January 2001 arXiv papers — page 2

N. I. Kochelev, V. Vento

The instanton induced interaction leads to a significant enhancement of the $A_0$ weak amplitude determining the $ΔI=1/2$ rule, through the contribution of operators with dimension d=9, as we show in the weak $K\to ππ$ decay.

Richard J. Szabo

A review of the relationships between matrix models and noncommutative gauge theory is presented. A lattice version of noncommutative Yang-Mills theory is constructed and used to examine some generic properties of noncommutative quantum field theory, such as UV/IR mixing and the appearence of gauge-invariant open Wilson line operators. Morita equivalence in

J. Kortus, I. I. Mazin, K. D. Belashchenko, V. P. Antropov

Boron in MgB_2 forms layers of honeycomb lattices with magnesium as a space filler. Band structure calculations indicate that Mg is substantially ionized, and the bands at the Fermi level derive mainly from B orbitals. Strong bonding with an ionic component and considerable metallic density of states yield a sizeable electron-phonon coupling. Using the rigid

Cosimo Stornaiolo

In this paper we propose a model for the formation of the cosmological voids. We show that cosmological voids can form directly after the collapse of extremely large wavelength perturbations into low-density black holes or cosmological black holes (CBH). Consequently the voids are formed by the comoving expansion of the matter that surrounds the collapsed pe

Mohsen Shadmehri, Jamshid Ghanbari

The self-similar equilibrium models of self-gravitating, rotating, isothermal systems are investigated analytically. In these models the rotation velocity is constant and the density varies as $\frac{f(θ, ϕ)}{r^2}$, where $r$ and $θ$ are the spherical radius and the co-latitude, respectively. The nonaxisymmetric solutions contain three free parameters, one o

M. A. Martin-Delgado, M. Roncaglia, G. Sierra

Using the Boltzmann weights of classical Statistical Mechanics vertex models we define a new class of Tensor Product Ansatzs for 2D quantum lattice systems, characterized by a strong anisotropy, which gives rise to stripe like structures. In the case of the six vertex model we compute exactly, in the thermodynamic limit, the norm of the ansatz and other obse

Ulf Lindstrom, Maxim Zabzine

We study the world-volume effective action of Dp-brane at the tachyonic vacuum which is equivalent to the zero tension limit. Using the Hamiltonian formalism we discuss the algebra of constraints and show that there is a non-trivial ideal of the algebra which corresponds to Virasoro like constraints. The Lagrangian treatment of the model is also considered.

Dominic Joyce

This is the sixth in a series of papers constructing examples of special Lagrangian m-folds in C^m. We present a construction of special Lagrangian cones in C^3 involving two commuting o.d.e.s, motivated by the first two papers of the series. Then we generalize it to a construction of non-conical special Lagrangian 3-folds in C^3 involving three commuting o.

Masud Chaichian, Archil B. Kobakhidze, Mirian Tsulaia

We consider supersymmetric models in 5-dimensional space-time compactified on S**1/Z(2) orbifold where N=2 supersymmetry is explicitly broken down to N=1 by the orbifold projection. We find that the residual N=1 supersymmetry is broken spontaneously by a stable classical wall-like field configurations which can appear even in the simple models discussed. We

Klaus Behrndt

Domain wall solutions have attracted much attention due to their relevance for brane world scenarios and the holographic RG flow. In this talk I discuss the following aspects for these applications: (i) derivation of the first order flow equations as Bogomol'nyi bound; (ii) different types of critical points of the superpotential; (iii) the superpotentia

N. Haba, J. Sato, M. Tanimoto, K. Yoshioka

To search for possible textures of lepton mass matrices, we systematically examine flavor mixing structures which can lead to large lepton mixing angles. We find out 37 mixing patterns are consistent with experimental data, taking into account phase factors in the mixing matrices. Only six of the patterns can explain the observed data without any tuning of p

Yasuaki Hikida, Masatoshi Nozaki, Yuji Sugawara

We study D-branes in SU(2) WZW model by means of the boundary state techniques. We realize the ``fuzzy sphere'' configuration of multiple D0-branes as the boundary state with the insertion of suitable Wilson line. By making use of the path-integral representation we show that this boundary state preserves the appropriate boundary conditions and leads

