September 2000 arXiv papers — page 20

Jeremy Kepner

The NVOs core data mining and archive federation activities are heavily dependent on the underlying data pipeline software necessary to translate the raw data into scientifically relevant source detections. The data pipeline software dictates: the raw data storage and retrieval mechanisms, the meaning and format of the fields in the source catalogs, and the

Jun'ichi Yokoyama

Cosmological N-body simulations with scale-invariant initial perturbations show too many virialized objects of dwarf-galaxy masses in a typical galactic halo in contradiction to observation and stability of galactic discs. We present a model of double hybrid inflation which predicts density fluctuations with a small-scale cutoff to account for the absence of

Arthur M. Wolfe

Evidence is presented that the damped Lyman alpha absorption systems are the high-redshift (z > 3) progenitors of galaxy disks. I discuss kinematic evidence that the damped Lyman Alpha systems are rotating disks. I also discuss implications of the lack of metal-poor damped Lyman alpha systems with line width Delta v > 100 {\kms}. I then present new evidence

Chris Adami, Steven E. Koonin

We study the utility of a complex Langevin (CL) equation as an alternative for the Monte Carlo (MC) procedure in the evaluation of expectation values occurring in fermionic many-body problems. We find that a CL approach is natural in cases where non-positive definite probability measures occur, and remains accurate even when the corresponding MC calculation

A. J. M. Medved, G. Kunstatter

We consider the one-loop corrected geometry and thermodynamics of a rotating BTZ black hole by way of a dimensionally reduced dilaton model. The analysis begins with a comprehensive study of the non-extremal solution after which two different methods are invoked to study the extremal case. The first approach considers the extremal limit of the non-extremal c

D. Blaschke, H. Grigorian, D. N. Voskresensky

We study the consequences of superconducting quark cores (with color-flavor-locked phase as representative example) for evolution of temperature profiles and the cooling curves in quark-hadron hybrid stars and in hypothetical self-bounded objects having no a hadron shell (quark core neutron stars). The quark gaps are varied from 0 to $Δ_q =50$ MeV. For hybri

L. Frankfurt, M. McDermott, M. Strikman

We quantify perturbative and non-perturbative QCD effects in the exclusive $J/\psi$-photoproduction cross section, and in the shrinkage of the differential cross section with respect to momentum transfer, $t$. We predict that in the high energy THERA region there will always be a significant contribution to this process that rises quickly with energy. This i

W. F. Kao

We show that there is a class of regular charged black hole with a charged de Sitter core similar to the de Sitter-Schwarzschild black hole. One can show that the total energy momentum tensor for the static and spherically symmetric photon field can be made conserved even the Coulomb like energy momentum tensor for photon is not conserved alone. Possible imp

Oliver Muelken, Peter Borrmann

Using a recently proposed classification scheme for phase transitions in finite systems [Phys.Rev.Lett.{\bf 84},3511 (2000)] we show that within the statistical standard model of nuclear multifragmentation the predicted phase transition is of first order.

V. Gimenez, J. Reyes

We present recent results for the prediction of the Bs lifetime difference from lattice Heavy Quark Effective Theory simulations. In order to get a next-to-leading order result we have calculated the matching between QCD and HQET and the two loop anomalous dimension in the HQET for all the ΔB=2 operators, in particular for the operators which enter in the wi

Michael Melles

The perturbatively calculable short distance QCD potential is known to two loops including the effect of massive quarks. Recently, a simple approximate solution in momentum space was utilized to obtain the potential in coordinate space. The latter is important in several respects. A comparison with non-perturbative lattice results is feasible in the overlap

Andrei N. Soklakov

We introduce the principle of Occam's Razor in a form which can be used as a basis for economical formulations of physics. This allows us to explain the general structure of the Lagrangian for a composite physical system, as well as some other artificial postulates behind the variational formulations of physical laws. As an example, we derive Hamilton&#3

L. Andrianopoli, F. Cordaro, P. Fre', L. Gualtieri

We reformulate maximal D=5 supergravity in the consistent approach uniquely based on Free Differential Algebras and the solution of their Bianchi identities (= rheonomic method). In this approach the lagrangian is unnecessary since the field equations follow from closure of the supersymmetry algebra. This enables us to explicitly construct the non-compact ga

