May 1998 arXiv papers

Yuri Ozhigov

We show that Durr-Hoyer's quantum algorithm of searching for extreme point of integer function can not be sped up for functions chosen randomly. Any other algorithm acting in substantially shorter time $o(\sqrt{2^n})$ gives incorrect answer for the functions with the single point of maximum chosen randomly with probability converging to 1. The lower boun

Georg M. Gandenberger

We construct new non-diagonal solutions to the boundary Yang-Baxter-Equation corresponding to a two-dimensional field theory with U_q(a_2^(1)) quantum affine symmetry on a half-line. The requirements of boundary unitarity and boundary crossing symmetry are then used to find overall scalar factors which lead to consistent reflection matrices. Using the bounda

D. B. Lichtenberg

In some models, exotic baryons with strangeness and anticharm or antibeauty should exist and even be stable against strong decay. We consider the stability of such possible exotic baryons, which in the constituent quark picture are called pentaquarks (each is composed of four quarks and an antiquark). Our model is based on diquark clustering and supersymmetr

E. E. Zabrodin, L. V. Bravina, L. P. Csernai, H. Stöcker

We reexamine the scenario of homogeneous nucleation of the quark-gluon plasma produced in ultra-relativistic heavy ion collisions. A generalization of the standard nucleation theory to rapidly expanding system is proposed. The nucleation rate is derived via the new scaling parameter $λ_Z$. It is shown that the size distribution of hadronic clusters plays an

Matthias Neubert

The observation of a sizable direct CP asymmetry in the inclusive decays B -> X_s gamma would be a clean signal of New Physics. In the Standard Model, this asymmetry is below 1% in magnitude. In extensions of the Standard Model with new CP-violating couplings, large asymmetries are possible without conflicting with the experimental value of the B -> X_s gamm

Yukinori Nagatani

We find that the Hawking radiation of black holes can create the baryon number in the Higgs phase vacuum of the extended standard model with 2-Higgs doublets. We propose new scenarios of baryogenesis based on the black holes, and one of our scenarios can explain the origin of baryon number in our universe, if most of the matter existed as primordial black ho

Laurent Querella

We develop a Hamiltonian formulation of Bianchi type-I cosmological model in conformal gravity, i.e. the theory described by a Lagrangian which involves the quadratic curvature invariant constructed from the Weyl tensor, in four dimensions. We derive the explicit forms of the super-Hamiltonian and the constraint expressing the conformal invariance of the the

Helio V. Fagundes

A few corrections and comments are made upon a previously published paper by the author (Gen. Rel. Gravit. 24, 199 (1992)), on the subject of cosmological models with compact spatial sections.

Larissa V. Bravina, Eugene E. Zabrodin

The nucleation rates derived for the condensation from a supersaturated vapor are examined both in the classical theory and in the modern coarse-grained field theory. By virtue of the scaling variable $λ_Z$ it is shown that the method of steepest descent is irrelevant to evaluate the nucleation rate in the proximity of the critical point in the capillary app

Hae-Young Kee, C. M. Varma

We present analytic results for the polarizabilities, $χ({\bf Q},ω)$, in the charge, spin, and current channels for two-dimensional s- and d-wave superconductors for large momentum transfer. A collective mode in the charge channel is predicted to exist for extremum vectors of the Fermi-surface with energy below twice the maximum superconducting gap. Such mod

Larissa V. Bravina, Eugene E. Zabrodin

The classical nucleation theory of Becker, Döring and Zeldovich is compared with the Langer coarse-grained field approach to the nucleation phenomenon. Both formalisms have been applied to the condensation from a supersaturated vapor. It is shown that the nucleation rate derived in the classical theory can be expressed in a form equivalent to that of the fie

V. M. Apalkov, Yu. I. Boiko, V. V. Slezov, H. D. Carstanjen

We consider in the article the influence of the irradiation and the internal sinks of the point defects on the rate of the flattening of the surface structure in solids. The irradiation produces only the additional external sources of point defects(vacancies and interstitial atoms). The general system of equations is formulated. The solution of the system on

Dragomir R. Radev

This paper presents the results of a study on the semantic constraints imposed on lexical choice by certain contextual indicators. We show how such indicators are computed and how correlations between them and the choice of a noun phrase description of a named entity can be automatically established using supervised learning. Based on this correlation, we ha

