June 2002 arXiv papers — page 13

M. Kenmoku, S. Uchida, T. Matsuyama

Topological solutions in the (2+1)-dimensional Einstein theory of gravity are studied within the ADM canonical formalism. It is found that a conical singularity appears in the closed de Sitter universe solution as a topological defect in the case of the Einstein theory with a cosmological constant. Quantum effects on the conical singularity are studied using

L. Sriramkumar

We consider the response of a uniformly accelerated monopole detector that is coupled non-linearly to the nth power of a quantum scalar field in (D+1)-dimensional flat spacetime. We show that, when (D+1) is even, the response of the detector in the Minkowski vacuum is characterized by a Bose-Einstein factor for all n. Whereas, when (D+1) is odd, we find that

Carlos Gershenson

In this paper we expose the theoretical background underlying our current research. This consists in the development of behaviour-based knowledge systems, for closing the gaps between behaviour-based and knowledge-based systems, and also between the understandings of the phenomena they model. We expose the requirements and stages for developing behaviour-bas

William Schuler

This paper extends a polynomial-time parsing algorithm that resolves structural ambiguity in input to a speech-based user interface by calculating and comparing the denotations of rival constituents, given some model of the interfaced application environment (Schuler 2001). The algorithm is extended to incorporate a full set of logical operators, including q

S. Guha, J. D. Rice, Y. T. Yau, C. M. Martin

We present photoluminescence studies as a function of temperature from a series of conjugated polymers and a conjugated molecule with distinctly different backbone conformations. The organic materials investigated here are: planar methylated ladder type poly para-phenylene, semi-planar polyfluorene, and non-planar para hexaphenyl. In the longer-chain polymer

Jeffrey R. Errington, Pablo G. Debenedetti, Salvatore Torquato

We study the size of clusters formed by water molecules possessing large enough tetrahedrality with respect to their nearest neighbors. Using Monte Carlo simulation of the SPC/E model of water, together with a geometric analysis based on Voronoi tessellation, we find that regions of lower density than the bulk are formed by accretion of molecules into cluste

Alexander G. Abanov, Vladimir E. Korepin

We study the probability of formation of ferromagnetic string in the antiferromagnetic spin-1/2 XXZ chain. We show that in the limit of long strings with weak magnetization per site the bosonization technique can be used to address the problem. At zero temperature the obtained probability is Gaussian as a function of the length of the string. At finite but l

Sergio Caracciolo, Andrea Sportiello

We introduce a new model for the generation of random satisfiability problems. It is an extension of the hyper-SAT model of Ricci-Tersenghi, Weigt and Zecchina, which is a variant of the famous K-SAT model: it is extended to q-state variables and relates to a different choice of the statistical ensemble. The model has an exactly solvable statistic: the criti

J. Hlinka, E. Klotins

The elastostatic Green function tensor approach, which was recently used to treat electrostriction in numerical simulation of domain structure formation in cubic ferroelectrics, is reviewed and extended to the crystals of hexagonal and orthorhombic symmetry. The tensorial kernels appearing in the expressions for effective nonlocal interaction of electrostric

T. M. Mishonov, J. O. Indekeu, E. S. Penev

High-temperature superconductors are nowadays found in great variety and hold technological promise. It is still an unsolved mystery that the critical temperature T_c of the basic cuprates is so high. The answer might well be hidden in a conventional corner of theoretical physics, overlooked in the recent hunt for exotic explanations of new effects in these

K. Ivanova, M. Ausloos

How to distinguish and quantify deterministic and random influences on the statistics of turbulence data in meteorology cases is discussed from first principles. Liquid water path (LWP) changes in clouds, as retrieved from radio signals, upon different delay times, can be regarded as a stochastic Markov process. A detrended fluctuation analysis method indica

G. Schmidt, C. Gould, P. Grabs, A. M. Lunde

Semiconductor spintronics will need to control spin injection phenomena in the non-linear regime. In order to study these effects we have performed spin injection measurements from a dilute magnetic semiconductor [(Zn,Be,Mn)Se] into nonmagnetic (Zn,Be)Se at elevated bias. When the applied voltage is increased to a few mV we find a strong decrease of the spin

I. J. Maasilta, Subhasish Chakraborty, I. Kuljanishvili, S. H. Tessmer

We have applied a scanning probe method, Subsurface Charge Accumulation (SCA) imaging, to resolve the local structure of the interior of a semiconductor two-dimensional electron system (2DES) in a tunneling geometry. Near magnetic fields corresponding to integer Landau level filling, submicron scale spatial structure in the out-of-phase component of the tunn

