July 1994 arXiv papers — page 8

Hsin-Hsi Chen, Yue-Shi Lee

The sampling problem in training corpus is one of the major sources of errors in corpus-based applications. This paper proposes a corrective training algorithm to best-fit the run-time context domain in the application of bag generation. It shows which objects to be adjusted and how to adjust their probabilities. The resulting techniques are greatly simplifi

Frederick H. Willeboordse, Kunihiko Kaneko

The pattern dynamics of the one-way coupled logistic lattice which can serve as a phenomenological model for open flow is investigated and shown to be extremely rich. For medium and large coupling strengths, we find spatially periodic, quasiperiodic and chaotic patterns with temporal periodicity and analyze their stability with the help of a newly introduced

F. Governato, M. Colpi, L. Maraschi

This paper presents results of a series of numerical N-body experiments that describe the merging of galaxy pairs containing a massive black hole in their core. The aim is to study the orbital evolution of the two black holes through the merger event. It is found that merging does NOT lead to the formation of a CLOSE black hole pair} at the center of the rem

Dan Maoz

The results of recent AGN monitoring campaigns confirm the ``big picture'' of the echo paradigm, but the details of the emission-line light curves cannot be accurately reproduced with only the simplest assumptions, some of which must be invalid. I discuss possible solutions. I present some preliminary optical light curves from Wise Observatory for NG

Alexei A. Starobinsky, Jun'ichi Yokoyama

Behaviour of a weekly self-interacting scalar field with a small mass in the de Sitter background is investigated using the stochastic approach (including the case of a double-well interaction potential). Existence of the de Sitter invariant equilibrium quantum state of the scalar field in the presence of interaction is shown for any sign of the mass term. T

Ziad Maassarani

In this paper I construct lattice models with an underlying $U_q osp(2,2)$ superalgebra symmetry. I find new solutions to the graded Yang-Baxter equation. These {\it trigonometric} $R$-matrices depend on {\it three} continuous parameters, the spectral parameter, the deformation parameter $q$ and the $U(1)$ parameter, $b$, of the superalgebra. It must be emph

Jonathan Rosenberg, Stephan Stolz

We discuss a conjecture of Gromov and Lawson, later modified by Rosenberg, concerning the existence of metrics of positive scalar curvature. It says that a closed spin manifold $M$ of dimension $n\ge 5$ has such a metric if and only if the index of a suitable ``Dirac" operator in $KO_n(C^* (\pi_1(M)))$, the real $K$-theory of the group $C^*$-algebra of the f

E. G. Floratos, G. K. Leontaris

We present analytic expressions for the top and bottom Yukawa couplings in the context of the minimal supersymmetric standard model when both couplings $h_{t,0},h_{b,0}$ are large at the unification scale. For sufficiently large $h_{t,0},h_{b,0}$, i.e. within $\sim (20-25)\% $ close to their fixed point values, using as input the central value of the bottom

E. Gotsman, E. M. Levin, U. Maor

The role of screening corrections, calculated using the eikonal model, is discussed in the context of soft photoproduction. We present a comprehensive calculation considering the total,elastic and diffractive cross sections jointly. We examine the differences between our results and those obtained from the supercritical Pomeron-Reggeon model with no unitarit

A. E. Dorokhov

The estimations of the light quark mass differences, $m_d-m_u$, and the light quark condensate differences, $<\bar DD> - <\bar UU>$, are obtained in the framework of the \qm\ with QCD vacuum induced \q\ \ia . We consider long - wave condensate and short - wave \s\ contributions to the electromagnetic \hn\ mass \di s and show that the latter significantly imp

Sanjay K. Ghosh, S. C. Phatak, Pradip K. Sahu

We investigate the properties of hybrid stars consisting of quark matter in the core and hadron matter in outer region. The hadronic and quark matter equations of state are calculated by using nonlinear Walecka model and chiral colour dielectric (CCD) model respectively. We find that the phase transition from hadron to quark matter is possible in a narrow ra

T. Vetter T. S. Biro U. Mosel

A transport theory is developed on the quark level to describe nucleon--nucleon collisions. We treat the strong interaction effectively by the Friedberg-Lee model both in its original and in its modified confining version. First we study the stability of the static three-dimensional semiclassical configuration, then we present results of the time evolution g