A. D. Dolgov, S. H. Hansen

We show that massive sterile neutrinos mixed with the ordinary ones may be produced in the early universe in the right amount to be natural warm dark matter particles. Their mass should be below 40 keV and the corresponding mixing angles sin^2 2θ> 10^{-11} for mixing with ν_μor ν_τ, while mixing with ν_e is slightly stronger bounded with mass less than 30 ke

Radu Ionicioiu, Paolo Zanardi, Fausto Rossi

We propose an experiment to test Bell's inequality violation in condensed-matter physics. We show how to generate, manipulate and detect entangled states using ballistic electrons in Coulomb-coupled semiconductor quantum wires. Due to its simplicity (only five gates are required to prepare entangled states and to test Bell's inequality), the proposed

C. S. Kim, Sechul Oh

We propose a new method to extract the CP violating weak phase $γ$ (the phase of $V_{ub}^*$) in the CKM paradigm of the Standard Model, using $B^- \rightarrow D^0 π^- \rightarrow f π^-$ and $B^- \rightarrow \bar D^0 π^- \rightarrow f π^-$ decays, where $f$ are final states such as $K^+ π^-$, $K^+ ρ^-$, $K ππ$, {\it etc.} We also study the experimental feasib

D. Puy, L. Grenacher, Ph. Jetzer, M. Signore

In this paper we investigate the Sunyaev-Zel'dovich (SZ) effect and the X-ray surface brightness for clusters of galaxies with a non-spherical mass distribution. In particular, we consider the influence of the shape and the finite extension of a cluster as well as of a polytropic thermal profile on the Compton parameter, the X-ray surface brightness and

Björn Brinne, Ansar Fayyazuddin, Subir Mukhopadhyay, Douglas J. Smith

We find solutions of 11-dimensional supergravity for M5-branes wrapped on Riemann surfaces. These solutions preserve ${\cal N} = 2$ four-dimensional supersymmetry. They are dual to ${\cal N} = 2$ gauge theories, including non-conformal field theories. We work out the case of ${\cal N} = 2$ Yang-Mills in detail.

S. Alexeyev, A. Toporensky, V. Ustiansky

We investigate Bianchi I cosmological model in the theory of a dilatonM field coupled to gravity through a Gauss-Bonnet term. Two type ofM cosmological singularity are distinguished. The former is analogous toM the Einstein gravity singularity, the latter (which does not appear inM classical General Relativity) occurs when the main determinant of theM system

A. Gashi, E. Matsinos, G. C. Oades, G. Rasche

Using newly calculated electromagnetic corrections, we have made a phase shift analysis of experimental data on pi+/- p elastic scattering up to 100 MeV, assuming the effective hadronic interaction to be isospin invariant. The output consists of parametrised s and p-wave hadronic phases for isospin 1/2 and 3/2. It is not possible to fit the charge exchange d

A. Baldassarri, U. Marini Bettolo Marconi, A. Puglisi, A. Vulpiani

We study fluidized granular gases in a stationary state determined by the balance between an external driving and the bulk dissipation. The two considered situations are inspired by recent experiments, where the gravity plays a major role as a driving mechanism: in the first case gravity acts only in one direction and the bottom wall is vibrated, in the seco

Mircea Neagu, Constantin Udriste

A geometrization of a Kronecker $h$-regular multi-time Lagrangian function with partial derivatives of order one is described, in the sense of d-connections, d-torsions and d-curvatures.

Mircea Neagu

The paper introduces the notion of h-normal Γ-linear connection \nabla on 1-jet fibre bundle J^1(T,M), and studies its local d-torsions and d-curvatures togheter with theirs Bianchi identities. Also, it presents the important deflection d-tensors identities attached to \nabla.

Mircea Neagu, Constantin Udriste

The paper introduces the notion of Γ-linear connection \nabla on the 1-jet fibre bundle J^1(T,M), and presents its local components. We also describe the local Ricci and Bianchi identities of $\nabla$.

