April 1999 arXiv papers — page 14

Noboru Kawamoto

Non-standard overview on the possible formulation towards a unified model on the lattice is presented. It is based on the generalized gauge theory which is formulated by differential forms and thus expected to fit in a simplicial manifold. We first review suggestive known results towards this direction. As a small step of concrete realization of the program,

A. Connes, D. Kreimer

We discuss the prominence of Hopf algebras in recent progress in Quantum Field Theory. In particular, we will consider the Hopf algebra of renormalization, whose antipode turned out to be the key to a conceptual understanding of the subtraction procedure. We shall then describe several occurences of this or closely related Hopf algebras in other mathematical

M. Chaichian, A. Demichev, P. Presnajder

We study properties of a scalar quantum field theory on two-dimensional noncommutative space-times. Contrary to the common belief that noncommutativity of space-time would be a key to remove the ultraviolet divergences, we show that field theories on a noncommutative plane with the most natural Heisenberg-like commutation relations among coordinates or even

L. Burakovsky

We present a new generalized string model for Regge trajectories J=J(E^2), where J and E are the orbital momentum and energy of the string, respectively. We demonstrate that this model is not to produce linear Regge trajectories, in contrast to the standard Nambu-Goto string, but generally nonlinear trajectories, which in many cases can be given in analytic

Matthias Neubert

Measurements of the rates for the hadronic decays B^+- -> pi K along with the CP-averaged B^+- -> pi^+- pi^0 branching ratio can be used to bound and extract the weak phase gamma=-arg(V_ub). Using preliminary CLEO data, we obtain the bounds |gamma|>93 degrees at 1 sigma, and |gamma|>71 degrees at 90 % confidence level.

D. de Florian, S. Frixione

We present a computation of one- and two-jet cross sections in polarized photon-hadron collisions, which is accurate to next-to-leading order in QCD. Our results can be used to compute photoproduction cross sections in electron-proton scattering. To this purpose, we investigate the structure of the polarized Weizsaecker-Williams function, where we include a

Saurabh D. Rindani, Michael M. Tung

The effect of anomalous chromomagnetic (mu) and chromoelectric couplings (d) of the gluon to the top quark are considered in e+ e- --> t tbar, with unpolarized and longitudinally polarized electron beams. The total cross section, as well as t and tbar polarizations are calculated to order alpha_s in the presence of the anomalous couplings. One of the two lin

R. G. Roberts

Evolution of the parton densities at NLO in $α_S$ using $\tilde W^2 = Q^2 (1-z)/z$ instead of the usual $Q^2$ for the scale of the running coupling $α_S$ is investigated. While this renormalisation scale change was originally proposed as the relevant one for $x \to 1$, we explore the consequences for all $x$ with this choice. While it leads to no improvement

S. M. Bilenky, C. Giunti, W. Grimus, T. Schwetz

It is shown that the Super-Kamiokande atmospheric up--down asymmetry, together with the results of all other neutrino oscillation experiments, allows to constraint the possible spectra of four massive neutrinos. The two schemes with two pairs of neutrinos with close masses separated by a gap of about 1 eV are favored by the data.

M. Bastero-Gil, S. F. King, J. Sanderson

We study preheating in a general class of supersymmetric hybrid inflation model. Supersymmetry leads to only one coupling constant in the potential and thus only one natural frequency of oscillation for the homogeneous fields, whose classical evolution consequently differs from that of a general (non-supersymmetric) hybrid model. We emphasise the importance

A. Kirk, the WA102 Collaboration

A partial wave analysis of the centrally produced KK and pipi systems shows that the fJ(1710) has J = 0. In addition, a study of central meson production as a function of the difference in transverse momentum (dPT) of the exchanged particles shows that undisputed qqbar mesons are suppressed at small dPT whereas the glueball candidates are enhanced and that t

Robert Fleischer

The determination of the angle $γ$ of the unitarity triangle of the CKM matrix is a challenge for the $B$-factories. In this context, $B\toπK$ decays received a lot of attention, providing various interesting ways to constrain and determine $γ$. These strategies are briefly reviewed, and their virtues and weaknesses are compared with one another.

