February 2001 arXiv papers — page 3

Kazuhito Itoh, Masaaki Nakamura, Norihiro Muramoto

We show the existence of an exact ground state in certain parameter regimes of one-dimensional half-filled extended Hubbard model with site-off-diagonal interactions. In this ground state, the bond-located spin correlation exhibits a long-range order. In the case when the spin space is SU(2) symmetric, this ground state degenerates with higher spin states in

R. Desfeux, S. Bailleul, A. Da Costa, W. Prellier

Colossal magnetoresistive (CMR) La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ (LSMO) thin films have been grown under tensile strains on (100)-SrTiO$_{3}$ substrates and compressive strains on (100)-LaAlO$_{3}$ and (110)-NdGaO$_{3}$ substrates by pulsed laser deposition. Using magnetic force microscopy (MFM), a "feather-like" magnetic pattern, characteristic of film

L. Didukh, Yu. Skorenkyy, V. Hankevych, O. Kramar

In the present paper the ground state of a double orbitally degenerate model at weak intra-atomic interaction is studied using the Green functions method. Beside the diagonal matrix elements of electron-electron interactions the model includes correlated hopping integrals and inter-atomic exchange interaction. The influence of orbital degeneracy with Hund&#3

Michal Rosen-Zvi, Ido Kanter

On-line and batch learning of a perceptron in a discrete weight space, where each weight can take $2 L+1$ different values, are examined analytically and numerically. The learning algorithm is based on the training of the continuous perceptron and prediction following the clipped weights. The learning is described by a new set of order parameters, composed o

H. Potempa, L. Schweitzer

The transition from the quantum Hall state to the insulator is considered for non-interacting electrons in a two-dimensional disordered lattice model with perpendicular magnetic field. Using correlated random disorder potentials the floating up of the critical states can be observed in a similar way as in the continuum model. Thus, the peculiar behaviour of

S. Suzuki, S. Higai, K. Nakao

We study two-dimensional sigma-hole systems in boron layers by calculating the electronic structures of Mg_{1-x}Na_xB_2 and Mg_{1-x}Al_xB_2. In Mg_{1-x}Na_xB_2, it is found that the concentration of sigma holes is approximately described by (0.8 + 0.8 x) * 10^{22} cm^{-3} and the largest attainable concentration is about 1.6 * 10^{22} cm^{-3} in NaB_2. In Mg

L. I. Plimak, M. Fleischhauer, M. K. Olsen, M. J. Collett

We describe quantum-field-theoretical (QFT) techniques for mapping quantum problems onto c-number stochastic problems. This approach yields results which are identical to phase-space techniques [C.W. Gardiner, {\em Quantum Noise} (1991)] when the latter result in a Fokker-Planck equation for a corresponding pseudo-probability distribution. If phase-space tec

Pochung Chen, C. Piermarocchi, L. J. Sham

This work presents a step furthering a new perspective of proactive control of the spin-exciton dynamics in the quantum limit. Laser manipulation of spin-polarized optical excitations in a semiconductor nanodot is used to control the spin dynamics of two interacting excitons. Shaping of femtosecond laser pulses keeps the quantum operation within the decohere

Y. Ashkenazy, P. Ch. Ivanov, S. Havlin, C. -K. Peng

The cardiac interbeat (RR) increment time series can be decomposed into two sub-sequences: a magnitude series and a sign series. We show that the sign sequence, a simple binary representation of the original RR series, retains fundamental scaling properties of the original series, is robust with respect to outliers, and may provide useful information about n

T. Vogt, G. Schneider, J. A. Hriljac, G. Yang

The lattice parameters of MgB2 up to pressures of 8 GPa were determined using high-resolution x-ray powder diffraction in a diamond anvil cell. The bulk modulus, B0, was determined to be 151 +-5 GPa. Both experimental and first-principles calculations indicate nearly isotropic mechanical behavior under pressure. This small anisotropy is in contrast to the 2

Peter A. Bergbusch, Don A. VandenBerg

An improved algorithm for interpolating isochrones and isochrone population functions (IPFs), based on the scheme introduced by Bergbusch & VandenBerg (1992, APJS, 81, 163), is described. The computer programs (FORTRAN 77) and the grids of evolutionary tracks, for 17 [Fe/H] values between -2.31 and and -0.3, with three choices of [alpha/Fe] (0.0, 0.3, and 0.