W. Melnitchouk, A. W. Schreiber, A. W. Thomas

We calculate the unpolarised deep inelastic structure function of a relativistic deuteron within a covariant framework. An exact treatment of nucleon off-shell effects is shown to give corrections to the widely-used convolution model, even in impulse approximation. Neglecting off-shell effects in the extraction of the neutron structure function from deuteriu

Yair Minsky

We study the Teichmüller metric on the Teichmüller space of a surface of finite type, in regions where the injectivity radius of the surface is small. The main result is that in such regions the Teichmüller metric is approximated up to bounded additive distortion by the sup metric on a product of lower dimensional spaces. The main technical tool in the proof

D. Caenepeel, M. Leblanc

We present the one-loop scalar field effective potential for the $N=2$ supersymmetric nonrelativistic self-interacting matter fields coupled to an Abelian Chern-Simons gauge field and for its generalization when bosonic matter fields are coupled to non-Abelian Chern-Simons field. In both models, Gauss&#39;s law linearly relates the magnetic field to the matt

D. Caenepeel, M. Leblanc

We present an alternative to the Higgs mechanism to generate masses for non-abelian gauge fields in (3+1)-dimensions. The initial Lagrangian is composed of a fermion with current-current and dipole-dipole type self-interactions minimally coupled to non-abelian gauge fields. The mass generation occurs upon the fermionic functional integration. We show that by

J. C. Breckenridge, M. J. Lavelle, T. G. Steele

We consider the Nielsen identities for the two-point functions of full QCD and QED in the class of Lorentz gauges. For pedagogical reasons the identities are first derived in QED to demonstrate the gauge independence of the photon self-energy, and of the electron mass shell. In QCD we derive the general identity and hence the identities for the quark, gluon

Riccardo Guida, Kenichi Konishi, Hiroshi Suzuki

We prove that the linear delta expansion for energy eigenvalues of the quantum mechanical anharmonic oscillator converges to the exact answer if the order dependent trial frequency $Ω$ is chosen to scale with the order as $Ω=CN^γ$; $1/3<γ<1/2$, $C>0$ as $N\rightarrow\infty$. It converges also for $γ=1/3$, if $C\geqα_c g^{1/3}$, $α_c\simeq 0.570875$, where $g

Avinash Dhar, Porus Lakdawala, Gautam Mandal, Spenta R. Wadia

We consider 2-dimensional QCD on a cylinder, where space is a circle of length $L$. We formulate the theory in terms of gauge-invariant gluon operators and multiple-winding meson (open string) operators. The meson bilocal operators satisfy a $W_\infty$ current algebra. The gluon sector (closed strings) contains purely quantum mechanical degrees of freedom. T

S. L. Shatashvili, C. Vafa

The condition of having an $N=1$ spacetime supersymmetry for heterotic string leads to 4 distinct possibilities for compactifications namely compactifications down to 6,4,3 and 2 dimensions. Compactifications to 6 and 4 dimensions have been studied extensively before (corresponding to $K3$ and a Calabi-Yau threefold respectively). Here we complete the study

E. V. Damaskinsky, M. A. Sokolov

In this letter some properties of the Gauss decomposition of quantum group $GL_q(n)$ with application to q-bosonization are considered.

Damiano Anselmi

We go on in the program of investigating the removal of divergences of a generical quantum gauge field theory, in the context of the Batalin-Vilkovisky formalism. We extend to open gauge-algebrae a recently formulated algorithm, based on redefinitions $δλ$ of the parameters $λ$ of the classical Lagrangian and canonical transformations, by generalizing a well

P. H. Damgaard, R. Sollacher

We present an extension of ``smooth bosonization&#39;&#39; to the non-Abelian case. We construct an enlarged theory containing both bosonic and fermionic fields which exhibits a local chiral gauge symmetry. A gauge fixing function depending on one real parameter allows us to interpolate smoothly between a purely fermionic and a purely bosonic representation.