Ph. Boucaud, C. P. Korthals Altes

At temperatures well above the transition, QCD admits a thermally reduced version in 3D, which reproduces the long distance physics. We analyze the phase diagram, point out the relevance of Z(3) symmetry in the location of the transition and suggest a way out to reconcile this with the data. Related to this symmetry is the existence of an observable, the Z(N

NA49 collaboration, H. Appelshauser

We present first data on event-by-event fluctuations in the average transverse momentum of charged particles produced in Pb+Pb collisions at the CERN SPS. This measurement provides previously unavailable information allowing sensitive tests of microscopic and thermodynamic collision models and to search for fluctuations expected to occur in the vicinity of t

The OPAL Collaboration, G. Abbiendi et al

We present a test of the flavour independence of the strong coupling constant for charm and bottom quarks with respect to light (uds) quarks, based on a hadronic event sample obtained with the OPAL detector at LEP. Five observables related to global event shapes were used to measure alpha_s in three flavour tagged samples (uds, c and b). The event shape dist

Yakov Itin

The variation procedure on a teleparallel manifold is studied. The main problem is the non-commutativity of the variation with the Hodge dual map. We establish certain useful formulas for variations and restate the master formula due to Hehl and his collaborates. Our approach is different and sometimes easier for applications. By introducing the technique of

Carlo Rovelli

We explore the relation between noncommutative geometry, in the spectral triple formulation, and quantum mechanics. To this aim, we consider a dynamical theory of a noncommutative geometry defined by a spectral triple, and study its quantization. In particular, we consider a simple model based on a finite dimensional spectral triple (A, H, D), which mimics c

S. Banerjee, M. Fasnacht, S. Garoff, M. Widom

Ferrofluids are strongly paramagnetic liquids. We study the behavior of ferrofluid droplets confined between two parallel plates with a weak applied field parallel to the plates. The droplets elongate under the applied field to reduce their demagnetizing energy and reach an equilibrium shape where the magnetic forces balance against the surface tension. This

H. Noh, S. Zelakiewicz, T. J. Gramila, L. N. Pfeiffer

Experiments studying phonon mediated drag in the double layer two dimensional electron gas system are reported. Detailed measurements of the dependence of drag on temperature, layer spacing, density ratio, and matched density are discussed. Comparisons are made to theoretical results [M. C. Bonsager et al., Phys. Rev. B 57, 7085 (1998)] which propose the exi

M. A. R. de Cara, O. Pla, F. Guinea

The minority model was introduced to study the competition between agents with limited information. It has the remarkable feature that, as the amount of information available increases, the collective gain made by the agents is reduced. This crowd effect arises from the fact that only a minority can profit at each moment, while all agents make their choices

F. Zuo, J. S. Brooks, Ross H. McKenzie, J. A. Schlueter

We report detailed measurements of the interlayer magnetoresistance of the layered organic superconductor $κ-(BEDT-TTF)_2Cu(SCN)_2$ for temperatures down to 0.5 K and fields up to 30 tesla. The upper critical field is determined from the resistive transition for a wide range of temperatures and field directions. For magnetic fields parallel to the layers, th

A. Gammal, T. Frederico, L. Tomio, Ph. Chomaz

We study the effects of a repulsive three-body interaction on a system of trapped ultra-cold atoms in a Bose-Einstein condensed state. The corresponding $s-$wave non-linear Schrödinger equation is solved numerically and also by a variational approach. A first-order liquid-gas phase transition is observed for the condensed state up to a critical strength of t

P. S. Cornaglia, C. A. Balseiro

We study the solid-liquid transition of a model of pancake vortices in laminar superconductors using a density functional theory of freezing. The physical properties of the system along the melting line are discussed in detail. We show that there is a very good agreement with experimental data in the shape and position of the first order transition in the ph

A. Aharony, O. Entin-Wohlman, Y. Imry

We present a general scheme for finding the exact eigenstates of two electrons, with on-site repulsive potentials U_i, on I impurities in a macroscopic crystal. The model describes impurities in doped semiconductors and artificial molecules in quantum dots. For quantum dots, the energy cost for adding two electrons is bounded by the single-electron spectrum,

L. De Maria, M. Springborg

The electronic structure of a single monatomic gold wire is presented for the first time. It has been obtained with state-of-the-art ab-initio full-potential density-functional (DFT) LMTO (linearized muffin-tin orbital) calculations taking into account relativistic effects. For stretched structures in the experimentally accessible range the conduction band i

N. Vandewalle, R. D'hulst

Sandpiles have become paradigmatic systems for granular flow studies in statistical physics. New directions of investigations are discussed here. Rather than varying the nature of the pile (sand, salt, rice,..) we have investigated changes in the boundary conditions. We have investigated experimentally and numerically sandpile structures on bases having a fr

