August 2000 arXiv papers — page 18

E. O. Iltan, G. Turan

We study the decay width and forward-backward asymmetry of the lepton pair for the inclusive decay b --> s τ^+ τ^- in the two Higgs doublet model with three level flavor changing neutral currents (model III) and analyse the dependencies of these quantities on the model III parameters, including the leading order QCD corrections. We found that there is a cons

Keshav Dasgupta, Seungjoon Hyun, Kyungho Oh, Radu Tatar

We study D3 branes at orbifolded conifold singularities in the presence of discrete torsion. The vacuum moduli space of open strings becomes non-commutative due to a deformation of the superpotential and is studied via the representation theory of the moduli algebra. It is also shown that the center of the moduli algebra correctly describes the underlying or

B. C. Travaglione, G. J. Milburn

The phase estimation algorithm is so named because it allows the estimation of the eigenvalues associated with an operator. However it has been proposed that the algorithm can also be used to generate eigenstates. Here we extend this proposal for small quantum systems, identifying the conditions under which the phase estimation algorithm can successfully gen

H. J. Kimble, Yuri Levin, Andrey B. Matsko, Kip S. Thorne

The LIGO-II gravitational-wave interferometers (ca. 2006--2008) are designed to have sensitivities at about the standard quantum limit (SQL) near 100 Hz. This paper describes and analyzes possible designs for subsequent, LIGO-III interferometers that can beat the SQL. These designs are identical to a conventional broad-band interferometer (without signal rec

Takeshi Chiba, Takashi Nakamura

We investigate the feasibility of the method for reconstructing the equation of state and the effective potential of the quintessence field from SNIa data. We introduce a useful functional form to fit the luminosity distance with good accuracy (the relative error is less than 0.1%). We assess the ambiguity in reconstructing the equation of state and the effe

Zurab Berezhiani, Denis Comelli, Francesco L. Villante

There can exist a parallel `mirror' world which has the same particle physics as the observable world and couples the latter only gravitationally. The nucleosynthesis bounds demand that the mirror sector should have a smaller temperature than the ordinary one. By this reason its evolution should be substantially deviated from the standard cosmology as fa

Ing-Guey Jiang, Wing-Huen Ip

The bright F8 V solar-type star upsilon Andromedae has recently been reported to have a system of three planets of Jovian masses. In order to investigate the orbital stability and mutual gravitational interactions among these extrasolar planets, both forward and backward integrations from the latest observed orbital elements for all three planets' orbits

N. J. Cerf, M. Levy, G. Van Assche

A continuous key distribution scheme is proposed that relies on a pair of canonically conjugate quantum variables. It allows two remote parties to share a secret Gaussian key by encoding it into one of the two quadrature components of a single-mode electromagnetic field. The resulting quantum cryptographic information vs disturbance tradeoff is investigated

Seth Lloyd

Necessary and sufficient conditions are given for the construction of a hybrid quantum computer that operates on both continuous and discrete quantum variables. Such hybrid computers are shown to be more efficient than conventional quantum computers for performing a variety of quantum algorithms, such as computing eigenvectors and eigenvalues.

Nathan W. Panike

A bound on the error introduced by truncating a quantum addition is given. This bound shows that only a few controlled rotation gates will be necessary to get a reliable computation.

David P. DiVincenzo, Barbara M. Terhal

We review the role of product bases in quantum information theory. We prove two conjectures which were made in DiVincenzo et al., quant-ph/9908070, namely the existence of two sets of bipartite unextendible product bases, in arbitrary dimensions, which are based on a tile construction. We pose some questions related to complete product bases.

Roger A. Richardson, Stephen Sampayan, John T. Weir

The so-called roll bar measurement uses a heavy metal material, optically thick to x-rays, to form a shadow of the x-ray origination spot. This spot is where an energetic electron beam interacts with a high Z target. The material (the "roll bar") is slightly curved to avoid alignment problems. The roll bar is constructed and positioned so that the x-

R. Chehab, R. Cizeron, C. Sylvia, V. Baier

Numerical simulations and `proof of principle' experiments showed clearly the interest of using crystals as photon generators dedicated to intense positron sources for linear colliders. An experimental investigation, using a 10 GeV secondary electron beam, of the SPS-CERN, impinging on an axially oriented thick tungsten crystal, has been prepared and ope

