August 1996 arXiv papers — page 14

Gerhard Buchalla

The renormalization group evolution of $ΔB=2$ transition operators is studied at leading order in heavy quark effective theory and at next-to-leading order in QCD. We calculate new contributions that were not taken into account in previous work and obtain the complete result to next-to-leading logarithmic accuracy. The various scheme and scale dependences an

Alex Pomarol

The breaking of supersymmetry is usually assumed to occur in a hidden sector. Two natural candidates for the supersymmetry breaking transmission from the hidden to the observable sector are gravity and the gauge interactions. Only the second one allows for supersymmetry breaking at low energies. I show how the two candidates deal with the flavor and the $μ$-

V. S. Fadin, R. Fiore, M. I. Kotsky

In spite of the fact that the Gribov's theorem about the region of applicability of the soft emission factorization cannot be referred literally to the case of massless charged particles, it can be used for the calculation of soft emission amplitudes in such a case also. We demonstrate this for the gluon production amplitude in the multi-Regge kinematics

Kurt Langfeld

On the level of an effective quark theory, we define confinement by the absence of quark anti-quark thresholds in correlation functions. We then propose a confining Nambu-Jona-Lasinio-type model. Its four fermion interaction in the color channel is mediated by a random color matrix. We investigate the model's phase structure as well as its behavior under

Gerhard Ecker

After a general introduction to the structure of effective field theories, the main ingredients of chiral perturbation theory are reviewed. Applications include the light quark mass ratios and pion-pion scattering to two-loop accuracy. In the pion-nucleon system, the linear sigma model is contrasted with chiral perturbation theory. The heavy-nucleon expansio

Sara Collins, Robert G. Edwards, Urs M. Heller, John Sloan

We present results of quenched $SU(3)$ hadron spectroscopy comparing $\order(a)$ improved Wilson (Clover) fermions with conventional Wilson fermions. The configurations were generated using an $\order(a^2)$ improved 6-link $SU(3)$ pure gauge action at $\beta$'s corresponding to lattice spacings of $0.15$, $0.18$, $0.20$, $0.33$, and $0.43$ fm. We find eviden

R. G. Edwards, Ivan Horvath, A. D. Kennedy

We study the non-reversibility of molecular dynamics trajectories arising from the amplification of rounding errors. We analyse the causes of such behaviour and give arguments, indicating that this does not pose a significant problem for Hybrid Monte Carlo computations. We present data for pure SU(3) gauge theory and for QCD with dynamical fermions on small

Colin Morningstar

The use of novel perturbatively-improved gluonic actions on anisotropic lattices in which the temporal spacing is much smaller than that in the spatial directions is discussed. Such actions permit more efficient measurements of noisy correlation functions, such as glueball correlators, on coarse lattices. A derivation of these actions at tree-level is outlin

Bas van den Heuvel

For SU(2) gauge theory on the three-sphere we study the dynamics of the low-energy modes. By explicitely integrating out the high-energy modes, the one-loop correction to the hamiltonian for this problem is obtained. After imposing the $θ$-dependence through boundary conditions in configuration space, we obtain the glueball spectrum of the effective theory w

M. Goeckeler, R. Horsley, E. -M. Ilgenfritz, H. Oelrich

About half the mass of a hadron is given from gluonic contributions. In this talk we calculate the chromo-electric and chromo-magnetic components of the nucleon mass. These computations are numerically difficult due to gluon field ultra-violet fluctuations. Nevertheless a high statistics feasibility run using quenched Wilson fermions seems to show reasonable

Petrus Pennanen

A continuum extrapolation of static four- and two-quark energies calculated in quenched SU(2) is done based on Sommer's method of setting the scale. A model for four-quark energies with explicit gluonic degrees of freedom removed is fitted to these energies and the behavior of the parameters of the model is investigated.

Margarita Garcia Perez, Jeroen Snippe, Pierre van Baal

We introduce a new Symanzik improved action by adding a 2x2 plaquette in such a way that the Feynman rules in the covariant gauge simplify. We call this the square Symanzik action. Some comparisons with the continuum and the standard Wilson action are made in intermediate volumes, where mass ratios are accurately known and the precise amount of improvement c

G. Di Cecio, A. Di Giacomo, G. Paffuti, M. Trigiante

A disorder parameter is constructed which signals the condensation of vortices. The construction is tested by numerical simulations on lattice.