F. Schmüser, B. Schmittmann

A kinetic one-dimensional Ising model is coupled to two heat baths, such that spins at even (odd) lattice sites experience a temperature $T_{e}$ ($% T_{o}$). Spin flips occur with Glauber-type rates generalised to the case of two temperatures. Driven by the temperature differential, the spin chain settles into a non-equilibrium steady state which corresponds

Willy S. Bont

The remarkable preference of biomembranes, to constitute vesicles of certain discrete sizes is explained by using the following properties of phospholipids that are either well understood or at least documented. A. By hexagonal close-packing their fatty acyl chains form a triangular lattice. Their molecules: B. Prefer to form linear arrays that occasionally

A. Zazunov, V. S. Shumeiko, E. N. Bratus', J. Lantz

We investigate the dynamics of a two-level Andreev bound state system in a transmissive quantum point contact embedded in an rf-SQUID. Coherent coupling of the Andreev levels to the circulating supercurrent allows manipulation and read out of the level states. The two-level Hamiltonian for the Andreev levels is derived, and the effect of interaction with the

Audrius Alkauskas, Karsten Flensberg, Ben Yu-Kuang Hu, Antti-Pekka Jauho

We develop a theory for describing frictional drag in bilayer systems with in-plane periodic potential modulations, and use it to investigate the drag between bilayer systems in which one of the layers is modulated in one direction. At low temperatures, as the density of carriers in the modulated layer is changed, we show that the transresistivity component

J. X. Zheng-Johansson, B. Johansson, P-I. Johansson

Based on a first principles treatment of the excitation states we show that superfluidity of superfluid $^4$He (He II) results from a reduction in the number of phonon wavevector $K$ states $\N2(K)$ to a level that is negligibly low when the fluid is confined e.g. in a narrow channel, yet wider than the helium atom correlation length, $Λ$. This is as a resul

A. Capocci, G. Caldarelli, P. De Los Rios

In this letter we present data analysis and modeling of two particular cases of study in the field of growing networks. We analyze WWW data set and authorship collaboration networks in order to check the presence of correlation in the data. The results are reproduced with a pretty good agreement through a suitable modification of the standard AB model of net

Y. S. Gui, C. R. Becker, J. Liu, V. Daumer

The transport properties of a magnetic two dimensional electron gas consisting of a modulation doped n type HgMnTe/HgCdTe quantum well, QW, have been investigated. By analyzing the Shubnikov-de Haas oscillations and the node positions of their beating patterns, we have been able to separate the gate voltage dependent Rashba spin-orbit splitting from the temp

German J. de Valcarcel, Kestutis Staliunas

We show theoretically that broad area lasers driven by a nearly resonant bichromatic field may support dark-ring cavity solitons as well as domain walls and labyrinthine patterns.

J. Links, K. E. Hibberd

We extend a recent construction for an integrable model describing Josephson tunneling between identical BCS systems to the case where the BCS systems have different single particle energy levels. The exact solution of the generalized model is obtained through the Bethe ansatz.

M. J. Bull, B. Fåk, K. A. McEwen, J. A. Mydosh

We have made extensive reciprocal space maps in the heavy-fermion superconductor URu2Si2 using high-resolution time-of-flight single-crystal neutron diffraction to search for signs of a hidden order parameter related to the 17.5 K phase transition. Within the present sensitivity of the experiment (0.007 uB/U-ion for sharp peaks), no additional features such

J. -P. Bouchaud, M. Mezard, M. Potters

We investigate several statistical properties of the order book of three liquid stocks of the Paris Bourse. The results are to a large degree independent of the stock studied. The most interesting features concern (i) the statistics of incoming limit order prices, which follows a power-law around the current price with a diverging mean; and (ii) the humped s

H. -S. Sim, H. Schomerus

We investigate shot noise for quantum dots whose classical phase space consists of both regular and chaotic regions. The noise is systematically suppressed below the universal value of fully chaotic systems, by an amount which varies with the positions of the leads. We analyze the dynamical origin of this effect by a novel way to incorporate diffractive impu

Michael S. Brotherton, Chun Ly, Beverley J. Wills, Sally A. Laurent-Muehleisen

The large, powerful Fanaroff-Riley class II radio source 3CR 68.1 is an optically red quasar with strong evidence for dust reddening, intrinsic ultraviolet line absorption, and X-ray absorption. In the context of its large, extended radio structure and the evidence for intrinsic material along the line of sight, it is a good candidate for a quasar seen throu

