May 1995 arXiv papers — page 11

V. John, G. Jungman, S. Vaidya

The role of edge states in phenomena like the quantum Hall effect is well known. In this paper we show how the choice of boundary conditions for a one-particle Schrödinger equation can give rise to states localized at the edge of the system. We consider both the example of a free particle and the more involved example of a particle in a magnetic field. In ea

Cumrun Vafa

By studying string loop corrections to superpotential of type II strings compactified on Calabi-Yau threefolds we find a quantum stringy test and a confirmation of a recent proposal of Strominger on the fate of the conifold singularity. We also propose a connection between the spectrum of Bogomolnyi saturated solitons and one-loop string partition function o

R. Tateo

The sine-Gordon Y-systems and those of the minimal $M_{p,q}+ϕ_{13}$ models are determined in a compact form and a correspondence between the rational numbers and a new infinite family of multi-parameter functional equations for the Rogers dilogarithm is pointed out. The relation between the TBA-duality and the massless RG fluxes in the minimal models recentl

Ranjan K. Ghosh, Sumathi Rao

We find that the energy spectra of four and five anyons in a harmonic potential exhibit some mirror symmetric (reflection symmetric about the semionic statistics point $θ=π/2$) features analogous to the mirror symmetry in the two and three anyon spectra. However, since the $\ell=0$ sector remains non-mirror symmetric, the fourth and fifth virial coeffients d

A. J. van der Sijs

Aspects of the monopole condensation picture of confinement are discussed. First, the nature of the monopole singularities in the abelian projection approach is analysed. Their apparent gauge dependence is shown to have a natural interpretation in terms of 't~Hooft-Polyakov-like monopoles in euclidean SU(2) gauge theory. Next, the results and predictions

Q-Han Park, H. J. Shin

The matrix sine-Gordon theory, a matrix generalization of the well-known sine-Gordon theory, is studied. In particular, the $A_{3}$-generalization where fields take value in $SU(2)$ describes integrable deformations of conformal field theory corresponding to the coset $SU(2) \times SU(2) /SU(2)$. Various classical aspects of the matrix sine-Gordon theory are

Jogesh C. Pati

A case is made for an alternative approach to unification that is based on a {\it purely gauge origin of the fundamental forces}, and is thus devoid of the Higgs-sector altogether. This approach seems to call for the ideas of local supersymmetry and preons. The advantage of this marriage of the ideas of local supersymmetry and preons, subject to two broad dy

Matthias Burkardt

Precise measurements of polarized electro-production and Drell-Yan in the deep inelastic limit will soon provide first information on the higher twist parton distributions $g_T(x)$ and $h_L(x)$. Sum rules for higher-twist structure functions are only valid provided the corresponding Compton amplitudes satisfy un-subtracted dispersion relations. Subtracted di

Bernd A. Kniehl, M. Spira

We present low-energy theorems for the calculation of loop amplitudes with external scalar or pseudoscalar Higgs bosons which are light compared to the loop particles. Starting from existing lowest-order versions of these theorems, we show how their applicability may be extended to the two--loop level. To illustrate the usefulness of these theorems, we discu

J. Bernabéu, G. A. González-Sprinberg, J. Vidal

The weak dipole moments of leptons and quarks, \ie those related to their $Z$--coupling, are reviewed. Standard Model predictions and experimental results may result in a stringent test for both their pointlike structure and also for the Standard Model. Special attention is devoted to the anomalous weak--magnetic dipole moment and to the $CP$--violating weak

G. Eilam, A. Ioannissian, R. R. Mendel

We demonstrate that the long distance contribution to $B^{\pm} \to ρ^{\pm} γ$ may have a large effect on the decay rate and through it on the CP violating partial rate asymmetry. The change in the asymmetry can be between a factor of 0.4 and 1.4 with respect to the effect of the short distance contribution alone, depending on the values of the CKM parameters

A. Patkós, P. Petreczky, J. Polonyi

Dimensional reduction of finite temperature quantum field theories can be improved with help of continous renormalisation group steps. The method is applied to the integration of the lowest non-static ($n=\pm 1$) modes of the finite temperature $Φ^4$-theory. A second, physically important application is the integration of the Debye-screened ${\bf A_0}(x)$ st

