April 2002 arXiv papers — page 14

Hyung Do Kim, Jihn E. Kim, Hyun Min Lee

A possibility of 5D gauge unification of $SU(2)_L \times U(1)_Y$ in $SU(3)_W$ is examined. The orbifold compactification allows fixed points where $SU(2)_L\times U(1)_Y$ representations can be assigned. We present a few possibilities which give long proton lifetime, top-bottom mass hierarchy from geometry, and reasonable neutrino masses. In general, these {\

John N. Bahcall, M. C. Gonzalez-Garcia, C. Pena-Garay

The 8B solar neutrino flux inferred from a global analysis of solar neutrino experiments is within 11% (1 sigma) of the predicted standard solar model value if only active neutrinos exist, but could be as large as 1.7 times the standard prediction if sterile neutrinos exist. We show that the total 8B neutrino flux (active plus sterile neutrinos) can be deter

A. Zhuk

We consider dilatonic brane-world models with a non-minimal coupling between a dilaton and usual matter on a brane. We demonstrate that variation of the fundamental constants on the brane due to such interaction leads to strong restrictions on parameters of models. In particular, the experimental bounds on variation of the fine structure constant rule out no

R. Sekhar Chivukula, Nick Evans, Elizabeth H. Simmons

Recently a new class of composite Higgs models have been developed which give rise to naturally light Higgs bosons without supersymmetry. Based on the chiral symmetries of ``theory space,'' involving replicated gauge groups and appropriate gauge symmetry breaking patterns, these models allow the scale of the underlying strong dynamics giving rise to

M. Aguado, M. Asorey

We prove the analyticity of the finite volume QCD partition function for complex values of the theta-vacuum parameter. The absence of singularities different from Lee-Yang zeros only permits ^ cusp singularities in the vacuum energy density and never v cusps. This fact together with the Vafa-Witten diamagnetic inequality implies the vanishing of the density

Géza Giedke, J. Ignacio Cirac

We characterize the class of all physical operations that transform Gaussian states to Gaussian states. We show that this class coincides with that of all operations which can be performed on Gaussian states using linear optical elements and homodyne measurements. For bipartite systems we characterize the processes which can be implemented by local operation

Stefano Giovanazzi, Axel Gorlitz, Tilman Pfau

We have studied the tunability of the interaction between permanent dipoles in Bose-Einstein condensates. Based on time-dependent control of the anisotropy of the dipolar interaction, we show that even the very weak magnetic dipole coupling in alkali gases can be used to excite collective modes. Furthermore, we discuss how the effective dipolar coupling in a

Tianjun Li, Tao Liu

We deconstruct the non-supersymmetric SU(5) breaking by discrete symmetry on the space-time $M^4\times S^1$ and $M^4\times S^1/(Z_2\times Z_2')$ in the Higgs mechanism deconstruction scenario. And we explain the subtle point on how to exactly match the continuum results with the latticized results on the quotient space $S^1/Z_2$ and $S^1/(Z_2\times Z_2&#

Theja N. De Silva, Michael Ma, Fu Chun Zhang

We have re-analyze the Schwinger boson mean field theory (SBMFT) for Heisenberg spin models on the cubic lattice. We find that the second order phase transition point for magnetic ordering previously reported corresponds to a local maximum of the free energy functional. For both ferromagnetic and antiferromagnetic Heisenberg models with spin $S \geq S_C$, wh

Philip C. Argyres, R. Maimon, Sophie Pelland

We solve for the effective actions on the Coulomb branches of a class of N=2 supersymmetric theories by finding the complex structure of an M5 brane in an appropriate background hyperkahler geometry corresponding to the lift of two O6^- orientifolds and four D6 branes to M theory. The resulting Seiberg-Witten curves are of finite genus, unlike other solution

V. M. Braun, D. Yu. Ivanov, A. Schafer, L. Szymanowski

We carry out a detailed calculation of the cross section of pion diffraction dissociation into two jets with large transverse momenta, originating from a hard gluon exchange between the pion constituents. Both the quark and the gluon contribution are considered and in the latter case we present calculations both in covariant and in axial gauges. We find that

Alejandro Corichi, Jeronimo Cortez, Hernando Quevedo

A non-perturbative canonical quantization of Gowdy $T^3$ polarized models carried out recently is considered. This approach profits from the equivalence between the symmetry reduced model and 2+1 gravity coupled to a massless real scalar field. The system is partially gauge fixed and a choice of internal time is performed, for which the true degrees of freed