M. H. Siegel, S. R. Majewski, I. N. Reid, I. B. Thompson

In an effort to more precisely define the spatial distribution of Galactic field stars, we present an analysis of the photometric parallaxes of 70,000 stars covering nearly 15 square degrees in seven Kapteyn Selected Areas. We address the affects of Malmquist Bias, subgiant/giant contamination, metallicity and binary stars upon the derived density laws. The

M. Terasawa, K. Sumiyoshi, S. Yamada, H. Suzuki

We study the effects of the outer boundary conditions in neutrino-driven winds on the r-process nucleosynthesis. We perform numerical simulations of hydrodynamics of neutrino-driven winds and nuclear reaction network calculations of the r-process. As an outer boundary condition of hydrodynamic calculations, we set a pressure upon the outermost layer of the w

A. Pellerin, A. W. Fullerton, C. Robert, J. C. Howk

An atlas of far-ultraviolet spectra of 45 Galactic OB stars observed with the Far Ultraviolet Spectroscopic Explorer is presented. The atlas covers the wavelength region between 912 and 1185A with an effective spectral resolution of 0.12A. Systematic trends in the morphology and strength of stellar features are discussed. Particular attention is drawn to the

Paul B. Eskridge, Jay A. Frogel, Richard W. Pogge, Alice C. Quillen

We announce the initial release of data from the Ohio State University Bright Spiral Galaxy Survey, a BVRJHK imaging survey of a well-defined sample of 205 bright, nearby spiral galaxies. We present H-band morphological classification on the Hubble sequence for the OSU Survey sample. We compare the H-band classification to B-band classification from our own

Samir Salim, Andrew Gould

We complete construction of a catalog containing improved astrometry and new optical/infrared photometry for the vast majority of NLTT stars lying in the overlap of regions covered by POSS I and by the second incremental 2MASS release, approximately 44% of the sky. The epoch 2000 positions are typically accurate to 130 mas, the proper motions to 5.5 mas/yr,

Robert K. Soberman, Maurice Dubin

The fundamental PP reaction has never been attempted in the laboratory as theory states it cannot be measured within the human life span. This forms the foundation of stellar nucleosynthesis and the standard solar model. Yet numerous observations including the Sun's obvious variability argue the theory is flawed and the reaction occurs in times many orde

L. Arnold, S. Gillet, O. Lardiere, P. Riaud

We report spectroscopic observations (400 to 800nm, R = approx 100) of Earthshine in June, July and October 2001 from which normalised Earth albedo spectra have been derived. The resulting spectra clearly show the blue colour of the Earth due to Rayleigh diffusion in its atmosphere. They also show the signatures of oxygen, ozone and water vapour. We tried to

Stephanie Plante, Marc Sauvage

We analyze the infrared (6-100 micron) spectral energy distribution of the blue compact dwarf and metal-poor (Z=Z_solar/41) galaxy SBS0335-052. With the help of DUSTY (Ivezic et al. 1999), a program that solves the radiation transfer equations in a spherical environment, we evaluate that the infrared (IR) emission of SBS0335-052 is produced by an embedded su

Filippo Fraternali, Massimo Cappi, Renzo Sancisi, Tom Oosterloo

We have detected diffuse soft X-ray emission (0.4-1 keV) from the disk of the spiral galaxy NGC 2403 with Chandra. This diffuse emission (with a total luminosity of 2.1 x 10^38 erg/s and a gas temperature of 2-8 x 10^6 K) is well separated from the numerous bright point sources. NGC 2403 is a luminous spiral galaxy with a high rate of star formation. Recent

Charles L. Curry

Using recent dust continuum data, we generate the intrinsic ellipticity distribution of dense, starless molecular cloud cores. Under the hypothesis that the cores are all either oblate or prolate randomly-oriented spheroids, we show that a satisfactory fit to observations can be obtained with a gaussian prolate distribution having a mean intrinsic axis ratio

T. A. Ensslin

A brief overview on the theory and observations of relativistic particle populations in clusters of galaxies is given. The following topics are addressed: (i) the diffuse relativistic electron population within the intra-cluster medium (ICM) as seen in the cluster wide radio halos and possibly also seen in the high energy X-ray and extreme ultraviolet excess

