March 2004 arXiv papers — page 4

L. V. Panina, S. I. Sandacci, D. P. Makhnovskiy

The effect of tensile stress on magnetoimpedance (MI) in CoMnSiB amorphous wires at microwave frequencies (0.5-3 GHz) is investigated both experimentally and theoretically. In the presence of the dc bias magnetic field of the order of the anisotropy field, the impedance shows very large and sensitive change when the wire is subjected to a tensile stress: 100

Jorge Quintanilla, Vivaldo L. Campo

We study a simple model of conducting polymers in which a single electron propagates through a randomly tangled chain. The model has the geometry of a small-world network, with a small density $p$ of crossings of the chain acting as shortcuts for the electron. We use numerical diagonalisation and simple analytical arguments to discuss the density of states,

Paul Crowther, Lucy Hadfield, Hans Schild, Werner Schmutz

We have surveyed the metal-rich spiral galaxy M83 (NGC5236) for its Wolf-Rayet population using VLT-FORS2 narrow-band imaging and follow-up spectroscopy. From a total of 280 candidates identified using HeII 4686 imaging, Multi Object Spectroscopy of 198 sources was carried out, revealing 132 objects containing bona-fide Wolf-Rayet features. From this sample,

Georgios Choudalakis

Demonstration of how matter effects can result into non-oscillating neutrinos in vacuum, after they have passed through an appropriate distribution of matter. A brief discussion about matter effects in neutrinos oscillation is also made.

Jingshan Zhang, Boris I. Shklovskii

The conductivity of a granular metal or an array of quantum dots usually has the temperature dependence associated with variable range hopping within the soft Coulomb gap of density of states. This is difficult to explain because neutral dots have a hard charging gap at the Fermi level. We show that uncontrolled or intentional doping of the insulator around

D. S. Balsara, J. S. Kim, M. M. Mac Low, G. Mathews

Several lines of evidence suggest that protogalactic and galactic environments manage to grow magnetic field very rapidly. This makes the theoretical problem of achieving rapid growth of magnetic fields in such environments difficult. Following Balsara, Benjamin and Cox (2001), we show that a multiphase ISM that is dominated by realistic energy inputs via su

T. M. Aliev, V. Bashiry, M. Savci

We study the polarized lepton pair forward-backward asymmetries in (B -> K^* l^+ l^-) decay using a general, model independent form of the effective Hamiltonian. We present the general expression for nine double-polarization forward-backward asymmetries. It is shown that, the study of the forward-backward asymmetries of the doubly-polarized lepton pair is a

Dany Page, James M. Lattimer, Madappa Prakash, Andrew W. Steiner

A new classification of neutron star cooling scenarios, involving either ``minimal'' cooling or ``enhanced'' cooling is proposed. The minimal cooling scenario replaces and extends the so-called standard cooling scenario to include neutrino emission from the Cooper pair breaking and formation process. This emission dominates that due to the mo

Jan Rak

The properties of jets produced in p+p, d+Au and Au+Au collisions at sqrt{s_NN}=200 GeV are studied using the method of two particle correlations. The trigger particle is assumed to be a leading particle from a high p_T jet while the associated particle is assumed to come from either the same jet or the away jet. From the angular width and yield of the same

Viviana Acquaviva, Carlo Baccigalupi, Francesca Perrotta

We extend the theory of weak gravitational lensing to cosmologies with generalized gravity, described in the Lagrangian by a generic function depending on the Ricci scalar and a non-minimal coupled scalar field. We work out the generalized Poisson equations relating the dynamics of the fluctuating components to the two gauge invariant scalar gravitational po

P. F. Harrison, W. G. Scott

We motivate the simplest ansatz for the neutrino mass matrix consistent with the data from neutrino oscillation experiments, and admitting CP violation. It has only two free parameters: an arbitrary mass-scale and a small dimensionless ratio. This mass matrix exhibits two symmetries, Democracy and Mutativity, which respectively ensure trimaximal mixing of th

Wolfgang Soergel

We explain a strategy for a proof of the positivity of all coefficients of Kazhdan-Lusztig-polynomials for arbitrary Coxeter groups by constructing spaces whose dimensions we conjecture to be these coefficients.