N. Sh. Izmailian, Chin-Kun Hu

We have derived analytic expressions for the amplitudes of correction terms in the critical free energy and inverse correlation length expansions for square, honeycomb, and plane-triangular lattices in strip geometry. We have found that ratio of amplitudes for all of these lattices is universal. We have also obtained similar expansions for the ground state e

Sacha Davidson, Subir Sarkar

During (re)heating of the universe after inflation, the relativistic decay products of the inflaton field $ϕ$ must lose energy and additional particles must be produced to attain a thermalised state at a temperature $T_{\reh}$. We estimate the rate of energy loss via elastic and inelastic scattering interactions. Elastic scattering is an inefficient energy l

Masahisa Matsuda, Takeo Matsuoka

The lepton masses and mixings are studied on the basis of string inspired $SU(6)\times SU(2)_R$ model with global flavor symmetries. Provided that sizable mixings between lepton doublets $L$ and Higgsino-like fields $H_d$ with even R-parity occur and that seesaw mechanism is at work in the neutrino sector, the model can yield a large mixing angle solution wi

Jean-Luc Thiffeault, Allen H. Boozer

Constraints are found on the spatial variation of finite-time Lyapunov exponents of two and three-dimensional systems of ordinary differential equations. In a chaotic system, finite-time Lyapunov exponents describe the average rate of separation, along characteristic directions, of neighboring trajectories. The solution of the equations is a coordinate trans

Xin-Nian Wang

Parton energy loss inside a dense medium leads to the suppression of large $p_T$ hadrons and can also cause azimuthal anisotropy of hadron spectra at large transverse momentum in non-central high-energy heavy-ion collisions. Such azimuthal anisotropy is studied qualitatively in a parton model for heavy-ion collisions at the RHIC energies. The coefficient $v_

Brett Bolen, Luca Bombelli, Raymond Puzio

We point out the existence of new effects of global spacetime expansion on local binary systems. In addition to a possible change of orbital size, there is a contribution to the precession of elliptic orbits, to be added to the well-known general relativistic effect in static spacetimes, and the eccentricity can change. Our model calculations are done using

Adan Cabello

A general proof of the security against eavesdropping of a previously introduced protocol for two-party quantum key distribution based on entanglement swapping [Phys. Rev. A {\bf 61}, 052312 (2000)] is provided. In addition, the protocol is extended to permit multiparty quantum key distribution and secret sharing of classical information.

Radford M. Neal

Markov chain sampling methods that automatically adapt to characteristics of the distribution being sampled can be constructed by exploiting the principle that one can sample from a distribution by sampling uniformly from the region under the plot of its density function. A Markov chain that converges to this uniform distribution can be constructed by altern

C. Schwarz

Proton-proton correlations and correlations of p-alpha, d-alpha, and t-alpha from spectator decays following Au + Au collisions at 1000 AMeV have been measured with an highly efficient detector hodoscope. The constructed correlation functions indicate a moderate expansion and low breakup densities similar to assumptions made in statistical multifragmentation

K. L. Vaninsky

An invariant Gibbs' state for the nonlinear Schrodinger equation on the circle was constructed by Bourgain, and McKean, out of the basic Hamiltonian using a trigonometric cut-off. The cubic nonlinear Schrodinger equation is a completely integrable system having an infinite number of additional integrals of motion. In this paper we construct the second in

Tanya Araujo, R. Vilela Mendes

The main problem we address in this paper is whether function determines form when a society of agents organizes itself for some purpose or whether the organizing method is more important than the functionality in determining the structure of the ensemble. As an example, we use a neural network that learns the same function by two different learning methods.

Abhik Basu

We study the effects of crosscorrelations of noises on the scaling properties of the correlation functions in a reduced model for Magnetohydrodynamic (MHD) turbulence [A. Basu, J.K Bhattacharjee and S. Ramaswamy [{\em Eur. Phys. J B} {\bf 9}, 725 (1999)]. We show that in {\em dimension d} crosscorrelations with sufficient long wavelength singularity become r

Saharon Shelah, Jouko Väänänen

We show that a strong form of the so called Lindstrom's Theorem fails to generalize to extensions of L_{kappa,omega} and L_{kappa,kappa}: For weakly compact kappa there is no strongest extension of L_{kappa,omega} with the (kappa,kappa)-compactness property and the Lowenheim-Skolem theorem down to kappa. With an additional set-theoretic assumption, there

Menachem Kojman, Saharon Shelah

We prove that for every singular cardinal mu of cofinality omega, the complete Boolean algebra compP_mu(mu) contains as a complete subalgebra an isomorphic copy of the collapse algebra Comp Col(omega_1,mu^{aleph_0}). Consequently, adding a generic filter to the quotient algebra P_mu(mu)=P(mu)/[mu]^{<mu} collapses mu^{aleph_0} to aleph_1. Another corollary is

Mirna Džamonja, Saharon Shelah

In this paper we investigate some properties of first order theories which prevent them from having universal models under certain cardinal arithmetic assumptions. Our results give a new syntactical condition, oak property, which is a sufficient condition for a theory not to have universal models in cardinality lambda when certain cardinal arithmetic assumpt

Heike Mildenberger, Saharon Shelah

We prove the consistency result from the title. By forcing we construct a model of g=aleph_1, b=cf(Sym(omega))=aleph_2.