Randall K. Smith, Richard J. Edgar, Richard A. Shafer

We present observations of the X-ray halo around the LMXB GX 13+1 from the Chandra X-ray telescope. The halo is caused by scattering in interstellar dust grains, and we use it to diagnose the line-of-sight position, size distribution, and density of the grains. Using the intrinsic energy resolution of Chandra's ACIS CCDs and the recent calibration observ

Andrea Crisanti, Luca Leuzzi

We study the mean-field static solution of the Blume-Emery-Griffiths-Capel model with quenched disorder, an Ising-spin lattice gas with quenched random magnetic interaction. The thermodynamics is worked out in the Full Replica Symmetry Breaking scheme. The model exhibits a high temperature/low density paramagnetic phase. When the temperature is decreased or

F. C. Lombardo, F. D. Mazzitelli, R. J. Rivers

We study the onset of a classical order parameter after a second-order phase transition in quantum field theory. We consider a quantum scalar field theory in which the system-field (long-wavelength modes), interacts with its environment, represented both by a set of scalar fields and by its own short-wavelength modes. We compute the decoherence times for the

E. A. Korsunsky, M. Fleischhauer

We derive analytic solution for pulsed frequency conversion based on electromagnetically induced transparency (EIT) or maximum coherence in resonant atomic vapors. In particular drive-field and coherence depletion are taken into account. The solutions are obtained with the help of an Hamiltonian approach which in the adiabatic limit allows to reduce the full

S. Trillo, C. Conti, P. Di Trapani, O. Jedrkiewicz

We predict that the combination of space and time modulational instabilities occuring via parametric wave-mixing in quadratic media leads to coloured conical emission. This phenomenon should be observed under conditions usually employed in second-harmonic generation experiments.

Luigi Del Debbio, Haralambos Panagopoulos, Ettore Vicari

We study the $θ$ dependence of four-dimensional SU($N$) gauge theories, for $N\geq 3$ and in the large-N limit. We use numerical simulations of the Wilson lattice formulation of gauge theories to compute the first few terms of the expansion of the ground-state energy $F(θ)$ around $θ=0$, $F(θ)-F(0) = A_2 θ^2 (1 + b_2 θ^2 + ...)$. Our results support Witten&#

Chun-Khiang Chua, Wei-Shu Hou, Shang-Yuu Tsai

Motivated by recent data on B-> p pbar K decay, we study various charmless three-body baryonic B decay modes, including Lambda pbar pi, Sigma0 pbar pi, p pbar pi, p pbar Kbar0, in a factorization approach. These modes have rates of order 10^{-6}. There are two mechanisms for the baryon pair production, current-produced and transition. The behavior of decay s

S. E. Derkachov, G. P. Korchemsky, J. Kotanski, A. N. Manashov

We present a complete description of the spectrum of compound states of reggeized gluons in QCD in multi-colour limit. The analysis is based on the identification of these states as ground states of noncompact Heisenberg SL(2,C) spin magnet. A unique feature of the magnet, leading to many unusual properties of its spectrum, is that the quantum space is infin

Ian D. Lawrie

The possibility of a friction term in the equation of motion for a scalar field is investigated in non-equilibrium field theory. The results obtained differ greatly from existing estimates based on linear response theory, and suggest that dissipation is not well represented by a term of the form $η\dotϕ$.

S. Valverde, R. Ferrer i Cancho, R. V. Sole

A large number of complex networks, both natural and artificial, share the presence of highly heterogeneous, scale-free degree distributions. A few mechanisms for the emergence of such patterns have been suggested, optimization not being one of them. In this letter we present the first evidence for the emergence of scaling (and smallworldness) in software ar

Alexander A. Osipov, Brigitte Hiller

The 't Hooft six quark flavor mixing interaction (N_f=3) is bosonized by the path integral method. The considered complete Lagrangian is constructed on the basis of the combined 't Hooft and U(3)X U(3) extended chiral four fermion Nambu-Jona-Lasinio interactions. The method of the steepest descents is used to derive the effective mesonic Lagrangian.

S. Peris

I review some progress made on the problem of calculating electroweak processes of mesons at low energy with the use of an approximation to large-Nc QCD which we call the Minimal Hadronic Approximation. An update of results for the matrix elements of the electroweak penguin operators Q7 and Q8 is also given.

