May 1998 arXiv papers — page 18

Hai-Yang Cheng, Kwei-Chou Yang

The B meson lifetime ratios are calculated to the order of $1/m_b^3$ in the heavy quark expansion. The predictions of those ratios are dependent on four unknown hadronic parameters $B_1$, $B_2$, $ε_1$ and $ε_2$, where $B_1$ and $B_2$ parametrize the matrix elements of color singlet-singlet four-quark operators and $ε_1$ and $ε_2$ the matrix elements of color

J. Gegelia

The equivalence of subtractively renormalized and cut-off effective field theories is demonstrated for the example of very low energy effective field theory for the nucleon-nucleon interaction.

Ashoke Sen

S-duality symmetry of type IIB string theory predicts the existence of a stable non-BPS state on an orbifold five plane of the type IIB theory if the orbifold group is generated by the simultaneous action of (-1)^{F_L} and the reversal of sign of the four coordinates transverse to the orbifold plane. We calculate the mass of this state by starting from a pai

Reggie Brown

We present methods for approximating the mapping that defines the invariant manifold for two systems exhibiting generalized synchronization. If the equations of motion are known then an analytic approximation to the mapping can be found. If time series data is used then a numerical approximation can be found.

B. Krippa, J. T. Londergan

The processes involving low energy $\bar{K}N$ and $Yπ$ interactions (where $Y= Σ$ or $Λ$) are studied in the framework of heavy baryon chiral perturbation theory with the $Λ$(1405) resonance appearing as an independent field. The leading and next-to-leading terms in the chiral expansion are taken into account. We show that an approach which explicitly includ

S. C. Phatak

The renormalised form factors for pseudoscalar meson-baryon coupling are computed in chiral colour dielectric model. This has been done by rearranging the Lippmann-Schwinger series for the meson baryon scattering matrix so that it can be expressed as a baryon pole term with renormalized form factors and baryon masses and the rest of the terms which arise fro

Alexander Krasulin

In this series of papers I examine a special kind of geometric objects that can be defined in space-time --- five-dimensional tangent vectors. Similar objects exist in any other differentiable manifold, and their dimension is one unit greater than that of the manifold. Like ordinary tangent vectors, the considered five-dimensional vectors and the tensors con

Arthur G. Sergheyev

We present a simple way of generating the infinite set of Jacobi tensors, compatible with a given one, via the "gauge transformations" of the functions on Jacobi manifold. We consider also some applications of this result to the construction of bi-Hamiltonian systems on Jacobi manifolds.

Jens Bolte, Stefan Johansson

Let O^1 be a (cocompact) Fuchsian group, given as the group of units of norm one in a maximal order O in an indefinite quaternion division algebra over Q. Using the (classical) Selberg trace formula, we show that the eigenvalues of the automorphic Laplacian for O^1 and their multiplicities coincide with the eigenvalues and multiplicities of the Laplacian def

Suemi Rodriguez-Romo

We present all inner actions on the Clifford algebra C(1,3) of the quantum group GL_2 constructed by Dipper and Donkin.

A. R. Gover, J. Slovak

New universal invariant operators are introduced in a class of geometries which include the quaternionic structures and their generalisations as well as 4-dimensional conformal (spin) geometries. It is shown that, in a broad sense, all invariants and invariant operators arise from these universal operators and that they may be used to reduce all invariants p

H. Montani, R. Montemayor

We develop a Lagrangian approach for constructing a symplectic structure for singular systems. It gives a simple and unified framework for understanding the origin of the pathologies that appear in the Dirac-Bergmann formalism, and offers a more general approach for a symplectic formalism, even when there is no Hamiltonian in a canonical sense. We can thus o

J. Bockenhauer, D. E. Evans

We apply the theory of $α$-induction of sectors which we elaborated in our previous paper to several nets of subfactors arising from conformal field theory. The main application are conformal embeddings and orbifold inclusions of SU(n) WZW models. For the latter, we construct the extended net of factors by hand. Developing further some ideas of F. Xu, our tr

Andreas Aste, G"unter Scharf, Urs Walther

The importance of a rigorous definition of the singular degree of a distribution is demonstrated on the case of two-dimensional QED (Schwinger model). Correct mathematical treatment of second order vacuum polarization in the perturbative approach is crucial in order to obtain the Schwinger mass of the photon by resummation.

