September 1995 arXiv papers — page 9

Xiao-Song Lin, Zhenghan Wang

An attempt is made to conceptualize the derivation as well as to facilitate the computation of Ohtsuki's rational invariants $λ_n$ of integral homology 3-spheres extracted from Reshetikhin-Turaev SU(2) quantum invariants. Several interesting consequences will follow from our computation of $λ_2$. One of them says that $λ_2$ is always an integer divisible

R. C. Brower, T. Ivanenko, A. R. Levi, K. N. Orginos

In Hybrid Monte Carlo simulations for full QCD, the gauge fields evolve smoothly as a function of Molecular Dynamics time. Here we investigate improved methods of estimating the trial or starting solutions for the Dirac matrix inversion as superpositions of a chronological sequence of solutions in the recent past. By taking as the trial solution the vector w

M. V. Polyakov, V. V. Vereshagin

Parameters of the effective chiral lagrangian (EChL) of orders $O(p^4)$ and $O(p^6)$ are extracted from low--energy behaviour of dual resonance models for $ ππ$ and $πK$ scattering amplitudes. Dual resonance models are considered to be good candidates for the resonance spectrum and for hadronic scattering amplitudes in the large $N_c$ limit of QCD. We discus

Alexander Fel'shtyn, Richard Hill

In this paper we prove the trace formulas for the Reidemeister numbers of group endomorphisms in the following cases:the group is finitely generated and an endomorphism is eventually commutative; the group is finite ; the group is a direct sum of a finite group and a finitely generated free abelian group; the group is finitely generated, nilpotent and torsio

Stefan Berceanu

Different topics on the differential geometry of the complex Grassmann manifold are surveyed in relation to the coherent states. A calculation of the tangent conjugate locus and conjugate locus in the complex Grassmann manifold is presented. The proofs use the Jordan's stationary angles. Also various formulas for the distance on the complex Grassmann man

A. Ritz, G. C. Joshi

A mapping between the operators of the bosonic oscillator and the Lorentz rotation and boost generators is presented. The analog of this map in the $q$-deformed regime is then applied to $q$-deformed bosonic oscillators to generate a $q$-deformed Lorentz algebra, via an inverse of the standard chiral decomposition. A fundamental representation, and the co-al

Efstratia Kalfagianni, Xiao-Song Lin

We construct a polynomial invariant, for links in a Seifert fibered or atoroidal rational homology 3-sphere, which generalizes the 2-variable Jones polynomial (HOMFLY). As a consequence, we show that the dual of the HOMFLY skein module of a homotopy 3-sphere is isomorpic to that of the genuine 3-sphere .

G. Bohm, K. Szlachanyi

By weakening the counit and antipode axioms of a C*-Hopf algebra and allowing for the coassociative coproduct to be non-unital we obtain a quantum group, that we call a weak C*-Hopf algebra, which is sufficiently general to describe the symmetries of essentially arbitrary fusion rules. This amounts to generalizing the Baaj-Skandalis multiplicative unitaries

P. J. Ellis, S. B. Parendo, M. Prakash

We have examined the contribution of the filled negative energy sea of hyperons to the energy/particle in nuclear matter at the one and two loop levels. While this has the potential to be significant, we find a strong cancellation between the one and two loop contributions for our chosen parameters so that hyperon effects can be justifiably neglected.

R. Bijker, A. Leviatan

We study the electromagnetic form factors of the nucleon in a collective model of baryons. In an algebraic approach to hadron structure, we derive closed expressions for both elastic and transition form factors, and consequently for the helicity amplitudes that can be measured in electro- and photoproduction.

A. A. Tseytlin

We suggest that for singular rotationally invariant closed string backgrounds which need sources for their support at the origin (in particular, for special plane waves and fundamental strings) certain `trivial' \a'-corrections (which are usually ignored since in the absence of sources they can be eliminated by a field redefinition) may play an impor

Paul Watts

General expressions for the anomalies appearing in pure W_3 gravity are found by requiring that they satisfy a modified version of the Wess-Zumino consistency conditions in which the Ward identities are treated as nonvanishing quantities.