R. Percacci, E. Sezgin

We study the target-space duality transformations in $p$--branes as transformations which mix the worldvolume field equations with Bianchi identities. We consider an $(m+p+1)$-dimensional spacetime with $p+1$ dimensions compactified, and a particular form of the background fields. We find that while a $GL(2)=SL(2)\times R$ group is realized when $m=0$, only

Mario Bergeron, Gordon W. Semenoff, Richard J. Szabo

We consider BF-type topological field theory coupled to non-dynamical particle and string sources on spacetime manifolds of the form $\IR^1\times\MT$, where $\MT$ is a 3-manifold without boundary. Canonical quantization of the theory is carried out in the Hamiltonian formalism and explicit solutions of the Schrödinger equation are obtained. We show that the

Ryusuke Endo

The heat kernel for the spin-3/2 Rarita-Schwinger gauge field on an arbitrary Ricci flat space-time ($d>2$) is investigated in a family of covariant gauges with one gauge parameter $α$. The $α$-dependent term of the kernel is expressed by the spin-1/2 heat kernel. It is shown that the axial anomaly and the one-loop divegence of the action are $α$-independent

Patrick Labelle

In T.Zhang, L.Xiao and R.Koniuk, Can. J. Phys. {\bf 70}, 670 (1992), a new method was developed to calculate energy levels in QED nonrelativistic bound states, up to order m α^5. Whether or not this method could be used beyond this order was left as an open question. In this paper, we answer this question with the help of a nonrelativistic effective field th

D. Lehner

A study of the Standard Model reaction $\e^+e^- \rightarrow (\Z^0\Z^0) \rightarrow f_1\bar{f_1}f_2\bar{f_2}$ including the effects of the finite $\Z^0$~width and initial state radiative corrections is presented. All angular phase space integrations are performed analytically. The remaining invariant masses are integrated numerically. Semi-analytical and nume

Michael S. Chanowitz

I review the physics prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking.

B. V. Geshkenbein, V. L. Morgunov

It is shown that the model used in [1] for the description of the experimental function $R_c (s)$ in the form of a sum of $δ$-functions and the plateau contradicts the Wilson operator expansion (O.E.) in the terms due to the gluon condensate. A QCD model with an infinite number of vector mesons [12,13] does satisfy the requirements of the O.E. for masses and

B. V. Geshkenbein, V. L. Morgunov

A QCD model with an infinite number of vector mesons suggested by one of the authors is used to derive the value of the correction $δα_{hadr}$ for $α(m_{Z}^{2})$ due to the strong interactions. The result is $δα_{hadr} = 0.0275(2)$ ; thus $α(m^{2}_{Z}) = (128.96(3))^{-1}$.

A. Pich, J. Prades

We summarize the present knowledge on the non-perturbative hadronic inputs needed in the analysis of $B^0$-$\bar B^0$ mixing and the CP-violating parameter $\varepsilon$ of the $K^0$-$\bar K^0$ system. Using this information, together with the recently determined value of the top-quark mass, we update the phenomenological constraints on the unitarity triangl

R. Muñoz-Tapia, W. J. Stirling

A study of $3+1$ jet event photoproduction at HERA is presented. We define an angular variable which is sensitive to the topology of the final state jets and is therefore able to discriminate between the different contributing subprocesses, and between QCD and an abelian gluon model. We also investigate the contribution from the direct production of light gl

Jean-Marc Richard

We review the spectroscopy and some properties of hadrons containing two charmed quarks, or more generally, two heavy quarks. This includes heavy baryons such as $(bcu)$, and possible exotic multiquark states.

K. J. Abraham, J. Kalinowski, P. Sciepko

We investigate the sensitivity of single photon plus missing energy cross-sections at future $e^{+}e^{-}$ linacs to non-standard $WWγ$ couplings. We show that even with conservative estimates of systematic errors there is still considerable sensitivity to anomalous couplings. Analytic expressions for helicity amplitudes are presented.

A. N. Vall, V. M. Leviant, A. V. Sinitskaya

In the paper we consider non-relativistic analog of the Nambu-Jona-Lasinio model and demonstrate, by this most simplified example, the method of dynamical mappings of Heisenberg fields on &#34;physical&#34; fields. We obtain the expressions for one particle eigen-excitation spectrum of full Hamiltonian (spectrum of &#34;clad&#34; fermions), wave function of

A. N. Vall, S. I. Korenblit, V. M. Leviant, A. V. Sinitskaya

In these notes for the quark Nambu-Jona-Lasinio model and for the phenomenological four fermionic model of QCD we analyze vacuum energy structure and calculate dependence of energy of one-particle excitations on momentum. We reveal existence of two different types of excitations above the vacuum with the respective minimization of the vacuum energy density.