G. Weigelt, Y. Y. Balega, T. Bloecker, K. -H. Hofmann

We present new near-infrared (JHK) bispectrum speckle-interferometry monitoring of the carbon star IRC+10216 obtained between 1999 and 2001 with the SAO 6m telescope. The J-, H-, and K-band resolutions are 50mas, 56mas, and 73mas, resp. The total sequence of K-band observations covers now 8 epochs from 1995 to 2001 and shows the dynamic evolution of the inne

V. de Heij, R. Braun, W. B. Burton

We combine the catalogs of compact high-velocity HI clouds extracted from the LDS and HIPASS surveys and analyze the all-sky properties of the ensemble. Five principal observables are defined for the CHVC population: (1) the spatial deployment of the objects on the sky, (2) the kinematic distribution, (3) the number distribution of observed HI column densiti

Sergei V. Zharikov, Gaghik H. Tovmassian, Juan Echevarria

Recently, Norton et al. 2002, on the basis of multiwavelength photometry of 1WGA J1958.2+3232, argued that the -1 day alias of the strongest peak in the power spectrum is the true orbital period of the system, casting doubts on the period estimated by Zharikov et al. 2001. We re-analyzed this system using our photometric and spectroscopic data along with the

Ya. N. Istomin, B. V. Komberg

The SN explosion in the closed binary can give the magnetospheric flare possessing the properties of GRB. The SN shock, flowing around the magnetosphere of a magnetized neutron star or a white dwarf, produces a narrow magnetic tail 10^9 cm long, 10^8 cm wide and a magnetic field of 10^6 Gauss. Fast particles (Lorentz factor of 10^4), generated in the tail by

A. Doroshkevich, D. L. Tucker, S. Allam

The Large Scale Structure (LSS) in the galaxy distribution is investigated using the Sloan Digital Sky Survey Early Data Release (SDSS EDR). Using the Minimal Spanning Tree technique we have extracted sets of filaments, of wall-like structures, of galaxy groups, and of rich clusters from this unique sample. The physical properties of these structures were th

A. K. Mittal, D. Lohiya

We present a fractal dust model of the Universe based on Mandelbrot's proposal to replace the standard Cosmological Principle by his Conditional Cosmological Principle within the framework of General Theory of Relativity. This model turns out to be free from the de-Vaucouleurs paradox and is consistent with the SNe1a observations. The expected galaxy cou

P. Romano, S. Mathur, R. W. Pogge, B. M. Peterson

We present a 63 ks FUSE observation of the Narrow-Line Seyfert 1 galaxy Arakelian 564. The spectrum is dominated by the strong emission in the O VI λ\lambda1032, 1038 resonance doublet. Strong, heavily saturated absorption troughs due to Lyman series of Hydrogen, O VI and C III λ977 at velocities near the systemic redshift of Arakelian564 are also observed.

S. A. Studenikin, P. T. Coleridge, N. Ahmed, P. Poole

The magnetoresistance associated with quantum interference corrections in a high mobility, gated InGaAs/InP quantum well structure is studied as a function of temperature, gate voltage, and angle of the tilted magnetic field. Particular attention is paid to the experimental extraction of phase-breaking and spin-orbit scattering times when weak anti- localiza

The MILC Collaboration, C. Bernard, S. Datta, T. DeGrand

We present results for $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios in the presence of two flavors of light sea quarks ($N_f=2$). We use Wilson light valence quarks and Wilson and static heavy valence quarks; the sea quarks are simulated with staggered fermions. Additional quenched simulations with nonperturbatively improved clover fermions allow us t

A. V. Balatsky, Yishay Manassen, Ran Salem

ESR-STM is an emerging technique which is capable of detecting the precession of a single spin. We discuss the mechanism of ESR-STM based on a direct exchange coupling between the tunneling electrons and the local precessing spin S. We claim that since the number of tunneling electrons in a single precessing period is small (~20) one may expect a net tempora

M. Beneke, A. P. Chapovsky, M. Diehl, Th. Feldmann

An important unresolved question in strong interaction physics concerns the parameterization of power-suppressed long-distance effects to hard processes that do not admit an operator product expansion (OPE). Recently Bauer et al.\ have developed an effective field theory framework that allows one to formulate the problem of soft-collinear factorization in te

Dragan Huterer, Martin White

The abundance of clusters at the present epoch and weak gravitational lensing shear both constrain roughly the same combination of the power spectrum normalization sigma_8 and matter energy density Omega_M. The cluster constraint further depends on the normalization of the mass-temperature relation. Therefore, combining the weak lensing and cluster abundance