M. Kuriki, H. Hayano, T. Naito, T. Okugi

KEK-ATF is studying low emittance, multi-bunch electron beam for the future linear collider. The energy instability of the 1.5 GeV linac has been a problem making the beam injection to the damping ring unstable. Because the unstable beam generates also large amount of the radiation, the beam current is limited by the KEK radiation safety policy much lower th

C. Bennhold, A. Waluyo, H. Haberzettl, T. Mart

Resonances with strong couplings to strangeness channels are investigated in a coupled-channels framework of kaon production with pions and photons. We find evidence for an additional D13 resonance around 1900 MeV that has a significant decay width into the K Lambda final state. Such a state has been predicted in a relativistic quark model at 1960 MeV with s

A. Waluyo, C. Bennhold, H. Haberzettl, G. Penner

An effective Lagrangian model in a coupled channels framework is applied to extract nucleon resonance parameters. In the K-matrix approximation, we simultaneously analyze all the available data for the transitions from pi N to five possible meson-baryon final states, pi N, pipi N, eta N, K Lambda, and KSigma, in the energy range from pi N threshold up to W =

D. Knödler, H. Müther

Contributions of nucleon-nucleon (NN) correlations, meson exchange currents and the residual final state interactions (FSI) on exclusive two-nucleon knock-out reactions induced by electron scattering are investigated. All contributions are derived from the same realistic meson exchange model for the NN interaction. Effects of correlations and FSI are determi

Chandrashekar Devchand, Jeremy Schiff

We discuss the possible relationship between geodesic flow, integrability and supersymmetry, using fermionic extensions of the KdV equation, as well as the recently introduced supersymmetrisation of the Camassa-Holm equation, as illustrative examples.

Israel Gelfand, Sergei Gelfand, Vladimir Retakh

This is a first of our papers devoted to "noncommutative topology and graph theory". Its origin is the paper math.QA/0002238 by I. Gelfand, V. Retakh, and R.L. Wilson where a new class of noncommutative algebras $Q_n$ was introduced. The algebra $Q_n$ is closely related to factorizations of a generic polynomial of degree $n$ over a division algebra i

Philippe Elbaz-Vincent, Herbert Gangl, Maxim Kontsevich

We investigate a connection between the differential of polylogarithms (as considered by Cathelineau) and a finite variant of them. This allows to answer a question raised by Kontsevich concerning the construction of functional equations for the finite analogs, using in part the p-adic version of polylogarithms and recent work of Besser. Kontsevich's ori

Mark S. Ashbaugh, Rafael D. Benguria

For a domain $Ω$ contained in a hemisphere of the $n$-dimensional sphere $\SS^n$ we prove the optimal result $λ_2/λ_1(Ω) \le λ_2/λ_1(Ω^{\star})$ for the ratio of its first two Dirichlet eigenvalues where $Ω^{\star}$, the symmetric rearrangement of $Ω$ in $\SS^n$, is a geodesic ball in $\SS^n$ having the same $n$-volume as $Ω$. We also show that $λ_2/λ_1$ for

Mark S. Ashbaugh

This paper reviews many of the known inequalities for the eigenvalues of the Laplacian and bi-Laplacian on bounded domains in Euclidean space. In particular, we focus on isoperimetric inequalities for the low eigenvalues of the Dirichlet and Neumann Laplacians and of the vibrating clamped plate problem (i.e., the biharmonic operator with ``Dirichlet'&#39

Hans U. Boden, Christopher M. Herald, Paul A. Kirk

We define an integer valued invariant of homology spheres using the methods of SU(3) gauge theory and study its behavior under orientation reversal and connected sum.

Franz Lehner

We use free probability techniques to compute borders of spectra of non hermitian operators in finite von Neumann algebras which arise as `free sums' of `simple' operators. To this end, the resolvent is analyzed with the aid of the Haagerup inequality. Concrete examples coming from reduced C*-algebras of free product groups and leading to systems of

Gomari Buanani Naufal

In this paper we consider a robust identification problem for a linear dynamical control system with limited-frequency intervals. In mathematical terms, this is the problem of recovering functions in Hardy spaces. Our purpose is to bound Patil's approximants in the upper half plane case, out of a bounded real interval $I$. To this end, we deal with resid

Nicolae Manolache

One describes those double structures on rational normal curves which are defined scheme theoretically by quadratic equations and have linear syzygies, generalizing this way the double line in the plane

Ruslan Sharipov

Class of Newtonian dynamical systems admitting normal blow-up of points in Riemannian manifolds is considered. Geometric interpretation for weak normality condition, which arose earlier in the theory of dynamical systems admitting the normal shift of hypersurfaces, is found.