A. Patrascioiu, E. Seiler

We point out that the $1/N$ expansion, which is widely invoked to infer properties of the $2D$ $O(N)$ models, is nonuniform in the temperature, i.e. with decreasing temperature the $1/N$ expansion truncated at a fixed order deviates more and more from the true answer. This fact precludes the use of the expansion to deduce low temperature properties such as a

Kayll Lake

A one-fold infinity of explicit quasi-stationary regular line elements for the Schwarzschild geometry is obtained directly from the vacuum Einstein equations. The class includes the familiar Eddington-Finkelstein coordinates, and the coordinates discussed recently by Kraus and Wilczek.

William Bruckman

The field equations of the scalar-tensor theories of gravitation are presented in different representations, related to each other by conformal transformations of the metric. One of the representations resembles the Jordan-Brans-Dicke theory, and is the starting point for the generation of exact electrostatic and magnetostatic exterior solutions. The corresp

P. A. Rikvold, B. M. Gorman

We review some aspects of current knowledge regarding the decay of metastable phases in many-particle systems. In particular we emphasize recent theoretical and computational developments and numerical results regarding homogeneous nucleation and growth in kinetic Ising and lattice-gas models. An introductory discussion of the droplet theory of homogeneous n

J. K. Freericks, E. H. Lieb

The many-body ground state of a very general class of electron-phonon Hamiltonians is proven to contain a spin singlet (for an even number of electrons on a finite lattice). The phonons interact with the electronic system in two different ways---there is an interaction with the local electronic charge and there is a functional dependence of the electronic ho

M. L. Plumer, A. Mailhot

Histogram analysis of Monte-Carlo simulation results of the Ising antiferromagnet on a stacked triangular lattice are reported. Finite-size scaling estimates for critical exponents suggest $XY$ universality. This result supports earlier predictions based on symmetry arguments and is in contrast with a recent suggestion of a new universality class by Bunker {

Lin-Yuan Chen, Nigel Goldenfeld, Y. Oono

We show with several examples that renormalization group (RG) theory can be used to understand singular and reductive perturbation methods in a unified fashion. Amplitude equations describing slow motion dynamics in nonequilibrium phenomena are RG equations. The renormalized perturbation approach may be simpler to use than other approaches, because it does n

I. V. Krive, P. Sandström, R. I. Shekhter, M. Jonson

The influence of long-range Coulomb forces on the persistent current of a pinned Wigner crystal-ring is considered. A simple method is proposed for how to take into account Coulomb effects for the macroscopic quantum tunneling of the Wigner crystal. It is shown that unscreened Coulomb interactions increase the stiffness of the Wigner lattice. This leads to a

David P. Divincenzo

A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are sufficient to construct a general quantum circuit. The best previous result had shown the universality of three-bit gates, by analogy to the universality of the Toffoli three-bit gate of classical reversible computin

Gregory Eyink, Nigel Goldenfeld

We discuss two distinct analogies between turbulence and field theory. In one analogue, the field theory has an infrared attractive renormalization-group fixed point and corresponds to critical phenomena. In the other analogue, the field theory has an ultraviolet attractive fixed point, as in quantum chromodynamics.

B. Mendez, F. Dominguez-Adame

We have theoretically investigated two-band models of graded-gap superlattices within the envelope-function approximation. Assuming that the gap varies linearly with spatial coordinate, we are able to find exact solutions of the corresponding Dirac-like equation describing the conduction- and valence-band envelope-functions. The dispersion relation inside al

Werner Krauth, Olivier Pluchery

In this paper we present a dynamical Monte Carlo algorithm which is applicable to systems satisfying a clustering condition: during the dynamical evolution the system is mostly trapped in deep local minima (as happens in glasses, pinning problems etc.). We compare the algorithm to the usual Monte Carlo algorithm, using as an example the Bernasconi model. In

John Dowding, Jean Mark Gawron, Doug Appelt, John Bear

Gemini is a natural language understanding system developed for spoken language applications. The paper describes the architecture of Gemini, paying particular attention to resolving the tension between robustness and overgeneration. Gemini features a broad-coverage unification-based grammar of English, fully interleaved syntactic and semantic processing in