Stefan Filipp, Erik Sjöqvist

Uhlmann's concept of quantum holonomy for paths of density operators is generalised to the off-diagonal case providing insight into the geometry of state space when the Uhlmann holonomy is undefined. Comparison with previous off-diagonal geometric phase definitions is carried out and an example comprising the transport of a Bell-state mixture is given.

Sameer M. Ikhdair, Ramazan Sever

We present bound state masses of the self-conjugate and non-self-conjugate mesons in the context of the Schrödinger equation taking into account the relativistic kinematics and the quark spins. We apply the usual interaction by adding the spin dependent correction. The pseudoscalar and vector decay constants of the $B_{c}$ meson and the unperturbed radial wa

Andreas Winter

Continuing our earlier work (quant-ph/0401060), we give two alternative proofs of the result that a noiseless qubit channel has identification capacity 2: the first is direct by a "maximal code with random extension" argument, the second is by showing that 1 bit of entanglement (which can be generated by transmitting 1 qubit) and negligible (quantum)

Munshi G. Mustafa, Markus H. Thoma, P. Chakraborty

The screening potential of a parton moving through a quark-gluon plasma is calculated using the semi-classical transport theory. An anisotropic potential showing a minimum in the direction of the parton velocity is found. As consequences possible new bound states and J/psi dissociation are discussed.

Metod Saniga, Michel Planat, Haret Rosu

It is conjectured that the question of the existence of projective planes whose order is not a power of prime is intimately linked with the problem whether there exists a set of d+1 mutually unbiased bases in a d-dimensional Hilbert space if d differs from a power of prime.

A. Ljubicic, D. Kekez, Z. Krecak, T. Ljubicic

We made a search for hadronic axions which could be emitted from the Sun in M1 transitions between the first 14.4 keV thermally excited and the ground state in Fe-57, and absorbed in the HPGe detector by axioelectric effect. An upper limit on hadronic axion mass of 400 eV is obtained at the 95% confidence level.

P. Zh. Aslanyan, V. N. Emelyanenko, G. G. Rikhkvitzkaya

The 2m propane bubble chamber experimental data have been analyzed to search for an exotic baryon state, the $Θ^+$ -baryon, in the $pK^0_s$ decay mode for the reaction p+$C_3H_8$ at 10 GeV/c. The $pK^0_s$ invariant mass spectrum shows resonant structures with $M_{K_s^0 p}$=1540$\pm$8, 1613$\pm$10, 1821$\pm$11 MeV/$c^2$ and $Γ_{K_s^0 p}$= 9.2$\pm$1.8, 16.1$\p

G. M. Beskin, S. V. Karpov

Magnetic field behaviour in a spherically-symmetric accretion flow for parameters typical of single black holes in the Galaxy is discussed. It is shown that in the majority of Galaxy volume, accretion onto single stellar-mass black holes will be spherical and have a low accretion rate ($10^{-6} - 10^{-9}$ of the Eddington rate). An analysis of plasma interna

Noriaki Kitazawa

We construct a supersymmetric composite model in type IIA T^6/(Z_2 x Z_2) orientifold with intersecting D6-branes. Four generations of quarks and leptons are naturally emerged as composite fields at low energies. Two pairs of light electroweak Higgs doublets are also naturally obtained. The hierarchical Yukawa couplings for the quark-lepton masses can be gen

S. Descotes-Genon, C. T. Sachrajda

We study the radiative decays B -> V gamma (where V=rho, K^*) in the framework of QCD factorisation, and in particular the hard-spectator contributions to the decay amplitudes. For the phenomenologically significant chromomagnetic operator, we show by an explicit next-to-leading-order computation that the spectator interactions factorise in the heavy-quark l

Anna Ochab-Marcinek, Ewa Gudowska-Nowak

We study the joint effect of thermal bath fluctuations and an external noise tuning activity of cytotoxic cells on the triggered immune response in a growing cancerous tissue. The immune response is assumed to be primarily mediated by effector cells that develop a cytotoxic activity against the abnormal tissue. The kinetics of such a reaction is represented

Anastasia Doikou

It is known that integrable models associated to rational $R$ matrices give rise to certain non-abelian symmetries known as Yangians. Analogously `boundary' symmetries arise when general but still integrable boundary conditions are implemented, as originally argued by Delius, Mackay and Short from the field theory point of view, in the context of the pri