S. L. Lyakhovich, A. A. Sharapov, K. M. Shekhter

The Kirillov-Souriau-Kostant construction is applied to derive the classical and quantum mechanics for the massive spinning particle in arbitrary dimension.

A. S. Belyaev, O. J. P. Eboli, M. C. Gonzalez-Garcia, J. K. Mizukoshi

We analyze the potential of the CERN Large Hadron Collider to study anomalous quartic vector--boson interactions through the production of vector--boson pairs accompanied by jets. In the framework of $SU(2)_L \otimes U(1)_Y$ chiral Lagrangians, we examine all effective operators of order $p^4$ that lead to new four--gauge--boson interactions but do not alter

K. Golec-Biernat, J. Kwiecinski, A. D. Martin

Diffractive dijet photoproduction is proposed as a probe of the off-diagonal gluon distribution and its evolution. Predictions for the transverse momentum distribution of the jets are given. Differences with DGLAP evolution are highlighted.

K. Fialkowski, R. Wit

Various methods of implementing the Bose-Einstein effect into Monte Carlo generators, especially for the process e^+ e^- > W^+ W^-, are briefly reviewed and their predictions for the W mass shifts are compared. The weight methods, which yield very similar predictions independent on the detailed prescription for weights, are discussed in more detail. In parti

G. Domokos, S. Kovesi-Domokos

Orbiting detectors will be able to observe showers initiated by neutrinos penetrating the Earth and interacting close to their exit point. There is a correlation between the impact parameter of the incident neutrino and its energy. We study the development of upward going, neutrino induced showers in the atmosphere.

P. Cea, M. Consoli, L. Cosmai

General arguments related to ``triviality&#39;&#39; predict that, in the broken phase of $(λΦ^4)_4$ theory, the condensate $<Φ>$ re-scales by a factor $Z_ϕ$ different from the conventional wavefunction-renormalization factor, $Z_{prop}$. Using a lattice simulation in the Ising limit we measure $Z_ϕ=m^2 χ$ from the physical mass and susceptibility and $Z_{pro

Claus Lämmerzahl

The role of the equivalence principle in the context of non-relativistic quantum mechanics and matter wave interferometry, especially atom beam interferometry, will be discussed. A generalised form of the weak equivalence principle which is capable of covering quantum phenomena too, will be proposed. It is shown that this generalised equivalence principle is

Patrick R Brady, Serge Droz, Sharon M Morsink

It was long believed that the singularity inside a realistic, rotating black hole must be spacelike. However, studies of the internal geometry of black holes indicate a more complicated structure is typical. While it seems likely that an observer falling into a black hole with the collapsing star encounters a crushing spacelike singularity, an observer falli

D. K. Klimov, D. Thirumalai

We investigate the sequence-dependent properties of proteins that determine the dual requirements of stability of the native state and its kinetic accessibility using simple cubic lattice models. Three interaction schemes are used to describe the potentials between residues. We show that, under the simulation conditions when the native basin of attraction (N

E. M. Chudnovsky, D. A. Garanin

We have found a novel feature of the bistable large-spin model described by the Hamiltonian H = -DS_z^2 - H_xS_x.The crossover from thermal to quantum regime for the escape rate can be either first (H_x<SD/2) or second (SD/2<H_x<2SD) order, that is, sharp or smooth, depending on the strength of the transverse field. This prediction can be tested experimental

E. A. Jagla

The pressure-temperature phase diagram of a one-component system, with particles interacting through a spherically symmetric pair potential in two dimensions is studied. The interaction consists of a hard core plus an additional repulsion at low energies. It is shown that at zero temperature, instead of the expected isostructural transition due to core colla

D. A. Garanin, E. M. Chudnovsky

The dynamical theory of thermally activated resonant magnetization tunneling in uniaxially anisotropic magnetic molecules such as Mn_12Ac (S=10) is developed.The observed slow dynamics of the system is described by master equations for the populations of spin levels.The latter are obtained by the adiabatic elimination of fast degrees of freedom from the dens