Robert J. Nemiroff

The density of stars and MACHOs in the universe could theoretically be determined or limited by simultaneous measurements of compact sources by well separated observers. A gravitational lens effect would be expected to create a slight differential amplification between the observers detectable with sufficiently sensitive relative photometry: "lensing par

G. Nelemans, T. M. Tauris

We propose a scenario to form low-mass, single, slow rotating white dwarfs from a solar-like star accompanied by a massive planet, or a brown dwarf, in a relatively close orbit (e.g. HD 89707). Such white dwarfs were recently found by Maxted & Marsh (1998). When the solar-like star ascends the giant branch it captures the planet and the subsequent spiral-in

Ming Deng, Bradley E. Schaefer

We present strong evidence of time stretching in the peak-to-peak time scales in the light curves of BATSE Gamma Ray Bursts (GRBs). Extensive tests are performed on artificially dilated bursts to verify that the procedure for extracting the peak-to-peak time scales correctly recovers the stretching of bursts. The resulting robust algorithm is then applied to

M. S. Oey, S. A. Smedley

Was star formation in the OB associations, LH 51 and LH 54, triggered by the growth of the superbubble DEM 192? To examine this possibility, we investigate the stellar contents and star formation history, and model the evolution of the shell. H-R diagrams constructed from UBV photometry and spectral classifications indicate highly coeval star formation, with

Toshio Tsuchiya, Vladimir Korchagin, Keiichi Wada

Using N-body and SPH modeling we perform 3D numerical simulations of head-on collisions between gas rich disk galaxies, including collisions between counter-rotating disks and off-center collisions. Pure stellar intruders do not produce gaseous plumes similar to those seen in the Cartwheel and VII Zw466 complexes of interacting galaxies; the presence of gas

U. Kolb, A. R. King, H. Ritter

We consider a recently-proposed alternative explanation of the CV period gap in terms of a revised mass-radius relation for the lower main sequence. We show that no such thermal-equilibrium relation is likely to produce a true gap. Using population synthesis techniques we calculate a model population that obeys the claimed equilibrium mass-radius relation. A

C. -W. H. Lee, S. G. Rajeev

We consider quantum dynamical systems whose degrees of freedom are described by $N \times N$ matrices, in the planar limit $N \to \infty$. Examples are gauge theoires and the M(atrix)-theory of strings. States invariant under U(N) are `closed strings', modelled by traces of products of matrices. We have discovered that the U(N)-invariant opertors acting

Juergen Baacke, Katrin Heitmann, Carsten Patzold

We consider the time evolution of systems in which a spatially homogeneous scalar field is coupled to fermions. The quantum back-reaction is taken into account in one-loop approximation. We set up the basic equations and their renormalization in a form suitable for numerical computations. The initial singularities appearing in the renormalized equations are

C. G. Tinney, I. N. Reid

We present the results of high-resolution (1-0.4A) optical spectroscopy of a sample of very low-mass stars. These data are used to examine the kinematics of the stars at the bottom of the hydrogen-burning main sequence. No evidence is found for a significant difference between the kinematics of the stars in our sample with I-K > 3.5 (MBol > 12.8) and those o

N. S. Mosyagin, M. G. Kozlov, A. V. Titov

Ab initio calculation of the hyperfine, P-odd, and P,T-odd constants for the YbF molecule was performed with the help of the recently developed technique, which allows to take into account correlations and polarization in the outercore region. The ground state electronic wave function of the YbF molecule is found with the help of the Relativistic Effective C

Y. Umino, M. K. Banerjee

In this two part series a chiral confining model of baryons is used to describe low--lying negative parity resonances $N^*$, $Δ^*$, $Λ^*$ and $Σ^*$ in the mean field approximation. A physical baryon in this model consists of interacting valence quarks, mesons and a color and chiral singlet hybrid field coexisting inside a dynamically generated confining regi

B. K. Fujikawa, S. J. Asztalos, R. M. Clark, M. -A. Deleplanque-Stephens

We report on a new measurement of the strength of the superallowed 0+->0+ transition in the beta-decay of 10C: 10C(0+,g.s.)->10B(0+,1.74MeV)+e+nu. The experiment was done at the LBNL 88-inch cyclotron using forty seven GAMMASPHERE germanium detectors. Precise knowledge of this branching ratio is necessary to compute the superallowed Fermi ft, which gives the

