June 2001 arXiv papers — page 4
Showing 301–400 of 2,845 papers
C. Ungarelli, A. Vecchio
A plethora of gravitational wave stochastic backgrounds populate the sensitivity window of the Laser Interferometer Space Antenna. We show that LISA can detect the anisotropy of the background corresponding to the multipole moments of order l=2 and 4. The signal-to-noise ratio generated by galactic white dwarf binary systems could be as high as 60 for 3 yrs
D. Montes, J. Lopez-Santiago, M. C. Galvez, M. J. Fernandez-Figueroa
This is the first paper of a series aimed at studying the properties of late-type stars members of young stellar kinematic groups. We concentrate our study on classical young moving groups as: Local Association (Pleiades moving group, 20 - 150 Myr), IC 2391 supercluster (35 Myr), Ursa Major group (Sirius supercluster, 300 Myr), and Hyades supercluster (600 M
R. Ruffini, C. L. Bianco, P. Chardonnet, F. Fraschetti
The relative-space-time-transformation (RSTT) paradigm and the interpretation of the burst-structure (IBS) paradigm are applied to probe the origin of the time variability of GRBs. Again GRB 991216 is used as a prototypical case, thanks to the precise data from the CGRO, RXTE and Chandra satellites. It is found that with the exception of the relatively incon
R. Ruffini, C. L. Bianco, P. Chardonnet, F. Fraschetti
The data from the Chandra satellite on the iron emission lines in the afterglow of GRB 991216 are used to give further support for the EMBH theory, which links the origin of the energy of GRBs to the extractable energy of electromagnetic black holes (EMBHs), leading to an interpretation of the GRB-supernova correlation. Following the relative space-time tran
R. Ignace
The problem of detecting Jovian-sized planets orbiting White Dwarf stars is considered. Significant IR excesses result from warm Jupiters orbiting a White Dwarf of $T_{\rm eff}=10000$ K at a distance of $\sim 10^3$ White Dwarf radii (corresponding to $\sim 10^2$ Jupiter radii or a few tenths of an AU) with an orbital period of $\sim 100$ days. Such a planet
R. Ruffini, C. L. Bianco, P. Chardonnet, F. Fraschetti
The GRB 991216 and its relevant data acquired from the BATSE experiment and RXTE and Chandra satellites are used as a prototypical case to test the theory linking the origin of gamma ray bursts (GRBs) to the process of vacuum polarization occurring during the formation phase of a black hole endowed with electromagnetic structure (EMBH). The relative space-ti
Rüdiger Schopper, Guido Thorsten Birk, Harald Lesch
Within an electric circuit description of extragalactic jets temporal variations of the electric currents are associated with finite collisionless conductivities and consequently magnetic-field aligned electric fields $E_\parallel$. The maximum field strengths depend on the efficiency of the jet MHD generator $E_\perp$ and the local conversion to the $E_\par
Long-Slit Observations of Extended C II 1335 Emission Around V854 Centauri and RY Sagittarii
astro-phGeoffrey C. Clayton, T. R. Ayres
We have obtained long-slit far-ultraviolet (1150--1730 A) spectra of the R Coronae Borealis (RCB) stars V854 Cen and RY Sgr, near maximum light and pulsational phase zero, with the Space Telescope Imaging Spectrograph (STIS) on Hubble Space Telescope (HST). The far-UV spectrum of each star shows a photospheric continuum rising steeply toward longer wavelengt
A search for gamma-ray emission from the Galactic plane in the longitude range between 37 deg and 43 deg
astro-phHEGRA-Collaboration, F. Aharonian
Using the HEGRA system of imaging atmospheric Cherenkov telescopes, a region of the Galactic plane (-10 deg < b < 5 deg, 38 deg < l < 43 deg) was surveyed for TeV gamma-ray emission, both from point sources and of diffuse nature. The region covered includes 15 known pulsars, 6 known supernova remnants (SNR) and one unidentified EGRET source. No evidence for
Jet launching theory and the vertical structure of a magnetically-dominated thin accretion disc
astro-phG. Rudiger, D. A. Shalybkov
The presence of an imposed external magnetic field may drastically influence the structure of thin accretion discs. The magnetic field energy is here assumed to be in balance with the thermal energy of the accretion flow. The vertical magnetic field, its toroidal component B^tor at the disc surface (due to different rotation rates between disc and its magnet
The contribution of galaxies to the UV ionising background and the evolution of the Lyman forest
astro-phSimone Bianchi, Stefano Cristiani, Tae-Sun Kim
