September 1996 arXiv papers — page 8

M. Jarrell, Hanbin Pang, D. L. Cox, F. Anders

The paramagnetic phase of the two-channel Kondo lattice model is examined with a Quantum Monte Carlo simulation in the limit of infinite dimensions. We find non-Fermi-liquid behavior at low temperatures including a finite low-temperature single-particle scattering rate, no Fermi distribution discontinuity, and zero Drude weight. Both the optical and quasipar

C. Batlle, E. Fossas, G. Olivar

Time-delay autosynchronization (TDAS) can be used to stabilize unstable periodic orbits in dynamical systems. The technique involves continuous feedback of signals delayed by the orbit's period. One variant, ETDAS, uses information further in the past. In both cases, the feedback signal vanishes on the target periodic orbit and hence the stabilized perio

G. J. Chaitin

I'll outline the latest version of my limits of math course. The purpose of this course is to illustrate the proofs of the key information-theoretic incompleteness theorems of algorithmic information theory by means of algorithms written in a specially designed version of LISP. The course is now written in HTML with Java applets, and is available at http

Eric G. Blackman, Insu Yi, George B. Field

We discuss the possibility that gamma-ray bursts may result from cosmological relativistic blob emitting neutron star jets that precess past the line of sight. Beaming reduces the energy requirements, so that the jet emission can last longer than the observed burst duration. One precession mode maintains a short duration time scale, while a second keeps the

Romeel Davé, Lars Hernquist, David Weinberg, Neal Katz

We use an automated Voigt-profile fitting procedure to extract statistical properties of the Ly$α$ forest in a numerical simulation of an $Ω=1$, cold dark matter (CDM) universe. Our analysis method is similar to that used in most observational studies of the forest, and we compare the simulations to recently published results derived from Keck HIRES spectra.

R. N. Ogley, S. J. Bell Burnell, S. J. Newell

Following the recent discovery that Cyg X-3 exhibits superluminal motion, the implications of superluminal expansion and contraction are investigated. We propose that the effect is due to either a propagating photon pattern or to outwardly moving shells illuminated by an intense beam of radiation.

John L. Tonry, John P. Blakeslee, Edward A. Ajhar, Alan Dressler

We describe a program of surface brightness fluctuation (SBF) measurements for determining galaxy distances. This paper presents the photometric calibration of our sample and of SBF in general. Basing our zero point on observations of Cepheid variable stars, we find that the absolute SBF magnitude in the Kron-Cousins I band correlates well with the mean (V-I

R. N. Ogley, S. J. Bell Burnell, R. P. Fender

We present UKIRT infrared images of the X-ray binary Cygnus X-3. We address the possibility of extended infrared emission and show that it could be either warm circumstellar material or a star near the binary's line of sight.

Slavek Rucinski

A brief summary of properties of the contact binaries is presented, with the goal to stress the unsolved problems of their formation and evolution as well as their potential contribution to studies of Galactic stellar populations. The first results from the OGLE survey, where the contact binaries contribute a full two thirds among 933 eclipsing binary stars,

Peter L. Biermann

Our Galaxy is the largest nuclear interaction experiment which we know, because of the interaction between cosmic ray particles and the interstellar material. Cosmic rays are particles, which have been accelerated in the Galaxy or in extragalactic space. Cosmic rays come as protons, electrons, heavier nuclei, and their antiparticles. Up to energies up to som

R. Capuzzo-Dolcetta, F. Sori

A young open cluster is a 2-phase system: an ensemble of stars move in a gaseous medium (the mother molecular cloud). The dynamics and thermodynamics of the system, and so its evolution and final fate (is it stable or unstable?), strongly depends on the mutual feedback between gas and stars. We present an approach which consists in a (simplified) model where

G. S. Tucker, H. P. Gush, M. Halpern, W. Towlson

A new instrument, BAM (Balloon-borne Anisotropy Measurement), designed to measure cosmic microwave background (CMB) anisotropy at medium angular scales was flown for the first time in July of 1995. BAM is unique in that it uses a cryogenic differential Fourier transform spectrometer coupled to a lightweight off-axis telescope. The very successful first fligh