X. F. Sun, Kouji Segawa, Yoichi Ando

It was recently demonstrated that in La_{2-x}Sr_{x}CuO_{4} the magnetic-field (H) dependence of the low-temperature thermal conductivity κup to 16 T reflects whether the normal state is a metal or an insulator. We measure the H dependence of κin YBa_{2}Cu_{3}O_{y} (YBCO) at subkelvin temperatures for a wide doping range, and find that at low doping the κ(H)

Biao Wu, Jie Liu, Qian Niu

A geometric phase is found for a general quantum state that undergoes adiabatic evolution. For the case of eigenstates, it reduces to the original Berry's phase. Such a phase is applicable in both linear and nonlinear quantum systems. Furthermore, this new phase is related to Hannay's angles as we find that these angles, a classical concept, can aris

Gleb V. Klimovitch

Classical feedback is defined here as the knowledge by the transmitter of the quantum state of the qubit received by the receiver. Such classical feedback doubles capacities of certain memoryless quantum channels without preexisting entanglement between transmitter and receiver. The increase in capacity, which is absent on classical memoryless channels, occu

S. N. Evangelou, D. E. Katsanos

Quantum chaos is linked to Brownian diffusion of the underlying quantum energy level-spacing sequences. The level-spacings viewed as functions of their order execute random walks which imply uncorrelated random increments of the level-spacings while the integrability to chaos transition becomes a change from Poisson to Gauss statistics for the level-spacing

P. Facchi, S. Tasaki, S. Pascazio, H. Nakazato

We analyze and compare three different strategies, all aimed at controlling and eventually halting decoherence. The first strategy hinges upon the quantum Zeno effect, the second makes use of frequent unitary interruptions ("bang-bang" pulses and their generalization, quantum dynamical decoupling), and the third of a strong, continuous coupling. Deco

Minh Duc Truong, Ba An Nguyen

We study the Hillery-type, i.e. $N$-th power, amplitude squeezing in the fan-state $| ξ;2k,f>_{F}$ characterized by $ξ\in \mathcal{C}$, $k=1,2,3,...$ and $f$ a nonlinear operator-valued function. We show that for a given $k$ there exists a critical $ξ_c$ such that for $0<|ξ|\leq|ξ_c|$ squeezing occurs simultaneously in $2k$ directions for the powers $N$ whic

Jakub S. Prauzner-Bechcicki

Entangled states play a crucial role in quantum information protocols, thus the dynamical behavior of entanglement is of a great importance. In this paper we consider a two-mode squeezed vacuum state coupled to one thermal reservoir as a model of an entangled state embedded in an environment. As a criterion for entanglement we use a continuous-variable equiv

Bulent Gonul, Okan Ozer, Mehmet Kocak

A mapping is obtained relating radial screened Coulomb systems with low screening parameters to radial anharmonic oscillators in N-dimensional space. Using the formalism of supersymmetric quantum mechanics, it is shown that exact solutions of these potentials exist when the parameters satisfy certain constraints.

J. H. Mueller, P. Petrov, D. Oblak, C. L. Garrido Alzar

We present a simple method to include the effects of diffraction into the description of a light-atomic ensemble quantum interface in the context of collective variables. Carrying out a scattering calculation we single out the purely geometrical effect. We apply our method to the experimentally relevant case of Gaussian shaped atomic samples stored in single

S. B. M. Bell, B. M. Diaz

We show that, in addition to radiation travelling at the speed of light, QED theory predicts a second type of radiation with an infinite velocity. We also show that charge, as it appears in the Dirac equation, may have a triune nature.

D. M. Beylin, A. I. Korchagin, A. S. Kuzmin, L. M. Kurdadze

This paper is devoted to the study of a degradation of CsI(Tl)crystals scintillation characteristics under irradiation with gamma-quanta at the uniformly distributed absorbed dose up to 3700 rad. The sample set consisted of 25 crystals of 30 cm long having a truncated pyramid shape and 30 rectangular crystals of the same length. A large difference in the lig

Aravindan Semparithi, Srihari Keshavamurthy

Considerable insights can be obtained regarding the nature of highly excited states by computing the eigenbasis expectation values of the resonance operators associated with an effective spectroscopic Hamiltonian. The expectation values are related to the parametric derivative of the eigenvalues with respect to specific resonance strengths i.e., level veloci

