May 2003 arXiv papers — page 28

G. Brooijmans

The integrated luminosity at Run 2 of the Tevatron is approaching the Run 1 total, and data analysis is progressing. New results in searches for new physics by the DO experiment are presented in a variety of channels, demonstrating good performance of the detector and detailed understanding of the data.

J. K. Kowalczynski

An exact solution of the Einstein-Maxwell equations enables us to construct a hypothesis on the production of tachyons. The hypothesis determines the kinematical relations for the produced tachyon. It also makes possible to estimate the empiric conditions necessary for the production. These conditions can occur when nonpositive subatomic particles of high en

Sawa Manoff

The notion of null (isotropic) vector field is considered in spaces with affine connections and metrics as models of space or space-time. On its basis the propagation of signals in space-time is considered. The Doppler effect is generalized for these types of spaces. The notions of standard (longitudinal) Doppler effect and transversal Doppler effect are int

G. E. Volovik

The cosmological constant is not an absolute constant. The gravitating part of the vacuum energy is adjusted to the energy density of matter and to other types of the perturbations of the vacuum. We discuss how the vacuum energy responds (i) to the curvature of space in the Einstein closed Universe; (ii) to the expansion rate in the de Sitter Universe; and (

C. Reichhardt, C. J. Olson Reichhardt

We investigate the effects of finite temperature, dc pulse, and ac drives on the charge transport in metallic arrays using numerical simulations. For finite temperatures there is a finite conduction threshold which decreases linearly with temperature. Additionally we find a quadratic scaling of the current-voltage curves which is independent of temperature f

J. Bouchet, R. C. Albers, M. D. Jones, G. Jomard

In this paper we propose a new pseudo-phase crystal structure, based on an orthorhombic distortion of the diamond structure, for the ground-state $α$-phase of plutonium. Electronic-structure calculations in the generalized-gradient approximation give approximately the same total energy for the two structures. Interestingly, our new pseudo-phase structure is

R. van Zon, E. G. D. Cohen

Heat fluctuations are studied in a dissipative system with both mechanical and stochastic components for a simple model: a Brownian particle dragged through water by a moving potential. An extended stationary state fluctuation theorem is derived. For infinite time, this reduces to the conventional fluctuation theorem only for small fluctuations; for large fl

M. M. Abdelhadi, J. A. Jung

This paper reveals the origin of variation in the magnitude and temperature dependence of the normal state resistivity frequently observed in different YBCO single crystal or thin film samples with the same $T_{c}$. We investigated temperature dependence of resistivity in $YBa_{2}Cu_{3}O_{7-δ}$ thin films with 7- $δ= 6.95$ and 6.90, which were subjected to a

Yoshiki Imai, Norio Kawakami, Hirokazu Tsunetsugu

The Hubbard model on the Kagomé lattice is investigated in a metallic phase at half-filling. By introducing anisotropic electron hopping on the lattice, we control geometrical frustration and clarify how the lattice geometry affects physical properties. By means of the fluctuation exchange (FLEX) approximation, we calculate the spin and charge susceptibiliti

D. A. Ivanov, Patrick A. Lee

A normal (non-superconducting) ground state of the t-J model may be variationally approximated by a Gutzwiller-projected wave function. Within this approximation, at small hole doping near half-filling, the normal state favors staggered-flux ordering. Such a staggered-flux state may occur in vortex cores of underdoped high-temperature cuprate superconductors

A. Buzdin, A. Koshelev

We consider the properties of a periodic structure consisting of small alternating 0- and pi- Josephson junctions. We show that depending on the relation between the lengths of the individual junctions, this system can be either in the homogeneous or in the phase-modulated state. The modulated phase appears via a second order phase transition when the mismat

Elihu Abrahams, C. M. Varma

The detailed derivation of a theory for transport in quasi-two-dimensional metals, with small-angle elastic scattering and angle-independent inelastic scattering is presented. The transport equation is solved for a model Fermi surface representing a typical cuprate superconductor. Using the small-angle elastic and the inelastic scattering rates deduced from

T. P. Devereaux, G. E. D. McCormack, J. K. Freericks

We construct an exact dynamical mean field theory for nonresonant inelastic light scattering in the infinite-dimensional Falicov-Kimball model, which can be tuned through a quantum critical metal-insulator transition. Due to the projection of the polarization orientations onto different regions of the Brillouin zone and due to the transfer of energy and mome