A. Y. Kniazev, S. A. Pustilnik, A. V. Ugryumov, A. G. Pramsky

The study of group properties of the extremely metal-deficient gas-rich local dwarfs is very promising for the understanding the galaxy formation process at high redshifts. About 20 such objects have been picked up from the literature in the recent review by Kunth & Ostlin(2000). However part of these galaxies got low metallicity as a result of earlier obser

Charles L. Curry, Steven W. Stahler

Molecular-line observations of star-forming cloud cores indicate that they are not the flattened structures traditionally considered by theory. Rather, they are elongated, perhaps in the direction of their internal magnetic field. We are thus motivated to consider the structure and evolution of axisymmetric, magnetized clouds that start from a variety of ini

Miguel A. de Avillez, Mordecai-Mark Mac Low

Recent HI emission observations of the Southern Galactic hemisphere have revealed a mushroom-like structure extending from z=-70 to -450 pc, composed of a stem and a cap. Similar structures occur in three-dimensional simulations of a dynamic galactic disk driven by isolated and clustered supernovae. Using these simulations, we show that hot gas in the Galact

L. Testi, A. Natta, D. S. Shepherd, D. J. Wilner

We present Very Large Array observations of the intermediate mass pre-main-sequence stars UX Ori and CQ Tau at 7mm, 3.6cm, and 6cm. These stars are members of the UX Ori variability class, where the origin of optical variability is thought to derive from inhomogeneities in circumstellar disks. Both stars are detected at 7mm but not at longer wavelengths, whi

E. Hawkins, S. Maddox, E. Branchini, W. Saunders

We measure the autocorrelation function of galaxies in the IRAS Point Source Catalogue galaxy redshift (PSCz) survey and investigate its dependence on the far-infrared colour and absolute luminosity of the galaxies. We find that the PSCz survey correlation function can be modelled out to a scale of 10 h^{-1}Mpc as a power law of slope 1.30 +/- 0.04 and corre

Mallory S. E. Roberts, Roger W. Romani, Nobuyuki Kawai, Bryan M. Gaensler

We present X-ray and radio studies of sources which are brightabove 1 GeV (F_{>1GeV} > 4e-8 ph/cm^2/s. Only 11 out of ~30 of these gamma-ray sources have been identified with lower energy counterparts: 5 blazars and 6 pulsars. Three of these pulsars are surrounded by radio pulsar wind nebulae (PWN), two of which are also seen as bright, extended X-ray synchr

Giuliano Giuricin, Srdjan Samurovic, Marisa Girardi, Marino Mezzetti

We use the two-point correlation function in redshift space, $ξ(s)$, to study the clustering of the galaxies and groups of the Nearby Optical Galaxy (NOG) sample, which is a nearly all-sky, complete, magnitude-limited sample of $\sim$7000 bright and nearby optical galaxies. The correlation function of galaxies is well described by a power law, $ξ(s)=(s/s_0)^

Tyler L. Bourke, Philip C. Myers, Garry Robinson, A. R. Hyland

We present the results of a new survey of 23 molecular clouds for the Zeeman effect in OH undertaken with the ATNF Parkes 64-m radio telescope and the NRAO Green Bank 43-m radio telescope. The Zeeman effect was clearly detected in the cloud associated with the HII region RCW 38, with a field strength of 38+/-3 micro-Gauss, and possibly detected in a cloud as

Joel H. Kastner, Saeqa D. Vrtilek, Noam Soker

We report the discovery of X-ray emission from NGC 7027, a prototypical object for the study of the formation and evolution of planetary nebulae (PNs). Observations with the Advanced CCD Imaging Spectrometer (ACIS) aboard the Chandra X-ray Observatory show that the X-ray emission from NGC 7027 is extended and is bipolar in morphology. The ACIS spectrum displ

Alfredo Sandoval-Villalbazo, Ana Garcia-Perciante, LS Garcia-Colin

A generalized analysis of the local entropy production of a simple fluid is used to show that, if intrinsic angular momentum is taken into account, rotational viscosity must arise in the linear non-equilibrium regime. As a consequence, the stress tensor of dense rotating matter, such as the one present in neutron stars, posseses a significant non-vansishing

Sudip Bhattacharyya, Dipankar Bhattacharya, Arun V. Thampan

We present computed spectra, as seen by a distant observer, from the accretion disc around a rapidly rotating neutron star. Our calculations are carried out in a fully general relativistic framework, with exact treatment of rotation. We take into account the Doppler shift, gravitational redshift and light bending effects in order to compute the observed spec