Vladimir Pestov

We discuss some techniques related to equivariant compactifications of uniform spaces and amenability of topological groups. In particular, we give a new proof of a recent result by Glasner and Weiss describing the universal minimal flow of the infinite symmetric group ${\mathfrak S}_\infty$ with the standard Polish topology, and extend Bekka's concept o

M. Duetsch, K. -H. Rehren

In the perturbative AdS-CFT correspondence, the dual field whose source are the prescribed boundary values of a bulk field in the functional integral, and the boundary limit of the quantized bulk field are the same thing. This statement is due to the fact that Witten graphs are boundary limits of the corresponding Feynman graphs for the bulk fields, and henc

A. P. Kostyuk, M. I. Gorenstein, H. Stoecker, W. Greiner

The dependence of the J/psi yield on the transverse energy E_T in heavy ion collisions is considered within the statistical c anti-c coalescence model. The model fits the NA50 data for Pb+Pb collisions at the CERN SPS even in the high-E_T region (E_T > 100 GeV). Here E_T-fluctuations and E_T-losses in the dimuon event sample naturally create the celebrated d

I. Montvay

The numerical simulation of domain wall quarks with the two-step multi-boson (TSMB) algorithm is considered. The inclusion of single quark flavours, as required for strange quarks, is discussed. The usage of computer memory can be kept relatively low, independently of the order of polynomial approximations. Tests are performed with two flavours (N_f=2) of de

Christian Baer, Mattias Dahl

We introduce a differential topological invariant for compact differentiable manifolds by counting the small eigenvalues of the Conformal Laplace operator. This invariant vanishes if and only if the manifold has a metric of positive scalar curvature. We show that the invariant does not increase under surgery of codimension at least three and we give lower an

Hidetsugu Sakaguchi

Deterministic diffusion in temporally oscillating convection is studied for particles with finite mass. The particles are assumed to obey a simple dissipative dynamical system and the particle diffusion is induced by the strange attractor. The diffusion constants are numerically calculated for convection models with free and rigid boundary conditions.

Tomonori Totani, Alin Panaitescu

We make a quantitative prediction for the detection rate of orphan GRB afterglows as a function of flux sensitivity in X-ray, optical, and radio wavebands, based on a recent model of collimated GRB afterglows. We find that the orphan afterglow rate strongly depends on the opening angle of the jet (roughly \propto θ_jet^{-2}), as expected from simple geometri

Sumiyoshi Abe, Norikazu Suzuki

The cumulative probability distribution of sparseness time interval in the Internet is studied by the method of data analysis. Round-trip time between a local host and a destination host through ten odd routers is measured using the Ping Command, i.e., doing echo experiment. It is found that the data are well described by the q-exponential destributions, whi

Tohya Hiroshima

An asymptotic entanglement measure for any bipartite states is derived in the light of the dense coding capacity optimized with respect to local quantum operations and classical communications. General properties and some examples with explicit forms of this entanglement measure are investigated.

D. K. Park, Hungsoo Kim

The graviton localized on the 3-brane is examined in Randall-Sundrum brane-world scenario from the viewpoint of one-dimensional singular quantum mechanics. For the Randall-Sundrum single brane scenario the one-parameter family of the fixed-energy amplitude is explicitly computed where the free parameter $ξ$ parametrizes the various boundary conditions at the

Mateusz Ruszkowski, Mitchell C. Begelman

Radiation dominated accretion disks are likely to be subject to the ``photon bubble'' instability, which may lead to strong density inhomogeneities on scales much shorter than the disk scale height. Such disks -- and magnetized, radiation-dominated atmospheres in general -- could radiate well above the Eddington limit without being disrupted. When de

L. A. Errico, G. Fabricius, M. Rentería, P. de la Presa

We present an ab initio study of the relaxations introduced in TiO2 when a Cd impurity substitutes a Ti atom and the experimental test of this calculation by a perturbed-angular-correlation (PAC) measurement of the orientation of the electric-field gradient (EFG) tensor at the Cd site. The ab-initio calculation predicts strong anisotropic relaxations of the

Ludovico Lanz, Bassano Vacchini

An approach to the description of subdynamics inside non-relativistic quantum field theory is presented, in which the notions of relevant observable, time scale and complete positivity of the time evolution are stressed. A scattering theory derivation of the subdynamics of a microsystem interacting through collisions with a macrosystem is given, leading to a

