April 1998 arXiv papers — page 17

I. Ya. Aref'eva, A. S. Koshelev, P. B. Medvedev

Classical dynamics in SU(2) Matrix theory is investigated. A classical chaos-order transition is found. For the angular momentum small enough (even for small coupling constant) the system exhibits a chaotic behavior, for angular momentum large enough the system is regular.

A. Gorsky

We discuss the meaning of a Casher-Banks relation for the Dirac operator eigenvalues in MQCD. It suggests the interpretaion of the eigenvalue as a coordinate involved in the brane configuration.

Irina Ya. Aref'eva, Gabriele Ferretti, Alexey S. Koshelev

We show how to reduce the non abelian Born-Infeld action describing the interaction of two D-particles to the sum of elliptic integrals depending on simple kinematic invariants. This representation gives explicitly all alpha' corrections to D-particle dynamics. The alpha' corrections induce a stabilization of the classical trajectories such as the ``

F. Benatti, R. Floreanini

We use (nonconservative) dynamical semigroups to investigate the decay law of a quantum unstable system weakly coupled with a large environment. We find that the deviations from the classical exponential law are small and can be safely ignored in any actual experiment.

Pietro Antonio Grassi

In this paper we study the Abelian Anti-ghost equation for the Standard Model quantized in the 't Hooft-Background gauge. We show that this equation assures the non-renormalization of the abelian ghost fields and prevents possible abelian anomalies.

D. Oliva Agüero, H. Pérez Rojas, A. Pérez Martínez, A. Amézaga Hechavarría

We discuss the gauge parameter dependence of particle spectra in statistical quantum electrodynamics and conclude that the electron spectrum is gauge-parameter dependent. The physical spectrum being obtained in the Landau gauge, which leads to gauge invariance in a restricted class of gauge transformations.

Harry J. Lipkin

Studying scattering of heavy flavor hadrons and looking for bound states is shown to give experimental information otherwise unobtainable about effective two-body interactions between constituent $(qq)_6$ and $(\bar qq)_8$ pairs respectively in color sextet and color octet states. All the successes of the constituent quark model in $(uds)$ hadron spectroscop

A. Hebecker, H. Weigert

A simple and intuitive calculation, based on the semiclassical approximation, demonstrates how the large size of a hadronic target introduces a new perturbative scale into the process of small-x deep inelastic scattering. The above calculation, which is performed in the target rest frame, is compared to the McLerran-Venugopalan model for scattering off large

Andrzej Czarnecki, Kirill Melnikov

We present complete O(alpha_s^2) corrections to the decay b-->c+l+nu at the point where the invariant mass of the leptons sqrt{q^2} equals the c quark mass. We use this result, together with previously obtained corrections at the ends of the q^2 spectrum, to estimate the total width of the semileptonic b-->c decay with O(alpha_s^2) accuracy, essential for th

J. R. Espinosa, A. Riotto, G. G. Ross

An inflationary stage dominated by a $D$-term avoids the slow-roll problem of inflation in supergravity and may emerge in theories with a non-anomalous or anomalous U(1) gauge symmetry. The most intriguing and commonly invoked possibility is that the Fayet-Iliopoulos $D$-term triggering inflation is the one emerging in superstring theories. We discuss the co

R. Baier, Yu. L. Dokshitzer, A. H. Mueller, D. Schiff

We extend the BDMPS formalism for calculating radiative energy loss to the case when the radiated gluon carries a finite fraction of the quark momentum. Some virtual terms, previously overlooked, are now included. The equivalence between the formalism of BDMPS and that of B.Zakharov is explicitly demonstrated.

G. Montagna, O. Nicrosini, G. Passarino, F. Piccinini

The program TOPAZ0 was developed for computing a variety of physical observables which are related to the e+e- annihilation into fermion pairs and to the large angle Bhabha scattering around the Z resonance. Among them, the Z parameters or pseudo-observables, the de-convoluted cross sections and those dressed with QED radiation, and finally the forward-backw

H. -J. He

We review the recent progress in studying the anomalous electroweak quartic gauge boson couplings (QGBCs) at the LHC and the next generation high energy e+-e- linear colliders (LCs). The main focus is put onto the strong electroweak symmetry breaking scenario in which the non-decoupling guarantees sizable new physics effects for the QGBCs. After commenting u