Mark J. Gotay, Janusz Grabowski, Bryon Kaneshige

We study the algebraic structure of the Poisson algebra P(O) of polynomials on a coadjoint orbit O of a semisimple Lie algebra. We prove that P(O) splits into a direct sum of its center and its derived ideal. We also show that P(O) is simple as a Poisson algebra iff O is semisimple.

Saharon Shelah

We prove that for any superatomic Boolean Algebra of cardinality >beth_omega there is an automorphism moving uncountably many atoms. Similarly for larger cardinals. Any of those results are essentially best possible.

Éric Ricard

Let H^1 be the classical Hardy space of analytic functions on the unit disc. We show that this space does not admit any finite rank completely unconditional decomposition of the identity.

Joaquim Martin, Javier Soria

Associated to the class of restricted-weak type weights for the Hardy operator, we find a new class of Lorentz spaces for which the normability property holds. This result is analogous to the characterization given by Sawyer for the classical Lorentz spaces. We also show that these new spaces are very natural to study the existence of equivalent norms descri

A. Bonami, D. Buraczewski, E. Damek, A. Hulanicki

We consider the Johnson-Koranyi-Hua system on symmetric Siegel domains of type two. We prove that all functions which are annihilated by the system and satisfy an H^2 integrability condition are pluriharmonic. So the situation is completely different on type two domains than on tube type domains: it was proved by Johnson and Koranyi that on symmetric tube ty

A. Spiro

It is proved that all invariant functions of a complex Finsler manifold can be totally recovered from the torsion and curvature of the connection introduced by Kobayashi for holomorphic vector bundles with complex Finsler structures. Equations of the geodesics and Jacobi fields of a generic complex Finsler manifold, expressed by means Kobayashi&#39;s connect

Timothy J. Hodges, Milen Yakimov

Let G be a connected, simply connected Poisson-Lie group with quasitriangular Lie bialgebra g. An explicit description of the double D(g) is given, together with the embeddings of g and g^*. This description is then used to provide a construction of the double D(G). The aim of this work is to describe D(G) in sufficient detail to be able to apply the procedu

Gary T. Horowitz, Veronika E. Hubeny

By the AdS/CFT correspondence, the expectation value of certain local operators in the CFT is given by the asymptotic value of supergravity fields. We show that these local expectation values contain a remarkable amount of information about small sources deep inside AdS_p x S^q. In particular, they contain essentially all the multipole moments. More importan

Hiroshi Nunokawa

We review the status of the solutions to neutrino anomalies by flavor-changing as well as flavor-diagonal neutrino interactions. While it is difficult to explain the atmospheric neutrino data the solar neutrino data can be well accounted for by the massless neutrino oscillation induced by such non-standard neutrino interactions. We also discuss the possibili

Hisakazu Minakata, Hiroshi Nunokawa

In this talk we discuss the possibility to measure CP violation in neutrino oscillation experiments using the neutrino beam with energy which is lower (E_ν\gsim 100 MeV) than the one usually considered (typically > 1 GeV) in accelerator experiments. The advantage of using such lower energy neutrino beam is that despite the smaller detection cross sections, t

R L Thews, M Schroedter, J Rafelski

At RHIC the cross section for c-cbar production will be large enough such that approximately 10 pairs will be produced in each central collision. If a region of deconfined quarks and gluons is subsequently formed, one would expect that the mobility of the charm quarks will enable them to form J/Psi through &#34;off-diagonal&#34; combinations, involving a qua

Alexander Kusenko

Supersymmetric extensions of the Standard Model predict the existence of Q-balls, some of which can be entirely stable. Affleck-Dine baryogenesis can result in a copious production of stable baryonic Q-balls, which can presently exist as a form of dark matter.