D. A. Garanin

The integral relaxation time describing the thermoactivated escape of a uniaxial quantum spin system interacting with a boson bath is calculated analytically in the whole temperature range. For temperatures T much less than the barrier height ΔU, the level quantization near the top of the barrier and the strong frequency dependence of the one-boson transitio

A. N. Korotkov, K. K. Likharev

We analyze the operation of the wireless single-electron logic family based on single-electron-parametron cells. Parameter margins, energy dissipation, and the error probability are calculated using the orthodox theory of single-electron tunneling. Circuits of this family enable quasi-reversible computation with energy dissipation per bit much lower than the

G. Oshanin, J. De Coninck, A. M. Cazabat, M. Moreau

We study the behavior of a semi-infinite monolayer, which is placed initially on a half of an infinite in both directions, ideal crystalline surface, and then evolves in time due to random motion of the monolayer particles. Particles dynamics is modeled as the Kawasaki particle-vacancy exchange process in the presence of long-range attractive particle-partic

D. A. W. Hutchinson, R. J. Dodd, K. Burnett

We present predictions for the frequencies of collective modes of trapped Bose-condensed $^{87}$Rb atoms at finite temperature. Our treatment includes a self-consistent treatment of the mean-field from finite-$T$ excitations and the anomolous average. This is the first gapless calculation of this type for a trapped Bose-Einstein condensed gas. The correction

Raffaele Guido Della Valle, Elisabetta Venuti

We present Molecular Dynamics (MD), Quasi Harmonic Lattice Dynamics (QHLD) and Energy Minimization (EM) calculations for the crystal structure of Ne, Ar, Kr and Xe as a function of pressure and temperature. New Lennard-Jones (LJ) parameters are obtained for Ne, Kr and Xe to reproduce the experimental pressure dependence of the density. We employ a simple met

Gaia Pedrolli, Alessandro Cuccoli, Alessandro Macchi, Valerio Tognetti

We present a Path Integral Monte Carlo calculation of the first three moments of the displacement-displacement correlation functions of solid neon at different temperatures for longitudinal and transverse phonon modes. The Lennard-Jones potential is considered. The relevance of the quantum effects on the frequency position of the peak and principally on the

Klaus Oerding, Frederic van Wijland

We consider a directed percolation process at its critical point. The probability that the deviation of the global order parameter with respect to its average has not changed its sign between 0 and t decays with t as a power law. In space dimensions d<4 the global persistence exponent theta_p that characterizes this decay is theta_p=2 while for d<4 its value

M. Bezzi, R. Livi

A deterministic cellular automaton rule defined on the Moore neighbourhood is studied as a model of epidemic propagation. The directed nature of the interaction between cells allows one to introduce the dependence on a disorder parameter that determines the fraction of ``in-phase&#39;&#39; cells. Phase-disorder is shown to produce peculiar changes in the dyn

J. M. P. Carmelo, P. D. Sacramento, N. M. R. Peres, D. Baeriswyl

The frequency-dependent conductivity is studied for both the one-dimensional Hubbard model and a model of spinless fermions, using a selection rule, the Bethe ansatz energy eigenstates, and conformal invariance. For densities where the system is metallic the absorption spectrum has two contributions, a Drude peak at ω= 0 separated by a pseudo-gap from a broa

G. Bouzerar, S. Sil

Using the Bond Operator Technique (BOT), we have studied the low energy excitationspectrum of a frustrated dimerized antiferromagnetic Heisenberg chain. In particular, we have compared our analytical results with previous Exact Diagonalizations (ED) data. Qualitatively, the BOT results are in good agreement with the ED data. And even a very good quantitative

A. Perali, C. Grimaldi, L. Pietronero

The nonadiabatic electron-phonon corrections for the superconducting pairing are investigated for a specific tight-binding model corresponding to a 2d square lattice. This permits to investigate the role of various specific properties like the band filling, nesting effects and a realistic van Hove singularity on the superconducting effective pairing beyond M

Francesco Sciortino, Srikanth Sastry, Piero Tartaglia

We calculate local potential energy minima (inherent structures) for a simple model of orthoterphenyl (OTP), from computer simulations over a wide temperature range. We show that the results are very sensitive to the system size. We locate, from the temperature and size dependence of inherent structure energies, a well defined cross-over temperature that cor

