April 1998 arXiv papers — page 16

Jacob J. Christensen, Alan J. Bray

We consider the pattern dynamics of the lamellar phases observed in Rayleigh-Benard convection, as described by the Swift-Hohenberg equation, and in the weak segregation regime of diblock copolymers. Both numerical and analytical investigations show that the dynamical growth of the characteristic length scale in both systems is described by the same growth e

J. L. F. Barbon, A. Pasquinucci

We consider generic MQCD configurations with matter described by semi-infinte D4-branes and softly broken supersymmetry. We show that the matter sector does not introduce supersymmetry breaking parameters so that the most relevant supersymmetry breaking operator at low energies is the gaugino mass term. By studying the run-away properties of these models in

Daniel Braun, Petr A. Braun, Fritz Haake

We present a semiclassical analysis for a dissipative quantum map with an area-nonpreserving classical limit. We show that in the limit of Planck's constant to 0 the trace of an arbitrary natural power of the propagator is dominated by contributions from periodic orbits of the corresponding classical dissipative motion. We derive trace formulae of the Gu

P. Hajicek

The Hamiltonian dynamics of spherically symmetric massive thin shells in the general relativity is studied. Two different constraint dynamical systems representing this dynamics have been described recently; the relation of these two systems is investigated. The symmetry groups of both systems are found. New variables are used, which among other things simpl

Zhan-Ning Hu, Fu-Cho Pu, Yupeng Wang

The hamiltonian with magnetic impurities coupled to the strongly correlated electron system is constructed from $t-J$ model. And it is diagonalized exactly by using the Bethe ansatz method. Our boundary matrices depend on the spins of the electrons. The Kondo problem in this system is discussed in details. The integral equations are derived with complex rapi

P. C. Aichelburg, H. Balasin

We argue that it is possible to assign Bondi as well as ADM four-momentum to the ultrarelativistic limit of the Schwarzschild black hole in agreement to what is expected on physical grounds: The Bondi-momentum is lightlike and equal to the ADM-momentum up to the retarded time when particle and radiation escape to infinity and drops to zero thereafter, leavin

Vadim M. Loktev, Rachel M. Quick, Sergei G. Sharapov

A phase diagram for a quasi-2D metal with variable carrier density has been derived. The phases present are the normal phase, where the order parameter is zero; the pseudogap phase where the absolute value of the order parameter is non-zero but its phase is random, and a superconducting phase with a crossover quasi-2D Berezinskii-Kosterlitz-Thouless (BKT) re

Itzhak Bars

We establish a duality between the free massless relativistic particle in d dimensions, the non-relativistic hydrogen atom (1/r potential) in (d-1) space dimensions, and the harmonic oscillator in (d-2) space dimensions with its mass given as the lightcone momentum of an additional dimension. The duality is in the sense that the classical action of these sys

Paolo Zanardi

The quantum state space $\cal S$ over a $d$-dimensional Hilbert space is represented as a convex subset of a $D-1$-dimensional sphere $S_{D-1}\subset {\bf{R}}^D$, where $D=d^2-1.$ Quantum tranformations (CP-maps) are then associated with the affine transformations of ${\bf{R}}^D,$ and $N\mapsto M$ {\it cloners} induce polynomial mappings. In this geometrical

Anton Kapustin, Savdeep Sethi

We consider supersymmetric gauge theories with impurities in various dimensions. These systems arise in the study of intersecting branes. Unlike conventional gauge theories, the Higgs branch of an impurity theory can have compact directions. For models with eight supercharges, the Higgs branch is a hyperKahler manifold given by the moduli space of solutions

S. P. de Alwis

The assumptions behind the recently conjectured relation between gauge theory and supergravity are elaborated on. It is pointed out that the scaling limit that preserves supergravity solutions, gives the entire DBI action on the gauge theory side, but in the low energy limit the relation between the conformal field theory and Anti-de Sitter supergravity emer

I. Bediaga, R. E. Blanco, C. Göbel, R. Méndez--Galain

A natural procedure is presented to measure the angle $γ$ from the decay $B^{\pm} \to π^{\pm}π^+π^-$. It is based in the Dalitz plot fitting analysis. Neither amplitudes nor strong phases have to be known a priori. We present simulations of this decay computing both statistical and theoretical uncertainties and analyze the experimental feasibility. We found