Günter Nimtz

Photonic tunneling permits superluminal signal transmission. The principle of causality is not violated but the time duration between cause and effect can be shortened compared with an interaction exchange with velocity of light. This outstanding property can be applied to speed-up photonic signal modulation and transmission as well as to improve micro-elect

V. S. Zapasskii, E. B. Alexandrov

It is shown that the direct Fourier synthesization of light beams allows one to create polarity-asymmetric waves, which are able, in the process of nonlinear interaction with a medium, to break its inversion symmetry. As a result, these "polar" waves may show the effect of optical rectification in nonlinear centrosymmetric media by generating light-i

Yu. V. Eremeichenkova, L. S. Metlov, A. F. Morozov

The coefficients of interatomic potential of simple form Exp-6 for neon are obtained. Repulsive part is calculated ab-initio in the Hartree-Fock approximation using the basis of atomic orbitals orthogonalized exactly on different lattice sites. Attractive part is determined empirically using single fitting parameter. The potential obtained describes well the

Mario Goto

We show that the locally constant force necessary to get a stable hyperbolic motion regime for classical charged particles, actually, is a subtle combination of an applied external force and the radiation reaction force. It suggests, as the Equivalence Principle is valid, that the gravitational mass of charged particle should be slight greater than its inert

A. Schiller, M. Guttormsen, M. Hjorth-Jensen, J. Rekstad

A model is developed which allows the investigation and classification of the pairing phase transition in atomic nuclei. The regions of the parameter space are discussed for which a pairing phase transition can be observed. The model parameters include: number of particles, attenuation of pairing correlations with increasing seniority, single particle level

A. Ramos, E. Oset, C. Bennhold

Using a unitary extension of chiral perturbation theory with a lowest-order s-wave SU(3) chiral Lagrangian we study low-energy meson-baryon scattering in the strangeness $S=-2$ sector. A scattering-matrix pole is found around 1606 MeV which corresponds to an s-wave $Ξ$ resonance with $J^P=1/2^-$. We identify this resonance with the $Ξ(1620)$ state, quoted in

Flavio H Fenton, Elizabeth M Cherry, Harold M. Hastings, Steven J. Evans

It has become widely accepted that the most dangerous cardiac arrhythmias are due to re- entrant waves, i.e., electrical wave(s) that re-circulate repeatedly throughout the tissue at a higher frequency than the waves produced by the heart's natural pacemaker (sinoatrial node). However, the complicated structure of cardiac tissue, as well as the complex i

K. Weibert, J. Main, G. Wunner

Classical chaotic systems with symbolic dynamics but strong pruning present a particular challenge for the application of semiclassical quantization methods. In the present study we show that the technique of periodic orbit quantization by harmonic inversion of trace formulae, which does not rely on the existence of a complete symbolic dynamics or other spec

Marc Toussaint, Christian Igel

Self-adaptation is used in all main paradigms of evolutionary computation to increase efficiency. We claim that the basis of self-adaptation is the use of neutrality. In the absence of external control neutrality allows a variation of the search distribution without the risk of fitness loss.

P. P. Kulish, N. Manojlovic

The problems connected with Gaudin models are reviewed by analyzing model related to the trigonometric osp(1|2) classical r-matrix. The eigenvectors of the trigonometric osp(1|2) Gaudin Hamiltonians are found using explicitly constructed creation operators. The commutation relations between the creation operators and the generators of the trigonometric loop

Runliang Lin, Wen-Xiu Ma, Yunbo Zeng

A method for introducing the higher order terms in the potential expansion to study the continuous limits of the Toda hierarchy is proposed in this paper. The method ensures that the higher order terms are differential polynomials of the lower ones and can be continued to be performed indefinitly. By introducing the higher order terms, the fewer equations in

H. Sakaguchi

A shock-like structure appears in a time-averaged pattern produced by the Kuramoto-Sivashinsky equation and the noisy Burgers equation with fixed boundary conditions. We show that the effective viscosity computed from the width of the time-averaged shock structure is consistent with that computed from the time correlation of the fluctuations. The effective v

R. Cartas-Fuentevilla

Expressions for the general and complete perturbations in terms of Debye potentials of static charged black holes in string theory, valid for curvature below the Planck scale, are derived starting from a decoupled set of equations and using Wald's method of adjoint operators. Our results cover both extremal and nonextremal black holes and are valid for a

R. Cartas-Fuentevilla

We present a new approach for constructing covariant symplectic structures for geometrical theories, based on the concept of adjoint operators. Such geometric structures emerge by direct exterior derivation of underlying symplectic potentials. Differences and similarities with other approaches and future applications are discussed.