Bijaya K. Sahoo, Sonjoy Majumder, Rajat K. Chaudhuri, B. P. Das

Relativistic coupled-cluster(RCC) theory has been employed to calculate the life time of the $6 ^2P_{3/2}$ state of single ionized lead($^{207}Pb$) to an accurac y of 3% and compared with the corresponding value obtained using second order r elativistic many-body perturbation theory(RMBPT). This is one of the very few ap plications of this theory to excited

Bin Lin, H. Gordon Berry, Tomohiro Shibata, Lanlan Lin

We present VUV observations of transitions between doubly excited sextet states in O3+, F4+ and Ne5+. Spectra were produced by collisions of an oxygen, uorine and neon beam with a nitrogen gas jet target. Prepared beam-gas experiment yields new and explicit information on doubly core-excited ions. Some observed lines were assigned to the 1s2s2p3 6S-1s2p33s,

A. A. Usmani, F. H. Bhat, A. Abbas

The need for the three-body forces (3BF) for reproduction of physical properties of light nuclei has been evident for some time. These 3BF are doing quite well for light nuclei, but there seems to be scope for other 3BF which may arise from other physical considerations not included so far. Here we discuss a QCD motivated new 3BF which should be included in

V. G. Nosov, A. M. Kamchatnov

On the basis of the concept of the growing role of nonadiabatic effects of the non-conservation of the quantum number $K,$ a theory has been developed of the phenomenon which has been given the name of backbending. Above the transition point, for $J\geq J_c$, all the values $-J\leq K\leq J$ are equally probable. An investigation is made of the singularities

E. A. Novikov

Manipulation of the effects of consciousness by external influence on the human brain is considered in the context of the nonlinear dynamical modeling of interaction between automatic and conscious processes.

Sergio Curilef

In this work, simple exact results are presented for summations in two-particle potential with long-range interactions. Polygamma function is used to evaluate summations. Results are found when a periodic media is consider. Periodic boundary conditions are applied by symmetric repetitions of a central cell. Contributions over all space are used in the proble

B. Konopelchenko, L. Martinez Alonso

A general scheme for determining and studying integrable deformations of algebraic curves is presented. The method is illustrated with the analysis of the hyperelliptic case. An associated multi-Hamiltonian hierarchy of systems of hydrodynamic type is characterized.

Boris G. Konopelchenko, Antonio Moro

Geometrical optics limit of the Maxwell equations for nonlinear media with the Cole-Cole dependence of dielectric function and magnetic permeability on the frequency is considered. It is shown that for media with slow variation along one axis such a limit gives rise to the dispersionless Veselov-Novikov equation for the refractive index. It is demonstrated t

Miloslav Znojil

The list of properties of Fibonacci numbers F(n) (with multifaceted relevance in physics) is complemented by an empirical observation that in combination with the &#34;next&#34; family of the &#34;delayed Fibonacci&#34; numbers G(n) called, for convenience, &#34;Gibonacci numbers&#34; here, both sets exhibit certain remarkable and fairly unexpected asymptoti

J. Golenia, A. K. Prykarpatsky, Y. A. Prykarpatsky

An analog of Gelfand-Levitan-Marchenko integral equations for multi- dimensional Delsarte transmutation operators is constructed by means of studying their differential-geometric structure based on the classical Lagrange identity for a formally conjugated pair of differential operators. An extension of the method for the case of affine pencils of differentia

Y. A. Prykarpatsky, A. M. Samoilenko, A. K. Prykarpatsky, V. Hr. Samoylenko

The structure properties of multidimensional Delsarte-Darboux transmutation operators in parametric functional spaces is studied by means of differential-geometric and topological tools. It is shown that kernels of the corresponding integral operator expressions depend on the topological structure of related homological cycles in the coordinate space. As a n

Yarema Prykarpatsky, Anatoliy Samoilenko, Anatoliy K. Prykarpatsky

A differential geometrical and topological structure of Delsarte transmutation operators in multidimension is studied, the relationships with De Rham-Hodge-Skrypnik theory of generalized differential complexes is stated.