John Dowding, Robert Moore, Francois Andry, Douglas Moran

We describe an efficient bottom-up parser that interleaves syntactic and semantic structure building. Two techniques are presented for reducing search by reducing local ambiguity: Limited left-context constraints are used to reduce local syntactic ambiguity, and deferred sortal-constraint application is used to reduce local semantic ambiguity. We experimenta

Mitsutaka Matsumoto

(This is not the abstract): The language is Japanese. If your printer does not have fonts for Japases characters, the characters in figures will not be printed out correctly. Dissertation for Bachelor&#39;s degree at Kyoto University(Nagao lab.),March 1994.

Dany Page

We model the temperature distribution at the surface of a magnetized neutron star and study the effects on the observable X-ray spectra and light curves, taking fully into account gravitational lensing. Only dipolar fields are considered here. General features are studied and compared with the ROSAT data from the pulsars 0833-45 (Vela), 0656+14, 0630+178 (Ge

A. Udalski, M. Szymanski, K. Z. Stanek, J. Kaluzny

We present the analysis of the first two years of the OGLE search for gravitational lenses towards the Galactic bulge. We detected 9 microlensing events in an algorithmic search of $ \sim 10^8 $ measurements of $ \sim 10^6 $ stars. The characteristic time scales are in the range $ 8.6 < t_0 < 62 $ days, where $ t_0 = R_E / V $. The distribution of amplitudes

F. Combes, D. Pfenniger

Major progresses have been made this last year towards a better knowledge of the invisible mass. Michel Spiro will talk in details about the micro-lensing experiments and their promising results; the ROSAT satellite has provided extended X-ray maps of the hot gas, which traces dark matter in galaxy clusters: they reveal lower amounts of dark matter in cluste

D. Pfenniger, F. Combes

The conjecture that dark matter in galaxies is mostly cold fractal gas is developed in the more general context of the thermodynamics of the ideal isothermal gas subject to gravitational instability. This simple gas model already contains the contrary ingredients able to prevent an asymptotic equilibrium: any growing gravothermal singularity evaporates in a

Tomas Kopf, Pavel Krtous, Don N. Page

The observation that we are among the first 10^{11} or so humans reduces the prior probability that we find ourselves in a species whose total lifetime number of individuals is much higher, according to arguments of Carter, Leslie, Nielsen, and Gott. However, if we instead start with a prior probability that a history has a total lifetime number which is ver

J. R. Cudell, A. J. Gentles, D. A. Ross

Within the framework of the Dyson-Schwinger equations in the axial gauge, we study the effect that non-perturbative glue has on the quark propagator. We show that Ward-Takahashi identities, combined with the requirement of matching perturbative QCD at high momentum transfer, guarantee the multiplicative renormalisability of the answer. Technically, the match

J. M. Cline

Paper withdrawn; ask me if you would like to know the details.

Sumit R. Das, Sudipta Mukherji

We study the dynamics of the boundary dilaton gravity coupled to N massles scalars. We rederive the boundary conditions of [1] and [3] in a way which makes the requirement of reparametrization invariance and role of conformal anomaly explicit. We then study the semiclassical behaviour of the boundary in the N = 24 theory in the presence of an incoming matter

Steven S. Gubser, Igor R. Klebanov

By introducing a $\int dt \, g\left(\Tr Φ^2(t)\right)^2$ term into the action of the $c=1$ matrix model of two-dimensional quantum gravity, we find a new critical behavior for random surfaces. The planar limit of the path integral generates multiple spherical ``bubbles&#39;&#39; which touch one another at single points. At a special value of $g$, the sum ove

S. Ghigna, S. Borgani, S. Bonometto, L. Guzzo

We use the void probability statistics to study the redshift-space galaxy distribution as described by a volume-limited subsample of the Perseus-Pisces survey. We compare the results with the same analysis realized on artificial samples, extracted from high-resolution N-body simulations by reproducing the observational biases of the real data set. Simulation

