August 1994 arXiv papers — page 2

F. M. Walter, S. J. Wolk, N. R. Adams

We report the discovery of a new catacysmic variable system, RXJ051541+0104.6. The optical spectrum has a blue continuum with superposed H~I and He~I and II emission lines. The soft X-ray spectrum is well fit with a 50~eV black body. The X-ray and optical data are suggestive of an AM~Herculis system. The X-ray light curve shows extreme variability on timesca

M. Girardi, A. Biviano, G. Giuricin, F. Mardirossian

We analyze the density profiles and virial radii for a sample of 90 nearby clusters, using galaxies with available redshifts and positions. Each cluster has at least 20 redshifts measured within an Abell radius, and all the results come from galaxy sets of at least 20 members. Most of the density profiles of our clusters are well fitted by hydrostatic-isothe

B. S. Sathyaprakash, V. Sahni, D. Munshi, D. Pogosyan

We study the development of gravitational instability in the strongly non-linear regime. For this purpose we use a number of statistical indicators such as filamentary statistics, spectrum of overdense/underdense regions and the void probability function, each of which probes a particular aspect of gravitational clustering. We use these statistical indicator

P. A. Thomas, R. L. Webster, M. J. Drinkwater

There is controversy about the measurement of statistical associations between bright quasars and faint, presumably foreground galaxies. We look at the distribution of galaxies around an unbiased sample of 63 bright, moderate redshift quasars using a new statistic based on the separation of the quasar and its nearest neighbour galaxy. We find a significant e

Robert W. Berger

Three notions of associated prime ideals, which are equivalent in the noetherian case but differ in the non notherian case, are discussed. Examples illustrate the scope of the notions.

Hanying Guo, Jianming Li, 7 pages, Latex

By means of the non-commutative differential geometry, we construct an $SU(2)$ generalized gauge field model. It is of $SU(2) \times \pi_4(SU(2))$ gauge invariance. We show that this model not only includes the Higgs field automatically on the equal footing with ordinary Yang-Mills gauge potentials but also is stable against quantum correlation.

Lev Vaidman

Weak measurement is a standard measuring procedure with two changes: it is performed on pre- and post-selected quantum systems and the coupling to the measuring device is weakened. The outcomes of weak measurements, ``weak values'' are very different for the eigenvalues of the measured operators. The weak values yield novel rich structure of the quan

N. Auerbach, J. D. Bowman, V. Spevak

We discuss the implications of a doorway state model for parity mixing in compound nuclear states. We argue that in order to explain the tendency of parity violating asymmetries measured in $^{233}$Th to have a common sign, doorways that contribute to parity mixing must be found in the same energy neighbourhood of the measured resonance. The mechanism of par

K. Intriligator, N. Seiberg

We exhibit $N=1$ supersymmetric field theories in confining, Coulomb and Higgs phases. The superpotential and the gauge kinetic terms are holomorphic and can be determined exactly in the various phases. The Coulomb phase generically has points with massless monopoles. When they condense, the theory undergoes a phase transition to a confining phase. When ther

Yakir Aharonov, Jeeva Anandan, Lev Vaidman

Protective measurements, which we have introduced recently, allow to measure properties of the state of a single quantum system and even the Schrödinger wave itself. These measurements require a protection, sometimes due to an additional procedure and sometimes due to the potential of the system itself. The analysis of the protective measurements is presente

Hanying Guo, Jianming Li, Ke Wu

Based upon a first principle, the generalized gauge principle, we construct a general model with $G_L\times G'_R \times Z_2$ gauge symmetry, where $Z_2=π_4(G_L)$ is the fourth homotopy group of the gauge group $G_L$, by means of the non-commutative differential geometry and reformulate the Weinberg-Salam model and the standard model with the Higgs field

Hanying Guo, Jianming Li, Ke Wu, 10 pages

In terms of non-commutative geometry, we show that the $σ$--model can be built up by the gauge theory on discrete group $Z_2$. We introduce a constraint in the gauge theory, which lead to the constraint imposed on linear $σ$ model to get nonlinear $σ$ model .