Joachim Hein

We discuss recent results on the excitation spectra of B and D-mesons obtained in the framework of non-relativistic lattice QCD in the quenched approximation. The results allow for the determination of the $\msbar$-mass of $m_{b,\msbar}(m_{b,\msbar})= 4.34(7)$ GeV in ${\cal O}(α_s^3)$ in the perturbative matching. The determination of the decay constants f_{

N. Nimai Singh

We study the effective ways for generating the linear see-saw neutrino mass relations and large neutrino mixing angles in two classes of grand unified SO(10) models where the texture of Dirac neutrino mass matrix is related to either the charged lepton mass matrix (case A) or the up-quark mass matrix (case B). We also briefly analyse their stability criteria

W. Bernreuther, A. Brandenburg, P. Uwer

In this talk we discuss the calculation of the QCD corrections to parity-violating 3-jet observables in e^+e^- collisions, keeping the full quark mass dependence.

A. Gashi, E. Matsinos, G. C. Oades, G. Rasche

We calculate the electromagnetic corrections to the isospin invariant mixing angle and to the two eigenphases for the s and p-waves for low energy pi-p elastic and charge exchange scattering. These corrections have to be applied to the nuclear quantities obtained from phase shift analyses of the experimental data in order to obtain the hadronic phases. We co

A. Gashi, E. Matsinos, G. C. Oades, G. Rasche

We calculate the s and p-wave electromagnetic corrections which must be subtracted from the nuclear phase shifts obtained from the analysis of low energy pi+p elastic scattering data, in order to obtain hadronic phase shifts. We compare our results with earlier calculations and estimate the uncertainties in the corrections.

Harleen Dahiya, Manmohan Gupta

The implications of Chiral Quark Model with SU(3) and axial U(1) symmetry breakings as well as configuration mixing generated by one gluon exchange forces ($χ$QM$_{gcm}$) are discussed in context of proton flavor and spin structure as well as hyperon $β$-decay data. Apart from reproducing the success of $χ$QM with symmetry breaking, it is able to improve upo

M. Guagnelli, K. Jansen, R. Petronzio

We present the results of a non-perturbative determination of the pion matrix element of the twist-2 operator corresponding to the average momentum of non-singlet quark densities. The calculation is made within the Schroedinger functional scheme. We report the results of simulations done with the standard Wilson action and with the non-perturbatively improve

G. Chiodini, J. A. Appel, M. Artuso, J. N. Butler

The results of the BTeV silicon pixel detector beam test carried out at Fermilab in 1999-2000 are reported. The pixel detector spatial resolution has been studied as a function of track inclination, sensor bias, and readout threshold.

The OPAL collaboration, G. Abbiendi

A measurement of triple gauge boson couplings is presented, based on W-pair data recorded by the OPAL detector at LEP during 1998 at a centre-of-mass energy of 189 GeV with an integrated luminosity of 183 pb^-1. After combining with our previous measurements at centre-of-mass energies of 161-183 GeV we obtain k_g=0.97 +0.20 -0.16, g_1^z=0.991 +0.060 -0.057 a

The OPAL collaboration, G. Abbiendi

Measurements are presented of the polarisation of W+W- boson pairs produced in e+e- collisions, and of CP-violating WWZ and WWGamma trilinear gauge couplings. The data were recorded by the OPAL experiment at LEP during 1998, where a total integrated luminosity of 183 pb^-1 was obtained at a centre-of-mass energy of 189 GeV. The measurements are performed thr

The OPAL collaboration, G. Abbiendi

Using data recorded at centre-of-mass energies around 183 GeV and 189 GeV with the OPAL detector at LEP, the fundamental coupling of the charm quark to the W boson has been studied. The ratio Rc^W = Gamma(W -> cX)/Gamma(W -> hadrons) has been measured from jet properties, lifetime information, and leptons produced in charm decays. A value compatible with the

The OPAL collaboration, G. Abbiendi

From a data sample of 183 pb^-1 recorded at a center-of-mass energy of roots = 189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are selected. Assuming Standard Model W boson decay branching fractions, the W-pair production cross section is measured to be sigmaWW = 16.30 +- 0.34(stat.) +- 0.18(syst.) pb. When combined with previous OPAL mea