Clifford M. Will, Alan G. Wiseman

We derive the gravitational waveform and gravitational-wave energy flux generated by a binary star system of compact objects (neutron stars or black holes), accurate through second post-Newtonian order ($O[(v/c)^4] \sim O[(Gm/rc^2)^2]$) beyond the lowest-order quadrupole approximation. We cast the Einstein equations into the form of a flat-spacetime wave equ

Karel V. Kuchar, Joseph D. Romano, Madhavan Varadarajan

We present an anomaly-free Dirac constraint quantization of the string-inspired dilatonic gravity (the CGHS model) in an open 2-dimensional spacetime. We show that the quantum theory has the same degrees of freedom as the classical theory; namely, all the modes of the scalar field on an auxiliary flat background, supplemented by a single additional variable

Dieter R. Brill

The (single) black hole solutions of Bañados, Teitelboim and Zanelli (BTZ) in 2+1 dimensional anti-de Sitter space are generalized to an arbitrary number $n$ of such black holes. The resulting multi-black-hole (MBH) spacetime is locally isometric to anti-de Sitter space, and globally it is obtained from the latter as a quotient space by means of suitable ide

J. K. Freericks, E. J. Nicol, A. Y. Liu, A. A. Quong

The McMillan-Rowell tunneling inversion program, which extracts the electron-phonon spectral function $α^2F(Ω)$ and the Coulomb pseudopotential $μ^*$ from experimental tunneling data, is generalized to include the lowest-order vertex correction. We neglect the momentum dependence of the electron-phonon matrix elements, which is equivalent to using a local ap

K. Ziegler

A grand canonical ensemble of interacting bosons is considered. The zero temperature phase diagram is evaluated from the mean-field approximation of the functional integral. Three phases are found: a superfluid, a normal fluid and a Mott insulator.

A. G. Green, I. I. Kogan, A. M. Tsvelik

Using a self consistent approximation for the spin distribution of Skyrmions in the quantum Hall effect, we obtain an effective action for the Skyrmion coordinates. The energy functional is minimised for a periodic distribution of Skyrmions with an underlying hexagonal symetry. We calculate the phonon spectrum of this lattice and find that near the classical

C. A. Piguet, D. F. Wang, C. Gruber

In this work, we study a continuous quantum system of a mixture of bosons and fermions with the supersymmetry SU(m|n). The particles are confined in a harmonic well and interact with each other through the 1/r2 interaction. The ground state wavefunction is constructed explicitly for the most general SU(m|n) case, with the ground state energy given explicitly

M. P. Nightingale, C. J. Umrigar

This review covers applications of quantum Monte Carlo methods to quantum mechanical problems in the study of electronic and atomic structure, as well as applications to statistical mechanical problems both of static and dynamic nature. The common thread in all these applications is optimization of many-parameter trial states, which is done by minimization o

Alessandro Torcini, Helge Frauenkron, Peter Grassberger

The phase-turbulent (PT) regime for the one dimensional complex Ginzburg-Landau equation (CGLE) is carefully studied, in the limit of large systems and long integration times, using an efficient new integration scheme. Particular attention is paid to solutions with a non-zero phase gradient. For fixed control parameters, solutions with conserved average phas

Christopher W. Mauche

Data obtained by the Extreme Ultraviolet Explorer satellite are used to determine the EUV spectrum of the quasi-coherent oscillations of the dwarf nova SS Cygni. It is found that the spectrum of the oscillations is neither blue nor red nor grey relative to the net (oscillation-phase integrated) spectrum, and hence that the oscillations cannot be explained by

David I. Kaiser

Preheating following the inflationary phase in models of open inflation is considered. The most significant difference from a preheating scenario in flat space is that supercurvature modes can be populated and amplified in the open universe. In certain models, such modes can dominate the usual resonant particle production, thus altering the ensuing thermal h