Elias Kiritsis, Costas Kounnas

We construct groundstates of the string with non-zero mass gap and non-trivial chromo-magnetic fields as well as curvature. The exact spectrum as function of the chromo-magnetic fields and curvature is derived. We examine the behavior of the spectrum, and find that there is a maximal value for the magnetic field $H_{\rm max}\sim M_{\rm Plank}^2$. At this val

Gottfried Curio

The evidence for string/string-duality can be extended from the matching of the vector couplings to gravitational couplings. In this note this is shown in the rank three example, the closest stringy analog of the Seiberg/Witten-setup, which is related to the Calabi-Yau $WP^4_{1,1,2,2,6}(12)$. I provide an exact analytical verification of a relation checked b

Ayse Humeyra Bilge, Tekin Dereli, Sahin Kocak

The geometry of self-dual 2-forms in eight dimensions is studied. These 2-forms determine an $n^2-n+1$ dimensional manifold ${\cal S}_{2n}$. We prove that for add $n$, it has only one dimensionallinear subspaces. In eight dimensions, the self-dual forms of Corrigan et al constitue a seven dimensional linear subspace of ${\cal S}_8$, among many other intersti

E. H. Saidi

We introduce the concept of conformal spin gradation of the untwisted affine Lie superalgebra $\hat A(n-1| n-1)^{(1)}$ to study the $W\hat A (n-1| n-1)^{(1)}$ Miura transformation. We show that the essential of $\hat A(n-1| n-1)^{(1)}$ may be read from the conformal spin gradation of the canonical vector basis of the $SL(n| n)$ vector representation space $V

Atsuo Kuniba, Shuichi Nakamura, Ryogo Hirota

We consider a class of 2 dimensional Toda equations on discrete space-time. It has arisen as functional relations in commuting family of transfer matrices in solvable lattice models associated with any classical simple Lie algebra $X_r$. For $X_r = B_r, C_r$ and $D_r$, we present the solution in terms of Pfaffians and determinants. They may be viewed as Yang

G. V. Grigoryan, R. P. Grigoryan

The problem of the passage of the neutral massless particle with anomalous magnetic moment through the external electromagnetic field is considered both in pseudoclassical and quantum mechanics. The quantum description uses the hamiltonian in the Foldy--Wouthuysen representation, obtained from the pseudoclassical hamiltonian of the massive charged particle w

O. J. P. Eboli, E. M. Gregores, J. C. Montero, S. F. Novaes

We analyze the capability of the next generation of linear electron--positron colliders to unravel the spin and couplings of excited leptons predicted by composite models. Assuming that these machines will be able to operate both in the $e^+e^-$ and $e^-γ$ modes, we study the effects of the excited electrons of spin $\frac{1}{2}$ and $\frac{3}{2}$ in the rea

R. Kuchimanchi, R. N. Mohapatra

We show that in automatically R-conserving minimal SUSY left-right symmetric models there is a theoretical upper limit on the mass of the right-handed $W_R$ boson given by $M_{W_R}\leq g M_{SUSY}/f$, where $M_{SUSY}$ is the scale of supersymmetry breaking, g is the weak gauge coupling and $f$ is the Yukawa coupling responsible for generating the right-handed

E. Akhmedov, M. Lindner, E. Schnapka, J. W. F. Valle

We study a left--right symmetric model which contains only elementary gauge boson and fermion fields and no scalars. The phenomenologically required symmetry breaking emerges dynamically leading to a composite Higgs sector with a renormalizable effective Lagrangian. We discuss the pattern of symmetry breaking and phenomenological consequences of this scenari

V. B. Semikoz, S. Pastor, J. W. F. Valle

We consider the conversions of active to sterile Majorana neutrinos $ν_{a}$ and $ν_{s}$, due to neutrino transition magnetic moments in the presence of random magnetic fields (r.m.f.) generated at the electroweak phase transition. From a simple Schrödinger-type evolution equation, we derive a stringent constraint on the corresponding transition magnetic mome

A. Pich

$τ$ decays provide a powerful tool to test the structure of the weak currents and the universality of their couplings to the $W$ boson. The constraints implied by present data and the possible improvements at the $τ$-charm Factory are analyzed.