The OPAL collaboration, G. Abbiendi

The mass and width of the W boson are determined in e+e- collisions at LEP using 183 pb^-1 of data recorded at a centre-of-mass energy roots=189 GeV with the OPAL detector. The invariant mass distributions from 970 WW->qqqq and 1118 WW->qqln candidate events are used to measure the mass of the W boson, Mw = 80.451 +- 0.076(stat.) +- 0.049(syst.) GeV. A direc

The OPAL collaboration, G. Abbiendi

From an analysis of the ionisation energy loss of charged particles selected from 110326 e+e- -> tau+tau- candidates recorded by the OPAL detector at e+e- centre-of-mass energies near the Z0 resonance, we determine the one-prong tau decay branching ratios: Br(tau- -> nu_tau K- >=0h0) = 1.528 +- 0.039 +- 0.040 % Br(tau- -> nu_tau K-) = 0.658 +- 0.024 +- 0.029

P. Klepac, J. Horsky

The aim of this paper is to examine some obtained exact solutions of the Einstein-Maxwell equations, especially their properties from a chronological point of view. Each our spacetime is stationary cylindrically symmetric and it is filled up with an perfect fluid that is electrically charged. There are two classes of solutions and examples of each of them ar

Alejandro Perez, Carlo Rovelli

We present a spin foam formulation of Lorentzian quantum General Relativity. The theory is based on a simple generalization of an Euclidean model defined in terms of a field theory over a group. Its vertex amplitude turns out to be the one recently introduced by Barrett and Crane. As in the case of its Euclidean relatives, the model fully implements the desi

Franco Bagnoli

The derivatives of a Boolean function are defined up to any order. The Taylor and MacLaurin expansions of a Boolean function are thus obtained. The last corresponds to the ring sum expansion (RSE) of a Boolean function, and is a more compact form than the usual canonical disjunctive form. For totalistic functions the RSE allows the saving of a large number o

Noriko Akutsu, Yasuhiro Akutsu, Takao Yamamoto

We study the vicinal surface with adsorption below the roughening temperature, using the restricted solid-on-solid model coupled with the Ising model. We calculate the step tension $γ$ and the step-interaction coefficient $B$ by employing a variant of the density matrix algorithm. We find a ``stiffening transition&#39;&#39; at a temperature $T_{\rm s}$ where

Vincenzo Piazza, Fabio Beltram, Werner Wegscheider, Chi-Te Liang

Aharonov-Bohm (AB) interference is reported for the first time in the conductance of a vertical nanostructure based on a single GaAs/AlGaAs quantum well (QW). The two lowest subbands of the well are spatially separated by the Hartree barrier originating from electronic repulsion in the modulation-doped QW and provide AB two-path geometry. Split-gates control

W. Stephan, B. W. Southern

The phase diagram of the classical anisotropic (XXZ) Heisenberg model on the 2-dimensional triangular lattice is investigated using Monte Carlo methods. In the easy-axis limit, two finite temperature vortex unbinding transitions have been observed. In the easy-plane limit, there also appear to be two distinct finite temperature phase transitions. The upper t

J. A. White, S. Velasco

In this article we show that the inhomogeneous density obtained from a density-functional theory of classical fluids in the canonical ensemble (CE), recently presented by White et al [Phys. Rev. Lett. 84 (2000) 1220], is equivalent to first order to the result of the series expansion of the CE inhomogeneous density introduced by Gonzalez et al [Phys. Rev. Le

J. A. White, S. Velasco

A general density-functional formalism using an extended variable-space is presented for classical fluids in the canonical ensemble (CE). An exact equation is derived that plays the role of the Ornstein-Zernike (OZ) equation in the grand canonical ensemble (GCE). When applied to the ideal gas we obtain the exact result for the total correlation function h_N.

J. C. Cuevas, A. Levy Yeyati, A. Martin-Rodero

We study the transport properties of a quantum dot coupled to a normal and a superconducting lead. The dot is represented by a generalized Anderson model. Correlation effects are taken into account by an appropriate self-energy which interpolates between the limits of weak and strong coupling to the leads. The transport properties of the system are controlle

A. V. Balatsky, P. Kumar, J. R. Schrieffer

We consider a superconducting state with a mixed symmetry order parameter components, e.g. $d+is$ or $d+id&#39;$ with $d&#39;= d_{xy}$. We argue for the existence of the new orbital magnetization mode which corresponds to the oscillations of relative phase $ϕ$ between two components around an equilibrium value of $ϕ= \fracπ{2}$. It is similar to the so calle