Carlos Simpson

We propose a generalization of Artin's definition of algebraic stack, which we call {\em geometric $n$-stack}. The main observation is that there is an inductive structure to the definition whereby the ingredients for the definition of geometric $n$-stack involve only $n-1$-stacks and so are already previously defined. We use this inductive structure to

D. P. Arovas, J. A. Freire

The coupling of vortices to phonons in a superfluid is a gauge coupling dictated by topology. The density and current response to a moving vortex are computed and contrasted with the standard backflow picture. Exploiting the analogy to (2+1)-dimensional electrodynamics, we compute the effective vortex mass $M(ω)$ and find it to be logarithmically divergent i

J. Amundson, G. Anderson, H. Baer, J. Bagger

We provide a mini-guide to some of the possible manifestations of weak scale supersymmetry. For each of six scenarios we provide a brief description of the theoretical underpinnings, the adjustable parameters, a qualitative description of the associated phenomenology at future colliders, comments on how to simulate each scenario with existing event generator

C. A. Katz, C. B. Moore, J. N. Hewitt

The four-image gravitational lens system MG0414+0534 was observed with the VLA at 1.4, 5, 8, 15, and 22 GHz. The 15 and 22 GHz images reveal structure in the components which is consistent with that seen at other wavelengths. There was no detection of other extended emission, nor were there detections of the lensing galaxy or the "component x" seen i

D. J. Broadhurst, D. Kreimer

It is found that the number, $M_n$, of irreducible multiple zeta values (MZVs) of weight $n$, is generated by $1-x^2-x^3=\prod_n (1-x^n)^{M_n}$. For $9\ge n\ge3$, $M_n$ enumerates positive knots with $n$ crossings. Positive knots to which field theory assigns knot-numbers that are not MZVs first appear at 10 crossings. We identify all the positive knots, up

H. Lu. C. N. Pope, K. -W. Xu

We construct multi-center solutions for charged, dilatonic, non-extremal black holes in D=4. When an infinite array of such non-extremal black holes are aligned periodically along an axis, the configuration becomes independent of this coordinate, which can therefore be used for Kaluza-Klein compactification. This generalises the vertical dimensional reductio

C. Figueira de Morisson Faria, A. Fring, R. Schrader

We investigate analytical expressions for the upper and lower bounds for the ionization probability through ultra-intense shortly pulsed laser radiation. We take several different pulse shapes into account, including in particular those with a smooth adiabatic turn-on and turn-off. For all situations for which our bounds are applicable we do not find any evi

Dima Mozyrsky, Vladimir Privman

The classical signal splitting and copying are not possible in quantum mechanics. Specifically, one cannot copy the basis up and down states of the input (I) two-state system (qubit, spin) into the copy (C) and duplicate-copy (D) two-state systems if the latter systems are initially in an arbitrary state. We consider instead a quantum evolution in which the

Joonhyun Yeo, M. A. Moore

We study the Ginzburg-Landau model with a nonlocal quartic term as a simple phenomenological model for superconductors in the presence of coupling between the vortex lattice and the underlying crystal lattice. In mean-field theory, our model is consistent with a general oblique vortex lattice ranging from a triangular lattice to a square lattice. This simple

Jozef Dodziuk, Varghese Mathai

In this paper, we prove that the $L^2$ Betti numbers of an amenable covering space can be approximated by the average Betti numbers of a regular exhaustion, proving a conjecture that we made in an earlier paper. We also prove that an arbitrary amenable covering space of a finite simplicial complex is of determinant class.

Lorenzo Fatibene, Marco Ferraris, Mauro Francaviglia, Marco Godina

A new formalism for spinors on curved spaces is developed in the framework of variational calculus on fibre bundles. The theory has the same structure of a gauge theory and describes the interaction between the gravitational field and spinors. An appropriate gauge structure is also given to General Relativity, replacing the metric field with spin frames. Fin

Edward Witten

The quantization law for the antisymmetric tensor field of $M$-theory contains a gravitational contribution not known previously. When it is included, the low energy effective action of $M$-theory, including one-loop and Chern-Simons contributions, is well-defined. The relation of $M$-theory to the $E_8\times E_8$ heterotic string greatly facilitates the ana

