrained scalar models. While there seems to be equivalence when the partially integrated Feynman path integral is expanded graphically, the dynamical behaviour of the two models are different when quantization is done using Dirac constraint analysis.

Jean-Loup Gervais

Characters of $E_8\otimes E_8$ and SO(32) heterotic strings involving the full internal symmetry Cartan subalgebra generators are defined after circle compactification so that they are T dual. The novel point, as compared with an earlier study of the type II case (hep-th/9707107), is the appearence of Wilson lines. Using SO(17,1) transformations between the

J. Ambjørn, Yu. M. Makeenko, G. W. Semenoff

We examine the matrix theory representation of D0-brane dynamics at finite temperature. In this case, violation of supersymmetry by temperature leads to a non-trivial static potential between D0-branes at any finite temperature. We compute the static potential in the 1-loop approximation and show that it is short-ranged and attractive. We compare the result

Won Tae Kim

We calculate the statistical entropy of a scalar field on the background of three-dimensional De Sitter space in terms of the brick wall method and finally derive the perimeter law of the entropy.

Toyoki Matsuyama

We investigate the canonical structure of the (2+1)-dimensional non-linear $σ$ model in a $polynomial$ formulation. A current density defined in the non-linear $σ$ model is a vector field which satisfies a $formal$ flatness (or pure gauge) condition. It is the polynomial formulation in which the vector field is regarded as a dynamical variable on which the f

H. Lu, C. N. Pope, K. S. Stelle

We study the duality relationship between M-theory and heterotic string theory at the classical level, emphasising the transformations between the Kaluza-Klein reductions of these two theories on the K3 and T^3 manifolds. Particular attention is devoted to the corresponding structures of sigma-model cosets and the correspondence between the p-brane charge la

G. E. A. Matsas, J. C. Montero, V. Pleitez, D. A. T. Vanzella

We argue in favor of the existence of the LIPs, the least interacting particles, which would only interact with ordinary matter through gravitational field and could account for (at least) part of the dark matter. The detectability of LIP matter is addressed at the end.

Ja. V. Burdanov, G. V. Efimov, S. N. Nedelko

The transition form factor, decay width and charge form factor of pion are calculated within the model of induced nonlocal quark currents based on the assumption that the nonperturbative QCD vacuum can be characterized by a homogeneous (anti-)self-dual gluon field. It is shown that the interaction of the quark spin with the vacuum gluon field, being responsi

S. Schmidt, D. Blaschke, G. Ropke, A. V. Prozorkevich

We analyze a quantum kinetic equation describing both boson and fermion pair production and explore analytically and numerically the solution of the non-Markovian kinetic equation. In the Markovian limit of the kinetic equation we find an analytical solution for the single particle distribution function of bosons and fermions. The numerical investigation for

Y. -Y. Keum

We summerize the status of factorization hypothesis in the color-suppressed B meson decays : $B \to J/ψK^{(*)}$. We present the general formalism for decay rates and polarization fractions with considering all possible non-factorizable contributions which also include the color-octet contributions, and a new factorization scheme comes appear when the univers

G. Kramer, B. Pötter

We review next-to-leading order calculations of one- and two-jet production in ep collisions at HERA for photon virtualities in the range 1<Q^2<100 GeV^2. Soft and collinear singularities are extracted using the phase space slicing method. Numerical results are presented for HERA conditions with the Snowmass jet definition. The transition between photoproduc

Probir Roy

The radiative model, proposed by Zee, is extended from the three neutrino $(ν_{e,μ,τ})$ sector to include a fourth sterile neutrino $ν_s$. The oscillations $ν_e \leftrightarrow ν_s$ (solar), $ν_μ\leftrightarrow ν_τ$ (atmospheric) and $ν_e \leftrightarrow ν_μ$ (LSND) are invoked to explain all oscillation data with the successful relation $(Δm^2)_{atm} \simeq

A. Giovannini, R. Ugoccioni

Possible scenarios in hh collisions in the TeV regions are discussed in full phase space. It is shown that at such high energies one should expect strong KNO scaling violation and a ln(s) increase of the average charged multiplicity of the semi-hard component, resulting in a huge mini-jet production.

Jan -e Alam, Abhijit Bhattacharyya, Sanjay K. Ghosh, Sibaji Raha

We present a microscopic approach to dynamical pionisation of the hot quark-gluon matter formed in ultrarelativistic heavy ion collisions. The time evolution of the system is described assuming that quarks undergo Brownian motion in a thermal bath provided by the gluons. The rate of hadronization as well as the time dependence of the temperature of the syste

S. Hino, M. Hirai, S. Kumano, M. Miyama

We discuss transversity distributions and transverse spin asymmetries. First, $Q^2$ evolution results are shown for transversity and longitudinally polarized distributions. Second, the antiquark flavor asymmetry $Δ_{_T} \bar u/Δ_{_T} \bar d$ is discussed in two different descriptions, a meson-cloud model and an exclusion model. Both calculations produce a si

B. Dutta, R. N. Mohapatra, D. J. Muller

We analyze the signal at the Tevatron for the doubly charged Higgs superfield of supersymmetric left-right models with gauge mediated supersymmetry breaking. Due to the presence of a new coupling, the lighter stau is usually less massive than the lightest neutralino and is frequently the NLSP. The fermionic part of the doubly charged Higgs field decays domin

Y. -Y. Keum

We calculate the decay constant of $D_s$ and $D_s^{*}$ with $\bar{B}^0 \ra D^{+}\ell^{-}ν$ and $\bar{B}^0 \ra D^{+}D_s^{-(*)}$ decays. In our analysis we assume that factorization ansatz works and used two different form factor behaviours (constant and monopole-type) for $F_0(q^2)$. We also consider the QCD-penguin contributions in hadronic decays within the

Johann Rafelski, H. -Thomas Elze

Quarks play an active role in shaping the QCD vacuum structure. Being dual carriers of both `color&#39; and `electric&#39; charges they also respond to externally applied electromagnetic fields. Thus, in principle, the vacuum of strong interactions influences higher order QED processes such as photon-photon scattering. We survey here the current status of th