David A. Meyer

We consider game theory from the perspective of quantum algorithms. Strategies in classical game theory are either pure (deterministic) or mixed (probabilistic). We introduce these basic ideas in the context of a simple example, closely related to the traditional Matching Pennies game. While not every two-person zero-sum finite game has an equilibrium in the

Christopher A. Fuchs, Jeroen van de Graaf

This paper, mostly expository in nature, surveys four measures of distinguishability for quantum-mechanical states. This is done from the point of view of the cryptographer with a particular eye on applications in quantum cryptography. Each of the measures considered is rooted in an analogous classical measure of distinguishability for probability distributi

P. Busch

The convex and metric structures underlying probabilistic physical theories are generally described in terms of base normed vector spaces. According to a recent proposal, the purely geometrical features of these spaces are appropriately represented in terms of the notion of `measure cone' and the `mixing distance' [1], a specification of the novel co

Annie Millet, Marta Sanz-Solé

We prove a characterization of the support of the law of the solution for a stochastic wave equation with two-dimensional space variable, driven by a noise white in time and correlated in space. The result is a consequence of an approximation theorem, in the convergence of probability, for equations obtained by smoothing the random noise. For some particular

Michael Penkava, Pol Vanhaecke

This paper discusses the notion of a deformation quantization for an arbitrary polynomial Poisson algebra A. We examine the Hochschild cohomology group H^3(A) and find that if a deformation of A exists it can be given by bidifferential operators. We then compute an explicit third order deformation quantization of A and show that it comes from a quantized env

R. Coquereaux, A. O. Garcia, R. Trinchero

Using the fact that the algebra M(3,C) of 3 x 3 complex matrices can be taken as a reduced quantum plane, we build a differential calculus Omega(S) on the quantum space S defined by the algebra C^\infty(M) \otimes M(3,C), where M is a space-time manifold. This calculus is covariant under the action and coaction of finite dimensional dual quantum groups. We s

C. Ciliberto, R. Miranda

In this article we address the problem of computing the dimension of the space of plane curves of degree $d$ with $n$ general points of multiplicity $m$. A conjecture of Harbourne and Hirschowitz implies that when $d \geq 3m$, the dimension is equal to the expected dimension given by the Riemann-Roch Theorem. Also, systems for which the dimension is larger t

T. D. Palev

The known Holstein-Primakoff and Dyson realizations of the Lie algebra $sl(n+1), n=1,2,...$ in terms of Bose operators (Okubo S 1975 J. Math. Phys. 16 528) are generalized to the class of the quantum algebras $U_q[sl(n+1)]$ for any $n$. It is shown how the elements of $U_q[sl(n+1)]$ can be expressed via $n$ pairs of Bose creation and annihilation operators.

Teodor Banica

If H is a Hopf algebra whose square of the antipode is the identity, $v\inł(V)\otimes H$ is a corepresentation, and $π:H\toł(W)$ is a representation, then $u=(id\otimesπ)v$ satisfies the equation $(t\otimes id)u^{-1}=((t\otimes id)u)^{-1}$ of the vertex models for subfactors. A universal construction shows that any solution $u$ of this equatio n arises in th

Sergei Ivashkovich, Vsevolod Shevchishin

We prove that the envelope of meromorphy of any imbedded symplectic sphere in $CP^2$ coincides with the whole $CP^2$. As a tool for the proof we use the Gromov theory of pseudo-holomorphic curves. Several results in this subject, such as adjunction formula, smoothness of moduli space in the neighborhood of a cusp-curve are improved. We introduce a natural ho

B. C. Ngo

We give a geometric interpretation of the base change homomorphism between the Hecke algebra of GL(n) for an unramified extension of local fields of positive characteristic. For this, we use some results of Ginzburg, Mirkovic and Vilonen related to the geometric Satake isomorphism. We give new proof for these results in the positive characteristic case. By u

Michael Faux

A topological fact about eleven dimensions is used to motivate a potential new duality in M-theory. We complete the discussion of consistent limits of M-theory raised in a previous paper to include gravitational anomaly cancelation and four-form flux quantization in the context of the $M^{10}\times S^1/Z_2$ compactifications. A suprise is found: If one inclu

M. A. Doncheski, R. W. Robinett

Using recent collider data, especially on the hadronic width the Z0, we exclude axigluons in the currently allowed low-mass window, namely axigluons in the mass range 50 GeV < M_A < 120 GeV. Combined with hadron collider data from di-jet production, axigluons with masses below roughly 1 TeV are now completely excluded.