A. Riotto, I. Vilja

Nonequilibrium phenomena of the phase transitions are studied. It is shown that due to finite relaxation time of the particle distributions, the use of scalar background dependent distribution functions is inconsistent.This observation may change the picture of rapid processes during the electroweak phase transition, like subcritical bubble formation and pro

Frank Close

This talk summarises the discussions during the conference on the spin structure of the nucleon held at Erice; July 1995. The summary focuses on where we have come, where we are now, and the emerging questions that direct where we go next in the quest to understand the nucleon spin.

Lee Lin

Numerical simulations are performed on different lattice sizes of chiral U(1) and SU(2) scalar-fermion models with explicit mirror pairs of fermions in the broken symmetry phase. Relevance of these models to the electroweak theory is discussed. Shift symmetry of the action is exploited to decouple the unwanted mirror-fermion. Upper and lower bounds on the re

A. Galli

We generalize the hyper-systolic algorithm proposed in [1] for abstract data structures on massive parallel computers with $n_p$ processors. For a problem of size $V$ the communication complexity of the hyper-systolic algorithm is proportional to $\sqrt{n_p}V$, to be compared with $n_pV$ for the systolic case. The implementation technique is explained in det

Elias Kiritsis, Costas Kounnas

String theory provides the only consistent framework so far that unifies all interactions including gravity. We discuss gravity and cosmology in string theory. Conventional notions from general relativity like geometry, topology etc. are well defined only as low energy approximations in string theory. At small distances physics deviates from the field theore

J. Pérez-Mercader, T. Goldman, D. Hochberg, R. Laflamme

The observable Universe is described by a collection of equal mass galaxies linked into a common unit by their mutual gravitational interaction. The partition function of this system is cast in terms of Ising model spin variables and maps exactly onto a three-dimensional stochastic scalar classical field theory. The full machinery of the renormalization grou

M. J. Graf, S. -K. Yip, J. A. Sauls, D. Rainer

We use the quasiclassical theory of superconductivity to calculate the electronic contribution to the thermal conductivity. The theory is formulated for low temperatures when heat transport is limited by electron scattering from random defects and for superconductors with nodes in the order parameter. We show that certain eigenvalues of the thermal conductiv

M. R. Norman, P. J. Hirschfeld

Recent thermal conductivity data on the heavy fermion superconductor $UPt_3$ have been interpreted as offering support for an $E_{2u}$ model of the order parameter as opposed to an $E_{1g}$ model. In this paper, we analyze this issue from a theoretical standpoint including the detailed effects of Fermi surface and gap anisotropy. Our conclusion is that altho

O. K. Andersen, A. I. Liechtenstein, O. Jepsen, F. Paulsen

We describe the LDA bandstructure of YBa_2Cu_3O_7 in the 2 eV range from the Fermi energy using orbital projections and compare with YBa_2Cu_4O_8. Then, the high-energy and chain-related degrees of freedom are integrated out and we arrive at two, nearest-neighbor, orthogonal, two-center, 8-band Hamiltonians, the even and odd bands of the bi-layer. Of the 8 o

Martin T. Barlow, Kumiko Hattori, Tetsuya Hattori, Hiroshi Watanabe

We report a new type of restoration of macroscopic isotropy (homogenization) in fractals with microscopic anisotropy. The phenomenon is observed in various physical setups, including diffusions, random walks, resistor networks, and Gaussian field theories. The mechanism is unique in that it is absent in spaces with translational invariance, while universal i

S. A. van Langen, P. W. Brouwer, C. W. J. Beenakker

A non-perturbative random-matrix theory is applied to the transmission of a monochromatic scalar wave through a disordered waveguide. The probability distributions of the transmittances T_{mn} and T_n=\sum_m T_{mn} of an incident mode n are calculated in the thick-waveguide limit, for broken time-reversal symmetry. A crossover occurs from Rayleigh or Gaussia

Scott Grossman

We solve the nonlocal convection equations. The solutions for four model problems are compared with results of GSPH simulations. In each case we test two closure schemes: 1) where third moments are defined by the diffusion approximation; and 2) where the full third moment equations are used and fourth moments are defined by a modified form of the quasi-norma

Capp Yess, Sergei F. Shandarin

Using percolation statistics we, for the first time, demonstrate the universal character of a network pattern in the real space, mass distributions resulting from nonlinear gravitational instability of initial Gaussian fluctuations. Percolation analysis of five stages of the nonlinear evolution of five power law models reveals that all models show a shift to

