November 1997 arXiv papers — page 10

U. Pustogowa, W. Hubner, K. H. Bennemann

We calculate the linear magneto-optical Kerr rotation for CeSb in the near-infrared spectral range. Using an exact formula for large Kerr rotation angles and a simplified electronic structure of CeSb we find at \hbar ω= 0.46 eV a Kerr rotation of 90 degree which then for decreasing ωjumps to -90 degree as recently observed. We identify the general origin of

Masatoshi Imada

Small Drude weight $D$ together with small specific heat coefficient $γ$ observed in the ferromagnetic phase of R$_{1-x}$A$_x$MnO$_3$ (R=La, Pr, Nd, Sm; A=Ca, Sr, Ba) are analyzed in terms of a proximity effect of the Mott insulator. The scaling theory for the metal-insulator transition with the critical enhancement of orbital correlations toward the stagger

Corey Miller, Orhan Karaali, Noel Massey

We describe the approach to linguistic variation taken by the Motorola speech synthesizer. A pan-dialectal pronunciation dictionary is described, which serves as the training data for a neural network based letter-to-sound converter. Subsequent to dictionary retrieval or letter-to-sound generation, pronunciations are submitted a neural network based postlexi

Christopher D. Manning, Bob Carpenter

We introduce a novel parser based on a probabilistic version of a left-corner parser. The left-corner strategy is attractive because rule probabilities can be conditioned on both top-down goals and bottom-up derivations. We develop the underlying theory and explain how a grammar can be induced from analyzed data. We show that the left-corner approach provide

Vahe' Petrosian, Nicole M. Lloyd-Ronning

We argue that recent observations of afterglows and some theoretical considerations indicate that the gamma-ray fluence may be a better measure of strength of a burst than its peak flux. We discuss how the distribution of the fluence, or any physical quantity related to the peak counts (or flux), can be obtained with proper correction for threshhold effects.

Nicole M. Lloyd-Ronning, Vahe' Petrosian

The distributions of spectral characteristics and their correlations with fluence, peak flux, or duration, are essential in understanding the nature of GRBs. However, the selection effects involved in detecting GRBs can distort these distributions. Here, we discuss how to deal with selection effects involving the peak energy E_p of the GRB nu F_nu spectrum,

D. C. Heggie, M. Giersz, R. Spurzem, K. Takahashi

We review recent progress in computational methods for studying the dynamical evolution of large star clusters. After describing some highlights of a new comparison of different models, including N-body models, we mention in detail recent developments in three codes which allow models with anisotropic distributions of velocity to be studied: (i) a Fokker-Pla

M. Landgraf, E. Gruen

We present the mass distribution of interstellar grains measured in situ by the Galileo and Ulysses spaceprobes as cumulative flux. The derived in situ mass distribution per logarithmic size interval is compared to the distribution determined by fitting extinction measurements. Large grains measured in situ contribute significantly to the overall mass of dus

W. Bednarek

Some aspects of theory of gamma-ray production in blazar type active galaxies are discussed in the context of recent observations.

W. Bednarek

It is proposed that the spectra of so called 'MeV blazars' can be explained in terms of previously developed models of the external comptonization of accretion disk radiation provided that the structure of the inner and outer parts of the accretion disk is different. The electron acceleration is saturated by the inverse Compton losses in the inner ge

Roman Scoccimarro

The standard procedure to generate initial conditions (IC) in numerical simulations is to use the Zel'dovich approximation (ZA). Although the ZA correctly reproduces the linear growing modes of density and velocity perturbations, non-linear growth is inaccurately represented because of the ZA failure to conserve momentum. This implies that it takes time

Matthew G. Baring

Supernova remnants are widely believed to be a principal source of galactic cosmic rays, produced by diffusive shock acceleration in the environs of the remnant's expanding shock. This review discusses recent modelling of how such energetic particles can produce gamma-rays via interactions with the remnants' ambient interstellar medium, specifically

D. C. Heggie

The simulation of rich star clusters presents challenging problems of several kinds, including the design of suitable hardware and software, and numerous theoretical problems in stellar dynamics and stellar physics. Great progress has been made possible in recent years through the widespread use of GRAPE hardware. Simulations are, however, still too small to