R. Rajesh, Satya N. Majumdar

We revisit a simple lattice model of aggregation in which masses diffuse and coalesce upon contact with rate 1 and every nonzero mass chips off a single unit of mass to a randomly chosen neighbour with rate $w$. The dynamics conserves the average mass density $ρ$ and in the stationary state the system undergoes a nonequilibrium phase transition in the $(ρ-w)

Ivan Dornic, Anaël Lemaître, Andrea Baldassarri, Hugues Chaté

We present a general scheme to calculate within the independent interval approximation generalized (level-dependent) persistence properties for processes having a finite density of zero-crossings. Our results are especially relevant for the diffusion equation evolving from random initial conditions, one of the simplest coarsening systems. Exact results are o

T. Knetter, G. Schröder, M. J. Alava, H. Rieger

The competing effect of a periodic pinning potential and random point disorder is studied for arrays of elastic lines or directed polymers. The groundstates are investigated by exact combinatorial optimization. In both two and three dimensions a phase diagram is found with two or three distinct phases: a strictly flat phase if the disorder is bounded and wea

I. A. Nekrasov, M. A. Korotin, V. I. Anisimov

Coulomb interaction between electrons on p-orbitals of oxygen atom in strongly correlated compounds is not negligible, since its value (U_p) has comparable order of magnitude with the value of Coulomb interaction on d-orbitals of transition metal atom (U_d). We investigate the effect of taking into account Coulomb correlations in oxygen p-shell in addition t

Yigal Meir

Effective-medium theory is applied to the percolation description of the metal-insulator transition in two dimensions with emphasis on the continuous connection between the zero-magnetic-field transition and the quantum Hall transition. In this model the system consists of puddles connected via saddle points, and there is loss of quantum coherence inside the

C. Fiolhais, C. Henriques, I. Sarria, J. M. Pitarke

We examine first-order perturbative results based on jellium for the surface energy of slabs of simple metals, using various local pseudopotentials (Ashcroft, Heine-Abarenkov and evanescent core). The difference between the pseudopotential and the jellium potential is averaged along the plane parallel to the surface. We compare these perturbative results wit

P. Leboeuf, A. Monastra

The grand potential $Ω$ and the response $R = - \partial Ω/\partial x$ of a phase-coherent confined noninteracting electron gas depend sensitively on chemical potential $μ$ or external parameter $x$. We compute their autocorrelation as a function of $μ$, $x$ and temperature. The result is related to the short-time dynamics of the corresponding classical syst

Ekkehard Krüger

The localized states within the Heisenberg model of magnetism should be represented by best localized Wannier functions forming a unitary transformation of the Bloch functions of the narrowest partly filled energy bands in the metals. However, as a consequence of degeneracies between the energy bands near the Fermi level, in any metal these Wannier functions

S. E. Barnes

Quantum tunneling of nano-magnets finds a natural description in terms of intermediate spin. Periodic magnetic effects correspond to a change of flux by the flux quantum $Φ_{0}$. Schrödinger cat states with different superpositions of the applied magnetic field occur. The molecular magnet Fe$_{8}$ is discussed and oscillations are predicted for Mn$_{12}$.

Malcolm P. Kennett, Claudio Chamon

We study the long time dynamics of a quantum version of the Sherrington-Kirkpatrick model. Time reparametrizations of the dynamical equations have a parallel with renormalization group transformations, and within this language the long time behaviour of this model is controlled by a reparametrization group (R$_p$G) fixed point of the classical dynamics. The

S. E. Barnes

The theory for the quantum tunneling of nano-magnets is developed within the intermediate spin framework. Periodic magnetic effects are seen to reflect that associated with a change of flux by a single flux quantum $Φ_{0}$. Essential are Schrödinger cat wave functions which involve superpositions of different magnitudes of the applied magnetic field. For sys

Aris L. Moustakas, Harold U. Baranger, Leon Balents, Anirvan M. Sengupta

Coherent wave propagation in disordered media gives rise to many fascinating phenomena as diverse as universal conductance fluctuations in mesoscopic metals and speckle patterns in light scattering. Here, the theory of electromagnetic wave propagation in diffusive media is combined with information theory to show how interference affects the information tran