V. Turkowski, V. R. Vieira, P. D. Sacramento

The time-dependent behavior of the Heisenberg model in contact with a phonon heat bath and in an external time-dependent magnetic field is studied by means of a path integral approach. The action of the phonon heat bath is taken into account up to the second order in the coupling to the heath bath. It is shown that there is a minimal value of the magnetic fi

A. Rakos, M. Paessens, G. M. Schuetz

We introduce a simple nonequilibrium model for a driven diffusive system with nonconservative reaction kinetics which exhibits ergodicity breaking and hysteresis in one dimension. These phenomena can be understood through a description of the dominant stochastic many-body dynamics in terms of an equilibrium single-particle problem, viz. the random motion of

I. Galanakis

I report systematic first-principle calculations of the quaternary Heusler alloys like Co$_2$[Cr$_{1-x}$Mn$_x$]Al, Co$_2$Mn[Al$_{1-x}$Sn$_x$] and [Fe$_{1-x}$Co$_x$]$_2$MnAl. I show that when the two limiting cases (x=0 or 1) correspond to a half-metallic compound, so do the intermediate cases. Moreover the total spin moment $M_t$ in $μ_B$ scales linearly wit

Zoran Konkoli

Theoretical methods for dealing with diffusion-controlled reactions inevitably rely on some kind of approximation and to find the one that works on a particular problem is not always easy. In here the approximation used by Bogolyubov to study weakly non-ideal Bose gas, to be refereed to as weakly non-ideal Bose gas approximation (WBGA), is applied in the ana

H. W. Diehl, M. Shpot

We show that the recent renormalization-group analysis of Lifshitz critical behavior presented by Leite [Phys. Rev. B {\bf 67}, 104415 (2003)] suffers from a number of severe deficiencies. In particular, we show that his approach does not give an ultraviolet finite renormalized theory, is plagued by inconsistencies, misses the existence of a nontrivial aniso

L. S. Metlov

The kinetics of dislocations is studied with computer simulation at loadings of different intensity. It is established that the dislocations have a few different structural states. The dislocations "with the micropore" play important role in the formation of large curved boundaries, and, as a consequence, in the formation of fine grains. Alternation

Antonio Siber

I demonstrate that $^4$He adsorbates in carbon nanotube materials can be treated as one-dimensional interacting gas of spinless bosons for temperatures below 8 K and for coverages such that all the adsorbates are in the groove positions of the carbon nanotube bundles. The effects of adsorbate-adsorbate interactions are studied within the scheme of virial exp

S. Dorbolo, N. Vandewalle

We present experimental investigations of antibubbles. Such an unusual fluid object is a thin spherical air shell surrounding a liquid globule. We explain how to produce them and we study their stability. By overweighting antibubbles with a small amount of salt, they sink and pop at a definite depth. A critical depth related to a critical pressure has been f

Johannes Bonnekoh

The Ising model shows on growing Barabasi - Albert networks the same ferromagnetic behavior as on static Barabasi - Albert networks. Sznajd models on growing Barabasi - Albert networks show an hysteresis like behavior. Nearly a full consensus builds up and the winning opinion depends on history. On slow growing Barabasi - Albert networks a full consensus bui

A. Slobodskyy, C. Gould, T. Slobodskyy, C. R. Becker

We have fabricated all II-VI semiconductor resonant tunneling diodes based on the (Zn,Mn,Be)Se material system, containing dilute magnetic material in the quantum well, and studied their current-voltage characteristics. When subjected to an external magnetic field the resulting spin splitting of the levels in the quantum well leads to a splitting of the tran

T. Takagi, V. Khovailo, T. Nagatomo, M. Matsumoto

Mechanical and shape memory properties of a polycrystalline Ni2.18Mn0.82Ga alloy prepared by a PDS (Pulse Discharge Sintering) method were investigated. It was found that the material demonstrates the two-way shape memory effect after a loading - unloading cycle performed in the martensitic state, i. e. essentially without special training. The samples exhib

R. O. Sokolovskii, M. E. Cates, T. G. Sokolovska

We consider a lattice gas with quenched impurities or `quenched-annealed binary mixture' on the Bethe lattice. The quenched part represents a porous matrix in which the (annealed) lattice gas resides. This model features the 3 main factors of fluids in random porous media: wetting, randomness and confinement. The recursive character of the Bethe lattice

Claudio Chamon, Masaki Oshikawa, Ian Affleck

We study a junction of three quantum wires enclosing a magnetic flux. This is the simplest problem of a quantum junction between Tomonaga-Luttinger liquids in which Fermi statistics enter in a non-trivial way. We present a direct connection between this problem and the dissipative Hofstadter problem, or quantum Brownian motion in two dimensions in a periodic