Yu. P. Virchenko, Yu. A. Tolmacheva

The more exact upper estimate of the percolation threshold for the {\it site problem} on the quadratic lattice ${\Bbb Z}^2$ have been found on the basis of the cluster decomposition. It is done by the number estimate of cycles on ${\Bbb Z}^2$ which maybe external boundaries of finite clusters

C. Sparber, J. A. Carrillo, J. Dolbeault, P. A. Markowich

We analyze the long time behavior of transport equations for a class of dissipative quantum systems with Fokker-planck type scattering operator, subject to confining potentials of harmonic oscillator type. We establish the conditions under which there exists a thermal equilibrium state and prove exponential decay towards it, using (classical) entropy-methods

Joseph M. Landsberg, Laurent Manivel

We study the projective geometry of homogeneous varieties $X= G/P\subset P(V)$, where $G$ is a complex simple Lie group, $P$ is a maximal parabolic subgroup and $V$ is the minimal $G$-module associated to $P$. Our study began with the observation that Freudenthal's magic chart could be derived from Zak's theorem on Severi varieties and standard geome

W. A. Zúñiga-Galindo

In this paper we present a polynomial time algorithm to compute the local zeta function Z(s,f) attached to a polynomial f(x) in Z[x] (in one variable, with splitting field Q) and a prime p. The algorithm reduces in polynomial time the computation of Z(s,f) to the computation of a factorization of f(x) over Q. This reduction is accomplished by constructing a

Stefano Vidussi

The aim of this paper is to discuss some applications of the relation between Seiberg-Witten theory and two natural norms defined on the first cohomology group of a closed 3-manifold N - the Alexander and Thurston norms. We start by giving a "new" proof of McMullen's inequality between these norms, and then use these norms to study two problems r

Cristian D. Gonzalez-Aviles

Let $G$ be an abelian group of order $n$ and let $R$ be a commutative ring which admits a homomorphism ${\Bbb Z}[ζ_{n}]\ra R$, where $ζ_{n}$ is a (complex) primitive $n$-th root of unity. Given a finite $R[G\e]$-module $M$, we derive a formula relating the order of $M$ to the product of the orders of the various isotypic components $M^{\eχ}$ of $M$, where $χ

Rui Pedro Carpentier

In [2] Kauffman and Vogel constructed a rigid vertex regular isotopy invariant for unoriented four-valent graphs embedded in three dimensional space. It assigns to each embedded graph G a polynomial, denoted [G], in three variables, A, B and a, satisfying three skein relations, and is defined in terms of a state-sum and the Dubrovnik polynomial for links. In

Moulay-Tahar Benameur, Victor Nistor

We study the Hochschild homology groups of the algebra of complete symbols on a foliated manifold $(M,F)$. The first step is to relate these groups to the Poisson homology of $(M,F)$ and of other related foliated manifolds. We then establish several general properties of the Poisson homology groups of foliated manifolds. As an example, we completely determin

Frank Hansen, Guoxing Ji, Jun Tomiyama

We prove the existence of gaps between all the different classes of matrix monotone functions defined on an interval, provided the interval is non trivial and different from the whole real line. We then show how matrix monotone functions may be used in the characterization of certain C*-algebras as an alternative to the study of the matricial structure by po

Oana Dragulete, Liviu Ornea, T. S. Ratiu

We extend the theorems concerning the equivariant symplectic reduction of the cotangent bundle to contact geometry. The role of the cotangent bundle is taken by the cosphere bundle. We use Albert's method for reduction at zero and Willett's method for non-zero reduction. We provide examples for both cases.

David E. Barrett, Sophia Vassiliadou

We obtain an asymptotic expansion and some regularity results for the Bergman kernel on the intersection of two balls in C^2.

