July 2006 arXiv papers — page 41

Norbert Nemec, Gianaurelio Cuniberti

The electronic spectrum of a two-dimensional square lattice in a perpendicular magnetic field has become known as the Hofstadter butterfly [Hofstadter, Phys. Rev. B 14, 2239 (1976).]. We have calculated quasi-one-dimensional analogs of the Hofstadter butterfly for carbon nanotubes (CNTs). For the case of single-wall CNTs, it is straightforward to implement m

Zoltan Nagy, Davison E. Soper

Shower Monte Carlo event generators have played an important role in particle physics. Modern experiments would hardly be possible without them. In this talk I discuss how QCD physics is incorporated into the mathematical structure of these programs and I outline recent developments including matching between events with different numbers of hard jets and th

Roberto Emparan, Gary T. Horowitz

We consider vacuum solutions in M theory of the form of a five-dimensional Kaluza-Klein black hole cross T^6. In a certain limit, these include the five-dimensional neutral rotating black hole (cross T^6). From a IIA standpoint, these solutions carry D0 and D6 charges. We show that there is a weakly coupled D-brane description which precisely reproduces the

Eric Huff, A. E. Schulz, Martin White, David J. Schlegel

The coupling of photons and baryons by Thomson scattering in the early universe imprints features in both the Cosmic Microwave Background (CMB) and matter power spectra. The former have been used to constrain a host of cosmological parameters, the latter have the potential to strongly constrain the expansion history of the universe and dark energy. Key to th

I. de Medeiros Varzielas, S. F. King, G. G. Ross

The observed neutrino mixing, having a near maximal atmospheric neutrino mixing angle and a large solar mixing angle, is close to tri-bi-maximal. We argue that this structure suggests a family symmetric origin in which the magnitude of the mixing angles are related to the existence of a discrete non-Abelian family symmetry. We construct a model in which the

Joshua J. Friess, Steven S. Gubser, Georgios Michalogiorgakis, Silviu S. Pufu

We develop the linear equations that describe graviton perturbations of AdS_5-Schwarzschild generated by a string trailing behind an external quark moving with constant velocity. Solving these equations allows us to evaluate the stress tensor in the boundary gauge theory. Components of the stress tensor exhibit directional structures in Fourier space at both

Konstantin B. Zeldovich, Igor N. Berezovsky, Eugene I. Shakhnovich

Prokaryotes living at extreme environmental temperatures exhibit pronounced signatures in the amino acid composition of their proteins and nucleotide compositions of their genomes reflective of adaptation to their thermal environments. However, despite significant efforts, the definitive answer of what are the genomic and proteomic compositional determinants

Robert Brout

Sorkin's causet mechanism is generalized to include energy exchange between causet elements and conventional vacuum fluctuations to the inflationary epoch. In this, the dark energy of the adiabatic era is the fluctuating remnant of inflation. The mechanism is also applicable to black hole evaporation.

D. N. Dias, E. S. Caixeiro, E. V. L. de Mello

A series of recent experiments on the Nernst effect, upper critical field $H_{c2}$ and enhanced diamagnetic magnetization $M$ by Wang et al (PRB 73, 024510), were interpreted as to provide evidence for the pseudogap scenario which long-range phase coherence is destroyed by thermally-created vortices. We present here calculations in good agreement with these

Tina Kahniashvili, Grigol Gogoberidze, Bharat Ratra

We present a unified general formalism for ultraviolet Lorentz invariance violation (LV) testing through electromagnetic wave propagation, based on both dispersion and rotation measure data. This allows for a direct comparison of the efficacy of different data to constrain LV. As an example we study the signature of LV on the rotation of the polarization pla

J. P. Davis, H. Choi, J. Pollanen, W. P. Halperin

Precision measurements of a collective mode in superfluid 3He B are sensitive to quasiparticle and f wave pairing interactions. Measurements were performed at various pressures using interference of transverse sound in an acoustic cavity. We fit the measured collective mode frequencies, which depend on the strength of f wave pairing and the Fermi liquid para

Ming-Hao Liu, Ching-Ray Chang

Electron spin precession in nonuniform Rashba-Dresselhaus two-dimensional electron systems along arbitrary continuous paths is investigated. We derive an analytical formula to describe the spin vectors (expectation values of the injected spin) in such conditions using a contour-integral method. The obtained formalism is capable of dealing with the nonuniform