J. A. Grifols

I review the constraints on the mass of gravitinos that follow from considerations on energy loss in stars and from Big Bang Nucleosynthesis arguments.

P. Aurenche, F. Gelis, R. Kobes, H. Zaraket

In this paper, we extend the study of bremsstrahlung photon production in a quark-gluon plasma to the cases of soft static photons and hard real photons. The general framework of this study is the effective perturbative expansion based on the resummation of hard thermal loops. Despite the fact that bremsstrahlung only comes at two loops, we find that in both

M. Bordag, B. Geyer, G. L. Klimchitskaya, V. M. Mostepanenko

The Casimir force is calculated in the configuration of a spherical lens and a disc of finite radius covered by $Cu$ and $Au$ thin layers which was used in a recent experiment. The correction to the Casimir force due to finiteness of the disc radius is shown to be negligible. Also the corrections are discussed due to the finite conductivity, large-scale and

P. Pennanen, A. M. Green, C. Michael

The full spatial distribution of the color fields of two and four static quarks is measured in lattice SU(2) field theory at separations up to 1 fm at beta=2.4. The four-quark case is equivalent to a qbar q qbar q system in SU(2) and is relevant to meson-meson interactions. By subtracting two-body flux tubes from the four-quark distribution we isolate the fl

A. M. Green, P. Pennanen

A potential model for four interacting quarks is constructed in SU(2) from six basis states -- the three partitions into quark pairs, where the gluon field is either in its ground state or first excited state. With four independent parameters to describe the interactions connecting these basis states, it is possible to fit 100 pieces of data -- the ground an

C. J. Fewster

We consider 2-dimensional cylinder spacetimes whose metrics differ from the flat Minkowskian metric within a compact region. By choice of time orientation, these spacetimes may be regarded as either globally hyperbolic timelike cylinders or nonglobally hyperbolic spacelike cylinders. For generic metrics in our class, we classify all possible candidate quantu

C. J. Fewster

We prove a novel unique continuation result for weak bisolutions to the massive Klein-Gordon equation on a 2-dimensional cylinder M. Namely, if such a bisolution vanishes in a neighbourhood of a `sufficiently large&#39; portion of a 2-dimensional surface lying parallel to the diagonal in the product manifold of M with itself, then it is (globally) translatio

B. Mashhoon, F. Gronwald, F. W. Hehl, D. S. Theiss

The difference in the proper azimuthal periods of revolution of two standard clocks in direct and retrograde orbits about a central rotating mass is proportional to J/Mc^2, where J and M are, respectively, the proper angular momentum and mass of the source. In connection with this gravitomagnetic clock effect, we explore the possibility of using spaceborne s

D. A. Garanin

The static transverse and longitudinal correlation functions (CF) of a 3-dimensional ferromagnet are calculated for the exactly solvable anisotropic spherical model (ASM) determined as the limit D \to \infty of the classical D-component vector model. The results are nonequivalent to those for the standard spherical model of Berlin and Kac even in the isotrop

D. A. Garanin

The temperature-induced second-order phase transition from Bloch to linear (Ising-like) domain walls in uniaxial ferromagnets is investigated for the model of D-component classical spin vectors in the limit D \to \infty. This exactly soluble model is equivalent to the standard spherical model in the homogeneous case, but deviates from it and is free from unp

P. Kostic, Y. Okada, Z. Schlesinger, J. W. Reiner

The reflectivity of the itinerant ferromagnet SrRuO_3 has been measured between 50 and 25,000 cm-1 at temperatures ranging from 40 to 300 K, and used to obtain conductivity, scattering rate, and effective mass as a function of frequency and temperature. We find that at low temperatures the conductivity falls unusually slowly as a function of frequency (propo

M. Poza, E. Bascones, J. G. Rodrigo, N. Agrait

Nanowires of lead between macroscopic electrodes are produced by means of an STM. Magnetic fields may destroy the superconductivity in the electrodes, while the wire remains in the superconducting state. The properties of the resulting microscopic Josephson junctions are investigated.