T. Senthil, Subir Sachdev, Matthias Vojta

In spatial dimensions d >= 2, Kondo lattice models of conduction and local moment electrons can exhibit a fractionalized, non-magnetic state (FL*) with a Fermi surface of sharp electron-like quasiparticles, enclosing a volume quantized by (ρ_a-1)(mod 2), with ρ_a the mean number of all electrons per unit cell of the ground state. Such states have fractionali

Ramotholo R. Sefako, Ocker C. de Jager

We present a new model for the synchrotron compact nebular emissions for Vela and PSR B1706-44, and derive fundamental pulsar/plerion parameters such as the pair production multiplicity, M, and wind magnetization parameter, sigma. The pair cascade above the pulsar polar cap, combined with the energy from the pulsar wind, injects a pair plasma into the surrou

Menas Kafatos, Sisir Roy, Malabika Roy

Theories of fundamental physics as well as cosmology must ultimately not only account for the structure and evolution of the universe and the physics of fundamental interactions, but also lead to an understanding of why this particular universe follows the physics that it does. Such theories must ultimately lead to an understanding of the values of the funda

F. Bertoldi, C. L. Carilli, P. Cox, X. Fan

We report observations of three SDSS z>6 QSOs at 250 GHz (1.2mm) using the 117-channel Max-Planck Millimeter Bolometer (MAMBO-2) array at the IRAM 30-meter telescope. J1148+5251 (z=6.41) and J1048+4637 (z=6.23) were detected with 250 GHz flux densities of 5.0 +- 0.6 mJy and 3.0 +- 0.4 mJy, respectively. J1630+4012 (z=6.05) was not detected with a 3 sigma upp

F. X. Timmes, Edward F. Brown, J. W. Truran

We explore the idea that the observed variations in the peak luminosities of Type Ia supernovae originate in part from a scatter in metallicity of the main-sequence stars that become white dwarfs. Previous, numerical, studies have not self-consistently explored metallicities greater than solar. One-dimensional Chandrasekhar mass models of SNe Ia produce most

M. B. Bell, S. P. Comeau

Evidence was presented recently suggesting that the Fundamental Plane (FP) clusters studied in the Hubble Key Project may contain quantized intrinsic redshift components that are related to those reported by Tifft. Here we report the results of a similar analysis using 55 spiral (Sc and Sb) galaxies, and 36 Type Ia supernovae (SnIa) galaxies. We find that ev

A. Sozzetti, S. Casertano, M. G. Lattanzi, A. Spagna

We evaluate the potential of the ESA Cornerstone Mission GAIA in helping populate the database of nearby stars ($d < 25$ pc) for subsequent target selection for DARWIN/TPF. The GAIA high-precision astrometric measurements will make it an ideal tool for a complete screening of the expected several thousands stars within 25 pc in order to identify and characte

John Dubinski, Robin Humble, Ue-Li Pen, Chris Loken

We describe a new 512-CPU Beowulf cluster with Teraflop performance dedicated to problems in computational astrophysics. The cluster incorporates a cubic network topology based on inexpensive commodity 24-port gigabit switches and point to point connections through the second gigabit port on each Linux server. This configuration has network performance compe

B. Lefloch, J. Cernicharo, S. Cabrit, A. Noriega-Crespo

We report on spectro-imaging observations of the Herbig-Haro 2 outflow with the ISOCAM camera onboard the Infrared Space Observatory (ISO). The [Ne II}] 12.81 microns and [Ne III]15.55 microns lines are detected only towards the jet working surface (HH 2H), consistent with the high excitation of this knot in the optical range, while H2 pure rotational emissi

L. Monaco, F. R. Ferraro, M. Bellazzini, E. Pancino

The Sagittarius dwarf spheroidal (Sgr) and a few paculiar Galactic Globular Clusters (GGC) can be considered as building blocks of theGalactic Halo. We present a series of results based on a wide field photometry of the Sgr system and the GGC M22. In particular for Sgr we present: (1) the detection of the RGB-bump, a feature that together with the shape of t

A. Rau, J. Greiner, M. L. McCollough

We report on the discovery of a 590 days long term periodicity in the hard X-ray component of the microquasar \grs found from a comprehensive study of more than four years of {\it RXTE} observations. The periodicity is also observed in the hard X-ray flux observed by BATSE, and in the radio flux as seen with the {\it Green Bank Interferometer} and the {\it R