Nicolas Moeller

We present some solutions for lumps in two dimensions in level-expanded string field theory, as well as in two tachyonic theories: pure tachyonic string field theory and pure $ϕ^3$ theory. Much easier to handle, these theories might be used to help understanding solitonic features of string field theory. We compare lump solutions between these theories and w

C. Neves, C. Wotzasek

In this paper we quantize the free-particle on a D-dimensional sphere in an unambiguous way by converting the second-class constraint using Stückelberg field shiftting formalism. Further, we argument that this formalism is equivalent to the BFFT constraint conversion method and show that the energy spectrum is identical to the pure Laplace-Beltrami operator

S. Groot Nibbelink, T. S. Nyawelo, J. W. van Holten

This paper discusses a procedure for the consistent coupling of gauge- and matter superfields to supersymmetric sigma-models on symmetric coset spaces of Kaehler type. We exhibit the finite isometry transformations and the corresponding Kaehler transformations. These lead to the construction of a generalized type of Killing potentials. In certain cases a cha

A. Smailagic, E. Spallucci

We show that dualization of BF models to Stueckelberg-like massive gauge theories allows a non-Abelian extension. We obtain local Lagrangians which are straightforward extensions of the Abelian results.

Wang-Chang Su

Faddeev and Niemi have proposed a decomposition of SU(N) Yang-Mills theory in terms of new variables, appropriate for describing the theory in the infrared limit. We extend this method to SO(2N) Yang-Mills theory. We find that the SO(2N) connection decomposes according to irreducible representations of SO(N). The low energy limit of the decomposed theory is

X. Song

The spin and orbital angular momentum carried by different quark flavors in the nucleon are calculated in the SU(3) chiral quark model with symmetry-breaking. The model is extended to all octet and decuplet baryons. In this model, the reduction of the quark spin, due to the spin dilution in the chiral splitting processes, is transferred into the orbital moti

Keith G. Richardson

Various aspects of the application of Effective Field Theory (EFT) to the Nucleon-Nucleon (NN) interaction are considered. We look for contributions beyond One Pion Exchange which are predicted by Chiral Symmetry. Using the formalism of the Wilson Renormalisation Group (RG) we review power counting in a simplified EFT containing only nucleons. For weak scatt

Marco A. Díaz, Stephen F. King, Douglas A. Ross

We study radiative corrections to chargino production at linear colliders with polarised electron beams. We calculate the one-loop corrected cross-sections for polarised electon beams due to three families of quarks and squarks, working in the $\bar{MS}$ scheme, extending our previous calculation of the unpolarised cross-section with one-loop corrections due

David B. Kaplan, Mark B. Wise

Experimental discovery of the dilaton would provide strong evidence for string theory. A light dilaton could show up in current tests of the inverse square law for gravity at sub-millimeter distances. In the large extra dimension scenario, Kaluza-Klein excitations of the dilaton can also contribute to the cooling of supernovae. In order to quantify these eff

J. Bernabeu, L. G. Cabral-Rosetti, J. Papavassiliou, J. Vidal

Using the pinch technique we construct at one-loop order a neutrino charge radius, which is finite, depends neither on the gauge-fixing parameter nor on the gauge-fixing scheme employed, and is process-independent. This definition stems solely from an effective proper photon-neutrino one-loop vertex, with no reference to box or self-energy contributions. The

H. Kröger, X. Q. Luo, K. J. M. Moriarty

We discuss $QCD$ in the Hamiltonian frame work. We treat finite density $QCD$ in the strong coupling regime. We present a parton-model inspired regularisation scheme to treat the spectrum ($θ$-angles) and distribution functions in $QED_{1+1}$. We suggest a Monte Carlo method to construct low-dimensionasl effective Hamiltonians. Finally, we discuss improvemen

Michele Maggiore

We review the motivations for the search of stochastic backgrounds of gravitational waves and we compare the experimental sensitivities that can be reached in the near future with the existing bounds and with the theoretical predictions.