W. Brandner, J. Bouvier, E. K. Grebel, E. Tessier

Using adaptive optics at the ESO 3.6m telescope, we obtained diffraction limited JHK-images of the region around the Herbig AeBe star NX Pup. We clearly resolved the close companion (sep. 0.128") to NX Pup -- originally discovered by HST -- and measured its JHK magnitudes. A third object at a separation of 7.0" from NX Pup was identified as a classic

Brian Chaboyer

In this review, I will discuss a few problems which point to the need for improved stellar evolution models of halo stars. Current stellar evolution models do not match the observed $^7$Li abundance patterns, suggesting that the input physics and/or the assumptions used in constructing the models are in need of revision. It appears that all halo stars have s

Arjun Berera

Assuming a first order phase transition during inflation, a model scenario is described which does not require a tiny coupling constant. Thermal equilibrium is closely maintained as inflation commences. No large scale reheating is necessary. Solutions for $N> 70$ are found for any $δρ/ ρ$ in the range $10^{-5} - 10^{-3}$.

C. M. Cress, D. J. Helfand, R. H. Becker, R. L. White

The angular two-point correlation function is calculated for the first 300 square degrees of the FIRST radio survey. Results for various subsamples are also obtained. Double-lobed sources are shown to have a higher clustering amplitude than the sample as a whole. Small differences in the correlation function from one region of the sample to another and resul

Yun Wang, Edwin L. Turner

For a given source and lens pair, there is a thin on-axis tube-like volume behind the lens in which the radiation flux from the source is greatly increased due to gravitational lensing. Any objects (such as dust grains) which pass through such a thin tube will experience strong bursts of radiation, i.e., Extreme Gravitational Lensing Events (EGLE). We study

A. V. Ilinskaia, K. N. Ilinski, G. V. Kalinin, V. V. Melezhik

Basing on the picture of Frenkel excitons in molecular crystals described by the XY-model we consider the linear response of linear cyclic aggregates at finite temperature. The exact results for characteristics of the response are obtained. In particular, we calculate time-dependent two-point correlation functions at finite temperature for the cyclic 1-D XY-

Morris L. Swartz

We reevaluate the hadronic part of the electromagnetic vacuum expectation value using the standard dispersion integral approach that utilizes the hadronic cross section measured in $\ee$ experiments as input. Previous analyses are based upon point-by-point trapezoidal integration which does not treat experimental errors in an optimal way. We use a technique

B. Ali, John S. Carr, D. L. DePoy, Jay A. Frogel

We present an atlas of moderate resolution ($λ/Δλ\sim$1380) 2.15~\micron\ to 2.39~\micron\ spectra of 33 luminosity class V stars of spectral type F3 to M6 in the MK classification system. We find that the equivalent widths of several spectral features vary significantly with temperature and typically allow effective temperature determination accurate to app

Friedemann Brandt, Walter Troost, Antoine Van Proeyen

We compute completely the BRST--antibracket cohomology on local functionals in two-dimensional Weyl invariant gravity for given classical field content (two dimensional metric and scalar matter fields) and gauge symmetries (two dimensional diffeomorphisms and local Weyl transformations). This covers the determination of all classical actions, of all their ri

Pradip K Sahu

In two - loop effective Lagrangian, the low - temperature expansion of the $QED_{3+1}$ with a constant magnetic field and a finite chemical potential is performed. We then calculate the total fermion density, some components of polarization operator and de Hass -van Alphen oscillations. We find that there is a significant contribution from two-loop expansion

Pradip K Sahu

We study the effect of a magnetic field on the interacting quark matter and apply to strange star. We considere the low temperature approximation to strange matter. We find that the interacting strange quark matter is more stable compare to free quark gas in presence of strong external magnetic field with zero and finite temperature. We then calculate strang

M. Chertkov, G. Falkovich

For Kraichnan's problem of passive scalar advection by a velocity field delta-correlated in time, the limit of large space dimensionality $d\gg1$ is considered. Scaling exponents of the scalar field are analytically found to be $ζ_{2n}=nζ_2-2(2-ζ_2)n(n-1)/d$, while those of the dissipation field are $μ_{n}=-2(2-ζ_2)n(n-1)/d$ for orders $n\ll d$. The refi