B. J. Wilkes, P. J. Green, S. Mathur, J. C. McDowell

Many years of study have failed to conclusively establish relations between a quasar's spectral energy distribution (SED) and the emission lines it is thought to produce. This is at least partially due to the lack of well-observed SEDs. We present initial results from a line--SED study for a sample of 43 quasars and active galaxies for which we have opti

D. L. Jones, R. A. Preston, D. W. Murphy, D. L. Jauncey

The remarkably strong radio gravitational lens PKS 1830-211 consists of a one arcsecond diameter Einstein ring with two bright compact (milliarcsecond) components located on opposite sides of the ring. We have obtained 22 GHz VLBA data on this source to determine the intrinsic angular sizes of the compact components. Previous VLBI observations at lower frequ

Matthew Webster, Ofer Lahav, Karl Fisher

We utilise the method of Wiener reconstruction with spherical harmonics and Bessel functions to recover the density and velocity fields from the IRAS 1.2Jy redshift survey. The results are robust to changes in prior parameters and the number of expansion coefficients. Maps of these fields are presented in a variety of projections. Many known structures are o

A. Sornborger, R. Brandenberger, B. Fryxell, K. Olson

The clustering of baryons and cold dark matter induced by a single moving string is analyzed numerically making use of a new three-dimensional Eulerian cosmological hydro code$^{1)}$ which is based on the PPM method to track the baryons and the PIC method to evolve the dark matter particles. A long straight string moving with a speed comparable to $c$ induce

A. Sornborger, B. Fryxell, K. Olson, P. MacNeice

We present a method for integrating the cosmological hydrodynamical equations including a collisionless dark matter component. For modelling the baryonic matter component, we use the Piecewise Parabolic Method (PPM) which is a high-accuracy shock capturing technique. The dark matter component is modeled using gravitationally interacting particles whose evolu

Yuri G Prokhorov

Let $f:X\to S$ be an extremal contraction from a threefolds with terminal singularities onto a surface (so called Mori conic bundle). We study some particular cases of such contractions: quotients of usual conic bundles and index two contractions. Assuming Reid's general elephants conjecture we also obtain a rough classification. We present many examples

P. Furlan, A. Ch. Ganchev, V. B. Petkova

We reconsider the earlier found solutions of the Knizhnik-Zamolodchikov (KZ) equations describing correlators based on the admissible representations of $A_1^{(1)}$. Exploiting a symmetry of the KZ equations we show that the original infinite sums representing the 4-point chiral correlators can be effectively summed up. Using these simplified expressions wit

Joseph Lipman, Pramathanath Sastry

We construct a canonical pseudofunctor ^# on the category of finite-type maps of (say) connected noetherian universally catenary finite-dimensional separated schemes, taking values in the category of Cousin complexes. This pseudofunctor is a concrete approximation to the restriction of the Grothendieck Duality pseudofunctor ^! to the full subcategory of the

B. Enriquez, V. Rubtsov

We construct quasi-Hopf algebras quantizing double extensions of the Manin pairs of Drinfeld, associated to a curve with a meromorphic differential, and the Lie algebra sl(2). This construction makes use of an analysis of the vertex relations for the quantum groups obtained in our earlier work, PBW-type results and computation of $R$-matrices for them; its k

G. Oshanin, J. De Coninck, A. Blumen, S. F. Burlatsky

We study the direct incoherent energy transfer from an immobile excited donor molecule to acceptor molecules, which are all attached to polymer chains, randomly arranged in a viscous solvent. The decay forms are found explicitly, in terms of an optimal-fluctuation method, for arbitrary conformations of polymers.

A. Balysh, A. De Silva, V. I. Lebedev, K. Lou

$^{48}$Ca, the lightest double beta decay candidate, is the only one simple enough to be treated exactly in the nuclear shell model. Thus, the $ββ(2ν)$ half-life measurement, reported here, provides a unique test of the nuclear physics involved in the $ββ$ matrix element calculation. Enriched $^{48}$Ca sources of two different thicknesses have been exposed i

D. G. Polyakov

Recent work on the temperature-driven delocalization in the quantum Hall regime is reviewed, with emphasis on the role of electron-electron interactions and the correlation properties of disorder. We have stressed (i) the crucial role of the Coulomb interaction in the integer quantum Hall effect; (ii) the classical aspects of electron dynamics in samples wit