J. A. Oller, E. Oset, J. R. Pelaez

A non-perturbative method which combines constraints from chiral symmetry breaking and coupled channel unitarity is used to describe the meson-meson interaction up to about 1.2 GeV. The approach uses the O(p^2) and O(p^4) chiral Lagrangians. The seven free parameters of the O(p^4) Lagrangian are fitted to the data. The results are in good agreement with a va

Werner Porod

We discuss the phenomenology of third generation sfermions paying particular attention to the implications of the Yukawa couplings and to the left-right mixing. Analytical formulae are given for the sfermion mixing, the production cross sections at e+e- colliders, and for all possible two body decay widths that can occur at tree level. In case of the light s

N. I. Kochelev, A. De Roeck

A new mechanism for an increased event production in the large $Q^2$, $x$ region at HERA is suggested. This mechanism results from a new type of instanton-induced quark-quark interaction, which is related to non-zero quark modes in the instanton field. We estimate the contribution of this interaction to the valence quark structure function $F_2^v$ using the

M. N. Chernodub, M. I. Polikarpov, A. I. Veselov, M. A. Zubkov

We investigate numerically the properties of the Abrikosov-Nielsen-Olesen strings in 4D abelian Higgs model. The fractal dimension D_f of the vortex strings was found to be large in the Coulomb phase and it is close to 2 in the Higgs phase. We also show that the Wilson loop for non-integer charges is correlated with the linking number of the vortex string wo

M. N. Achasov, A. V. Bozhenok, A. D. Bukin, D. A. Bukin

Results from the Spherical Nonmagnetic Detector (SND) on $Δ(1232)$ isobar electroproduction in the collisions of beam electrons (positrons) and residual gas nuclei in the VEPP-2M $e^+e^-$ collider are presented. On the basis of the obtained data the expected counting rate of this process in future high luminosity $e^+e^-$ colliders (~$ϕ$-, $c$-$τ$- and $b$-f

Jean-Pierre Luminet

In the first part I set out some unexplored historical material about the early development of cosmic topology. In the second part I briefly comment new developments in the field since the Lachieze-Rey & Luminet report (1995), both from a theoretical and an observational point of view.

I. B. Khriplovich

A simple argument is presented in favour of the equidistant spectrum in semiclassical limit for the horizon area of a black hole. The following quantization rules for the mass $M_N$ and horizon area $A_{Nj}$ are proposed: M_N = m_p [N(N+1)]^{1/4}; A_{Nj} = 8πl_p^2 [\sqrt{N(N+1)} + \sqrt{N(N+1) - j(j+1)} ]. Here both $N$ and $j$ are nonnegative integers or ha

Hideki Asada

We present a formulation for the internal motion of equilibrium configurations with a rotational Killing vector in general relativity. As an approximation, this formulation is applicable to investigation of the internal motion of quasi-equilibrium configurations such as binary neutron stars. Based on this simple formulation, a condition for the general relat

Marco Marani, Jayanth R. Banavar, Guido Caldarelli, Amos Maritan

We study the stationary state of a Poisson problem for a system of N perfectly conducting metal balls driven by electric forces to move within a medium of very low electrical conductivity onto which charges are sprayed from outside. When grounded at a confining boundary, the system of metal balls is experimentally known to self-organize into stable fractal a

M. Bahiana, W. A. M. Morgado

The microphase separation of a diblock copolymer melt confined by hard walls and in the presence of a gravitational field is simulated by means of a cell dynamical system model. It is found that the presence of hard walls normal to the gravitational field are key ingredients to the formation of well ordered lamellae in BCP melts. To this effect the currents

Pier Luigi Silvestrelli, Nicola Marzari, David Vanderbilt, Michele Parrinello

We use the maximally-localized Wannier function method to study bonding properties in amorphous silicon. This study represents, to our knowledge, the first application of the Wannier-function analysis to a disordered system. Our results show that, in the presence of disorder, this method is extremely helpful in providing an unambiguous picture of the bond di

Avraham Cohen, Klaus Richter, Richard Berkovits

Using the self--consistent Hartree-Fock approximation for electrons with spin at zero temperature, we study the effect of the electronic interactions on the charge distribution in a one-dimensional continuous ring containing a single $δ$ scatterer. We reestablish that the interaction suppresses the decay of the Friedel oscillations. Based on this result, we