David H. Cobden, Jesper Nygard, Marc Bockrath, Paul L. McEuen

We report measurements of the temperature and gate voltage dependence for individual bundles (ropes) of single-walled nanotubes. When the conductance is less than about e^2/h at room temperature, it is found to decrease as an approximate power law of temperature down to the region where Coulomb blockade sets in. The power-law exponents are consistent with th

F. F. Assaad

The 2D half-filled Kondo lattice model with exchange J and nearest neighbor hopping t is considered. It is shown that this model belongs to a class of Hamiltonians for which zero-temperature auxiliary field Monte Carlo methods may be efficiently applied. We compute the staggered moment, spin and quasiparticle gaps on lattice sizes up to 12 X 12. The competit

Markus Porto, Shlomo Havlin, H. Eduardo Roman, Armin Bunde

We consider the mean distribution functions Phi(r|l), Phi(B)(r|l), and Phi(S)(r|l), giving the probability that two sites on the incipient percolation cluster, on its backbone and on its skeleton, respectively, connected by a shortest path of length l are separated by an Euclidean distance r. Following a scaling argument due to de Gennes for self-avoiding wa

Nehemia Schwartz, Alexander L. Nazaryev, Shlomo Havlin

We apply the Dijkstra algorithm to generate optimal paths between two given sites on a lattice representing a disordered energy landscape. We study the geometrical and energetic scaling properties of the optimal path where the energies are taken from a uniform distribution. Our numerical results for both two and three dimensions suggest that the optimal path

M. Bisani, W. Selke

The probability distribution p(l) of an atom to return to a step at distance l from the detachment site, with a random walk in between, is exactly enumerated. In particular, we study the dependence of p(l) on step roughness, presence of other reflecting or absorbing steps, interaction between steps and diffusing atom, as well as concentration of defects on t

C. P. Moca, I. Tifrea, M. Crisan

We showed that an electronic system with weak disorder considered in the finite-charge infinite U Hubbard model can present a non-Fermi behavior. The imaginary pert of the self-energy has been calculated and a linear temperature dependence was obtained. This result is in agreement with the non-Fermi behavior observed at the insulator-metal crossover in La_{2

H. J. Lee, J. H. Jung, Y. S. Lee, J. S. Ahn

We investigated temperature dependent optical conductivity spectra of Nd0.7Sr0.3MnO3 single crystal. We found that polishing and surface scattering effects on the Nd0.7Sr0.3MnO3 crystal surfaces could significantly distort the optical responses, especially in the mid-infrared region. However, oxygen annealing and gold normalization processes seemed to remedy

Anusha Hazareesing, Jean-Philippe Bouchaud

We reconsider the problem of the static thermal roughening of an elastic manifold at the critical dimension $d=2$ in a periodic potential, using a perturbative Functional Renormalization Group approach. Our aim is to describe the effective potential seen by the manifold below the roughening temperature on large length scales. We obtain analytically a flow eq

Tim Scheffler, Dietrich E. Wolf

The dissipation rate due to inelastic collisions between equally charged, insulating particles in a dilute granular medium is calculated. It is equal to the known dissipation rate for uncharged granular media multiplied by a Boltzmann-like factor, that originates from Coulomb interactions. We include particle correlations by introducing an effective potentia

D. Mentrup, J. Schnack, Marshall Luban

Analytical solutions for the time-dependent autocorrelation function of the classical and quantum mechanical spin dimer with arbitrary spin are presented and compared. For large spin quantum numbers or high temperature the classical and the quantum dimer become more and more similar, yet with the major difference that the quantum autocorrelation function is

M. Bocquet, Th. Jolicoeur

We generalize the nonlinear sigma model treatment of quantum spin chains to cases including ferromagnetic bonds. When these bonds are strong enough, the classical ground state is no longer the standard Neel order and we present an extension of the known formalism to deal with this situation. We study the alternating ferromagnetic-antiferromagnetic spin chain

N. Markovic, C. Christiansen, A. M. Mack, W. H. Huber

The superconductor-insulator transition of ultrathin films of bismuth, grown on liquid helium cooled substrates, has been studied. The transition was tuned by changing both film thickness and perpendicular magnetic field. Assuming that the transition is controlled by a T=0 critical point, a finite size scaling analysis was carried out to determine the correl