D. Boyanovsky, M. D'Attanasio, H. J. de Vega, R. Holman

We consider the non-equilibrium evolution of the inflaton field coupled to both lighter scalars and fermions. The dissipational dynamics of this field is studied and found to be quite different than that believed in inflationary models. In particular, the damping time scale for the expectation value of the zero momentum mode of the inflaton can be much short

Claude Amsler, Frank Close

We show that the newly discovered scalar meson $f_0(1500)$ at LEAR has properties compatible with the lightest scalar glueball predicted by lattice QCD and incompatible with a $\qqbar$ state. We suggest that decays of glueballs are into pairs of glueballs (including $η, η'$ or $(ππ)_S$) or by mixing with nearby $Q\bar{Q}$ states. The partial widths of $f

A. L. Provorov, I. M. Zheleznykh

The sensitivity of an ice radiowave detector to the anticipated high energy neutrino fluxes is calculated on the basis of a detailed threshold analysis and computation of the shower production rate. We show that diffuse neutrinos from Active Galactic Nuclei could be detectable in a radio detector of 1 sq.km area established in Central Antarctica.

M. L. Stong

The spectra of baryons containing two heavy quarks test the form of the $QQ$ potential through the spin-averaged masses and hyperfine splittings. The mass splittings in these spectra are calculated in a nonrelativistic potential model and the effects of varying the potential studied. The simple description in terms of light quark and pointlike diquark is not

Daniel M. Kaplan, Vassili Papavassiliou

After reviewing the motivation for high-statistics charm studies, we describe a fixed-target experiment capable of reconstructing $>10^8$ charm decays. Such an experiment can test the Standard Model and probe non-Standard physics through sensitive searches for such phenomena as D0 mixing, CP violation, and FCNC decays.

ZEUS Collaboration

Photoproduction at HERA is studied in $ep$ collisions, with the ZEUS detector, for $γp$ centre-of-mass energies ranging from 130-270 GeV. A sample of events with two high-$p_T$ jets ($p_T > 6$ GeV, $η<1.6$) and a third cluster in the approximate direction of the electron beam is isolated using a clustering algorithm. These events are mostly due to resolved p

L. J. Alty, A. Chamblin

We develop various topological notions on four-manifolds of Kleinian signature $(- - + +)$. In particular, we extend the concept of `Kleinian metric homotopy&#39; to non-orientable manifolds. We then derive the topological obstructions to pin-Klein cobordism, for all of the pin groups. Finally, we discuss various examples and applications which arise from th

A. Alastuey, P. J. Forrester

A systematic study of the properties of particle and charge correlation functions in the two-dimensional Coulomb gas confined to a one-dimensional domain is undertaken. Two versions of this system are considered: one in which the positive and negative charges are constrained to alternate in sign along the line, and the other where there is no charge ordering

A. Alastuey, P. J. Forrester

We consider the two-dimensional one-component plasma without a background and confined to a half plane near a metal wall. The particles are also subjected to an external potential acting perpendicular to the wall with an inverse power law Boltzmann factor. The model has a known solvable isotherm which exhibits a Kosterlitz-Thouless type transition from a con

Franco Nori, Roberto Merlin, Stephan Haas, Anders Sandvik

We calculate the Raman spectrum of the two-dimensional (2D) spin-1/2 Heisenberg antiferromagnet by exact diagonalization and quantum Monte Carlo techniques on clusters of up to 144 sites and, on a 16-site cluster, by considering the phonon-magnon interaction which leads to random fluctuations of the exchange integral. Results are in good agreement with exper

Serguei B. Isakov, Stefan Mashkevich, Stéphane Ouvry

We address the problem of multispecies anyons, i.e. particles of different species whose wave function is subject to anyonlike conditions. The cluster and virial coefficients are considered. Special attention is paid to the case of anyons in the lowest Landau level of a strong magnetic field, when it is possible (i) to prove microscopically the equation of s

John M. Golden, Bertrand I. Halperin

We study the relation between the barrier conductance and the Coulomb blockade peak splitting for two electrostatically equivalent dots connected by tunneling channels with bandwidths much larger than the dot charging energies. We note that this problem is equivalent to a well-known single-dot problem and present solutions for the relation between peak split

Thorsten Brants

A technique for reducing a tagset used for n-gram part-of-speech disambiguation is introduced and evaluated in an experiment. The technique ensures that all information that is provided by the original tagset can be restored from the reduced one. This is crucial, since we are interested in the linguistically motivated tags for part-of-speech disambiguation.