Bin Chen, Han-Ying Guo, Hong-Bo Teng

We construct a gauge field model based on $SU(2)_L\times SU(2)_R\times U(1)_Y \times π_4(SU(2)_L\times SU(2)_R\times U(1)_Y) $ from the principle that both the original gauge group $G_{YM}$ and the discrete group $π_4(G_{YM})$ should be taken as gauge groups in the sense of non-commutative geometry. We show that the Yukawa coupling and the Higgs mechanism ap

P. J. Forrester

Some ground state static correlation functions for the $1/r^2$ exchange $t-J$ model of Kuramoto and Yokoyama are calculated exactly. The correlations calcualted are the pair distribution functions between two down spins, a down spin and a hole, and two holes, and the one body density matrix (equal time retarded Green's function) for holes

E. H. Rezayi, F. D. M. Haldane

We study the Laughlin wave function on the cylinder. We find it only describes an incompressible fluid when the two lengths of the cylinder are comparable. As the radius is made smaller at fixed area, we observe a continuous transition to the charge density wave Tao-Thouless state. We also present some exact properties of the wave function in its polynomial

Xiang-Ping Wu, Jinlin Han

The theory predicts that the effect of gravitational lensing by the matter associated with clusters of galaxies can magnify background sources, leading to an enhancement of source number density around foreground clusters of galaxies. We conduct a search for the associations of distant radio-bright quasars with Abell clusters using the 1-Jy and 2-Jy all-sky

Mary K. Gaillard

It is shown that the one-loop quadratic divergences of standard supergravity can be regulated by the introduction of heavy Pauli-Villars fields belonging to chiral and abelian gauge multiplets. The resulting one-loop correction can be interpreted as a renormalization of the Kähler potential. Regularization of the dilaton couplings to the Yang-Mills sector re

Glennys R. Farrar

Gluino and lightest neutralino masses are naturally less than a few GeV if dimension-3 susy-breaking operators are absent from the low energy theory. In this case gaugino masses come from loops and are calculable in terms of known particle masses and two mass parameters, $μ$ and $\tilde{m}$. The phenomenology of such a scenario is discussed.

Valeri Dvoeglazov

The main goal of the paper is to study the origins of a contradiction between the Weinberg theorem B-A=λand the `longitudinality' of an antisymmetric tensor field (and of a Weinberg field which is equivalent to it), transformed on the (1,0)\oplus (0,1) Lorentz group representation. On the basis of analysis of dynamical invariants in the Fock space situat

D. S. Goldwirth, J. Katz

This comment contains a suggestion for a slight modification of Israel's covariant formulation of junction conditions between two spacetimes, placing both sides on equal footing with normals having uniquely defined orientations. The signs of mass energy densities in thin shells at the junction depend not only on the orientations of the normals and it is

A. O. Barut, J. R. Zeni, A. J. Laufer

In this article we extend our previous results for the orthogonal group, $SO(2,4)$, to its homomorphic group $SU(2,2)$. Here we present a closed, finite formula for the exponential of a $4\times 4$ traceless matrix, which can be viewed as the generator (Lie algebra elements) of the $SL(4,C)$ group. We apply this result to the $SU(2,2)$ group, which Lie algeb

Jorma Louko

The Chern-Simons functional $S_{\rm CS}$ is an exact solution to the Ashtekar-Hamilton-Jacobi equation of general relativity with a nonzero cosmological constant. In this paper we consider $S_{\rm CS}$ in Bianchi type IX cosmology with $S^3$ spatial surfaces. We show that among the classical solutions generated by~$S_{\rm CS}$, there is a two-parameter famil

Michael Boshernitzan, G. A. Galperin, Tyll Krüger, Serge Troubetzkoy

A polygon is called rational if the angle between each pair of sides is a rational multiple of $π.$ The main theorem we will prove is Theorem 1: For rational polygons, periodic points of the billiard flow are dense in the phase space of the billiard flow. This is a strengthening of Masur's theorem, who has shown that any rational polygon has ``many'&

Hideaki Aoyama, Shinya Wada

The valley structure associated with quantum meta-stability is examined. It is defined by the new valley equation, which enables consistent evaluation of the imaginary-time path-integral. We study the structure of this new valley equation and solve these equations numerically. The valley is shown to contain the bounce solution, as well as other bubble struct

Yutaka Hosotani

In a class of renormalizable three-dimensional abelian gauge theory the Lorentz invariance is spontaneously broken by dynamical generation of a magnetic field $B$. The true ground state resembles that of the quantum Hall effect. An originally topologically massive photon becomes gapless, fulfilling the role of the Nambu-Goldstone boson associated with the sp