M. Bernardi, R. K. Sheth, M. Subbarao, G. T. Richards

The effective optical depth in the Ly-alpha forest region of 1061 low-resolution QSO spectra drawn from the SDSS database decreases with decreasing redshift over the range 2.5 < z < 4. Although the evolution is relatively smooth, tau_eff ~ (1+z)^{3.8 pm 0.2}, at z ~ 3.2 the effective optical depth decreases suddenly, by about ten percent with respect to this

Michael Gutperle, Wafic Sabra

Instanton and wormhole solutions are constructed in a d-dimensional gravity theory with an axion-dilaton pair of scalar fields. We discuss the cases of vanishing, positive and negative cosmological constant.

S. Bellucci, E. Ivanov, S. Krivonos

We show that any conformal field theory in d-dimensional Minkowski space, in a phase with spontaneously broken conformal symmetry and with the dilaton among its fields, can be rewritten in terms of the static gauge (d-1)-brane on AdS_(d+1) by means of an invertible change of variables. This nonlinear holographic transformation maps the Minkowski space coordi

Zhong-Hao Mei, Xiang-Qian Luo

Hybrid (exotic) mesons, which are important predictions of quantum chromodynamics (QCD), are states of quarks and anti-quarks bound by excited gluons. First principle lattice study of such states would help us understand the role of ``dynamical&#39;&#39; color in low energy QCD and provide valuable information for experimental search for these new particles.

J. C. Niemeyer, R. Parentani, D. Campo

As a simple model for unknown Planck scale physics, we assume that the quantum modes responsible for producing primordial curvature perturbations during inflation are placed in their instantaneous adiabatic vacuum when their proper momentum reaches a fixed high energy scale M. The resulting power spectrum is derived and presented in a form that exhibits the

Timon Boehm, D. A. Steer

We study the evolution of perturbations on a moving probe D3-brane coupled to a 4-form field in an AdS$_5$-Schwarzschild bulk. The unperturbed dynamics are parametrised by a conserved energy $E$ and lead to Friedmann-Robertson-Walker `mirage&#39; cosmology on the brane with scale factor $a(τ)$. The fluctuations about the unperturbed worldsheet are then descr

P. P. Avelino, C. J. A. P. Martins, C. Santos, E. P. S. Shellard

We study the behaviour of cosmic string networks in contracting universes, and discuss some of their possible consequences. We note that there is a fundamental time asymmetry between defect network evolution for an expanding universe and a contracting universe. A string network with negligible loop production and small-scale structure will asymptotically beh

D. N. Basu

Radioactive decay of nuclei via emission of $α$ particles has been studied theoretically in the framework of a superasymmetric fission model using the double folding (DF) procedure for obtaining the $α$-nucleus interaction potential. The DF nuclear potential has been obtained by folding in the density distribution functions of the $α$ nucleus and the daughte

V. V. Klimov, M. Ducloy

The spontaneous decay rates of an excited atom placed near a dielectric cylinder are investigated. A special attention is paid to the case when the cylinder radius is small in comparison with radiation wavelength (nanofiber or photonic wire). In this case, the analytical expressions of the transition rates for different orientations of dipole are derived. It

David Maurin, Richard Taillet, Fiorenza Donato

In a previous study (Maurin et al., 2001), we explored the set of parameters describing diffusive propagation of cosmic rays (galactic convection, reacceleration, halo thickness, spectral index and normalization of the diffusion coefficient), and we identified those giving a good fit to the measured B/C ratio. This study is now extended to take into account

Pietro Fré, Leonardo Modesto

We introduce a new first order formulation of world-volume actions for p-branes with k-supersymmetry. In this language, which involves more auxiliary fields compensated by more local symmetries, the action is provided by a very compact, simple and elegant formula applicable to any supergravity background. The k-supersymmetry variation against which it is inv

Ezzat G. Bakhoum

A number of well-known difficulties in physics resulted from merging the theory of relativity with the Compton-de Broglie wave mechanics. Two such problems were the failure of Dirac&#39;s relativistic wave equation to predict the correct velocity of the electron, and the fact that the measured yield from nuclear fission was found to be substantially less tha

Florian Meier, Jeremy Levy, Daniel Loss

We study the low energy states of finite spin chains with isotropic (Heisenberg) and anisotropic (XY and Ising-like) exchange interaction with uniform and non-uniform coupling constants. We show that for an odd number of sites a spin cluster qubit can be defined in terms of the ground state doublet. This qubit is remarkably insensitive to the placement and c