Robert Kasper, Bernd Kiefer, Klaus Netter, K. Vijay-Shanker

We present an implemented compilation algorithm that translates HPSG into lexicalized feature-based TAG, relating concepts of the two theories. While HPSG has a more elaborated principle-based theory of possible phrase structures, TAG provides the means to represent lexicalized structures more explicitly. Our objectives are met by giving clear definitions th

James Shaw

Aggregating different pieces of similar information is necessary to generate concise and easy to understand reports in technical domains. This paper presents a general algorithm that combines similar messages in order to generate one or more coherent sentences for them. The process is not as trivial as might be expected. Problems encountered are briefly desc

Vladimir Pericliev, Alexander Grigorov

A logic formalism is presented which increases the expressive power of the ID/LP format of GPSG by enlarging the inventory of ordering relations and extending the domain of their application to non-siblings. This allows a concise, modular and declarative statement of intricate word order regularities.

Veronica Dahl, Paul Tarau, Lidia Moreno, Manolo Palomar

In previous work we studied a new type of DCGs, Datalog grammars, which are inspired on database theory. Their efficiency was shown to be better than that of their DCG counterparts under (terminating) OLDT-resolution. In this article we motivate a variant of Datalog grammars which allows us a meta-grammatical treatment of coordination. This treatment improve

G. Filatrella, K. Wiesenfeld

We study analytically the effect of a constant magnetic field on the dynamics of a two dimensional Josephson array. The magnetic field induces spatially dependent states and coupling between rows, even in the absence of an external load. Numerical simulations support these conclusions.

Tom Broadhurst, Joseph Lehar

We show that the high redshift IRAS source F10214 is highly magnified by the gravitational field of an intervening elliptical galaxy, accounting for its many anomalous properties. Detailed radio and near-IR images identify the IRAS source with a symmetric arc, centered on a red object, or lensing galaxy. To explain the observed structures, the center of the

George F. Smoot

The properties of high latitude dust are of great interest to extragalactic astronomers and cosmologists. It is proposed here that essentially all high Galactic latitude interstellar dust is at a typical temperature of about 20~K (i.e. it is warm dust) and that if any cold high latitude interstellar dust exists, its emission at mm-wavelengths is less than 5\

Sidney van den Bergh

The large-scale prints in The Carnegie Atlas of Galaxies have been used to formulate a classification scheme for the central regions of late-type galaxies. Systems that exhibit small bright central bulges or disks (type CB) are found to be of earlier Hubble type and of higher luminosity than galaxies that do not contain nuclei (type NN). Galaxies containing

Tom Broadhurst

Lensing in the context of rich clusters is normally quantified from small image distortions, yielding a relative mass distribution in the limit of weak lensing. Here we show the magnification effect of lensing can also be mapped over a cluster, resulting in absolute mass determinations for the weak limit. Furthermore, given both magnification and distortion

Mordehai Milgrom, Vladimir Usov

We point out that each of the error boxes of the two highest-energy cosmic-ray shower events known, overlaps with that of a strong gamma-ray burst (GRB). The GRBs precede the cosmic rays by 5.5, and 11 months respectively. In one case the strongest known cosmic ray is paired with the strongest gamma-ray burst in the BATSE catalogue. The probability of this t

Brian J. Soden, Francis P. Bretherton

This study illustrates the application of a random strong line (RSL) model of radiative transfer to the interpretation of satellite observations of the upwelling radiation in the 6.3 micron water vapor absorption band. The model, based upon an assemblage of randomly overlapped, strongly absorbing, pressure broadened lines, is compared to detailed radiative t

Ionuţ Ciocan-Fontanine

We describe a construction of Gromov-Witten invariants for flag varieties and use it to give a presentation for the quantum cohomology ring, by extending the ideas used by Bertram in the case of Grassmannians. This provides a proof for the conjecture of Givental and Kim in [GK].