F. Combes, T. Wiklind

Some recent results are presented about high redshift molecular absorption lines, namely about chemical abundances of elements, and in particular of water and molecular oxygen. Excitation temperatures of several molecules are found lower than the cosmic background temperature at the corresponding redshift z=0.88582 in PKS1830-211, and interpretations are pro

Martin Pohl, Gottfried Kanbach, Stan D. Hunter, Brian B. Jones

There is active interest in the extent to which unresolved gamma-ray pulsars contribute to the galactic diffuse emission, and whether unresolved gamma-ray pulsars could be responsible for the excess of diffuse galactic emission above 1 GeV which has been observed by EGRET. The diffuse gamma-ray intensity due to unresolved pulsars is directly linked to the nu

I. Garcia-Ruiz, K. Kuijken, J. Dubinski, .

Secondary infall in galaxies could cause the angular momentum of the outer halo to change its orientation. The generation of warps due to this effect is studied using N-body simulations.

Christopher W. Churchill, Jane C. Charlton

Based upon QSO absorption line studies, galaxies at 0.3 < z < 1.0 are seen to have extended gaseous &#34;halos&#34;. When the absorption lines are observed at high resolution, the velocity distribution of the absorbing gas gives clues as to where this gas actually arises in and around the galaxies. Cloud to cloud abundance ratios provide further clues, given

Ue-Li Pen

We propose a strategy to measure the dark matter power spectrum using minimal assumptions about the galaxy distribution and the galaxy-dark matter cross-correlations. We argue that on large scales the central limit theorem generically assures Gaussianity of each smoothed density field, but not coherence. Asymptotically, the only surviving parameters on a giv

Kalle Karu

Let F:X->B be a morphism of varieties in characteristic zero. The problem of semistable reduction of F was stated as a problem in the combinatorics of polyhedral complexes by Abramovich and Karu (alg-geom/9707012). In this paper we solve the combinatorial problem when the relative dimension of F is not bigger than 3.

S. Ferrara, M. Porrati

We consider the maximal central extension of the supertranslation algebra in d=4 and 3, which includes tensor central charges associated to topological defects such as domain walls (membranes) and strings. We show that for all N-extended superalgebras these charges are related to nontrivial configurations on the scalar moduli space. For N=2 theories obtained

H. Garcia-Compean, O. Obregon, J. F. Plebanski, C. Ramirez

For non-abelian non-supersymmetric gauge theories, generic dual theories have been constructed. In these theories the couplings appear inverted. However, they do not possess a Yang-Mills structure but rather are a kind of non-linear sigma model. It is shown that for a topological gravitational model an analog to this duality exists.

S. Gukov, I. R. Klebanov, A. M. Polyakov

An $(n, 1)$ string is a bound state of a D-string and $n$ fundamental strings. It may be described by a D-string with a world volume electric field turned on. As the electric field approaches its critical value, $n$ becomes large. We calculate the 4-point function for transverse oscillations of an $(n, 1)$ string, and the two-point function for massless clos

Robert G. Edwards, Urs M. Heller, Rajamani Narayanan, Robert L. Singleton

We study the spectrum of $H(m)=γ_5 W(-m)$ with $W(m)$ being the Wilson-Dirac operator on the lattice with bare mass equal to $m$. The background gauge fields are generated using the SU(3) Wilson action at $β=5.7$ on an $8^3\times 16$ lattice. We find evidence that the spectrum of $H(m)$ is gapless for $1.02 < m < 2.0$, implying that the physical quark is mas

Andrei Losev, Nikita Nekrasov, Samson Shatashvili

We discuss topological theories, arising from the general $\mathcal{N}=2$ twisted gauge theories. We initiate a program of their study in the Gromov-Witten paradigm. We re-examine the low-energy effective abelian theory in the presence of sources and study the mixing between the various $p$-observables. We present the twisted superfield formalism which makes

Antoine Suarez

Relativistic nonlocality (RNL) is a recently proposed relativistic nonlocal description which unifies relativity of simultaneity and superluminal nonlocality (without superluminal signaling). In this article RNL is applied to experiments with so-called 2 non-before impacts, leading to new rules of calculating the joint probabilities, and predictions conflict