L. Srinivasa Mohan, Prabhu R. Nott, K. Kesava Rao

A rigid-plastic Cosserat model has been used to study dense, fully developed flow of granular materials through a vertical channel. Frictional models based on the classical continuum do not predict the occurrence of shear layers, at variance with experimental observations. This feature has been attributed to the absence of a material length scale in their co

A. L. Chudnovskiy, S. E. Ulloa

A two-layer system coupled via tunneling and with different carrier masses in each layer is investigated in the integer quantum Hall regime. Striking deviations of the one-layer Hall conductivity from the usual quantization are found, if resonance between Landau levels of different layers is achieved. The appearance of negative jumps in the Hall conductivity

Jan Naudts

In the case of a system with an unbounded hamiltonian the entropic index q of non-extensive thermodynamics has an upperbound q_c>1 beyond which the formalism becomes meaningless. The expression 1/(q_c-1) is the dimension of the state space (i.e. the manifold of density matrices) in the context of non-commutative geometry. For q=q_c an ultraviolet cutoff E< E

Andreas Schmitz, Thomas Schreiber

Standard tests for nonlinearity reject the null hypothesis of a Gaussian linear process whenever the data is non-stationary. Thus, they are not appropriate to distinguish nonlinearity from non-stationarity. We address the problem of generating proper surrogate data corresponding to the null hypothesis of an ARMA process with slowly varying coefficients.

Kavan U. Ratnatunga, Richard E. Griffiths, Eric J. Ostrander

Quantitative morphological and structural parameters are estimated for galaxies detected in HST observations of WFPC2 survey fields. A modeling approach based on maximum likelihood has been developed for two-dimensional decomposition of faint under-sampled galaxy images into components of disk and bulge morphology. Decomposition can be achieved for images do

P. Helbig, D. R. Marlow, R. Quast, P. N. Wilkinson

We present constraints on the cosmological constant $λ_{0}$ from gravitational lensing statistics of the Jodrell Bank-VLA Astrometric Survey (JVAS). Although this is the largest gravitational lens survey which has been analysed, cosmological constraints are only comparable to those from optical surveys. This is due to the fact that the median source redshift

Ralf Quast, Phillip Helbig

We reanalyse optical gravitational lens surveys from the literature in order to determine relative probabilities in the $λ_{0}$-$Ω_{0}$ plane, using a softened singular isothermal sphere lens model. In addition, we examine a portion of the $λ_{0}$-$Ω_{0}$ plane which includes all viable cosmological models; this is vital for comparison with other cosmologica

Nagayoshi Ohashi, Siow Wang Lee, David J. Wilner, Masahiko Hayashi

We have carried out observations of the starless core L1544 in the CCS (J_N=3_2-2_1) line at 9 millimeters wavelength using the BIMA array. The maps show an elongated condensation, 0.15 x 0.045 pc in size, with stronger emission at the edges. The appearance is consistent with a flattened, ringlike structure viewed at high inclination to the line of sight. Th

Ue-Li Pen

We present a fitting formula for the luminosity and angular diameter distances in cosmological models with pressureless matter, a cosmological constant and zero spatial curvature. The formula has a relative error of less than 0.4% for 0.2<Ω_0<1 for any redshift, and a global relative error of less than 4% for any choice of parameters.

Ue-Li Pen

I discuss approaches to optimally remove noise from images. A generalization of Wiener filtering to Non-Gaussian distributions and wavelets is described, as well as an approach to measure the errors in the reconstructed images. We argue that the wavelet basis is highly advantageous over either Fourier or real space analysis if the data is intermittent in nat

L. Nicastro, L. Amati, L. A. Antonelli, E. Costa

Over a total of 20 gamma-ray bursts localized with arcmin accuracies, GRB980519 represents the 13th detected by the BeppoSAX Wide Field Cameras. An X-ray TOO observation performed by the BeppoSAX Narrow Field Instruments, starting about 9.5 hours after the high energy event, revealed X-ray afterglow emission in the 0.1--10 keV energy range. The flux decay wa

Jerome Martin, Alain Riazuelo, Mairi Sakellariadou

In the context of inflation, non-vacuum initial states for cosmological perturbations that possess a built in scale are studied. It is demonstrated that this assumption leads to a falsifiable class of models. The question of whether they lead to conflicts with the available observations is addressed. For this purpose, the power spectrum of the Bardeen potent