V. I. Yudson

It has been shown that the presence of a metal plate near a double quantum well with spatially separated electron and hole layers may lead to a drastic reconstruction of the system state with the formation of stable charged complexes of several electrons bound to a spatially separated hole. Complexes of both the Fermi and the Bose statistics may coexist in t

Elizabeth. A. Praton, Adrian L. Melott, Margaret Q. McKee

We investigate a distortion in redshift-space which causes galaxies to appear to lie in walls concentric about the observer, forming a rough bull's-eye pattern. We simulate what an observer would see in a thin slice of redshift-space, including a magnitude limit and constant slice angle. The result is an enhanced ring of galaxies encircling the observer at a

D. Ebert, T. Feldmann, H. Reinhardt

We consider the NJL model as an effective quark theory to describe the interaction which is responsible for the quark flavor dynamics at intermediate energies. In addition to the usual ultraviolet cut-off which is necessary since the model is non-renormalizable, we also introduce an infrared cut-off which drops off the unknown confinement part of the quark i

Ping Xu

We study various aspects of Fedosov star-products on symplectic manifolds. By introducing the notion of "quantum exponential maps", we give a criterion characterizing Fedosov connections. As a consequence, a geometric realization is obtained for the equivalence between an arbitrary *-product and a Fedosov one. Every Fedosov *-product is shown to be a

David Tsiklauri

A phenomenon analogous to the conical refraction well-known in the crystalooptics and crystaloacoustics is considered for the magnetohydrodynamical waves in a collisionless plasma with anisotropic thermal pressure. Imposing the most general (generalization of Tsiklauri, 1996, Phys. Plasmas, 3, 800) condition for the existence of the phenomenon, angle of the

Emil Martinec

N=(2,1) heterotic string theory provides clues about hidden structure in M-theory related to string duality; in effect it geometrizes some aspects of duality. The program whereby one may deduce this hidden structure is outlined, together with the results obtained to date. Speculations are made as to the eventual shape of the theory. Talk presented at Strings

Tadeusz Wibig

In that paper we discuss possibilities of using the Artificial Neural Network technic for the individual Extensive Air Showers data evaluation. It is shown that the recently developed new computational methods can be used in studies of EAS registered by very large and complex detector systems. The ANN can be used to classify showers due to e.g. primary parti

K. Choi, E. J. Chun, J. E. Kim

We study cosmological implications of supersymmetric axion models in which the axion scale is generated radiatively. Such models lead to the so-called thermal inflation and subsequent reheating should be constrained not to yield a too large axion energy density at the time of nucleosynthesis. We examine how plausible it is that this nucleosynthesis constrain

T. Reisz

Linked cluster expansions provide a useful tool both for analytical and numerical investigations of lattice field theories. The expansion parameter is the interaction strength fields at neighboured lattice sites are coupled. They result into convergent series for free energies, correlation functions and susceptibilities. The expansions have been generalized

R. C. Brower, K. N. Orginos, C-I Tan

We investigate the Maximally Abelian (MA) Projection for a single $SU(2)$ instanton in continuum gauge theory. We find that there is a class of solutions to the differential MA gauge condition with circular monopole loops of radius $R$ centered on the instanton of width $ρ$. However, the MA gauge fixing functional $G$ decreases monotonically as $R/ρ\rightarr

Stephen C. Creagh, Niall D. Whelan

We derive a trace formula for the splitting-weighted density of states suitable for chaotic potentials with isolated symmetric wells. This formula is based on complex orbits which tunnel through classically forbidden barriers. The theory is applicable whenever the tunnelling is dominated by isolated orbits, a situation which applies to chaotic systems but al

D. R. Patton, C. J. Pritchet, H. K. C. Yee, E. Ellingson

A redshift sample of 545 field galaxies is used to examine how the galaxy merger rate changes with redshift, and how mergers affect the observed properties of galaxies in close pairs. Close pairs are defined as those with projected separations less than 20 h^{-1} kpc. At a mean redshift of 0.33, it is found that 7.1 +/- 1.4 % of galaxies are in close physica