Maks A. Akivis, Vladislav V. Goldberg

For a hypersurface V of a conformal space, we introduce a conformal differential invariant I = h^2/g, where g and h are the first and the second fundamental forms of V connected by the apolarity condition. This invariant is called the conformal quadratic element of V. The solution of the problem of conformal rigidity is presented in the framework of conforma

Kazumi Okuyama, Yuji Sugawara

We study the (p,q)5-brane dynamics from the viewpoint of Matrix string theory in the T-dualized ALE background. The most remarkable feature in the (p,q)5-brane is the existence of ``fractional string'', which appears as the instanton of 5-brane gauge theory. We approach to the physical aspects of fractional string by means of the two types of Matrix string p

V. A. Miransky

The phenomenon of the magnetic catalysis of dynamical symmetry breaking is based on the dimensional reduction $D\to D-2$ in the dynamics of fermion pairing in a magnetic field. We discuss similarities between this phenomenon and the Aharonov-Bohm effect. This leads to the interpretation of the dynamics of the (1+1)-dimensional Gross-Neveu model with a non-in

T. Hambye

We analyze long-distance contributions to the K --> pi pi amplitudes relevant for the Delta I = 1/2 selection rule in the framework of the 1/N_c expansion. We use a modified prescription for the identification of meson momenta in the chiral loop corrections to gain a consistent matching with the short-distance part. Our approach involves a separation of non-

T. Hambye, P. Soldan

In this talk we discuss the general method to calculate loop corrections to Delta S=1 density-density operators in the 1/N_c approach. As a result we present the long-distance evolution of the operators Q_6 and Q_8 to O(p^0/N_c) in the chiral and the 1/N_c expansions.

Ram Brustein, Merav Hadad

Axions are produced during a period of dilaton-driven inflation by amplification of quantum fluctuations. We show that for some range of string cosmology parameters and some range of axion masses, primordial axions may constitute a large fraction of the present energy density in the universe in the form of cold dark matter. Due to the periodic nature of the

U. Cotti, R. Gaitan, A. Hernandez, W. Ponce

Lepton family number violation processes arise in the $SU(6)_L \otimes U(1)_Y$ model due to the presence of an extra neutral gauge boson, Z$'$, with family changing couplings, and due to the fact that this model demands the existence of heavy exotic leptons. The mixing of the standard Z with Z$'$ and the mixing of ordinary leptons with exotic ones in

Richard J. Epp, R. B. Mann

If one encodes the gravitational degrees of freedom in an orthonormal frame field there is a very natural first order action one can write down (which in four dimensions is known as the Goldberg action). In this essay we will show that this action contains a boundary action for certain microscopic degrees of freedom living at the horizon of a black hole, and

M. A. H. MacCallum

Integrability in general tetrad formalisms is reviewed, following and clarifying work of Papapetrou and Edgar. The integrability conditions are (combinations of) the Bianchi equations and their consequences. The introduction of additional constraints is considered. Recent results on the conservation of constraints in the 1+3 covariant formulation of cosmolog

Peter Breitenlohner, Dieter Maison

In a previous paper with Gibbons [CMP 120 (1987) 295] we derived a list of three dimensional symmetric space $σ$-model obtained by dimensional reduction of a class of four dimensional gravity theories with abelian gauge fields and scalars. Here we give a detailed analysis of their group theoretical structure leading to an abstract parametrization in terms of

S. Yu. Alexandrov, D. V. Vassilevich

To write down a path integral for the Ashtekar gravity one must solve three fundamental problems. First, one must understand rules of complex contour functional integration with holomorphic action. Second, one should find which gauges are compatible with reality conditions. Third, one should evaluate the Faddeev-Popov determinant produced by these conditions

A. Rakitin, M. Ya. Valakh, N. I. Klyui, V. G. Visotski

A microscopic model, which describes specific features of the electronic spectrum of various allotropic forms of amorphous carbon as being responsible for their structure peculiarities, is presented. It is shown that the formation of a double-well potential is a possible driving force for this behavior.