Andrew S. Toms

We prove stability theorems in the Cuntz semigroup of a commutative C*-algebra which are analogues of classical stability theorems for topological vector bundles over compact Hausdorff spaces. Several applications to simple unital AH algebras of slow dimension growth are then given: such algebras have strict comparison of positive elements; their Cuntz semig

Roberto Ferreiro Perez

The locality conditions for the vanishing of local anomalies in field theory are shown to admit a geometrical interpretation in terms of local equivariant cohomology, thus providing a method to deal with the problem of locality in the geometrical approaches to the study of local anomalies based on the Atiyah-Singer index theorem. The local cohomology is show

M. A. Dantas, J. S. Alcaniz, Deepak Jain, Abha Dev

Dark energy is the invisible fuel that seems to drive the current acceleration of the Universe. Its presence, which is inferred from an impressive convergence of high-quality observational results along with some sucessful theoretical predictions, is also supported by the current estimates of the age of the Universe from dating of local and high-$z$ objects.

A. J. Wagner

Lattice Boltzmann simulations have been very successful in simulating liquid-gas and other multi-phase fluid systems. However, the underlying second order analysis of the equation of motion has long been known to be insufficient to consistently derive the fourth order terms that are necessary to represent an extended interface. These same terms are also resp

Adam H. Marshall

This paper reports numerical studies of a compressible version of the Ising spin glass in two dimensions. Compressibility is introduced by adding a term that couples the spin-spin interactions and local lattice deformations to the standard Edwards-Anderson model. The relative strength of this coupling is controlled by a single dimensionless parameter, mu. Th

J. Kappeli, S. Theisen, P. Vanhove

We study four-dimensional compactifications of type II superstrings on Calabi-Yau spaces in the hybrid formalism. Chiral and twisted-chiral interactions are rederived, which involve the coupling of the compactification moduli to two powers of the Weyl-tensor and of the derivative of the universal tensor field-strength. We review the formalism and provide det

Z. Eker, O. Demircan, S. Bilir, Y. Karatas

Evidence of secular dynamical evolution for detached active binary orbits are presented. First order decreasing rates of orbital angular momentum (OAM), systemic mass ($M=M_{1}+M_{2}$) and orbital period of detached active binaries have been determined as $\dot J/J = -3.48 \times 10^{-10}$yr$^{-1}$, $\dot M/M = -1.30 \times 10^{-10}$yr$^{-1}$ and $\dot P/P =

Mustafa Salti

This paper has been removed by arXiv administrators because it plagiarizes gr-qc/0212018, gr-qc/0501002, and gr-qc/9601044. This paper has excessive overlap with the following papers also written by the authors or their collaborators: gr-qc/0603108, gr-qc/0606022, gr-qc/0603027, gr-qc/0603063, gr-qc/0607083, gr-qc/0607095, gr-qc/0511030, gr-qc/0512080, gr-qc

Igor N. Berezovsky, Konstantin B. Zeldovich, Eugene I. Shakhnovich

The aim of this work is to elucidate how physical principles of protein design are reflected in natural sequences that evolved in response to the thermal conditions of the environment. Using an exactly solvable lattice model, we design sequences with selected thermal properties. Compositional analysis of designed model sequences and natural proteomes reveals

S. Lipari, S. F. Sanchez, M. Bergmann, R. Terlevich

In this work we present the first results of a study of BAL QSOs (at low and high redshift), based on very deep Gemini GMOS integral field spectroscopy. In particular, the results obtained for the nearest BAL IR QSO Mrk 231 are presented. Very deep three-dimensional spectra and maps clearly show that the BAL systems I and II are extended (reaching 1.4-1.6&#3

Avinash Kolli, Brendon W. Lovett, Simon C. Benjamin, Thomas M. Stace

Parity measurements on qubits can generate the entanglement resource necessary for scalable quantum computation. Here we describe a method for fast optical parity measurements on electron spin qubits within coupled quantum dots. The measurement scheme, which can be realised with existing technology, consists of the optical excitation of excitonic states foll

A. P. Bakulev, S. V. Mikhailov, N. G. Stefanis

We work out and discuss the Minkowski version of Fractional Analytic Perturbation Theory (FAPT) for QCD observables, recently developed and presented by us for the Euclidean region. The original analytic approach to QCD, initiated by Shirkov and Solovtsov, is summarized and relations to other proposals to achieve an analytic strong coupling are pointed out.