M. A. Semenov-Tian-Shansky, A. V. Sevostyanov

We classify nonultralocal Poisson brackets for 1-dimensional lattice systems and describe the corresponding regularizations of the Poisson bracket relations for the monodromy matrix . A nonultralocal quantum algebras on the lattices for these systems are constructed.For some class of such algebras an ultralocalization procedure is proposed.The technique of t

Asher Peres

This is a Comment on Phys Rev Lett 75 (1995) 1239, by Goldenberg and Vaidman

Masaki Satoh

As a tool for understanding the meridional circulation of the atmosphere, a two-dimensional ( latitude -- height ) numerical model is used to clarify the relationship between the Hadley circulation and large-scale motions associated with moist convection. The model is based on the primitive equations including the moist process, and two kinds of coordinates

R. D. Peccei, K. Wang

We introduce the idea of natural mass matrices, an organizing principle useful in the search for GUT scale quark mass matrix patterns that are consistent with known CKM constraints and quark mass eigenvalues. An application of this idea is made in the context of SUSY GUTs and some potentially ``successful'' GUT scale mass patterns are found. The CKM

J. F. van Diejen

Recent results are surveyed regarding the spectrum and eigenfunctions of the inverse square Calogero model with harmonic confinement and its relativistic analogue.

T. A. Welsh

In this paper, we initiate a study into the explicit construction of irreducible representations of the Hecke algebra $H_n(q)$ of type $A_{n-1}$ in the non-generic case where $q$ is a root of unity. The approach is via the Specht modules of $H_n(q)$ which are irreducible in the generic case, and possess a natural basis indexed by Young tableaux. The general

Sanjay K. Ghosh, S. C. Phatak

We investigate the properties of quark matter at finite density and temperature using the nonlinear chiral extension of Colour Dielectric Model (CCM). Assuming that the square of the meson fields devlop non- zero vacuum expectation value, the thermodynamic potential for interacting three flavour matter has been calculated. It is found that $<K^2>$ and $<η^2>

L. Engvik, G. Bao, M. Hjorth-Jensen, E. Osnes

In this work we calculate the total mass, radius, moment of inertia, and surface gravitational redshift for neutron stars using various equations of state (EOS). Modern meson-exchange potential models are used to evaluate the $G$-matrix for asymmetric nuclear matter. We calculate both a non-relativistic and a relativistic EOS. Of importance here is the fact

A. S. Rinat, M. F. Taragin

We study the transparency $\cal T$ of nuclei for nucleons knocked-out in high-energy semi-inclusive $(e,e&#39;p)$ reactions, using an improved theoretical input, discussed by Nikolaev et al. We establish that neglect of $NN$-correlations between the knocked-out and core nucleons reduces nuclear transparencies by $\approx 15 \%$ for light, to $\approx 10\%$ f

J. Brian Conrey

We give explicit formulae for all of the terms in the asymptotic expansion of the mean fourth power of the Riemann zeta-function on the critical line.

Feliks Przytycki

Let $f:\bar\bold C\to\bar\bold C$ be a rational map on the Riemann sphere , such that for every $f$-critical point $c\in J$ which forward trajectory does not contain any other critical point, $|(f^n)&#39;(f(c))|$ grows exponentially fast (Collet--Eckmann condition), there are no parabolic periodic points, and else such that Julia set is not the whole sphere.

Lars Brink, Mikhail Vasiliev

In this paper we introduce a unified approach to Toda field theories which allows us to formulate the classes of $A_n$, $B_n$ and $C_n$ models as unique models involving an arbitrary continuous parameter $ν$. For certain values of $ν$, the model describes the standard Toda theories. For other values of $ν$ it defines a class of models that involve infinitely

S. Lukyanov

A current of the deformed Virasoro algebra is identified with the Zamolodchikov-Faddeev operator for the basic scalar particle in the XYZ model.