S. Artz, M. Schulz, S. Trimper

A non--linear diffusion equation is derived by taking into account hopping rates depending on the occupation of next neighbouring sites. There appears additonal repulsive and attractive forces leading to a changed local mobiltiy. The stationary and the time dependent behaviour of the system are studied based upon the master equation approach. Different to co

Th. Busch, J. R. Anglin, J. I. Cirac, P. Zoller

Fermi inhibition is a quantum statistical analogue for the inhibition of spontaneous emission by an excited atom in a cavity. This is achieved when the relevant motional states are already occupied by a cloud of cold atoms in the internal ground state. We exhibit non-trivial effects at finite temperature and in anisotropic traps, and briefly consider a possi

B. N. J. Persson, E. Tosatti

In a recent paper [Phys. Rev. Lett. 80 (1998) 1690], Krim and coworkers have observed that the friction force, acting on a thin physisorbed layer of N_2 sliding on a lead film, abruptly decreases by a factor of ~2 when the lead film is cooled below its superconductivity transition temperature. We discuss the possible mechanisms for the abruptness of the slid

Aaron R. Dinner, Victor Abkevich, Eugene Shakhnovich, Martin Karplus

The folding ability of a heteropolymer model for proteins subject to Monte Carlo dynamics on a simple cubic lattice is shown to be strongly correlated with the energy gap between the native state and the structurally dissimilar part of the spectrum. We consider a number of estimates of the energy gap that can be determined without simulation, including the g

Glenn Carroll, Mats Rooth

This paper presents an experiment in learning valences (subcategorization frames) from a 50 million word text corpus, based on a lexicalized probabilistic context free grammar. Distributions are estimated using a modified EM algorithm. We evaluate the acquired lexicon both by comparison with a dictionary and by entropy measures. Results show that our model p

Claude R. Canizares, Taotao Fang

The transmission grating spectrometers on AXAF have sufficient sensitivity and energy resolution to detect resonance X-ray absorption lines in the spectra of distant quasars. Such lines would be produced in an ionized, and somewhat chemically enriched component of the inter-galactic medium. The bulk of the baryonic content of the universe at redshifts <=2-3

C. M. Becker, R. A. Remillard, S. A. Rappaport, J. E. McClintock

From 1994 to 1997 we monitored the optical spectrum of RXJ0019.8+2156. This supersoft X-ray source is one of only two accreting white dwarfs in the Galaxy thought to be burning hydrogen on their surface as a consequence of a high rate of mass transfer from a binary companion. Accurate orbital ephemerides are derived from radial velocity measure- ments of HeI

M. J. Church, M. Balucinska-Church, T. Dotani, K. Asai

We report results of analysis of the ASCA observation of 1993, May 7th of the dipping LMXB source XBT 0748-676, and propose a new explanation of the spectral evolution in dipping in this source. We show that the non-dip and dip spectra in several intensity bands are well fitted using the same physical model that we have previously shown gives good explanatio

S. Hubrig

Recent results obtained by various authors on the properties of HgMn stars are reviewed. Substantial progress has been achieved in the study of abundances and isotopic anomalies. The results about the magnetic fields and membership in multiple systems suggest further directions of investigations to be followed in view of answering the question of the develop

Georges Alecian

Each time diffusion of elements is invoked in explaining abundance anomalies in a star, this supposes implicitly that a stratification process is in progress somewhere in that star. This means also, that the element abundances can still be evolving according to the star&#39;s age and fundamental parameters. Moreover, it has been shown that the superficial ab

F. Leone

For the purpose of deriving the helium abundances in chemically peculiar stars, the importance of assuming a correct helium abundance has been investigated for determining the effective temperature and gravity of main sequence B-type stars, making full use of the present capability of reproducing their helium lines. Even if the flux distribution of main sequ

R. Sunyaev, E. Churazov

Observations of the diffuse emission in the 8--22 keV energy range, elongated parallel to the Galactic plane (Sunyaev et al. 1993) and detection of the strong 6.4 keV fluorescent line with $\sim$ 1 keV equivalent width from some giant molecular clouds (e.g. Sgr B2) in the Galactic Centre region (Koyama 1994) suggest that the neutral matter of these clouds is