Alexander Yu. Vlasov

The spinor representation of the Lorentz group does not accept simple generalization with the group GL(4,R) of general linear coordinate transformations. The Dirac equation may be written for an arbitrary choice of a coordinate system and a metric, but the covariant linear transformations of the four-component Dirac spinor exist only for isometries. For usua

Dragutin Svrtan, Darko Veljan, Vladimir Volenec

An almost forgotten gem of Gauss tells us how to compute the area of a pentagon by just going around it and measuring areas of each vertex triangles (i.e. triangles whose vertices are three consecutive vertices of the pentagon). We give several proofs and extensions of this beautiful formula to hexagon etc. and consider special cases of affine--regular polyg

Ronaldo Garcia, Jorge Sotomayor

Associated to oriented surfaces immersed in R^3 here are studied pairs of transversal foliations with singularities, defined on the Elliptic region, where the Gaussian curvature K, given by the product of the principal curvatures k_1, k_2 of the immersion, is positive. The leaves of the foliations are the lines of M- mean curvature, along which the normal cu

Jacques Franchi, Yves Le Jan

The purpose of this note is to introduce and study a relativistic motion whose acceleration, in proper time, is given by a white noise. We begin with the flat case of special relativity, continue with the case of general relativity, and finally consider more closely the example of the Schwarzschild space.

D. Feyel, A. S. Ustunel

In this work we prove that the unique 1-convex solution of the Monge problem contructed from the solution of the Monge-Kantorovitch problem between the Wiener measure and a target measure which has a log-concave density w.r.to the Wiener measure is also the strong solution of the Monge-Ampere equation in the frame of infinite dimensional Frechet spaces. We e

Mathieu Baillif

Let R be Alexandroff&#39;s long ray. We prove that the homotopy classes of continuous maps R^n \to R are in bijection with the antichains of P({1,...,n}). The proof uses partition properties of continuous maps R^n \to R. We also provide a description of $[X,R]$ for some other non-metrizable manifolds X.

Michael Joswig, Frank H. Lutz

It is known that the suspension of a simplicial complex can be realized with only one additional point. Suitable iterations of this construction generate highly symmetric simplicial complexes with various interesting combinatorial and topological properties. In particular, infinitely many non-PL spheres as well as contractible simplicial complexes with a ver

H. Hakopian, M. Tonoyan

Starting with univariate polynomial interpolation we arrive to a natural generalization of fundamental theorem of algebra for certain systems of multivariate algebraic equations.

Radu Cascaval, Fritz Gesztesy

In this note we prove that the maximally defined operator associated with a class of Dirac-type differential expressions M(Q) is J-self-adjoint with respect to a proper antilinear conjugation J under the general hypothesis that the entries of the matrix potential coefficient Q are locally integrable on the real line. The Dirac-type differential expression M(

Lev Sakhnovich

In this article we consider a class of integrable operators and investigate its connections with the following theories:the spectral theory of non-self-adjoint operators, the Riemann-Hilbert problem, the canonical differential systems and the random matrices theory.

Alejandro S. Jakubi

Generalized power asymptotic expansions of solutions to differential equations that depend on parameters are investigated. The changing nature of these expansions as the parameters of the model cross critical values is discussed. An algorithm to identify these critical values and generate the generalized power series for distinct families of solutions is pre

George Gasper, Michael Schlosser

We deduce several curious q-series expansions by applying inverse relations to certain identities for basic hypergeometric series. After rewriting some of these expansions in terms of q-integrals, we obtain, in the limit q -> 1, some curious beta-type integral evaluations which appear to be new.

Wenxiong Chen, Ralph Howard, Erwin Lutwak, Deane Yang

A purely analytic proof is given for an inequality that has as a direct consequence the two most important affine isoperimetric inequalities of plane convex geometry: The Blaschke-Santalo inequality and the affine isoperimetric inequality of affine differential geometry.

Rui Loja Fernandes, Philippe Monnier

We review the linearization of Poisson brackets and related problems, in the formal, analytic and smooth categories.

Colin Guillarmou

We show that the resolvent of the Laplacian on asymptotically hyperbolic spaces extends meromorphically with finite rank poles to the complex plane if and only if the metric is `even&#39; (in a sense). If it is not even, there exist some cases where the resolvent has an essential singularity in the non-physical sheet.