M. Magliocchetti, L. Moscardini, P. Panuzzo, G. L. Granato

This paper investigates the clustering properties of SCUBA-selected galaxies in the framework of a unifying scheme relating the formation of QSOs and spheroids (Granato et al. 2000). The theoretical angular correlation function is derived for different bias functions, corresponding to different values of the ratio $M_{\rm halo}/M_{\rm sph}$ between the mass

K. S. Cheng, Y. F. Huang, T. Lu

Nearly all previous discussion on beaming effects in GRBs have assumed a conical geometry. However, more and more observations on relativistic jets in radio galaxies, active galactic nuclei, and "microquasars" in the Galaxy have shown that many of these outflows are not conical, but cylindrical, i.e., they maintain constant cross sections at large sc

Long-Long Feng, Jesus Pando, Li-Zhi Fang

The hierarchical clustering model of the cosmic mass field is examined in the context of intermittency. We show that the mass field satisfying the correlation hierarchy $ξ_n\simeq Q_n(ξ_2)^{n-1}$ is intermittent if $κ< d$, where $d$ is the dimension of the field, and $κ$ is the power-law index of the non-linear power spectrum in the discrete wavelet transfor

V. Karas, A. Martocchia, L. Subr

We have explored spectral line profiles due to spiral patterns in accretion discs around black holes. A parametrization was employed for the shape and emissivity of spiral waves, which can be produced by non-axisymmetric perturbations affecting the disc density and ionization structure. The effects of the light-travel time, energy shift, and gravitational fo

Rick Edelson, Gareth Griffiths, Alex Markowitz, Steve Sembay

The bright, strongly variable BL Lac object PKS 2155-304 was observed by XMM for two essentially uninterrupted periods of ~11 and 16 hr on 30-31 May 2000. The strongest variations occurred in the highest energy bands. After scaling for this effect, the three softest bands (0.1-1.7 keV) showed strong correlation with no measurable lag to reliable limits of $τ

Jason A. Surace, David B. Sanders

Ground-based high spatial-resolution optical and near-IR imaging at BIHK&#39; is presented for a complete sample of optically selected Palomar-Green QSOs which have infrared excesses at least as great as those of &#34;warm&#34; AGN-like ultraluminous infrared galaxies. In all cases, the host galaxies of the QSOs were detected and most have considerable two-d

Max Pettini, Alice E. Shapley, Charles C. Steidel, Jean-Gabriel Cuby

We present the first results of a spectroscopic survey of Lyman break galaxies in the near-infrared aimed at detecting the emission lines of [O II], [O III], and Hbeta from the H II regions of star forming galaxies at z = 3. From observations of 19 objects with the Keck and VLT telescopes, we reach the following main conclusions. Contrary to expectations, th

Michael Ibison, Harold E. Puthoff

It is well known that the third-order Lorentz-Dirac equation admits runaway solutions wherein the energy of the particle grows without limit, even when there is no external force. These solutions can be denied simply on physical grounds, and on the basis of careful analysis of the correspondence between classical and quantum theory. Nonetheless, one would pr

Je-An Gu, W-Y. P. Hwang

We propose a new scenario to implement spontaneous symmetry breaking in the space-time of an arbitrary dimension (D>2) by introducing the non-minimal coupling between the scalar field and the gravity. In this scenario, the usage of the familiar lambda Phi ^4 term, which is non-renormalizable for D >= 5, can be avoided altogether.

S. Kharchev, D. Lebedev, M. Semenov-Tian-Shansky

The paper deals with the analytic theory of the quantum q-deformed Toda chain; the technique used combines the methods of representation theory and the Quantum Inverse Scattering Method. The key phenomenon which is under scrutiny is the role of the modular duality concept (first discovered by L.Faddeev) in the representation theory of noncompact semisimple q

Junji Hisano, Kazuhiro Tobe

In the light of the recent muon (g_mu-2) result by the E821 experiment at the Brookhaven National Laboratory, we study the event rates of the charged lepton-flavour-violating (LFV) processes in the supersymmetric standard model (SUSY SM) with the heavy right-handed neutrinos (SUSY see-saw model). Since the left-handed sleptons get the LFV masses via the neut

U. Zeitler, J. G. S. Lok

A Comment on the Letter by S. Zelakiewicz et al., Phys. Rev. Lett. 85, 1942 (2000).