P. Molaro, P. Bonifacio, F. Castelli, L. Pasquini

We present observations of the Be II 313.0 nm resonance doublet in 14 halo and old disk stars with metallicities ranging from [Fe/H]=-0.4 to about -3.0 obtained with the CASPEC spectrograph of the ESO 3.6m telescope at a FWHM about 8.6 km/s resolution. Abundances are derived by means of the synthetic spectra technique employing Kurucz (1993) atmospheric mode

Mark Gross, P. M. H. Wilson

We give an example of the recent proposed mirror construction of Strominger, Yau and Zaslow in ``Mirror Symmetry is T-duality,'' hep-th/9606040. The paper first considers mirror symmetry for K3 surfaces in light of this construction. We then consider the example of mirror symmetry for Calabi-Yau threefolds of the type considered by Voisin and Borcea,

L. Andrianopoli, R. D'Auria, S. Ferrara

We generalize central-charge relations and differential identities of N=2 Special Geometry to N extended supergravity in any dimension 4 \leq D <10, and p-extended objects. We study the extremization of the ADM mass per unit of p-volume of BPS extended objects. Runaway solutions for a ``dilaton&#39;&#39; degree of freedom leading to a vanishing result are in

R. W. Gebert, H. Nicolai

An affine vertex operator construction at arbitrary level is presented which is based on a completely compactified chiral bosonic string whose momentum lattice is taken to be the (Minkowskian) affine weight lattice. This construction is manifestly physical in the sense of string theory, i.e., the vertex operators are functions of DDF ``oscillators&#39;&#39;

I. Antoniadis, C. Bachas, C. Fabre, H. Partouche

We discuss the equivalence between Type I, Type II and Heterotic N=2 superstring theories in four dimensions. We study the effective field theory of Type I models obtained by orientifold reductions of Type IIB compactifications on $K_3\times T^2$. We show that the perturbative prepotential is determined by the one-loop corrections to the Planck mass and is a

H. B. Kim, C. Munoz

We perform an analysis of the soft supersymmetry-breaking terms arising in Calabi-Yau compactifications. The sigma-model contribution and the instanton correction to the Kähler potential are included in the computation. The existence of off-diagonal moduli and matter metrics gives rise to specific features as the possibility of having scalars heavier than ga

M. Cacciari, M. Greco, S. Rolli, A. Tanzini

Fragmentation functions for heavy-light mesons, like the charmed D, D^* mesons, are proposed. They rest on next-to-leading QCD Perturbative Fragmentation Functions for heavy quarks, with the addition of a non-perturbative term describing phenomenologically the quark --> meson transition. The cross section for production of large p_T D, D^* mesons at the Teva

Yoshitaka Okumura

Within one loop approximation, the renormalization group analysis of the Higgs boson mass is performed with an initial condition induced by $m_{_H}=\sqrt{2}m_{_W}$ which is presented in the new scheme of our noncommutative differential geometry for the reconstruction of the standard model. This initial condition holds at energy derived from $g^2=(5/3)g&#39;^

A. S. Cârstea

The Hirota bilinear formalism and soliton solutions for a generalized Volterra system is presented. Also, starting from the soliton solutions, we obtain a class of nonsingular rational solutions using the &#34;long wave&#34; limit procedure of Ablowitz and Satsuma, and appropriate &#34;gauge&#34; transformations. Their properties are also discussed and it is

Kimball A. Milton

The insufficiency of the energy radiated in the model of Eberlein is discussed.

V. P. Karassiov, V. L. Derbov, S. I. Vinitsky, Olga M. Priyutova

Polarization coherent states (PCS) are considered as generalized coherent states of $SU(2)_p$ group of the polarization invariance of the light fields. The geometric phases of PCS are introduced in a way, analogous to that used in the classical polarization optics.