C. Pacher

An important aspect of resonant tunneling with a probability of unity (thus zero reflection) through a finite region with length l is studied. The relation between the velocity expectation value $<\hat v_{res}>$ restricted to a region of length l and the tunneling time $τ_{res}$ through the same region is calculated. The obtained result is the analogue of th

Jose Javier garcia Moreta

In this paper we present a method to obtain a possible self-adjoint Hamiltonian operator so its energies satisfy Z(1/2+iE_n)=0, which is an statement equivalent to Riemann Hypothesis, first we use the explicit formula for the Chebyshev function Psi(x) and apply the change x=exp(u), after that we consider an Statistical partition function involving the Chebys

Mikiya Masuda, Taras Panov

A Bott tower is the total space of a tower of fibre bundles with base CP^1 and fibres CP^1. Every Bott tower of height n is a smooth projective toric variety whose moment polytope is combinatorially equivalent to an n-cube. A circle action is semifree if it is free on the complement to fixed points. We show that a (quasi)toric manifold (in the sense of Davis

Jessie Shelton, Washington Taylor, Brian Wecht

We consider type II string theory compactified on a symmetric T^6/Z_2 orientifold. We study a general class of discrete deformations of the resulting four-dimensional supergravity theory, including gaugings arising from geometric and &#34;nongeometric&#39;&#39; fluxes, as well as the usual R-R and NS-NS fluxes. Solving the equations of motion associated with

Gustavo P. Saracco, Ezequiel V. Albano

The dynamic behavior of the interfaces in the standard and random driven lattice gas models (DLG and RDLG respectively) is investigated via numerical Monte Carlo simulations in two dimensions. For $T\lesssim T_c$, the average interface width of the strips ($W$) was measured as a function of the lattice size and the anisotropic shape factor. It was found that

Nana Pan, Xiaoping Zheng, Jiarong Li

We calculate the coefficient of bulk viscosity by considering the non-leptonic weak interactions in the cores of hybrid stars with both hyperons and quarks. We first determine the dependence of the production rate of neutrons on the reaction rate of quarks in the non-leptonic processes, that is $Γ_{n}=K_{s}Γ_{s}+Γ_Λ+2Γ_{Σ^{-}}$. The conversion rate, $K_{s}$

Eric M. Rains

In math.QA/0309252, the author proved a number of multivariate elliptic hypergeometric integrals. The purpose of the present note is to explore more carefully the various limiting cases (hyperbolic, trigonometric, rational, and classical) that exist. In particular, we show (using some new estimates of generalized gamma functions) that the hyperbolic integral

Jörn Dunkel, Peter Hänggi

The Langevin equation (LE) for the one-dimensional relativistic Brownian motion is derived from a microscopic collision model. The model assumes that a heavy point-like Brownian particle interacts with the lighter heat bath particles via elastic hard-core collisions. First, the commonly known, non-relativistic LE is deduced from this model, by taking into ac

I. A. Todoshchenko, H. Alles, J. Bueno, H. J. Junes

We have measured the melting curve of $^4$He in the temperature range from 10 to 400 mK with the accuracy of about 0.5 $μ$bar. Crystals of different quality show the expected $T^4$-dependence in the range from 80 to 400 mK without any sign of the supersolid transition, and the coefficient is in excellent agreement with available data on the sound velocity in

F. Haupt, F. Cavaliere, R. Fazio, M. Sassetti

In this paper we report a relaxation-induced suppression of the noise for a single level quantum dot coupled to an oscillator with incoherent dynamics in the sequential tunneling regime. It is shown that relaxation induces qualitative changes in the transport properties of the dot, depending on the strength of the electron-phonon coupling and on the applied

K. Fialkowski

The recent data on the enhancement of the low mass dilepton yield in heavy ion collisions are interpreted as an effect of the &#34;prolonged life&#34; of resonances in the hadron gas phase. The value of the enhancement factor gives an upper limit for the duration time of this phase.