M. J. Gelbmann

Element abundances of three roAp stars, HD 166473, HD 203932, and HD 217522, were determined using Kurucz model atmospheres with metal abundances scaled to solar ones and the results were compared with data from the literature concerning three further roAp stars, normal B and A stars and two lambda Bootis stars. Up to 38 elements could be identified and ther

D. W. Kurtz

Three topics are discussed: 1) Photometric observations of the rapidly oscillating Ap stars have shown that the pulsation amplitude drops dramatically as a function of wavelength from the blue to the red. A theoretical derivation, plus modelling, indicates that this is because the vertical wavelength of the pulsation mode is short compared to the scale heigh

Bernhard Geiger, Peter Schneider

In a previous paper we investigated means for constraining the mass distribution of cluster galaxies by weak lensing. We concluded that a comprehensive method should treat the lensing effects of individual cluster galaxies and those resulting from a general cluster component simultaneously. To this end we now develop a non-parametric maximum likelihood clust

H. M. Maitzen, M. Rode, E. Paunzen

The search for chemically peculiar (CP) stars in open clusters using photoelectric photometry sampling the presence of the characteristic flux depression feature at 5200A via the Delta a-system (Maitzen 1976) has so far delivered data for objects usually no more distant than 1000 pc from the Sun. If one intends to study the presence of CP stars at larger dis

K. Stepien

Observational data on rotation of Ap stars suggest that the bulk of their rotation rates form a separate Maxwellian distribution with an average value 3-4 times lower than the normal star distribution. No evidences for a significant angular momentum (AM) loss on the main sequence (MS) have been found. It is thus concluded that Ap stars must lose a large frac

Erik Kuulkers

For the first time we have performed a detailed study of the X-ray, optical and infra-red light curves of the 1975/1976 outburst of the famous black-hole transient A0620-00 (Nova Mon 1975, V616 Mon). During the various stages of its outburst the X-rays lag the optical by ~5-20 days. Moreover, the activity associated with the secondary maximum started even ea

M. Gerbaldi, R. Faraggiana, R. Burnage, F. Delmas

The determination of the ``Fundamental Parameters&#39;&#39; T_eff and log g for a set of dwarf A0-type stars is discussed in terms of consistency when comparing these values determined through different methods. The position of these stars in the HR diagram are discussed, taking into account the HIPPARCOS data. A large number of binary stars with components

E. Pointecouteau, M. Giard, D. Barret

Measurements of the Sunyaev-Zeldovich (hereafter SZ) distorsion of the cosmic microwave background can give interesting physical informations on clusters of galaxies, provided that the electronic temperature of the gas is known. Previous attempts to do so have used the electronic temperature determination obtained from the X-ray spectra. However, if the inte

I. Tkachev, S. Khlebnikov, L. Kofman, A. Linde

We investigate nonthermal phase transitions that may occur after post-inflationary preheating in a simple model of a two-component scalar field with the effective potential $λ(ϕ_i^2 - {\rm v}^2)^2/4$, where $ϕ_1$ is identified with the inflaton field. We use three-dimensional lattice simulations to investigate the full nonlinear dynamics of the model. Fluctu

Andreas S. Kronfeld

It is widely believed that the pole mass of a quark is infrared-finite and gauge-independent to all orders in perturbation theory. This seems not to have been proved in the literature. A proof is provided here.

MILC Collaboration, Claude Bernard, Tom Blum, Carleton DeTar

We calculate the light quark spectrum of lattice QCD in the quenched approximation using Kogut-Susskind quarks. By combining results for different lattice spacings, several volumes and five quark masses, we are able to take the light quark mass, infinite volume, continuum limit. When we use non-linear chiral extrapolations, we find that the nucleon to rho ma

N. D. Hari Dass, Tabish Qureshi

Recently proposed idea of &#34;protective&#34; measurement of a quantum state is critically examined, and generalized. Earlier criticisms of the idea are discussed and their relevance to the proposal assessed. Several constraints on measuring apparatus required by &#34;protective&#34; measurements are discussed, with emphasis on how they may restrict their e