G. Dvali, S. Randjbar-Daemi, R. Tabbash

We suggest that the electroweak Higgs particles can be identified with extra-dimensional components of the gauge fields, which after compactification on a certain topologically non-trivial background become tachyonic and condense. If the tachyonic mass is a tree level effect, the natural scale of the gauge symmetry breaking is set by the inverse radius of th

Jian-Ge Zhou

The RR Page charges for the D2-, D4-, D6-brane in B fields are constructed explicitly from the equations of motion and the nonvanishing (modified) Bianchi identities by exploiting their properties --- conserved and localized. It is found that the RR Page charges are independent of the backgound B fields, which provides further evidence that the RR Page charg

E. V. Ivashkevich, N. Sh. Izmailian, Chin-Kun Hu

For the free models of statistical mechanics on torus, exact asymptotic expansions of the free energy, the internal energy and the specific heat in the vicinity of the critical point are found. It is shown that there is direct relation between the terms of the expansion and the Kronecker&#39;s double series. The latter can be expressed in terms of the ellipt

Nicolas Suaud, Marie-Bernadette Lepetit

We report {\it ab initio} calculations of the charge ordering in $α^\prime NaV_2O_5$ using large configurations interaction methods on embedded fragments. Our major result is that the $2p_y$ electrons of the bridging oxygen of the rungs present a very strong magnetic character and should thus be explicitly considered in any relevant effective model. The most

Alex Kaivarainen

This is a new book of quantum Hierarchic theory of condensed matter, general for liquids and solids, developed by this author during 20 years and its numerous applications. Computer program, based on new theory, was used for simulations of big number of physical properties of water and ice. Condensed matter is considered as a superposition of 3D standing wav

Mark Auslender, Eugene Kogan

We study ferromagnetic transition in three-dimensional double-exchange model. The influence of strong spin fluctuations on conduction electrons is described in coherent potential approximation. In the framework of thermodynamic approach we construct for the system &#34;electrons (in a disordered spin configuration) + spins&#34; the Landau functional, from th

Roberto Longo

Given an irreducible local conformal net A of von Neumann algebras on the circle and a finite-index conformal subnet B of A, we show that A is completely rational iff B is completely rational. In particular this extends a result of F. Xu for the orbifold construction. By applying previous results of Xu, many coset models turn out to be completely rational an

Lachezar Georgiev

Analyzing the effective conformal field theory for the parafermionic Hall states, corresponding to filling fractions nu_k=2+k/(kM+2), k=2,3,..., M odd, we show that the even k plateaux are expected to be more stable than their odd k neighbors. The reason is that the parafermion chiral algebra can be locally extended for k even. This reconciles the theoretica

Koshiro Suzuki, T. Watari

Effects of soft SUSY-breaking terms on inflation potentials are discussed. There exist generic constraints that must be satisfied in order not for the inflaton potential to loose its flatness. We examine explicitly the constraints in the case of a hybrid inflation model and find that the coupling constant λbetween the inflaton and the ``water-fall-direction&

Giovanni Landi, John Madore

We show that the relations which define the algebras of the quantum Euclidean planes $\b{R}^N_q$ can be expressed in terms of projections provided that the unique central element, the radial distance from the origin, is fixed. The resulting reduced algebras without center are the quantum Euclidean spheres $S^{N-1}_q$. The projections $e=e^2=e^*$ are elements

T. Falter, S. Leupold, U. Mosel

We calculate the shadowing effect in nuclear photoabsorption at low photon energies (1-3 GeV) within a multiple scattering approach. We avoid some of the high energy approximations that are usually made in simple Glauber theory like the narrow width and the eikonal approximation. We find that the main contribution to nuclear shadowing at low energies stems f

I. Loa, K. Syassen

The effect of high pressure on structural and electronic properties of the novel superconductor \MB has been calculated using the full-potential linearized augmented-plane-wave method. Despite the layered crystal structure of \MB nearly isotropic compression (bulk modulus $B_0=140.1(6)$ GPa) is found with only a 1.2% decrease of the $c/a$ ratio at 10 GPa. Th

Claudio Bonanno, Giulia Menconi

We study the logistic map $f(x)=λx(1-x)$ on the unit square at the chaos threshold. By using the methods of symbolic dynamics, the information content of an orbit of a dynamical system is defined as the Algorithmic Information Content (AIC) of a symbolic sequence. We give results for the behaviour of the AIC for the logistic map. Since the AIC is not a compu

David Bruce Wilson

We show how to combine Fourier analysis with coupling arguments to bound the mixing times of a variety of Markov chains. The mixing time is the number of steps a Markov chain takes to approach its equilibrium distribution. One application is to a class of Markov chains introduced by Luby, Randall, and Sinclair to generate random tilings of regions by lozenge

