arXiv papers from April 1998

Don N. Page

The capture or scattering of an initially straight infinite test cosmic string by a Kerr-Newman black hole, or by any other small source of an electrovac gravitational field, is analyzed analytically when the string moves with initial velocity v and large impact parameter b >> M so that the string stays very nearly straight (except during the final capture p

A. I. Buzdin, A. A. Varlamov

The fit of the experimental data on c-axis magnetoresistance of HTS above the transition temperature with the theory based on the fluctuation renormalization of the one-electron density of states (DOS) is exellent in weak magnetic fields but meets the noticible difficulties in the region of strong fields. This is due to the formal divergency of the DOS contr

D. E. MacLaughlin, R. H. Heffner, G. J. Nieuwenhuys, G. M. Luke

Muon spin rotation experiments on a stoichiometric sample of the non-Fermi liquid (NFL) heavy-fermion compound UCu_4Pd, in which recent neutron Bragg scattering measurements are consistent with an ordered structure, indicate that the U-ion susceptibility is strongly inhomogeneous at low temperatures. This suggests that residual disorder dominates NFL behavio

A. E. Carlsson

Quantum-mechanical analysis based on an exact sum rule is used to extract an semiclassical angle-dependent energy function for transition metal ions in biomolecules. The angular dependence is simple but different from existing classical potentials. Comparison of predicted energies with a computer-generated database shows that the semiclassical energy functio

U. F. Wichoski, Jane H. MacGibbon, Robert H. Brandenberger

Primordial Black Holes (PBH) may have formed from the collapse of cosmic string loops. The spectral shape of the PBH mass spectrum can be determined by the scaling argument for string networks. Limits on the spectral amplitude derived from extragalactic gamma-ray and galactic gamma-ray and cosmic ray flux observations as well as constraints from the possible

R. D. Pisarski, T. L. Trueman, M. H. G. Tytgat

I review the implications of the axial anomaly in a thermal bath. I assume that the Adler-Bardeen theorem applies at nonzero temperature, so that the divergence of the axial current remains is independent of temperature. Nevertheless, I argue that while the anomaly doesn't change with temperature, ``anomalous'' mesonic couplings do. This is verified by expli

A. Jevicki, M. Mihailescu, J. P. Nunes

We review some aspects of the construction of self-dual gravity and the associated field theory of ${\cal N}=2$ strings in terms of two-dimensional sigma models at large $N$. The theory is defined through a large $N$ Wess-Zumino-Witten model in a nontrivial background and in a particular double scaling limit. We examine the canonical structure of the theory

Jean-Pierre De Villiers, Valeri Frolov

The scattering of a straight, infinitely long string moving with velocity $v$ by a black hole is considered. We analyze the weak-field case, where the impact parameter ($b_{imp}$) is large, and obtain exact solutions to the equations of motion. As a result of scattering, the string is displaced in the direction perpendicular to the velocity by an amount $\De

Oliver DeWolfe, Barton Zwiebach

We consider string junctions with endpoints on a set of branes of IIB string theory defining an ADE-type gauge Lie algebra. We show how to characterize uniquely equivalence classes of junctions related by string/brane crossing through invariant charges that count the effective number of prongs ending on each brane. Each equivalence class defines a point on a

L. Burakovsky

We show that linear Regge trajectories for mesons and glueballs, and the cubic mass spectrum associated with them, determine a relation between the masses of the \rho meson and the scalar glueball, M(0^{++})=3/\sqrt{2} M(\rho ), which implies M(0^{++})=1620\pm 10 MeV. We also discuss relations between the masses of the scalar and tensor and 3^{--} glueballs,

M. Maltoni, M. I. Vysotsky

We show that recently announced strong bound on $\mu_{\nu_\tau}$ can not be justified, and confirm original L3 result.