E. Marinari, G. Parisi, F. Ricci-Tersenghi, J. J. Ruiz-Lorenzo

We compute numerically small window overlaps in the three dimensional Edwards Anderson spin glass. We show that they behave in the way implied by the Replica Symmetry Breaking Ansatz, that they do not qualitatively differ from the full volume overlap and do not tend to a trivial function when increasing the lattice volume. On the contrary we show they are af

Attilio L. Stella, Giovanni Sartoni

Replica and functional renormalization group methods show that, with short range substrate forces or in strong fluctuation regimes, wetting of a self-affine rough wall in 2D turns first-order as soon as the wall roughness exponent exceeds the anisotropy index of bulk interface fluctuations. Different thresholds apply with long range forces in mean field regi

Paolo Tommasini, Eddy Timmermans, Mahir Hussein, Arthur Kerman

The interactions responsible for Feshbach resonances in binary atom collisions produce a condensate of molecules in the atomic BEC-system. We discuss the `ground state' of the condensate system and illustrate that its properties differ quantitatively and qualitatively from the properties of a single condensate with atom-atom interactions described by the

S. Goedecker

Using ordinary Fourier analysis, the asymptotic decay behavior of the density matrix F(r,r') is derived for the case of a metal at a finite electronic temperature. An oscillatory behavior which is damped exponentially with increasing distance between r and r' is found. The decay rate is not only determined by the electronic temperature, but also by t

J. Tworzydlo, O. Y. Osman, C. N. A. van Duin, Jan Zaanen

It is argued that the spin dynamics in the charge-ordered stripe phase might be revealing with regards to the nature of the anomalous spin dynamics in cuprate superconductors. Specifically, if the stripes are bond ordered much of the spin fluctuation will originate in the spin sector itself, while site ordered stripes require the charge sector as the driving

P. R. C. Kent, Randolph Q. Hood, M. D. Towler, R. J. Needs

Quantum Monte Carlo (QMC) techniques are used to calculate the one-body density matrix and excitation energies for the valence electrons of bulk silicon. The one-body density matrix and energies are obtained from a Slater-Jastrow wave function with a determinant of local density approximation (LDA) orbitals. The QMC density matrix evaluated in a basis of LDA

John Larcheveque

Graph Interpolation Grammars are a declarative formalism with an operational semantics. Their goal is to emulate salient features of the human parser, and notably incrementality. The parsing process defined by GIGs incrementally builds a syntactic representation of a sentence as each successive lexeme is read. A GIG rule specifies a set of parse configuratio

E. V. Gotthelf, G. Vasisht

We report the serendipitous discovery of a 7-s X-ray pulsar using data acquired with the Advanced Satellite for Cosmology and Astrophysics. The pulsar is detected as an unresolved source located towards a region of the Galactic plane (l,b ~ 29.5, 0.08) that coincides with an overdensity of star-formation tracers. The signal suffers tremendous foreground abso

A. Lazarian

Understanding the properties of interstellar turbulence is a great intellectual challenge and the urge to solve this problem is partially motivated by a necessity to explain the star formation mystery. This review deals with a recently suggested inversion technique as applied to atomic hydrogen. This technique allows to determine 3D turbulence statistics thr

Eli Waxman

Annihilation of high energy, $\sim 10^{21}$eV, neutrinos on big bang relic neutrinos of $\sim 1$eV mass, clustered in the Galactic halo or in a nearby galaxy cluster halo, has been suggested to generate, through hadronic Z decay, high energy nucleons and photons which may account for the detected flux of >10^{20}eV cosmic-rays. We show that the flux of high

M. Bobrowsky, K. C. Sahu, M. Parthasarathy, P. Garcia-Lario

The final expulsion of gas by a star as it forms a planetary nebula --- the ionized shell of gas often observed surrounding a young white dwarf --- is one of the most poorly understood stages of stellar evolution. Such nebulae form extremely rapidly (about 100 years for the ionization) and so the formation process is inherently difficult to observe. Particul