We have modelled the evolution of the number of Ly_alpha absorbers with redshift, resulting from the evolution of the ionising background and the Hubble expansion. The contribution of quasars (QSOs) and galaxies to the HI-ionising UV background has been estimated. The QSOs emissivity is derived from recent fits of their luminosity function. The galaxy emissi
G. Rudiger, A. Drecker
The velocity fluctuations in a spherical shell arising from sinusoidal perturbations of a Keplerian shear flow with a free amplitude parameter εare studied numerically by means of fully 3D nonlinear simulations. The investigations are performed at high Reynolds numbers, i.e. 3000 < Re < 5000. We find Taylor-Proudman columns of large eddies parallel to the ro
Kenji Bekki, Masashi Chiba
We perform numerical simulations for the formation of the Galactic stellar halo, based on the currently favored cold dark matter (CDM) theory of galaxy formation. Our numerical models, taking into account both dynamical and chemical evolution processes in a consistent manner, are aimed at explaining observed structure and kinematics of the stellar halo in th
The Parkes Multibeam Pulsar Survey: I. Observing and Data Analysis Systems, Discovery and Timing of 100 Pulsars
astro-phR. N. Manchester, A. G. Lyne, F. Camilo, J. F. Bell
The Parkes multibeam pulsar survey is a sensitive survey of a strip along the Galactic plane with |b|<5 deg and l=260 deg to l=50 deg. It uses a 13-beam receiver on the 64-m Parkes radio telescope, receiving two polarisations per beam over a 288 MHz bandwidth centred on 1374 MHz. Receiver and data acquisition systems are described in some detail. For pulsar
Akio K. Inoue
We examine Lyman continuum extinction (LCE) in H II regions by comparing infrared fluxes of 49 H II regions in the Galaxy, M31, M33, and the LMC with estimated production rates of Lyman continuum photons. A typical fraction of Lyman continuum photons that contribute to hydrogen ionization in the H II regions of three spiral galaxies is $\la$ 50 %. The fracti
A Composite Seyfert 2 X-ray Spectrum: Implications for the Origin of the Cosmic X-ray Background
astro-phEdward C. Moran, Laura E. Kay, Marc Davis, Alexei V. Filippenko
We present a composite 1-10 keV Seyfert 2 X-ray spectrum, derived from ASCA observations of a distance-limited sample of nearby galaxies. All 29 observed objects were detected. Above ~3 keV, the composite spectrum is inverted, confirming that Seyfert 2 galaxies as a class have the spectral properties necessary to explain the flat shape of the cosmic X-ray ba
First Application of the Fe XVII I(17.10 A)/I(17.05 A) Line Ratio to Constrain the Plasma Density of a Cosmic X-ray Source
astro-phChristopher W. Mauche, Duane A. Liedahl, Kevin B. Fournier
We show that the Fe XVII I(17.10 A)/I(17.05 A) line ratio observed in the Chandra HETG spectrum of the intermediate polar EX Hydrae is significantly smaller than that observed in the Sun or other late-type stars. Using the Livermore X-ray Spectral Synthesizer, which calculates spectral models of highly charged ions based on HULLAC atomic data, we find that t
R. Launhardt, B. Stecklum, A. I. Sargent
We present new sub-arcsecond-resolution near-infrared polarimetric imaging and millimetre interferometry data on the circumstellar disk system in the Bok globule CB26. The data imply the presence of a M > 0.01 M_sun edge-on disk of >400 AU in diameter, being in Keplerian rotation around a young ~0.35 M_sun star. The mm dust emission from the inner 200 AU is
Stephen S. Murray, Scott M. Ransom, Michael Juda, Una Hwang
A 50 ksec observation of the Supernova Remnant Cas A was taken using the Chandra X-Ray Observatory High Resolution Camera (HRC) to search for periodic signals from the compact source located near the center. Using the HRC-S in imaging mode, problems with correctly assigning times to events were overcome, allowing the period search to be extended to higher fr
Benjamin D. Wandelt, Frode K. Hansen
We describe a class of observational strategies for probing the anisotropies in the cosmic microwave background (CMB) where the instrument scans on rings which can be combined into an n-torus, the {\em ring torus}. This class has the remarkable property that it allows exact maximum likelihood power spectrum estimation in of order $N^2$ operations (if the siz
Andreas Karch, Emanuel Katz, Lisa Randall
We clarify the role of gauge invariance for the theory of an AdS4 brane embedded in AdS5. The presence of a nonvanishing mass parameter even for the lightest KK mode of the graviton indicates that all of the spin-2 modes propagate five polarization states. Despite this fact, it was shown earlier that the classical theory has a smooth limit as the mass parame