A. D. Kaminker, P. Haensel, D. G. Yakovlev

We calculate the neutrino energy emission rate due to singlet-state pairing of protons in the neutron star cores taking into account the relativistic correction to the non-relativistic rate. The non-relativistic rate is numerically small, and the relativistic correction appears to be about 10 -- 50 times larger. It plays thus the leading role, reducing great

T. Kifune

We postulate in the present paper that the energy-momentum relation is modified for very high energy particles to violate Lorentz invariance and the speed of photon is changed from the light velocity c. The violation effect is amplified, in a sensitive way to detection, through the modified kinematical constraints on the conservation of energy and momentum,

S. V. Zharikov, V. V. Sokolov

The observations with the SAO-RAS 6-m telescope in July-August 1998 show that the GRB970508 optical remnant has varied very little since November 1997. We can conclude that we observe a proper host galaxy without the GRB optical remnant. The fitting results of the light curve of the GRB remnant plus the host galaxy until about 400 days after the primary even

Andreas Burkert, Joseph Silk

The structure of dark matter halos as predicted from cosmological models is discussed and compared with observed rotation curves of dark matter-dominated dwarf galaxies. The theoretical models predict that dark matter halos represent a one-parameter family with a universal density profile. Observations of dark matter-dominated rotation curves indeed confirm

Michael R. Merrifield, Konrad Kuijken

It has been suggested that the boxy and peanut-shaped bulges found in some edge-on galaxies are galactic bars viewed from the side. We investigate this hypothesis by presenting emission-line spectra for a sample of 10 edge-on galaxies that display a variety of bulge morphologies. To avoid potential biases in the classification of this morphology, we use an o

L. S. Pilyugin

A remarkably small scatter in the N/O ratios for the HII regions in low-metallicity blue compact galaxies (BCG) has been found recently. It lead to the conclusion that N and O are both produced by massive stars. Conversely, the N/Si ratios in damped Lya absorbers (DLA) show a large scatter. This result provides support for the time-delay model of nitrogen pr

Christopher A. Metzler, Martin White, Michael Norman, Chris Loken

Hierarchical theories of structure formation predict that clusters of galaxies should be embedded in a web like structure, with filaments emanating from them to large distances. The amount of mass contained within such filaments near a cluster can be comparable to the collapsed mass of the cluster itself. Diffuse infalling material also contains a large amou

K. M. Leighly, J. P. Halpern, H. Awaki, M. Cappi

Scanning and pointed RXTE observations of the nearby Seyfert 2 galaxy NGC 6300 reveal that it is a source of hard X-ray continuum and large equivalent width Fe K$α$ emission. These properties are characteristic of Compton-reflection dominated Seyfert 2 galaxies. The continuum can be modeled as Compton-reflection; subsolar iron abundance is required and a hig

Charles Hoopes, Rene Walterbos, Richard Rand

(Abridged) We present H-alpha images of five edge-on galaxies: NGC 891, NGC 4631, NGC 4244, NGC 3003, and UGC 9242. We also analyze [SII] 6717+6731A and [OIII] 5007A images of NGC 4631. We analyze the ionized gas content, with particular attention to the diffuse ionized gas (DIG). The DIG layer in NGC 891 is traced out to at least 5 kpc from the midplane, co

Wayne Hu

Upcoming weak lensing surveys on wide fields will provide the opportunity to reconstruct the structure along the line of sight tomographically by employing photometric redshift information about the source distribution. We define power-spectrum statistics, including cross correlation between redshift bins, quantify the improvement that redshift information c

David F. Crawford

The reported anomalous acceleration of the Pioneer 10 spacecraft of -8.5X10^{-10} m/s^2 (i.e. towards the sun) can be explained by a gravitational interaction on the S-band signals traveling between Pioneer 10 and the earth. The effect of this gravitational interaction is a frequency shift that is proportional to the distance and the square root of the densi

Z. Rudy, W. Cassing, L. Jarczyk, B. Kamys

It is shown that the mass dependence of the $Λ$-lifetime in heavy hypernuclei is sensitive to the ratio of neutron-induced to proton-induced non-mesonic decay rates R_n/R_p. A comparison of the experimental mass dependence of the lifetimes with the calculated ones for different values of R_n/R_p leads to the conclusion that this ratio is larger than 2 on the

Fran De Aquino

There is an electromagnetic factor of correlation between gravitational mass and inertial mass, which in specific electromagnetic conditions, can be reduced, made negative and increased in numerical value. This means that gravitational forces can be reduced, inverted and intensified by means of electromagnetic fields. Such control of the gravitational intera