K. K. Nandi, A. Bhadra, P. M. Alsing, T. B. Nayak

We investigate here the behavior of a few spherically symmetric static acclaimed black hole solutions in respect of tidal forces in the geodesic frame. It turns out that the forces diverge on the horizon of cold black holes (CBH) while for ordinary ones, they do not. It is pointed out that Kruskal-like extensions do not render the CBH metrics nonsingular. We

Masahito Ueda

The Bogoliubov theory of weakly interacting bosons is generalized to Bose-Einstein condensates with internal degrees of freedom so that a single effective Hamiltonian produces various many-body ground states or metastable spin domains and the corresponding collective modes on an equal footing.

Cristina Bena, Smitha Vishveshwara, Leon Balents, Matthew P. A. Fisher

The Luttinger model of the one-dimensional Fermi gas is the cornerstone of modern understanding of interacting electrons in one dimension. In fact, the enormous class of systems whose universal behavior is adiabatically connected to it are now deemed Luttinger liquids. Recently, it has been shown that metallic single-walled carbon nanotubes are almost perfec

D. Poulios, N. P. Bigelow, J. P. Spoonhower

The relationship between paramagnetic defect centers and UV absorption bands simultaneously generated by ionizing radiation in Ge-doped SiO2 glass is investigated using magneto-optical techniques. A sample of 7.0 mol% Ge-doped SiO2 was exposed to X-ray radiation, which resulted in the formation of absorption bands centered at 4.4 eV and 5.7 eV as well as ele

Leo Radzihovsky, Erwin Frey, David R. Nelson

We investigate two-dimensional (2d) melting in the presence of a one-dimensional (1d) periodic potential as, for example, realized in recent experiments on 2d colloids subjected to two interfering laser beams. The topology of the phase diagram is found to depend primarily on two factors: the relative orientation of the 2d crystal and the periodic potential t

Maziar Nekovee, W. M. C. Foulkes, R. J. Needs

We use variational quantum Monte Carlo to calculate the density-functional exchange-correlation hole n_{xc}, the exchange-correlation energy density e_{xc}, and the total exchange-correlation energy E_{xc}, of several electron gas systems in which strong density inhomogeneities are induced by a cosine-wave potential. We compare our results with the local den

Vladimir V. Konotop, Victor M. Perez-Garcia

We develop the multiscale technique to describe excitations of a Bose-Einstein condensate (BEC) whose characteristic scales are comparable with the healing length, thus going beyond the conventional hydrodynamical approximation. As an application of the theory we derive approximate explicit vortex and other solutions. The dynamical stability of the vortex is

Haye Hinrichsen

Recently, Lipowski [cond-mat/0002378] investigated a stochastic lattice model which exhibits a discontinuous transition from an active phase into infinitely many absorbing states. Since the transition is accompanied by an apparent power-law singularity, it was conjectured that the model may combine features of first- and second-order phase transitions. In th

Iwan Jensen

A closed plane meander of order $n$ is a closed self-avoiding curve intersecting an infinite line $2n$ times. Meanders are considered distinct up to any smooth deformation leaving the line fixed. We have developed an improved algorithm, based on transfer matrix methods, for the enumeration of plane meanders. While the algorithm has exponential complexity, it

H. Y. Lee, H. -W. Lee, D. Kim

We analyze traffic data from a highway section containing one effective on-ramp. Based on two criteria, local velocity variation patterns and expansion (or nonexpansion) of congested regions, three distinct congested traffic states are identified. These states appear at different levels of the upstream flux and the on-ramp flux, thereby generating a phase di

Tsuyoshi Hondou, Ken Sekimoto

We discuss the reversibility of Brownian heat engine. We perform asymptotic analysis of Kramers equation on Büttiker-Landauer system and show quantitatively that Carnot efficiency is inattainable even in a fully overdamping limit. The inattainability is attributed to the inevitable irreversible heat flow over the temperature boundary.