Ken McMurdy

This paper continues the study of certain two-dimensional Galois representations attached to modular forms (mod p) via a construction due to Deligne. In particular, we prove a criterion for determining when the representation is split when restricted to a decomposition group at p.While this problem was already well understood for "nonexceptional" mod

R. Cartas-Fuentevilla

It is proved that the projections of the deformation vector field, normal and tangential to the worldsheet manifold swept out by Dirac-Nambu-Goto bosonic extendons propagating in a curved background, play the role of {\it global} symplectic potentials on the corresponding Witten covariant phase space. It is also proved that the {\it presymplectic} structure

R. Cartas-Fuentevilla

On the basis of the covariant description of the canonical formalism for quantization, we present the basic elements of the symplectic geometry for a restricted class of topological defects propagating on a curved background spacetime. We discuss the future extensions of the present results.

R. Cartas-Fuentevilla

Using a fully covariant formalism given by Carter for the deformation dynamics of p-branes governed by the Dirac-Nambu-Goto action in a curved background, it is proved that the corresponding Witten's phase space is endowed with a covariant symplectic structure, which can serve as a starting point for a phase space quantization of such objects. Some open

Richard Easther, Brian R. Greene, William H. Kinney, Gary Shiu

We derive a general expression for the power spectra of scalar and tensor fluctuations generated during inflation given an arbitrary choice of boundary condition for the mode function at a short distance. We assume that the boundary condition is specified at a short-distance cutoff at a scale $M$ which is independent of time. Using a particular prescription

E. Prodan

The two parameter model is reduced to a one parameter model by using simple transformations. Because the separation between different phase regions for a one parameter model is just a point, the equivalence between the two models leads to the exact equation of the line that separates the broken and un-broken phases in the $(λ,σ)$ plane. Also, we obtain nontr

Stanley J. Brodsky

The advent of back-scattered laser beams for electron-positron colliders will allow detailed studies of a large array of high energy photon-photon and photon-electron collision processes with polarized beams. These include tests of electroweak theory in photon-photon annihilation such as $γγ\to W^+ W^-$, $γγ\to $ Higgs bosons, and higher-order loop processes

John Ellis, Keith A. Olive, Yudi Santoso

Without assuming that Higgs masses have the same values as other scalar masses at the input GUT scale, we combine constraints on the minimal supersymmetric extension of the Standard Model (MSSM) coming from the cold dark matter density with the limits from direct searches at accelerators such as LEP, indirect measurements such as b to s gamma decay and the a

G. C. Branco, T. Morozumi, B. M. Nobre, M. N. Rebelo

We discuss the possibility of relating the size and sign of the observed baryon asymmetry of the universe to CP violation observable at low energies, in a framework where the observed baryon asymmetry is produced by leptogenesis through out of equilibrium decay of heavy Majorana neutrinos. We have shown that although in general such a connection cannot be es

M. Ambrosio

The MACRO underground detector at Gran Sasso Laboratory recorded 60 million secondary cosmic ray muons from February 1989 until December 2000. Different techniques were used to analyze this sample in search for density excesses from astrophysical point-like sources. No evidence for DC excesses for any source in an all-sky survey is reported. In addition, sea

R. Arnowitt, B. Dutta

We examine supergravity models with grand unification at M_G possessing R parity invariance. Current data has begun to significantly constrain the parameter space. Thus for mSUGRA, accelerator data places a lower bound on m_{1/2} of m_{1/2} >~300 GeV while astronomical data on the amount of relic dark matter narrowly determines m_0 in terms of m_{1/2} (for f

Chun-Khiang Chua, Wei-Shu Hou, Shang-Yuu Tsai

Recent data on B->p pbar K, K0 pi pi and K Kbar K hint at a $\sim 2.3$ GeV object recoiling against a kaon. This could be the narrow state observed in J/ψ-> gamma xi. Nonobservation in p pbar annihilation implies ${\cal B}(ξ\to p\bar p) \sim$ few $\times 10^{-3}$, consistent with eta_c and J/ψdecays, but there are actual hints in p pbar -> phi phi and p p->

Guido Altarelli

1. Introduction 2. Massless QCD and Scale Invariance 3. The Renormalisation Group and Asymptotic Freedom 4. More on the Running Coupling 5. Application to Hard Processes 5.1 $R_{e^+e^-}$ and Related Processes 5.2 The Final State in $e^+e^-$ Annihilation 5.3 Deep Inelastic Scattering 5.4 Factorisation and the QCD Improved Parton Model 6. Measurements of $α_s$