P. Zavada

The alternative to the standard formulation of QPM in the infinite momentum frame is suggested. The proposed approach does not require any extra assumptions in addition, consistently takes into account the parton transversal momenta and does not prefer any special reference system. The standard approach is involved as a limiting case. In the result the modif

J. Greiner, B. A. Harmon, W. S. Paciesas, E. H. Morgan

A comparison of ROSAT observations with simultaneous BATSE monitoring data shows a different intensity evolution in the soft and hard X-ray band of GRS 1915+105 since 1992. In addition, fits of simultaneous ROSAT/BATSE spectra require more than one spectral component. A short description of results of RXTE pointed observations of GRS 1915+105 since April 199

Soo-Jong Rey

Super--inflation driven by dilaton/moduli kinetic energy is naturally realized in compactified string theory. Discussed are selected topics of recent development in string inflationary cosmology: kinematics of super-inflation, graceful exit triggered by quantum back reaction, and clasical and quantum power spectra of density and metric perturbations.

Wen-Xiu Ma, Kam-Shun Li

A hierarchy of first-degree time-dependent symmetries is proposed for Dirac soliton hierarchy and their commutator relations with time-dependent symmetries are exhibited. Meantime, a hereditary structure of Dirac soliton hierarchy is elucidated and a Lax operator algebra associated with Virasoro symmetry algebra is given.

Murray Gerstenhaber, Anthony Giaquinto

We define a new class of unitary solutions to the classical Yang-Baxter equation (CYBE). These ``boundary solutions'' are those which lie in the closure of the space of unitary solutions to the modified classical Yang-Baxter equation (MCYBE). Using the Belavin-Drinfel'd classification of the solutions to the MCYBE, we are able to exhibit new fami

Bernhard Drabant, Alfons Van Daele

We define and investigate pairings of multiplier Hopf algebras. It is shown that two dually paired regular multiplier Hopf ($*$-)algebras $A$ and $B$ yield a quantum double multiplier Hopf ($*$-)algebra which is again regular. Integrals on $A$ and $B$ induce an integral on the quantum double. The results generalize pairing and quantum double construction fro

Craig D. Roberts

Determinations of the gluon propagator in the continuum and in lattice simulations are compared. A systematic truncation procedure for the quark Dyson-Schwinger and bound state Bethe-Salpeter equations is described. The procedure ensures the flavour-octet axial-vector Ward identity is satisfied order-by-order, thereby guaranteeing the preservation of Goldsto

Jorge Piekarewicz

Nuclear matter is modeled directly in terms of its constituent quarks. A many-body string-flip potential is used that confines quarks within hadrons, enables the hadrons to separate without generating van der Waals forces, and is symmetric in all quark coordinates. We present variational Monte Carlo results for the ground-state properties of large, three-dim

M. -Th. Huett, A. I. Milstein, M. Schumacher

The universal curve $σ/A$ of nuclear photoabsorption is investigated within a Fermi gas model of nuclear matter. An energy range from pion threshold up to 400 MeV is considered. The interactions between nucleon, pion, $Δ$-isobar and photon are considered in the non-relativistic approximation with corrections of the order $1/M$ taken into account with respect

Mitch Rudominer

Let kappa be the least ordinal alpha such that L_{alpha}(R) is admissible. Let A be the set of reals x such that x is ordinal definable in L_α(R), for some alpha<kappa. It is well known that (assuming determinacy) A is the largest countable inductive set of reals. Let T be the following theory: ZFC - Replacement + &#34;There exists $ω$ Woodin cardinals which

Alessandro Andretta, Alberto Marcone

We study some natural sets arising in the theory of ordinary differential equations in one variable from the point of view of descriptive set theory and in particular classify them within the Borel hierarchy. We prove that the set of Cauchy problems for ordinary differential equations which have a unique solution is $Π^0_2$-complete and that the set of Cauch

C. Wiesendanger

The loop-expansion of the effective potential in the $O(N)$-symmetric $ϕ^4$-model contains generically two types of large logarithms. To resum those systematically a new minimal two-scale subtraction scheme $\tMS$ is introduced in an $O(N)$-invariant generalization of $\MS$. As the $\tMS$ beta functions depend on the renormalization scale-ratio a large logar