Inyong Cho

Inflation of cosmic gauge and global strings is investigated by numerically solving the combined Einstein and field equations. Above some critical symmetry-breaking scales, the strings undergo inflation along the radial direction as well as the axial direction at the core. The nonsingular nature of the spacetimes around supercritical gauge and global strings

C. S. Lam

An attempt is made in QCD to explain the growth of total cross-sections with energy, without violating the Froissart bound. This is achieved by computing the phase shifts of elastic scatterings of partons rather than their amplitudes. To render that possible a general formalism of phase-shifts in QCD is developed. Computed to two-loop order, agreements with

Huai-Dong Cao, Jian Zhou

We define quantum exterior product wedge_h and quantum exterior differential d_h on Poisson manifolds (of which symplectic manifolds are an important class of examples). Quantum de Rham cohomology, which is a deformation quantization of de Rham cohomology, is defined as the cohomology of d_h. We also define quantum Dolbeault cohomology. A version of quantum

Catherine Crawford, Hermann Riecke

Motivated by the observation of localized circular excitations (`oscillons') in vertically vibrated granular layers (P.B. Umbanhowar, F. Melo and H.L. Swinney, Nature 382 (1996) 793), we numerically investigate an extension of a Swift-Hohenberg model that exhibits a subcritical transition to square patterns. For sufficient subcriticality, stable oscillon str

J. G. Russo

A one-parameter family of new solutions representing Einstein spaces in $d=5,7$ is presented, and used to construct non-supersymmetric backgrounds in type IIB and M-theory that asymptotically approach $AdS_5\times S^5$ and $AdS_7\times S^4$ . Upon dimensional reduction, the latter gives a type IIA solution representing a 4-brane with Ramond-Ramond charge, wh

Beverly K. Berger, Vincent Moncrief

A longstanding conjecture by Belinskii, Lifshitz, and Khalatnikov that the singularity in generic gravitational collapse is locally oscillatory is tested numerically in vacuum, U(1) symmetric cosmological spacetimes on $T^3 \times R$. If the velocity term dominated (VTD) solution to Einstein's equations is substituted into the Hamiltonian for the full Einste

Martin B. Plenio, Vlatko Vedral

Quantum mechanics has many counter-intuitive consequences which contradict our intuition which is based on classical physics. Here we discuss a special aspect of quantum mechanics, namely the possibility of entanglement between two or more particles. We will establish the basic properties of entanglement using quantum state teleportation. These principles wi

Atish Dabholkar

This is an introduction to orientifolds with emphasis on applications to duality. Based on lectures given at the 1997 Trieste Summer School on Particle Physics and Cosmology, Italy.

Antonio Pich, Joaquim Prades

The perturbative quark-mass corrections to the $\tau$ hadronic width are analysed to $O(\alpha_s^3 m_q^2)$, using the presently available theoretical information. The behaviour of the perturbative series is investigated in order to assess the associated uncertainties. The implications for the determination of the strange quark mass from $\tau$ decay data are

Antun Balaz, Aleksandar Belic, Aleksandar Bogojevic

We present a new approximation technique for quantum field theory. The standard one-loop result is used as a seed for a recursive formula that gives a sequence of improved Gaussian approximations for the generating functional. In a different setting, the basic idea of this recursive scheme is used in the second part of the paper to substantialy speed up the

Xiaotong Song

Using the unified scheme for describing both quark spin and orbital angular momenta in the chiral quark model developed in the previous work, the magnetic moments of octet and decuplet baryons are calculated. The numerical result shows that the overall agreement with data is improved by including the orbital contributions.

Paolo Gondolo, Joakim Edsjo

We enlarge our set of supersymmetric models and update accelerator constraints in our precise calculation of the relic density of the lightest neutralino, which includes relativistic Boltzmann averaging, subthreshold and resonant annihilations, and coannihilation processes among charginos and neutralinos.

B. G. Konopelchenko, G. Landolfi

Generalizations of the Weierstrass formulae to generic surface immersed into $R^4$, $S^4$ and into multidimensional Riemann spaces are proposed. Integrable deformations of surfaces in these spaces via the modified Veselov-Novikov equation are discussed.