M. T. Yamashita, T. Frederico, Lauro Tomio, A. Delfino

The experimental three-atom recombination coefficients of the atomic states $^{23}$Na$|F=1,m_F=-1>$, $^{87}$Rb$|F=1,m_F=-1>$ and $^{85}$Rb$|F=2,m_F=-2>$, together with the corresponding two-body scattering lengths, allow predictions of the trimer bound state energies for such systems in a trap. The recombination parameter is given as a function of the weakly

E. Elizalde, F. C. Santos, A. C. Tort

We investigate the influence of a uniform magnetic field on the zero-point energy of charged fields of two types, namely, a massive charged scalar field under Dirichlet boundary conditions and a massive fermion field under MIT boundary conditions. For the first, exact results are obtained, in terms of exponentially convergent functions, and for the second, t

M. Sasaki, O. C. Martin

Temperature chaos is an extreme sensitivity of the equilibrium state to a change of temperature. It arises in several disordered systems that are described by the so called scaling theory of spin glasses, while it seems to be absent in mean field models. We consider a model spin glass on a tree and show that although it has mean field behavior with replica s

Hiroshi Watabe, Takashi Torii

Spontaneous global symmetry breaking of O(3) scalar field gives rise to point-like topological defects, global monopoles. By taking into account self-gravity,the qualitative feature of the global monopole solutions depends on the vacuum expectation value v of the scalar field. When v < sqrt{1 / 8 pi}, there are global monopole solutions which have a deficit

Jorge Berger

We perform a numeric study of the flux transitions in a superconducting ring at fixed temperature, while the applied field is swept at an ideally slow rate. The current around the ring and its free energy are evaluated. We partially explain some of the known experimental features, and predict a considerably large new feature: in the vicinity of a critical fi

Hiroshi Ohno, Masahiro Takada, Klaus Dolag, Matthias Bartelmann

Intracluster magnetic fields with $ \sim μG $ strength induce Faraday rotation on the cosmic microwave background (CMB) polarization. Measurements of this effect can potentially probe the detailed structure of intracluster magnetic fields across clusters, since the CMB polarization is a continuously varying field on the sky, in contrast to the conventional m

S. Sapmaz, Ya. M. Blanter, L. Gurevich, H. S. J. van der Zant

We theoretically study the interplay between electrical and mechanical properties of suspended, doubly clamped carbon nanotubes in which charging effects dominate. In this geometry, the capacitance between the nanotube and the gate(s) depends on the distance between them. This dependence modifies the usual Coulomb models and we show that it needs to be incor

Christopher Gordon, Neil Turok

The ekpyrotic and cyclic universe scenarios have revived the idea that the density perturbations apparent in today&#39;s universe could have been generated in a `pre-singularity&#39; epoch before the big bang. These scenarios provide explicit mechanisms whereby a scale invariant spectrum of adiabatic perturbations may be generated without the need for cosmic

Johann Rafelski, Jean Letessier

This survey offers an introductory tutorial for students of any age of the currently thriving field of hadrochemistry. We discuss the different chemical potentials, how the hadronic phase space is described and how one evaluates the abundance of hadrons at time of hadronization. We show that a rather accurate description of experimental data arises and we pr

Andrew Das Arulsamy

This paper has been withdrawn because it is published as a single chapter, together with cond-mat/0408613.

Katsuyuki Sugiyama, Kentaroh Yoshida

We study the BPS conditions in the closed supermembranes on the maximally supersymmetric pp-wave background. In particular, the 1/2 and 1/4 BPS states are discussed in detail. Moreover, we comment on the zero-modes in the invariant mass formulae of the theory.