S. S. Pinsky, A. C. Kalloniatis

We consider adjoint scalar matter coupled to QCD(1+1) in light-cone quantization on a finite `interval&#39; with periodic boundary conditions. We work with the gauge group SU(2) which is modified to ${\rm{SU(2)/Z_2}}$ by the non-trivial topology. The model is interesting for various nonperturbative approaches because it is the sector of zero transverse momen

E. Langmann, J. Mickelsson

We discuss several aspects of second quantized scattering operators $\hat S$ for fermions in external time dependent fields. We derive our results on a general, abstract level having in mind as a main application potentials of the Yang--Mills type and in various dimensions. We present a new and powerful method for proving existence of $\hat S$ which is also

Harald H. Soleng

The exact solution for a static spherically symmetric field outside a charged point particle is found in a non-linear $U(1)$ gauge theory with a logarithmic Lagrangian. The electromagnetic self-mass is finite, and for a particular relation between mass, charge, and the value of the non-linearity coupling constant, $λ$, the electromagnetic contribution to the

S. H. Guo, Q. Z. Chen, X. Fang, J. Liu

We review our new method, which might be the most direct and efficient way for approaching the continuum physics from Hamiltonian lattice gauge theory. It consists of solving the eigenvalue equation with a truncation scheme preserving the continuum limit. The efficiency has been confirmed by the observations of the scaling behaviors for the long wavelength v

Leonardo Castellani, Alberto Perotto

The gauging of free differential algebras (FDA&#39;s) produces gauge field theories containing antisymmetric tensors. The FDA&#39;s extend the Cartan-Maurer equations of ordinary Lie algebras by incorporating p-form potentials ($p > 1$). We study here the algebra of FDA transformations. To every p-form in the FDA we associate an extended Lie derivative $\ell

Alexey Sevostyanov

The canonical Poisson structure of nonlinear sigma-model is presented as a Lie-Poisson r-matrix bracket on coadjoint orbits. It is shown that the Poisson structure of this model is determined by some `hidden singularities&#39; of the Lax matrix.

Sergio Lupia, Wolfgang Ochs

The spectra of charged particles in the energy variable $ξ= \log 1/x$ (``the hump backed plateau&#39;&#39;) are analyzed in terms of moments in order to investigate the sensitivity to the running of $α_s$ in particular towards small scales, and to further test thereby the local parton hadron duality picture. The modified leading log approximation (MLLA) of Q

F. E. Close, J. R. Forshaw

We propose a means of distinguishing between gluon- and quark-seeded systems that may in principle be measured in deep inelastic lepton scattering. As a particular application, we discuss those HERA data on deep inelastic $ep$ scattering which contain a large rapidity gap in the final state. It is standard to interpret these events as being due to ``pomeron&

M. Vysotsky

Lecture at 23 ITEP Winter School. Manifestations of heavy top at low energies (K- and B-mesons) and high energies (Z and W physics) are discussed

Frank Close

The lightest scalar glueball and ground state hybrids may have been found. I compare signals reported at this conference with theoretical expectations and highlight the questions that need to be addressed in forthcoming experiments.

F. M. Steffens, A. W. Thomas

There has recently been surprising progress in understanding the spin and flavor dependence of deep inelastic structure functions in terms of the same physics needed in the simple quark models used for hadronic spectroscopy. However, the corresponding scale is usually very low, casting doubt on the use of leading order $QCD$ evolution. We show that the concl

Takayuki Matsuki

Operating just once the naive Foldy-Wouthuysen-Tani transformation on the Schrödinger equation for $Q\bar q$ bound states described by a hamiltonian, we systematically develop a perturbation theory in $1/m_Q$ which enables one to solve the Schrödinger equation to obtain masses and wave functions of the bound states in any order of $1/m_Q$. It is shown that p

Anupam Singh

To optimally utilize all the exciting cosmological data coming in we need to sharpen also the theoretical tools available to cosmologists. One such indispensible tool to understand hot big bang cosmology is finite temperature field theory. We review and summarise the efforts made by us to use finite temperature field theory to address issues of current inter

Urs M. Heller

We present further evidence for the bulk nature of the phase transition line in the fundamental--adjoint action plane of SU(3) lattice gauge theory. Computing the string tension and some glueball masses along the thermal phase transition line of finite temperature systems with $N_t=4$, which was found to join onto the bulk transition line at its endpoint, we

Ch. Hoelbling, A. Jakovac, J. Jersak, C. B. Lang

We present results for 2D and 4D systems on lattices with topology homotopic to the surface of a (hyper) sphere $S^2$ or $S^4$. Finite size scaling is studied in situations with phase transitions of first and second order type. The Ising and Potts models exhibit the expected behaviour; for the 4D pure gauge $U(1)$ theory we find consistent scaling indicative