A. J. Connolly, C. Genovese, A. W. Moore, R. C. Nichol

In this paper, we outline the use of Mixture Models in density estimation of large astronomical databases. This method of density estimation has been known in Statistics for some time but has not been implemented because of the large computational cost. Herein, we detail an implementation of the Mixture Model density estimation based on multi-resolutional KD

Joel Welling, Mark Derthick

Visualization techniques are well developed for many problem domains, but these systems break down for datasets which are very large or multidimensional. Techniques for data which is discrete rather than continuous are also less well studied. Astronomy datasets like the Sloan Digital Sky Survey are very much in this category. We propose the extension of info

C. Sneden, J. J. Cowan

The long-lived radioactive element thorium can potentially provide a simple and direct clock to determine the age of our Galaxy. Spectroscopic investigations of thorium in metal-poor stars have yielded some promising initial results. We discuss the major observational and theoretical limitations in thorium cosmochronometry, and point out the ways in which th

Jorick S. Vink, Alex de Koter, Henny J. G. L. M. Lamers

We have calculated mass-loss rates for a grid of wind models covering a wide range of stellar parameters and have derived a mass-loss recipe for two ranges of effective temperature at either side of the bi-stability jump around spectral type B1. For a large sample of O stars, it is shown that there is now good agreement between these new theoretical mass-los

David K. Strickland, Timothy M. Heckman, Kimberly A. Weaver, Michael Dahlem

Arcsecond-resolution X-ray imaging of the nucleus of the nearby starburst galaxy NGC 253 with Chandra reveals a well-collimated, strongly limb-brightened, kiloparsec-scale conical outflow from the central starburst region. The outflow is very similar in morphology to the known H-alpha outflow cone, on scales down to <= 20 pc. This provides, for the first tim

R. J. Wilman, A. C. Fabian, P. Gandhi

The two brightest hard X-ray sources discovered serendipitously by Chandra in the field of the lensing cluster A2390 are found to have ISOCAM counterparts at 6.7 and 15 micron. We use this fact, together with their non-detection by SCUBA at 850 micron, as the basis for DUSTY radiative transfer modelling of their infrared spectral energy distributions. For th

A. Thion, Y. Mellier, F. Bernardeau, E. Bertin

We explore the stability of the variance and skewness of the cosmic gravitational convergence field, using two different approaches: first we simulate a whole MEGACAM survey (100 sq. degrees). The reconstructed mass map, obtained from a shear map, shows that the state-of-the-art data analysis methods can measure weak-lensing statistics at angular scales rang

R. Maoli, Y. Mellier, L. van Waerbeke, P. Schneider

We report on the detection of cosmic shear on angular scales of 1.3-6.5 arcmin using 45 independent empty fields observed with the Very Large Telescope (VLT). This result confirms previous measurements obtained with the CFH Telescope at the same angular scales. We present the data analysis and the first preliminary results.

L. van Waerbeke, Y. Mellier, T. Erben, J. -C. Cuillandre

We present results of our cosmic shear survey in progress at the Canada- France-Hawaii Telescope (CFHT). We analysed 1.7 sq. degrees of data, out of which we measured a significant correlation of galaxy shape-orientation over several arcmin scale. We present measurements of the variance of the shear $<γ^2>$ and of the correlation functions $<e_r(θ)e_r(0)>$,

Y. F. Huang

We have found that the conventional generic dynamical model for gamma-ray bursts (GRBs) cannot reproduce the Sedov solution in the non-relativistic limit. Based on our refined generic dynamical model, we investigate afterglows from jetted GRB remnants numerically. Many new results are reached. For example, we find no obvious break in the optical light curve

L. Vasiliev, S. Trudolyubov, M. Revnivtsev

We present an analysis of the RXTE observations of X-ray transient source XTE J2012+381 during its 1998 outburst. The spectral and timing properties of the source emission and their evolution during the outburst are very similar to what of the X-ray Novae.

H. Sudou, Y. Taniguchi, Y. Ohyama, S. Kameno

In order to investigate the genesis of powerful radio jet, we have mapped the central 10 pc region of the nearby radio galaxy NGC 6251 with a 0.2 pc resolution using Very Long Baseline Interferometer (VLBI) at two radio frequencies, 5 GHz and 15 GHz, we have found the sub-parsec-scale counterjet for the first time in this radio galaxy. This discovery allows

Celine Peroux, Mike J. Irwin, Richard G. McMahon, Lisa J. Storrie-Lombardi

The results of a new spectroscopic survey of 66 $z \simgt 4$ quasars for Damped Lyman-alpha absorption systems are presented. The search led to the discovery of 30 new DLA candidates which are analysed in order to compute the comoving mass density of neutral gas in a non-zero lambda Universe. The possible sources of uncertainty are discussed and the implicat

Cheng-Pin Chen, Ing-Guey Jiang

The size distribution is determined directly from the current known Kuiper Belt Objects (KBOs). We found that there is a peak for the size distribution around 230 km in diameter. For the objects larger than 230 km, the KBOs populate as $N(s) \propto s^{-4}$ as we see in Jewitt et al. (1998). For the objects smaller than 230 km, we found $N(s) \propto s^{3}$.