L. Dolan, M. Langham

The partition function of type IIA and B strings on R^6xK3, in the T^4/Z_2 orbifold limit, is explicitly computed as a modular invariant sum over spin strutures required by perturbative unitarity in order to extend the analysis to include type II strings on R^6 x W4, where W4 is associated with the tube metric conformal field theory, given by the degrees of

Amir H. Fatollahi, Kamran Kaviani, Shahrokh Parvizi

Different BPS M-brane configurations including single and two parallel M$p$-branes ($p$= even) and M5-branes are introduced as the classical solutions of the recently proposed Static Matrix Model. Also the long range interactions of two relatively rotated M$p$-branes (one and two angles) and M$p$-brane--anti-M$p$-brane are calculated. The results are in agre

Heng Fan, Xi-Wen Guan

The one-dimensional small-polaron model with open boundary conditions is considered in the framework of the quantum inverse scattering method. The spin model which is equivalent to the small-polaron model is the Heisenberg $XXZ$ spin chain in an external magnetic field. For spin model, the solutions of the reflection equation (RE) and the dual RE are obtaine

M. A. Zudov, R. R. Du, J. A. Simmons, J. L. Reno

We report the detection of the cyclotron(CR) and magneto-plasmon(MPR) resonances near the Fermi surface of high-mobility 2DES, by microwave photoresistance measurements. We observe large amplitude photoresistance oscillations originating from higher-order CR, transitions between non-adjacent Landau levels. Such transitions are drastically enhanced in low mag

Eelco van Kampen

The mass of a cluster of galaxies can be estimated from its lens magnification, which can be determined from the variation in number counts of background galaxies. In order to derive the mass one needs to make assumptions for the lens shear, which is unknown from the variation in number counts alone. Furthermore, one needs to go beyond the weak lensing (line

Matthew G. Baring

The mechanism of diffusive Fermi acceleration at collisionless plasma shock waves is widely invoked in astrophysics to explain the appearance of non-thermal particle populations in a variety of environments, including sites of cosmic ray production, and is observed to operate at several sites in the heliosphere. This review outlines the principal results fro

Victor V. Batyrev

Let $X$ be an arbitrary smooth $n$-dimensional projective variety. It was discovered by Libgober and Wood that the product of the Chern classes $c_1(X)c_{n-1}(X)$ depends only on the Hodge numbers of $X$. This result has been used by Eguchi, Jinzenji and Xiong in their approach to the quantum cohomology of $X$ via a representation of the Virasoro algebra wit

Nobuchika Okada

We present a composite model of quarks with `effective supersymmetry&#39;. The model is based on the gauge group $(SU(2)_S \times SU(2)_M) \times (SU(2)_U \times SU(2)_C \times SU(2)_T) \times SU(5)_{SM}$, where $SU(5)_{SM}$ is the standard model gauge group. In the dynamical supersymmetry breaking sector based on the gauge group $SU(2)_S \times SU(2)_M$, su

Klaus Fabricius, Barry M. McCoy

We study the long time behavior of the zz and xx time dependent autocorrelation function of the spin 1/2 XXZ chain at $T=\infty$ by exact diagonalizations on a chain of 16 sites. We find that the numerical results for the zz correlation are very well fit by the formula $t^{-d}[A+Be^{-γ(t-t_0)}\cos Ω(t-t_0)].$ From this we estimate $d$ as a function of the an

Daijiro Suematsu

A phenomenological neutrino mass matrix is proposed to explain the solar and atmospheric neutrino deficits and to present the neutrino as a candidate of hot dark matter in the $3ν_L+3ν_R$ framework. The realization of mixing angles which can explain the solar and atmospheric neutrino problems is taken as the first criterion in this construction. The differen

Seth Lloyd, Jean-Jacques E. Slotine

Quantum error-correction routines are developed for continuous quantum variables such as position and momentum. The result of such analog quantum error correction is the construction of composite continuous quantum variables that are largely immune to the effects of noise and decoherence.