Giancarlo Franzese, Antonio Coniglio

We have studied the Potts spin glass with 2-state Ising spins and s-state Potts variables using a cluster Monte Carlo dynamics. The model recovers the +- J Ising spin glass (SG) for s=1 and exhibits for all s a SG transition at T_{SG}(s) and a percolation transition at higher temperature T_p(s). We have shown that for all values of $s\neq 1$ at T_p(s) there

Dario Alfe`, Michael J. Gillan

First principles electronic structure calculations, based upon density functional theory within the generalized gradient approximation and ultra-soft Vanderbilt pseudopotentials, have been used to simulate a liquid alloy of iron and sulfur at Earth&#39;s core conditions. We have used a sulfur concentration of $\approx 12 % $wt, in line with the maximum recen

K Walasek, K Lukierska- Walasek, L De Cesare, I Rabuffo

The classical transverse field Ising spin- glass model with short-range interactions is investigated beyond the mean- field approximation for a real d- dimensional lattice. We use an appropriate nontrivial modification of the Bethe- Peierls method recently formulated for the Ising spin- glass. The zero- temperature critical value of the transverse field and

Dario Alfe`, Stefano de Gironcoli, Stefano Baroni

We report on a first-principles study of the structure of O/Rh(001) at half a monolayer of oxygen coverage, performed using density-functional theory. We find that oxygen atoms sit at the center of the black squares of a chess-board, $c(2\times 2)$, pattern. This structure is unstable against a rhomboid distortion of the black squares, which shortens the dis

Volker Pasler, Peter Schweiss, Christoph Meingast, Bernhard Obst

The strong coupling of superconductivity to the orthorhombic distortion in YBa2Cu3O7-d makes possible an analysis of the superconducting fluctuations without the necessity of subtracting any background. The present high-resolution capacitance dilatometry data unambiguously demonstrate the existence of critical, instead of Gaussian, fluctuations over a wide t

G. Goldoni, F. Rossi, E. Molinari

We propose a new type of hybrid systems formed by conventional semiconductor nanostructures with the addition of remote insulating layers, where the electron-hole interaction is enhanced by combining quantum and dielectric confinement over different length scales. Due to the polarization charges induced by the dielectric mismatch at the semiconductor/insulat

S. Caspi, E. Ben-Jacob

A novel approach to protein folding dynamics is presented. We suggest that folding of protein may be mediated via interaction with solitons which propagate along the molecular chain. A simple toy model is presented in which a Sine-Gordon field interact with another field corresponding to the conformation angles of the protein. We demonstrate how a soliton ca

G. R. Schreiber, O. C. Martin

We investigate the statistical properties of cut sizes generated by heuristic algorithms which solve approximately the graph bisection problem. On an ensemble of sparse random graphs, we find empirically that the distribution of the cut sizes found by ``local&#39;&#39; algorithms becomes peaked as the number of vertices in the graphs becomes large. Evidence

Gyorgy Szabo, Gyorgy Kadar

Using zero temperature Monte Carlo simulations we have studied the magnetic hysteresis in a three-dimensional Ising model with nearest neighbor exchange and dipolar interaction. The average magnetization of spins located inside a sphere on a cubic lattice is determined as a function of magnetic field varied periodically. The simulations have justified the ap

E. Brezin, S. Hikami

In an earlier work we had considered a Gaussian ensemble of random matrices in the presence of a given external matrix source. The measure is no longer unitary invariant and the usual techniques based on orthogonal polynomials, or on the Coulomb gas representation, are not available. Nevertheless the n-point correlation functions are still given in terms of

E. Brezin, S. Hikami

We consider a Hamiltonian $ H = H_0+ V $, in which $ H_0$ is a given non-random Hermitian matrix,and $V$ is an $N \times N$ Hermitian random matrix with a Gaussian probability distribution.We had shown before that Dyson&#39;s universality of the short-range correlations between energy levels holds at generic points of the spectrum independently of $H_{0}$. W

Eurico Covas, Reza Tavakol, Peter Ashwin, Andrew Tworkowski

Employing some recent results in dynamics of systems with invariant subspaces we find evidence in both truncated and full axisymmetric mean-field dynamo models of a recently discovered type of intermittency, referred to as in-out intermittency. This is a generalised form of on-off intermittency that can occur in systems that are not skew products. As far as

Moshe Elitzur

Profile comparison of the Stokes parameters $V$ and $I$ is a powerful tool for maser data analysis, providing the first direct methods for unambiguous determination of (1) the maser saturation stage, (2) the amplification optical depth and intrinsic Doppler width of unsaturated masers, and (3) the comparative magnitudes of Zeeman splitting and Doppler linewi