B. J. Powell, Ross H. McKenzie

We study the resonating valence bond (RVB) theory of the Hubbard-Heisenberg model on the half-filled anisotropic triangular lattice. Varying the frustration changes the wavevector of maximum spin correlation in the Mott insulating phase. This, in turn, changes the symmetry of the superconducting state, that occurs at the boundary of the Mott insulating phase

Kaushik Bhattacharya, Subhendra Mohanty, Akhilesh Nautiyal

If inflation was preceded by a radiation era then at the time of inflation there will exist a decoupled thermal distribution of gravitons. Gravitational waves generated during inflation will be amplified by the process of stimulated emission into the existing thermal distribution of gravitons. Consequently the usual zero temperature scale invariant tensor sp

Ayan Mahalanobis

In this paper we study the MOR cryptosystem. We use the group of unitriangular matrices over a finite field as the non-abelian group in the MOR cryptosystem. We show that a cryptosystem similar to the El-Gamal cryptosystem over finite fields can be built using the proposed groups and a set of automorphisms of these groups. We also show that the security of t

Oleg N. German, Evgeniy L. Lakshtanov

The Lagrange theorem on continued fractions states that a number is a quadratic surd if and only if its continued fraction expansion is eventually periodic. The current paper is devoted to a multidimensional generalization of this fact. As a multidimensional analog of continued fractions so called Klein polyhedra are considered: given an irrational lattice i

V. F. Dmitriev, A. I. Milstein

We use the Paris nucleon-antinucleon optical potential for explanation of experimental data in the process $e^+e^- \to p\bar p$ near threshold. It is shown that the cross section and the electromagnetic form factors are very sensitive to the parameters of the potential. It turns out that final-state interaction due to slightly modified absorptive part of the

Jacek Brodzki, Varghese Mathai, Jonathan Rosenberg, Richard J. Szabo

We develop some of the ingredients needed for string theory on noncommutative spacetimes, proposing an axiomatic formulation of T-duality as well as establishing a very general formula for D-brane charges. This formula is closely related to a noncommutative Grothendieck-Riemann-Roch theorem that is proved here. Our approach relies on a very general form of P

Fabio Scardigli

Hawking temperature is computed for a large class of black holes (with spherical, toroidal and hyperboloidal topologies) using only laws of classical physics plus the "classical" Heisenberg Uncertainty Principle. This principle is shown to be fully sufficient to get the result, and there is no need to this scope of a Generalized Uncertainty Principle.

Gil Kalai

We propose and discuss two postulates on the nature of errors in highly correlated noisy physical stochastic systems. The first postulate asserts that errors for a pair of substantially correlated elements are themselves substantially correlated. The second postulate asserts that in a noisy system with many highly correlated elements there will be a strong e

Sudarshan Ananth, Lars Brink, Rainer Heise, Harald G. Svendsen

We conjecture that the light-cone Hamiltonian of N=8 Supergravity can be expressed as a quadratic form. We explain why this rewriting is unique to maximally supersymmetric theories. The N=8 quartic interaction vertex is constructed and used to verify that this conjecture holds to second order in the coupling constant.

BES Collaboration

Using a data sample of $58\times 10^6$ $J/ψ$ decays collected with the BES II detector at the BEPC, searches for invisible decays of $η$ and $η^\prime$ in $J/ψ$ to $ϕη$ and $ϕη^\prime$ are performed. The $ϕ$ signals, which are reconstructed in $K^+K^-$ final states, are used to tag the $η$ and $η^\prime$ decays. No signals are found for the invisible decays

Kirill Krasnov, Jean-Marc Schlenker

The renormalized volume of hyperbolic manifolds is a quantity motivated by the AdS/CFT correspondence of string theory and computed via a certain regularization procedure. The main aim of the present paper is to elucidate its geometrical meaning. We use another regularization procedure based on surfaces equidistant to a given convex surface \partial N. The r

Yongju Bae, Dongseok Kim, Chan-Young Park

We define the basket number, the flat plumbing number and the flat plumbing basket number of a link. Then we provide some upperbounds for these plumbing numbers by using Seifert&#39;s algorithm. We study the relation between these plumbing numbers and the genera of links.

Eckhard Steffen

In 1954, Tutte conjectured that every bridgeless graph has a nowhere-zero 5-flow. Let $ω$ be the minimum number of odd cycles in a 2-factor of a bridgeless cubic graph. Tutte&#39;s conjecture is equivalent to its restriction to cubic graphs with $ω\geq 2$. We show that if a cubic graph $G$ has no edge cut with fewer than $ {5/2} ω- 1$ edges that separates tw

Y. Tamada, Y. Morimoto, S. Yamamoto, M. Takano

We investigated effects of annealing time on structural and magnetic properties of the L10-FePt nanoparticles synthesized by the SiO2-nanoreacter method. The magnetization and powder X-ray diffraction studies revealed that the annealing at 900 oC for 9 hr could convert all of the fcc-nanoparticles to the well-crystallized L10 structure with a large coercivit