K. M. Mertes, Yoko Suzuki, M. P. Sarachik, Y. Paltiel
In magnetic fields applied parallel to the anisotropy axis, the relaxation of the magnetization of Mn$_{12}$ measured for different sweep rates is shown to collapse onto a single scaled curve. The form of the scaling implies that the dominant symmetry-breaking process that gives rise to tunneling is a locally varying second-order anisotropy, forbidden by tet
Motohiko Tanaka, A. Yu. Grosberg
We have performed molecular dynamics simulations to study the effect of an external electric field on a macroion in the solution of multivalent Z:1 salt. To obtain plausible hydrodynamics of the medium, we explicitly make the simulation of many neutral particles along with ions. In a weak electric field, the macroion drifts together with the strongly adsorbe
SO(3) Monopoles, Level-One Seiberg-Witten Moduli Spaces, and Witten's Conjecture in Low Degrees
math.DGPaul M. N. Feehan, Thomas G. Leness
We prove Witten's formula relating the Donaldson and Seiberg-Witten series modulo powers of degree $c+2$, with $c=-{1/4}(7χ+11σ)$, for four-manifolds obeying some mild conditions, where $χ$ and $σ$ are their Euler characteristic and signature. We use the moduli space of SO(3) monopoles as a cobordism between a link of the Donaldson moduli space of anti-s
A. Cavaliere, V. D'Elia
We propose a sequence (the Blazar main sequence, BMS) that links the two main components of the Blazar class, namely, the Flat Spectrum Radio Quasars and the BL Lacertae objects, and yields all their distinctive features in a correlated way. In this view, both type of sources are centered on a supermassive Kerr hole close to maximal spin that produces a rela
Mitchell G. Moore, Anne Juel, John M. Burgess, W. D. McCormick
Our experiments on viscous (Saffman-Taylor) fingering in Hele-Shaw channels reveal finger width fluctuations that were not observed in previous experiments, which had lower aspect ratios and higher capillary numbers Ca. These fluctuations intermittently narrow the finger from its expected width. The magnitude of these fluctuations is described by a power law
Nick E. Mavromatos, Richard J. Szabo
We construct the consistent supersymmetric extensions of the operators describing the recoil of a D-brane and show that they realize an N=1 logarithmic superconformal algebra. The corresponding supersymmetric vertex operator is related to the action of a twisted superparticle with twist field determined by the angular momentum of the recoiling D-brane and wi
R. G. Carlberg, H. K. C. Yee, S. L. Morris, H. Lin
(abridged) The systematic variation of galaxy colors and types with clustering environment could either be the result of local conditions at formation or subsequent environmental effects as larger scale structures draw together galaxies whose stellar mass is largely in place. At z~0.4 the co-moving galaxy correlation length, r_0, measured in the CNOC2 sample
Daniel Collins, Sandu Popescu
Results obtained in two recent papers, \cite{Kaszlikowski} and \cite{Durt}, seem to indicate that the nonlocal character of the correlations between the outcomes of measurements performed on entangled systems separated in space is not robust in the presence of noise. This is surprising, since entanglement itself is robust. Here we revisit this problem and ar
K. H. Lockitch, N. Andersson, A. L. Watts
We present results for r-modes of relativistic nonbarotropic stars. We show that the main differential equation, which is formally singular at lowest order in the slow-rotation expansion, can be regularized if one considers the initial value problem rather than the normal mode problem. However, a more physically motivated way to regularize the problem is to
A gobal fit to the anomalous magnetic moment, b->s gamma and Higgs limits in the constrained MSSM
hep-phW. de Boer, M. Huber, C. Sander, D. I. Kazakov
New data on the anomalous magnetic moment a_mu of the muon together with the b->s gamma decay rate are considered within the supergravity inspired constrained minimal supersymmetric model. We perform a global statistical chi^2 analysis of these data and show that the allowed region of parameter space is bounded from below by the Higgs limit, which depends on
A. Mourachkine
The main purpose of the paper is to present an overview of the current situation in the development of understanding of the mechanism of high-Tc superconductivity which arises due to moderately strong, nonlinear electron-phonon interactions and due to magnetic (spin) fluctuations.