J. A. de Azcarraga, J. C. Perez Bueno

The deformations of the Galilei algebra and their associated noncommutative Newtonian spacetimes are investigated. This is done by analyzing the possible nonrelativistic limits of an eleven generator (pseudo)extended \kap-Poincaré algebra $\tilde{\cal P}_κ$ and their implications for the existence of a first order differential calculus. The additional one-fo

Robert M. Losee

The grammars of natural languages may be learned by using genetic algorithms that reproduce and mutate grammatical rules and part-of-speech tags, improving the quality of later generations of grammatical components. Syntactic rules are randomly generated and then evolve; those rules resulting in improved parsing and occasionally improved retrieval and filter

C. D. Fosco, S. Randjbar-Daemi

Using the overlap formulation, we calculate the fermionic determinant on the lattice for chiral fermions with twisted boundary conditions in two dimensions. When the lattice spacing tends to zero we recover the results of the usual string-theory continuum calculations.

A. Yu. Alekseev, P. Schaller, T. Strobl

We consider the topological gauged WZW model in the generalized momentum representation. The chiral field $g$ is interpreted as a counterpart of the electric field $E$ of conventional gauge theories. The gauge dependence of wave functionals $Ψ(g)$ is governed by a new gauge cocycle $ϕ_{GWZW}$. We evaluate this cocycle explicitly using the machinery of Poisso

Emilio Torrente-Lujan

Exact analytical expressions in terms of generalized confluent hypergeometric functions for the transition amplitudes of neutrino oscillations in presence of matter are computed for an arbitrary number of species. The density of matter is assumed to be exponentially decaying. The results can be used for the description of matter-induced neutrino oscillations

Charilaos Aneziris

In a previous paper (q-alg/9501022) we suggested some algorithms that could be useful in solving the problem of knot classification. Here we continue this discussion by answering questions raised in that paper and by commenting on practical aspects related to running these algorithms as computer programs. Further on, we reach a solution by improving on the e

Martin Markl, Steve Shnider

In our paper [Markl, Shnider: Drinfel&#39;d Algebra Deformations and the Associahedra, IMRN 1994, no. 4, 169-176] we announced a construction of a cohomology controlling deformations of quasi-coassociative (or Drinfel&#39;d) bialgebras. The full version of the paper will appear as [Markl, Shnider: Drinfel&#39;d Algebra Deformations, Homotopy Comodules and th

Winfried Pfister

Starting from a nonlinear isospinor-spinor field equation, generalized three-particle Bargmann-Wigner equations are derived. In the strong-coupling limit, a special class of spin 1/2 bound-states are calculated. These solutions which are antisymmetric with respect to all indices, have mixed symmetries in isospin-superspin space and in spin orbit space. As a

Nelson R. F. Braga, Sergio M. de Souza

A superspace formulation for the Batalin Vilkovisky formalism (also called field-antifield quantization ) with extended BRST invariance (BRST and anti-BRST invariance ) for gauge theories with closed algebra is presented. In contrast to a recent formulation, where only BRST invariance holds off shell, two collective sets of fields are introduced and an off s

Mark Burgess

A gauge invariant quantum field theory with a spacetime dependent Chern-Simons coefficient is studied. Using a constraint formalism together with the Schwinger action principle it is shown that non-zero gradients in the coefficient induce magnetic-moment corrections to the Hall current and transform vortex singularities into non-local objects. The fundamenta

C. Quesne

It is shown that from some solutions of generalized Knizhnik-Zamolodchikov equations one can construct eigenfunctions of the Calogero-Sutherland-Moser Hamiltonians with exchange terms, which are characterized by any given permutational symmetry under particle exchange. This generalizes some results previously derived by Matsuo and Cherednik for the ordinary

Javier P. Muniain, Dardo D. Piriz

Anomalous contributions to the energy-momentum commutators are calculated for even dimensions, by using a non-perturbative approach that combines operator product expansion and Bjorken-Johnson-Low limit techniques. We first study the two dimensional case and give the covariant expression for the commutators. The expression in terms of light-cone coordinates

A. Nersessian, P. H. Damgaard

We give a simple geometrical picture of the basic structures of the covariant $Sp(2)$ symmetric quantization formalism -- triplectic quantization -- recently suggested by Batalin, Marnelius and Semikhatov. In particular, we show that the appearance of an even Poisson bracket is not a particular property of triplectic quantization. Rather, any solution of the