Christopher Ford

The standard MS renormalization prescription is inadequate for dealing with multiscale problems. To illustrate this, we consider the computation of the effective potential in the Higgs-Yukawa model. It is argued that the most natural way to deal with this problem is to introduce a 2-scale renormalization group. We review various ways of implementing this ide

Niclas Wyllard

In this paper we introduce a class of generalized supersymmetric Toda field theories. The theories are labeled by a continuous parameter and have $N=2$ supersymmetry. They include previously known $N=2$ Toda theories as special cases. Using the WZNW -->Toda reduction approach we obtain a closed expression for the bracket of the associated ${\cal W}$ algebras

J&#34;urgen Fuchs, Christoph Schweigert

We show that the WZW fusion rings at finite levels form a projective system with respect to the partial ordering provided by divisibility of the height, i.e. the level shifted by a constant. From this projective system we obtain WZW fusion rings in the limit of infinite level. This projective limit constitutes a mathematically well-defined prescription for t

G. P. Korchemsky

We study the properties of color-singlet Reggeon compound states in multicolor high-energy QCD in four dimensions. Their spectrum is governed by completely integrable (1+1)-dimensional effective QCD Hamiltonian whose diagonalization within the Bethe Ansatz leads to the Baxter equation for the Heisenberg spin magnet. We show that nonlinear WKB solution of the

Holger Gies

Within the framework of semiclassical QCD approximations the short distance behavior of two static color charges in (2+1)-dimensional QCD is discussed. A classical linearization of the field equations is exhibited and leads to analytical results producing the static potential. Beyond the dominant classical part proportional to ln lambda R, QCD contributions

H. T. Ozer

Casimir W-algebras are shown to exist in such a way that the conformal spins of primary(generating) fields coincide with the orders of independent Casimir operators. We show here that this coincidence can be extended further to the case that these generating fields have the same eiginvalues with the Casimir operators.

Everton M. C. Abreu, Nelson R. F. Braga

It has recently been shown that the Field Antifield quantization of anomalous irreducible gauge theories with closed algebra can be represented in a BRST superspace where the quantum action at one loop order, including the Wess Zumino term, and the anomalies show up as components of the same superfield. We show here how the Chiral Schwinger model can be repr

Phil E. Gibbs

I consider an algebraic construction of creation and annihilation operators for superstring and p-brane parton models. The result can be interpreted as a realisation of multiple quantisation and suggests a relationship between quantisation and dimension. The most general algebraic form of quantisation may eventually be expressed in the language of category t

H. Jallouli, H. Sazdjian

Using connection with quantum field theory, the infinitesimal covariant abelian gauge transformation laws of relativistic two-particle constraint theory wave functions and potentials are established and weak invariance of the corresponding wave equations shown. Because of the three-dimensional projection operation, these transformation laws are interaction d

MiniMax Collaboration

In order to analyze data on joint charged-particle/photon distributions from an experimental search (T-864, MiniMax) for disoriented chiral condensate (DCC) at the Fermilab Tevatron collider, we have identified robust observables, ratios of normalized bivariate factorial moments, with many desirable properties. These include insensitivity to many efficiency

Frank E. Paige

Some possible methods to determine at the LHC masses of SUSY particles are discussed.

G. T. Bodwin, D. K. Sinclair, S. Kim

We calculate the NRQCD matrix elements for the decays of the lowest-lying S- and P-wave states of charmonium and bottomonium in quenched lattice QCD. We also compute the one-loop relations between the lattice and continuum matrix elements.

Katherine Freese, Marc Kamionkowski

Kane and Wells recently argued that collider data point to a Higgsino-like lightest supersymmetric partner which would explain the dark matter in our Galactic halo. They discuss direct detection of such dark-matter particles in laboratory detectors. Here, we argue that such a particle, if it is indeed the dark matter, might alternatively be accessible in exp

R. Akhoury, L. Stodolsky, V. I. Zakharov

We consider perturbative expansions in theories with an infrared cutoff $λ$. The infrared sensitive pieces are defined as terms nonanalytic in the infinitesimal $λ^2$ and powers of this cutoff characterize the strength of these infrared contributions. It is argued that the sum over the initial and final degenerate ( as $λ\to 0$) states which is required by t

William B. Kilgore

I report results from a next-to-leading order event generator of purely gluonic jet production. This calculation, is the first step in the construction of a full next-to-leading order calculation of three jet production at hadron colliders.