A. Khvedelidze, V. Pervushin

The physical variables for pure Yang - Mills theory in four - dimensional Minkowskian space time are constructed without using a gauge fixing condition} by the explicit resolving of the non - Abelian Gauss constraint and by the Bogoliubov transformation that diagonalizes the kinetic term in reduced action (action on constraint shell). As a result, the reduce

Kazuo Ghoroku

We have examined effective theory induced by gauged WZW models, in which the tachyon field is added as a marginal operator. Due to this operator added, we must further add the higher order corrections, which modifies the original configuration, to make the theory full-conformally invariant. It has been found that 2d is a critical dimension in the sense that

Kimio Ueno, Michitomo Nishizawa

A $q$-analogue of the Hurwitz zeta-function is introduced through considerations on the spectral zeta-function of quantum group $SU_{q}(2)$, and its analytic aspects are studied via the Euler-MacLaurin summation formula. Asymptotic formulas of some relevant $q$-functions are discussed.

A. Petermann, A. Zichichi

We present an explicit solution of superstring effective equations, represented by gravitational waves and dilaton backgrounds. Particular solutions will be examined in a forthcoming note.

A. L. Carey, M. K. Murray

Anomalies can be viewed as arising from the cohomology of the Lie algebra of the group of gauge transformations and also from the topological cohomology of the group of connections modulo gauge transformations. We show how these two approaches are unified by the transgression map. We discuss the geometry behind the current commutator anomaly and the Faddeev-

M. Beneke

The relation between the pole quark mass and the $\overline{MS}$-renormalized mass is governed by an infrared renormalon singularity, which leads to an ambiguity of order $Λ_{QCD}$ in the definition of the pole mass. We use the renormalization group and heavy quark effective theory to determine the exact nature of this singularity up to an overall normalizat

B. Kerbikov, D. Kharzeev

We discuss the $p\bar{p}$ annihilation into a pair of charmed $D$ mesons not far from the threshold of the reaction. An interesting interference pattern in the differential cross section is predicted to arise from the existence of both $t$-channel charmed-baryon exchange and $s$-channel $Ψ^{''}$ charmonium resonance amplitudes. We argue that the expe

Johannes Blümlein

The gluon contributions to $F_L(x,Q^2)$ in ${\cal O}(α_s)$ are calculated taking into account the transverse momentum of the initial state parton. In comparison with collinear factorization $F_L(x,Q^2)$, is not affected at large $x$ but takes smaller values in the small $x$ range. The onset of the $k_{\perp}$ effect is a function of $Q^2$.

S. Narison

Using the recent {\it world average} $α_s(M^2_Z)= 0.118 \pm 0.006$, we give the {\it first direct extraction} from the $Ψ$ and $Υ$ data of the values of the {\it running heavy quark masses} within QCD spectral sum rules to two-loops in the $\overline {MS}$-scheme: $\mr_b(M^{PT2}_b)$ = $(4.23~^{+0.03}_{-0.04} \pm 0.02)$ GeV and $\mr_c(M^{PT2}_c)$ = $(1.23~^{+

J. T. Liu, D. Ng

Motivated by the $\sim 2σ$ discrepancy between the experimental value for $R_b$ and the theoretical prediction of the Standard Model, we examine the effect of new physics on the $Z$-$b$-$\overline{b}$ vertex. Using general results for both new scalars and gauge bosons, we show that two conditions must be satisfied in order for new physics to give observable

H. Gausterer, C. B. Lang

We study the partition function of the model formulated with Wilson fermions with only one species, both analytically and numerically. At strong coupling we construct the solution for lattice size up to $8\times 8$, a polynomial in the hopping parameter up to $O(\ka^{128})$. At $\be>0$ we evaluate the expectation value of the fermion determinant for complex

Gilbert Weinstein

Let $\M$ be a classical Riemannian globally symmetric space of rank one and non-compact type. We prove the existence and uniqueness of solutions to the Dirichlet problem for harmonic maps into $\M$ with prescribed singularities along a closed submanifold of the domain. This generalizes our previous work where such maps into the hyperbolic plane were construc

Thierry Martin

The recent progress on 1 D interacting electrons systems and their applications to study the transport properties of quasi one dimensional wires is reviewed. We focus on strongly correlated electrons coupled to low energy acoustic phonons in one dimension. The Wentzel--Bardeen singularity suppresses antiferromagnetic fluctuations and pushes the system toward