Thomas M. Tauris, Sushan Konar

We investigate the evolution of pulsars in the (P,P-dot) diagram. We first present analytical formulae to follow the evolution of a pulsar using simple exponential models for magnetic field decay and alignment. We then compare these evolutionary tracks with detailed model calculations using ohmic decay of crustal neutron star magnetic fields. We find that, a

M. Chaichian, A. Demichev, P. Presnajder, M. M. Sheikh-Jabbari

After discussing the peculiarities of quantum systems on noncommutative (NC) spaces with non-trivial topology and the operator representation of the $\star$-product on them, we consider the Aharonov-Bohm and Casimir effects for such spaces. For the case of the Aharonov-Bohm effect, we have obtained an explicit expression for the shift of the phase, which is

Y. Tomio, N. Dupuis, Y. Suzumura

We study spin fluctuations in quarter-filled one-dimensional spin-density-wave systems in presence of short-range Coulomb interactions. By applying a path integral method, the spin-wave velocity is calculated as a function of on-site (U), nearest (V) and next-nearest (V_2) neighbor-site interactions. With increasing V or V_2, the pure spin-density-wave state

R. M. Godbole, D. Indumathi, M. Kraemer

We consider J/psi photoproduction in e+ e- as well as linear photon colliders. We find that the process is dominated by the resolved photon channel. Both the once-resolved and twice-resolved cross-sections are sensitive to (different combinations of) the colour octet matrix elements. Hence, this may be a good testing ground for colour octet contributions in

C. Duval Z. Horváth, P. A. Horváthy

A non-relativistic plasma model endowed with an ``exotic'' structure associated with the two-parameter central extension of the planar Galilei group is constructed. Introducing a Chern-Simons statistical gauge field provides us with a self-consistent system; when the magnetic field takes a critical value determined by the extension parameters, the fl

M. Jezabek, T. Mannel, B. Postler, P. Urban

The hadronic mass distribution in semileptonic B-meson decays can be used for extracting the charmless part and thus determining the |V_ub/V_cb| ratio. We take into account first-order perturbative as well as non-perturbative QCD corrections. The sensitivity to model assumptions is studied and an estimate of the remaining uncertainties is performed.

Shijun Yoshida

We investigate properties of r-modes characterized by regular eigenvalue problem in slowly rotating relativistic polytropes. Our numerical results suggest that discrete r-mode solutions for the regular eigenvalue problem exist only for restricted polytropic models. In particular the r-mode associated with l=m=2, which is considered to be the most important f

M. Pena, G. Stasinska, S. Medina

We present high resolution spectrophotometric data for 34 galactic planetary nebulae with [WC] nuclei (WRPNe).The sample includes PNe with early and late [WC] stars and some WELS. Physical conditions and chemical abundances have been derived and expansion velocities were estimated for most objects of the sample. A statistical study was developed to find fund

César A. Terrero-Escalante, Eloy Ayón-Beato, Alberto A. García

Next-to-leading order expressions related to Stewart-Lyth inverse problem are used to determine the inflationary models with a tensorial power spectrum described by a scale-invariant spectral index. Beyond power-law inflation, solutions are characterized by scale dependent scalar indices. These models can be used as assumption on the generation of primordial

G. Sampath

A quantum computing scheme that uses a single photon and multiple-slit gratings is suggested for the Hamiltonian path problem on a simple graph G of N vertices. The photon is input to an N-slit grating followed by an N x N matrix of `processing units&#39;. A unit consists of a delay line followed by a grating with k slits (0 < k < N) whose outputs are direct

Bernard d&#39;Espagnat

Grounded on the quantum measurement riddle, a general argument against the universal validity of the superposition principle was recently put forward by Bassi and Ghirardi. It is pointed out that this argument is valid only within the realm of the philosophy of ``objectivistic realism&#39;&#39; which is not a necessary part of the foundations of physics, and

Jochen Gemmer, Alexander Otte, Guenter Mahler

We re-interprete the microcanonical conditions in the quantum domain as constraints for the interaction of the &#34;gas-subsystem&#34; under consideration and its environment (&#34;container&#34;). The time-average of a purity-measure is found to equal the average over the respective path in Hilbert-space. We then show that for typical (degenerate or non-deg