Renyue Cen

There was a bright, transient companion spot to SN1987A with a projected distance of about 17 light-days, observed by optical speckle interferometry one to two months after explosion. It is shown here that the bright spot may be due to a receding ultra-relativistic jet traveling at 53 degress to the observer-to-SN1987A vector, through a circumstellar medium

Jose D. Edelstein, Marta Gomez-Reino, Javier Mas

We compute instanton corrections to the low energy effective prepotential of N=2 supersymmetric theories in a variety of cases, including all classical gauge groups and even number of fundamental matter hypermultiplets. To this end, we take profit of a set of first- and second-order equations for the logarithmic derivatives of the prepotential with respect t

Lajos Diosi

Multiparticle boson states, proposed recently for &#39;independently&#39; emitted pions in heavy ion collisions, are reconsidered in standard second quantized formalism and shown to emerge from a simplistic chaotic current dynamics. Compact equations relate the density operator, the generating functional of multiparticle counts, and the correlator of the ext

M. S. Tomassone, J. B. Sokoloff

The effects of a step defect and a random array of point defects (such as vacancies or substitutional impurities) on the force of friction acting on a xenon monolayer film as it slides on a silver (111) substrate are studied by molecular dynamic simulations and compared with the results of lowest order perturbation theory in the substrate corrugation potenti

Elisabete M. de Gouveia Dal Pino

We report the results of three-dimensional smoothed particle hydrodynamics simulations of interactions of overdense, radiatively cooling and adiabatic jets with dense, compact clouds in frontal and off-axis collisions. Calculated for a set of parameters which are particularly appropriate to protostellar jets, our results indicate that the interaction produce

J. E. Amaro, A. M. Lallena, J. A. Caballero

An analysis of the effects of meson exchange and isobar currents in exclusive (e,e&#39;p) processes from O-16 under quasi-free kinematics is presented. A model that has probed its feasibility for inclusive quasi-elastic (e,e&#39;) processes is considered. Sensitivity to final state interactions between the outgoing proton and the residual nucleus is discusse

G. B. Cleaver, A. E. Faraggi, D. V. Nanopoulos

Three family SU(3)_C x SU(2)_L x U(1)_Y string models in several constructions generically possess two features: (i) an extra local anomalous U(1)_A and (ii) numerous (often fractionally charged) exotic particles beyond those in the minimal supersymmetric model (MSSM). Recently, we demonstrated that the observable sector effective field theory of such a free

O. Barabash, Yu. Shtanov

We study the weak-field limit of the static spherically symmetric solution of the locally conformally invariant theory advocated in the recent past by Mannheim and Kazanas as an alternative to Einstein&#39;s General Relativity. In contrast with the previous works, we consider the physically relevant case where the scalar field that breaks conformal symmetry

L. M. Haffner, R. J. Reynolds, S. L. Tufte

A large portion of the Galaxy (l = 123 deg to 164 deg, b = -6 deg to -35 deg), which samples regions of the Local (Orion) spiral arm and the more distant Perseus arm, has been mapped with the Wisconsin H-Alpha Mapper (WHAM) in the H-Alpha, [S II] 6716, and [N II] 6583 lines. Several trends noticed in emission-line investigations of diffuse gas in other galax

Jean-Francois Burnol

We establish Connes&#39;s local trace formula (related to the explicit formulae of number theory) for the quaternions. This is done as an application of a study of the central operator H = log(|x|) + log(|y|) in the context of invariant harmonic analysis. The multiplicative analysis of the additive Fourier transform gives a spectral interpretation to general

Donam Youm

We study the generalized conformal quantum mechanics of the probe D0-brane in the near horizon background of the bound state of source D0-branes. We elaborate on the relationship of such model to the M theory in the light cone frame.