M. I. Dykman, C. M. Maloney, V. N. Smelyanskiy, M. Silverstein

We analyze the rates of noise-induced transitions between period-two attractors. The model investigated is an underdamped oscillator parametrically driven by a field at nearly twice the oscillator eigenfrequency. The activation energy of the transitions is analyzed as a function of the frequency detuning and field amplitude scaled by the damping and nonlinea

Yihren Wu

Consider a fiber bundle in which the total space, the base space and the fiber are all symplectic manifolds. We study the relations between the quantization of these spaces. In particular, we discuss the geometric quantization of a vector bundle, as oppose to a line bundle, over the base space that recovers the standard geometric quantization of the total sp

Saharon Shelah

This paper is concerned with certain generalizations of meagreness and their combinatorial equivalents. The simplest example, and the one which motivated further study in this area, comes about by considering the following definition: a set X subseteq R is said to be Q-nowhere dense if and only if for every rational q there exists and integer k such that the

Tomek Bartoszyński, Andrzej Rosłanowski, Saharon Shelah

We address ZFC inequalities between some cardinal invariants of the continuum, which turned to be true in spite of strong expectations given by [RoSh:470].

Paul C. Eklof, Saharon Shelah

We show that it is consistent that there is a strongly aleph_1-free aleph_1-coseparable group of cardinality aleph_1 which is not aleph_1-separable.

Ofer Shafir, Saharon Shelah

This paper grew as a continuation of [Sh462] but in the present form it can serve as a motivation for it as well. We deal with the same notions, and use just one simple lemma from there. Originally entangledness was introduced in order to get narrow Boolean algebras and examples of the nonmultiplicativity of c.c-ness. These applications became marginal when

Edson de Faria, Welington de Melo

We prove that any two real-analytic critical circle maps with cubic critical point and the same irrational rotation number of bounded type are $C^{1+α}$ conjugate for some $α>0$.

Edson de Faria, Welington de Melo

We prove that two $C^r$ critical circle maps with the same rotation number of bounded type are $C^{1+α}$ conjugate for some $α>0$ provided their successive renormalizations converge together at an exponential rate in the $C^0$ sense. The number $α$ depends only on the rate of convergence. We also give examples of $C^\infty$ critical circle maps with the same

Dierk Schleicher

We give a new proof that all external rays of the Mandelbrot set at rational angles land, and of the relation between the external angle of such a ray and the dynamics at the landing point. Our proof is different from the original one, given by Douady and Hubbard and refined by Lavaurs, in several ways: it replaces analytic arguments by combinatorial ones; i

Pietro Santorelli

We use three-point QCD sum rules to calculate the form factors governing the rare exclusive decays B \to (K,K^*) \ell^+ \ell^-, B \to (K,K^*) ν\barν. We predict the branching ratios, the invariant mass distributions of the lepton pair for B \to (K,K^*) \ell^+ \ell^-, and the spectra of missing energy for B \to (K,K^*) ν\barν. The forward-backward asymmetry i

P. Zenczykowski

We discuss the applicability of gamma_5-dependent field renormalization as a means of renormalizing away the apparent violation of Hara&#39;s theorem observed in the quark model. It is pointed out that a result totally analogous to the violation of Hara&#39;s theorem is predicted by the quark model also for neutral baryons. For neutral baryons, however, such

H. Matsufuru, S. Hashimoto, K-I. Ishikawa, T. Onogi

We present a quenched calculation of the form factors of the semileptonic weak decay $B \to πl \barν$ with $O(1/m_Q)$ NRQCD heavy quark and Wilson light quark on a $16^3 \times 32$ lattice at $β=5.8$. The form factors are evaluated at six heavy quark masses, in the range of $m_Q \sim 1.5-8$ GeV. $1/m_Q$ dependence of matrix elements are investigated and comp

Richard C. Brower

A quantum Hamiltonian is constructed for SU(3) lattice QCD entirely from color triplet Fermions --- the standard quarks and a new Fermionic ``constituent&#39;&#39; of the gluon we call ``rishons&#39;&#39;. The quarks are represented by Dirac spinors on each site and the gauge fields by rishon-antirishon bilinears on each link which together with the local ga

Marco Spaans

A topological theory for the interactions in Nature is presented. The theory derives from the cyclic properties of the topological manifold Q=2T^3 + 3S^1 x S^2 which has 23 intrinsic degrees of freedom, discrete Z_3 and Z_2 x Z_3 internal groups, an SU(5) gauge group, and an anomalous U(1) symmetry. These properties reproduce the standard model with a stable