B. Paczynski, K. Z. Stanek, A. Udalski, M. Szymanski

The analysis of the first two years of OGLE data revealed 9 microlensing events of the galactic bulge stars, with the characteristic time scales in the range $ 8.6 < t_0 < 62 $ days, where $ t_0 = R_E / V $. The optical depth to microlensing is larger than $ ( 3.3 \pm 1.2 ) \times 10^{-6}$, in excess of current theoretical estimates, indicating a much higher

V. I. Belinicher, A. L. Chernyshev, L. V. Popovich

The t-J model effective hopping integral is determined from the three-band Hubbard model for the charge carriers in CuO$_{2}$ plane. For this purpose the values of the superexchange constant $J$ and the charge-transfer gap $E_{gap}$ are calculated in the framework of the three-band model. Fitting values of $J$ and $E_{gap}$ to the experimental data allows to

A. Yu. Umnikov, L. P. Kaptari, K. Yu. Kazakov, F. C. Khanna

A covariant field theoretical approach to deep inelastic scattering on the deuteron is presented. The deuteron structure function is calculated in terms of the Bethe-Salpeter amplitude. Numerical calculations for the nucleon contribution are made with a realistic model of the $NN$-interaction, including $π$-, $ρ$-, $ω$-, $η$-, $δ$- and $σ$-mesons, and result

G. A. Lalazissis, M. M. Sharma, J. Koenig, P. Ring

We have studied the anomalous behaviour of isotopic shifts of Pb nuclei in the relativistic mean field theory. It has been shown that the relativistic mean field provides an excellent description of the anomalous kink in the isotopic shifts about $^{208}$Pb. This is in contrast from density-dependent Skyrme forces which do not reproduce the observed trend in

Boris Dubrovin

These lecture notes are devoted to the theory of equations of associativity describing geometry of moduli spaces of 2D topological field theories. Introduction. Lecture 1. WDVV equations and Frobenius manifolds. {Appendix A.} Polynomial solutions of WDVV. {Appendix B.} Symmetriies of WDVV. Twisted Frobenius manifolds. {Appendix C.} WDVV and Chazy equation. A

H. Aratyn, E. Nissimov, S. Pacheva, A. H. Zimerman

We show that the 2-matrix string model corresponds to a coupled system of $2+1$-dimensional KP and modified KP ($\KPm$) integrable equations subject to a specific ``symmetry&#39;&#39; constraint. The latter together with the Miura-Konopelchenko map for $\KPm$ are the continuum incarnation of the matrix string equation. The $\KPm$ Miura and Bäcklund transform

Boguslaw Broda

A straightforward relationship between the two approaches to 3-dimensional topological invariants, one of them put forward by Witten in the framework of topological quantum field theory, and the second one proposed by Kohno in terms of rational conformal field theory, is established.

J. Fuchs, A. Ganchev, P. Vecsernyes

We describe the role of Rational Hopf Algebras as the symmetries of rational field theories and discuss their relation with algebraic field theory, braided monoidal categories and modular fusion rule algebras.

G. Domokos, S. Kovesi-Domokos

We give a simple, semianalytic theory of the development of the hadronic and neutrino/muon components of a cascade induced by a primary which produces hadrons at the initial interaction. The main purpose of the theory is to allow the user to obtain quick, but reasonably reliable estimates of the longitudinal properties of such cascades developing in a medium

Wilfried Buchmuller

Recently, the ZEUS collaboration has reported on several remarkable properties of events with a large rapidity gap in deep inelastic scattering. We suggest that the mechanism underlying these events is the scattering of electrons off lumps of wee partons inside the proton. Based on an effective lagrangian approach the $Q^2$-, $x$- and $W$-distributions are e

J. W. Bos, Y. C. Lin, H. H. Shih

We give the amplitude for $γγ\rightarrow π^+π^-π^0$ in leading order chiral perturbation theory. For the case of real photons we calculate the total and differential cross section. Furthermore, we give the dependence of the total cross section on the invariant mass of one of the photons.