S. Aoki

The phase structure of lattice QCD with Wilson fermions is discussed. Analytic and numerical evidences are given for the spontaneous breaking of parity and flavor symmetry, which naturally explains the existence of the massless pion at the critical hopping parameter $K_c$ without recourse to the chiral symmetry absent in the Wilson fermion formulation. New n

Rhett Herman, William A. Hiscock

The DeWitt-Schwinger proper time point-splitting procedure is applied to a massive complex scalar field with arbitrary curvature coupling interacting with a classical electromagnetic field in a general curved spacetime. The scalar field current is found to have a linear divergence. The presence of the external background gauge field is found to modify the st

Rafael A. Vera

An extremely simple and unified base for physics comes out by starting all over from a single postulate on the common nature of matter and stationary forms of radiation quanta. Basic relativistic, gravitational (G) and quantum mechanical properties of a standing wave particle model have been derived. This has been done from just dual properties of radiation&

H. Haugerud, F. Ravndal

The Bose-Einstein condensation of a dilute gas of rubidium-87 atoms was achieved by cooling a small number of atoms in a magnetic trap. The effective potential of the trap is to lowest order harmonic and under these conditions we estimate the critical temperature and the heat capacity of an ideal gas of Bose particles. Previously this has been estimated with

Prasanta K. Panigrahi, M. Sivakumar

Making use of the well-known phase space reduction in the lowest Landau level(LLL), we show that the Laughlin wave function for the $ν= {1\over m}$ case can be obtained exactly as a coherent state representation of an one dimensional $(1D)$ wave function. The $1D$ system consists of $m$ copies of free fermions associated with each of the $N$ electrons, confi

B. Bergersen, Z. Racz, H. -J. Xu

Two-spin correlations generated by interactions which decay with distance r as r^{-1-sigma} with -1 <sigma <0 are calculated for periodic Ising chains of length L. Mean-field theory indicates that the correlations, C(r,L), diminish in the thermodynamic limit L -> \infty, but they contain a singular structure for r/L -> 0 which can be observed by introducing

C. Reichhardt, C. J. Olson, J. Groth, Stuart Field

We present a microscopic derivation, without electrodynamical assumptions, of $B(x,y,H(t))$, $M(H(t))$, and $J_c(H(t))$, in agreement with experiments on strongly pinned superconductors, for a range of values of the density and strength of the pinning sites. We numerically solve the overdamped equations of motion % dynamics of these flux-gradient-driven vort

P. Azaria, P. Lecheminant, D. mouhanna

We study the classical ${SU(N)\otimes U(1)/SU(N-1)\otimes U(1)}$ Non Linear Sigma model which is the continuous low energy effective field theory for $N$ component frustrated spin systems. The $β$ functions for the two coupling constants of this model are calculated around two dimensions at two loop order in a low temperature expansion. Our study is complete

R. Melin, J. C. Angles d&#39;Auriac, P. Chandra, B. Doucot

We present a detailed study of the nearest-neighbor ferromagnetic Ising model on a Cayley tree. In the limit of zero field, the system displays glassy behavior below a crossover temperature, $T_g$, that scales inversely with the logarithm of the number of generations; thus $T_g$ is inversely proportional to the logarithm of the logarithm of the number of sit

K. Kusakabe, H. Aoki

A persistent current, coupled with the spin state, of purely many-body origin is shown to exist in Nagaoka&#39;s ferromagnetic state in two dimensions (2D). This we regard as a manifestation of a gauge field, which comes from the surrounding spin configuration and acts on the hole motion, being coupled to the Aharonov-Bohm flux. This provides an example wher

Nandini Trivedi, Richard T. Scalettar, Mohit Randeria

We study an electronic model of a 2D superconductor with onsite randomness using Quantum Monte Carlo simulations. The superfluid density is used to track the destruction of superconductivity in the ground state with increasing disorder. The non-superconducting state is identified as an insulator from the temperature dependence of its d.c. resistivity. The va

Mark Lauer

In this paper I address the practical concern of predicting how much training data is sufficient for a statistical language learning system. First, I briefly review earlier results and show how these can be combined to bound the expected accuracy of a mode-based learner as a function of the volume of training data. I then develop a more accurate estimate of