D. A. Slavnov

It is proposed the scheme of quantum mechanics, in which a Hilbert space and the linear operators are not primary elements of the theory. Instead of it certain variant of the algebraic approach is considered. The elements of noncommutative algebra (observables) and the nonlinear functionals on this algebra (physical states) are used as the primary constituen

Alexander Otte, Guenter Mahler

Based on local unitary operators acting on a n-dimensional Hilbert-space, we investigate selective and collective operator basis sets for N-particle quantum networks. Selective cluster operators are used to derive the properties of general cat-states for any n and N. Collective operators are conveniently used to account for permutation symmetry: The respecti

O. A. Olkhov

We show that the Dirac equation can be rewritten as a relation describing the fundamental symmetry group of special topological manifold corresponding to the Dirac wave field. It leads to unification of the time-space and internal symmetries within one symmetry group. We suppose that nonelectromagnetic interactions appear within such approach as the deviatio

Julius Ruseckas

We show that it is impossible to determine the time a tunneling particle spends under the barrier. However, it is possible to determine the asymptotic time, i.e., the time the particle spends in a large area including the barrier. We propose a model of time measurements. The model provides a procedure for calculation of the asymptotic tunneling and reflectio

A. V. Turukhin, V. S. Sudarshanam, M. S. Shahriar, J. A. Musser

We report ultraslow group velocities of light in a solid. Light speeds as slow as 45 m/s were observed, corresponding to a group delay of 66 ms in a 3-mm thick crystal. Reduction of the group velocity is accomplished by using a sharp spectral feature in absorption and dispersion, produced by a Raman excited spin coherence in an optically dense Pr doped Y2SiO

V. Carbone, L. Sorriso-Valvo, E. Martines, V. Antoni

We investigate the intermittency of magnetic turbulence as measured in Reversed Field Pinch plasmas. We show that the Probability Distribution Functions of magnetic field differences are not scale invariant, that is the wings of these functions are more important at the smallest scales, a classical signature of intermittency. We show that scaling laws appear

K. V. Klementev

A Bayesian method application to the deconvolution of EXAFS spectra is considered. It is shown that for purposes of EXAFS spectroscopy, from the infinitely large number of Bayesian solutions it is possible to determine an optimal range of solutions, any one from which is appropriate. Since this removes the requirement for the uniqueness of solution, it becom

Michael I. Tribelsky, Sergei I. Anisimov

General phenomenological theory of hydrodynamic waves in regions with smooth loss of convexity of isentropes is developed based on the fact that for most media these regions in p-V plane are anomalously small. Accordingly the waves are usually weak and can be described in the manner analogous to that for weak shock waves of compression. The corresponding gen

Andreas Kabel

With the appropriate choice of parameters and sufficient cooling, charged particles in a circular accelerator are believed to undergo a transition to a highly-ordered crystalline state. The simplest possible crystalline configuration is a one-dimensional chain of particles. In this paper, we write down the quantized version of its dynamics. We show that in a

R. M. Davidson, Ron Workman

We examine the use of phenomenological form factors in tree level amplitudes for meson photoproduction. Two common recipes are shown to be fundamentally incorrect. An alternate form consistent with gauge invariance and crossing symmetry is proposed.

M. Del Estal, M. Centelles, X. Viñas, S. K. Patra

We apply recently developed effective field theory nuclear models in mean field approximation (parameter sets G1 and G2) to describe ground-state properties of nuclei from the valley of $β$-stability up to the drip lines. For faster calculations of open-shell nuclei we employ a modified BCS approach which takes into account quasi-bound levels owing to their

R. Botet, M. Ploszajczak, A. Chbihi, B. Borderie

We discuss the scaling laws of both the charged fragments multiplicity fluctuations and the charge of the largest fragment fluctuations for Xe+Sn collisions in the range of bombarding energies between 25 MeV/A and 50 MeV/A. We show close to E_{lab}=32 MeV/A the transition in the fluctuation regime of the charge of the largest fragment which is compatible wit

Jiri Vanicek, Eric J. Heller

We present a new semiclassical technique which relies on replacing complicated classical manifold structure with simpler manifolds, which are then evaluated by the usual semiclassical rules. Under circumstances where the original manifold structure gives poor or useless results semiclassically the replacement manifolds can yield remarkable accuracy. We give