D. Boyanovsky, H. J. de Vega, R. Holman

Reply to the comment by L. Kofman, A. Linde and A.A. Starobinsky (hep-ph/9608341) to our article ``Analytic and Numerical Study of Preheating Dynamics&#39;&#39; (hep-ph/9608205).

O. Nachtmann

We discuss various ideas on the nonperturbative vacuum structure in QCD. The stochastic vacuum model of Dosch and Simonov is presented in some detail. We show how this model produces confinement. The model incorporates the idea of the QCD vacuum acting like a dual superconductor due to an effective chromomagnetic monopole condensate. We turn then to high ene

A. Jakovac, A. Patkos

High temperature reduction of the SU(2) Higgs model is realised by partially integrating its partition function. Various approximate forms of the effective theory resulting from the integration over nonstatic fields and the static electric potential are analysed. Also non-polynomial and non-local terms are allowed. Consistency of the perturbative solution is

D. Indumathi, Wei Zhu

The effects of nuclear binding on nuclear structure functions have so far been studied mainly at fixed target experiments, and there is currently much interest in obtaining a clearer understanding of this phenomenon. We use an existing dynamical model of nuclear structure functions, that gives good agreement with current data, to study this effect in a kinem

D. Indumathi

The recent high statistics NMC data on the Tin to Carbon structure function ratio seems to indicate, for the first time, a significant $Q^2$ dependence, especially at small values of Bjorken $x$, $x < 0.05$, and $Q^2 > 1 GeV^2$. Pure leading twist, perturbative QCD--based predictions, which are consistent with the free nucleon data, yield a fairly flat ratio

R. Narayanan, H. Neuberger

There exist chiral gauge models in two dimensions that have massless composite fermions. Two examples are presented and it is suggested that they be accepted as benchmark test-cases for generic proposals of non-perturbatively regulating chiral gauge theories in any dimension. We apply the overlap to the simpler of the two benchmarks and present the results o

Erhard Seiler, Karim Yildirim

An action with $n$ parameters, which generalizes the $O(N) - R P^{N-1}$ -model, is considered in one dimension for general $N$. We use asymptotic expansion techniques to determine where the model becomes critical and show that for the actions considered there exists a family of hypersurfaces whose asymptotic behaviour determines a one-parameter family of new

David Hochberg, Juan Pérez-Mercader

We are able to characterize a 2--dimensional classical fluid sharing some of the same thermodynamic state functions as the Schwarzschild black hole. This phenomenological correspondence between black holes and fluids is established by means of the model liquid&#39;s pair-correlation function and the two-body atomic interaction potential. These latter two fun

Sergiu I. Vacaru

We review the geometric setting of the field theory with locally anisotropic interactions. The concept of locally anisotropic space is introduced as a general one for various type of extensions of Lagrange and Finsler geometry and higher dimension (Kaluza--Klein type) spaces. The problem of definition of spinors on generalized Finsler spaces is solved in the

P. Bak, M. Paczuski, M. Shubik

Large variations in stock prices happen with sufficient frequency to raise doubts about existing models, which all fail to account for non-Gaussian statistics. We construct simple models of a stock market, and argue that the large variations may be due to a crowd effect, where agents imitate each other&#39;s behavior. The variations over different time scale

Thomas Strohm, Manuel Cardona

Superconductivity induced structures in the electronic Raman spectra of high-Tc superconductors are computed using the results of ab initio LDA-LMTO three-dimensional band structure calculations via numerical integrations of the mass fluctuations, either in the whole 3D Brillouin zone or limiting the integrations to the Fermi surface. The results of both cal

Serge Galam

Bethe approximation is shown to violate Bravais lattices translational invariance. A new scheme is then presented which goes over the one-site Weiss model yet preserving initial lattice symmetry. A mapping to a one-dimensional finite closed chain in an external field is obtained. Lattice topology determines the chain size. Using recent results in percolation