Massimo Blasone, Petr Jizba

By using the Feynman-Hibbs prescription for the evolution amplitude, we quantize the system of a damped harmonic oscillator coupled to its time-reversed image, known as Bateman&#39;s dual system. The time-dependent quantum states of such a system are constructed and discussed entirely in the framework of the classical theory. The corresponding geometric (Pan

Yue-Liang Wu, Yu-Feng Zhou

The measurement of $\sin 2 β$ is discussed within and beyond the standard model. In the presence of new physics, the angle $β$ extracted from the global fit(denoted by $β^{SM}_{fit}$) and the one extracted from $B\to J/ψK_S$ (denoted by $β_{J/ψ}$) are in general all different from the &#39;true&#39; angle $β$ which is the weak phase of CKM matrix element $V^

Italo Vecchi

A response to criticism of the author&#39;s previous paper quant-ph/0002084.

B. Militello, A. Messina, A. Napoli

A &#34;continuous measurement&#34; Quantum Zeno Effect (QZE) in the context of trapped ions is predicted. We describe the physical system and study its exact time evolution showing the appearance of Zeno Phenomena. New indicators for the occurrence of QZE in oscillatory systems are proposed and carefully discussed.

Savely G. Karshenboim

The usefulness of study of hyperfine splitting in the hydrogen atom is limited on a level of 10 ppm by our knowledge of the proton structure. One way to go beyond 10 ppm is to study a specific difference of the hyperfine structure intervals 8 Delta nu_2 - Delta nu_1. Nuclear effects for are not important this difference and it is of use to study higher-order

M. N. Achasov, B. A. Baryshev, K. I. Beloborodov, A. V. Bozhenok

The results of tests of 1'' vacuum phototriodes in a magnetic field up to 4.5 T are presented. It was found that output amplitude decreases by about 6 % per tesla in the magnetic field range from 2.0 to 4.0 T. For devices with an anode mesh pitch of 16$\mu$m, the output amplitude at 4.0 T is 30 % lower than that at zero field.

A. Andronic, H. Appelshaeuser, C. Blume, P. Braun-Munzinger

A Transition Radiation Detector (TRD) has been designed to improve the electron identification and trigger capability of the ALICE experiment at the Large Hadron Collider (LHC) at CERN. We present results from tests of a prototype of the TRD concerning pion rejection for different methods of analysis over a momentum range from 0.7 to 2 GeV/c. We investigate

B. Borderie

Vaporized and multifragmenting sources produced in heavy ion collisions at intermediate energies are good candidates to investigate the phase diagram of nuclear matter. The properties of highly excited nuclear sources which undergo a simultaneous disassembly into particles are found to sign the presence of a gas phase. For heavy nuclear sources produced in t

INDRA Collaboration, G. Tabacaru, B. Borderie, M. F. Rivet

Multifragmentation of fused systems was observed for central collisions between 32 AMeV 129Xe and Sn, and 36 AMeV 155Gd and U. Previous extensive comparisons between the two systems led to the hypothesis of spinodal decomposition of finite systems as the origin of multifragmentation for incident energies around 30 AMeV. New results on velocity and charge cor

Paul B. Slater

For the eight-dimensional Riemannian manifold comprised by the three-level quantum systems endowed with the Bures metric, we numerically approximate the integrals over the manifold of several functions of the curvature and of its (anti-)self-dual parts. The motivation for pursuing this research is to elaborate upon the findings of Dittmann in his paper, &#34

T. A. Larsson

The recently constructed Fock representations of $N$-dimensional diffeomorphism and current algebras are reformulated in terms of one-dimensional currents, satisfying Virasoro and affine Kac-Moody algebras.

Boris Apanasov

We describe relations between hyperbolic geometry and codimension two knots or, more exactly, between varieties of conjugacy classes of discrete faithful representations of the fundamental groups of hyperbolic n-manifolds M into $\operatorname{SO}^{\circ} (n+2,1)$ and (n-1)-dimensional knots in the (n+1)-sphere. This approach allows us to discover a phenomen

Mircea Mustata

Let X be a smooth variety and Y a closed subscheme of X. By comparing motivic integrals on X and on a log resolution of (X,Y), we prove the following formula for the log canonical threshold of (X,Y): c(X,Y)=dim X-sup_m{(dim Y_m}/(m+1)}, where Y_m is the mth jet scheme of Y. We show how this formula can be used to study the log canonical threshold. In particu