Frank C. van den Bosch, Eric Emsellem

We present circumstantial evidence that the central region of the edge-on S0 galaxy NGC 4570, which harbors a 150 pc scale nuclear disc in addition to its main outer disc, has been shaped under the influence of a small (approx. 500pc) bar. This is based on the finding of two edge-on rings, whose locations are consistent with the Inner Lindblad and Ultra Harm

Stephen Levine, Linda Sparke

Two dimensional realizations of self-consistent models for the ``perfect elliptic disks&#39;&#39; were tested for global stability by gravitational N-body integration. The family of perfect elliptic disk potentials have two isolating integrals; time independent distribution functions f(E,I_2) which self-consistently reproduce the density distribution can be

R. Srianand, P. Petitjean

We present a detailed analysis of a high resolution spectrum of the damped Ly$α$ system at $z_{\rm abs}$~=~2.8112toward PKS~0528-250. The absorption redshift is slightly larger than the emission redshift of the quasar. We estimate the column density of H$_2$ molecules $N$(H$_2$)~$\sim$~6$\times$10$^{16}$~cm$^{-2}$ and the fractional abundance of H$_2$, $f$~=

William H. Kinney, Scott Dodelson, Edward W. Kolb

The upcoming satellite missions MAP and Planck will measure the spectrum of fluctuations in the Cosmic Microwave Background with unprecedented accuracy. We discuss the prospect of using these observations to distinguish among proposed models of inflationary cosmology.

M. Serote Roos, C. Boisson, M. Joly, M. J. Ward

Recent observations supported by theoretical models have lead to the view that giant and supergiant stars are over abundant, and/or a high metallicity component may be present, in the stellar populations at the centres of active galaxies. Here we attempt to quantify these effects by observing the strengths of the stellar absorption lines of Mg~b, NaI, CaII t

Liliya L. R. Williams, Mike Irwin

We detect a positive angular correlation between bright, high-redshift QSOs and foreground galaxies. The QSOs are taken from the optically selected LBQS Catalogue, while the galaxies are from the APM Survey. The correlation amplitude is about a few percent on angular scales of over a degree. It is a function of QSO redshift and apparent magnitude, in a way e

H. Kubo, T. Takahashi, G. Madejski, M. Tashiro

We present data for 18 blazars observed with ASCA, half of which were also observed contemporaneously with EGRET as parts of multi-wavelength campaigns. The observations show a clear difference in the spectra between three subclasses of blazars, namely the High-energy peaked BL Lac objects (HBLs), Low-energy peaked BL Lac objects (LBLs), and quasar-hosted bl

J S Clark, I A Steele, R P Fender

We present the first radio observations of a sample of 13 optically and IR bright southern hemisphere classical Be stars made from the Australian Telescope Compact Array at 3.5cm and 6.3cm simultaneously. One star, delta Cen was detected at 3.5cm and a second, mu Cen was also thought to have been detected; further observations of this source are required to

Kohji Tomisaka

The importance of the interstellar magnetic field is studied in relation to the evolutions of superbubbles with a three-dimensional (3D) numerical magnetohydrodynamical (MHD) simulation. A superbubble is a large supernova remnant driven by sequential supernova explosions in an OB association. Its evolution is affected by the density stratification in the gal

S. Andreon

We find that the bright part (M_B<-18.5 mag) of luminosity function of each Hubble type has the same shape in three poor clusters (Virgo, Fornax and Centaurus) and in two rich clusters (Coma and Cl0939+4713). The fact that these type-dependent luminosity functions are invariant in shape from poor to rich environments gives support to the hypothesis that they

Katrina M. Sealey, Michael. J. Drinkwater, John K. Webb, Brian J. Boyle

The Hubble Deep Field-South (HDF-S) was chosen to have a QSO (RA 22:33:37.6 Dec -60:33:29 J2000 and B=17.5) in the field to allow for studies of absorption systems intersecting the sight line to the QSO. To assist in the planning of HDF-S observations we present here a ground-based spectrum of the QSO. We measure a redshift of z=2.24 for the QSO and find ass