Ernest Ma

In the minimal standard electroweak gauge model, there is an effective dimension-five operator which generates neutrino masses, and it has only three tree-level realizations. One is the canonical seesaw mechanism with a right-handed neutrino. Another is having a heavy Higgs triplet as recently proposed. The third is to have a heavy Majorana fermion triplet,

S. Esipov, I. Vaysburd

We analyse derivative securities whose value is NOT a deterministic function of an underlying which means presence of a basis risk at any time. The key object of our analysis is conditional probability distribution at a given underlying value and moment of time. We consider time evolution of this probability distribution for an arbitrary hedging strategy (dy

Lloyd Knox, Roman Scoccimarro, Scott Dodelson

Hydrogen atoms in the Universe that initially formed at redshift z = 1100 were reionized at 5 < z < 60. It is likely that this transition proceeded through a mixed phase of partial ionization. We develop an analytic approach to calculating the effect on the cosmic microwave background (CMB) of Thomson scattering off this inhomogeneous distribution of free el

Joshua C. Long, Hilton W. Chan, John C. Price

We review the experimental constraints on additional macroscopic Yukawa forces for interaction ranges below 1 cm., and summarize several theoretical predictions of new forces in this region. An experiment using 1 kHz mechanical oscillators as test masses should be sensitive to much of the parameter space covered by the predictions.

Stefano Forte, Jose I. Latorre

We present a proof of the irreversibility of renormalization group flows, i.e. the c-theorem for unitary, renormalizable theories in four (or generally even) dimensions. Using Ward identities for scale transformations and spectral representation arguments, we show that the c-function based on the trace of the energy-momentum tensor (originally suggested by C

Frederic Mila

We show that non-frustrated and frustrated ladders in a magnetic field can be systematically mapped onto an XXZ Heisenberg model in a longitudinal magnetic field in the limit where the rung coupling is the dominant one. This mapping is valid in the critical region where the magnetization goes from zero to saturation. It allows one to relate the properties of

A. V. Smilga

Taking into account the quadratic in mass terms in the effective chiral lagrangian, we show that, at θ\sim π, the theory with 2 light quarks of equal mass involves two degenerate vacuum states separated by a barrier. For three flavors, the energy barrier between two vacua appears already in the leading order in mass. This corresponds to the first order phase

P. Csizmadia, T. Csorgo, B. Lukacs

New solutions are found for the non-relativistic hydrodynamical equations. These solutions describe expanding matter with a Gaussian density profile. In the simplest case, thermal equilibrium is maintained without any interaction, the energy is conserved, and the process is isentropic. More general solutions are also obtained that describe explosions driven

K. Langfeld, O. Tennert, M. Engelhardt, H. Reinhardt

Recent lattice calculations performed at zero temperature and in the maximal center gauge indicate that quark confinement can be understood in this gauge as due to fluctuations in the number of magnetic vortices piercing a given Wilson loop. This development has led to a revival of the vortex condensation theory of confinement. For a SU(2) gauge group, we sh

A. N. Aliev, Y. Nutku

We construct the explicit form of three almost complex structures that a Riemannian manifold with self-dual curvature admits and show that their Nijenhuis tensors vanish so that they are integrable. This proves that gravitational instantons with self-dual curvature admit hyper-Kähler structure. In order to arrive at the three vector valued 1-forms defining a

N. Saito

The PHENIX experiment at RHIC has extended its scope to cover spin physics using polarized proton beams. The major goals of the spin physics at RHIC are elucidation of the spin structure of the nucleon and precision tests of the symmetries. Sensitivities of the spin physics measurements with the PHENIX detector system are reviewed.