Thierry Martin, Daniel Loss

The Green function and the ordering correlation functions of a system of electrons coupled to acoustic phonons are calculated explicitly. The sensitivity of the correlation function exponents to the Wentzel-Bardeen singularity is discussed. A phase diagram is established for the Hubbard model coupled to phonons, using the integral equations of Lieb and Wu. B

Daniel Loss, Thierry Martin

Using a Luttinger liquid description, the correlation function exponents of various response functions are calculated. Their striking sensitivity to the non perturbative Wentzel-Bardeen singularity is discussed. For the Hubbard model coupled to phonons, the equivalent of a phase diagram is established. By increasing the filling factor towards half filling, t

F. Zertuche, R. López-Peña, H. Waelbroeck

Using an asymmetric associative network with synchronous updating, it is possible to recall a sequence of patterns. To obtain a stable sequence generation with a large storage capacity, we introduce a threshold that eliminates the contribution of weakly correlated patterns. For this system we find a set of evolution equations for the overlaps of the states w

Kurt Wiesenfeld, James W. Swift

We derive the averaged equations describing a series array of Josephson junctions shunted by a parallel inductor-resistor-capacitor load. We assume that the junctions have negligable capacitance ($β= 0$), and derive averaged equations which turn out to be completely tractable: in particular the stability of both in-phase and splay states depends on a single

Karl Gebhardt, Philippe Fischer

We use radial velocities of member stars and cluster surface brightness profiles to non-parametrically determine the mass density profiles and isotropic phase-space distribution functions $f(E)$ for the globular clusters M15 (NGC7078), 47~Tuc (NGC104), NGC~362, and NGC~3201. Assuming isotropy and using the velocity dispersion and surface brightness profiles,

C. Lissandrini, S. Cristiani, F. La Franca

The sky subtraction performances of multi-fiber spectrographs are discussed, analysing in detail the case of the OPTOPUS system at the 3.6 meter ESO telescope at La Silla. A standard technique, based on flat-fields obtained with a uniformly illuminated screen on the dome, provides poor results. A new method has been developed, using the [OI] emission line at

Joachim Wambsganss, Bohdan Paczynski

The geometry of the quadruple lens system Q2237+0305 is modeled with a simple astigmatic lens: a power-law mass distribution: m \propto r^βwith an external shear γ. The image positions can be reproduced with an accuracy better than 0.01 arcsec for any 0.0 < β< 1.85 and the corresponding value of γ= 0.1385 - 0.0689 β. This is a factor of about 4 more precise

Zhan-Ning Hu

In this paper the three-dimensional vertex model is given, which is the duality of the three-dimensional Baxter-Bazhanov (BB) model. The braid group corresponding to Frenkel-Moore equation is constructed and the transformations $R, I$ are found. These maps act on the group and denote the rotations of the braids through the angles $π$ about some special axes.

D. J. Dean, S. E. Koonin, K. Langanke, P. B. Radha

We have studied the properties of A=54 and A=64 isobars at temperatures T \leq 2 MeV via Monte Carlo shell model calculations with two different residual interactions. In accord with empirical indications, we find that the symmetry energy coefficient, b_{sym}, is independent of temperature to within 0.6 MeV for T \leq 1 MeV. This is in contrast to a recent s

P. Bamert, C. P. Burgess, R. N. Mohapatra

We investigate the possibility of producing neutrinoless double beta decay without having an electron neutrino with a mass in the vicinity of 1 eV. We do so by having a much lighter electron neutrino mix with a much heavier (m > 1 GeV) sterile neutrino. We study the constraints on the masses and mixings of such heavy sterile neutrinos from existing laborator

S. Kirsch, T. Riemann

SMATASY is an interface for the ZFITTER package and may be used for the model independent description of the Z resonance at LEP 1 and SLC. It allows the determination of the Z mass and width and its resonance shape parameters r and j for cross-sections and their asymmetries. The r describes the peak height and j the interference of the Z resonance with photo

Detlef Lohse

We show that the $P_u(\om) \propto \om^{-7/3}$ shear velocity power spectrum gives rise to a $P_Θ(\om ) \propto \om^{-4/3}$ power spectrum for a passively advected scalar, as measured in experiment [K. Sreenivasan, Proc. R. Soc. London A {\bf 434}, 165 (1991)]. Applying our argument to high Rayleigh number Rayleigh Benard flow, we can account for the measure