Silvio Pallua, Predrag Prester

We consider the Hamiltonian of the closed $SU(2)_{q}$ invariant chain. We project a particular class of statistical models belonging to the unitary minimal series. A particular model corresponds to a particular value of the coupling constant. The operator content is derived. This class of models has charge-dependent boundary conditions. In simple cases (Isin

Zhan-Ning Hu

In this paper, a three-dimensional vertex model is obtained. It is a duality of the three-dimensional integrable lattice model with $N$ states proposed by Boos, Mangazeev, Sergeev and Stroganov. The Boltzmann weight of the model is dependent on four spin variables, which are the linear combinations of the spins on the corner sites of the cube, and obeys the

K. Intriligator, P. Pouliot

We study $N=1$ supersymmetric $SP(N_c)$ gauge theories with $N_f$ flavors of quarks in the fundamental representation. Depending on $N_f$ and $N_c$, we find exact, dynamically generated superpotentials, smooth quantum moduli spaces of vacua, quantum moduli spaces of vacua with additional massless composites at strong coupling, confinement without chiral symm

Tamás G. Kovács, E. T. Tomboulis, Zsolt Schram

We study two-dimensional U($N$) and SU($N$) gauge theories with a topological term on arbitrary surfaces. Starting from a lattice formulation we derive the continuum limit of the action which turns out to be a generalisation of the heat kernel in the presence of a topological term. In the continuum limit we can reconstruct the topological information encoded

G. Krein, D. P. Menezes, M. Nielsen, M. B. Pinto

The possibility of using the optimized $δ$ expansion for studying medium effects on hadronic properties in quark or nuclear matter is investigated. The $δ$ expansion is employed to study density effects with two commonly used models in hadron and nuclear physics, the Nambu--Jona-Lasinio model for the dynamical chiral symmetry breaking and the Walecka model f

M. W. Beinker, B. C. Metsch, H. R. Petry

We consider the existence of bound systems consisting of two quarks and two antiquarks ($q^2\bar q^2$) within the framework of a constituent quark model. The underlying quark dynamics is described by a linear confinement potential and an effective $q^2\bar q^2$ interaction which has its origin in instanton effects of QCD. We calculate the spectra and examine

Edi Halyo

We investigate the effects of hidden matter condensation on supersymmetry breaking in supergravity models derived from free fermionic strings. We find that the minimum of the effective potential in the modulus direction depends strongly on only one parameter which is fixed by the hidden sector. For nonpositive values of the parameter the potential is unstabl

O. Benhar, S. Liuti

We propose an interpretation of the $ξ$-scaling behavior of nuclear structure functions observed at Bjorken $x>1$ and $Q^2 \lesssim 4 \, {\rm (GeV/c)^2}$. We show that at $ξ\gtrsim 1$, $ξ$-scaling might arise accidentally because of the approximate cancellation of two different $Q^2$-dependent effects, namely Final State Interactions and the effects implicit

R. Casalbuoni, P. Chiappetta, D. Dominici, A. Fiandrino

We study top production at Tevatron collider in the extended BESS model, which is an effective lagrangian parametrization of a dynamical symmetry breaking of the electroweak symmetry. The existence of a colored octet of gauge vector bosons can increase top production at a rate still consistent with recent experimental data and lead to distorsions in the tran

Michael H. Seymour

We discuss the lineshape of a heavy Higgs boson, and the behaviour well above resonance. Previous studies concluded that the energy-dependent Higgs width should be used in the resonance region, but must not be used well away from it. We derive the full result and show that it smoothly extrapolates these limits. It is extremely simple, and would be straightfo

Kari Enqvist, Jukka Maalampi, V. B. Semikoz

We discuss the excitation of sterile neutrinos in the early universe using general quantum kinetic equations, which also incorporate a possible primordial magnetic field $B$. We find a new contribution to the excitation propability, which has its origin in the shrinkage of the spin vector. In the absence of $B$ nucleosynthesis implies the constraint $\mid Δm

Kensuke Kusaka, Anthony G. Williams

The Bethe-Salpeter (BS) equation for scalar-scalar bound states in scalar theories without derivative coupling is formulated and solved in Minkowski space. This is achieved using the perturbation theory integral representation (PTIR), which allows these amplitudes to be expressed as integrals over weight functions and known singularity structures and hence a