P. Czerner, U. Ritschel

Motivated by recent experimental activities on surface critical phenomena, we present a detailed theoretical study of the near-surface behavior of the local order parameter m(z) in Ising-like spin systems. Special attention is paid to the crossover regime between ``ordinary&#39;&#39; and ``normal&#39;&#39; transition in the three-dimensional semi-infinite Is

Andrei D. Zaikin, Dmitrii S. Golubev, Anne van Otterlo, Gergely T. Zimanyi

We present a microscopic study of the quantum fluctuations of the superconducting order parameter in thin homogeneous superconducting wires at all temperatures below $T_C$. The rate of quantum phase slip processes determines the resistance $R(T)$ of the wire, which is observable in very thin wires, even at low temperature. Furthermore, we predict a new low t

Erwin Frey, Leon Balents

We study the phase transitions of interacting bosons at zero temperature between superfluid (SF) and supersolid (SS) states. The latter are characterized by simultaneous off-diagonal long-range order and broken translational symmetry. The critical phenomena is described by a long-wavelength effective action, derived on symmetry grounds and verified by explic

Branko P. Stojkovic, David Pines

We establish the applicability to transport phenomena in the cuprate superconductors of a nearly antiferromagnetic Fermi liquid (NAFL) description of the magnetic interaction between planar quasiparticles by using it to obtain the temperature dependent resistivity and Hall conductivity seen experimentally in the normal state. Following a perturbative calcula

N. Bulut, D. J. Scalapino

In weak coupling, the spin gap in doped, even, n-leg periodic Hubbard ladders reflects the energy to break a pair into separate quasiparticles. Here we investigate the structure of the gap within a spin-fluctuation exchange approximation. We also calculate the amplitude for removing a singlet pair from two lattice sites separated by a distance (l_x,l_y), whi

Rohan Mahadevan

We present analytical scaling laws for self-similar advection dominated flows. The spectra from these systems range from 10$^{8}$ - 10$^{20}$ Hz, and are determined by considering cooling of electrons through synchrotron, bremsstrahlung, and Compton processes. We show that the spectra can be quite accurately reproduced without detailed numerical calculations

Paul A. Wiegert, Matt Holman

This paper investigates the long-term orbital stability of small bodies near the central binary of the Alpha Centauri system. Test particles on circular orbits are integrated in the field of this binary for 32000 binary periods or approximately 2.5 Myr. In the region exterior to the binary, particles with semi-major axes less than roughly three times the bin

Martin White, Wayne Hu

We present a pedagogical derivation of the Sachs-Wolfe effect, specifically the factor 1/3 relating the temperature fluctuations to gravitational potentials. The result arises from a cancellation between gravitational redshifts and intrinsic temperature fluctuations which can be derived from a coordinate transformation of the background.

K. Jedamzik, G. M. Fuller

Detections of deuterium in high redshift Lyman limit absorption systems along the line of sight to QSOs promise to reveal the primordial deuterium abundance. At present, the deuterium abundances (D/H) derived from the very few systems observed are significantly discordant. Assuming the validity of all the data, if this discordance does not reflect intrinsic

F. W. Stecker, O. C. De Jager, M. H. Salamon

We suggest that low-redshift XBLs (X-ray selected BL Lacertae objects) may be the only extragalactic gamma-ray sources observable at TeV energies. We use simple physical considerations involving synchrotron and Compton component spectra for blazars to suggest why the observed TeV sources are XBLs, whereas mostly RBLs and FSRQs are seen at GeV energies. These

Robert W. O&#39;Connell, Pamela Marcum

Optical band images of distant (z > 0.5) galaxies, such as those of the Hubble Deep Field, record light from the rest-frame vacuum ultraviolet (< 3000 A). Because the appearance of a galaxy is a very strong function of wavelength, and especially so in the UV, evolutionary studies of distant galaxies can be seriously influenced by a &#34;morphological k-corre

Andrew Cooke, Brian Espey, Bob Carswell

We use a Maximum-Likelihood analysis to constrain the value and evolution of the ionizing background for 2<z<4.5, taking account of possible systematic errors. (The paper has a more detailed abstract)

Dan Abramovich, Jianhua Wang

A new proof of equivariant resolution of singularities under a finite group action in characteristic 0 is provided. We assume we know how to resolve singularities without group action. We first prove equivariant resolution of toroidal singularities. Then we reduce the general case to the toroidal case.