M. Oettel, R. Alkofer

In treating the relativistic three-quark problem, a dressed-quark propagator parameterization is used which is compatible with recent lattice data and pion observables. Furthermore two-quark correlations are modeled as a series of quark loops in the scalar and axialvector channel. The resulting reduced Faddeev equations are solved for nucleon and delta. Nucl

Katsumasa Ikematsu, Keisuke Fujii, Zenro Hioki, Yukinari Sumino

We developed a new method for full kinematical reconstruction of the ttbar system near its threshold at future linear e+e- colliders. In the core of the method lies likelihood fitting which is designed to improve measurement accuracies of the kinematical variables that specify the final states resulting from ttbar decays. The improvement is demonstrated by a

R. Cartas-Fuentevilla

Local continuity equations involving background fields and variantions of the fields, are obtained for a restricted class of solutions of the Einstein-Maxwell and Einstein-Weyl theories using a new approach based on the concept of the adjoint of a differential operator. Such covariant conservation laws are generated by means of decoupled equations and their

R. Cartas-Fuentevilla

We present a new approach for finding conservation laws in the perturbation theory of black holes which applies for the more general cases of non-Hermitian equations governing the perturbations. The approach is based on a general result which establishes that a covariantly conserved current can be obtained from a solution of any system of homogeneous linear

Roberto A. Sussman, Mustapha Ishak

We consider a generalization of the Lemaitre-Tolman-Bondi (LTB) solutions by keeping the LTB metric but replacing its dust matter source by an imperfect fluid with anisotropic pressure $Π_{ab} $. Assuming that total matter-energy density $ρ$ is the sum of a rest mass term, $\rhom$, plus a radiation $\rhor=3p$ density where $p$ is the isotropic pressure, Eins

Jerzy Lewak

The theoretical foundations of a new model and paradigm (called TIE) for data storage and access are introduced. Associations between data elements are stored in a single Matrix table, which is usually kept entirely in RAM for quick access. The model ties together a very intuitive "guided" GUI to the Matrix structure, allowing extremely easy complex

Rajiv C. Shah, Jay P. Kesan

Communication technologies contain embedded values that affect our society's fundamental values, such as privacy, freedom of speech, and the protection of intellectual property. Researchers have shown the design of technologies is not autonomous but shaped by conflicting social groups. Consequently, communication technologies contain different values whe

A. S. Martins, J. G. Menchero, R. B. Capaz, Belita Koiller

The wave function and binding energy for shallow donors in GaAs are calculated within the tight binding (TB) approach, for supercells containing up to two million atoms. The resulting solutions, coupled with a scaling law, allow extrapolation to the bulk limit. A sharp shallow-deep transition is obtained as the impurity perturbation increases. The model allo

Jan Martinek, Józef Barnas, Sadamichi Maekawa, Herbert Schoeller

We propose a new method of direct detection of spin accumulation, which overcomes problems of previous measurement schemes. A spin dependent current in a single-electron transistor with ferromagnetic electrodes leads to spin accumulation on the metallic island. The resulting spin-splitting of the electrochemical potentials of the island, because of an additi

Gang Lu, Efthimios Kaxiras

The interaction of vacancy with dislocations in Al is studied using the Semidiscrete Variational Peierls-Nabarro model with ab initio determined gamma surface. For the first time, we confirm theoretically the so-called vacancy lubrication effect on dislocation motion in Al, a discovery that can settle a long-standing controversy in dislocation theory for fcc

K. Storr, D. Graf, J. S. Brooks, L. Balicas

We report inter-plane ($R_{zz}$) electrical transport measurements in the \tp series of organic conductors at very high magnetic fields. In the field range between 36 and 60 T $R_{zz}$ shows a very hysteretic first order phase transition from metallic to an insulating state. This transition does not affect the Shubnikov-de-Haas oscillations associated with t

C. Enss, S. Ludwig

Recently, it has been discovered that in contrast to expectations the low-temperature dielectric properties of some multi-component glasses depend strongly on magnetic fields. In particular, the low-frequency dielectric susceptibility and the amplitude of coherent polarization echoes show striking non-monotonic magnetic field dependencies. The low-temperatur