Jose M. Sancho, Aldo H. Romero, Katja Lindenberg

The Kramers problem in the energy-diffusion limited regime of very low friction is difficult to deal with analytically becasue of the repeated recrossings of the barrier that typically occur before an asymptotic rate constant is achieved. Thus, the transmission coefficient of particles over the potential barrier undergoes oscillatory behavior in time before

Roger Coziol, Reinaldo R. de Carvalho, Hugo V. Capelato, Andre L. B. Ribeiro

We present the analysis of the spectra of 62 galaxies in 15 compact groups. The galaxies were classified in four activity classes: galaxies without emission, starburst nucleus galaxies (SBNGs), luminous AGNs and low-luminosity AGNs (LLAGNs). The star formation in the HCG starbursts is more intense than in normal spirals, but comparable to those in the field

P. Magdziarz

We discuss the observational phenomenology of Seyferts from the point of view of the disk model, and argue that the spectral variability may be related to geometrical changes of the cold matter which provides a source of seed photons for Comptonization in a hot central disk. One possible configuration is a model with quasi-spherical accretion in the central

Kenji Tomita

Cosmological simulation of gravitational weak lensing in open models is treated using the direct integration method, which is independent of the mult-lens-plane method. Statistical averages of optical quantuties (the convergencen shear and amplification) are derived for ray bundles passing through the clumpy universe, in which the initial state has the CDM s

Shunsuke Hozumi, Lars Hernquist

The influence of central black holes on the dynamical evolution of bars in disk galaxies is examined. In particular, we use numerical simulation to estimate the minimum mass black hole (BH) needed to destroy a bar. Initially, bars form in the disks via dynamical instability. Thereafter, once a bar is fully developed, a BH is adiabatically added at the center

Rosa A. Gonzalez, R. J. Allen, Boris Dirsch, Harry C. Ferguson

We describe a new, direct method for determining the opacity of foreground galaxies which does not require any a priori assumptions about the spatial distribution or the reddening law of the obscuring material. The method is to measure the colors and counts of background galaxies which can be identified through the foreground system. The method is calibrated

Oliver DeWolfe, Tamas Hauer, Amer Iqbal, Barton Zwiebach

BPS states of N=2, D=4 Super Yang-Mills theories with ADE flavor symmetry arise as junctions joining a D3-brane to a set of 7-branes defining the enhanced flavor algebra. We show that the familiar BPS spectrum of SU(2) theories with N_f <= 4 is simply given by the set of junctions whose self-intersection is bounded below as required by supersymmetry. This co

Taekoon Lee, Guo-Hong Wu

The single goldstino interaction is given by the goldstino derivative coupling to the supercurrent. In an alternative description, the goldstino couples nonderivatively. We give a simple method to establish the equivalence of the two approaches, valid to all orders in perturbation theory, and for any scattering process involving an arbitrary number of partic

W. A. Heindl, D. M. Smith

We report on the X-ray spectrum of the 401 Hz X-ray pulsar and type I burst source SAX J1808.4-3658, during its 1998 April/May hard outburst. The observations were made with RXTE over a period of three weeks. The spectrum is well-described by a power law with photon index 1.86+/-0.01 that is exponentially cut off at high energies. Excess soft emission above

M. Koltonyuk, D. Berman, N. B. Zhitenev, R. C. Ashoori

We have incorporated an aluminum single electron transistor (SET) directly on top of a vertical quantum dot, enabling the use of the SET as an electrometer that is extremely responsive to the motion of charge into and out of the dot. Charge induced on the SET central island from single electron additions to the dot modulates the SET output, and we describe t

U. Mohideen, Anushree Roy

We have used an atomic force microscope to make precision measurements of the Casimir force between a metallized sphere of diameter 196 microns and flat plate. The force was measured for plate-sphere separations from 0.1 to 0.9 microns. The experimental results are consistent with present theoretical calculations including the finite conductivity, roughness,

Eugene Demler, Shou-Cheng Zhang

In this work we investigate properties of fermions in the SO(5) theory of high Tc superconductivity. We show that the adiabatic time evolution of a SO(5) superspin vector leads to a non-Abelian SU(2) holonomy of the SO(5) spinor states. Physically, this non-trivial holonomy arises from the non-zero overlap between the SDW and BCS quasi-particle states. While