Roberto Colistete, Julio C. Fabris, Nelson Pinto-Neto

Minisuperspace models derived from Kaluza-Klein theories and low energy string theory are studied. They are equivalent to one and two minimally coupled scalar fields. The general classical and quantum solutions are obtained. Gaussian superposition of WKB solutions are constructed. Contrarily to what is usually expected, these states are sharply peaked around

M. Howard, C. Godreche

We investigate the persistence probability in the Voter model for dimensions d\geq 2. This is achieved by mapping the Voter model onto a continuum reaction-diffusion system. Using path integral methods, we compute the persistence probability r(q,t), where q is the number of ``opinions&#39;&#39; in the original Voter model. We find r(q,t)\sim exp[-f_2(q)(ln t

Katerina Moloni, Mark Friesen, Shi Li, Victor Souw

The universal behavior of the continuous superconducting (glass) phase transition is studied in a YBa$_2$Cu$_3$O$_{7-δ}$ thin film. A new analysis technique for extracting critical exponents is developed, using current-voltage ($J$-$E$) measurements. The method places narrow limits on the glass scaling exponents, $z_g$ and $ν_g$, as well as the glass transit

Daniel P. Arovas, Francisco Guinea

The phase diagram of doped manganate compounds La_{1-x}A_xMnO_3 (with divalent A) is studied. We analyze an extension of the double exchange model using the Schwinger boson formalism. Earlier work by de Gennes on the existence of a canted phase is reproduced, although this phase is shown to be unstable towards phase separation in a broad regime of physical i

H. C. W. Tso, D. J. W. Geldart, P. Vasilopoulos

Momentum transfer due to Coulomb interaction between two parallel, two-dimensional, narrow, and spatially separated layers, when a current I_{drive} is driven through one layer, is studied in the presence of a perpendicular magnetic field B. The current induced in the drag layer, I_{drag}, is evaluated self-consistently with I_{drive} as a parameter. I_{drag

D. L. Tucker, Y. Hashimoto, R. P. Kirshner, S. D. Landy

A &#34;friends-of-friends&#34; percolation algorithm has been used to extract a catalogue of drho/rho = 80 density enhancements (groups) from the six slices of the Las Campanas Redshift Survey (LCRS). The full catalogue contains 1495 groups and includes 35% of the LCRS galaxy sample. A statistical sample of 394 groups has been derived by culling groups from

T. Joseph W. Lazio, James M. Cordes

We report multifrequency Very Long Baseline Array observations of twelve active galactic nuclei seen toward the Galactic anticenter. All of the sources are at |b| < 10 degrees and seven have |b| < 0.5 degrees. Our VLBA observations can detect an enhancement in the angular broadening of these sources due to an extended H II disk, if the orientation of the H I

T. Joseph W. Lazio, James M. Cordes

We use radio-wave scattering data to constrain the distribution of ionized gas in the outer Galaxy. Like previous models, our model for the H II disk includes parameters for the radial scale length and scale height of the H II, but we allow the H II disk to warp and flare. Our model also includes the Perseus arm. We use a likelihood analysis on 11 extragalac

Eric J. Bakker, David L. Lambert

We have detected circumstellar absorption lines of the $^{12}$CN and $^{13}$CN Violet and Red System in the spectrum of the post-AGB star HD~56126. From a synthetic spectrum analysis, we derive a Doppler broadening parameter of $b=0.51\pm0.04$ km~s$^{-1}$, $^{12}$CN/$^{13}$CN$=38\pm2$, and a lower limit of $2000$ on $^{12}$CN/$^{14}$CN and $^{12}$C$^{14}$N/$

Duiliu-Emanuel Diaconescu, Jaume Gomis

The Matrix description of certain $E_8\times E_8$ heterotic theories on $T^4/Z_2$ is shown to correspond to the world-volume theory of $Spin(32)/Z_2$ heterotic five-branes on the dual $T^4/Z_2\times S^1$.