Gonzalo Contreras

We prove that for a uniformly convex Lagrangian system L on a compact manifold M, almost all energy levels contain a periodic orbit. We also prove that below Ma ne&#39;s critical value of the lift of the Lagrangian to the universal cover, almost all energy levels have conjugate points. We prove that if the energy level [E=k] is of contact type and M is not t

Nathan Berkovits

Different string theories in twistor space have recently been proposed for describing ${\cal N}=4$ super-Yang-Mills. In this paper, my Strings 2003 talk is reviewed in which a string theory in $(x,\theta)$ space was constructed for self-dual ${\cal N}=4$ super-Yang-Mills. It is hoped that these results will be useful for understanding the twistor-string prop

Nick Evans, Jonathan P. Shock

We study the low energy dynamics of pions in a gravity dual of chiral symmetry breaking. The string theory construction consists of a probe D7 brane in the Constable Myers non-supersymmetric background, which has been shown to describe chiral symmetry breaking in the pattern of QCD. We expand the D7 brane&#39;s Dirac Born Infeld action for fluctuations that

Manoel M. Ferreira

One starts from a planar Maxwell-Chern-Simons model endowed with a Lorentz-violating term. The Dirac sector is introduced exhibiting a Yukawa and a minimal coupling with the scalar scalar and the gauge fields, respectively. One then evaluates the electron-electron interaction as the Fourier transform of the Moller scattering amplitude carried out in the non-

Carlo Contaldi, Lev Kofman, Marco Peloso

We consider warped compactifications in (4+d)-dimensional theories, with four dimensional de Sitter dS_4 vacua (with Hubble parameter H) and with a compact internal space. After introducing a gauge-invariant formalism for the generic metric perturbations of these backgrounds, we focus on modes which are scalar with respect to dS_4. The physical eigenmasses o

Helio Fagundes

A cosmology inspired structure for phase space is introduced, which leads to finitization and lattice-like discretization of position and momentum eigenvalues in a preferred, cosmic frame. Lorentz invariance is broken at very high energies, at present inaccessible. The divergent perturbation terms in quantum electrodynamics become finite and small; this coul

Artemio Gonzalez-Lopez, Toshiaki Tanaka

We construct a new family of N-fold supersymmetric systems which is referred to as ``type B&#39;&#39;. A higher derivative representation of the N-fold supercharge for this new family is given by a deformation of the type A N-fold supercharge. By utilizing the same method as in the sl(2) construction of type A N-fold supersymmetry, we show that this family i

A. Freitas

A weakly coupled new neutral gauge boson forms a narrow resonance that is hard to discover directly in e+e- collisions. However, if the gauge boson mass is below the center-of-mass energy, it can be produced through processes where the effective energy is reduced due to initial-state radiation and beamstrahlung. It is shown that at a high-luminosity linear c

Hong Li, Mingzhe Li, Xinmin Zhang

Recently Davoudiasl {\it et al} \cite{steinhardt} have introduced a new type of interaction between the Ricci scalar $R$ and the baryon current $J^μ$, ${\partial_μR} J^μ$ and proposed a mechanism for baryogenesis, the gravitational baryogenesis. Generally, however, $\partial_μ R$ vanishes in the radiation dominated era. In this paper we consider a generalize

A. Ferroglia, G. Ossola, A. Sirlin

Assuming that the Standard Model is correct and taking into account the lower bound on M_H from direct searches, we discuss bounds on M_W, M_top, and Sin^2 theta_eff_lept at various confidence levels. This permits to identify theoretically favored ranges for these important parameters in the Standard Model framework, regardless of other observables. As an il

The DELPHI Collaboration, J. Abdallah

The DELPHI experiment at the LEP e+e- collider collected almost 700 pb^-1 at centre-of-mass energies above the Z0 mass pole and up to 208 GeV. Those data were used to search for SUSY in the Anomaly Mediated SUSY Breaking (AMSB) scenario with a flavour independent common sfermion mass parameter. The searches covered several possible signatures experimentally

The BABAR Collaboration, B. Aubert

We search for B meson decays into two-body combinations of eta, eta&#39;, omega, and phi mesons from 89 million B B-bar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We find the branching fraction BF(B0 -> eta omega) = (4.0^{+1.3}_{-1.2} +- 0.4) x 10^-6 with a significance of 4.3 sigma. For all the other decay