Fabio Gavarini

Let $\hat{\frak g}$ be an untwisted affine Kac-Moody algebra. The quantum group $U_h(\hat{\frak g})$ (over $\mathbb{C}[[h]]$) is known to be a quasitriangular Hopf algebra: in particular, it has a universal $ R $--matrix, which yields an $ R $--matrix for each pair of representations of $U_h(\hat{\frak g})$. On the other hand, the quantum group $U_q(\hat{\fr

Dirk Helbing, Bernardo A. Huberman

Recent advances in multiagent simulations have made possible the study of realistic traffic patterns and allow to test theories based on driver behaviour. Such simulations also display various empirical features of traffic flows, and are used to design traffic controls that maximise the throughput of vehicles in heavily transited highways. In addition to its

A. Langari

The anisotropic s=1/2 anti-ferromagnetic Heisenberg chain in the presence of an external magnetic field is studied by using the standard quantum renormalization group. We obtain the critical line of the transition from partially magnetized (PM) phase to the saturated ferromagnetic (SFM) phase. The crossover exponent between the PM phase and anti-ferromagneti

Denis Bernard, Krzysztof Gawedzki

We analyze the stochastic scaling laws arising in the invicid limit of the decaying solutions of the Burgers equation. The linear scaling of the velocity structure functions is shown to reflect the domination by shocks of the long-time asymptotics. We exhibit new self-similar statistics of solutions describing phases with diluted shocks. Some speculations ar

Pedro F. Gonzalez-Diaz

We show that the instability of the singular Vilenkin instanton describing the creation of an open universe can be avoided using, instead of a minimally coupled scalar field, an axionic massless scalar field which gives rise to the Giddings-Strominger instanton. However, if we replace the singularity of the Hawking Turok instanton for an axionic wormhole som

Alan Dow, Klaas Pieter Hart

We prove that every continuum of weight aleph_1 is a continuous image of the Cech-Stone-remainder R^* of the real line. It follows that under CH the remainder of the half line [0,infty) is universal among the continua of weight c --- universal in the `mapping onto&#39; sense. We complement this result by showing that 1) under MA every continuum of weight les

W. H. Tang, J. Smit

We give arguments that in the 1+1 dimensional abelian Higgs model the classical approximation can be good for the leading high temperature behavior of real time processes. The Chern-Simons diffusion rate (`sphaleron rate&#39;) is studied numerically in this approximation. New results at high temperature show a $T^{2/3}$ behavior of the rate at sufficiently s

Miguel Navarro

Rules of quantization and equations of motion for a finite-dimensional formulation of Quantum Field Theory are proposed which fulfill the following properties: a) both the rules of quantization and the equations of motion are covariant; b) the equations of evolution are second order in derivatives and first order in derivatives of the space-time co-ordinates

R. Banerjee, S. Ghosh

The fundamental importance of the chiral oscillator is elaborated. Its quantum invariants are computed. As an application the Zeeman effect is analysed. We also show that the chiral oscillator is the most basic example of a duality invariant model, simulating the effect of the familiar electric-magnetic duality.

H. B. Nersisyan, A. V. Hovhannisyan, C. Deutsch

The energy loss by a test gyratory particle in a cold plasma in the presence of homogeneous magnetic field is considered. Analytical and numerical results for the rate of energy loss are presented. This is done for strong and weak fields (i. e., when the electron cyclotron frequency is either higher, or smaller than the plasma frequency), and in case, when t

C. G. Bao

The feature of the low-lying spectrum and a complete set of quantum numbers of the (e+e+e-e-) system have been deduced based on symmetry consideration. The existence of a low odd-parity L=1 excited state with the spins of the two electrons coupled to s1=1 and the two positrons coupled to s2=0 (or s1=0 and s2=1) and a low even-parity L=0 excited state with s1

Rebecca Surman, Jonathan Engel

We use the Quasiparticle Random Phase Approximation to include the effects of low-lying Gamow-Teller and first forbidden strength in neutrino capture by very neutron-rich nuclei with N = 50, 82, or 126. For electron neutrinos in what is currently considered the most likely r-process site the capture cross sections are two or more times previous estimates. We

Sarira Sahu

The axial vector coupling constants of the $β$ decay processes of neutron and hyperon are calculated in SU(3) chiral colour dielectric model (CCDM). Using these axial coupling constants of neutron and hyperon, in CCDM we calculate the integrals of the spin dependent structure functions for proton and neutron. Our result is similar to the results obtained by

Giovanni Modanese

We propose a method for the approximate computation of the Green function of a scalar massless field subjected to potential barriers of given size and shape in spacetime. The potential of the barriers has the form V(phi)=xi(phi^2-phi_0^2)^2; xi is very large and phi_0 very close to zero, the product (xi phi_0^2) being finite and small. This is equivalent to