L. Magrini, R. L. M. Corradi, R. Greimel, P. Leisy

In the framework of our narrow-band survey of the Local Group galaxies, we present the results of the search for planetary nebulae (PNe) in the dwarf irregular galaxies IC10, LeoA and SextansA. Using the standard on-band/off-band technique, sixteen new candidate PNe have been discovered in the closest starburst galaxy, IC10. The optical size of this galaxy i

Christian R. Kaiser

The X-ray data obtained with XMM-Newton is used to investigate the complex structure of the gas in the atmosphere of the Virgo cluster around M87. We construct a simple model for the temperature and density distribution. This model implies that the cumulative mass of the cluster gas is a power-law of its entropy index, $kT n^{-2/3}$, similar to the Hydra clu

K. J. van der Heyden, J. A. M. Bleeker, J. S. Kaastra, J. Vink

The X-ray emission from the supernova remnant DEM L 71 is measured and analysed using the high-resolution cameras and spectrometers on board XMM-Newton. The spectrum from the outer shell is reproduced very well by two plasma components of kT = 0.3 and 0.8 keV. The abundance value from this shell is consistent with the average LMC values. More extreme tempera

Giuseppe Bono

The RR Lyrae distance scale is reviewed. In particular, we discuss theoretical and empirical methods currently adopted in the literature. Moreover, we also outline pros and cons of optical and near-infrared mean magnitudes to overcome some of the problems currently affecting RR Lyrae distances. The importance of the K-band Period-Luminosity-Metallicity (PLZ_

J. Reunanen, J. Kotilainen, M. A. Prieto

We present sub-arcsec near-infrared 1.5 - 2.5 micron moderate resolution long-slit spectra of eight nearby Seyfert galaxies (z<0.01), both parallel to the ionization cone and perpendicular to it. These spectra complement similar data on six Seyferts, presented in Reunanen, Kotilainen & Prieto (2002). Large concentrations of molecular gas (H2) are present in

Glenn J. White, Stephen B. G. Serjeant

The VLTI/GENIE configuration will operate using at least 4 of the VLTI telescopes (and possibly with one or more of the AT telescopes in the future if adaptive optics become available on them). GENIE effectively can be thought of as a &#39;smart&#39; coronagraph, enabling high dynamic range imaging to be achieved at moderate spatial resolution, with high rej

Paul S. Smith, Gary D. Schmidt, Dean C. Hines, Craig B. Foltz

Highly polarized QSOs discovered in the Two-Micron All Sky Survey (2MASS) have been observed to determine the source(s) of optical polarization in this near-infrared color-selected sample. Broad emission lines are observed in the polarized flux spectra of most objects, and the polarization of the lines is at about the same level and position angle as the con

M. R. Nolta, E. L. Wright, L. Page, C. L. Bennett

The first-year WMAP data, in combination with any one of a number of other cosmic probes, show that we live in a flat Λ-dominated CDM universe with Ω_m ~ 0.27 and Ω_Λ~ 0.73. In this model the late-time action of the dark energy, through the integrated Sachs-Wolfe effect, should produce CMB anisotropies correlated with matter density fluctuations at z<2 (Crit

Bian Weihao, Zhao Yongheng

We used the standard geometrical thin accretion theory to obtain the accretion rates in Seyfert 1 galaxies and quasars. Combining accretion rates with the bolometric luminosity, we obtained the accretion efficiency. We found most of Seyfert 1 galaxies and radio quiet quasars have lower accretion efficiencies while most of the radio loud quasars possess highe

Bian Weihao, Zhao Yongheng

It has been thought that narrow-line Seyfert 1 galaxies are likely to be in the early stages of the evolution of active galaxies. To test this suggestion, the ratios of the central massive black hole (MBH) mass to the bulge mass ($M_{\rm bh}/M_{\rm bulge}$) were estimated for 22 Narrow Line AGNs (NL AGNs). It is found that NL AGNs appear to have genuinely lo

A. E. Hornschemeier, F. E. Bauer, D. M. Alexander, W. N. Brandt

We have analyzed optically bright, X-ray faint [OBXF; i.e., log(fX/fR) < -2] sources identified in an 178.9 square arcminute area within the Chandra Deep Field-North (CDF-N) 2 Ms survey. We find 43 OBXF sources in this area, comprising ~15% of the X-ray sources above a 0.5--2 keV flux of 2.3e-17 erg cm^-2 s^-1. We present spectroscopic identifications for 42