S. Loesch, Y-K Zhou, J-B Zuber

New identities on traces of representations of the Hecke algebra on the spaces of paths on graphs are presented. These identities are relevant in the computation of partition functions with fixed boundary conditions and of two-point correlation functions in a class of lattice models. They might also help to determine the Boltzmann weights of these (allegedly

Wenbin Zhang, Jorge Vinals

We present a theoretical study of nonlinear pattern formation in parametric surface waves for fluids of low viscosity, and in the limit of large aspect ratio. The analysis is based on a quasi-potential approximation to the equations governing fluid motion, followed by a multiscale asymptotic expansion in the distance away from threshold. Close to onset, the

G. A. Lalazissis, M. M. Sharma, P. Ring, Y. K. Gambhir

We have carried out a study of superheavy nuclei in the framework of the Relativistic Mean-Field theory. Relativistic Hartree-Bogoliubov (RHB) calculations have been performed for nuclei with large proton and neutron numbers. A finite-range pairing force of Gogny type has been used in the RHB calculations. The ground-state properties of very heavy nuclei wit

A. Gil, J. A. Gomez Tejedor, E. Oset

In this paper we calculate the cross section for Virtual Compton Scattering off nuclei in the delta resonance region. We also calculate the background for the process from Coherent Bremsstrahlung in nuclei and explore the regions where the Virtual Compton Scattering cross section dominates. The study also shows that it is possible to extract the cross sectio

Bernd Kohler, Paolo Ruggerone, Matthias Scheffler

Helium atom scattering (HAS) studies of the H-covered Mo(110) and W(110) surfaces reveal a twofold anomaly in the respective dispersion curves. In order to explain this unusual behavior we performed density functional theory calculations of the atomic and electronic structure, the vibrational properties, and the spectrum of electron-hole excitations of those

F. Ghaboussi

We discuss a general quantum theoretical example of quantum cohomology and show that various mathematical aspects of quantum cohomology have quantum mechanical and also observable significance.

G. E. Arutyunov, S. A. Frolov, P. B. Medvedev

It is shown that the elliptic Ruijsenaars-Schneider model can be obtained from the cotangent bundle over the two-dimensional current group by means of the Hamiltonian reduction procedure.

Howard Baer, Chih-hao Chen, Xerxes Tata

If $R$-parity is not conserved, the lightest supersymmetric particle (LSP) could decay via lepton number violating or baryon number violating interactions. The latter case is particularly insidious since it leads to a reduction of the $\eslt$ as well as leptonic signals for supersymmetry. We evaluate cross sections for jets plus $\eslt$, 1$\ell$, $2\ell$ (sa

Aida X. El-Khadra

The status of determinations of the strong coupling constant based on lattice QCD is reviewed.

Y. J. Feng, C. S. Lam

A graphical method is developed to study the total or partial cancellation of gauge-dependent (divergence) terms in electroweak theory. The method is used to work out rules in the Gervais-Neveu gauge, whose triple-gauge vertex contains three terms rather than the usual six. This and other features of the gauge lead to an enormous saving of algebraic labor in

A. Ilakovac

The evaluation, systematic analysis and numerical study of the semileptonic $τ$-lepton decays with two mesons in the final state has been made in the frame of the standard model extended by right handed neutrinos. In the analysis, heavy-neutrino nondecoupling effects, finite quark masses, quark and meson mixings, finite widths of vector mesons, chiral symmet

L. Dick, V. Karapetian, R. Barni, G. Preparata

In the framework of Anisotropic Chromo Dynamics, a non-perturbative model of QCD based on magnetic condensation in the vacuum, we develope a picture of the Pomeron. Within this model we are able to calculate the diffractive contribution to deep inelastic scattering in the small Bjorken x region, actually probed at Hera. We calculate the diffractive structure

Michael Creutz

I discuss the mass parameters appearing in the gauge theory of the strong interactions, concentrating on the two flavor case. I show how the effect of the CP violating parameter $θ$ is simply interpreted in terms of the state of the æther via an effective potential for meson fields. For degenerate flavors I show that a first order phase transition is expecte

Kimmo Kainulainen

A computation of nucleosynthesis bounds on the masses of long-lived Dirac and Majorana neutrinos is reviewed. In particular an explicit treatment of the ``differential heating&#39;&#39; of the $\nue$ and $\bnue$ ensembles due to the residual out-of-equilibrium annihilations of decoupled heavy neutrinos is included. The effect is found to be considerably weak