Antonio Scala, Francesco Sciortino
Starting for the Stillinger and Weber expression for the free energy of supercooled liquids, we extend the free energy to the case in which two time scales separate and the system is in quasi-equilibrium. The concept of an effective temperature, different from the kinetic temperature, is naturally introduced. An example of hypotetical quasi-equilibrium phase
J. Vidal, B. Doucot
We study a system in which the quantum dynamics of electrons depend on the particle density in their neighborhood. For any on-site repulsive interaction, we show that the exact two-body and three-body ground states are bound states. We also discuss the finite density case in a mean-field framework and we show that the system can undergo an unusual transition
Stefano Arnone, Yuri A. Kubyshin, Tim R. Morris, John F. Tighe
We construct a gauge invariant regularisation scheme for pure SU(N) Yang-Mills theory in fixed dimension four or less (for N = infinity in all dimensions), with a physical cutoff scale Lambda, by using covariant higher derivatives and spontaneously broken SU(N|N) supergauge invariance. Providing their powers are within certain ranges, the covariant higher de
Weakly nonlocal irreversible thermodynamics - the Guyer-Krumhansl and the Cahn-Hilliard equations
cond-mat.mtrl-sciPeter Van
Examples of irreversible thermodynamic theory of nonlocal phenomena are given, based on generalized entropy current. Thermodynamic currents and forces are identified to derive the Guyer-Krumhansl and Cahn-Hilliard equations. In the latter case Gurtin's rate dependent additional term is received through the thermodynamic approach.
Nuclearity, Local Quasiequivalence and Split Property for Dirac Quantum Fields in Curved Spacetime
math-phClaudio D'Antoni, Stefan Hollands
We show that a free Dirac quantum field on a globally hyperbolic spacetime has the following structural properties: (a) any two quasifree Hadamard states on the algebra of free Dirac fields are locally quasiequivalent; (b) the split-property holds in the representation of any quasifree Hadamard state; (c) if the underlying spacetime is static, then the nucle
Luis A. Anchordoqui, Haim Goldberg, Stephen Reucroft, Gustavo E. Romero
We examine the correlation between compact radio quasars (redshifts in the range $z = 0.3 - 2.2$) and the arrival direction of ultrahigh energy cosmic rays forming clusters. Our Monte Carlo simulation reveals a statistically significant correlation on the AGASA sample: the chance probability of this effect being less than 1%. The implications of this result
Ram Brustein, David Eichler, Stefano Foffa
Quantum gravity "foam", among its various generic Lorentz non-invariant effects, would cause neutrino mixing. It is shown here that, if the foam is manifested as a nonrenormalizable effect at scale M, the oscillation length generically decreases with energy $E$ as (E/M)^(-2). Neutrino observatories and long-baseline experiments should have therefore
Comparison between two methods of post-Newtonian expansion for the motion in a weak Schwarzschild field
gr-qcMayeul Arminjon
The asymptotic method of post-Newtonian (PN) expansion for weak gravitational fields, recently developed, is compared with the standard method of PN expansion, in the particular case of a massive test particle moving along a geodesic line of a weak Schwarzschild field. First, the expression of the active mass in Schwarzschild's solution is given for a ba
K. -I. Goh, B. Kahng, D. Kim
We study a problem of data packet transport in scale-free networks whose degree distribution follows a power-law with the exponent $γ$. We define load at each vertex as the accumulated total number of data packets passing through that vertex when every pair of vertices send and receive a data packet along the shortest path connecting the pair. It is found th
Paul Benioff
The representation of numbers by product states in quantum mechanics can be extended to the representation of words and word sequences in languages by product states. This can be used to study quantum systems that generate text that has meaning. A simple example of such a system, based on an example described by Smullyan, is studied here. Based on a path int
Matthew Colless, G. B. Dalton, S. J. Maddox, W. J. Sutherland
The 2dF Galaxy Redshift Survey (2dFGRS) is designed to measure redshifts for approximately 250000 galaxies. This paper describes the survey design, the spectroscopic observations, the redshift measurements and the survey database. The 2dFGRS uses the 2dF multi-fibre spectrograph on the Anglo-Australian Telescope, which is capable of observing 400 objects sim
J. R. Cudell, G. Soyez
We show that the latest HERA measurements of F2 are compatible with the existence of a triple pole at J=1. Such a structure also accounts for soft forward hadronic amplitudes, so that the introduction of a new singularity is not necessary to describe DIS data.