Noah Brosch, Ana Heller, Elchanan Almoznino

We explore mechanisms for the regulation of star formation in dwarf galaxies. We concentrate primarily on a sample in the Virgo cluster, which has HI and blue total photometry, for which we collected H$α$ data at the Wise Observatory. We find that dwarf galaxies do not show the tight correlation of the surface brightness of H$α$ (a star formation indicator)

A. Boselli, J. Lequeux, M. Sauvage, O. Boulade

We analyse the integrated properties of the Mid-IR emission of a complete, optically selected sample of galaxies in the Virgo cluster observed with the ISOCAM instrument on board the ISO satellite. The analysis shows that the Mid-IR emission up to 15 mic of optically-selected, normal early-type galaxies (E, S0 and S0a) is dominated by the Rayleigh-Jeans tail

Katrina M. Sealey, Michael J. Drinkwater, John K. Webb

The Hubble Deep Field South (HDF-S) HST observations are expected to begin in October 1998. We present a composite spectrum of the QSO in the HDF-S field covering UV/optical/near IR wavelengths, obtained by combining data from the ANU 2.3m Telescope with STIS on the HST. This intermediate resolution spectrum covers the range 1600-10000A and allows us to deri

Noam Soker

I summarize some recent models and ideas for the formation of axisymmetrical structures of planetary nebulae and the three rings of SN 1987A, as follows. (a) I review the general role of binary companions, including brown dwarfs and planets. (b) I propose a mechanism for axisymmetrical mass loss on the AGB that may account for the axially symmetric structure

A. F. Boden, G. T. van Belle, The PTI Collaboration

We report on a near-infrared, long-baseline interferometric search for luminous companions to the star 51 Pegasi conducted with the Palomar Testbed Interferometer. Our data is completely consistent with a single-star hypothesis. We find no evidence to suggest a luminous companion to 51 Pegasi, and can exclude a companion brighter than a $Δ$K of 4.27 at the 9

Limin Wang, Paul J. Steinhardt

The abundance of rich clusters is a strong constraint on the mass power spectrum. The current constraint can be expressed in the form $σ_8 Ω_m^γ = 0.5 \pm 0.1$ where $σ_8$ is the $rms$ mass fluctuation on 8 $h^{-1}$ Mpc scales, $Ω_m$ is the ratio of matter density to the critical density, and $γ$ is model-dependent. In this paper, we determine a general expr

Chris Adami, Ryoichi Seki, Robel Yirdaw

We analyze the geometry of the species- and genotype-size distribution in evolving and adapting populations of single-stranded self-replicating genomes: here programs in the Avida world. We find that a scale-free distribution (power law) emerges in complex landscapes that achieve a separation of two fundamental time scales: the relaxation time (time for popu

F. Gonzalez-Rey, M. Rocek

The effective action of N=2 gauge multiplets in general includes higher-dimension UV finite nonholomorphic corrections integrated with the full N=2 superspace measure. By adding a hypermultiplet in the adjoint representation we study the effective action of N=4 SYM. The nonanomalous SU(4) R-symmetry of the classical N=4 theory must be also present in the on-

V. V. Khoze, M. P. Mattis, M. J. Slater

We present a compendium of results for ADHM multi-instantons in SU(N) SUSY gauge theories, followed by applications to N=2 supersymmetric models. Extending recent SU(2) work, and treating the N=1 and N=2 cases in parallel, we construct: (i) the ADHM supermultiplet, (ii) the multi-instanton action, and (iii) the collective coordinate integration measure. Spec

Henric Rhedin, Howard J. Schnitzer

The renormalization group flows of the coupling constants for the gauged U(N) vector model, with N_f massless fermions in the defining representation, are studied in the large N limit, to all orders in the scalar coupling lambda, leading order in 1/N, and lowest two orders in the gauge coupling g^2. It is shown that the restrictions of asymptotic freedom, an

Philip C. Argyres, Alex Buchel

S-dualities in scale invariant N=2 supersymmetric field theories with product gauge groups are derived by embedding those theories in asymptotically free theories with higher rank gauge groups. S-duality transformations on the couplings of the scale invariant theory follow from the geometry of the embedding of the scale invariant theory in the Coulomb branch

A. I. Sokolov, E. V. Orlov

The field-theoretical renormalization group approach is used to estimate the universal critical value g_6^* of renormalized sextic coupling constant for the two-dimensional Ising model. Four-loop perturbative expansion for g_6 is calculated and resummed by means of the Pade-Borel-Leroy technique. Under the optimal value of the shift parameter b providing the