Gerald B. Cleaver, Alon E. Faraggi

The realistic free fermionic models have had an intriguing success in explaining different properties of the observed particle spectrum. In this paper we discuss in some detail the anomalous U(1) symmetry which exists in these models. We study the properties of the anomalous U(1) in both the more realistic NAHE--based free fermionic models and those in a gen

J. R. Reyes Martinez

Continuing our work hep-th/9609135 where a explicit formula for the two-point functions of the two dimensional Z-invariant Ising model were found. I obtain here different results for the higher correlation functions and several consistency checks are done.

P. J. Rijken, W. L. van Neerven

Misprints in the C_F^2 part of the splitting function ΔP_{gq}^(1) Eq. (3.29) are corrected. Due to a minus sign error between the C_F^2- 1/2 C_A C_F piece and the remaining part of Eq. (A.4), Eq. (3.46) is changed. Finally z_{qq}^{PS,(2)} is know so that we can give the full expression for Δ\bar {\cal C}_{1,q}^{PS} in Eq. (A.1).

Z. Maassarani

A class of recently introduced su(n) `free-fermion&#39; models has recently been used to construct generalized Hubbard models. I derive an algebra defining the `free-fermion&#39; models and give new classes of solutions. I then introduce a conjugation matrix and give a new and simple proof of the corresponding decorated Yang-Baxter equation. This provides th

J. Ranft

The status of some popular models to simulate hadronic and nuclear interactions at Cosmic Ray energies is reviewed. The models predict the rise of all the hadronic and nuclear cross sections with energy and a smooth (logarithmic) rise of average multiplicities, rapidity plateaus and average transverse momenta with the energy. The importance is stressed to pu

Andreas Wacker, Antti-Pekka Jauho

Theories describing electrical transport in semiconductor superlattices can essentially be divided in three disjoint categories: i) transport in a miniband; ii) hopping between Wannier-Stark ladders; and iii) sequential tunneling. We present a quantum transport model, based on nonequilibrium Green functions, which, in the appropriate limits, reproduces the t

H. Anlauf, A. B. Arbuzov, E. A. Kuraev, N. P. Merenkov

We calculate the QED corrections to deep inelastic scattering with tagged photons at HERA in the leading logarithmic approximation. Due to the special experimental setup, two large scales appear in the calculation that lead to two large logarithms of comparable size. The relation of our formalism to the conventional structure function formalism is outlined.

A. Sibirtsev, K. Tsushima, A. W. Thomas

We analyse the $p p \to p \Lambda K^+$ total cross section data which were recently measured by the COSY-11 collaboration at an energy 2~MeV above the reaction threshold. Our analysis suggests that the measurement of the invariant mass spectrum for the $\Lambda K^+$ at energies around 100 MeV above the threshold can provide a new constraint on the theoretica

David W. Hogg, Edwin L. Turner

Flux estimates for faint sources or transients are systematically biased high because there are far more truly faint sources than bright. Corrections which account for this effect are presented as a function of signal-to-noise ratio and the (true) slope of the faint-source number-flux relation. The corrections depend on the source being originally identified

Akikazu Hashimoto

We examine the system where a string stretches between pair of D-branes, and study the bending of the D-brane caused by the tension of the string. If the distance between the pair of D-branes is sent to infinity, the tension of the string stretching between them is strong enough to pull the spike all the way to infinity. We study the shape of these spikes wh

V. B. Kuznetsov, E. K. Sklyanin

Using the n-particle periodic Toda lattice and the relativistic generalization due to Ruijsenaars of the elliptic Calogero-Moser system as examples, we revise the basic properties of the Baecklund transformations (BT&#39;s) from the Hamiltonian point of view. The analogy between BT and Baxter&#39;s quantum Q-operator pointed out by Pasquier and Gaudin is exp

Rob Clifton, David V. Feldman, Michael L. G. Redhead, Alexander Wilce

We investigate a new class of entangled states, which we call &#39;hyperentangled&#39;,that have EPR correlations identical to those in the vacuum state of a relativistic quantum field. We show that whenever hyperentangled states exist in any quantum theory, they are dense in its state space. We also give prescriptions for constructing hyperentangled states

M. Buttiker, H. Thomas

We investigate the time evolution of waves in evanescent media generated by a source within this medium and observed at some distance away from the location of the source. The aim is to find a velocity which describes a causal process and is thus, for a medium with relativistic dispersion, limited by the velocity of light. The wave function consists of a bro