W. M. Kloet, B. Loiseau

A simple $ππ$, $\bar{K}K$, and $ρρ$($ωω$) fully coupled channel model is proposed to predict the isoscalar S-wave phase shifts and inelasticities for $ππ$ scattering in the 1.0 to 2.0 GeV region. The S-matrix is required to exhibit poles corresponding to the established isoscalar J$^π$ = 0$^+$ resonances f$_0$(975), f$_0$(1400), and f$_0$(1710). A dominant f

Søren Köster

This text, written as dissertation within the M.Sc. course in particle theory at the Centre for Particle Theory, University of Durham, during the academic year 1993/94, reviews two articles by D.Gross and by D.Gross and W.Taylor which interpret the 1/N- expansion of the partition function of $QCD_2$ as string perturbation series. For this required mathematic

Zhan-Ning Hu, Bo-Yu Hou

In this letter we show that the restricted star-triangle relation introduced by Bazhanov and Baxter can be obtained either from the star-triangle relation of chiral Potts model or from the star-square relation which is proposed by Kashaev $et ~al$ and give a response of the guess which is suggested by Bazhanov and Baxter in Ref. \cite{b2}.

K. Behrndt

We investigate quantum corrections for a cosmological solution of the string effective action. Starting point is a classical solution containing an antisymmetric tensor field, a dilaton and a modulus field which has singularities in the scalar fields. As a first step we quantize the scalar fields near the singularity with the result that the singularities di

Ole Warnaar, Paul A. Pearce

The dilute A$_3$ lattice model in regime 2 is in the universality class of the Ising model in a magnetic field. Here we establish directly the existence of an E$_8$ structure in the dilute A$_3$ model in this regime by expressing the 1-dimensional configuration sums in terms of fermionic sums which explicitly involve the E$_8$ root system. In the thermodynam

Atsuo Kuniba, Junji Suzuki

Functional relations are proposed for transfer matrices of solvable vertex models associated with the twisted quantum affine algebras $U_q(X^{(κ)}_n)$ where $X^{(κ)}_n = A^{(2)}_n, D^{(2)}_n, E^{(2)}_6$ and $D^{(3)}_4$. Their solutions are obtained for $A^{(2)}_n$ and conjectured for $D^{(3)}_4$ in the dressed vacuum form in the analytic Bethe ansatz.

Craig D. Roberts

The nonperturbative, Dyson-Schwinger equation approach to solving QCD provides a straightforward, microscopic description of dynamical chiral symmetry breaking and confinement. It is an ideal tool for the study of pion observables. This is illustrated via its application to the calculation of: the $\pi$-$\pi$ scattering lengths $a_0^0$, $a_0^2$, $a_1^1$, $a_

D. Atwood, B. Blok, A. Soni

We use existing measurements of $D^-\to K^{\ast0}ρ^-$ and $B\to ψ+K^\ast$, coupled with flavor independence of QCD, and with vector meson dominance to show that long distance contributions to $B\to ρ+γ$ are potentially very serious. We note that long distance (LD) contributions can be appreciably different in $B^-\to ρ^-+γ$ and $B^0\to ρ^0 (ω) +γ$. All radia

W. -K. Tang

We show that the new QCD production mechanisms which were proposed by S. J. Brodsky, P. Hoyer, A. H. Mueller and the author can explain at least some of the anomalous behavior of open and/or closed charm production at large $x_{F}$.

W. -K. Tang, S. J. Brodsky, M. Vänttinen, P. Hoyer

Measurements of the polarization of $\jp$ produced in pion-nucleus collisions are in disagreement with leading twist QCD prediction where $\jp$ is observed to have negligible polarization whereas theory predicts substantial polarization. We argue that this discrepancy cannot be due to poorly known structure functions nor the relative production rates of $\jp

Eugene Golowich, Sandip Pakvasa

We reconsider the `long-range&#39; component of the radiative transition $B \to K^* γ$. A careful analysis of the vector dominance amplitude $B \to V_1 V_2 \to V_1 γ$ is carried out, with emphasis on the role of gauge invariance. The procedure for incorporating phenomenological $B\to V_1 V_2$ data is identified and polarization data, only recently available,

K. Jedamzik, G. M. Fuller

We investigate the transport of baryon number across phase boundaries in a putative first order QCD-phase transition. Two independent phenomenological models are employed to estimate the baryon penetrability at the phase boundary: chromoelectric flux tube models; and an analogy to baryon-baryon coalescence in nuclear physics. Our analysis indicates that bary