L. Sorriso-Valvo, V. Carbone, P. Veltri, H. Politano

Intermittency in MHD turbulence has been analyzed using high resolution 2D numerical simulations. We show that the Probability Distribution Functions (PDFs) of the fluctuations of the Elsasser fields, magnetic field and velocity field depend on the scale at hand, that is they are self-affine. The departure of the PDFs from a Gaussian function can be describe

V. Carbone, P. Giuliani, L. Sorriso-Valvo, P. Veltri

Intermittency in fluid turbulence can be evidentiated through the analysis of Probability Distribution Functions (PDF) of velocity fluctuations, which display a strong non-gaussian behavior at small scales. In this paper we investigate the occurrence of intermittency in plasma turbulence by studying the departure from the gaussian distribution of PDF for bot

Ole Bang, Torben Winther Graversen, Joel F. Corney

We consider unseeded Type I second-harmonic generation in quasi-phase-matched (QPM) quadratic nonlinear materials and derive an accurate analytical expression for the evolution of the average intensity. The intensity-dependent nonlinear phase mismatch due to the QPM induced cubic nonlinearity is found. The equivalent formula for the intensity for maximum con

R. M. Kiehn, Phil Baldwin

A system of differential forms will establish a topology and a topological structure on a domain of independent variables such that is possible to determine which maps or processes acting on the system are continuous. Perhaps the most simple topology is that generated by the existence of a single 1-form of Action, its Pfaff sequence of exterior differentials

T. Constantinescu, J. L. Johnson

In this paper we explore the connection between tensor algebras and displacement structure. We describe a scattering experiment in this framework, we obtain a realization of the elements of the tensor algebra as transfer maps of a certain class of nonstationary linear systems, and we describe a Schur algorithm for the Schur elements of the tensor algebra.

Walter D. Neumann, Jonathan Wahl

The quotient-cusp singularities are isolated complex surface singularities that are double-covered by cusp singularities. We show that the universal abelian cover of such a singularity, branched only at the singular point, is a complete intersection cusp singularity of embedding dimension 4. This supports a general conjecture that we make about the universal

David B. Massey

We show that there are obstructions to the existence of certain types of invariant subspaces of the Milnor monodromy; this places restrictions on the cohomology of Milnor fibres of non-isolated hypersurface singularities.

Jean-Marc Schlenker

A classical theorem, mainly due to Aleksandrov and Pogorelov, states that any Riemannian metric on $S^2$ with curvature $K>-1$ is induced on a unique convex surface in $H^3$. A similar result holds with the induced metric replaced by the third fundamental form. We show that the same phenomenon happens with yet another metric on immersed surfaces, which we ca

Greg Lawler, Oded Schramm, Wendelin Werner

This paper gives an accessible (but still technical) self-contained proof to the fact that the intersection probabilities for planar Brownian motion are given in terms of the intersection exponents, up to a bounded multiplicative error, and some closely related results. While most of the results are already known, the proofs are somewhat new, and the paper c

Diego Cordoba, Charles Fefferman

We provide a test for numerical simulations, for several two dimensional incompressible flows, that appear to develop sharp fronts. We show that in order to have a front the velocity has to have uncontrolled velocity growth.

Diego Cordoba, Charles Fefferman

We study the rate of growth of sharp fronts of the Quasi-geostrophic equation and 2D incompressible Euler equations.. The development of sharp fronts are due to a mechanism that piles up level sets very fast. Under a semi-uniform collapse, we obtain a lower bound on the minimum distance between the level sets.

William H. Rowan

Given a variety of algebras V, we study categories of algebras in V with a compatible structure of uniform space. The lattice of compatible uniformities of an algebra, Unif A, can be considered a generalization of the lattice of congruences Con A. Mal&#39;cev properties of V influence the structure of Unif A, much as they do that of Con A. The category V[CHU

S. Majid, T. Schucker

We apply quantum group methods for noncommutative geometry to the $Z_2\times Z_2$ lattice to obtain a natural Dirac operator on this discrete space. This then leads to an interpretation of the Higgs fields as the discrete part of spacetime in the Connes-Lott formalism for elementary particle Lagrangians. The model provides a setting where both the quantum gr

Anderson Ilha, Clovis Wotzasek

We study the effects of interference between the self-dual and anti self-dual massive modes of the linearized Einstein-Chern-Simons topological gravity. The dual models to be used in the interference process are carefully analyzed with special emphasis on their propagating spectrum. We identify the opposite dual aspects, necessary for the application of the

A. Ceresole, G. Dall&#39;Agata

We summarise the present status of supersymmetric Randall-Sundrum brane-world scenarios and report on their possible realisation within five-dimensional matter coupled N=2 gauged supergravity.