Shunsaku Horiuchi, Shin&#39;ichiro Ando

We investigate contributions to the extragalactic gamma-ray background (EGB) due to neutralino dark matter (DM) pair-annihilation into photons, from DM density enhancements (minispikes) surrounding intermediate-mass black holes (IMBHs). We focus on two IMBH formation scenarios; our conservative scenario where IMBHs are remnants of Population-III stars, and o

Tomohiro Yamada

We shall make a slight improvement to a result of p-adic logarithms which gives a nontrivial upper bound for the exponent of p dividing the Fermat quotient x^{p-1}-1.

Guenther Ruediger, Rainer Hollerbach, Frank Stefani, Thomas Gundrum

We study experimentally the flow of a liquid metal confined between differentially rotating cylinders, in the presence of externally imposed axial and azimuthal magnetic fields. For increasingly large azimuthal fields a wave-like disturbance arises, traveling along the axis of the cylinders. The wavelengths and speeds of these structures, as well as the fiel

K. Finlator, R. Dave&#39;, B. Oppenheimer

We conduct a detailed comparison of broad-band spectral energy distributions of six z >= 5.5 galaxies against galaxies drawn from cosmological hydrodynamic simulations. We employ a new tool called SPOC, which constrains the physical properties of observed galaxies through a Bayesian likelihood comparison with model galaxies. For five out of six observed z>=5

N. P. Bobev, R. C. Rashkov

We investigate giant magnons from classical rotating strings in two different backgrounds. First we generalize the solution of Hofman and Maldacena and investigate new magnon excitations of a spin chain which are dual to a string on $R\times S^5$ with two non-vanishing angular momenta. Alowing string dynamics along the third angle in the five sphere, we find

D. J. Mulryne, N. J. Nunes

The computation of the spectrum of primordial perturbations, generated by a scalar field during the super-inflationary phase of Loop Quantum Cosmology, is revisited. The calculation is performed for two different cases. The first considers the dynamics of a massless field and it is found that scale invariance can only be achieved under a severe fine tuning.

Han-Ying Guo, Chao-Guang Huang, Yu Tian, Zhan Xu

There is a one-to-one correspondence between Snyder&#39;s model in de Sitter space of momenta and the \dS-invariant special relativity. This indicates that physics at the Planck length $\ell_P$ and the scale $R=3/Λ$ should be dual to each other and there is in-between gravity of local \dS-invariance characterized by a dimensionless coupling constant $g=\ell_

Kimikazu Kato, Mayumi Oto, Hiroshi Imai, Keiko Imai

For one-qubit pure quantum states, it is already proved that the Voronoi diagrams with respect to two distances -- Euclidean distance and the quantum divergence -- coincide. This fact is a support for a known method to calculate the Holevo capacity. To consider an applicability of this method to quantum states of a higher level system, it is essential to che

Wan-Ying Wang, Bin Shang, Chuan Wang, Gui Lu Long

We give algorithms to factorize large integers in the duality computer. We provide three duality algorithms for factorization based on a naive factorization method, the Shor algorithm in quantum computing, and the Fermat&#39;s method in classical computing. All these algorithms are polynomial in the input size.

Taras V. Fityo

We consider one dimensional deformed Heisenberg algebra leading to existence of minimal length for coordinate operator and minimal and maximal uncertainty of momentum operator. For this algebra an exactly solvable Hamiltonian is constructed.

F. D. Mazzitelli, X. Orsi Millan

We study the photon creation inside a perfectly conducting, spherical oscillating cavity. The electromagnetic field inside the cavity is described by means of two scalar fields which satisfy Dirichlet and (generalized) Neumann boundary conditions. As a preliminary step, we analyze the dynamical Casimir effect for both scalar fields. We then consider the full

Sergei P. Lukyanets, Dmytro A. Bevzenko

We study effects of direct interatomic interaction on cooperative processes in atom-photon dynamics. Using a model of two-level atoms with Ising-type interaction as an example, it is demonstrated that interparticle interaction combined with atom-field coupling can introduce additional interatomic correlations acting as a phase synchronizing factor. For the c

Alina Dubrovska Vasilieva, Taisija Mischenko-Slatenkova

In this paper we study the complexity of quantum query algorithms computing the value of Boolean function and its relation to the degree of algebraic polynomial representing this function. We pay special attention to Boolean functions with quantum query algorithm complexity lower than the deterministic one. Relation between the degree of representing polynom