David A. van Dyk, Alanna Connors, Vinay L. Kashyap, Aneta Siemiginowska

Over the past 10 years Bayesian methods have rapidly grown more popular as several computationally intensive statistical algorithms have become feasible with increased computer power. In this paper, we begin with a general description of the Bayesian paradigm for statistical inference and the various state-of-the-art model fitting techniques that we employ (

X. Song

If one retains M^2/Q^2 terms in the kinematics, the Nachtmann variable ξseems to be more appropriate to describe deep inelastic lepton-nucleon scattering. Up to the first power of M^2/Q^2, a modified Wandzura-Wilczek relation with respect to ξwas derived. Kinematical correction factors are given as functions of ξand Q^2. A comparison of the modified g_2^WW(ξ

Charis Anastopoulos

In this paper we elaborate on the structure of the continuous-time histories description of quantum theory, which stems from the consistent histories scheme. In particular, we examine the construction of history Hilbert space, the identification of history observables and the form of the decoherence functional (the object that contains the probability inform

Sumit R. Das, Antal Jevicki, Samir D. Mathur

It has been recently suggested that gravitons moving in $AdS_m \times S^n$ spacetimes along the $S^n$ blow up into spherical $(n-2)$ branes whose radius increases with increasing angular momentum. This leads to an upper bound on the angular momentum, thus ``explaining&#39;&#39; the stringy exclusion principle. We show that this bound is present only for stat

J. W. Moffat

We study perturbative noncommutative quantum gravity by expanding the gravitational field about a fixed classical background. A calculation of the one loop gravitational self-energy graph reveals that only the non-planar graviton loops are damped by oscillating internal momentum dependent factors. The noncommutative quantum gravity perturbation theory is not

G. Fleming, J. Kogut, P. Vranas

The dynamical N=1, SU(2) Super Yang-Mills theory is studied on the lattice using a new lattice fermion regulator, domain wall fermions. This formulation even at non-zero lattice spacing does not require fine-tuning, has improved chiral properties and can produce topological zero-mode phenomena. Numerical simulations of the full theory on lattices with the to

Seif Randjbar-Daemi, Mikhail Shaposhnikov

We present new solutions of higher dimensional Einstein&#39;s equations with a cosmological constant that localize gravity on branes which are transverse to Ricci-flat manifolds or to homogeneous spaces with topologically non-trivial solutions of gauge field equations. These solutions are relevant for the localization of chiral fermions on a brane.

Gaston Giribet, Claudio Simeone

A global phase time is identified for homogeneous and isotropic cosmological models yielding from the low energy effective action of closed bosonic string theory. When the Hamiltonian constraint allows for the existence of an intrinsic time, the quantum transition amplitude is obtained by means of the usual path integral procedure for gauge systems.

David E. Rosenberg

There are multiple examples of gravitational losses in neutron stars and black holes. Protons and neutrons have been found to have enormous repulsive pressures that highly squeezed collapsing matter cannot overcome. The case against singularities follows. Galactic black hole gravitational losses can supply the missing dark energy. With highly squeezed nucleo

Simon Trebst, Anirvan Sengupta

We discuss magnetic excitations of a spin-cluster model which has been suggested to describe the low temperature phase of alpha&#39;-NaV_2O_5. This model fulfills all symmetry criteria proposed by recent x-ray investigations. We find that this model is not able to describe the occurence of two well separated magnon lines perpendicular to the ladder direction

Paul Fendley, Chetan Nayak

We consider the problem of tunneling between spinless 1D Luttinger liquid chains. We show how to map the problem onto the 4-state chiral clock model together with a free boson for the total charge mode. We use a variety of results, some of them exact, from the integrable chiral Potts model and the study of commensurate/incommensurate transitions to deduce th