M. Murgia, C. Fanti, R. Fanti, L. Gregorini

The high-frequency integrated spectra of Compact Steep Spectrum (CSS) sources show breaks with a moderate spectral steepening well fitted by continuous injection synchrotron spectra. In lobe-dominated CSS sources the radiative ages deduced by the synchrotron theory are in the range of up to 0.1 Myears, if equipartition magnetic fields are assumed. These radi

K. -I. Izawa, Kiichi Kurosawa, Yasunori Nomura, T. Yanagida

We discuss the anomalous U(1) gauge symmetry as a mechanism of generating the grand-unification scale. We conclude that unification to a simple group cannot be realized unless some parameters are ``tuned&#39;&#39;, and that models with product gauge groups are preferred. We consider the ``R-invariant natural unification&#39;&#39; model with gauge groups SU(5

A. Echeverria-Enriquez, M. C. Munoz-Lecanda, N. Roman-Roy

We study the geometrical background of the Hamiltonian formalism of first-order Classical Field Theories. In particular, different proposals of multimomentum bundles existing in the usual literature (including their canonical structures) are analyzed and compared. The corresponding Legendre maps are introduced. As a consequence, the definition of regular and

Eric Bergshoeff, Ergin Sezgin, Antoine Van Proeyen

We construct the supercurrent multiplet that contains the energy-momentum tensor of the (2,0) tensor multiplet. By coupling this multiplet of currents to the fields of conformal supergravity, we first construct the linearized superconformal transformations rules of the (2,0) Weyl multiplet. Next, we construct the full non-linear transformation rules by gaugi

Kouichi Okunishi, Yasuhiro Hieida, Yasuhiro Akutsu

We study the zero-temperature magnetization process (M-H curve) of one-dimensional quantum antiferromagnets using a variant of the density-matrix renormalization group method. For both the S=1/2 zig-zag spin ladder and the S=1 bilinear-biquadratic chain, we find clear cusp-type singularities in the middle-field region of the M-H curve. These singularities ar

C. Grimaldi, L. Pietronero

The nonadiabatic regime of the electron-phonon interaction leads to behaviors of some physical measurable quantities qualitatively different from those expected from the Migdal-Eliashberg theory. Here we identify in the Pauli paramagnetic susceptibility $χ$ one of such quantities and show that the nonadiabatic corrections reduce $χ$ with respect to its adiab

N. Mandolesi, M. Bersanelli, C. Burigana, F. Villa

The Low Frequency Instrument (LFI) of the "Planck Surveyor" ESA mission will perform high-resolution imaging of the Cosmic Microwave Background anisotropies at four frequencies in the 30-100 GHz range. We review the LFI main scientific objectives, the current status of the instrument design and the on-going effort to develop software simulations of the LFI o

F. Meier, W. Zwerger

Based on a tunneling Hamiltonian description, we calculate the Josephson, normal and interference currents between two Bose-Einstein condensates described by the Bogoliubov theory. The dominant Josephson term is of first order in the tunneling with a critical current density proportional to the ground state pressure. In contrast to superconductors, the norma

Mahendra K. Verma

We numerically calculate the energy spectrum, intermittency exponents, and probability density $P(u&#39;)$ of the one-dimensional Burgers and KPZ equations with correlated noise. We have used pseudo-spectral method for our analysis. When $σ$ of the noise variance of the Burgers equation (variance $\propto k^{-2 σ}$) exceeds 3/2, large shocks appear in the ve

Kiyoshi Hayasaka, Ryuichi Nakayama

It is shown that the effective theory of D-particles has conformal symmetry with field-dependent parameters. This is a consequence of the supersymmetry. The string coupling constant is not transformed in contrast with the recent proposal of generalized conformal symmtery by Jevicki et al. This conformal symmetry can also be generalized to other Dp-brane syst

A. I. Sanda

In our subgroup, we focused on penguin physics from various different angles. Our discussions included: (1) A method to extract one of the angles of the unitarity triangle $ϕ_2$; (2) Methods to extract $ϕ_3$ from $B\to Kπ$ decays; (3) Effects of non-minimal SUSY on B and K decays; (4) Understnding large branching ratios for $B\to η&#39;+K(K^*)$ decays; (5) N

A. Heger, N. Langer, S. E. Woosley

The evolution of rotating stars with zero-age main sequence (ZAMS) masses in the range 8 to 25 M_sun is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star&#39;s equatorial rotational velocity on the ZAMS ranges from zero to ~ 70 % of break-up. Redistribution of angular momentum and chemical species are

Ronald J. Adler, David I. Santiago

Heisenberg showed in the early days of quantum theory that the uncertainty principle follows as a direct consequence of the quantization of electromagnetic radiation in the form of photons. As we show here the gravitational interaction of the photon and the particle being observed modifies the uncertainty principle with an additional term. From the modified