Alistair R. Walker

The variable star population of the galactic globular cluster NGC 1851 (C0512-400) has been studied by CCD photometry, from observations made in the B, V, and I bands during 1993-4. Light curves are presented for 29 variables, seven of which are new discoveries. The behavior of the RR lyraes in the period-temperature diagram appears normal when compared to c

Yutaka Hosotani, Ramon Rodriguez

The massive N-flavor Schwinger model is analyzed by the bosonization method. The problem is reduced to the quantum mechanics of N degrees of freedom in which the potential needs to be self-consistently determined by its ground-state wave function and spectrum with given values of the $\theta$ parameter, fermion masses, and temperature. Boson masses and fermi

H. W. Braden, V. Varela

We derive Bogomolny equations for an Einstein-Yang-Mills-dilaton-$\sigma$ model (EYMD-$\sigma$) on a static spacetime, showing that the Einstein equations are satisfied if and only if the associated (conformally scaled) three-metric is flat. These are precisely the static metrics for which super-covariantly constant spinors exist. We study some general prope

T. Venturi, S. Bardelli, R. Morganti, R. W. Hunstead

In this paper we present a detailed study of the radio galaxy J1324-3138, located at a projected distance of 2 arcmin from the centre of the Abell cluster of galaxies A3556, belonging to the core of the Shapley Concentration, at an average redshift z=0.05. We have observed J1324-3138 over a wide range of frequencies: at 327 MHz (VLA), at 843 MHz (MOST), and

A. P. Whitworth, H. M. J. Boffin, N. Francis

We suggest that the abrupt switch, from hierarchical clustering on scales larger than 0.04 pc, to binary (and occasionally higher multiple) systems on smaller scales, which Larson has deduced from his analysis of the grouping of pre-Main-Sequence stars in Taurus, arises because pre-protostellar gas becomes thermally coupled to dust at sufficiently high densi

M. Cencini, M. Falcioni, D. Vergni, A. Vulpiani

We study the coherent dynamics of globally coupled maps showing macroscopic chaos. With this term we indicate the hydrodynamical-like irregular behaviour of some global observables, with typical times much longer than the times related to the evolution of the single (or microscopic) elements of the system. The usual Lyapunov exponent is not able to capture t

Marcelo Botta Cantcheff

In order to obtain a well defined quantum gravity we define the spacetime in relation to the "phenomenology" of the physical interactions; however we shall to speculate with this "in General". Besides, we comment the reasons that give to the gravitational field a privilegied situation over the others.

R. de Grijs

A statistical study of global galaxy parameters can help to improve our understanding of galaxy formation processes. In this paper we present the analysis of global galaxy parameters based on optical and near-infrared observations of a large sample of edge-on disc galaxies. We found a correlation between the ratio of the radial to vertical scale parameter an

Philip D. Mannheim

In this paper we present a general, model independent analysis of a recently detected apparent cosmic repulsion, and discuss its potential implications for gravitational theory. In particular, we show that a negatively spatially curved universe acts like a diverging refractive medium, to thus naturally cause galaxies to accelerate away from each other. Addit

Giovanni Gallavotti

On the occasion of the 40-th anniversary of IHES I present a few scientific reminiscences: most of my scientific life has been marked by my visits and I run through them concluding with the analysis of a problem that originated during my last visit. The problem is to develop a convergent perturbative algorithm for the construction of the ``Eliasson's potenti

Frank Eberlein

One-loop gap equations have recently been used by several authors to estimate the non-perturbative mass gap in a 3-dimensional gauge theory. I extend the method to two loops and demonstrate, that the resulting gap equation has a real and positive solution $m \simeq 0.34 g^2$, which is in good agreement with the one-loop results and lattice data.

Panagiota Kanti

In this talk, we recall the most important features of the Dilatonic Black Holes which arise in the framework of the Einstein-Dilaton-Gauss-Bonnet theory and which are dressed with a classical long range dilaton field in contradiction with the existing "no-hair" theorems of the Theory of General Relativity. We demonstrate linear stability of these black hole

Lj. Simic, M. Kornicer

The shape of proton rapidity distributions is analysed in terms of their Gaussian components, and the average rapidity loss is determined in order to estimate the amount of stopping in C+C, d+C, C+Ta and d+Ta collisions at 4.2A GeV/c. Three Gaussians correspond to the nuclear transparency and describe well all peripheral and also C+C central collisions. Two-

I. M. Hook, R. H. Becker, R. G. McMahon, R. L. White

We present the method and first results of a survey for high-redshift (z>3) radio-loud quasars, which is based on optical identifications of 2902 flat-spectrum radio sources with S(5GHz)>= 25mJy. The radio sample was defined over a 1600 sq degree region using the 5GHz Green Bank survey and the 1.4GHz VLA FIRST survey. 560 sources were identified to a limit o