Naoki Sasakura

Using the method developed by Callan and Thorlacius, we study the low energy effective geometry on a two-dimensional string lattice by examining the energy-momentum relations of the low energy propagation modes on the lattice. We show that the geometry is identical for both the oscillation modes tangent and transverse to the network plane. We determine the r

R. Rashkov, K. S. Viswanathan, Y. Yang

We study Witten&#39;s background independent open-string field theory in the presence of a constant B-field at one loop level. The Green&#39;s function and the partition function with a constant B-field are evaluated for an annulus.

Bruce A. Campbell, Kirk Kaminsky

Comments on NC Abelian Higgs model withdrawn. An improved treatment of NC U(2) adjoint models to appear elsewhere.

I. V. Tyutin

We study the general form of the noncommutative associative product (the star-product) on the Grassman algebra; the star-product is treated as a deformation of the usual &#34;pointwise&#34; product. We show that up to a similarity transformation, there is only one such product. The relation of the algebra ${\cal F}$, the algebra of elements of the Grassman a

Victor T. Kim, Victor A. Matveev, Grigorii B. Pivovarov, James P. Vary

We explain what is the challenge of light-front quantisation, and how we can now answer it because of recent progress in solving the problem of zero modes in the case of non-Abelian gauge theories. We also give a description of the light-front Hamiltonian for SU(2) finite volume gluodynamics resulting from this recent solution to the problem of light-front z

A. Garcia, R. Huerta, G. Sanchez-Colon

A priori mixings of eigenstates in physical states are quantum mechanical effects well known in several realms of physics. The possibility that such effects are also present in particle physics, in the form of mixings that break flavor and parity symmetries, is studied. Applications to non-leptonic and weak radiative decays of hyperons are discussed. The res

S. Nussinov, R. Shrock

We consider models that generate hierarchies via the separation of fermion wavefunctions in higher-dimensional spaces. We calculate the effects of gauge interactions between fermions and show that these are important and could help to explain (i) why the heaviest known fermion is a charge 2/3 quark, rather than a charge -1/3 quark or a lepton, (ii) why this

M. Burkardt, S. Seal

We present results from a transverse lattice study of low lying mesons. Special emphasis is put on the issue of Lorentz invariant energy-momentum dispersion relations for these mesons. The light-cone wave function for the $π$ obtained in this framework is very close to its asymptotic shape.

Andrzej J. Buras

These lectures give an up to date description of CP violation and rare decays of K and B mesons and consist of ten chapters: i) Grand view of the field including CKM matrix and the unitarity triangle, ii) General aspects of the theoretical framework based on effective weak Hamiltonians, the operator product expansion and the renormalization group, iii) Parti

M. Diehl

We show that for both quarks and gluons there are eight generalized parton distributions in the proton: four which conserve parton helicity and four which do not. We explain why time reversal invariance does not reduce this number from eight to six, as previously assumed in the literature.

Ilya F. Ginzburg, Maria Krawczyk, Per Osland

After operations at the LHC and e^+e^- Linear Colliders it may be found that a Standard-Model-like scenario is realized. In this scenario no new particle will be discovered, except a single Higgs boson having partial widths or coupling constants with fundamental particles, whose squares are close, within anticipated experimental uncertainty, to those of the

C. Q. Geng

We first review the three known chiral anomalies in four dimensions and then use the anomaly free conditions to study the uniqueness of quark and lepton representations and charge quantizations in the standard model. We also extend our results to theory with an arbitrary number of color. Finally, we discuss the family problem.