Mark A. Scheel, Adrienne L. Erickcek, Lior M. Burko, Lawrence E. Kidder

We investigate the behavior of a dynamical scalar field on a fixed Kerr background in Kerr-Schild coordinates using a 3+1 dimensional spectral evolution code, and we measure the power-law tail decay that occurs at late times. We compare evolutions of initial data proportional to f(r) Y_lm(theta,phi) where Y_lm is a spherical harmonic and (r,theta,phi) are Ke

S. Ludwig, D. D. Osheroff

In non-equilibrium experiments on the glasses Mylar and BK7, we measured the excess dielectric response after the temporary application of a strong electric bias field at mK--temperatures. A model recently developed describes the observed long time decays qualitatively for Mylar [PRL 90, 105501, S. Ludwig, P. Nalbach, D. Rosenberg, D. Osheroff], but fails fo

William M. Goldman

The group Gamma of automorphisms of the polynomial kappa(x,y,z) = x^2 + y^2 + z^2 - xyz -2 is isomorphic to PGL(2,Z) semi-direct product with (Z/2+Z/2). For t in R, Gamma-action on ktR = kappa^{-1}(t) intersect R displays rich and varied dynamics. The action of Gamma preserves a Poisson structure defining a Gamma-invariant area form on each ktR. For t < 2, t

Alex G. Dias, M. Gomes, A. J. da Silva

We study the vacuum stability of a model of massless scalar and fermionic fields minimally coupled to a Chern-Simons field. The classical Lagrangian only involves dimensionless parameters, and the model can be thought as a (2+1) dimensional analog of the Coleman-Weinberg model. By calculating the effective potential, we show that dynamical symmetry breakdown

Ian A. Bonnell, Matthew R. Bate, Stephen G. Vine

Recent surveys of star forming regions have shown that most stars, and probably all massive stars, are born in dense stellar clusters. The mechanism by which a molecular cloud fragments to form several hundred to thousands of individual stars has remained elusive. Here, we use a numerical simulation to follow the fragmentation of a turbulent molecular cloud

B. F. L. Ward

We use exact results in a new approach to quantum gravity to study the effect of quantum loop corrections on the behavior of the metric of space-time near the Schwarzschild radius of a massive point particle in the Standard Model. We show that the classical conclusion that such a system is a black hole is obviated. Phenomenological implications are discussed

Carl L. Gardner

Cosmological variation of the fine structure constant $α$ due to the evolution of a spatially homogeneous ultra-light scalar field ($m \sim H_0$) during the matter and $Λ$ dominated eras is analyzed. Agreement of $Δα/α$ with the value suggested by recent observations of quasar absorption lines is obtained by adjusting a single parameter, the coupling of the

Hidenori Fukaya, Tetsuya Onogi

Lüscher&#39;s ``admissibility&#39;&#39; condition on the gauge field space plays an essential role in constructing lattice gauge theories which has exact chiral symmetries. We apply the gauge action proposed by Lüscher with the domain-wall fermion action to the numerical simulation of the massive Schwinger model. We find this action can generate configuratio

Robert de Mello Koch, Aristomenis Donos, Antal Jevicki, Joao P. Rodrigues

We continue the development of a systematic procedure for deriving closed string pp wave string field theory from the large N Berenstein-Maldacena-Nastase limit. In the present paper the effects of the Yang-Mills interaction are considered in detail for general BMN states. The SFT interaction with the appropriate operator insertion at the interaction point i

Hume A. Feldman, Roman Juszkiewicz, Pedro Ferreira, Marc Davis

Using mean relative peculiar velocity measurements for pairs of galaxies, we estimate the cosmological density parameter $Ω_m$ and the amplitude of density fluctuations $σ_8$. Our results suggest that our statistic is a robust and reproducible measure of the mean pairwise velocity and thereby the $Ω_m$ parameter. We get $Ω_m = 0.30^{+0.17}_{-0.07}$ and $σ_8

Alessandro Cesarini, Francesco Fucito, Andrea Lionetto, Aldo Morselli

The EGRET telescope has identified a gamma-ray source at the Galactic center. We point out here that the spectral features of this source are compatible with the gamma-ray flux induced by pair annihilations of dark matter weakly interacting massive particles (WIMPs). We show that the discrimination between this interpretation and other viable explanations wi

Y. Yaish, J. -Y. Park, S. Rosenblatt, V. Sazonova

We use an Atomic Force Microscope (AFM) tip to locally probe the electronic properties of semiconducting carbon nanotube transistors. A gold-coated AFM tip serves as a voltage or current probe in three-probe measurement setup. Using the tip as a movable current probe, we investigate the scaling of the device properties with channel length. Using the tip as a