Steven R. Blusk

In this paper, we report on the most recent measurements of the top quark mass, performed by the CDF and D0 collaborations at the Fermilab Tevatron. The CDF collaboration has performed measurements of the top quark mass in three decay channels from which the top quark mass is measured to be 175.6 +- 6.8 GeV/c^2. The D0 collaboration combines measurements fro

Martin Schmaltz

Starting from Seiberg&#39;s electric-magnetic duality for supersymmetric QCD, we construct dual pairs of non-supersymmetric gauge theories. This is accomplished by first taking the large N limit of supersymmetric QCD and its dual partner and then performing a special ``orbifold projection&#39;&#39; recently introduced by Kachru and Silverstein. We argue that

K. Farakos, G. Koutsoumbas, N. E. Mavromatos

We suggest that a spin-charge separating ansatz, leading to non-Abelian $SU(2) \otimes U_S(1)$ gauge symmetries in doped antiferromagnets, proposed earlier as a way of describing Kosterlitz-Thouless superconducting gaps at the nodes of the gap of d-wave (high-T_c) superconductors, may also lead to a pseudogap phase, characterised by the formation of (non-sup

Adrian Kent

Linden, Massar and Popescu have recently given an optimization argument to show that a single two-qubit Werner state, or any other mixture of the maximally entangled Bell states, cannot be purified by local operations and classical communications. We generalise their result and give a simple explanation. In particular, we show that no purification scheme usi

Igor S. Aranson, Stefan Scheidl, Valerii M. Vinokur

We consider dislocations in a vortex lattice that is driven in a two-dimensional superconductor with random impurities. The structure and dynamics of dislocations is studied in this genuine nonequilibrium situation on the basis of a coarse-grained equation of motion for the displacement field. The presence of dislocations leads to a characteristic anisotropi

V. Dzhunushaliev, D. Singleton

Spherically symmetric, vacuum solutions in 5D and 7D Kaluza-Klein theory are obtained. These solutions are flux tubes with constant cross-sectional size, located between (+) and (-) Kaluza-Klein&#39;s ``electrical&#39;&#39; and ``magnetic&#39;&#39; charges disposed respectively at $\pm\infty$ and filled by constant Kaluza-Klein ``electrical&#39;&#39; and ``m

R. J. Fries, A. Schaefer

We present a calculation of the polarized rho meson cloud in a nucleon using time-ordered perturbation theory in two different variants advocated in the literature. We calculate the induced difference between the distributions Delta d^bar(x) and Delta u^bar(x). We use a recent lattice calculation to motivate an ansatz for the polarized valence quark distribu

Yuval Grossman, Jose R. Pelaez, Mihir P. Worah

$B$ flavor tagging will be extensively studied at the asymmetric $B$ factories due to its importance in CP asymmetry measurements. The primary tagging modes are the semileptonic decays of the $b$ (lepton tag), or the hadronic $b \to c (\to s)$ decays (kaon tag). We suggest that looking for time dependent CP asymmetries in events where one $B$ is tagged lepto

M. Oettel, G. Hellstern, R. Alkofer, H. Reinhardt

The baryon octet and decuplet masses and Bethe-Salpeter vertex and wave functions are calculated in the ladder approximation to the quark exchange between a scalar or axialvector diquark and a constituent quark. These functions reflecting full Lorentz covariance are given in terms of an expansion in Gegenbauer polynomials. In the rest frame of the baryon, a

Sanatan Digal, Rajarshi Ray, Ajit M. Srivastava

We present observations of strength one defects and antidefects formed in isotropic-nematic phase transition in a thin layer of nematic liquid crystals, using a cross-polarizer setup. We measure the widths of the distributions of {\it net} winding number in small regions, and determine the exponent characterizing the correlation between defects and antidefec

Alan Daughton, Jorma Louko, Rafael D Sorkin

We find a number of complex solutions of the Einstein equations in the so-called unimodular version of general relativity, and we interpret them as saddle points yielding estimates of a gravitational path integral over a space of almost everywhere Lorentzian metrics on a spacetime manifold with topology of the &#34;no-boundary&#34; type. In this setting, the

Q. H. Zhang

New type of pion interferometry formulas is derived, in which not only the correlator but also the pion multiplicity is taken consideration. The method to get information about initial emission probability of the unsymmetrized Bosons is given.