Joachim Spengler

Measurements of the dependence of the J/Psi production cross section on its kinematic variables as well as on the target atomic numbers for 920 GeV/c protons incident on different targets have been made with the Hera-B detector. The large collected di-lepton sample allows to study the production ratio of Psi(2S) to J/Psi and of Chic to J/Psi . We also report

Olaf Wucknitz

We discuss the Sagnac effect in standard Minkowski coordinates and with an alternative synchronization convention. We find that both approaches lead to the same result without any contradictions. When applying standard coordinates to the complete rim of the rotating disk, a time-lag has to be taken into account which accounts for the global anisotropy. We pr

Mingsheng Ying

The (meta)logic underlying classical theory of computation is Boolean (two-valued) logic. Quantum logic was proposed by Birkhoff and von Neumann as a logic of quantum mechanics more than sixty years ago. The major difference between Boolean logic and quantum logic is that the latter does not enjoy distributivity in general. The rapid development of quantum c

Shih-Hui Chang, Allen Taflove, Alexey Yamilov, Aleksander Burin

We applied finite difference time domain (FDTD) algorithm to the study of field and intensity correlations in random media. Close to the onset of Anderson localization, we observe deviations of the correlation functions, in both shape and magnitude, from those predicted by the diffusion theory. Physical implications of the observed phenomena are discussed.

J. Lefebvre, P. Finnie, Y. Homma

Photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy of pillar-suspended single-walled carbon nanotubes has been measured for temperatures between 300 K and 5 K.

R. J. Radwanski, Z. Ropka

We have calculated the discrete low-energy electronic structure in LaMnO3 originating from the atomic-like states of the strongly correlated 3d4 electronic system occurring in the Mn3+ ion. We take into account very strong intra-atomic correlations, crystal field interactions and the intra-atomic spin-orbit coupling. We calculated magnetic and paramagnetic s

Belal Baaquie, Jean-Philippe Bouchaud

The simplest field theory description of the multivariate statistics of forward rate variations over time and maturities, involves a quadratic action containing a gradient squared rigidity term. However, this choice leads to a spurious kink (infinite curvature) of the normalized correlation function for coinciding maturities. Motivated by empirical results,

B. Doucot, M. V. Feigel&#39;man, L. B. Ioffe, A. S. Ioselevich

We present general symmetry arguments that show the appearance of doubly denerate states protected from external perturbations in a wide class of Hamiltonians. We construct the simplest spin Hamiltonian belonging to this class and study its properties both analytically and numerically. We find that this model generally has a number of low energy modes which

Apoorva Nagar, Mustansir Barma, Satya N. Majumdar

We study the clustering properties of advected, non-interacting,passive scalar particles in a Burgers fluid with noise, a problem which maps to that of passive sliding particles moving under gravity on a surface evolving through the Kardar-Parisi-Zhang equation. Numerical simulations show that both the density-density correlation function and the single-site

Alvaro S. Núñez, A. H. MacDonald

We propose a general theory of the spin-transfer effects that occur when current flows through inhomogeneous magnetic systems. Our theory does not rest on an appeal to conservation of total spin, can assess whether or not current-induced magnetization precession and switching in a particular geometry will occur coherently, and can estimate the efficacy of sp

Anisur Rahman, Mark S. Lundstrom, Avik W. Ghosh

The general theory for quantum simulation of cubic semiconductor n-MOSFETs is presented within the effective mass equation approach. The full three-dimensional transport problem is described in terms of coupled transverse subband modes which arise due to quantum confinement along the body thickness direction. Couplings among the subbands are generated for tw

Leticia Cugliandolo, Gustavo Lozano, Homero Lozza

We apply the Kovacs experimental protocol to classical and quantum p-spin models. We show that these models have memory effects as those observed experimentally in super-cooled polymer melts. We discuss our results in connection to other classical models that capture memory effects. We propose that a similar protocol applied to quantum glassy systems might b

Peihong Zhang, Weidong Luo, Vincent H. Crespi, Marvin L. Cohen

A systematic LSDA+U study of doping effects on the electronic and structural properties of single layer CoO2 is presented. Undoped CoO2 is a charge transfer insulator within LSDA+U and a metal with a high density of states (DOS) at the Fermi level within LSDA. (CoO2)$^{1.0-}$, on the other hand, is a band insulator with a gap of 2.2 eV. Systems with fraction