Paolo Bellomo, C. R. Stroud,

We study the dispersion of the "temporally stable" coherent states for the hydrogen atom introduced by Klauder. These are states which under temporal evolution by the hydrogen atom Hamiltonian retain their coherence properties. We show that in the hydrogen atom such wave packets do not move quasi-classically; i.e., they do not follow with no or little disper

M. J. Coe, S. L. Pightling

Deep infrared and optical images are presented of three proposed remnants of Thorne-Zytkow Objects (TZO). In particular, the IR data go several infrared magnitudes deeper than previous observations and in at least one case reveal the existence of weak objects within the error circles. It is argued, however, that none of the objects is likely to be the binary

T. M. Aliev, C. S. Kim, M. Savci

We examine the possibility for precise determination of |V_{ts}| (and |V_{td}/V_{ts}|) from the exclusive decays, $B --> K \ell^+ \ell^-, B --> K^* \ell^+ \ell^-$ (and $B --> \pi \ell^+ \ell^-, B --> \rho \ell^+ \ell^-$). We show that the ratio |V_{ts}| can be extracted experimentally with a small theoretical uncertainty from hadronic form--factors, if we {\

Maja Buric, Voja Radovanovic, Aleksandar Mikovic

We study quantum corrections for the Schwarzshild black hole by considering it as a vacuum solution of a 2D dilaton gravity theory obtained by spherical reduction of 4D gravity coupled with matter. We find perturbatively the vacuum solution for the standard one-loop effective action in the case of null-dust matter and in the case of minimally coupled scalar

D. Drechsel, G. Knoechlein, A. Yu. Korchin, A. Metz

We perform an expansion of the virtual Compton scattering amplitude for low energies and low momenta and show that this expansion covers the transition from the regime to be investigated in the scheduled photon electroproduction experiments to the real Compton scattering regime. We discuss the relation of the generalized polarizabilities of virtual Compton s

C. Beck, Sl. Cavallaro, R. Dayras

Fusion-fission and fully energy-damped binary processes of the $^{35}$Cl+$^{24}$Mg reaction were investigated using particle-particle coincidence techniques at a $^{35}$Cl bombarding energy of E$_{lab}$ $\approx$ 8 MeV/nucleon. Inclusive data were also taken in order to determine the partial wave distribution of the fusion process. The fragment-fragment corr

G. Gallavotti, G. Gentile, V. Mastropietro

We continue a previous paper to show that Mel'nikov's first order formula for part of the separatrix splitting of a pendulum under fast quasi periodic forcing holds, in special examples, as an asymptotic formula in the forcing rapidity.

T. E. Browder

We report the first observation of $B\to \eta' X$ transitions with high momentum $\eta'$ mesons. We observe $39.0\pm 11.6$ B decay events with $2.0< p_{\eta'} < 2.7$ GeV/c, the high momentum region where background from $b\to c$ processes is suppressed. We discuss the physical interpretation of the signal, including the possibility that it is due to $b\to s

Abhishek Dhar

A single spin flip stochastic energy conserving dynamics for the XY model is considered. We study the ergodicity properties of the dynamics. It is shown that phase space trajectories densely fill the geometrically connected parts of the energy surface. We also show that while the dynamics is discrete and the phase point jumps around, it cannot make transitio

F. M. Nunes, I. J. Thompson

The breakup of $^8$B on $^{58}$Ni below the Coulomb barrier was measured recently with the aim of determining the Coulomb breakup components. We reexamine this reaction, and perform one step quantum-mechanical calculations that include E1, E2 and nuclear contributions. We show that the nuclear contribution is by no means negligible at the intermediate angula

Heinz Rupertsberger

Within Bohm`s interpretation of quantum mechanics particles follow classical trajectories that are determined by the full solution of the time dependent Schroedinger equation. If this interpretation is consistent it must be possible to determine the probability distribution at time t from the probability distribution at time t=0 by using these trajectories.