S. Collins, C. T. H. Davies, J. Hein, R. R. Horgan

We study hadronic two- and three-point correlators relevant for heavy to light pseudoscalar meson semi-leptonic decays, using Symanzik improved glue, D234 light quark and NRQCD heavy quark actions. Detailed comparisons are made between simulations on anisotropic and isotropic lattices involving finite momentum hadrons. We find evidence that having an anisotr

Guy D. Moore, Kari Rummukainen, Anders Tranberg

We present a new method for calculating the bubble nucleation rate in first order phase transitions non-perturbatively on the lattice. The method takes into account all fluctuations and the full dynamical pre-factor. We also present results from applying it to the cubic anisotropy model, which has a radiatively induced, strongly first order phase transition.

P. Cea, L. Cosmai

The vacuum dynamics of SU(2) and SU(3) lattice gauge theories is studied by means of a gauge-invariant effective action defined using the lattice Schrödinger functional at finite temperature. In the case of the SU(3) gauge theory numerical simulations are performed both at zero and finite temperature. The vacuum is probed using an external constant Abelian c

G. Jikia, S. Soldner-Rembold

We present a preliminary study of the production of a light Higgs boson with a mass between 120 and 160 GeV in photon-photon collisions at a Compton collider. The event generator for the backgrounds to a Higgs signal due to bbbar and ccbar heavy quark pair production in polarized Gamma-Gamma collisions is based on a complete next-to-leading order (NLO) pertu

Valentin E. Kuznetsov

In Run II at the Tevatron, the major goal of the upgraded CDF and \dzero detectors is a Higgs search in the mass range of 110-200 GeV. They will also contribute significantly to B physics. Among many possibilities they will be able to measure rare decays of B mesons and improve our knowledge of CP violation in B system through study of B mixing. Various aspe

M. Sharif

We derive matter collineations of the Bianchi types I, II, III, VIII and IX, and Kantowski-Sachs spacetimes. It is found that matter collineations turn out similar to Ricci collineations with different constranit equations. We solve the constraint equation for a particular case and obtain three cosmological models which represent perfect fluid dust solutions

Alexander B. Balakin, Jose&#39; P. S. Lemos

Evolution of electric and magnetic fields in dielectric media, driven by the influence of a strong gravitational wave, is considered for four exactly integrable models. It is shown that the gravitational wave field gives rise to new effects and to singular behaviour in the electromagnetic field.

Paulo G. Macedo

A new 5-dimensional Classical Unified Field Theory of Kaluza-Klein type is formulated using 2 separate scalar fields which are related in such a way as to make the 5-dimensional matter-geometry coupling parameter constant. It is shown that this procedure solves the problem of the variability of the gravity coupling parameter without having to assume a confor

Brien C. Nolan

The behaviour of Jacobi fields along a time-like geodesic running into an isotropic singularity is studied. It is shown that the Jacobi fields are crushed to zero length at a rate which is the same in every direction orthogonal to the geodesic. We show by means of a counter-example that this crushing effect depends crucially on a technicality of the definiti

G. De Risi, M. Gasperini

We compute the spectral distribution of the quantum fluctuations of the vacuum, amplified by inflation, after an arbitrary number of background transitions. Using a graphic representation of the process we find that the final spectrum can be completely determined trough a synthetic set of working rules, and a list of simple algebraic computations.

Ehud B. Segalis, Amos Ori

Recent observations suggest that blobs of matter are ejected with ultra-relativistic speeds in various astrophysical phenomena such as supernova explosions, quasars, and microquasars. In this paper we analyze the gravitational radiation emitted when such an ultra-relativistic blob is ejected from a massive object. We express the gravitational wave by the met

D. H. Santamore, Yuri Levin

We have developed a scheme for reducing LIGO suspension thermal noise close to violin-mode resonances. The idea is to monitor directly the thermally-induced motion of a small portion of (a ``point'' on) each suspension fiber, thereby recording the random forces driving the test-mass motion close to each violin-mode frequency. One can then suppress the therma

Yousuke Itoh, Toshifumi Futamase, Hideki Asada

We study the equation of motion appropriate to an inspiralling binary star system whose constituent stars have strong internal gravity. We use the post-Newtonian approximation with the strong field point particle limit by which we can introduce into general relativity a notion of a point-like particle with strong internal gravity without using Dirac delta di

Wolfram Brenig, Klaus W. Becker, Peter Lemmens

Magnetic properties of a completely frustrated tetrahedral chain are briefly summarized. Using exact diagonalization, and bond-operator theory results for the ground-state phase diagram, the one-triplet excitations and the Raman spectrum are given. The link to novel tellurate materials is clarified.