Balint Virag

Consider the time T_oz when the random walk on a weighted graph started at the vertex o first hits the vertex set z. We present lower bounds for T_oz in terms of the volume of z and the graph distance between o and z. The bounds are for expected value and large deviations, and are asymptotically sharp. We deduce rate of escape results for random walks on inf

Balint Virag

This paper studies anchored expansion, a non-uniform version of the strong isoperimetric inequality. We show that every graph with i-anchored expansion contains a subgraph with isoperimetric (Cheeger) constant at least i. We prove a conjecture by Benjamini, Lyons and Schramm (1999) that in such graphs the random walk escapes with a positive lim inf speed. We

Th. Gallay, C. E. Wayne

We use the vorticity formulation to study the long-time behavior of solutions to the Navier-Stokes equation on R^3. We assume that the initial vorticity is small and decays algebraically at infinity. After introducing self-similar variables, we compute the long-time asymptotics of the rescaled vorticity equation up to second order. Each term in the asymptoti

Th. Gallay, C. E. Wayne

We construct finite-dimensional invariant manifolds in the phase space of the Navier-Stokes equation on R^2 and show that these manifolds control the long-time behavior of the solutions. This gives geometric insight into the existing results on the asymptotics of such solutions and also allows one to extend those results in a number of ways.

Alberto S. Cattaneo, Giovanni Felder

We review and extend the Alexandrov-Kontsevich-Schwarz-Zaboronsky construction of solutions of the Batalin-Vilkovisky classical master equation. In particular, we study the case of sigma models on manifolds with boundary. We show that a special case of this construction yields the Batalin-Vilkovisky action functional of the Poisson sigma model on a disk. As

Anna Erschler-Dyubina

In this paper we consider finitary symmetric random walks on groups. We construct new possible asymptotics for the drift. We show that the drift can be very close to linear ant yet sublinear. We also give estimates for entropy growth of these random walks. In particular, we prove that there exist infinitely many asymptotics of entropy.

C. I. Lazaroiu

This is a short nontechnical note summarizing the motivation and results of my recent work on D-brane categories. I also give a brief outline of how this framework can be applied to study the dynamics of topological D-branes and why this has a bearing on the homological mirror symmetry conjecture. This note can be read without any knowledge of category theor

Albert Schwarz

We discuss instantons on noncommutative four-dimensional Euclidean space. In commutative case one can consider instantons directly on Euclidean space, then we should restrict ourselves to the gauge fields that are gauge equivalent to the trivial field at infinity. However, technically it is more convenient to work on four-dimensional sphere. We will show tha

V. P. Nair, A. P. Polychronakos

We show that the coefficient of the three-dimensional Chern-Simons action on the noncommutative plane must be quantized. Similar considerations apply in other dimensions as well.

Minu Joy, V. C. Kuriakose

Condsidering a massive self-interacting phi ^6 scalar field coupled arbitrarily to a (2+1) dimensional Bianchi type-I spacetime, we evaluate the one-loop effective potential. It is found that phi ^6 potential can be regularized in (2+1) dimensional curved spacetime. A finite expression for the energy-momentum tensor is obtained for this model. Evaluating the

Satoshi Yamaguchi

We investigate a noncompact Gepner model, which is composed of a number of SL(2,R)/U(1) Kazama-Suzuki models and N=2 minimal models. The SL(2,R)/U(1) Kazama-Suzuki model contains the discrete series among the SL(2,R) unitary representations as well as the continuous series. We claim that the discrete series contain the vanishing cohomology and the vanishing

G. Sardanashvily

We show that cohomology of the variational complex in field-antifield BRST theory on an arbitrary manifold is equal to the de Rham cohomology of this manifold.

S. S. Gubser, C. P. Herzog, I. R. Klebanov, A. A. Tseytlin

The supergravity dual of $N$ regular and $M$ fractional D3-branes on the conifold has a naked singularity in the infrared. Supersymmetric resolution of this singularity requires deforming the conifold: this is the supergravity dual of chiral symmetry breaking. Buchel suggested that at sufficiently high temperature there is no need to deform the conifold: the

David Berenstein, Robert G. Leigh

We discuss non-commutative field theories in coordinate space. To do so we introduce pseudo-localized operators that represent interesting position dependent (gauge invariant) observables. The formalism may be applied to arbitrary field theories, with or without supersymmetry. The formalism has a number of intuitive advantages. First it makes clear the appea