J. C. Nacher, E. Oset

We have extended a model for the $γN\to ππN$ reaction to virtual photons and selected the diagrams which have a $Δ$ in the final state. With this model we have evaluated cross sections for the virtual photon cross section as a function of $Q^2$ for different energies. The agreement found with the $γ_v p\toΔ^0π^+$ and $γ_v p\toΔ^{++}π^-$ reactions is good. Th

E. Epelbaoum, W. Glöckle, Ulf-G. Meißner

Starting from a precise two-nucleon potential, we use the method of unitary transformations to construct an effective potential that involves only momenta less than a given maximal value. We describe this method for an S-wave potential of the Malfliet-Tjon type. It is demonstrated that the bound and scattering state spectrum calculated within the effective t

Holger F. Hofmann, Ortwin Hess

The amplified spontaneous emission spectrum of the light field in the non-lasing supermode of two coupled semiconductor lasers is analyzed using linearized Langevin equations. It is shown that the interference betweeen the laser mode and the fluctuating light field in the non-lasing mode causes spatial holeburning. This effect introduces a phase sensitive co

Cenalo Vaz, Louis Witten

In the final stages of collapse, quantum radiation due to particle creation from a naked singularity is expected to be significantly different from black hole radiation. In certain models of collapse it has been shown that, neglecting the back reaction of spacetime, the particle flux on future null infinity grows as the inverse square of the distance from th

V. A. Khoze, T. Sjöstrand

Cross-talk between the W^+ and W^- sources of hadron production at LEP2 offers a hope to learn about basic properties of QCD, but at the same time threatens high-precision measurements of the W boson mass. Directly visible effects are not expected to be large, however. It is, therefore, important to develop methods to measure the level of interconnection in

Stephen Hwang, Robert Marnelius, Panagiotis Saltsidis

We propose a new general BRST approach to string and string-like theories which have a wider range of applicability than e g the conventional conformal field theory method. The method involves a simple general regularization of all basic commutators which makes all divergent sums to be expressible in terms of zeta functions from which finite values then may

Joseph C. Varilly, Jose M. Gracia-Bondia

By exploiting the relation between Fredholm modules and the Segal-Shale-Stinespring version of canonical quantization, and taking as starting point the first-quantized fields described by Connes' axioms for noncommutative spin geometries, a Hamiltonian framework for fermion quantum fields over noncommutative manifolds is introduced. We analyze the ultrav

D. Alves, C. Alcock, K. Cook, S. Marshall

This paper has been withdrawn by the author.

R. Baptista, K. Horne, R. A. Wade, I. Hubeny

Time-resolved eclipse spectroscopy of the nova-like variable UX UMa obtained with the HST/FOS on 1994 August and November is analyzed with eclipse mapping techniques to produce spatially resolved spectra of its accretion disc and gas stream as a function of distance from disc centre. The inner accretion disc is characterized by a blue continuum filled with a

Kaspar von Braun, Kristin Chiboucas, Jocelyn Kelly Minske, Jose Francisco Salgado

New Johnson-Cousins UBVRI photometry of giants in globular clusters is combined with JHK photometry on the CIT system to produce color sequences for giants from the globular clusters M3, M5, M13, and M92. UBVRI data are also presented for giants in the metal-rich open cluster NGC 6791. These data fill a gap in the literature, especially for the R & I bands.

G. Moore, N. Nekrasov, S. Shatashvili

We compute the principal contribution to the index in the supersymmetric quantum mechanical systems which are obtained by reduction to 0+1 dimensions of $\mathcal{N}=1$, $D=4,6,10$ super-Yang-Mills theories with gauge group SU(N). The results are: ${1\over{N^{2}}}$ for $D=4,6$, $\sum_{d | N} {1\over{d^{2}}}$ for D=10. We also discuss the D=3 case.

Boris A. Kupershmidt

Heisenberg motion equations in Quantum mechanics can be put into the Hamilton form. The difference between the commutator and its principal part, the Poisson bracket, can be accounted for exactly. Canonical transformations in Quantum mechanics are not, or at least not what they appear to be; their properties are formulated in a series of Conjectures.