Mark Lauer

In this paper I explore a number of issues in the analysis of data requirements for statistical NLP systems. A preliminary framework for viewing such systems is proposed and a sample of existing works are compared within this framework. The first steps toward a theory of data requirements are made by establishing some results relevant to bounding the expecte

R. Benzi, L. Biferale, S. Ciliberto, M. V. Struglia

In this letter we present numerical and experimental results on the scaling properties of velocity turbulent fields in the range of scales where viscous effects are acting. A generalized version of Extended Self Similarity capable of describing scaling laws of the velocity structure functions down to the smallest resolvable scales is introduced. Our findings

K. Mannheim, M. Schulte, J. Rachen

We predict that the UV bump spectrum of quasars extends into the soft X-ray range with a steep power law. For radio-louds, the spectral index is alpha_s ~ 1.7 (S_nu = S_o nu^-alpha), and for radio-quiets it should be somewhat steeper alpha_s >~ 1.7. The prediction is based on a simple scenario in which all quasars, radio-quiets and radio-louds, are assumed t

Roman Scoccimarro, Joshua Frieman

Using a diagrammatic approach to Eulerian perturbation theory, we analytically calculate the variance and skewness of the density and velocity divergence induced by gravitational evolution from Gaussian initial conditions, including corrections *beyond* leading order. Except for the power spectrum, previous calculations in cosmological perturbation theory ha

Michael A. Nowak

We present here a review of high energy (> 1 keV) observations of seven black hole candidates, six of which have estimated masses. In this review we focus on two parameters of interest: the ratio of ``non-thermal&#34; to total luminosity as a function of the total luminosity divided by the Eddington luminosity, and the root mean square (rms) variability as a

Emory F. Bunn, Yehuda Hoffman, Joseph Silk

We apply a Wiener filter to the two-year COBE DMR data. The resulting sky map has significantly reduced noise levels compared to the raw data: the most prominent hot and cold spots are significant at the 4-sigma level. Furthermore, the entire covariance matrix of the errors in the filtered sky map is known, and it is therefore possible to make constrained re

Yun Wang

A small volume of space, nearly on-axis behind a gravitational lens with respect to a given source, will receive a greatly increased radiation flux. In the idealized case of a point mass lens acting on a point source in complete isolation, the volume will approach zero only as the flux tends to infinity; in fact, the volume weighted rms flux is divergent. In

P. R. Wozniak, K. Z. Stanek

We propose a new method to investigate the coefficient of the selective extinction, based on two band photometry. This method uses red clump stars as a means to construct the reddening curve. We apply this method to the OGLE color-magnitude diagrams to investigate the variations of the selective extinction towards various parts of the Galactic bulge. We find

G. R. Meurer, T. M. Heckman, C. Leitherer, A. Kinney

Hubble Space Telescope ultraviolet (UV) images of nine starburst galaxies reveal them to be highly irregular, even after excluding compact sources (clusters and resolved stars). Most (7/9) are found to have a similar intrinsic effective surface brightnesses, suggesting that a negative feedback mechanism is setting an upper limit to the star formation rate pe

Ewa Szuszkiewicz, Matthew A. Malkan, Marek A. Abramowicz

We reexamine the hypothesis that the optical/UV/soft X-ray continuum of Active Galactic Nuclei is thermal emission from an accretion disk. Previous studies have shown that fitting the spectra with the standard, optically thick and geometrically thin accretion disk models often led to luminosities which contradict the basic assumptions adopted in the standard

H. Dejonghe, V. De Bruyne, P. Vauterin, W. W. Zeilinger

Using the photometry and the kinematic data, part of which acquired with the NTT, we constructed a 2-integral and a 3-integral distribution function for NGC 4697. We detected a nuclear dust lane at $3.4&#39;&#39;$ or 0.4 kpc from the centre. A comparison of the Lucy-deprojection method and the multi-gaussian expansion method showed that the latter offers a n

Douglas Scott

We are now beginning to learn detailed information about cosmological parameters from the shapes of the matter and radiation power spectra, together with their relative normalization. As more high quality data are gathered from galaxy surveys and from microwave anisotropies, the range of allowed models is expected to get incrementally smaller. The amount of