I. M. Barbour, N. Psycharis, E. Focht, W. Franzki

We investigate the critical behaviour of a three-dimensional lattice $\chiU\phi_3$ model in the chiral limit. The model consists of a staggered fermion field, a U(1) gauge field (with coupling parameter $\beta$) and a complex scalar field (with hopping parameter $\kappa$). Two different methods are used: 1) fits of the chiral condensate and the mass of the n

Konrad Schmuedgen

Let A be a coquasitriangular Hopf algebra and X the subalgebra of A generated by a row of a matrix corepresentation u or by a row of u and a row of the contragredient representation u^c. In the paper left-covariant first order differential calculi on the quantum group A are constructed and the corresponding induced calculi on the left quantum space X are des

Ye. M. Hakobyan, G. S. Pogosyan, A. N. Sissakian

This article deals with nonrelativistic study of a D-dimensional superintegrable system, which generalizes the ordinary isotropic oscillator system. The coefficients for the expansion between the hyperspherical and Cartesian bases (transition matrix), and vice-versa, are found in terms of the SU(2) Clebsch--Gordan coefficients analytically continued to real

Bernhard Schmidt

The Inner Tracker System of the HERA-B experiment at DESY consists of 184 Microstrip Gas Chambers (MSGC) with a total number of 147 456 electronic read out channels. The detectors have to cope with particle fluxes up to 25 kHz/mm**2 and to tolerate radiation doses of 1 Mrad per year. During the development of these chambers it was found that conventional MSG

Pavel Katsylo

We construct the canonical structure of an irreducible projective variety on the set of connected curves of degree $d$ in $\Bbb P^n$ with rational components (some components can be multiple). The set of rational curves is open subset in the Zariski topology under this structure.

Z. Neda, R. Florian

We discuss a classical mistake, made in earlier publications on the stick percolation problem in 3D, for generating the right isotropic configuration of sticks. We explain the observed systematic deviations from the excluded volume rule. New MC simulations considered by us confirm nicely the applicability of the excluded volume theory.

Vassil Kanev

It is proved that the chordal variety of the Veronese variety v_d(P^n) is projectively normal, arithmetically Cohen-Macaulay and its homogeneous ideal is generated by the 3 x 3 minors of two catalecticant matrices. These results are generalized to the catalecticant varieties Gor_{\leq}(T) with t_1 = 2. We also give a simplified proof of a theorem of O. Porra

J. Gorosabel, A. J. Castro-Tirado, C. J. Willott, H. Hippelein

We report the detection of the GRB 971214 counterpart in the near-infrared by means of two images in the K'-band taken at Calar Alto only ~3.5 and ~5 hours after the gamma-ray event. We detect the transient at K'=18.03+/-0.18 and K'=18.00+/-0.22 respectively. Our data seem to indicate the existence of a plateau with duration ~1.5 < T < 6.7 hours (between 3.5

T. M. Aliev, E. O. Iltan

We study the decay width, forward-backward asymmetry and the longitudinal lepton polarization for the exclusive decay B --> K^* l^+ l^- in the two Higgs doublet model with three level flavor changing neutral currents (model III) and analyse the dependencies of these quantities on the the selected parameters, \xi^{U,D}, of model III including the next to lead

A. V. Soroko

Raman cooling of non-zero-spin atoms in the presence of gravitational and external magnetic fields is investigated. The magnetic field is adjusted so as to compensate for the gravitational force acting on ground-state atoms. The dark state (DS) is created and supported in momentum space with additional velocity-selective two-photon transitions. The minimum a

S. Rosswog, F. -K. Thielemann, M. B. Davies, W. Benz

Recent calculations place questions on the ability of supernovae to produce r-process nuclei in the correct amounts. We present results from 3D Newtonian SPH calculations of mergers of equal mass neutron star binaries. We find the amounts of ejected mass to be very promising for an explanation of the observed r-process abundances. Preliminary abundance calcu

Alexander K. Hartmann

Ground states of 3d EA Ising spin glasses are calculated for sizes up to 14^3 using a combination of a genetic algorithm and Cluster-Exact Approximation. Evidence for an ultrametric structure is found by studying triplets of independent ground states where one or two values of the three overlaps are fixed.

J. G. Bartlett, P. Amram

We review present understanding of Galactic free-free emission and its possible importance to CMB fluctuation measurements. Current results, from both ``direct'' observations in the microwave band and from H$\alpha$ studies, suggest that this foreground does not represent a serious obstacle to mapping the CMB; however, this is based on limited information an

Marcus Metzler, Imre Varga

We numerically investigate the spectral statistics of pseudo-energies for the unitary network operator U of the Chalker--Coddington network. The shape of the level spacing distribution as well the scaling of its moments is compared to known results for quantum Hall systems. We also discuss the influence of multifractality on the tail of the spacing distribut

Mayumi Aoki, Noriyuki Oshimo, Akio Sugamoto

Baryon asymmetry of the universe can be generated by new sources of $CP$ violation intrinsic in supersymmetric extension of the standard model. This scenario predicts the neutron electric dipole moment to be not much smaller than its present experimental upper bound.