K. Doll, N. M. Harrison

We study the adsorption of chlorine on the Ag(111) surface with full potential gradient corrected density functional calculations. When considering a root3 x root3 R30degree pattern, we find that the fcc hollow is the most favorable adsorption site. We obtain an Ag-Cl bond length of 2.62 Angstrom which is intermediate between two controversial experimental r

R. A. Serota

We evaluate the distribution function of mesoscopic fluctuations of orbital magnetic response in finite-size level-quantized metal particles and Aharonov-Bohm rings for temperatures smaller than the mean level spacing. We find a broad distribution with the reduced moments much larger than the mean. For strong spin-orbit interaction we find very long tails du

P. Fulde, A. N. Yaresko, A. A. Zvyagin, Y. Grin

An explanation is provided for the heavy quasiparticle excitations in LiV_2O_4. It differs considerably from that of other known heavy-fermion systems. Main ingredients of our theory are the cubic spinel structure of the material and strong short-range correlations of the d electrons. The large gamma-coefficient is shown to result from excitations of Heisenb

Jacek Dziarmaga

A persistent current qubit has two quantum states with opposite currents flowing in a superconducting loop. Their magnetic field couple to nuclear spins. The qubit state is not only perturbed by the spins but it also gets entangled with the spins&#39; state on a very short timescale. However, when the same spins are exposed to a strong but less than critical

Itay Furman, Ofer Biham, Jiang-Kai Zuo, Anna K. Swan

A quantitative comparison between experimental and Monte Carlo simulation results for the epitaxial growth of Cu/Cu(001) in the submonolayer regime is presented. The simulations take into account a complete set of hopping processes whose activation energies are derived from semi-empirical calculations using the embedded-atom method. The island separation is

B. Abdullaev, M. Musakhanov, A. Nakamura

On the base of the diffusion Monte-Carlo method we develop the method allowing to simulate the quantum systems with complex wave function. The method is exact and there are no approximations on the simulations of the module and the phase of the system&#39;s wave function. In our method averaged value of any quantity have no direct contribution from the phase

W. Prellier, Ch. Simon, B. Mercey, M. Hervieu

We have investigated the role of the stress-induced by the presence of the substrate in thin films of colossal magnetoresistive manganites on structural, resistive and magnetic properties. Because of the strong coupling between the small structural distortions related to the charge-ordering (CO) and the resistive properties, the presence of the substrate pre

V. F. Gantmakher, M. V. Golubkov

Resistive superconducting zero-field transition in amorphous In-O films in states from the vicinity of the insulator-superconductor transition is analyzed in terms of two characteristic temperatures: the upper one, $T_{c0}$, where the finite amplitude of the order parameter is established and the lower one, $T_c$, where the phase ordering takes place. It fol

A. V. Rybin, G. G. Varzugin, J. Timonen

A generic mechanism of collapse in the Gross-Pitaevskii equation with attractive interparticle interactions is gained by reformulating this equation as Newton&#39;s equation of motion for a system of particles with a constraint. &#39;Quantum pressure&#39; effects give rise to formation of a potential barrier around the emerging singularity, which prevents a

C. W. J. Beenakker, H. Schomerus, P. G. Silvestrov

The average height of the Coulomb-blockade conductance peaks for chaotic elastic scattering is known to increase by a factor of 4/3 upon breaking time-reversal symmetry. We calculate the temperature dependence of this factor in the regime that the inelastic scattering rate Gamma_in is greater than the mean tunneling rate Gamma_el, which itself is less than t

R. Battiston

The Alpha Magnetic Spectrometer (AMS) is a state of the art detector for the extraterrestrial study of matter, antimatter and missing matter. During the ten days long STS-91 precursor flight in may 1998 AMS collected nearly 100 millions of Cosmic Rays on Low Earth Orbit, measuring with high accuracy their composition. We present results on the flux of proton