A. A. Bel&#39;kov, A. V. Lanyov, A. Schaale, S. Scherer

In this work we present a strong chiral meson Lagrangian up to and including $O(p^6)$ in the momentum expansion. It is derived from the Nambu--Jona-Lasinio (NJL) model using the heat-kernel method. Identities related to the properties of covariant derivatives of the chiral matrix $U$ as well as field transformations have been used to obtain a minimal set of

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

{}From the literature one infers that the bulk of the order $α_{s}$ corrections to the Drell-Yan cross sections $dσ/dm$ and $m^{3}d^{2}σ/dmdx_{F}$ is constituted by the soft plus virtual gluon part of the coefficient function. In the case of $dσ/dm$ it can be shown that at fixed target energies the effect of the exact order $α_{s}^{2}$ corrected coefficient

Chi-Keung Chow

New universality appears for the baryon Isgur--Wise form factor in the large $N_c$ limit. It is found that the semileptonic $Λ_b \rightarrow Λ_c$ and $Σ_b^{(*)} \rightarrow Σ^{(*)}_c$ decays are described by the same form factor, which can be calculated analytically. In the exact chiral $SU(3)$ limit, the same form factor is applicable to semileptonic $Ω_b^{

Martin Hasenbusch

I present a new improved estimator for the correlation function of 2D nonlinear sigma models. Numerical tests for the 2D XY model and the 2D O(3)-invariant vector model were performed. For small physical volume, i.e. a lattice size small compared to the to the bulk correlation length, a reduction of the statistical error of the finite system correlation leng

J. S. F. Chan, R. B. Mann

The actions of the ``$R=T$&#39;&#39; and string-inspired theories of gravity in (1+1) dimensions are generalized into one single action which is characterized by two functions. We discuss differing interpretations of the matter stress-energy tensor, and show how two such different interpretations can yield two different sets of field equations from this acti

E. I. Guendelman, A. B. Kaganovich

In many interesting models, including superstring theories, a negative vacuum energy is predicted. Although this effect is usually regarded as undesirable from a cosmological point of view, we show that this can be the basis for a new approach to the cosmology of the early Universe. In the framework of quantum cosmology (in higher dimensions) when we conside

Marek Biesiada, Svend E. Rugh

It is tempting to raise the issue of (metric) chaos in general relativity since the Einstein equations are a set of highly nonlinear equations which may exhibit dynamically very complicated solutions for the space-time metric. However, in general relativity it is not easy to construct indicators of chaos which are gauge-invariant. Therefore it is reasonable

M. Buttiker

The currents at the terminals of a mesoscopic conductor are evaluated in the presence of slowly oscillating potentials applied to the contacts of the sample. The need to find a charge and current conserving solution to this dynamic current partition problem is emphasized. We present results for the electro-chemical admittance describing the long range Coulom

F. Y. Wu, P. Pant, C. King

A new link invariant is derived using the exactly solvable chiral Potts model and a generalized Gaussian summation identity. Starting from a general formulation of link invariants using edge-interaction spin models, we establish the uniqueness of the invariant for self-dual models. We next apply the formulation to the self-dual chiral Potts model, and obtain

M. T. Batchelor, J. Suzuki, C. M. Yung

We derive the nested Bethe Ansatz solution of the fully packed O($n$) loop model on the honeycomb lattice. From this solution we derive the bulk free energy per site along with the central charge and geometric scaling dimensions describing the critical behaviour. In the $n=0$ limit we obtain the exact compact exponents $γ=1$ and $ν=1/2$ for Hamiltonian walks

H. Dahle, S. J. Maddox, Per B. Lilje

We present new results from extremely deep, high-resolution images of the field around the double quasar QSO 0957+561. A possible gravitational arc system near the double quasar has recently been reported, which, if real, would set strong constraints on determinations of the Hubble constant from the time delay in the double quasar. We find that both the morp

D. A. Lowe, L. Thorlacius

Above the Hagedorn energy density closed fundamental strings form a long string phase. The dynamics of weakly interacting long strings is described by a simple Boltzmann equation which can be solved explicitly for equilibrium distributions. The average total number of long strings grows logarithmically with total energy in the microcanonical ensemble. This i

J. E. Rankin

This discussion examines recent developments in the theory of a Weyl-like, Cartan geometry with natural Schrödinger field behavior proposed previously. In that model, very nearly exactly a coupled Einstein-Maxwell- Schrödinger, classical field theory emerges from a gauge invariant, purely geometric action based solely on variations of the electromagnetic pot