Bengt Nagel

The spectra and generalized eigenfunctions of the hyperbolic and parabolic generators of the standard representation of SU(1,1) in the one-mode boson Hilbert space are derived. The eigenfunctions are given in three different forms, corresponding to the coordinate, photon number, and Fock-Bargmann representations of the state vectors. The possible spectra of

K. Jacobs

It has been shown in recent years that incoherent pumping through multiple atomic levels provides a mechanism for the production of highly anti-bunched light, and that as the number of incoherent steps is increased the light becomes increasingly regular. We show that in a resonance fluorescence situation, a multi-level atom may be multiply coherently driven

C. Quesne

We extend the notion of dually conjugate Hopf (super)algebras to the coloured Hopf (super)algebras ${\cal H}^c$ that we recently introduced. We show that if the standard Hopf (super)algebras ${\cal H}_q$ that are the building blocks of ${\cal H}^c$ have Hopf duals ${\cal H}_q^*$, then the latter may be used to construct coloured Hopf duals ${\cal H}^{c*}$, e

C. Quesne

Coloured Hopf algebras, related to the coloured Yang-Baxter equation, are reviewed, as well as their duals. The special case of coloured quantum universal enveloping algebras provides a coloured extension of Drinfeld and Jimbo formalism. The universal $\cal T$-matrix is then generalized to the coloured context, and shown to lead to an algebraic formulation o

Bo-yu Hou, Wen-li Yang

In this paper, we construct a new Lax operator for the elliptic $A_{n-1}$ Calogero-Moser model with general $n(2\leq n$) from the classical dynamical twisting,in which the corresponding r-matrix is purely numeric (nondynamical one). The nondynamical r-matrix structure of this Lax operator is obtained, which is elliptic $Z_n$-symmetric r-matrix.

S. M. Zoldi, V. Ruban, A. Zenchuk, S. Burtsev

We present a parallel version of the well-known Split-Step Fourier method (SSF) for solving the Nonlinear Schrödinger equation, a mathematical model describing wave packet propagation in fiber optic lines. The algorithm is implemented under both distributed and shared memory programming paradigms on the Silicon Graphics/Cray Research Origin 200. The 1D Fast-

Stoil Donev

This paper summarizes the motivations and results obtained so far in the frame of a particular non-linearization of Classical Electrodynamics, which was called Extended Electrodynamics. The main purpose pursued with this non-linear extension of the classical Maxwell&#39;s equations is to have a reliable field-theoretical approach in describing (3+1) soliton-

Manoj K. Banerjee, John A. Tjon

Using a relativistic Dirac-Brueckner analysis the pion contribution to the ground state energy of nuclear matter is studied. Evidence is presented that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual non-relativistic treatment. The reduction of the pion contribution in nuclear matter

Roberto Emparan

Recent work on solutions to the Born-Infeld theory used to describe D-branes suggests that fundamental strings can be viewed, in a certain limit, as D-branes whose worldvolumes have collapsed to string-like configurations. Here we address the possibility of undoing this collapse, by inducing the string to tunnel to an extended brane configuration. Using semi

W. Lerche, R. Minasian, C. Schweigert, S. Theisen

We present a few remarks on disconnected components of the moduli space of heterotic string compactifications on $T_2$. We show in particular how the eight dimensional CHL heterotic string can be understood in terms of topologically non-trivial $E_8\times E_8$ and $\Spin(32)/Z_2$ vector bundles over the torus, and that the respective moduli spaces coincide.

C. Gomez, R. Hernandez

Lecture notes reviewing most recent developments in string/M/brane theory given by C. G. at the CIME Summer International Center of Mathematics at Cetraro. July 1997.

Leszek Hadasz

We calculate, using zeta function regularization method, semiclassical energy of the Nambu-Goto string supplemented with the boundary, Gauss-Bonnet term in the action and discuss the tachyonic ground state problem.