Dan Abramovich

The result in the title is proven, using the Selberg estimate on the leading eigenvalue of the non-Euclidean Laplacian, and the method of conformal volumes of Li and Yau.

J. M. Isidro, A. Mukherjee, J. P. Nunes, H. J. Schnitzer

A new method to obtain the Picard-Fuchs equations of effective $N = 2$ supersymmetric gauge theories in 4 dimensions is developed. It includes both pure super Yang-Mills and supersymmetric gauge theories with massless matter hypermultiplets. It applies to all classical gauge groups, and directly produces a decoupled set of second-order, partial differential

G. G. Pavlov, V. E. Zavlin, J. Truemper, R. Neuhaeuser

We show that an analysis of multiwavelength observations of isolated neutron stars based on neutron star atmosphere models can be used not only to evaluate the neutron star effective temperature, but also to determine chemical composition of its surface. To demonstrate how this new method can be applied to a specific object, we chose the old isolated neutron

Giuseppe Dito, Moshe Flato

We study Abelian generalized deformations of the usual product of polynomials introduced in hep-th/9602016. We construct an explicit example for the case of $su/2$ which provides a tentative of a quantum-mechanical description of Nambu Mechanics on $R^3$. By introducing the notions of strong and weak triviality of generalized deformations, we show that the Z

Saharon Shelah

We prove that colouring of pairs from aleph_2 with strong properties exists. The easiest to state (and quite a well known problem) it solves: there are two topological spaces with cellularity aleph_1 whose product has cellularity aleph_2 ; equivalently we can speak on cellularity of Boolean algebras or on Boolean algebras satisfying the aleph_2-c.c. whose pr

Saharon Shelah

We consider a class K of structures e.g. trees with omega +1 levels, metric spaces and mainly, classes of Abelian groups like the one mentioned in the title and the class of reduced separable (Abelian) p-groups. We say M in K is universal for K if any member N of K of cardinality not bigger than the cardinality of M can be embedded into M . This is a natural

Saharon Shelah

We investigate sigma-entangled linear orders and narrowness of Boolean algebras. We show existence of sigma-entangled linear orders in many cardinals, and we build Boolean algebras with neither large chains nor large pies. We study the behavior of these notions in ultraproducts.

Saharon Shelah

After the main gap theorem was proved (see [Sh:c]), in discussion, Harrington expressed a desire for a finer structure - of finitary character (when we have a structure theorem at all). I point out that the logic L_{infty,aleph_0}(d.q.) (d.q. stands for dimension quantifier) does not suffice: e.g., for T=Th(lambda x 2^ω,E_n)_{n<omega} where (alpha,eta)E_n(be

S. Mrenna

SPYTHIA is an event level Monte Carlo program which simulates particle production and decay at lepton and hadron colliders in the Minimal Supersymmetric Standard Model (MSSM). It is an extension of PYTHIA 5.7, with all of its previous capabilities. This paper is meant to supplement the PYTHIA/JETSET user manual, providing a description of the new particle sp

A. Kobakhidze

The generalization of the &#34;custodial symmetry&#34; mechanism which leads to the natural (without fine tuning) explanation of the doublet-triplet hierarchy is suggested in the frames of extended $SU(N\geq 8)$ SUSY GUTs. It is shown also that such type of SUSY GUT can predict the value of strong gauge coupling constant $α_S(M_Z)$ consistent with present ex

Felice Pisano

We consider a simple way for solving the flavor question by embedding the three-familiy Standard Model in a semisimple gauge group extending minimally the weak isospin factor. Quantum chiral anomalies between families of fermions cancel with a matching of the number of families and the number of color degrees of freedom. Our demonstration shows how the theor

Armelle Barelli, Jean Bellissard, Philippe Jacquod, Dima L. Shepelyansky

We study the effect of interparticle interaction $U$ on the spectrum of the Harper model and show that it leads to a pure-point component arising from the multifractal spectrum of non interacting problem. Our numerical studies allow to understand the global structure of the spectrum. Analytical approach developed permits to understand the origin of localized