I. L. Menezes-Sobrinho, J. G. Moreira, A. T. Bernardes

We study the existence of distinct failure regimes in a model for fracture in fibrous materials. We simulate a bundle of parallel fibers under uniaxial static load and observe two different failure regimes: a catastrophic and a slowly shredding. In the catastrophic regime the initial deformation produces a crack which percolates through the bundle. In the sl

G. F. Fiete, J. S. Hersch, E. J. Heller, H. C. Manoharan

We explain the origin of the Kondo mirage seen in recent quantum corral Scanning Tunneling Microscope (STM) experiments with a scattering theory of electrons on the surfaces of metals. Our theory combined with experimental data provides the first direct observation of a single Kondo atom phase shift. The Kondo mirage at the empty focus of an elliptical quant

L. Covi, D. H. Lyth

Best-fit values of the spectral index of the curvature perturbation are presented, assuming the $Λ$CDM cosmology. Apart from the spectral index, the parameters are the Hubble parameter, the total matter density and the baryon density. The data points are intended to represent all measurements which are likely to significantly affect the result. The cosmic mi

Hans Aschauer, Hans J. Briegel

We give a security proof of quantum cryptography based entirely on entanglement purification. Our proof applies to all possible attacks (individual and coherent). It implies the security of cryptographic keys distributed with the help of entanglement-based quantum repeaters. We prove the security of the obtained quantum channel which may not only be used for

Helmar Meier, Zlatko Halabuka, Kai Hencken, Dirk Trautmann

We study the bound-free electron-positron pair production in relativistic heavy ion collisions to different bound states in a full Plane Wave Born Approximation (PWBA) calculation. Exact Dirac wave functions are used for both the bound electron and the free positron in the final states. Results for the Relativistic Heavy Ion Collider RHIC as well as the fort

I. Wetzorke, F. Karsch

When applying the maximum entropy method (MEM) to the analysis of hadron correlation functions in QCD a central issue is to understand to what extent this method can distinguish bound states, resonances and continuum contributions to spectral functions. We discuss these issues by analyzing meson and diquark correlation functions at zero temperature as well a

K. G. Chetyrkin, T. Seidensticker

We present numerical results for the two loop QCD corrections to the ghost gluon vertex, the quark gluon vertex, and the triple gluon vertex in the massless limit at the symmetric point. We restrict ourselves to the tensor structures existing in the tree level. The corrections are used to examine different coupling constant definitions in momentum subtractio

V. Gurarie, A. Zee

We study the quantum Hall transition using the density-density correlation function. We show that in the limit h->0 the electron density moves along the percolating trajectories, undergoing normal diffusion. The localization exponent coincides with its percolation value ν=4/3. The framework provides a natural way to study the renormalization group flow from

W. Y. Hwang, H. J. Lee, D. Ahn, S. W. Hwang

We propose schemes that are efficient when each pair of qubits undergoes some imperfect collective decoherence with different baths. In the proposed scheme, each pair of qubits is first encoded in a decoherence-free subspace composed of two qubits. Leakage out of the encoding space generated by the imperfection is reduced by the quantum Zeno effect. Phase er

W. Y. Hwang, D. Ahn, S. W. Hwang

We show that errors are not generated correlatedly provided that quantum bits do not directly interact with (or couple to) each other. Generally, this no-qubits-interaction condition is assumed except for the case where two-qubit gate operation is being performed. In particular, the no-qubits-interaction condition is satisfied in the collective decoherence m

Jayita Chatterjee, Manidipa Mitra, A. N. Das

A two-site double exchange model with a single polaron is studied using a perturbation expansion based on the modified Lang-Firsov transformation. The antiferromagnetic to ferromagnetic transition and the crossover from small to large polaron are investigated for different values of the antiferromagnetic interaction ($J$) between the core spins and the hoppi

O. Juillet, S. Fleck, L. Theussl, J. -M. Richard

We derive a new lower bound for the ground state energy $E^{\rm F}(N,S)$ of N fermions with total spin S in terms of binding energies $E^{\rm F}(N-1,S \pm 1/2)$ of (N-1) fermions. Numerical examples are provided for some simple short-range or confining potentials.