H. V. Klapdor-Kleingrothaus

Double beta decay is indispensable to solve the question of the neutrino mass matrix together with $\nu$ oscillation experiments. The most sensitive experiment since eight years - the Heidelberg-Moscow experiment in Gran-Sasso - already now, with the experimental limit of $<m_\nu > < 0.26$ eV excludes degenerate $\nu$ mass scenarios allowing neutrinos as hot

S. Heinemeyer

Recent electroweak two-loop corrections in the Minimal Supersymmetric Standard Model (MSSM) are reviewed. They have been obtained with the help of the programs FeynArts and TwoCalc, making use of the recently completed MSSM model file for FeynArts. Short examples of how to use the two codes together with the analytic result for the O(Gf^2 m_t^4) corrections

S. Heinemeyer, G. Weiglein

The leading electroweak MSSM two-loop corrections to the $ρ$-parameter are calculated. They are obtained by evaluating the two-loop self-energies of the Z and the W boson at O(Gf^2 m_t^4) in the limit of heavy scalar quarks. A very compact expression is derived, depending on the ratio of the CP-odd Higgs boson mass, M_A, and the top quark mass, m_t. Expressi

Andrzej J. Buras, Sebastian Jager, Joerg Urban

We present analytic formulae for the QCD renormalization group factors relating the Wilson coefficients C_i(mu_t) and C_i(mu), with mu_t = O(m_t) and mu < mu_t, of the Delta F=2 dimension six four-quark operators Q_i in the Standard Model and in all of its extensions. Analogous analytic formulae for the QCD factors relating the matrix elements <Q_i(2 GeV)> a

V. M. Braun, G. P. Korchemsky, A. N. Manashov

We perform an extensive study of the scale dependence of flavor-singlet contributions to the structure function g_2(x,Q^2) in polarized deep-inelastic scattering. We find that the mixing between quark-antiquark-gluon and three-gluon twist-3 operators only involves the three-gluon operator with the lowest anomalous dimension and is weak in other cases. This m

B. A. Arbuzov

Theory with $SU(2)\times U(1)$ gauge invariant electroweak Lagrangian describing standard interaction of massless quark doublet without elementary scalar Higgs sector is considered. We show in the main order of $1/N_c$ expansion, that there exists a solution, which breaks initial symmetry and is accompanied by an appearance of zero mass composite scalar doub

A. H. Hoang

Recent results for charm quark mass effects in perturbative bottom quark mass determinations from $Υ$ mesons are reviewed. The connection between the behavior of light quark mass corrections and the infrared sensitivity of some bottom quark mass definitions is examined in some detail.

T. Csorgo, M. Gyulassy, D. Kharzeev

We propose that femto scale QCD analogs of Fullerene type excitations may exist with ``magic numbers&#39;&#39; 8,24,48, and 120. These ``J-balls&#39;&#39; are the most symmetrical closed networks of gluonic baryon junctions and anti-junctions with zero net baryon number. CP odd J-Moebii and other femto-tubes and tori gluonic structures may also exist. We est

NuTeV Collaboration, M. Goncharov, P. Spentzouris

We present measurements of the semi-inclusive cross-sections for muon neutrino and muon antineutrino-nucleon deep inelastic scattering interactions with two oppositely charged muons in the final state. These events dominantly arise from production of a charm quark during the scattering process. The measurement was obtained from the analysis of 5102 muon neut

A. Miyazaki

The Machian cosmological solution satisfying $ϕ=O(ρ/ω)$ is discussed for the homogeneous and isotropic universe with a perfect fluid (with negative pressure) in the generalized scalar-tensor theory of gravitation. We propose $ω(ϕ)=η/(ξ-2)$ for the coupling function in the Machian point of view. The parameter $ξ$ varies in time very slowly from $ξ=0$ to $ξ=2$

A. Lewis Licht

The effect of the expanding universe on planetary motion is considered to first order in the Hubble constant H. Orbital elements are shown to be unaffected, but there is a small change in the connection between planetary proper time and coordinate time. This can produce an apparent anomalous acceleration in velocities inferred from echo-ranging, but the effe

Chris Kimble, Kevin McLoughlin

This paper identifies three categories of model: the Technology Impact Model; the Social Impact Model and the Integrationist Model, which imply different views of the &#34;impact&#34; of Information Technology on work organisation. These models are used to structure data from case studies conducted by the authors to explore the implications of the use of com

Chris Kimble, Paul Hildreth, Peter Wright

With the current trends towards downsizing, outsourcing and globalisation, modern organisations are reducing the numbers of people they employ. In addition, organisations now have to cope with the increasing internationalisation of business forcing collaboration and knowledge sharing across time and distance simultaneously. There is a need for new ways of th