D. L. Shepelyansky

Dynamics of two particles with short range repulsive or attractive interaction is studied numerically in the Harper model. It is shown that interaction leads to appearance of localized states and pure-point spectrum component in the case when noninteractive system is quasi-diffusive or ballistic. In the localized phase interaction gives only stronger localiz

Chee Kwan Gan, Jian-Sheng Wang

We obtain long series (28 terms or more) for the coverage (occupation fraction) $θ$, in powers of time $t$ for two models of random sequential adsorption with diffusional relaxation using an efficient algorithm developed by the authors. Three different kinds of analyses of the series are performed for a wide range of $γ$, the rate of diffusion of the adsorbe

B. L. Altshuler, Y. Gefen, A. Kamenev, L. S. Levitov

The problem of electron--electron lifetime in a quantum dot is studied beyond perturbation theory by mapping it onto the problem of localization in the Fock space. We identify two regimes, localized and delocalized, corresponding to quasiparticle spectral peaks of zero and finite width, respectively. In the localized regime, quasiparticle states are very clo

N. Bulut, D. J. Scalapino

An important question is if the gap in the high temperature cuprates has d_{x^2-y^2} symmetry, what does that tell us about the underlying interaction responsible for pairing. Here we explore this by determining how three different types of electron-phonon interactions affect the d_{x^2-y^2} pairing found within an RPA treatment of the 2D Hubbard model. Thes

S. Hanany, MAX collaboration, MAXIMA collaboration

We summarize the performance of the MAX experiment during its 5 years of operation and present a compilation of the results to date. We describe MAXIMA, a balloon borne experiment employing an array of detectors in the focal plane, that will provide sensitive measurements of the power spectrum between l~60 and l~650.

Misha Verbitsky

Let $M$ be a compact hyperkaehler manifold. The hyperkaehler structure equips $M$ with a set $R$ of complex structures parametrized by $CP^1$, called &#34;the set of induced complex structures&#34;. It was known previously that induced complex structures are non-algebraic, except may be a countable set. We prove that a countable set of induced complex struct

JM Figueroa-O&#39;Farrill

It was observed some time ago by Shatashvili and Vafa that superstring compactification on manifolds of exceptional holonomy gives rise to superconformal field theories with extended chiral algebras. In their paper, free field realisations are given of these extended superconformal algebras inspired by Joyce&#39;s constructions of such manifolds as desingula

David J. Fernandez C.

The exactly solvable eigenproblems in Schrödinger quantum mechanics typically involve the differential &#34;shift operators&#34;. In the standard supersymmetric (SUSY) case, the shift operator turns out to be of first order. In this work, I discuss a technique to generate exactly solvable eigenproblems by using second order shift operators. The links between

C. Klimcik, P. Severa

An abundance of the Poisson-Lie symmetries of the WZNW models is uncovered. They give rise, via the Poisson-Lie $T$-duality, to a rich structure of the dual pairs of $D$-branes configurations in group manifolds. The $D$-branes are characterized by their shapes and certain two-forms living on them. The WZNW path integral for the interacting $D$-branes diagram

Martin Beneke, Gerhard Buchalla, Isard Dunietz

We consider CP violating asymmetries that are induced by particle-antiparticle mixing in inclusive channels of neutral $B$ meson decay. Not only are the branching ratios sizable, at the 1% to 50% level, but some of those asymmetries are expected to be large because of substantial CKM phases. The inclusive sum partially dilutes the asymmetries, but the diluti

Roberto Iengo, Giancarlo Jug

We study the phenomenon of decay of a supercurrent in a superconducting thin film due to the spontaneous homogeneous nucleation of quantized vortex-antivortex pairs in the absence of an external magnetic field and in the presence of a periodic pinning potential. We describe the vortex nucleation by means of a Schwinger-type path-integral calculation includin

H. M. Cataldo, M. A. Despósito, E. S. Hernández, D. M. Jezek

We propose a Hamiltonian model that describes the interaction between a vortex line in superfluid $^{4}$He and the gas of elementary excitations. An equation of irreversible motion for the density operator of the vortex, regarded as a macroscopic quantum particle with a finite mass, is derived in the frame of Generalized Master Equations. This enables us to