Chuan-Hung Chen

We study the effects of scalar-pseudoscalar mixing induced from quantum loop on $ε&#39;/ε$ in SUSY models with $\tanβ\sim m_{t}/m_{b}$. We find that even the non-universal soft ${\cal A}^{d}$ term and Yukawa matrix, $Y^{d}$, are hermitian, the predicted value of $|ε&#39;/ε|$ can be consistent with the measured results of NA48 and KTeV. And also the EDMs are

H. Kurokawa, T. Fujiwara

It is shown that the eigenvalue problem for the hermitian Wilson-Dirac operator of for a uniform magnetic field in two dimensions can be reduced to one-dimensional problem described by a relativistic analog of the Harper equation. An explicit formula for the secular equations is given in term of a set of polynomials. The spectrum exhibits a fractal structure

Wilhelm I. Fushchych, Anatoly G. Nikitin

There are a number of papers dedicated to the description of free particles and antiparticles with zero mass and spin 1/2. A great many equations with different C, P, T properties have been proposed and the impression could be formed that there are many nonequivalent theories for zero-mass particles. The purpose or this paper is to show that it is not the ca

A. R. Kolovsky, A. V. Ponomarev, H. J. Korsch

The paper studies Bloch oscillations of cold neutral atoms in the optical lattice. The effect of spontaneous emission on the dynamics of the system is analyzed both analytically and numerically. The spontaneous emission is shown to cause (i) the decay of Bloch oscillations with the decrement given by the rate of spontaneous emission and (ii) the diffusive sp

K. Fakhreddine, R. J. Tweed, G. Nguyen Vien, C. Tannous

It is shown how the Canonical Function approach can be used to obtain accurate solutions for the distorted wave problem taking account of direct static and polarisation potentials and exact non-local exchange. Calculations are made for electrons in the field of atomic hydrogen and the phaseshifts are compared with those obtained using a modified form of the

Alexander R. Kessel, Natalia M. Yakovleva

Schemes of experimental realization of the main two qubit processors for quantum computers and Deutsch-Jozsa algorithm are derived in virtual spin representation. The results are applicable for every four quantum states allowing the required properties for quantum processor implementation if for qubit encoding virtual spin representation is used. Four dimens

Wilhelm I. Fushchych

We have shown quant-ph/0206104 (Lett. Nuovo Cimento, 1972, 4, 344) that for free particles and antiparticles with mass m>0 and arbitrary spin s>0, in the framework of the Poincare group P(1,3), there exist three types of nonequivalent equations. In the present paper we study the P, T, C properties of these equations.

Wilhelm I. Fushchych

In previous papers quant-ph/0206077, quant-ph/0206078, quant-ph/0206079 we have shown that there exist three types of the relativistic equations for the massless particles. Here we show that for the free particles and antiparticles with the mass m>0 and the arbitrary spin $s \geq 1/2$ there also exist three types of nonequivalent equations.

U. I. Safronova, W. R. Johnson, M. S. Safronova, J. R. Albritton

Energies of (2s2 2p5 3l3l&#39;) and (2s 2p6 3l3l&#39;) states for sodiumlike ions with Z =14--100 are evaluated to second order in relativistic many-body perturbation theory starting from a neonlike Dirac-Fock potential. Second-order Coulomb and Breit interactions are included. Correction for the frequency-dependence of the Breit interaction is taken into ac

Gad Getz, Hilah Gal, Itai Kela, Eytan Domany

We present and review Coupled Two Way Clustering, a method designed to mine gene expression data. The method identifies submatrices of the total expression matrix, whose clustering analysis reveals partitions of samples (and genes) into biologically relevant classes. We demonstrate, on data from colon and breast cancer, that we are able to identify partition

T. Francke, V. Peskov

This paper describes the present status of the aging studies in various photosensitive detectors. New experimental data are presented on aging of trimethilamine (TMA) and ethilferrocene (EF) photosensitive vapors as well as on CsI and SbCs photocathodes. A new explanation of the CsI photocathodes aging process based on solid state physics theory is given. Fi

V. A. Roudnev

Differential Faddeev equations in total angular momentum representation are used for the first time to investigate ultra-low energy elastic scattering of a helium atom on a helium dimer. Six potential models of interatomic interaction are investigated. The results improve and extend the Faddeev equations based results known in literature. The employed method

J. Rehacek, Z. Hradil, M. Zawisky, W. Treimer

Maximum-likelihood methods are applied to the problem of absorption tomography. The reconstruction is done with the help of an iterative algorithm. We show how the statistics of the illuminating beam can be incorporated into the reconstruction. The proposed reconstruction method can be considered as a useful alternative in the extreme cases where the standar

Eytan Domany

The expression levels of many thousands of genes can be measured simultaneously by DNA microarrays (chips). This novel experimental tool has revolutionized research in molecular biology and generated considerable excitement. A typical experiment uses a few tens of such chips, each dedicated to a single sample - such as tissue extracted from a particular tumo