P. Tozzi, A. Cavaliere, N. Menci

The X-ray emission from clusters of galaxies is one of the best observational probe to investigate the distribution of dark matter at intermediate and high redshifts. Since the disposition of the intracluster plasma (ICP) responsible of the emission is crucial to link X-ray properties to the global properties of the dark matter halos, we propose a semi--anal

G. Aldazabal, A. Font, L. E. Ibanez, G. Violero

We study different aspects of the construction of D=4, N=1 type IIB orientifolds based on toroidal Z_N and Z_M x Z_N, D=4 orbifolds. We find that tadpole cancellation conditions are in general more constraining than in six dimensions and that the standard Gimon-Polchinski orientifold projection leads to the impossibility of tadpole cancellations in a number

D. Kharzeev, R. D. Pisarski, M. H. G. Tytgat

We suggest that for QCD in the limit of a large number of colors, N, the axial U(1) symmetry of massless quarks is effectively restored at the deconfining=chiral phase transition. If the deconfining transition is of second order, then the chiral transition is weakly first order. In this case, metastable states in which parity is spontaneously broken appear a

Lev I. Deych, D. Zaslavsky, A. A. Lisyansky

By means of Monte Carlo simulations we show that there are two qualitatively different modes of localization of classical waves in 1-{\em D} random periodic-on-average systems. States from pass bands and band edges of the underlying band structure demonstrate single parameter scaling with universal behavior. States from the interior of the band gaps do not h

B. Pioline

Exact non-perturbative results have been conjectured for R^4 couplings in type II maximally supersymmetric string theory. Strong evidence has already been obtained, but contributions of cusp forms, invisible in perturbation theory, have remained an open possibility. In this note, we use the D=8 N=2 superfield formalism of Berkovits to prove that supersymmetr

E. S. Swanson, A. P. Szczepaniak

Hybrid meson energies are calculated in the static quark limit with the Dynamical Quark Model (DQM). In the DQM, transverse gluons are represented as effective constituents with a dynamically generated mass. Hybrid masses are determined within the Tamm-Dancoff approximation for the resulting relativistic Salpeter equation. Although the general features of th

Ricardo Amorim, Nelson R. F. Braga, Marc Henneaux

We compute the anomalous divergence of currents associated with global transformations in the antifield formalism, by introducing compensating fields that gauge these transformations. We consider the explicit case of the global axial current in QCD but the method applies to any global transformation of the fields.

Wojciech Slomczynski, Jaroslaw Kwapien, Karol Zyczkowski

We discuss the properties of invariant measures corresponding to iterated function systems (IFSs) with place-dependent probabilities and compute their Renyi entropies, generalized dimensions, and multifractal spectra. It is shown that with certain dynamical systems one can associate the corresponding IFSs in such a way that their generalized entropies are eq

J. Bicak, V. Pravda

Scalar curvature invariants are studied in type N solutions of vacuum Einstein&#39;s equations with in general non-vanishing cosmological constant Lambda. Zero-order invariants which include only the metric and Weyl (Riemann) tensor either vanish, or are constants depending on Lambda. Even all higher-order invariants containing covariant derivatives of the W

Hitoshi Murayama

I argue that it would be crucial to have as many channels as possible to understand the physics of electroweak symmetry breaking (EWSB) in next-generation collider experiments. A historic example of the parity violation and the $V-A$ interaction is used to make this point. An e^- e^- option offers us a new channel in this respect. The usefulness of this chan

C. Castellani, C. Di Castro, M. Grilli

We discuss the effects of a quantum critical point located nearby optimum doping and related to local charge segregation (stripe phase). The fluctuations in the critical region produce at the same time a strong pairing mechanism and a non-Fermi liquid behavior in the normal phase above the superconducting critical temperature. Superconductivity is a stabiliz

A. B. Arbuzov, O. Krehl, E. A. Kuraev, E. N. Magar

Radiative muon decay in the kinematics similar to the neutrinoless decay $μ\to eγ$ is considered. Radiative corrections due to 1-loop virtual photons and emission of additional soft or hard photons are taken into account. Analytical expressions and numerical estimations are presented.