E. A. Moukhai, V. A. Rodin, M. H. Urin

A semimicroscopical approach is applied to calculate: (i) strength functions for the charge-exchange spin-dipole giant resonances in the 208Pb parent nucleus; (ii) partial and total branching ratios for the direct proton decay of the resonance in 208Bi. The approach is based on continuum-RPA calculations of corresponding reaction-amplitudes and phenomenologi

Takeshi Sato

We derive the spacetime superalgebras explicitly from ``test'' M-brane actions in M-brane backgrounds to the lowest order in $\theta$ via canonical formalism, and discuss various BPS saturated configurations on the basis of their central charges which depend on the harmonic functions determined by the backgrounds. All the 1/4 supersymmetric intersections of

Seungho Choe

The coupling constants g_{\pi \Lambda \Sigma} and g_{K \Sigma \Xi} are calculated in the QCD sum rule approach using the three-point function method and taking into account the SU(3) symmetry breaking effects. The pattern of SU(3) breaking appears to be different from that based on SU(3) relations.

Clifford V. Johnson

In SO(32) heterotic string theory, the space-time at the core of N coincident NS-fivebranes is an infinite throat, R x S^3. As shown by Witten, the throat signals a singularity in the usual heterotic string conformal field theory and a non--perturbative USp(2N) gauge group appears, due to the N small instantons at the fivebranes' core. Nevertheless, we look

Clifford V. Johnson

We study the origins of the five ten-dimensional ``matrix superstring'' theories, supplementing old results with new ones, and find that they all fit into a unified framework. In all cases the matrix definition of the string in the limit of vanishingly small coupling is a trivial 1+1 dimensional infra-red fixed point (an orbifold conformal field theory) char

Fenghua Zong, D. M. Ceperley

We describe a method to evaluate electronic forces by Path Integral Monte Carlo (PIMC). Electronic correlations, as well as thermal effects, are included naturally in this method. For fermions, a restricted approach is used to avoid the ``sign'' problem. The PIMC force estimator is local and has a finite variance. We applied this method to determine the bond

Seungwon Baek, P. Ko, Jungil Lee, H. S. Song

Polarizations of the prompt $J/\psi$'s produced in the $e^+e^-$ annihilation at CLEO energy ($\sqrt{s} = 10.58$ GeV) are considered in the framework of NRQCD factorization formalism. We find that the $J/\psi$ polarization has strong dependence on the production mechanism. At CLEO energy, the most dominant $J/\psi$ production mechanism in the most phase space

Davison E. Soper

Calculations of observables in Quantum Chromodynamics are typically performed using a method that combines numerical integrations over the momenta of final state particles with analytical integrations over the momenta of virtual particles. I discuss a method for performing all of the integrations numerically.

Werner Krauth, Matthias Staudacher

We use Monte Carlo methods to directly evaluate D-dimensional SU(N) Yang-Mills partition functions reduced to zero Euclidean dimensions, with and without supersymmetry. In the non-supersymmetric case, we find that the integrals exist for D=3, N>3 and D=4, N>2 and, lastly, D >= 5, N >= 2. We conclude that the D=3 and D=4 integrals exist in the large N limit,

Bruce A. Bassett, Fabrizio Tamburini

Grand unified theories may display multiply interacting fields with strong coupling dynamics. This poses two new problems: (1) What is the nature of chaotic reheating after inflation, and (2) How is reheating sensitive to the mass spectrum of these theories ? We answer these questions in two interesting limiting cases and demonstrate an increased efficiency

R. Torrealba

In this work we present a proof of the discreteness of the spectrum for bosonic membrane, in a flat minkowski space. This may be useful to show the quantum mechanical consistence of others bosonics extended models. This proof includes the BRST residual symmetry and was directly performed over the discretized membrane model. The BRST residual invariant effect