D. M. Alexander, F. La Franca, F. Fiore, X. Barcons

We present BeppoSAX observations of the Southern S1 region in the European Large Area ISO Survey (ELAIS). These observations cover an area of ~1.7 sq. deg. and reach an on-axis (~0.7 sq. deg) 2-10 keV (HX) sensitivity of ~10E-13 cgs. This is the first HX analysis of an ISOCAM survey. We detect 9 sources with a signal to noise ratio SNR_HX>3, 4 additional sou

William G. Mathews, David A. Buote, Fabrizio Brighenti

Recent XMM-Newton observations of the cooling flow gas in M87 indicate sharply decreasing oxygen, iron and silicon abundances within $\sim 5$ kpc of the galactic center. This result is unexpected since stellar mass loss and Type Ia supernovae are expected to produce pronounced central abundance maxima for all three elements. However, it has been suggested th

J. S. Alcaniz, J. A. S. Lima

The influence of a dark component on the first epoch of galaxy formation is analysed by using the ages of the three oldest high-redshift galaxies known in the literature. Our results, based on a spatially flat accelerated Universe driven by a &#34;quintessence&#34; component ($p_x = ωρ_x$), show that if the inferred ages of these objects are correct the firs

Ken Pounds, Rick Edelson, Alex Markowitz, Simon Vaughan

Beginning in 1999 January, the bright, strongly variable Narrow-Line Seyfert 1 (NLS1) galaxy Akn 564 has been observed by RXTE once every ~4.3 days. It was also monitored every ~3.2 hr throughout 2000 July. These evenly-sampled observations have allowed the first quantitative comparison of long and short time-scale X-ray variability in an NLS1 and the deriva

Joerg Sanner, Jens Brunzendorf, Jean-Marie Will, Michael Geffert

We present CCD photometry and proper motion studies of the three open star clusters NGC 4103, NGC 5281, and NGC 4755 (kappa Cru). By fitting isochrones to the colour magnitude diagrams, we found that all three objects are young open star clusters with ages of at most t=45 Myr. They are located at distances from approx. 1600 pc to 2200 pc, derived from distan

Shai Kaspi, W. N. Brandt, Hagai Netzer, Ian M. George

(abridged) The high-resolution X-ray spectrum of NGC 3783 shows several dozen absorption lines and a few emission lines from the H-like and He-like ions of O, Ne, Mg, Si, and S as well as from Fe XVII - Fe XXIII L-shell transitions. We have reanalyzed the Chandra HETGS spectrum using better flux and wavelength calibrations along with more robust methods. Com

S. Masi, P. A. R. Ade, J. J Bock, A. Boscaleri

We present mm-wave observations obtained by the BOOMERanG experiment of Galactic emission at intermediate and high (b < -20 deg) Galactic latitudes. We find that this emission is well correlated with extrapolation of the IRAS-DIRBE maps, and is spectrally consistent with thermal emission from interstellar dust (ISD). The ISD brightness in the 410 GHz map has

H. C. Arp, E. M. Burbidge, Y. Chu

Four compact ROSAT X-ray sources very close to the nearby ultraluminous infrared galaxy Arp 220 (IC 4553) have been identified as medium-redshift QSOs. The closest pair lying symmetrically across the galaxy have almost identical redshifts z = 1.25, 1.26. All of the evidence suggests that these QSOs have been ejected from Arp 220 and have large intrinsic reds

M. Cervino, V. Luridiana

When evolutionary synthesis models take into account the stochastic nature of the IMF together with the discrete number of stars in real stellar clusters, typical output turns to dispersion band (where real data can be placed) instead of narrow lines. We present here a qualitative analysis of such dispersion in the SN rate, the kinetic energy and the 14N/12C

Saul Rappaport, Eric Pfahl, Fred Rasio, Philipp Podsiadlowski

We report here on two complementary population synthesis studies which relate directly to the formation and evolution of neutron star binaries in globular clusters. In the first, we compute the probability of retaining neutron stars in globular clusters, and quantitatively confirm the idea that the retention fraction for neutron stars born in binary systems

H. Hirashita, A. Burkert, T. T. Takeuchi

We model the star formation history (SFH) and the chemical evolution of the Galactic disk by combining an infall model and a limit-cycle model of the interstellar medium (ISM). Recent observations have shown that the SFH of the Galactic disk violently variates or oscillates. We model the oscillatory SFH based on the limit-cycle behavior of the fractional mas