Jean-Philippe Vert, Minoru Kanehisa

Gene function prediction from microarray data is a first step toward better understanding the machinery of the cell from relatively cheap and easy-to-produce data. In this paper we investigate whether the knowledge of many metabolic pathways and their catalyzing enzymes accumulated over the years can help improve the performance of classifiers for this probl

V. A. Dzuba, O. P. Sushkov, W. R. Johnson, U. I. Safronova

We have calculated energy levels and lifetimes of 4f7 and 4f6 5d configurations of Gd IV using Hartree-Fock and configuration interaction methods. This allows us to reduce significantly the uncertainty of the theoretical determination of the electron electric dipole moment (EDM) enhancement factor in this ion and, correspondingly, in gadolinium-containing ga

Miroslav Sukenik, Jozef Sima

Based on the model of Expansive Nondecelerative Universe, the aim of the present contribution is to contribute to the theoretical rationalization of some experiments, in particular of those performed by Podkletnov and de Aquino and devoted to the gravitational mass cessation, to offer a mechanistic explanation of the Solar corona heating, and to propose an e

A. Bieniek

Medium modifications of the $πωρ$ vertex are analyzed in context of the $ω\to π^0 γ^\ast$ and $ρ\to πγ^\ast$ decays in nuclear matter. A relativistic hadronic model with mesons, nucleons, and $Δ(1232)$ isobars is applied. A substantial increase of the widths for the decays $ω\to π^0 γ^\ast$ and $ρ\to πγ^\ast$ is found for photon virtualities in the range $0.

N. Korabel, R. Klages

A paradigmatic nonhyperbolic dynamical system exhibiting deterministic diffusion is the smooth nonlinear climbing sine map. We find that this map generates fractal hierarchies of normal and anomalous diffusive regions as functions of the control parameter. The measure of these self-similar sets is positive, parameter-dependent, and in case of normal diffusio

Bernard J. Geurts, Darryl D. Holm

A new modeling approach for large-eddy simulation (LES) is obtained by combining a `regularization principle&#39; with an explicit filter and its inversion. This regularization approach allows a systematic derivation of the implied subgrid-model, which resolves the closure problem. The central role of the filter in LES is fully restored, i.e., both the inter

David Damanik, Serguei Tcheremchantsev

We present an approach to quantum dynamical lower bounds for discrete one-dimensional Schrödinger operators which is based on power-law bounds on transfer matrices. It suffices to have such bounds for a nonempty set of energies. We apply this result to various models, including the Fibonacci Hamiltonian.

Alan Horwitz

Let f(x) be a differentiable function on the real line R, and let P be a point not on the graph of f(x). Define the illumination index of P to be the number of distinct tangents to the graph of f which pass thru P. We prove that if f &#39;&#39; is continuous and nonnegative on R, f &#39;&#39; > m >0 outside a closed interval of R, and f &#39;&#39; has finite

Alan Horwitz

Let F and K be fields of characteristic 0, with F a subset of K. Let K[x] denote the ring of polynomials with coefficients in K. For p in K[x]\F[x], deg(p) = n, let r be the highest power of x with a coefficient not in F. We define the F deficit of p to be D_F(p) = n-r. For p in F[x], D_F(p) = n. Suppose that the leading coeffcients of p and q are in F, and

O. Guibert, T. Mansour

In [GM] Guibert and Mansour studied involutions on n letters avoiding (or containing exactly once) 132 and avoiding (or containing exactly once) an arbitrary pattern on k letters. They also established a bijection between 132-avoiding involutions and Dyck word prefixes of same length. Extending this bijection to bilateral words allows to determine more param

Greg Martin

In 1925, Jarnik defined a sequence of convex polygons for use in constructing curves containing many lattice points relative to their curvatures. Properly scaled, these polygons converge to a certain limiting curve. In this paper we identify this limiting curve precisely, showing that it consists piecewise of arcs of parabolas, and we discuss the analogous p

Philippe Biane, Frederick Goodman, Alexandru Nica

We establish connections between the lattices of non-crossing partitions of type B introduced by V. Reiner, and the framework of the free probability theory of D. Voiculescu. Lattices of non-crossing partitions (of type A, up to now) have played an important role in the combinatorics of free probability, primarily via the non-crossing cumulants of R. Speiche

Greg Martin

Many generalizations of continued fractions, where the reciprocal function has been replaced by a more general function, have been studied, and it is often asked whether such generalized expansions can have nice properties. For instance, we might ask that algebraic numbers of a given degree have periodic expansions, just as quadratic irrationals have periodi