Liu Lianshou, Hu Yuan, Deng Yue

It is argued that the experimentally observed strong upward-bending of the logarithm of factorial moments versus that of phase space partition number in the higher-dimensional phase space of nucleus-nucleus collisions is due to the superposition of elementary collision processes in these collisions. A direct implication of this observation is that, at high e

Matthias Neubert

We present a QCD sum-rule determination of the heavy-quark kinetic energy inside a heavy meson, $-λ_1/2 m_Q$, which is consistent with the field-theory analog of the virial theorem. We obtain $-λ_1\approx (0.10\pm 0.05)~\mbox{GeV}^2$, significantly smaller than a previous sum-rule result, but in good agreement with recent determinations from the analysis of

Liu Lianshou, Zhang Yang, Deng Yue

The experimental results on the falling down of scaled factorial moments in azimuthal variable $ϕ$ is studied in some detail. It is shown that this phenomenon may be referred to the influence of transverse momentum conservation. The existing experimental data from DELPHI, EMU08, NA22 and UA1 are successfully explained. Various methods are proposed to partly

Utpal Sarkar, Rathin Adhikari

We consider generation of baryon asymmetry of the universe through $R-$parity violation in a scenario in which out-of-equilibrium condition is satisfied by making the electroweak phase transition to be first order. We study all the $R-$parity violating interaction which can generate $(B-L)$ asymmetry which then converts to baryon asymmetry of the universe. W

Geoffrey T. Bodwin

We present a method for implementing gauge theories of chiral fermions on the lattice.

H. Meyer-Ortmanns, T. Reisz

Linked cluster expansions are generalized from an infinite to a finite volume on a $d$-dimensional hypercubic lattice. They are performed to 20th order in the expansion parameter to investigate the phase structure of scalar $O(N)$ models for the cases of $N=1$ and $N=4$ in 3 dimensions. In particular we propose a new criterion to distinguish first from secon

Martin Zach, Manfried Faber, Peter Skala

In any Abelian gauge theory with an action periodic in the link variables one can perform a duality transformation not only in the partition function, but also in correlation functions including Polyakov loops. The calculation of expectation values in the confinement phase, like electric field strength or monopole currents in the presence of external charges

Adriano Di Giacomo, Enrico Meggiolaro, Haralambos Panagopoulos

We study, by numerical simulations on a lattice, the behaviour of the gauge--invariant field strength correlators in QCD both at zero temperature, down to a distance of 0.1 fm, and at finite temperature, across the deconfinement phase transition.

Michael Creutz, Michel Tytgat

Coupling gauge fields to the chiral currents from an effective Lagrangian for pseudoscalar mesons naturally gives rise to a species doubling phenomenon similar to that seen with fermionic fields in lattice gauge theory.

M. Karjalainen, M. Laine, J. Peisa

We study the order of the phase transition in the 3d U(1)+Higgs theory, which is the Ginzburg-Landau theory of superconductivity. We confirm that for small scalar self-coupling the transition is of first order. For large scalar self-coupling the transition ceases to be of first order, and a non-vanishing scalar mass suggests that the transition may even be o

C. Campagnari, M. Franklin

Evidence for pair production of a new particle consistent with the Standard Model top quark has been reported recently by groups studying proton anti-proton collisions at 1.8 TeV center of mass energy at the Fermi National Accelerator Laboratory. In this paper we review the history of the search for the top quark in electron positron and proton anti-proton c

Sandra Leone

We report preliminary results from the analyses looking for top candidates in the channel with 6 jets in the final state (all hadronic) and in the dilepton channel with one tau lepton (tau dilepton), using a data sample of 110 pb^{-1} collected by the CDF experiment at the Fermilab Tevatron Collider.

Raphael Bousso, Stephen W. Hawking

In the inflationary era, black holes came into existence together with the universe through the quantum process of pair creation. We calculate the pair creation rate from the no boundary proposal for the wave function of the universe. Our results are physically sensible and fit in with other descriptions of pair creation. The tunnelling proposal, on the othe

Raphael Bousso, Stephen W. Hawking

We summarise recent work on the quantum production of black holes in the inflationary era. We describe, in simple terms, the Euclidean approach used, and the results obtained both for the pair creation rate and for the evolution of the black holes.