Mahn-Soo Choi, David Sanchez, Rosa Lopez

We investigate the effects of spin-polarized leads on the Kondo physics of a quantum dot using the numerical renormalization group method. Our study demonstrates in an unambiguous way that the Kondo effect is not necessarily suppressed by the lead polarization: While the Kondo effect is quenched for the asymmetric Anderson model, it survives even for finite

Andris Ambainis

The degree of a polynomial representing (or approximating) a function f is a lower bound for the number of quantum queries needed to compute f. This observation has been a source of many lower bounds on quantum algorithms. It has been an open problem whether this lower bound is tight. We exhibit a function with polynomial degree M and quantum query complexit

Igor O. Cherednikov

The analysis of nonperturbative effects in high energy asymptotics of the electomagnetic quark form factor is presented. It is shown that the nonperturbative effects determine the initial value for the perturbative evolution of the quark form factor and find their general structure with respect to the high energy asymptotics. Within the Wilson integral forma

S. R. Gevorkyan, I. P. Ivanov, N. N. Nikolaev

We point out a significance of ultraperipheral photoproduction of vector mesons in the Coulomb field of nuclei as a means of measuring the radius of the neutral vector meson. This new contribution to the production amplitude is very small compared to the conventional diffractive amplitude, but because of large impact parameters inherent to the ultraperiphera

Kavita Jain, Mustansir Barma

We study a driven zero range process which models a closed system of attractive particles that hop with site-dependent rates and whose steady state shows a condensation transition with increasing density. We characterise the dynamical properties of the mass fluctuations in the steady state in one dimension both analytically and numerically and show that the

G. I. Gomero

Suppose we have identified three clusters of galaxies as being topological copies of the same object. How does this information constrain the possible models for the shape of our Universe? It is shown here that, if the Universe has flat spatial sections, these multiple images can be accommodated within any of the six classes of compact orientable 3-dimension

T. Hyodo, S. I. Nam, D. Jido, A. Hosaka

We study s-wave meson-baryon scattering using the chiral unitary model. We consider $1/2^{-}$ baryon resonances as quasibound states of the low lying mesons ($π,K,η$) and baryons ($N,Λ,Σ,Ξ$). In previous works, the subtraction constants which appear in loop integrals were found to largely depend on the channels, and it was necessary to fit these constants to

Eric G. Blackman

It is shown that in magnetohydrodynamics, the shapes of the magnetic energy and magnetic helicity spectra can influence whether the magnetic helicity resistive dissipation time scale is longer, equal to, or shorter than that of magnetic energy. The calculations highlight that magnetic helicity need not always dissipate significantly more slowly than magnetic

Shin&#39;ichiro Ando, Katsuhiko Sato

We study the resonant spin-flavor (RSF) conversion of supernova neutrinos, which is induced by the interaction between the nonzero neutrino magnetic moment and the supernova magnetic fields, and its dependence on presupernova models. As the presupernova models, we adopt the latest ones by Woosley, Heger, and Weaver, and, further, models with both solar and z

P. Narayana Swamy

The intimate connection between q-deformed Heisenberg uncertainty relation and the Jackson derivative based on q-basic numbers has been noted in the literature. The purpose of this work is to establish this connection in a clear and self-consistent formulation and to show explicitly how the Jackson derivative arises naturally. We utilize a holomorphic repres

Stefan Heinrich

A basic problem of approximation theory, the approximation of functions from the Sobolev space W_p^r([0,1]^d) in the norm of L_q([0,1]^d), is considered from the point of view of quantum computation. We determine the quantum query complexity of this problem (up to logarithmic factors). It turns out that in certain regions of the domain of parameters p,q,r,d

Stefan Heinrich

We study approximation of embeddings between finite dimensional L_p spaces in the quantum model of computation. For the quantum query complexity of this problem matching (up to logarithmic factors) upper and lower bounds are obtained. The results show that for certain regions of the parameter domain quantum computation can essentially improve the rate of con

M. L. Dalla Chiara, R. Giuntini, R. Leporini

Quantum computation has suggested new forms of quantum logic, called quantum computational logics. The basic semantic idea is the following: the meaning of a sentence is identified with a quregister, a system of qubits, representing a possible pure state of a compound quantum system. The generalization to mixed states, which might be useful to analyse entang