Oleg V. Prezhdo, Peter J. Rossky

A relationship between the time scales of quantum coherence loss and short-time solvent response for a solute/bath system is derived for a Gaussian wave packet approximation for the bath. Decoherence and solvent response times are shown to be directly proportional to each other, with the proportionality coefficient given by the ratio of the thermal energy fl

Arun K. Pati

We establish a fluctuation-correlation theorem by relating the quantum fluctuations in the generator of the parameter change to the time integral of the quantum correlation function between the projection operator and force operator of the ``fast'' system. By taking a cue from linear response theory we relate the quantum fluctuation in the generator

Lars M. Johansen

A conditional kinetic energy is defined in terms of the Wigner distribution. It is shown that this kinetic energy may become negative for negative Wigner distributions. A free particle wave packet with negative kinetic energy will spread in a nonclassical manner.

R. F. Werner

We construct the unique optimal quantum device for turning a finite number of d-level quantum systems in the same unknown pure state σinto M systems of the same kind, in an approximation of the M-fold tensor product of the state σ.

S. G. Bindu, V. C. Kuriakose

Electromagnetic wave propagation through cold collision free plasma is studied using the nonlinear perturbation method. It is found that the equations can be reduced to the modified Kortweg-de Vries equation.

Qamar J. A. Khan, Bal Swaroop Bhatt, R. P. Jaju

Switching model with one predator and two prey species is considered. The prey species have the ability of group defence. Therefore, the predator will be attracted towards that habitat where prey are less in number. The stability analysis is carried out for two equilibrium values. The theoretical results are compared with the numerical results for a set of v

Wilhelm Fushchych

A new definition for the electromagnetic field velocity is proposed. The velocity depends on the physical fields.

Sid Deutsch

The ether can "explain" certain questionable "quantum realities" in which single, isolated photons form a diffraction pattern in a two-slit apparatus; and, similarly, single, isolated electrons form a diffraction pattern in the equivalent of a two-slit apparatus. The notion that every large object, such as the earth, carries its own ether, is

L. Alvarez-Ruso, S. K. Singh, M. J. Vicente Vacas

The reaction $νd \to μ^- Δ^{++} n$ is studied in the region of low $q^2$ to investigate the effect of deuteron structure and width of the $Δ$ resonance on the differential cross section. The results are used to extract the axial vector $N-Δ$ coupling $C^{A}_5$ from the experimental data on this reaction. The possibility to determine this coupling from electr

Tai An, Sa Ben-Hao

The idea that effective string tension increases as a result of the hard gluon kinks on a string is applied to study the strange particle production in proton-nucleus and nucleus-nucleus collisions. It is found that the effective string tension increases with the increase of centrality and mass of the colliding system as a consequence of the mini-(gluon)jet

Sa Ben-Hao, Tai An

We have used the event generator LUCIAE to analyse NA35 data of the $\bar p$ and $\barΛ$ yields, the ratio $\barΛ/\bar p$, and the transverse mass distributions of $\bar p$ and $\barΛ$ in pp and central sulphur-nucleus collisions at 200A GeV. The NA35 data could be reproduced reasonably if one assumes that the s quark pair suppression factor and concerns in

Tai An, Sa Ben-Hao

The increase of effective string tension as a result of the hard gluon kinks on a string is investigated using a parametrization form. In this form the effective string tension increasing with energies in hadron-hadron collisions is due to the mini-jet (gluon) production in the collisions. The data of the energy dependence of the strange quark suppression fa

Tai An, Sa Ben-Hao

LUCIAE is a Monte Carlo program that, connected to FRITIOF, implements both the Firecracker Model (FCM), a possible mechanism for collective multi-gluon emission from the colour fields of interacting strings, and the reinteraction of the final state hadrons in relativistic heavy ion collisions. This paper includes a brief presentation of the dynamics of LUCI

W. M. Snow, W. S. Wilburn, J. D. Bowman, M. B. Leuschner

We outline the motivation and conceptual design for a new experiment aimed at a 10-fold improvement in the accuracy of the parity-violating asymmetry A_gamma in the angular distribution of 2.2 MeV gamma rays from the n+p-->d+gamma reaction. This observable is primarily sensitive to the weak pion-nucleon coupling H_pi^1. A proof-of-principle experiment using