L. Fabbian, W. Goetze, F. Sciortino, P. Tartaglia

We calculate the ideal-glass-transition line for adhesive hard spheres in the temperature-volume-fraction plane within the framework of the mode-coupling theory. We find two intersecting lines, controlled by the hard-core and the adhesive part of the potential respectively, giving rise to two different mechanisms for structural arrest. In the glass region we

B. Mele, S. Petrarca, A. Soddu

We present a new calculation of the t->cH decay rate in the standard model. We find that the corresponding branching fraction is B(t->cH) \sim 10^{-13} - 10^{-14} for M_Z < m_H < 2 M_W, that is about 6 orders of magnitude less than previously evaluated, and usually quoted in the literature.

Takeshi Sato

We derive the spacetime superalgebras explicitly from ``test&#39;&#39; p-brane actions in a D-8-brane (i.e. a massive IIA) background to the lowest order in $θ$ via canonical formalism, and show that the forms of the superalgebras are the same as those in all the other D-brane (i.e. massless IIA) backgrounds, that is, they are indifferent to the presence of

V. Yu. Irkhin, M. I. Katsnelson

The lowest-order scaling consideration of the magnetic state formation in the Kondo lattices is performed within the $s-f$ model with inclusion of anisotropy for both the $f-f$ coupling and $s-f$ exchange interaction. The Kondo renormalizations of the effective transverse and longitudinal $s-f$ coupling parameters, spin-wave frequency, gap in the magnon spec

Gabor Csanyi, T. A. Arias

We explore a new class of computationally feasible approximations of the two-body density matrix as a finite sum of tensor products of single-particle operators. Physical symmetries then uniquely determine the two-body matrix in terms of the one-body matrix. Representing dynamical correlation alone as a single tensor product results in a theory which predict

Viqar Husain

We give ansatze for solving classically the initial value constraints of general relativity minimally coupled to a scalar field, electromagnetism or Yang-Mills theory. The results include both time-symmetric and asymmetric data. The time-asymmetric examples are used to test Penrose&#39;s cosmic censorship inequality. We find that the inequality can be violat

M. Blanton, E. L. Turner, J. Wambsganss

We analyze observations of the quadruple lensed quasar Q2237+0305, taken with the WFPC2 camera in the F336W and F300W bands. 25 exposures were performed within 15 hours real time on 3 November 1995. On a timescale of 3--4 hours, we observe no variation in component A of greater than 0.02 mag. The other components are constant over a period of 10 hours to wit

Boris G. Konopelchenko, Luis Martinez Alonso, Elena Medina

Integrable hierarchies associated with the singular sector of the KP hierarchy, or equivalently, with $\dbar$-operators of non-zero index are studied. They arise as the restriction of the standard KP hierarchy to submanifols of finite codimension in the space of independent variables. For higher $\dbar$-index these hierarchies represent themselves families o

R. Milson, D. Richter

The space of realizations of a finite-dimensional Lie algebra by first order differential operators is naturally isomorphic to H^1 with coefficients in the module of functions. The condition that a realization admits a finite-dimensional invariant subspace of functions seems to act as a kind of quantization condition on this H^1. It was known that this quant

E. Persson, K. Pichugin, I. Rotter, P. Seba

We present a method for numerically obtaining the positions, widths and wavefunctions of resonance states in a two dimensional billiard connected to a waveguide. For a rectangular billiard, we study the dynamics of three resonance poles lying separated from the other ones. As a function of increasing coupling strength between the waveguide and the billiard t

Richard Jozsa

We discuss some seemingly paradoxical yet valid effects of quantum physics in information processing. Firstly, we argue that the act of ``doing nothing&#39;&#39; on part of an entangled quantum system is a highly non-trivial operation and that it is the essential ingredient underlying the computational speedup in the known quantum algorithms. Secondly, we sh

Francesco Cannata, Georg Junker, Johannes Trost

Several aspects of complex-valued potentials generating a real and positive spectrum are discussed. In particular, we construct complex-valued potentials whose corresponding Schrödinger eigenvalue problem can be solved analytically.