Taichiro Kugo, Tomohiko Takahashi

The string field theory for unoriented open-closed string mixed system is constructed up to quadratic order based on the joining-splitting type vertices. The gauge invariance with closed string transformation parameter is proved. The infinity cancellation mechanism between disk and projective plane amplitudes plays an essential role for the gauge invariance

A. Abd El-Hady, Alakabha Datta, J. P. Vary

We evaluate the decay constants for the B and $D$ mesons and the form factors for the semileptonic decays of the B meson to $D$ and $D^*$ mesons in a Bethe-Salpeter model. From data we extract $V_{cb}=0.039 \pm 0.002$ from ${\bar B} \to D^* l {\barν} $ and $V_{cb}=0.037 \pm 0.004$ from ${\bar B} \to D l {\barν} $ decays. The form factors are then used to obt

M. L. Mangano

These lectures present a pedagogical introduction to the physics of heavy-flavour production in hadronic collisions. The first lecture gives the theoretical background, with a discussion of leading-order calculations and of the effects of next-to-leading-order corrections. The origin and implications of the large logarithmic corrections appearing at this ord

Roberto Pittau

The present knowledge on four-fermion production in electron-positron collisions is reviewed, with emphasis on W boson physics. Different methods to extract M_W from the data are presented and the role of QCD loop corrections discussed.

Pong Youl Pac

Beyond the standard model, a static potential between quark pairs is obtained phenomenologically (QCD inspired), associated with the range of strong interaction, when the virtual exchange gluon squared momentum transfer has a periodicity for periodic boundary conditions of the quark-pair system enclosed by a constant volume, in the lowest order of the effect

V. B. Svetovoy

In the minimal standard model we discuss stability of the Z-string configuration, which includes the zero mode connected with the broken gauge symmetry. The zero mode induces charge and current on the string and gives backreaction to the string profile changing the region of dynamical stability. For \sin ^2θ_W=0.23 it is found that the string is stabilized f

C. B. Yang, X. Cai

The multiplicity difference correlators between two well-separated bins in high-energy heavy-ion collisions are studied as a means to detect evidence of a first-order quark-hadron phase transition. Analytical expressions for the scaled factorial moments of multiplicity difference distribution are obtained for small bin size $δ$ with mean multiplicity in the

Spin Muon Collaboration

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003<x<0.7$ and $Q^2>$1 GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearl

2 Collaboration

A search for phi radiative decays has been performed using a data sample of about 2.0 million phi decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. From the selected e+ e- -> pi+ pi- gamma events the following results were obtained: B(phi -> f0(980) gamma) < 1x10-4 for destructive and B(phi -> f0(980) gamma) < 7x10-4 for constructive

R. Opher, U. F. Wichoski

The idea that the seed primordial magnetic fields can be explained by the nonminimal coupling between gravitational and electromagnetic fields is discussed. The predicted values of the magnetic field of the spiral galaxies are in agreement with the observations.

U. Bunke

For any compact Lie group G we discuss the relation of the equivariant Reidemeister and analytic torsion of G-manifolds with their G-CW structures.

Rodrigo Arias

Integral expressions are determined for the elastic displacement and stress fields due to stationary or moving dislocation loops in finite samples. These general expressions are valid for anisotropic media as well. Specifically for the stress fields, a line integral representation is found, thus showing rigorously the independence of the stress fields with r

A. P. Jauho

This paper reviews several applications of photonic side-bands, used by Buttiker and Landauer in their theory of traversal time in tunneling [Phys. Rev. Lett. 49, 1739 (1982)], in transport and optics of mesoscopic systems. Topics include generalizations of the transmission theory of transport to time-dependent situations, optics and transport of mesoscopic

András Csordás, Robert Graham, Péter Szépfalusy

The Bogoliubov equations of the quasi-particle excitations in a weakly interacting trapped Bose-condensate are solved in the WKB approximation in an isotropic harmonic trap, determining the discrete quasi-particle energies and wave functions by torus (Bohr-Sommerfeld) quantization of the integrable classical quasi-particle dynamics. The results are used to c

G. Blumberg, M. V. Klein, S-W. Cheong

For La_(1 2/3)Sr_(1/3)NiO_4 -- a commensurately doped Mott-Hubbard system -- charge- and spin-ordering in a stripe phase has been investigated by phononic and magnetic Raman scattering. Formation of a superlattice and an opening of a pseudo-gap in the electron-hole excitation spectra as well as two types of double-spin excitations -- within the antiferromagn