Levon Mardoyan, Armen Nersessian, Mara Petrosyan

The linear Stark effect in the MIC-Kepler problem describing the interaction of charged particle with Dirac&#39;s dyon is considered. It is shown that constant homogeneous electric field completely removes the degeneracy of the energy levels on azimuth quantum number

Arul Lakshminarayan

We use simple deterministic dynamical systems as coins in studying quantum walks. These dynamical systems can be chosen to display, in the classical limit, a range of behaviors from the integrable to chaotic, or deterministically random. As an example of an integrable coin we study the Fourier walk that generalizes the Hadamard walk and show that the walker

E. B. Alexandrov, V. S. Zapasskii

It is shown that the interpretation of the experimental results reported in the publication Storage of Light in Atomic Vapor&#34; by D.F.Phillips et al., Phys. Rev.Lett. 86, 783 (2001) is incorrect. The experimental observation of this paper can be consistently explained in the framework of standard concepts of the physics of optical pumping and have nothing

Subhash Kak

The notion of quantum information related to the two different perspectives of the global and local states is examined. There is circularity in the definition of quantum information because we can speak only of the information of systems that have been specifically prepared. In particular, we examine the final state obtained by applying unitary transformatio

Bernhard Kaufmann

A finite sum of exponential functions may be expressed by a linear combination of powers of the independent variable and by successive integrals of the sum. This is proved for the general case and the connection between the parameters in the sum and the coefficients in the linear combination is highlighted. The fitting of exponential functions to a given dat

N. Armstrong, W. Kalceff, J. P. Cline, J. Bonevich

A single and self-contained method for determining the crystallite-size distribution and shape from experimental x-ray line profile data is presented. We have shown that the crystallite-size distribution can be determined without assuming a functional form for the size distribution, determining instead the size distribution with the least assumptions by appl

Nicolas Delerue

Ground motion at the Future JLC detector may affect beam alignment and cause huge luminosity loss. The FEATHER (FEedback AT High Energy Requirements) project addresses this problem by designing a fast intra-pulse feedback system that will correct the observed beam offset.

Li Yao, Ke-Li Han, He-Shan Song, Dong-Hui Zhang

Time-dependent wave packet calculations for the reaction H+HCl and its isotopic reactions are carried out on the potential energy surface (PES) of Bian and Werner (BW2) [Bian, W.; Werner, H. -J., J. Chem. Phys. 2000, 112, 220]. Reaction probabilities for the exchanged and abstraction channels are calculated from various initial rotational states of the reage

Joseph N. Ginocchio, A. Leviatan

We consider properties of critical points in the interacting boson model, corresponding to flat-bottomed potentials as encountered in a second-order phase transition between spherical and deformed $γ$-unstable nuclei. We show that intrinsic states with an effective $β$-deformation reproduce the dynamics of the underlying non-rigid shapes. The effective defor

A. Leviatan

We introduce the notion of a partial dynamical symmetry for which a prescribed symmetry is neither exact nor completely broken. We survey the different types of partial dynamical symmetries and present empirical examples in each category.

CERES Collaboration

Measurements of event-by-event fluctuations of the mean transverse momentum in Pb-Au collisions at 40, 80, and 158 A GeV/c are presented. A significant excess of mean p_T fluctuations at mid-rapidity is observed over the expectation from statistically independent particle emission. The results are somewhat smaller than recent measurements at RHIC. A possible

Jean-Pierre Eckmann, Emmanuel Zabey

We study the heat transport in systems of coupled oscillators driven out of equilibrium by Gaussian heat baths. We illustrate with a few examples that such systems can exhibit ``strange&#39;&#39; transport phenomena. In particular, {\em circulation} of heat flux may appear in the steady state of a system of three oscillators only. This indicates that the dir

Jedrzej Sniatycki

We discuss smooth nonlinear control systems with symmetry. For a free and proper action of the symmetry group, the reduction of symmetry gives rise to a reduced smooth nonlinear control system. If the action of the symmetry group is only proper, the reduced nonlinear control system need not be smooth. Using the smooth calculus on nonsmooth spaces, provided b

Marco Cannone, Grzegorz Karch

The first goal of this paper is to study the large time behavior of solutions to the Cauchy problem for the 3-dimensional incompressible Navier-Stokes system. The Marcinkiewicz space $L^{3,\infty}$ is used to prove some asymptotic stability results for solutions with infinite energy. Next, this approach is applied to the analysis of two classical ``regulariz

Anton Malkin, Viktor Ostrik, Maxim Vybornov

The minimal degeneration singularities in the affine Grassmannians of simple simply-laced algebraic groups are determined to be either Kleinian singularities of type A, or closures of minimal orbits in nilpotent cones. The singularities for non-simply-laced types are studied by intersection cohomology and equivariant Chow group methods.