Peter Horak, Jean-Yves Courtois, Gilbert Grynberg

We demonstrate the possibility of three-dimensional cooling of neutral atoms by illuminating them with two counterpropagating laser beams of mutually orthogonal linear polarization, where one of the lasers is a speckle field, i.e. a highly disordered but stationary coherent light field. This configuration gives rise to atom cooling in the transverse plane vi

Thomas Mahr, Ingo Rehberg

Observations of parametrically excited surface waves in a magnetic fluid are presented. Under the influence of a magnetic field these waves have a non--monotonic dispersion relation, which leads to a richer behavior than in ordinary liquids. We report observation of three novel effects, namely: i) domain structures, ii) oscillating defects and iii) relaxatio

Thomas Mahr, Ingo Rehberg

In a magnetic fluid parametrically driven surface waves can be excited by an external oscillating magnetic field. A static magnetic field changes the restoring forces and damping coefficients of the various surface waves. This property enables the excitation of both subharmonic and harmonic responses of the standing waves.

Carlos A. Bertulani

We study the breakup of 9Li projectiles in high energy (28.5 MeV/u) collisions with heavy nuclear targets (208Pb). The wave functions are calculated using a single-particle model for 9Li, and a simple optical potential model for the scattering part. A good agreement with measured data is obtained with insignificant E2 contribution.

John W. Norbury, Marsha L. Waldsmith

The effects of higher order corrections in ultra-relativistic nuclear collisions are considered. It is found that higher order contributions are small at low energy, large at intermediate energy and small again at very high energy. An explanation for this effect is given. This means that the Weizsacker-Williams formula is a good approximation to use in calcu

Tomoko Asaga, Takehisa Fujita, Makoto Hiramoto

We study the hyperfine splitting of an electron in hydrogen-like $^{209}Bi ^{82+} $. It is found that the hfs energy splitting can be explained well by considering the g-factor reduction due to the binding effect of a bound electron. We determine for the first time the experimental value of the magnetic moment of a tightly bound electron.

Oliver Schnetz

A formula is derived that provides generating functions for any multi-j-symbol, such as the 3-j-symbol, the 6-j-symbol, the 9-j-symbol, etc. The result is completely determined by geometrical objects (loops and curves) in the graph of the the multi-j-symbol. A geometric-combinatorical interpretation for multi-j-symbols is given.

Palle E. T. Jorgensen

Let $ N \in \mathbb{N} $, $ N \geq 2 $, be given. Motivated by wavelet analysis, we consider a class of normal representations of the $ C^* $-algebra $ \mathfrak{A}_{N} $ on two unitary generators $ U $, $ V $ subject to the relation \[ UVU^{-1}=V^{N}. \] The representations are in one-to-one correspondence with solutions $ h \in L^{1}(\mathbb{T}) $, $ h \ge

Axel Schueler

Let A be a Hopf algebra and $Gamma$ be a bicovariant first order differential calculus over A. It is known that there are three possibilities to construct a differential Hopf algebra $Gamma^wedge$ that contains $Gamma$ as its first order part; namely the universal exterior algebra, the second antisymmetrizer exterior algebra, and Woronowicz&#39; external alg

Gary McCartor

I argue that for the case of fermions with nonzero bare mass there is a term in the matter density operator in the light-cone representation which has been omitted from previous calculations. The new term provides agreement with previous results in the equal-time representation for mass perturbation theory in the massive Schwinger model. For the DLCQ case th

R. Kallosh, J. Rahmfeld, A. Rajaraman

The adS_{p+2} x S^{d-p-2} geometry of the near horizon branes is promoted to a supergeometry: the solution of the supergravity constraints for the vielbein, connection and form superfields are found. This supergeometry can be used for the construction of new superconformal theories. We also discuss the Green-Schwarz action for a type IIB string on adS_5 x S_

Michael Lashkevich, Yaroslav Pugai

The nearest neighbor two-point correlation function of the $Z$-invariant inhomogeneous eight-vertex model in the thermodynamic limit is computed using the free field representation.