Apoloniusz Tyszka

TO APPEAR IN AEQUATIONES MATHEMATICAE - WITHOUT THEOREM 2. THEOREM 2 IS CORRECTLY PROVED IN PREVIOUS VERSIONS 1 AND 2. AUTHOR&#39;S VERSION 3 (WITH A NEW FIGURE 6A) IS UNNECESSARY. Let F \subseteq R denote the field of numbers which are constructible by means of ruler and compass. We prove that: (1) if x,y \in R^n (n>1) and |x-y| is an algebraic number then

David F. Crawford

A hypothesis of curvature pressure is used to derive a static and stable cosmology with a tired-light redshift. The idea is that the high energy particles in the inter-galactic medium do not travel along geodesics because of the strong electrostatic forces. The result is a reaction back on the medium that is seen as an additional pressure. Combined with the

P. Fendley, H. Saleur

Functional relations play a key role in the study of integrable models. We argue in this paper that for massless field theories at zero temperature, these relations can in fact be interpreted as monodromy relations. Combined with a recently discovered duality, this gives a way to bypass the Bethe ansatz, and compute directly physical quantities as solutions

R. Myrzakulov

The (2+1)-dimensional integrable M-XX equation is considered.

Robert Gingrich, Colin P. Williams, Nicolas Cerf

We generalize Grover&#39;s unstructured quantum search algorithm to enable it to use an arbitrary starting superposition and an arbitrary unitary matrix simultaneously. We derive an exact formula for the probability of the generalized Grover&#39;s algorithm succeeding after n iterations. We show that the fully generalized formula reduces to the special cases

Jaroslav Rehacek, Zdenek Hradil, Michael Zawisky, Saverio Pascazio

Various phase concepts may be treated as special cases of the maximum likelihood estimation. For example the discrete Fourier estimation that actually coincides with the operational phase of Noh, Fouge`res and Mandel is obtained for continuous Gaussian signals with phase modulated mean.Since signals in quantum theory are discrete, a prediction different from

A. C. Doherty, A. S. Parkins, S. M. Tan, D. F. Walls

We consider effects of motion in cavity quantum electrodynamics experiments where single cold atoms can now be observed inside the cavity for many Rabi cycles. We discuss the timescales involved in the problem and the need for good control of the atomic motion, particularly the heating due to exchange of excitation between the atom and the cavity, in order t

Y. Japha, G. Kurizki

We study the use of the Faraday effect as a quantum clock for measuring traversal times of evanescent photons through magneto-refractive structures. The Faraday effect acts both as a phase-shifter and as a filter for circular polarizations. Only measurements based on the Faraday phase-shift properties are relevant to the traversal time measurements. The Fara

Xi-Wen Hou, Shi-Hai Dong, Zhong-Qi Ma

A U(2) algebraic model is presented to describe stretching vibrations of XY$_n$ (n=2, 3, and 4) systems, where anharmonic interactions between the bond modes are considered. This model in a limit corresponds to an anharmonically coupled local mode model. As an example, the model for a molecule XY$_4$ is applied to recently observed spectra of methane in both

Xi-Wen Hou, Shi-Hai Dong, Zhong-Qi Ma

A Fermi resonance-algebraic model is proposed for molecular vibrations, where a U(2) algebra is used for describing the vibrations of each bond, and Fermi resonances between stretching and bending modes are taken into account. The model for a bent molecule XY_2 and a molecule XY_3 is successfully applied to fit the recently observed vibrational spectrum of t

D. T. Son

We show that the decay of a passive scalar $θ$ advected by a random incompressible flow with zero correlation time in Batchelor limit can be mapped exactly to a certain quantum-mechanical system with a finite number of degrees of freedom. The Schroedinger equation is derived and its solution is analyzed for the case when at the beginning the scalar has Gauss

C. A. da Rocha, G. A. Miller, U. van Kolck

Power-counting arguments are used to organize the interactions contributing to the N N -> d pi, p n pi reactions near threshold. We estimate the contributions from the three formally leading mechanisms: the Weinberg-Tomozawa (WT) term, the impulse term, and the $Δ$-excitation mechanism. Sub-leading but potentially large mechanisms, including $S$-wave pion-re

A. S. Rinat, M. F. Taragin

We study implications of a model, which links nuclear and nucleon structure functions. Computed Callen-Gross functions $κ^A(x,Q^2)= 2xF_1^A(x,Q^2)/F_2^A(x,Q^2)$ appear for finite $Q^2$ to be close to their asymptotic value 1. Using those $κ$, we compure $R$ ratios for $Q^2\ge 5 GeV^2$. We review approximate methods in use for the extraction of $R$ from inclu