Carel Faber, Gerard van der Geer

We consider the cohomology of local systems on the moduli space of curves of genus 2 and the moduli space of abelian surfaces. We give an explicit formula for the Eisenstein cohomology and a conjectural formula for the endoscopic contribution. We show how counting curves over finite fields provides us with detailed information about Siegel modular forms.

A. Felikson, P. Tumarkin

Let $G$ be a discrete group generated by reflections in hyperbolic or Euclidean space, and $H\subset G$ be a finite index subgroup generated by reflections. Suppose that the fundamental chamber of $G$ is a finite volume polytope with $k$ facets. In this paper, we prove that the fundamental chamber of $H$ has at least $k$ facets.

Mikhail. A. Lifshits, Thomas Simon

Let R be a symmetric a-stable Riemann-Liouville process with Hurst parameter H > 0. Consider ||.|| a translation invariant, b-self-similar, and p-pseudo-additive functional semi-norm. We show that if H > (b + 1/p) and c = (H - b - 1/p), then x log P [ log ||R|| < c log x ] -> - k < 0, when x -> 0, with k finite in the Gaussian case a = 2. If a < 2, we prove

Richard Hain

This paper is an expanded version of a talk given at the Current Developments in Mathematics Conference last November (2002) on the work of Wilfred Schmid on periods of limits of Hodge structures. The paper begins with an exposition of the theory of limits of Hodge structures with some emphasis on the geometry. It goes on to discuss (briefly) the periods of

Stefan Haller, Cornelia Vizman

For a given manifold $M$ we consider the non-linear Grassmann manifold $Gr_n(M)$ of $n$-dimensional submanifolds in $M$. A closed $(n+2)$-form on $M$ gives rise to a closed 2-form on $Gr_n(M)$. If the original form was integral, the 2-form will be the curvature of a principal $S^1$-bundle over $Gr_n(M)$. Using this $S^1$-bundle one obtains central extensions

Nguyen Van Chau

The non-proper value set of a nonsingular polynomial map from $\C^2$ into itself, if non-empty, must be a curve with one point at infinity.

Melvyn B. Nathanson

Let A be a set of integers. For every integer n, let r_{A,2}(n) denote the number of representations of n in the form n = a_1 + a_2, where a_1 and a_2 are in A and a_1 \leq a_2. The function r_{A,2}: Z \to N_0 \cup {\infty} is the representation function of order 2 for A. The set A is called an asymptotic basis of order 2 if r_{A,2}^{-1}(0) is finite, that i

Jie Qing

In this paper we prove that a conformally compact Einstein manifold with the round sphere as its conformal infinity has to be the hyperbolic space. We do not assume the manifolds to be spin, but our approach relies on the positive mass theorem for asymptotic flat manifolds. The proof is based on understanding of positive eigenfunctions and compactifications

Alice Chang, Jie Qing, Paul Yang

In this paper we provide a criteria for geometric finiteness of Kleinian groups in general dimension. We formulate the concept of conformal finiteness for Kleinian groups in space of dimension higher than two, which generalizes the notion of analytic finiteness in dimension two. Then we extend the argument in the paper of Bishop and Jones to show that confor

Alexander E. Holroyd, Thomas M. Liggett, Dan Romik

We prove that $$\int_0^1\frac{-\log f(x)}xdx=\frac{π^2}{3ab}$$ where $f(x)$ is the decreasing function that satisfies $f^a-f^b=x^a-x^b$, for $0<a<b$. When $a$ is an integer and $b=a+1$ we deduce several combinatorial results. These include an asymptotic formula for the number of integer partitions not having $a$ consecutive parts, and a formula for the metas

Victor M. Villalba, Walter Greiner

We solve the two-component Dirac equation in the presence of a spatially one dimensional symmetric cusp potential. We compute the scattering and bound states solutions and we derive the conditions for transmission resonances as well as for supercriticality.

Jin-Ho Cho, Phillial Oh

We study the rotating tubular D2-brane as a time dependent supersymmetric solution of type-IIA string theory. We show that the Poynting angular momentum of the supertube can be replaced by the mechanical angular momentum without disturbing the 8 supersymmetries. Unlike the non-rotating supertube, whose cross section can take an arbitrary shape, the rotating