G. L. Kane, Robin G. Stuart, James D. Wells

We find that re-analyzing the LEP/SLC data with light superpartners and low $α_s(\mz^2)\simeq 0.112$ yields a better fit to the data than the Standard Model, giving a satisfactory description of the $R_b$ measurement, and a better fit to $A_{LR}$. A large body of low energy ($q^2 \ll \mz^2$) data and analyses provide compelling evidence for $α_s(\mz^2)\simeq

Wolfgang Beirl, Bernd A. Berg

A hybrid model which allows to interpolate between the (original) Regge approach and dynamical triangulations is introduced. The gained flexibility in the measure is exploited to study dynamical triangulation in a fixed geometry. Our numerical results support KPZ exponents. A critical assessment concerning the apparent lack of gravitational effects in two di

Antonio Campos, Rosario Martín, Enric Verdaguer

A simple model for the formation of a straight cosmic string, wiggly or unperturbed is considered. The gravitational field of such string is computed in the linear approximation. The vacuum expectation value of the stress tensor of a massless scalar quantum field coupled to the string gravitational field is computed to the one loop order. Finally, the back-r

P. V. Moniz

The general theory of N=1 supergravity with supermatter is applied to a Bianchi type IX diagonal model. The supermatter is constituted by a complex scalar field and its spin-$1\over 2$ fermionic partners. The Lorentz invariant Ansatz for the wave function of the universe, $Ψ$, is taken to be as simple as possible in order to obtain {\it new} solutions. The w

Arnold Sikkema, Ian Affleck

The phase diagram of a one-dimensional tight-binding model with a pair-hopping term (amplitude V) has been the subject of some controvery. Using two-loop renormalization group equations and the density matrix renormalization group with lengths L<=60, we argue that no spin-gap transition occurs at half-filling for positive V, contrary to recent claims. Howeve

Branko P. Stojkovic, David Pines

The temperature dependence of the normal state Hall effect and magnetoresistance in YBa$_2$Cu$_3$O$_7$ is investigated using the Nearly Antiferromagnetic Fermi Liquid description of planar quasiparticles. We find that highly anisotropic scattering at different regions of the Fermi surface gives rise to the measured anomalous temperature dependence of the res

D. Poilblanc

The phase diagram of the planar t--J model at small hole doping is investigated by finite size scaling of exact diagonalisation data of NXN clusters (up to 26). Hole-droplet binding energies, compressibility and static spin and charge correlations are calculated. Short range antiferromagnetic correlations can produce attractive forces between holes leading t

Luca Peliti

The concept of fitness is introduced, and a simple derivation of the Fundamental Theorem of Natural Selection (which states that the average fitness of a population increases if its variance is nonzero) is given. After a short discussion of the adaptative walk model, a short review is given of the quasispecies approach to molecular evolution and to the error

Bill Keller

Evans and Gazdar introduced DATR as a simple, non-monotonic language for representing natural language lexicons. Although a number of implementations of DATR exist, the full language has until now lacked an explicit, declarative semantics. This paper rectifies the situation by providing a mathematical semantics for DATR. We present a view of DATR as a langua

Thilo Goetz, Walt Detmar Meurers

We present a new approach to HPSG processing: compiling HPSG grammars expressed as type constraints into definite clause programs. This provides a clear and computationally useful correspondence between linguistic theories and their implementation. The compiler performs off-line constraint inheritance and code optimization. As a result, we are able to effici

A. Torcini, P. Grassberger, A. Politi

A strong analogy is found between the evolution of localized disturbances in extended chaotic systems and the propagation of fronts separating different phases. A condition for the evolution to be controlled by nonlinear mechanisms is derived on the basis of this relationship. An approximate expression for the nonlinear velocity is also determined by extendi

D. M. Christodoulou, D. Kazanas, I. Shlosman, J. E. Tohline

In Papers I and II, we have used a free-energy minimization approach that stems from the Landau-Ginzburg theory of phase transitions to describe in simple and clear physical terms the secular and dynamical instabilities as well as the bifurcations along equilibrium sequences of rotating, self-gravitating fluid systems. Here we investigate the secular and dyn