Randall D. Kamien, Jonathan V. Selinger

This paper reviews the complex ordered structures induced by chirality in liquid crystals. In general, chirality favors a twist in the orientation of liquid-crystal molecules. In some cases, as in the cholesteric phase, this favored twist can be achieved without any defects. More often, the favored twist competes with applied electric or magnetic fields or w

S. B. Rutkevich

It is widely accepted that the free energy F(H) of the two-dimensional Ising model in the ferromagnetic phase T<T_c has an essential branch cut singularity at the origin H=0. The phenomenological droplet theory predicts that near the cut drawn along the negative real axis H<0, the imaginary part of the free energy per lattice site has the form Im F[exp (\pm

Alexei Vazquez

A model for growing networks is introduced, having as a main ingredient that new nodes are attached to the network through one existing node and then explore the network through the links of the visited nodes. From exact calculations of two limiting cases and numerical simulations the phase diagram of the model is obtained. In the stationary limit, large net

M. Pustilnik, L. I. Glazman

Kondo effect in the vicinity of a singlet-triplet transition in a vertical quantum dot is considered. This system is shown to map onto a special version of the two-impurity Kondo model. At any value of the control parameter, the system has a Fermi-liquid ground state. Explicit expressions for the linear conductance as a function of the control parameter and

Chun Xu, Stefi A. Baum, Christopher P. O&#39;Dea, J. M. Wrobel

We observed 17 nearby low luminosity FR I radio galaxies using the NRAO Very Long Baseline Array (VLBA) at 1.67 GHz, as part of a multi-wavelength study of a complete sample of 21 sources selected by radio flux density from the Uppsala General Catalogue of Galaxies. We detected radio emission from all 17 galaxies. At a FWHM resolution of ~ 10x4 mas, five gal

L. van Zee

The results of optical spectroscopy of two HII regions in UGCA 292 (CVn I dwA) are presented. UGCA 292 is a nearby (D=3.1 Mpc) gas-rich dwarf irregular galaxy (M_H/L_B ~ 6.9) which was first discovered in a blind HI survey. The derived oxygen abundance is the third lowest of known star-forming galaxies [12 + log(O/H) = 7.30 +/- 0.05], making UGCA 292 one of

Terry Jay Jones

Imaging polarimetry at 1.65 and 2.2 $μ$m is presented for the classic starburst galaxy M82 and the advanced merger system Cen A. Polarimetry at near IR wavelengths allows the magnetic field geometry in galaxies to be probed much deeper into dusty regions than optical polarimetry. In M82, the magnetic field throughout the nucleus has a polar geometry, presuma

Renzo Sancisi, Filippo Fraternali, Tom Oosterloo, Gustaaf van Moorsel

The results of observational studies on the vertical HI density distribution and kinematics of the disks of spiral galaxies are reported and discussed. Attention is drawn to the presence of HI emission, unknown before and here referred to as the `beard&#39;, which has anomalous structure and kinematics, different from the known cold HI disk. This component i

John M. Carpenter

We use the 2MASS Second Incremental Release Point Source Catalog to investigate the spatial distribution of young stars in the Perseus, Orion A, Orion B, and MonR2 molecular clouds. After subtracting a semi-empirical model of the field star contamination from the observed star counts, stellar surface density maps are used to identify compact clusters and any

Leonardo Tommasi, Ruben Diaz, Eliana Palazzi, Elena Pian

The polarized and total flux of the BL Lac object PKS 2155-304 were monitored intensively and simultaneously in the optical UBVRI bands with the Turin photopolarimeter at the CASLEO 2.15 m telescope during 4 campaigns in June, August, November 1998 and August 1999. The effective observation time amounted to ~47 hours. PKS 2155-304 showed a linear polarizatio

T. Venturi, R. Morganti, T. Tzioumis, J. Reynolds

In this paper we present the results of VLBI observations of six radio galaxies belonging to the 2-Jy sample. The selected objects are 3C17, PKS 0620-52, PKS 0625-35, PKS 1318-43, PKS 1333-33 and 3C317. The first is a high power radio galaxy and the remainder are low power objects. Our observations were carried out with a set of different arrays and frequenc

Filippo Fraternali, Tom Oosterloo, Renzo Sancisi, Gustaaf van Moorsel

Deep VLA HI observations of the nearby spiral galaxy NGC 2403 reveal the presence of an extended HI halo that shows slower rotation and a general inflow (about 15-25 km\s) towards the center of the galaxy.