D. P. Pritzkau, R. H. Siemann

Results are reported from an experiment on RF pulsed heating of copper at SLAC. Damage in the form of cracks may be induced on the surface after the application of many pulses of RF. The experiment consists of two circularly cylindrical cavities operated in the TE011 mode at a resonant frequency of 11.424 GHz. Each cavity received 8.5 MW, 1.2 microsecond pul

D. Douglas, S. V. Benson, G. A. Krafft, R. Li

An upgrade of the Jefferson Lab IR FEL is now under construction. It will provide 10 kW output light power in a wavelength range of 2-10 microns. The FEL will be driven by a modest-sized 80-210 MeV, 10 mA energy-recovering superconducting RF (SRF) linac. Stringent phase space requirements at the wiggler, low beam energy, and high beam current subject the des

C. L. Bohn, K. -Y. Ng

We recently developed an analytic theory of cumulative multibunch beam breakup that includes a linear variation of transverse focusing across the bunch train. The focusing variation saturates the exponential growth of the beam breakup and establishes an algebraic decay of the transverse bunch displacement versus bunch number. In this paper we illustrate how

J. C. Ribes, G. Delaunay, J. Delvaux, E. Merle

The AIRIX facility is a high current linear accelerator (2-3.5kA) used for flash-radiography at the CEA of Moronvilliers France. The general background of this study is the diagnosis and the predictive maintenance of AIRIX. We will present a tool for fault diagnosis and monitoring based on pattern recognition using artificial neural network. Parameters extra

E. Allahyarov, H. Löwen

Using computer simulations of two charged colloidal spheres with their counterions in a hard sphere solvent, we show that the granular nature of the solvent significantly influences the effective colloidal interaction. For divalent counterions, the total effective force can become attractive generated by counterion hydration, while for monovalent counterions

C. Henkel, K. Joulain, R. Carminati, J. -J. Greffet

We analyze the spatial coherence of the electromagnetic field emitted by a half-space at temperature T close to the interface. An asymptotic analysis allows to identify three different contributions to the cross-spectral density tensor in the near-field regime. It is shown that the coherence length can be either much larger or much shorter than the wavelengt

A. M. Selvam

Recent studies indicate a close association between the distribution of prime numbers and quantum mechanical laws governing the subatomic dynamics of quantum systems such as the electron or the photon. Number theoretical concepts are intrinsically related to the quantitative description of dynamical systems of all scales ranging from the microscopic subatomi

S. Liran, A. Marinov, N. Zeldes

A semiempirical shell model mass equation based on magic number Z=126 and applicable to translead elements with N smaller or equal to 126 is presented. For alpha decay energies the equation is shown to have a high predictive power and an rms deviation from the data of about 100 keV. The rms deviations for masses and other mass differences are between about 2

Yoshitaka Iwasaki, Hiroaki Kouno, Akira Hasegawa, Masahiro Nakano

A relation among the effective nucleon mass $M^*$, the incompressibility $K$ and the effective $σ$-meson mass $m_{\rm s}^*$ in nuclear matter is studied by using the relativistic nuclear model. We found that there is a strong correlation between $M^*$ and $m_{\rm s}^*$, while there is only a weak correlation between $K$ and $m_{\rm s}^*$. At the normal densi

K. Saito, C. Boros, K. Tsushima, F. Bissey

We study deep inelastic scattering on isospin asymmetric nuclei. In particular, the difference of the nuclear structure functions and the Gottfried sum rule for the lightest mirror nuclei, 3He and 3H, are investigated. It is found that such systems can provide significant information on charge symmetry breaking and flavor asymmetry in the nuclear medium. Fur

Kevin Hall, David J. Christini

Dynamical control of biological systems is often restricted by the practical constraint of unidirectional parameter perturbations. We show that such a restriction introduces surprising complexity to the stability of one-dimensional map systems and can actually improve controllability. We present experimental cardiac control results that support these analyse

T. Kojima

Finite XXZ chain with double boundaries is considered at critical regime $-1<Δ<1$. We construct the eigenvectors of finite Hamiltonian by means of vertex operators and the quasi-boundary states. Using the free field realizations of the vertex operators and the quasi-boundary states, integral representations for the correlation functions are derived.

Shin-itiro Goto, Kazuhiro Nozaki

By means of the perturbative renormalization group method, we study a long-time behaviour of some symplectic discrete maps near elliptic and hyperbolic fixed points. It is shown that a naive renormalization group (RG) map breaks the symplectic symmetry and fails to describe a long-time behaviour. In order to preserve the symplectic symmetry, we present a reg