J. Czyzewski

Azimuthal asymmetry of vector-meson production in single-transversely polarized proton-proton collisions ($p\up p$) is calculated in the string model of particle production. The asymmetry is generated only during fragmentation of a high-energy quark into hadrons. The obtained asymmetry of the $ρ^\pm$ is opposite in sign to that of $π^\pm$ mesons. On the othe

L. Turban, P. E. Berche, B. Berche

We investigate the influence of aperiodic perturbations on the critical behaviour at a second order phase transition. The bond and site problems are compared for layered systems and aperiodic sequences generated through substitution. In the bond problem, the interactions between the layers are distributed according to an aperiodic sequence whereas in the sit

C. Kaiser, L. Turban

The fractal structure of directed percolation clusters, grown at the percolation threshold inside parabolic-like systems, is studied in two dimensions via Monte Carlo simulations. With a free surface at y=\pm Cx^k and a dynamical exponent z, the surface shape is a relevant perturbation when k<1/z and the fractal dimensions of the anisotropic clusters vary co

Yan V. Fyodorov, Alexander D. Mirlin

We calculate the distribution of eigenfunction amplitudes and the variance of the ``inverse participation ratio&#39;&#39; (IPR) in disordered metallic samples. A relation is established between the distribution function of IPR and that of ``level velocities&#39;&#39; -- parametric derivatives of energy levels with respect to a random perturbation.

M. Yu. Lashkevich

The Kyoto group (Jimbo, Miwa, Nakayashikiet al.) showed that the partition function and correlation funtions of the eight-vertex model in antiferromagnetic phases can be calculated using simple analytical properties of the $R$-matrix. We extend these methods to ferromagnetic and disordered phases. We use Baxter&#39;s symmetries to obtain appropriate parametr

S. Kuyucak, A. E. Stuchbery

It is shown that a consistent description of magnetic dipole properties in transitional nuclei can be obtained in the interacting boson model-2 by F-spin breaking mechanism, which is associated with differences between the proton and neutron deformations. In particular, the long standing anomalies observed in the $g$-factors of the Os-Pt isotopes are resolve

B. Malcolm Brown, William Desmond Evans, Mourad E. H. Ismail

We find the adjoint of the Askey-Wilson divided difference operator with respect to the inner procuct on L^2(-1,1,(1-x^2)^-1/2 dx) defined as a Cauchy principle value and show that the Askey-Wilson polynomials are solutions of a q-Sturm-Liouville problem. From these facts we deduce various properties of the polynomials in a simple and straightforward way. We

Denny H. Leung

Let $\msp$ be a measure space and let $1 < p < \infty$. The {\em weak $L^p$}\/ space $\wlp$ consists of all measurable functions $f$ such that \[ \|f\| = \sup_{t>0}t^{\frac{1}{p}}f^*(t) < \infty,\] where $f^*$ is the decreasing rearrangement of $|f|$. It is a Banach space under a norm which is equivalent to the expression above. In this paper, we pursue the

Peter G. Casazza, Nigel J. Kalton

Let $X$ be a Banach space with an unconditional finite-dimensional Schauder decomposition $(E_n)$. We consider the general problem of characterizing conditions under which one can construct an unconditional basis for $X$ by forming an unconditional basis for each $E_n.$ For example, we show that if $\sup \dim E_n<\infty$ and $X$ has Gordon-Lewis local uncond

Nigel J. Kalton

We show that if $X$ is a quasi-Banach space with trivial dual then every continuous function $f:[0,1]\to X$ has a primitive, answering a question of M.M. Popov.

Eric Zaslow

We present evidence for an undiscovered link between N=2 supersymmetric quantum field theories and the mathematical theory of helices of coherent sheaves. We give a thorough review for nonspecialists of both the mathematics and physics involved, and invite the reader to take up the search for this elusive connection.