D. V. Antonov

An effective string theory emerging from the bilocal approximation to the Method of Vacuum Correlators in gluodynamics is shown to be well described by the 4D theory of the massive Abelian Kalb-Ramond field interacting with the string, which is known to be the low-energy limit of the Universal Confining String Theory. The mass of the Kalb-Ramond field in thi

Sandra Savaglio

The Hubble Deep Field South (HDFS) has been recently selected and the observations are planned for October 1998. We present a high resolution (FWHM $\simeq 14$ \kms) spectrum of the quasar J2233--606 ($z_{em}\simeq2.22$) which is located 5.1 arcmin East of the HDFS. The spectrum obtained with the New Technology Telescope redward of the Lyman--$α$ emission li

Steffen Schäfer, Peter Schuck

An approach for particle-hole correlation functions, based on the so-called SCRPA, is developed. This leads to a fully self-consistent RPA-like theory which satisfies the $f$-sum rule and several other theorems. As a first step, a simpler self-consistent approach, the renormalized RPA, is solved numerically in the one-dimensional Hubbard model. The charge an

Andy Wilkins

The first massive level of closed bosonic string theory is studied. Free-field equations are derived by imposing Weyl invariance on the world sheet. A two-parameter solution to the equation of motion and constraints is found in two dimensions with a flat linear-dilaton background. One-to-one tachyon scattering is studied in this background. The results suppo

Craig A. Tracy, Harold Widom

The usual formulas for the correlation functions in orthogonal and symplectic matrix models express them as quaternion determinants. From this representation one can deduce formulas for spacing probabilities in terms of Fredholm determinants of matrix-valued kernels. The derivations of the various formulas are somewhat involved. In this article we present a

E. Bergshoeff, P. K. Townsend

A version of the kappa-symmetric super D-p-brane action is presented in which the tension is a dynamical variable, equal to the flux of a p-form worldvolume gauge field. The Lagrangian is shown to be invariant under all (super)isometries of the background for appropriate transformations of the worldvolume gauge fields, which determine the central charges in

John R. Klauder

Canonical quantization may be approached from several different starting points. The usual approaches involve promotion of c-numbers to q-numbers, or path integral constructs, each of which generally succeeds only in Cartesian coordinates. All quantization schemes that lead to Hilbert space vectors and Weyl operators---even those that eschew Cartesian coordi

C. Cabrillo, J. L. Roldan, P. Garcia-Fernandez

We study the quantum noise in the harmonic mode of a singly resonant frequency doubler simultaneously driven in both modes. This simple extension of the frequency doubler greatly improves its performance as a bright squeezed light source. Specifically, for parameters corresponding to reported experiments, 80 % of noise suppression is easily achieved, the pha

M. Buzzacchi, E. Del Giudice, G. Preparata

The widening phenomenology of Single Bubble Sonoluminescence (SBSL) is shown to be in good agreement with a new approach to condensed matter, based on the QED coherent interactions. Some remarkable properties of SBSL are shown to emerge from the electromagnetic release of part of the latent heat of the water&#39;s vapour-liquid phase transition occurring at

Arun Kumar Pati

We propose the Aharonov-Casher (AC) effect for four entangled spin-half particles carrying magnetic moments in the presence of impenetrable line charge. The four particle state undergoes AC phase shift in two causually disconnected region which can show up in the correlations between different spin states of distant particles. This correlation can violate Be

Daniel Poitras, Ludvik Martinu

Reliable control of the deposition process of optical films and coatings frequently requires monitoring of the refractive index profile throughout the layer. In the present work a simple in situ approach is proposed which uses a WKBJ matrix representation of the optical transfer function of a single thin film on a substrate. Mathematical expressions are deve

Stanislaw D. Glazek

This paper describes a network of teachers and students who form a living system of education at all levels and achieve high standards. The key process of the network is the process of effective learning by inquiry. Physics is distinguished among sciences as the most transparent source of understanding what it means to learn effectively by inquiry. We sugges

J. Kwapien, S. Drozdz, L. C. Liu, A. A. Ioannides

Simultaneous estimates of the activity in the left and right auditory cortex of five normal human subjects were extracted from Multichannel Magnetoencephalography recordings. Left, right and binaural stimulation were used, in separate runs, for each subject. The resulting time-series of left and right auditory cortex activity were analysed using the concept

M. Blaauboer, D. Lenstra, A. Lodder

We theoretically study reflection of light by a phase-conjugating mirror preceded by a partially reflecting normal mirror. The presence of a suitably chosen normal mirror in front of the phase conjugator is found to greatly enhance the total phase-conjugate reflected power, even up to an order of magnitude. Required conditions are that the phase-conjugating