Hasan Gumral

A Poisson structure on the time-extended space R x M is shown to be appropriate for a Hamiltonian formalism in which time is no more a privileged variable and no a priori geometry is assumed on the space M of motions. Possible geometries induced on the spatial domain M are investigated. An abstract representation space for sl(2,R) algebra with a concrete phy

Hasan Gumral

The motion of an incompressible fluid in Lagrangian coordinates involves infinitely many symmetries generated by the left Lie algebra of group of volume preserving diffeomorphisms of the three dimensional domain occupied by the fluid. Utilizing a 1+3-dimensional Hamiltonian setting an explicit realization of this symmetry algebra is constructed recursively.

Dominique Foata, Doron Zeilberger

By practicing the philosophy of our beloved late master, Marco Schutzenberger, to whose memory this article is dedicated, we give an insightful bijective proof of the three-term recurrence satisfied by the Hipparchus-Schroeder numbers 1,1,3,11,45,197,903, ...

Donald M. Davis

We compute the 3-primary v1-periodic homotopy groups of the exceptional Lie group E7. Now E8 at the primes 3 and 5 is the only compact simple Lie group whose odd-primary v1-periodic homotopy groups remian to be computed. The main work is computing the unstable Novikov spectral sequence of ΩE7/Sp(2). Showing that this converges to v1-periodic homotopy groups

E. V. Ferapontov

An explicit construction of surfaces with flat normal bundle in the Euclidean space (unit hypersphere) in terms of solutions of certain linear system is proposed. In the case of 3-space our formulae can be viewed as the direct Lie sphere analog of the generalized Weierstrass representation of surfaces in conformal geometry or the Lelieuvre representation of

E. V. Ferapontov

It is demonstrated that the stationary Veselov-Novikov (VN) and the stationary modified Veselov-Novikov (mVN) equations describe one and the same class of surfaces in projective differential geometry: the so-called isothermally asymptotic surfaces, examples of which include arbitrary quadrics and cubics, quartics of Kummer, projective transforms of affine sp

Tom H. Koornwinder

This paper argues that automated proofs of identities for non-terminating hypergeometric series are feasible by a combination of Zeilberger&#39;s algorithm and asymptotic estimates. For two analogues of Saalschütz&#39; summation formula in the non-terminating case this is illustrated.

Sonia Paban, Savdeep Sethi, Mark Stern

We consider quantum mechanical gauge theories with sixteen supersymmetries. The Hamiltonians or Lagrangians characterizing these theories can contain higher derivative terms. In the operator approach, we show that the free theory is essentially the unique abelian theory with up to four derivatives in the following sense: any small deformation of the free the

Javier Borlaf

It is shown how some field theories in the target-space induce the splitting of the space-time into a continuous of branes, which can be p-branes or D-branes depending on what the field theory it is. The basic symmetry underlying the construction is used to build an invariant action, which is proved to be off-shell identical to the p-brane (D-brane) action.

Stephen Berman, Jacek Szmigielski

We construct an irreducible representation for the extended affine algebra of type $sl_2$ with coordinates in a quantum torus. We explicitly give formulas using vertex operators similar to those found in the theory of the infinite rank affine algebra $A_{\infty}$.

Edward Teo

Recent work has uncovered a correspondence between theories in anti-de Sitter space, and those on its boundary. This has important implications for black holes in string theory which have near-horizon AdS geometries. Using the effective coupling to the boundary conformal field theory, I compute the low-energy, s-wave absorption cross-sections for a minimally

Martin Lavelle, David McMullan

Asymptotic freedom arises from the dominance of anti-screening over screening in non-abelian gauge theories. In this paper we will present a simple and physically appealing derivation of the anti-screening contribution to the interquark potential. Our method allows us to identify the dominant gluonic distribution around static quarks. Extensions are discusse

L. Burakovsky

We show that Regge phenomenology is consistent with the only universal scaling law for hadron masses, M^\ast /M=(α^{&#39;}/α^{&#39;\ast})^{1/2}, where asterisk indicates a finite-temperature quantity. Phenomenological models further suggest the following expression of the above scaling in terms of the temperature-dependent gluon condensate: M^\ast / M = (α^&