Uwe Mueller, Gerhard Weigt

We prove that any gauged WZNW model has a Lax pair representation, and give explicitly the general solution of the classical equations of motion of the SL(2,R)/U(1) theory. We calculate the symplectic structure of this solution by solving a differential equation of the Gelfand-Dikii type with initial state conditions at infinity, and transform the canonical

Sicong Jing, Charles A. Nelson

The structure of the state-vector space for the two-mode parabose system is investigated and a complete set of state-vectors is constructed. The basis vectors are orthonormal in order $p=2$. In order $p=2$, conserved-charge parabose coherent states are constructed and an explicit completeness relation is obtained.

Cumrun Vafa

We review some aspects of minimal cycles in string compactifications and their role in constructing new critical theories in six and lower dimensions as well as in accounting for black hole entropy. (Based on a talk presented at the Salam Memorial Meeting, the Abdus Salam International Center for Theoretical Physics, Fall 1997)

J. Ambjørn, L. Chekhov

We investigate the NBI matrix model with the potential $XΛ+X^{-1}+(2η+1)\log X$ recently proposed to describe IIB superstrings. With the proper normalization, using Virasoro constraints, we prove the equivalence of this model and the Kontsevich matrix model for $η\ne0$ and find the explicit transformation between the two models.

Sebastian Jaimungal

It is shown that when the underlying sigma model of bosonic string theory is written in terms of single-valued fields, which live in the covering space of the target space, Abelian T-duality survives lattice regularization of the world-sheet. The projection onto the target-space is implemented through a sum over cohomology, which bears resemblance to summing

B. Delamotte, D. Mouhanna, P. Lecheminant

We study the Principal Chiral Ginzburg-Landau-Wilson model around two dimensions within the Local Potential Approximation of an Exact Renormalization Group equation. This model, relevant for the long distance physics of classical frustrated spin systems, exhibits a fixed point of the same universality class that the corresponding Non-Linear Sigma model. This

Aleksey Nudelman

We study scattering of $D0$ branes in eleven dimensional supergravity (SUGRA) using the tree level four point amplitude. The range of validity of SUGRA allows us to make reliable calculations of relativistic brane scattering, inaccessible in string theory because of halo effects. We also compare the rate of annihilation of $D0-\bar{D0}$ branes to the rate of

Otto C. W. Kong, Feng-Li Lin

We discuss the feasibility of spontaneous CP violation being induced by radiative corrections in 2HDM&#39;s. Specifically, we analyze the cases of gaugino/higgsino effect on MSSM, and a new model with an extra exotic quark doublet. The new model, while demonstrating well the Georgi-Pais theorem, is also expected to be phenomenlogically interesting.

Howard Georgi, Jihn E. Kim, Hans-Peter Nilles

In the effective field theory framework, we consider the effect of supersymmetry breaking via gaugino condensation and supergravity in the hidden sector gauge group on the hidden sector vacuum angle $θ_h$. The $θ_h$ parameter dependence of the potential yields phenomenologically acceptable invisible axion solutions if the $U(1)_R$ symmetry is broken down to

A. C. Melissinos

We discuss the spontaneous breakdown of the vacuum by a strong electromagnetic field as observed in SLAC experiment E-144. We show that the data follow the Schwinger non-perturbative result obtained for a static field.

A. C. Melissinos

We consider axion production during the formation of a quark-gluon plasma in relativistic heavy-ion collisions and discuss a possible detection scheme.

Valery A. Khoze

I will attempt to survey some selected physics issues on QCD interconnection phenomena in the processes $e^+e^-\to W^+W^-\to$ 4 jets and $e^+e^-\to t\bar t \to b W^+\bar b W^-$. Possible consequences for LEP2 and future linear $e^+e^-$ colliders are briefly discussed.

Marco Genovese

In this paper I review the theoretical progresses in studying the diffractive DIS in the colour--dipole approach.

Christopher Balzereit

We complete the one loop renormalization of the HQET lagrangian at O(1/m_Q^3) including four fermion operators with two heavy and two light quark fields in the operator basis. It is shown that as a consequence the short distance coefficients of the operators bilinear in the heavy quark field receive nontrivial corrections.

Nita Sinha, Rahul Sinha

We present a technique to determine the CP violating phases, as well as, the lifetime differences of the mass eigenstates for both $B_d$ and $B_s$, by considering correlated $B\bar{B}$ pairs produced at the $Υ$ resonances. We do not require a detailed time dependent study, but only partial time integrated rates, with the tag time, either preceding or followi