C. R. Brune, W. H. Geist, H. J. Karwowski, E. J. Ludwig

We present measurements of the analyzing powers Ay and iT11 for proton-deuteron scattering at Ecm=432 keV. Calculations using a realistic nucleon-nucleon potential (Argonne V18) are found to underpredict both analyzing powers by 40. The inclusion of the Urbana three-nucleon interaction does not significantly modify the calculated analyzing powers. Due to its

R. Casalbuoni

In this paper we apply a recently proposed algebraic theory of integration to projective group algebras. These structures have received some attention in connection with the compactification of the $M$ theory on noncommutative tori. This turns out to be an interesting field of applications, since the space $\hat G$ of the equivalence classes of the vector un

John McCuan

In this paper we consider a ``flow&#39;&#39; of nonparametric solutions of the volume constrained Plateau problem with respect to a convex planar curve. Existence and regularity is obtained from standard elliptic theory, and convexity results for small volumes are obtained as an immediate consequence. Finally, the regularity is applied to show a strong stabi

Jonathan David Farley

The fixed point property for finite posets of width 3 and 4 is studied in terms of forbidden retracts. The ranked forbidden retracts for width 3 and 4 are determined explicitly. The ranked forbidden retracts for the width 3 case that are linearly indecomposable are examined to see which are minimal automorphic. Part of a problem of Niederle from 1989 is thus

Roberto G. Ferretti

The Schmidt Subspace Theorem affirms that the solutions of some particular system of diophantine approximations in projective spaces accumulates on a finite number of proper linear subspaces. Given a subvariety $X$ of a projective space $P^n$, does there exists a system of diophantine approximations on $P^n$ whose solutions are Zariski dense in $P^n$, but li

Itai Benjamini, Russell Lyons, Oded Schramm

We show that on a Cayley graph of a nonamenable group, almost surely the infinite clusters of Bernoulli percolation are transient for simple random walk, that simple random walk on these clusters has positive speed, and that these clusters admit bounded harmonic functions. A principal new finding on which these results are based is that such clusters admit i

Sergei Ivashkovich

We construct a (non Kähler) compact complex 3-dimensional manifold $X$ having two following properties: 1) for any domain $D$ in $C^2$ every meromorphic map $f$ from this domain into $X$ extends to a meromorphic map from the envelope of meromorphy $\hat D$ of $D$ into $X$; 2) but there exist a meromorphic map $F$ from a punctured ball $B_*$ in $C^3$ into $X$

Sergei Ivashkovich

We consider a complex Plateau problem for strongly pseudoconvex contours in non Kähler manifolds. A positive solution in the case of manifolds carrying a pluriclosed Hermitian metric forms is given. For the general case we propose a conjecture.

Sergei Ivashkovich

We give several unequivalent notions of convergency of meromorphic functions and more generally meromorphic mappings (strong, weak, $Γ$-convergency and some others). Relations between them are investigated. A version of Rouche theorem for the strongly converging sequences of meromorphic mappings is given. Further we investigate the sets of normality of famil

P. P. Kulish, A. I. Mudrov

The universal $R$-matrix for a class of esoteric (non-standard) quantum groups ${\cal U}_q(gl(2N+1))$ is constructed as a twisting of the universal $R$-matrix ${\cal R}_S$ of the Drinfeld-Jimbo quantum algebras. The main part of the twisting element ${\cal F}$ is chosen to be the canonical element of appropriate pair of separated Hopf subalgebras (quantized

Victor Ginzburg

Given a complex projective algebraic variety, write H(X) for its cohomology with complex coefficients and IH(X) for its Intersection cohomology. We first show that, under some fairly general conditions, the canonical map H(X)\to IH(X) is injective. Now let Gr = G((z))/G[[z]] be the loop Grassmannian for a complex semisimple group G, and let X be the closure

José Gaite

We present the thermodynamic Bethe ansatz as a way to factorize the partition function of a 2d field theory, in particular, a conformal field theory and we compare it with another approach to factorization due to K. Schoutens which consists of diagonalizing matrix recursion relations between the partition functions at consecutive levels. We prove that both a

S. Dalley

In the light-cone Fock state expansion of gauge theories, the influence of non-valence states may be significant in precision non-perturbative calculations. In two-dimensional gauge theories, it is shown how these states modify the behaviour of the light-cone wavefunction in significant ways relative to endemic choices of variational ansatz. Similar effects