S. Bornholdt, N. Tetradis, C. Wetterich

We explore the Coleman-Weinberg phase transition in regions outside the validity of perturbation theory. For this purpose we study a Euclidean field theory with two scalars and discrete symmetry in four dimensions. The phase diagram is established by a numerical solution of a suitable truncation of exact non-perturbative flow equations. We find regions in pa

Wen-Jui Huang

We study the generalization of second Gelfand-Dickey bracket to the superdifferential operators with matrix-valued coefficients. The associated Miura transformation is derived. Using this bracket we work out a nonlocal and nonlinear N=2 superalgebra which contains the N=2 super Virasoro algebra as a subalgebra. The bosonic limit of this algebra is considered

D. de Florian, L. N. Epele, H. Fanchiotti, C. A. Garcia Canal

We analyze spin dependent parton distributions consistent with the most recent measurements of the spin dependent deep inelastic scattering structure functions and obtained in the framework of the spin dilution model. Predictions for the doubly polarised proton-proton Drell-Yan asymmetry, for the high $p_{T}$ photon production mechanism and $J/Ψ$ excitation

Charles B. Chiu, Duane A. Dicus

We consider the dip-peak structures in the J=0 partial wave amplitudes for processes $γγ\rightarrow W^+W^-~ \mbox{and}~γγ,gg\rightarrow t\overline{t}$ taking into account the corresponding Born term process and the rescattering process where the intermediate state is rescattered through the exchange of Higgs resonance state in the direct channel.

C. L. Schat, N. N. Scoccola, C. Gobbi

The strong and electromagnetic properties of the Lambda(1405) hyperon are studied in the framework of the bound state soliton model. We explicitly evaluate the strong coupling constant g(Lambda^*-N-K), the Lambda^* magnetic moment, mean square radii and radiative decay amplitudes. The results are shown to be in general agreement with available empirical data

Jonathan L. Feng, Matthew J. Strassler

If accessible at LEP II, chargino production is likely to be one of the few available supersymmetric signals for many years. We consider the prospects for the determination of fundamental supersymmetry parameters in such a scenario. The study is complicated by the dependence of observables on a large number of these parameters. We propose a straightforward p

J. Maalampi, M. Roos

We fit the ${\cal CKM}$-matrix to all recent data with the following free parameters: three mixing angles, the CP-violating angle $δ$ in the Maiani parametrisation, the top quark mass $m_t$, and the product $f_B{\cal B}_{\B}^{1/2}$, where $f_B$ is the $B$-meson decay parameter and ${\cal B}_{\B}$ is the bag parameter. Our fits span a contiguous region in the

I. G. Avramidi

An overview about recent progress in the calculation of the heat kernel and the one-loop effective action in quantum gravity and gauge theories is given. We analyse the general structure of the standard Schwinger-De Witt asymptotic expansion and discuss the applicability of that to the case of strongly curved manifolds and strong background fields. We argue

T. P. Devereaux, A. Virosztek, A. Zawadowski

The Raman spectrum of the $B_{1g}$ phonon in the superconducting cuprate materials is investigated theoretically in detail in both the normal and superconducting phases, and is contrasted with that of the $A_{1g}$ phonon. A mechanism involving the charge transfer fluctuation between the two oxygen ions in the CuO$_2$ plane coupled to the crystal field perpen

J. P. Hessling, Yu. Galperin, M. Jonson, R. I. Shekhter

We propose a theoretical model for the low-frequency noise observed in a quantum point contact (QPC) electrostatically defined in the 2D electron gas at a GaAs-AlGaAs interface. In such contacts electron scattering by soft impurity- or boundary potentials coherently splits an incoming wave function between different transverse modes. Interference between the

Gongwen Peng, Hans J. Herrmann

We simulate the granular flow in a narrow pipe with a lattice-gas automaton model. We find that the density in the system is characterized by two features. One is that spontaneous density waves propagate through the system with well-defined shapes and velocities. The other is that density waves are so distributed to make the power spectra of density fluctuat

Silvio Franz, John Hertz

We study the off-equilibrium relaxational dynamics of the Amit-Roginsky $ϕ^3$ field theory, for which the mode coupling approximation is exact. We show that complex phenomena such as aging and ergodicity breaking are present at low temperature, similarly to what is found in long range spin glasses. This is a generalization of mode coupling theory of the stru

S. C. Erwin, G. V. Krishna, E. J. Mele

The low-temperature structure of A1C60 (A=K, Rb) is an ordered array of polymerized C60 chains, with magnetic properties that suggest a non-metallic ground state. We study the paramagnetic state of this phase using first-principles electronic-structure methods, and examine the magnetic fluctuations around this state using a model Hamiltonian. The electronic

Zlatko Tesanovic, Igor F. Herbut

The &#34;glassy&#34; superconducting transition at high magnetic fields can be induced by columnar disorder. A model is proposed in which the thermodynamics of Bose condensation of Cooper pairs into the lowest Landau-level eigenstate of the random potential can be solved exactly. The solution reflects a peculiar character of the high-field limit: for example