D. La-Orauttapong, J. Toulouse, Z. -G. Ye, R. Erwin

Diffuse neutron scattering is a valuable tool to obtain information about the size and orientation of the polar nanoregions that are a characteristic feature of relaxor ferroelectrics. In this paper, we present new diffuse scattering results obtained on Pb(Zn1/3Nb2/3)O3 (PZN for short) and (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3(PZN-xPT)single crystals (with x=4.5 and

Roberto da Silva, Nelson A. Alves, J. R. Drugowich de Felicio

In this paper we study the short-time behavior of the Blume-Capel model at the tricritical point as well as along the second order critical line. Dynamic and static exponents are estimated by exploring scaling relations for the magnetization and its moments at early stage of the dynamic evolution. Our estimates for the dynamic exponents, at the tricritical p

C. Bourbonnais

We briefly review the physics of electronic phases in low dimensional conductors. We begin by introducing the properties of the one-dimensional electron gas model using bosonization and renormalization group methods.We then tackle the influence of interchain coupling and go through the different instabilities of the electron system to the formation of higher

Yoshihiko Takano, Takeshi Hatano, Akihiro Fukuyo, Akira Ishii

A Bi2Sr2CaCu2O8+d cross-whiskers junction has been successfully discovered as a novel intrinsic Josephson junction without using any technique for micro-fabrication. Two Bi2Sr2CaCu2O8+d whisker crystals were placed crosswise on a MgO substrate and heated at 850C for 30 min. They were electrically connected at their c-planes. The measurement terminals were ma

Andreas Engel, H. J. Trodahl

Linear resistances and $IV$-characteristics have been measured over a wide range in the parameter space of the mixed phase of multilayered a-TaGe/Ge films. Three films with varying interlayer coupling and correlated defects oriented at an angle $\approx 25$ from the film normal were investigated. Experimental data were analyzed within vortex glass models and

I. Felner, U. Asaf

CaRuO3 is a perovskite with an orthorhombic distortion and shows the characteristics of spin-glass behavior below TC=87 K. The La3+ substitution for Ca2+ in Ca1-xLaxRuO3 samples, induces a disorder in the Ca site (the A site) and the system becomes antiferromagnetically (AFM) ordered with TN = 58 and 19 K for x=0.1 x=0.5 respectively. In the Ca1-xSrxRuO3 sys

M. Blaauboer

We derive a general scattering-matrix formula for the pumped current through a mesoscopic region attached to a normal and a superconducting lead. As applications of this result we calculate the current pumped through (i) a pump in a wire, (ii) a quantum dot in the Coulomb blockade regime, and (iii) a ballistic double-barrier junction, all coupled to a superc

D. Mihailovic

The experimental and theoretical challenges posed by the study of dynamically inhomogeneous systems are outlined in the context of cuprates and other oxides. Considering the pitfalls in the single-component approach to the analysis of inhomogeneous systems, the effect of either temporal or spatial averaging by different experiments is discussed. A group-theo

B. Jancovici

After a brief review of previous work, two exactly solvable two-dimensional models of a finite Coulomb fluid in a disc are studied. The charge correlation function near the boundary circle is computed. When the disc radius is large compared to the bulk correlation length, a correlation function of the surface charge density can be defined. It is checked, on

J. Friedel, M. Kohmoto

Recent results on electrons and holes doped CuO 2 planes confirm the marked covalency of CuO bonding, suggesting a band picture of long and short range antiferromagnetism. The maxima of superconductive T c versus doping can be related to the crossing by the Fermi level of the edges of the pseudogap due to antiferromagnetic short range order (bonding edge for

E. V. Vasiliu

Based on the many-body theory of metals in the third order of the perturbation expansion in electron-ion interaction pseudopotential, the potentials of pair and three-ion interactions are calculated in liquid lead, aluminium and beryllium at their melting temperatures. The reducible and irreducible three-ion interactions have an attractive nature on distance

Paulo Murilo Castro de Oliveira

The purpose of this text is: 1) to clarify the foundations of the broad histogram method, stressing the conceptual differences between it and reweighting procedures in general; 2) to propose a very simple microcanonical dynamic rule, yet to be tested by theoretical grounds, which could provide a good improvement to numerical simulations.

K. Ishikawa, N. Maeda

Physical properties of anisotropic compressible quantum Hall states and their implications to integer quantum Hall effect are studied based on a mean field theory on the von Neumann lattice. It is found that the Hall gas has unusual thermodynamic properties such as negative pressure and negative compressibility and unusual transport properties. Transport pro