F. Zwirner

To increase the predictivity of the Minimal Supersymmetric Standard Model (MSSM), one needs to go to an underlying, more fundamental theory, where at least some of the many MSSM parameters can be determined by symmetries or by dynamics. Progress may come from four-dimensional superstring solutions and their effective supergravities. Summarizing some recent w

Yongseok Oh, Byung-Yoon Park, Dong-Pil Min

We present a consistent way of describing heavy baryons containing a heavy quark as bound states of an $SU(2)$ soliton and heavy mesons. The resulting mass formula reveals the heavy quark symmetry explicitly. By extending the model to the orbitally excited states, we establish the generic structure of the heavy baryon spectrum. As anticipated from the heavy

M. Caselle, R. Fiore, F. Gliozzi, M. Hasenbusch

We compare predictions of the Capillary Wave Model beyond its Gaussian approximation with Monte Carlo results for the energy gap and the surface energy of the 3D Ising model in the scaling region. Our study reveals that the finite size effects of these quantities are well described by the Capillary Wave Model, expanded to two--loop order ( one order beyond t

Peter Goetsch, Robert Graham, Fritz Haake

We discuss the fate of initial states of the cat type for the damped harmonic oscillator, mostly employing a linear version of the stochastic Schrödinger equation. We also comment on how such cat states might be prepared and on the relation of single realizations of the noise to single runs of experiments.

E. Macia, F. Dominguez-Adame

Exciton optical absorption in self-similar aperiodic one-dimensional systems is considered, focusing our attention on Thue-Morse and Fibonacci lattices as canonical examples. The absorption line shape is evaluated by solving the microscopic equations of motion of the Frenkel-exciton problem on the lattice, in which on-site energies take on two values, accord

J. Inarrea, G. Platero, C. Tejedor

We have studied the problem of coherent and sequential tunneling through a double barrier structure, assisted by light considered to be present All over the structure, i,e emitter, well and collector as in the experimental evidence. By means of a canonical transformation and in the framework of the time dependent perturbation theory, we have calculated the t

I. V. Krive, A. A. Nersesyan, M. Jonson, R. I. Shekhter

The influence of long-range Coulomb interactions on the properties of one-dimensional (1D) strongly correlated electron systems in vicinity of the metal-insulator phase transition is considered. It is shown that unscreened repulsive Coulomb forces lead to the formation of a 1D Wigner crystal in the metallic phase and to the transformation of the square-root

F. F. Assaad, S. Biskamp

Starting from the Hofstadter butterfly, we define lattice versions of Landau levels as well as a continuum limit which ensures that they scale to continuum Landau levels. By including a next-neighbor repulsive interaction and projecting onto the lowest lattice Landau level, we show that incompressible ground states exist at filling fractions, $ν= 1/3, 2/5 $

A. Car, V. A. Zagrebnov

We consider dependence of the critical fluctuation operators on the rate of interaction decay for an exactly soluble model of the quantum anharmonic crystal of ferroelectric type. The critical exponents for the abnormal behavior of the displacement and momentum fluctuation operators on the critical line are calculated explicitly.

M. Caselle, F. Gliozzi, U. Magnea

We study the topology of fluid interfaces in the 3D Ising model in the rough phase. It turns out that such interfaces are accurately described as dilute gases of microscopic handles, and the stiffness of the interface increases with the genus. The number of configurations of genus $g$ follows a Poisson-like distribution. The probability per unit area for cre

Mehryar Mohri

Finite-state transducers give efficient representations of many Natural Language phenomena. They allow to account for complex lexicon restrictions encountered, without involving the use of a large set of complex rules difficult to analyze. We here show that these representations can be made very compact, indicate how to perform the corresponding minimization

Mehryar Mohri

Local grammars can be represented in a very convenient way by automata. This paper describes and illustrates an efficient algorithm for the application of local grammars put in this form to lemmatized texts.

Harald Trost, Johannes Matiasek

We present an integrated architecture for word-level and sentence-level processing in a unification-based paradigm. The core of the system is a CLP implementation of a unification engine for feature structures supporting relational values. In this framework an HPSG-style grammar is implemented. Word-level processing uses X2MorF, a morphological component bas

I. Biswas, N. Raghavendra

We determine generators of the rational cohomology algebras of moduli spaces of parabolic vector bundles on a curve, under some `primality&#39; conditions on the parabolic datum. These generators are canonical in a precise sense. Our results are new even for usual vector bundles (i.e., vector bundles without parabolic structure) whose rank is greater than 2