Fail M. Gafarov

We propose a model for description of activity-dependent evolution and self-wiring between binary neurons. Specifically, this model can be used for investigation of growth of neuronal connectivity in the developing neocortex. By using computational simulations with appropriate training pattern sequences, we show that long-term memory can be encoded in neuron

A. I. Rahachou, I. V. Zozoulenko

We study propagation of TM- and TE-polarized light in two-dimensional arrays of silver nanorods of various diameters in a gelatin background. We calculate the transmittance, reflectance and absorption of arranged and disordered nanorod arrays and compare the exact numerical results with the predictions of the Maxwell-Garnett effective-medium theory. We show

Eric W. Holman, Christian Schulze, Dietrich Stauffer, Soren Wichmann

The recent availability of larger typological databases such as Haspelmath et al. (2005) has brought the linguistics community closer to having a solid, empirical foundation for making actual claims about prehistoric migrations, deep genealogical relationship, and patterns of areal linguistic interaction. Nevertheless, still more data are needed, and more th

Bernhard Rothenstein, Stefan Popescu

We consider the problem of the period measurement in the case of the following scenarios: stationary source of successive light signals and accelerating receiver, stationary receiver and accelerating source of successive light signals and stationary machine gun that fires successive bullets received by an accelerating receiver. The accelerated motion is the

Neil V. Budko, Alexander B. Samokhin

We derive the essential space-time spectrum of the Maxwell equations in linear isotropic inhomogeneous media together with the corresponding essential modes. These modes represent the collapse of the electromagnetic field into a single point in space at a single angular frequency. The location and frequency of the essential mode are random variables obeying

Milutin Stepic, Eugene Smirnov, Christian E. Rueter, Vladimir Shandarov

The interaction between two parallel beams in one-dimensional discrete saturable systems has been investigated using lithium niobate nonlinear waveguide arrays. When the beams are separated by one channel and in-phase it is possible to observe soliton fusion at low power levels. This new result is confirmed numerically. By increasing the power, soliton-like

R. Antolini, R. Baldini Ferroli, M. Caporaloni, A. Chiavassa

The new experiment ``Extreme Energy Events&#39;&#39; (EEE) to detect extensive air showers through muon detection is starting in Italy. The use of particle detectors based on Multigap Resistive Plate Chambers (MRPC) will allow to determine with a very high accuracy the direction of the axis of cosmic ray showers initiated by primaries of ultra-high energy, t

Jean-Paul Giovanangeli, Christian Kharif, Julien Touboul

The effect of the wind on the sustain of extreme water waves is investigated experimentally and numerically. A series of experiments conducted in the Large Air-Sea Interactions Facility (LASIF) showed that a wind blowing over a strongly nonlinear short wave group due to the linear focusing of a modulated wave train may increase the life time of the extreme w

M. Baylac, J. M. De Conto, E. Froidefond, E. Sargsyan

LINAC 4 is a normal conducting H- linac proposed at CERN to provide a higher proton flux to the CERN accelerator chain. It should replace the existing LINAC 2 as injector to the Proton Synchrotron Booster and can also operate in the future as the front end of the SPL, a 3.5 GeV Superconductingg Proton Linac. LINAC 4 consists of a Radio-Frequency Quadrupole,

Evangelos Matsinos, Wolfgang Kaissl

We describe a method aiming at increasing the dynamic range of X-ray detectors. Two X-ray exposures of an object are acquired at different dose levels and constitute the only input data. The values of the parameters which are needed to process these images are determined from information contained in the images themselves; the values of two parameters are ex

M. Baylac, J. M. De Conto, E. Froidefond, E. Sargsyan

LINAC 4 is a normal conducting H- structure proposed to intensify the proton flux currently available for the CERN accelerator chain. This linac is designed to accelerate a 65 mA beam up to 160 MeV to be injected into the CERN Proton Synchrotron Booster. The acceleration is performed up to 3 MeV by a Radio-Frequency Quadrupole resonating at 352 MHz followed

Ricardo Coelho, Claire G. Gilmore, Brian Lucey, Peter Richmond

The minimum spanning tree is used to study the process of market integration for a large group of national stock market indices. We show how the asset tree evolves over time and describe the dynamics of its normalized length, mean occupation layer, and single- and multiple-step linkage survival rates. Over the period studied, 1997-2006, the tree shows a tend