Matthias Eschrig

We use the quasiclassical theory of superconductivity to calculate the response of the currents in the core of a vortex to an alternating electric field. We consider relatively clean superconductors with a mean free path larger than the coherence length (but still not in the &#39;superclean limit&#39;). The current response of the core is dominated by the bo

Lev P. Gor`kov, Vladimir Z. Kresin

A tight-band model is employed for the $e_{2g}$-orbitals in manganites. It is shown that a large intraatomic Hund&#39;s coupling, $J_H$ and the resulting double-exchange mechanism lead to antiferromagnetic ordering along one of the cubic axis stabilized by the cooperative JT effect which further decreases the band energy of electrons. As a result, LaMnO$_3$

M. Franz, Z. Tešanović

We investigate quasiparticle states associated with an isolated vortex in a d-wave superconductor using a self-consistent Bogoliubov-de Gennes formalism. For a pure $d_{x^2-y^2}$ superconductor we find that there exist no bound states in the core; all the states are extended with continuous energy spectrum. This result is inconsistent with the existing exper

N. C. A. da Costa, F. A. Doria

We investigate the existence of a class of ZFC-provably total recursive unary functions, given certain constraints, and apply some of those results to show that, for $Σ_1$-sound set theory, ZFC$\not\vdash P<NP$.

Ata Sarajedini

In the process of searching the Hubble Space Telescope archive, we have serendipitously discovered three populous Large Magellanic Cloud (LMC) clusters with ages that place them in the LMC `age gap.&#39;. These clusters - NGC 2155, SL663, and NGC 2121 - turn out to have [Fe/H] ~ -1.0 and ages of ~4 Gyr. This puts them in the age gap between the intermediate-

W. J. G. de Blok, J. M. van der Hulst

We present deep, pointed $^{12}$CO($J=2-1$) observations of three late-type LSB galaxies. The beam-size was small enough that we could probe different environments (\HI maximum, \HI mininum, star forming region) in these galaxies. No CO was found at any of the positions observed. We argue that the implied lack of molecular gas is real and not caused by conve

Vivek S. Borkar, Sanjay Jain, Govindan Rangarajan

We discuss a model of an economic community consisting of $N$ interacting agents. The state of each agent at any time is characterized, in general, by a mixed strategy profile drawn from a space of $s$ pure strategies. The community evolves as agents update their strategy profiles in response to payoffs received from other agents. The evolution equation is a

Vivek S. Borkar, Sanjay Jain, Govindan Rangarajan

Many complex adaptive systems contain a large diversity of specialized components. The specialization at the level of the microscopic degrees of freedom, and diversity at the level of the system as a whole are phenomena that appear during the course of evolution of the system. We present a mathematical model to describe these evolutionary phenomena in econom

A. A. Burkov, A. Yu. Zyuzin

The angular and frequency correlation functions of the transmission coefficient for light propagation through a strongly scattering amplifying medium are considered. It is found that just as in the case of an elastic scattering medium the correlation function consists of three terms. However, the structure of the terms is rather different. Angular correlatio

Patrick Cote, Ronald O. Marzke, Michael J. West

The bimodal globular cluster (GC) metallicity distributions of many giant elliptical galaxies are often cited as evidence for the formation of such galaxies through mergers involving gas-rich spirals. In such models, the metal- rich GCs are assumed to have formed during the merger process. We explore an alternative possibility: that these metal-rich clusters

G. Grinstein, Yuhai Tu, J. Tersoff

We analyze the stability of a planar solid-solid interface at which a chemical reaction occurs. Examples include oxidation, nitridation, or silicide formation. Using a continuum model, including a general formula for the stress-dependence of the reaction rate, we show that stress effects can render a planar interface dynamically unstable with respect to pert

Theodore J. Allen, M. G. Olsson, Sinisa Veseli

Recent lattice results for the energy of gluonic excitations as a function of quark separation are shown to correspond to transverse relativistic flux tube vibration modes. For large quark separations all states appear to degenerate into a few categories which are predicted uniquely, given the ground state.