C. Alcock, R. Allsman, T. Axelrod, D. Bennett

The MACHO project carries out regular photometric monitoring of millions of stars in the Magellanic Clouds and Galactic Bulge, to search for very rare gravitational microlensing events due to compact objects in the galactic halo and disk. A preliminary analysis of one field in the Galactic Bulge, containing {$\sim430,000$} stars observed for 190 days, reveal

Holger Bech Nielsen, Svend Erik Rugh, Christian Surlykke

We look at various features of the Standard Model with the purpose of exploring some possibilities of how to seek physical laws beyond it, i.e. at even smaller distances. Only parameters and structure which are not calculable from the Standard Model is considered useful information. Ca. $90$ bits of information contained in the system of representations in t

Holger Bech Nielsen, Svend Erik Rugh

Noticing that really the fermions of the Standard Model are best thought of as Weyl - rather than Dirac - particles (relative to fundamental scales located at some presumably very high energies) it becomes interesting that the experimental space-time dimension is singled out by the Weyl equation: It is observed that precisely in the experimentally true space

Boris Feigin, Vadim Schechtman, Alexander Varchenko

We give an explicit description of &#34;bundles of conformal blocks&#34; in Wess-Zumino-Witten models of Conformal field theory and prove that integral representations of Knizhnik-Zamolodchikov equations constructed earlier by the second and third authors are in fact sections of these bundles.

Toshiya Kawai

Expressions are given for the elliptic genera of the Kazama-Suzuki models associated with hermitian symmetric spaces when the problems of field identifications are absent. We use the models&#39; known Coulomb gas descriptions.

Arjun Berera

A light-cone wavefunction interpretation is presented for the polarized distribution functions $h_1(x)$ and $h_2(x)$. All matrix elements for moments of these distributions are given in terms of overlap integrals between Fock state amplitudes of the target state. In a suitable spinor basis, $h_1(x)$ involves only diagonal matrix elements so can be interprete

Arjun Berera

A methodology is given to test the QCD $N_f$=2 chiral transition, presently conjectured to be second order. Scaling forms for the correlation length, susceptibilities and equation of state are given which account for finite lattice spacing. Confirmation by lattice simulation would provide a large set of consistency checks for establishing that the transition

Aneesh V. Manohar

The large-$N_c$ limit of the meson-baryon effective Lagrangian is shown to reduce to a semiclassical field theory. A chiral bag structure emerges naturally in the $N_c\rightarrow \infty$ limit. A possible connection between the chiral bag picture and the Skyrme model is discussed. The classical meson-baryon theory is used to reproduce the $M_π^3$ non-analyti

Rohini M. Godbole

We discuss in this set of lectures the structure of proton/neutron as revealed through a study of form-factors. This is followed by a discussion of the structure functions of proton/nuclear targets as measured in the deep inelastic scattering (DIS) of leptons off these targets. We discuss the parton model in DIS as well as outline the usage of parton model i

Dmitri Kouznetsov, Roberto Ortega, Daniel Rohrlich

Any quantum device that amplifies coherent states of a field while preserving their phase generates noise. A nonlinear, phase-invariant amplifier may generate less noise, over a range of input field strengths, than any linear amplifier with the same amplification. We present explicit examples of such nonlinear amplifiers, and derive lower bounds on the noise

Manas Sardar, Debanand Sa

It is shown that the single particle band motion along the $c$ axis is harmful for superconductivity. Variation of $T_c$ with $c$ axis hopping parameter is shown for both the conventional planar superconductors and for interlayer pair tunneling mechanism of Wheatley Hsu and Anderson(WHA).Effect of out of plane magnetic impurity substitution is shown to suppr

P. A. Sreeram, Manas Sardar

The peculiarities in tunneling characteristics have been studied in the light of the controversy between s-wave and d-wave character of High $T_c$ superconductivity. We show that anisotropic s-wave gap has the same low voltage power law conductance and two peak structure in the density of states as d-wave superconductors. The asymmetric tunneling conductance

S. Pellegrini

We present the results of the analysis of the ROSAT PSPC pointed observation of the S0 galaxy NGC5866. Previous Einstein observations had revealed that this galaxy has a low X-ray to optical ratio Lx/Lb. Theoretical models of the X-ra emission of early-type galaxies had suggested that in objects of this kind the emission is not dominated by the presence of a