Kuppusamy Porsezian

Considering the coupled envelope equations in nonlinear couplers, the question of integrability is attempted. It is explicitly shown that Hirota's bilinear method is one of the simple and alternative techniques to Painlevé analysis to obtain the integrability conditions of the coupled nonlinear Schrödinger (CNLS) type equations. We also show that the cou

Ruguang Zhou

Under the Neumann constraints, each equation of the KdV hierarchy is decomposed into two finite dimensional systems, including the well-known Neumann model. Like in the case of the Bargmann constraint, the explicit Lax representations are deduced from the adjoint representation of the auxiliary spectral problem. It is shown that the Lax operator satisfies th

Baoqun Lu, Yong He, Guangjiong Ni

In this paper we give a method to obtain Darboux transformations (DTs) of integrable equations. As an example we give a DT of the dispersive water wave equation. Using the Miura map, we also obtain the DT of the Jaulent-Miodek equation. \end{abstract}

M. Senthil Velan, Muthusamy Lakshmanan

In this paper we study Lie symmetries, Kac-Moody-Virasoro algebras, similarity reductions and particular solutions of two different recently introduced (2+1)-dimensional nonlinear evolution equations, namely (i) (2+1)-dimensional breaking soliton equation and (ii) (2+1)-dimensional nonlinear Schrödinger type equation introduced by Zakharov and studied later

Riccardo Capovilla, Jemal Guven

We consider an open string described by an action of the Dirac-Nambu-Goto type with topological corrections which affect the boundary conditions but not the equations of motion. The most general addition of this kind is a sum of the Gauss-Bonnet action and the first Chern number (when the background spacetime dimension is four) of the normal bundle to the st

Riccardo Capovilla, Jemal Guven

We present a manifestly gauge covariant description of fluctuations of a relativistic extended object described by the Dirac-Nambu-Goto action with Dirac-Nambu-Goto loaded edges about a given classical solution. Whereas physical fluctuations of the bulk lie normal to its worldsheet, those on the edge possess an additional component directed into the bulk. Th

Riccardo Capovilla, Jemal Guven

We examine, from a geometrical point of view, the dynamics of a relativistic extended object with loaded edges. In the case of a Dirac-Nambu-Goto [DNG] object with DNG edges, the worldsheet $m$ generated by the parent object is, as in the case without boundary, an extremal timelike surface in spacetime. Using simple variational arguments, we demonstrate that

Mingliang Wang, Yubin Zhou, Zhibin Li

A nonlinear transformation of the dispersive long wave equations in (2+1) dimensions is derived by using the homogeneous balance method. With the aid of the transformation given here, exact solutions of the equations are obtained.

Daniel J. Arrigo, James M. Hill

Monge-Ampère equations of the form, $u_{xx}u_{yy}-u_{xy}^2=F(u,u_x,u_y)$ arise in many areas of fluid and solid mechanics. Here it is shown that in the special case $F=u_y^4f(u, u_x/u_y)$, where $f$ denotes an arbitrary function, the Monge-Ampère equation can be linearized by using a sequence of Ampère, point, Legendre and rotation transformations. This line

Noriko Arai

In this paper, the relative efficiency of two propositional systems is studied: resolution and cut-free LK in DAG. We give an upper bound for translation of resolution refutation to cut-free LK proofs. The best upper bound known was 2.

Thomas S. Salisbury, John Verzani

In this paper we present a martingale related to the exit measures of super-Brownian motion. By changing measure with this martingale in the canonical way we have a new process associated with the conditioned exit measure. This measure is shown to be identical to a measure generated by a non-homogeneous branching particle system with immigration of mass. An

Timothy Y. Chow

One of the simplest axiomatizations of a matroid is in terms of independent sets. Curiously, no such independent set axiomatization is known for Gelfand and Serganova's WP-matroids (which are ``Coxeter group analogues'' of matroids). Here we state and prove such an axiomatization in the special case of symplectic matroids. No prior knowledge of W

R. Deville, R. Gonzalo, J. A. Jaramillo

We investigate the best order of smoothness of $L^p(L^q)$. We prove in particular that there exists a $C^\infty$-smooth bump function on $L^p(L^q)$ if and only if $p$ and $q$ are both even integers and $p$ is a multiple of $q$.