V. Barger, Chung Kao, Tianjun Li

The trilepton signal with missing transverse energy ($3\ell+\notE_T$, with $\ell = e$ or $\mu$) from chargino-neutralino ($\chi^\pm_1 \chi^0_2$) associated production and decays is studied for the upgraded Fermilab Tevatron Collider with 2 TeV center of mass energy and integrated luminosity of 2 fb$^{-1}$ (MI) to 20 fb$^{-1}$ (TeV33). In some regions of para

Kaustubh Agashe

We present a new, improved model of gauge mediation of dynamical SUSY Breaking: the model does not have gauge messengers or $\sim 10$ TeV scalars charged under the Standard Model (SM), thus avoiding the problem of negative (mass)$^2$ for supersymmetric SM (SSM) scalars faced by some earlier models. The gauge mediation is direct, i.e., the messengers which co

Wei Bao, C. Broholm, G. Aeppli, S. A. Carter

Magnetic correlations in all four phases of pure and doped vanadium sesquioxide V_2O_3 have been examined by magnetic thermal neutron scattering. While the antiferromagnetic insulator can be accounted for by a Heisenberg localized spin model, the long range order in the antiferromagnetic metal is an incommensurate spin-density-wave, resulting from a Fermi su

Nelson Padilla, Manuel Merchán, Diego G. Lambas

Our statistical studies comprise the mean relative velocity and velocity correlation for pairs of galaxies as a function of separation, and a bulk flow analysis determined on spheres of $10 h^{-1}$ $Mpc$ radius. In order to test the statistical analysis we use COBE normalized CDM numerical simulations with different density parameters and cosmological consta

A. D. Rutenberg

We determine the evolving segregated or mixed morphology of charged-particle systems with long-range power-law interactions and overall charge neutrality that have been quenched to a low temperature. Segregated morphology systems are characterized by the size of uniformly charged domains, $L(t)$, the particle separation within the domains, $l_{AA}(t)$, the p

D. Cormier

For simple inflationary models, we provide a consistent and complete scheme by which the macro-physical details of early universe inflation may be determined explicitly from the underlying micro-physical theory. We examine inflationary dynamics within the context of a fully renormalized, non-perturbative, and non-equilibrium quantum field theory using the cl

Tim Gebbie, George F. R. Ellis

This is the first of a series of papers extending a covariant and gauge invariant (CGI) treatment of kinetic theory in curved space-times to a treatment of Cosmic Background Radiation (CBR) temperature anisotropies arising from inhomogeneities in the early universe. This paper deals with algebraic issues, both generically and in the context of models lineari

Jintai Ding, Sergei Khoroshkin

We study the possibility to establish $L$-operator's formalism by Faddeev-Reshetikhin-Takhtajan-Semenov-Tian-Shansky (FRST) for quantized current algebras, that is, for quantum affine algebras in the ''new realization '' by V. Drinfeld with the corresponding Hopf algebra structure and for their Yangian counterpart. We establish this formalism using the twist

Jintai Ding, Sergei Khoroshkin

In this paper, we extend the Drinfeld current realization of quantum affine algebras $U_q(\hat {\gg})$ and of the Yangians in several directions: we construct current operators for non-simple roots of ${\gg}$, define a new braid group action in terms of the current operators and describe the universal R-matrix for the corresponding ``Drinfeld'' comultiplicat

N. Ciccoli

Induced representations for quantum groups are defined starting from coisotropic quantum subgroups and their main properties are proved. When the coisotropic quantum subgroup has a suitably defined section such representations can be realized on associated quantum bundles on general embeddable quantum homogeneous spaces.

Oleg Tchernyshyov

Two decades ago, Sadovskii found an exact solution of a model describing a pseudogap in electron energy spectrum (first introduced by Lee, Rice and Anderson). The discovery of a pseudogap in high-Tc superconductors has revived the interest to his exact solution. I review the model with the emphasis on physical content, point out an error in the original Sado

A. A. Andrianov, R. Soldati

A tiny Lorentz symmetry breaking can be mediated in Electrodynamics by means of the Chern-Simons (CS) interaction polarized along a constant CS vector. Its presence makes the vacuum optically active that has been recently estimated from astrophysical data. We examine two possibilities for the CS vector to be time-like or space-like, under the assumption that

A. Ptak, T. Yaqoob, R. Mushotzky, P. Serlemitsos

As a class, LINERs and Low-Luminosity AGN tend to show little or no significant short-term variability (i.e., with time-scales less than a day). This is a marked break for the trend of increased variability in Seyfert 1 galaxies with decreased luminosity. We propose that this difference is due to the lower accretion rate in LINERs and LLAGN which is probably