Quantum-dot lithium in zero magnetic field: Electronic properties, thermodynamics, and a liquid-solid transition in the ground state
cond-mat.str-elS. A. Mikhailov
Energy spectra, electron densities, pair correlation functions and heat capacity of a quantum-dot lithium in zero external magnetic field (a system of three interacting two-dimensional electrons in a parabolic confinement potential) are studied using the exact diagonalization approach. A particular attention is given to a Fermi-liquid -- Wigner-solid transit
Nathan F. Lepora
Using the embedded defect method, we classify the possible embeddings of a 't Hooft-Polyakov monopole in a general gauge theory. We then discuss some similarities with embedded vortices and relate our results to fundamental monopoles.
Restrictions on the coherence of the ultrafast optical emission from an electron-hole pairs condensate
cond-mat.mes-hallA. Olaya-Castro, F. J. Rodriguez, L. Quiroga, C. Tejedor
We report on the transfer of coherence from a quantum-well electron-hole condensate to the light it emits. As a function of density, the coherence of the electron-hole pair system evolves from being full for the low density Bose-Einstein condensate to a chaotic behavior for a high density BCS-like state. This degree of coherence is transfered to the light em
M. Plionis, S. Basilakos
We study the size and shape of low density regions in the local universe which we identify in the smoothed density field of the PSCz flux limited IRAS galaxy catalogue. After quantifying the systematic biases that enter in the detection of voids using our data set and method, we identify, using a smoothing length of 5 $h^{-1}$ Mpc, 14 voids within 80 $h^{-1}
Masako Asano
We study Myers world-volume effective action of coincident D-branes. We investigate a system of N_0 D0-branes in the geometry of Dp-branes with p=2 or p=4. The choice of coordinates can make the action simplified and tractable. For p=4, we show that a certain point-like D0-brane configuration solving equations of motion of the action can expand to form a fuz
Mokhtar Hassaine
Using a Kaluza-Klein framework, we consider a relativistic fluid whose projection yields the supersymmetric non-relativistic Chaplygin gas introduced by Bergner-Jackiw-Polychronakos and by Hoppe. The conserved (super)charges of the Chaplygin gas are obtained as the projection of those arising in the extended model.
Hamish G. Rose
Apparent magnitudes are important for high precision cosmology. It is generally accepted that weak gravitational lensing does not affect the relationship between apparent magnitude and redshift. By considering metric perturbations it is shown that objects observed in an inhomogeneous universe have, on average, higher apparent magnitudes than those observed a
J. H. Kühn, S. Moch, A. A. Penin, V. A. Smirnov
We sum up the next-to-next-to-leading logarithmic virtual electroweak corrections to the high energy asymptotics of the neutral current four-fermion processes for light fermions to all orders in the coupling constants using the evolution equation approach. From this all order result we derive finite order expressions through next-to-next-to leading order for
M. Picco, F. Ritort, M. Sales
A detailed investigation of lowest excitations in two-dimensional Gaussian spin glasses is presented. We show the existence of a new zero-temperature exponent lambda describing the relative number of finite-volume excitations with respect to large-scale ones. This exponent yields the standard thermal exponent of droplet theory theta through the relation, the
Symmetry of high-piezoelectric Pb-based complex perovskites at the morphotropic phase boundary II. Theoretical treatment
cond-mat.mtrl-sciYasusada Yamada, Yoshiaki Uesu, Masaaki Matsuda, Kouji Fujishiro
The structural characteristics of the perovskite- based ferroelectric Pb(Zn1/3Nb2/3)O3-9%PbTiO3 at the morphotropic phase boundary (MPB) region (x≃0.09) have been analyzed. The analysis is based on the symmetry adapted free energy functions under the assumption that the total polarization and the unit cell volume are conserved during the transformation
Symmetry of high-piezoelectric Pb-based complex perovskites at the morphotropic phase boundary I. Neutron diffraction study on Pb(Zn1/3Nb2/3)O3 -9%PbTiO3
cond-mat.mtrl-sciYoshiaki Uesu, Masaaki Matsuda, Yasusada Yamada, Kouji Fujishiro
The symmetry was examined using neutron diffraction method on Pb(Zn1/3Nb2/3)O3 -9%PbTiO3 (PZN/9PT) which has a composition at the morphotropic phase boundary (MPB) between Pb(Zn1/3Nb2/3)O3 and PbTiO3. The results were compared with those of other specimens with same composition but with different prehistory. The equilibrium state of all examined specimens is
S. J. Brodsky