Evangelos Matsinos, Wolfgang Kaissl

Varian Medical Systems has manufactured and recently put into operation a clinically-applicable solution for image-guided radiation therapy. Cone-beam CT imaging, one of the operation modes of the imaging unit of this device, aims at high-quality volumetric reconstruction. To boost the image quality, the dual-gain mode, a successful means for enhancing the d

P. H. Chavanis

We discuss the structure of the equilibrium states of a regularized Keller-Segel model describing the chemotaxis of bacterial populations. We consider the limit of high degradation of the secreted chemical where analytical results can be obtained. Below a critical effective temperature, the system experiences a second order phase transition from a homogeneou

Julius Vanko, Miroslav Sukenik, Jozef Sima

Stemming from simple postulates of nondecelerative nature of the universe expansion and Vaidya metric application, the paper offers some dependences and relations between the gravity and weak interactions. It presents a mode of independent determination of the mass of vector bosons Z and W, and it derives the time of separation of electromagnetic and weak in

Evangelos Matsinos, Wolfgang Kaissl

We propose a method to achieve the geometric calibration of cone-beam imaging and delivery systems in radiation therapy; our approach applies to devices where an X-ray source and a flat-panel detector, facing each other, move in circular orbits around the irradiated object. In order to extract the parameters of the geometry from the data, we use a light need

Akinbo Ojo

We describe a thought experiment using an isolated system of known parameters and assuming the correctness of Clausius and Boltzmann descriptions of entropy. The experiment produced an astronomical increase in the number of possible ways the system can be arranged and inescapably in achieving this, an increase in the compartment volume of the system. The res

Satoshi Sunada, Takahisa Harayama

The Sagnac effect in two dimensional (2D) resonant microcavities is studied theoretically and numerically. The frequency shift due to the Sagnac effect occurs as a threshold phenomenon for the angular velocity in a rotating microcavity. Above the threshold, the eigenfunctions of a rotating microcavity become rotating waves while they are standing waves below

Y. Liu, J. D. Richardson, J. W. Belcher, J. C. Kasper

We find that the sheath regions between fast interplanetary coronal mass ejections (ICMEs) and their preceding shocks are often characterized by plasma depletion and mirror wave structures, analogous to planetary magnetosheaths. A case study of these signatures in the sheath of a magnetic cloud (MC) shows that a plasma depletion layer (PDL) coincides with ma

C. Cabeza, Gustavo Sarasua, Arturo C. Marti, Italo Bove

This work is focused to study the development and control of the laminar vortex breakdown of a flow enclosed in a cylinder. We show that vortex breakdown can be controlled by the introduction of a small fixed rod in the axis of the cylinder. Our method to control the onset of vortex breakdown is simpler than those previously proposed, since it does not requi

Frank Boettcher, Joachim Peinke, David Kleinhans, Rudolf Friedrich

This article reports on a new approach to properly analyze time series of dynamical systems which are spoilt by the simultaneous presence of dynamical noise and measurement noise. It is shown that even strong external measurement noise as well as dynamical noise which is an intrinsic part of the dynamical process can be quantified correctly, solely on the ba

Søren Fournais, Maria Hoffmann-Ostenhof, Thomas Østergaard Sørensen

We study electron densities of eigenfunctions of atomic Schroedinger operators. We prove the existence of rho~&#39;&#39;&#39;(0), the third derivative of the spherically averaged atomic density rho~ at the nucleus. For eigenfunctions with corresponding eigenvalue below the essential spectrum we obtain the bound rho~&#39;&#39;&#39;(0) \leq -(7/12)Z^3 rho~(0),

Roldao da Rocha, Waldyr A. Rodrigues

In this paper using the apparatus of the Clifford bundle formalism we show how straightforwardly solve in Minkowski spacetime the Dirac-Hestenes equation -- which is an appropriate representative in the Clifford bundle of differential forms of the usual Dirac equation -- by separation of variables for the case of a potential having spherical symmetry in the

Hitoshi Kitada

Fundamental solution for a Schrödinger equation with a time-dependent potential of long-range type is constructed. The solution is given as a Fourier integral operator with a symbol uniformly bounded global in time, when measured in natural semi-norms of a symbol class.