N. Benitez, E. Martinez-Gonzalez

We have found a statistically significant (99.1 \%) excess of red ($O-E>2$) galaxies with photographic magnitudes $E<19.5$, $O< 21$ taken from the APM Sky Catalogue around $z \sim 1$ radiosources from the 1Jy catalogue. The amplitude, scale and dependence on galaxy colours of the observed overdensity are consistent with its being a result of the magnificatio

Wolfram Freudling, Luiz N. Da Costa, Gary Wegner, Riccardo Giovanelli

Maps of the peculiar velocity field derived from distance relations are affected by Malmquist type bias and selection effects. Because of the large number of interdependent effects, they are in most cases difficult to treat analytically. Monte Carlo simulations are used to understand and evaluate these effects. In these simulations the ``true'' spatial distr

Varun Sahni, Peter Coles

We discuss various analytical approximation methods for following the evolution of cosmological density perturbations into the strong (i.e. nonlinear) clustering regime. These methods can be classified into five types: (i) simple extrapolations from linear theory, such as the high--peak model and the lognormal model; (ii) {\em dynamical} approximations, incl

F. E. Nakamura, M. Hattori, S. Mineshige

Recent X-ray observations have established that collisions between subclusters of galaxies are rather common phenomena. Prompted by such observations, we have performed N-body simulations of two equal-mass subclusters of galaxies, which are going to merge. We first have confirmed that only a part of kinetic energy associated with the relative motion of two s

Rob P. Olling

I present a new method of deriving the shape of the dark matter (DM) halos of spiral galaxies. The method relies on the comparison of model predictions with high spectral and spatial resolution HI observations of the gas layer. The potential arising from the {\em total} mass distribution of the galaxy is used in the calculation of the vertical distribution o

Frank Sottile

We establish the formula for multiplication by the class of a special Schubert variety in the integral cohomology ring of the flag manifold. This formula also describes the multiplication of a Schubert polynomial by either an elementary symmetric polynomial or a complete homogeneous symmetric polynomial. Thus, we generalize the classical Pieri&#39;s rule for

Csaba Balazs, Jianwei Qiu, C. --P. Yuan

We study the distributions of leptons from the decay of electroweak vector bosons produced in hadron collisions. The effects of the initial state multiple soft-gluon emission, using the Collins--Soper resummation formalism, are included. The resummed results are compared with the next-to-leading-order results for the distributions of the transverse momentum,

Y. Koide, H. Fusaoka

We investigate the implications of a seesaw type mass matrix, i.e., $M_f\simeq m_L M_F^{-1} m_R$, for quarks and leptons $f$ under the assumption that the matrices $m_L$ and $m_R$ are common to all flavors (up-/down- and quark-/lepton- sectors) and the matrices $M_F$ characterizing the heavy fermion sectors have the form [(unit matrix) + $b_f$ (a democratic

P. Ao

Based on the vortex dynamics with the Magnus force and a two-fluid model we have derived a set of explicit expressions between the Nernst and Seebeck coefficients, and the Hall and longitudinal resistivities in the linear response regime of the mixed state of superconductors. Effects of vortex pinning are included. The expressions are found to be in agreemen

Sayan Kar

Specific examples of the generalized Raychaudhuri Equations for the evolution of deformations along families of $D$ dimensional surfaces embedded in a background $N$ dimensional spacetime are discussed. These include string worldsheets embedded in four dimensional spacetimes and two dimensional timelike hypersurfaces in a three dimensional curved background.

E. V. Damaskinsky, P. P. Kulish, M. A. Sokolov

The Gauss decompositions of the quantum groups, related to classical Lie groups and supergroups are considered by the elementary algebraic and $R$-matrix methods. The commutation relations between new basis generators (which are introduced by the decomposition) are described in some details. It is shown that the reduction of the independent generator number

L. N. Kantorovich, J. M. Holender, M. J. Gillan

Ab initio calculations based on the density-functional pseudopotential approach have been used to study the fully relaxed structure, the electron distribution and the electronic density of states of (001) terraces, steps, corners and reverse corners, and of F-centers at these surface features on MgO. The calculations confirm earlier predictions of the relaxe

D. Kutasov, A. Schwimmer

We discuss non-abelian $SU(N_c)$ gauge theory coupled to an adjoint chiral superfield $X$, and a number of fundamental chiral superfields $Q^i$. Using duality, we show that turning on a superpotential $W(X)=\Tr\sum_{l=1}^k g_l X^{l+1}$ leads to non-trivial long distance dynamics, a large number of multicritical IR fixed points and vacua, connected to each ot