Massimo Galluccio, Marco Litterio, Franco Occhionero

We propose to uncover the signature of a stringy era in the primordial Universe by searching for a prominent peak in the relic graviton spectrum. This feature, which in our specific model terminates an $ω^3$ increase and initiates an $ω^{-7}$ decrease, is induced during the so far overlooked bounce of the scale factor between the collapsing deflationary era

T. Kloesch, P. Schaller, T. Strobl

We present a classification of all global solutions (with Lorentzian signature) for any general 2D dilaton gravity model. For generic choices of potential-like terms in the Lagrangian one obtains maximally extended solutions on arbitrary non-compact two-manifolds, including various black-hole and kink configurations. We determine all physical quantum states

Michael J. Pfenning, L. H. Ford

Quantum inequality restrictions on the stress-energy tensor for negative energy are developed for three and four-dimensional static spacetimes. We derive a general inequality in terms of a sum of mode functions which constrains the magnitude and duration of negative energy seen by an observer at rest in a static spacetime. This inequality is evaluated explic

Anderson Ilha, Jose&#39; P. S. Lemos

The extension of the general relativity theory to higher dimensions, so that the field equations for the metric remain of second order, is done through the Lovelock action. This action can also be interpreted as the dimensionally continued Euler characteristics of lower dimensions. The theory has many constant coefficients apparently without any physical mea

S. P. Strong, David G. Clarke

The cuprate superconductors and certain organic conductors exhibit transport which is qualitatively anisotropic, yet at the same time other properties of these materials strongly suggest the existence of a Fermi surface and low energy excitations with substantial free electron character. The former of these features is very difficult to account for if the ma

Leon Balents, M. Cristina Marchetti, Leo Radzihovsky

We consider a periodic lattice rapidly driven through a quenched random potential as a model of a moving Abrikosov lattice. In addition to the transverse phonon displacements $u_y$, we consider the displacements $u_x$ along the direction of motion, which were assumed to be small in earlier treatments. We show that these displacements are in fact divergent ev

Stefan Scheidl, Valerii Vinokur

We study the dynamic response of driven systems in the presence of quenched disorder. A simple heuristic model for hysteretic creep of elastic manifolds is proposed and evaluated numerically. It provides a qualitative explanation of the phenomenology observed in experiments on high-temperature superconductors.

F. Ghaboussi

It is shown that an observed length in the potential drops across IQHE samples is a universal length for a given value of magnetic field which results from the quantum mechanical uncertainty relation.

Thierry Giamarchi, Hélène Maurey

We examine the effects of disorder in one-dimensional systems. We link the case of a few impurities, typical of a short quantum wire, to that of a finite density of scatterers more appropriate for a long wire or a macroscopic system. Finally we investigate the effects of long-range interactions on the transport in 1D systems. We predict in that case a conduc

N. Kumar, Nivedita Deo

The density-of-states (DOS) for a magnetized (B) two-dimensional electron gas (2DEG) containing point scatterers of arbitrary strengths, concentration ($n_s$) and distribution is analyzed. It is shown from the first principles that for \(n_s \leq B/Φ_o \equiv n_B\), the areal density of flux quanta \(Φ_o \equiv hc/e\), the DOS retains the extensive degenerac

Nigel Collier

This paper look at how the Hopfield neural network can be used to store and recall patterns constructed from natural language sentences. As a pattern recognition and storage tool, the Hopfield neural network has received much attention. This attention however has been mainly in the field of statistical physics due to the model&#39;s simple abstraction of spi

Wouter-Jan Rappel, Alain Karma

We investigate numerically the dynamics of large networks of $N$ globally pulse-coupled integrate and fire neurons in a noise-induced synchronized state. The powerspectrum of an individual element within the network is shown to exhibit in the thermodynamic limit ($N\to \infty$) a broadband peak and an additional delta-function peak that is absent from the po

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

We report high spatial resolution HST imagery and photometry of three well-studied, intense galactic X-ray binaries, X2129+47, CAL 87 and GX17+2. All three sources exhibit important anomalies, not readily interpreted by conventional models. Each source also lies in a severely crowded field, and in all cases the anomalies would be removed if much of the light