Tim Van der Linden

The theory of abelian categories proved very useful, providing an axiomatic framework for homology and cohomology of modules over a ring and, in particular, of abelian groups. For many years, a similar categorical framework has been lacking for non-abelian (co)homology, the subject of which includes the categories of non-abelian groups, of rings, Lie algebra

Xianping Guo, Ulrich Rieder

This paper is devoted to studying the average optimality in continuous-time Markov decision processes with fairly general state and action spaces. The criterion to be maximized is expected average rewards. The transition rates of underlying continuous-time jump Markov processes are allowed to be unbounded, and the reward rates may have neither upper nor lowe

Pao-Liu Chow

Large-time asymptotic properties of solutions to a class of semilinear stochastic wave equations with damping in a bounded domain are considered. First an energy inequality and the exponential bound for a linear stochastic equation are established. Under appropriate conditions, the existence theorem for a unique global solution is given. Next the questions o

Mehdi Hassani

In this note, we show that there are many infinity positive integer values of $n$ in which, the following inequality holds $$ \left\lfloor{1/2}(\frac{(n+1)^2}{\log(n+1)}-\frac{n^2}{\log n})-\frac{\log^2 n}{\log\log n}\right\rfloor\leqπ\big((n+1)^2\big)-π(n^2). $$

Edmundo Rofman, Melina Rapacioli, Vladimir Flores

The present work is devoted to describe a set of rules explaining the discriminating versus non-discriminating behavior of the di-basic stages and to characterize the role of each base in determining such a behavior. Bases are analyze as dual entities characterized by its chemical type and the number of H bonds involved in the codon-anticodon interaction. A

B. Feigin, E. Feigin

In this paper we study a family of commutative algebras generated by two infinite sets of generators. These algebras are parametrized by Young diagrams. We explain a connection of these algebras with the fusion product of integrable irreducible representations of the affine $sl_2$ Lie algebra. As an application we derive a fermionic formula for the character

Erling Stormer

Let $ϕ$ be a positive unital normal map of a von Neumann algebra $M$ into itself, and assume there is a family of normal $ϕ$-invariant states which is faithful on the von Neumann algebra generated by the image of $ϕ$. It is shown that there exists a largest Jordan subalgebra $C_ϕ$ of $M$ such that the restriction of $ϕ$ to $C_ϕ$ is a Jordan automorphhism, an

S. Ekisheva, C. Houdré

For probability measures on a complete separable metric space, we present sufficient conditions for the existence of a solution to the Kantorovich transportation problem. We also obtain sufficient conditions (which sometimes also become necessary) for the convergence, in transportation, of probability measures when the cost function is continuous, non-decrea

Adam N. Letchford, Dirk Oliver Theis

The famous Padberg-Rao separation algorithm for b-matching polyhedra can be implemented to run in O(n^2m log(n^2/m)) time in the uncapacitated case, and in O(nm^2 log(n^2/m)) time in the capacitated case (where n is the number of vertices and m is the number of edges of the underlying graph). We give a new and simple algorithm for the capacitated case which

Eli Aljadeff, Ángel del Río

We prove that any projective Schur algebra over a field $K$ is equivalent in $Br(K)$ to a radical abelian algebra. This was conjectured in 1995 by Sonn and the first author of this paper. As a consequence we obtain a characterization of the projective Schur group by means of Galois cohomology. The conjecture was known for algebras over fields of positive cha

S. Koetzer, I. Molchanov

We consider the classical Wicksell corpuscle problem with spherical particles in R^n and investigate the shapes of lower tails of distributions of `sphere radii&#39; in R^n and `sphere radii&#39; in a k-dimensional section plane. We show in which way the domains of attraction are related to each other.

Masatoshi Enomoto, Yasuo Watatani

We study the relative position of four subspaces in a Hilbert space. For any positive integer n, we give an example of exotic indecomposable system of four subspaces in a Hilbert space whose defect is (2n+1)/3. By an exotic system, we mean a system which is not isomorphic to any closed operator system under any permutation of subspaces. We construct the exam

S. K. Donaldson

We define a general class of elliptic equations for 2-forms on 4-manifolds, of which the complex Monge-Ampere equation is a prototype. We obtain some regularity results and discuss various connections (some speculative) with modern symplectic 4-manifold theory.

Elemer E Rosinger

Ideals of continuous functions which satisfy an off diagonality condition proved to be important connected with the solution of large classes of nonlinear PDEs, and more recently, in General Relativity and Quantum Gravity. Maximal ideals within those which satisfy that off diagonality condition are important since they lead to differential algebras of genera