S. Ferrara, A. Kehagias, H. Partouche, A. Zaffaroni

We explore the connection of anti-de-Sitter supergravity in six dimensions, based on the exceptional F(4) superalgebra, and its boundary superconformal singleton theory. The interpretation of these results in terms of a D4-D8 system and its near horizon geometry is suggested.

L. V. Belvedere, R. L. P. G. do Amaral, K. D. Rothe

We analyse the Hilbert space structure of the isomorphic gauge non-invariant and gauge invariant bosonized formulations of chiral $QCD_2$ for the particular case of the Jackiw-Rajaraman parameter $ a = 2$. The BRST subsidiary conditions are found not to provide a sufficient criterium for defining physical states in the Hilbert space and additional superselec

Kazuyuki Fujii, Tatsuo Suzuki

We give in this paper some formulas which are useful in the construction of nontrivial conserved currents for submodels of CP^1-model or QP^1-model in (1+2) dimensions. These are full generalization of our results in the previous paper (hep-th/9802105).

C. J. Burden, P. C. Tjiang

We consider the problem of designing an Ansatz for the fermion-photon vertex function, using three-dimensional quantum electrodynamics as a test case. In many existing studies, restrictions have been placed on the form of the vertex Ansatz by making the unsubstantiated assumption that in the quenched, massless limit the Landau gauge Dyson-Schwinger equations

Alan. R. White

Deep-inelastic diffractive scaling violations have provided fundamental insight into the QCD pomeron, suggesting a single gluon inner structure rather than that of a perturbative two-gluon bound state. This talk outlines a derivation of a high-energy, transverse momentum cut-off, confining solution of QCD. The pomeron, in first approximation, is a single reg

G. Karra, R. J. Rivers

In the light of recent difficulties in observing vortices in quenches of liquid $^{4}$He to its superfluid state we re-examine the Zurek scenario for their production. We find that the standard prediction is suspect because of a confusion over correlation lengths.

Juan Garcia-Bellido

One of the fundamental problems of modern cosmology is to explain the origin of all the matter and radiation in the Universe today. The inflationary model predicts that the oscillations of the scalar field at the end of inflation will convert the coherent energy density of the inflaton into a large number of particles, responsible for the present entropy of

Ramesh Anishetty

String tension is introduced in perturbative QCD without hindering ultra violet renormalizability . The running gauge coupling constant remains unaltered and the string tension in the high energy limit vanishes asymptotically. Using 1/N techinique the theory can be explicitly analytically computable with cofinement built in . Spontaneous chiral symmetry brea

H. P. Shanahan, A. C. Davis

The classical transitions between topologically distinct vacua in a SU(2)-Higgs model, using a Higgs field of mass approximately 120 GeV, is examined to probe the crossover region between the symmetric and broken phase. Assuming the Higgs mass is constant, we find the width of this crossover region is approximately 20% of the average temperature. We suggest

P. Labelle, K. Buckley

Recently, much work has been devoted to the calculation of order $α$ corrections to the decay rate of pionium, the $π^+ π^-$ bound state. In previous calculations, nonrelativistic QED corrections were neglected since they start at order $α^2$ in hydrogen and positronium. In this note, we point out that there is one correction which is actually of order $α$ t

N. Armesto

Production of Drell-Yan pairs and open and hidden heavy flavor on nuclear targets is examined within perturbative QCD. The effects of modifications of nucleon structure functions inside the nuclear medium are considered. Besides, nuclear dependence of charmonium and bottonium absorption is studied in the framework of the Glauber-Gribov model. The low energy

Sergio Caracciolo, Andrea Pelissetto

We compute the corrections to finite-size scaling for the N-vector model on the square lattice in the large-N limit. We find that corrections behave as log L/L^2. For tree-level improved hamiltonians corrections behave as 1/L^2. In general l-loop improvement is expected to reduce this behaviour to 1/(L^2 \log^l L). We show that the finite-size-scaling and th

ZEUS Collaboration

The shapes of jets with transverse energies, E_T(jet), up to 45 GeV produced in neutral- and charged-current deep inelastic e+p scattering (DIS) at Q**2 > 100 GeV**2 have been measured with the ZEUS detector at HERA. Jets are identified using a cone algorithm in the eta-phi plane with a cone radius of one unit. The jets become narrower as E_T(jet) increases.