D. B. Lukatsky, Daan Frenkel

We propose that the first stage of membrane fusion need not be the formation of a single stalk. Instead, we consider a scenario for defect-induced membrane fusion that proceeds cooperatively via multiple stalk formation. The defects (stalks or pores) attract each other via membrane-mediated capillary interactions that result in a condensation transition of t

K. A. Snyder, T. R. Kirkpatrick

The localization length for isotopically disordered harmonic one-dimensional chains is calculated for arbitrary impurity concentration and scattering cross section. The localization length depends on the scattering cross section of a single scatterer, which is calculated for a discrete chain having a wavelength dependent pulse propagation speed. For binary i

A. Kohen, F. Giubileo, Th. Proslier, F. Bobba

Using Scanning Tunneling Microscope at low temperature we explore the superconducting phase diagram in the $π$-band of the two-band superconductor MgB$_2$. In this band the peculiar shape of the local tunneling spectra and their dynamics in the magnetic field reveal the complex character of the quasiparticle density of states (DOS). The gap in the DOS is fir

P. S. Dodds, D. J. Watts

Models of contagion arise broadly both in the biological and social sciences, with applications ranging from the transmission of infectious diseases to the diffusion of innovations and the spread of cultural fads. In this Letter, we introduce a general model of contagion which, by explicitly incorporating memory of past exposures to, for example, an infectio

Eugene M. Chudnovsky

Symmetry implications for the decoherence of quantum oscillations of a two-state system in a solid are studied. When the oscillation frequency is small compared to the Debye frequency, the universal lower bound on the decoherence due to the atomic environment is derived in terms of the macroscopic parameters of the solid, with no unknown interaction constant

A. Yu. Rusanov, M. Hesselberth, J. Aarts, A. I. Buzdin

In (S/F) hybrids the suppression of superconductivity by the exchange field h_ex of the ferromagnet can be partially lifted when different directions of h_ex are sampled simultaneously by the Cooper pair. In F/S/F trilayer geometries where the magnetization directions of the two F-layers can be controlled separately, this leads to the so-called spin switch.

A. Maignan, V. Hardy, S. Hebert, M. Drillon

The magnetic behavior of the Ca3Co2O6 spin chain compound is characterized by a large Ising-like character of its ferromagnetic chains, set on triangular lattice, that are antiferromagnetically coupled. At low temperature, T < 7K, the 3D antiferromagnetic state evolves towards a spin frozen state. In this temperature range, magnetic field driven magnetizatio

Giorgos Fagas, Agapi Kambili

We present a comprehensive study of the properties of the off-resonant conductance spectrum in oligomer nanojunctions between graphitic electrodes. By employing first-principle-based methods and the Landauer approach of quantum transport, we identify how the electronic structure of the molecular junction components is reflected in electron transport across s

Beate Dorow, Dominic Widdows, Katarina Ling, Jean-Pierre Eckmann

We introduce two different approaches for clustering semantically similar words. We accommodate ambiguity by allowing a word to belong to several clusters. Both methods use a graph-theoretic representation of words and their paradigmatic relationships. The first approach is based on the concept of curvature and divides the word graph into classes of similar

Paolo De Gregorio, Aonghus Lawlor, Phil Bradley, Kenneth A. Dawson

We study the onset of the bootstrap percolation transition as a model of generalized dynamical arrest. We develop a new importance-sampling procedure in simulation, based on rare events around &#34;holes&#34;, that enables us to access bootstrap lengths beyond those previously studied. By framing a new theory in terms of paths or processes that lead to empty

C. Cosmelli, M. G. Castellano, F. Chiarello, R. Leoni

We show a novel method for controlling the coupling of flux-based qubits by means of a superconducting transformer with variable flux transfer function. The device is realized by inserting a small hysteretic dc SQUID with unshunted junctions, working as a Josephson junction with flux controlled critical current, in parallel to a superconducting transformer;

Udo Schwingenschloegl, Volker Eyert

To compare the metal-insulator transitions (MITs) of VO2 and V2O3 we analyze the relations between the structural and electronic properties of the vanadium Magneli phases. These materials set up the homologous series VnO(2n-1) (3 <= n <= 9) and have crystal structures comprising typical dioxide-like and sesquioxide-like regions. As the MITs of the vanadium M