A. Slepoy, R. R. P. Singh, F. Pázmándi, R. N. Kulkarni

We simulate a two-dimensional, lattice based, protein-level statistical mechanical model for prion diseases (e.g., Mad Cow disease) with concommitant prion protein misfolding and aggregation. Our simulations lead us to the hypothesis that the observed broad incubation time distribution in epidemiological data reflect fluctuation dominated growth seeded by a

Ricardo Garcia-Pelayo

The purpose of this work is to find the time dependent distributions of directions and positions of a particle that undergoes multiple elastic scattering. The angular cross section is given and the scatterers are randomly placed. The distribution of directions is found. As for the second distribution we find an exact expression for isotropic cross section in

Tatsuya Nakajima

The spectral functions of the pseudospin correlation functions in the bilayer quantum Hall system at ν=1 are investigated numerically, where the pseudospin describes the layer degrees of freedom. In the pseudospin-ferromagnetic phase, the lowest-energy excitation branch is closely connected with the ground state through the fluctuations of pseudospin S_y and

J. F. Zasadzinski, L. Ozyuzer, N. Miyakawa, K. E. Gray

New break-junction tunneling data are reported in Bi2Sr2CaCu2O(8+delta) over a wide range of hole concentration from underdoped (Tc = 74 K) to optimal doped (Tc = 95 K) to overdoped (Tc = 48 K). The conductances exhibit sharp dips at a voltage, Omega/e, measured with respect to the superconducting gap. Clear trends are found such that the dip strength is max

R. S. Markiewicz

The Jahn-Teller system E x b_1 + b_2 has a particular degeneracy, where the vibronic potential has an elliptical minimum. In the general case where the ellipse does not reduce to a circle, the classical motion in the potential is chaotic, tending to trapping near one of the extrema of the ellipse. In the quantum problem, the motion consists of correlated tun

P. E. Jönsson, J. L. Garcia-Palacios

The relaxation time of weakly interacting classical spins is calculated by introducing the averages of the local dipolar field, obtained by thermodynamic perturbation theory, in a rigorous expression for the single-spin thermoactivation rate in a weak but arbitrarily oriented field. At low temperatures the non-trivial dependence of the superparamagnetic bloc

Alexander P. Itin

We determined the eigenstates of a single electron in a parabolic anisotropic 2D quantum dot in a magnetic field. Using obtained expressions for these eigenstates, we study the spin coupling J between two electrons located in two laterally coupled anisotropic quantum dots (QD). The exhange coupling J is calculated using the Heitler-London and Hund-Mulliken a

U. S. Schwarz, G. Gompper

Inverse bicontinuous cubic phases are ubiquitous in lipid-water mixtures and consist of a lipid bilayer forming a cubic minimal surface, thereby dividing space into two cubic networks of water channels. For small hydrocarbon chain lengths, the monolayers can be modeled as parallel surfaces to a minimal midsurface. The bending energy of the cubic phases is de

Manfred Sigrist, Hartmut Monien

We model the 3K-phase of Sr2RuO4 with Ru-metal inclusion as interface state with locally enhanced transition temperatures. The resulting 3K-phase must have a different pairing symmetry than the bulk phase of Sr2RuO4, because the symmetry at the interface is lower than in the bulk. It is invariant under time reversal and a second transition, in general, above

Sorcha B. Healy, Claudia Filippi, P. Kratzer, E. Penev

Recent low-temperature scanning tunneling experiments have challenged the generally accepted picture of buckled silicon dimers as the ground state reconstruction of the Si(100) surface. Together with the symmetric dimer model of the surface suggested by quantum chemistry calculations on small clusters, these findings question our general understanding of ele

Stefano Zapperi, Andre A. Moreira, Jose S. Andrade

We investigate flux front penetration in a disordered type II superconductor by molecular dynamics (MD) simulations of interacting vortices and find scaling laws for the front position and the density profile. The scaling can be understood performing a coarse graining of the system and writing a disordered non-linear diffusion equation. Integrating numerical

V. G. Koukhar, N. A. Pertsev, R. Waser

A Landau-Ginsburg-Devonshire-type nonlinear phenomenological theory is presented, which enables the thermodynamic description of dense laminar polydomain states in epitaxial ferroelectric thin films. The theory explicitly takes into account the mechanical substrate effect on the polarizations and lattice strains in dissimilar elastic domains (twins). Numeric