Tim R. Morris

We show that if actions more general than the usual simple plaquette action ($\sim F_{μν}^2$) are considered, then compact $U(1)$ {\sl pure} gauge theory in three Euclidean dimensions can have two phases. Both phases are confining phases, however in one phase the monopole condensate spontaneously `magnetizes&#39;. For a certain range of parameters the phase

K. A. Milton

We complete the formulation of the equations of motion of a non-Abelian gauge field coupled to fermions on a finite-element lattice in four space-time dimensions. This is accomplished by a straightforward iterative approach, in which successive interaction terms are added to the Dirac and Yang-Mills equations of motion, and to the field strength, in order to

M. Yu. Kuchiev

A gauge theory model in which there exists a specific interaction between instantons is considered. An effective action describing this interaction possesses a minimum when the instantons have identical orientation. The considered interaction might provide a phase transition into the state where instantons have a preferred orientation. This phase of the gaug

Masayasu Harada, Yuhsuke Yoshida

We study a method for solving the homogeneous Bethe-Salpeter equation. By introducing a `fictitious&#39; eigenvalue $λ$ the homogeneous Bethe-Salpeter equation is interpreted as a linear eigenvalue equation, where the bound state mass is treated as an input parameter. Using the improved ladder approximation with the constant fermion mass, we extensively stud

M. G. Olsson, S. Veseli, K. Williams

Quark-antiquark bound states are examined in the long-range strong-coupling limit with the minimal area law of lattice gauge theory assumed as input. Matrix element relations are established which in the effective theory obtain dynamical equations equivalent to a formulation of the flux-tube model.

J. L. Goity, M. J. Musolf

The strange-quark vector current $ρ$-to-$π$ meson transition form factor is computed at one-loop order using strange meson intermediate states. A comparison is made with a $ϕ$-meson dominance model estimate. We find that one-loop contributions are comparable in magnitude to those predicted by $ϕ$-meson dominance. It is possible that the one-loop contribution

R. Sekhar Chivukula

I describe theories of a strongly-interacting electroweak symmetry breaking sector and discuss the expected size of anomalous weak-boson couplings in these models.

Carl R. Schmidt

We study the effects of QCD corrections to the process $e^+e^-\rightarrow t\bar t+X\rightarrow b\ell^+ν\bar b\ell^-\bar ν+X$ above threshold. We show how to treat consistently to ${\cal O}(α_s)$ the gluon radiation in both the production and the decay of the top quarks, while maintaining all angular correlations in the event. At this order there is an ambigu

K. Scharnhorst

Some time ago Salmhofer demonstrated the equivalence of the strong coupling lattice Schwinger model with Wilson fermions to a certain 8-vertex model which can be understood as a self-avoiding loop model on the square lattice with bending rigidity $η= 1/2$ and monomer weight $z = (2κ)^{-2}$. The present paper applies two approximate analytical methods to the

W. W. Cohen

In a companion paper it was shown that the class of constant-depth determinate k-ary recursive clauses is efficiently learnable. In this paper we present negative results showing that any natural generalization of this class is hard to learn in Valiant&#39;s model of pac-learnability. In particular, we show that the following program classes are cryptographi

W. W. Cohen

We present algorithms that learn certain classes of function-free recursive logic programs in polynomial time from equivalence queries. In particular, we show that a single k-ary recursive constant-depth determinate clause is learnable. Two-clause programs consisting of one learnable recursive clause and one constant-depth determinate non-recursive clause ar

S. J. Russell, D. Subramanian

Since its inception, artificial intelligence has relied upon a theoretical foundation centered around perfect rationality as the desired property of intelligent systems. We argue, as others have done, that this foundation is inadequate because it imposes fundamentally unsatisfiable requirements. As a result, there has arisen a wide gap between theory and pra

A. Schaerf, Y. Shoham, M. Tennenholtz

We study the process of multi-agent reinforcement learning in the context of load balancing in a distributed system, without use of either central coordination or explicit communication. We first define a precise framework in which to study adaptive load balancing, important features of which are its stochastic nature and the purely local information availab