Exclusive hadron production processes in photon-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes and skewed parton distributions. The determination of the shape and normalization of the distribution amplitudes has become particularly important in view of their importance in th
J. Maurice Rojas, Yinyu Ye
Let f be a degree D univariate polynomial with real coefficients and exactly m monomial terms. We show that in the special case m=3 we can approximate within eps all the roots of f in the interval [0,R] using just O(log(D)log(Dlog(R/eps))) arithmetic operations. In particular, we can count the number of roots in any bounded interval using just O(log^2 D) ari
R. R. Urbano, C. Rettori, G. E. Barberis, M. Torelli
The local environment of Gd3+ (4f7 S=7/2) ions in single crystals of Ca1-xGdxB6 (0.0001 < x < 0.01) is studied by means of Electron Spin Resonance (ESR). The spectra for low concentration samples (x < 0.001) show a split spectrum due to cubic crystal field effects(CFE). The lineshape of each fine structure line is lorentzian, indicating an insulating environ
E. Bagan, M. Baig, R. Munoz-Tapia
The communication of directions using quantum states is a useful laboratory test for some basic facts of quantum information. For a system of spin-1/2 particles there are different quantum states that can encode directions. This information can later be decoded by means of a generalized measurement. In this talk we present the optimal strategies under differ
Brian Murphy
An algorithm for structured database searching is presented and used to solve the set partition problem. O(n) oracle calls are required in order to obtain a solution, but the probability that this solution is optimal decreases exponentially with problem size. Each oracle call is followed by a measurement, implying that it is necessary to maintain quantum coh
Timothy F. Havel, Chris J. L. Doran
This paper develops a geometric model for coupled two-state quantum systems (qubits), which is formulated using geometric (aka Clifford) algebra. It begins by showing how Euclidean spinors can be interpreted as entities in the geometric algebra of a Euclidean vector space. This algebra is then lifted to Minkowski space-time and its associated geometric algeb
Claus O. Wilke
We introduce a model of molecular evolution in which the fitness of an individual depends both on its own and on the parent's genotype. The model can be solved by means of a nonlinear mapping onto the standard quasispecies model. The dependency on the parental genotypes cancels from the mean fitness, but not from the individual sequence concentrations. F
F. Garcias, Ll. Serra, M. Casas, M. Barranco
The multipole response of $^3$He$_N$ drops doped with very attractive impurities, such as a Xe atom or an SF$_6$ molecule, has been investigated in the framework of the Finite Range Density Functional Theory and the Random Phase Approximation. We show that volume ($L$ = 0) and surface ($L$ = 1, 2) modes become more fragmented, as compared with the results ob
K. A. Jensen, R. J. Larson, S. D. Bergeson, E. F. McCormack
We present two experiments in closed-loop feedback control. In the first experiment, students control the pointing angle of a laser to "lock" the laser onto a "target." In the second, students stabilize the pathlength difference in two arms of a Michelson interferometer. These experiments are appropriate for electronics and optics laboratory
D. Vincenzi
The problem of the dynamo effect for a Kraichnan incompressible helicity-free velocity field is considered. Exploiting a quantum formalism first introduced by Kazantsev (A.P. Kazantsev, Sov. Phys. JETP 26, 1031-1034 (1968)), we show that a critical magnetic Reynolds number exists for the presence of dynamo. The value of the Prandtl number influences the spat
Sub-nanosecond, time-resolved, broadband infrared spectroscopy using synchrotron radiation
physics.ins-detR. P. S. M. Lobo, J. D. LaVeigne, D. H. Reitze, D. B. Tanner
A facility for sub-nanosecond time-resolved (pump-probe) infrared spectroscopy has been developed at the National Synchrotron Light Source of Brookhaven National Laboratory. A mode-locked Ti:sapphire laser produces 2 ps duration, tunable near-IR pump pulses synchronized to probe pulses from a synchrotron storage ring. The facility is unique on account of the
Avraham Gal
Using to a minimum extent special relativity input, and relying on the Lorentz-force expression for the force acting on a charged particle in motion under the influence of electric (E) and magnetic (B) fields, the Maxwell curl equations are shown to follow from the covariance of the two Maxwell divergence equations ${÷\cdot E} = 4πρ$ and ${÷\cdot B} = 0$.
P. J. Leo, V. Venturi, I. B. Whittingham, J. F. Babb
We report scattering lengths for the singlet Sigma g +, triplet Sigma u + and quintet Sigma g + adiabatic molecular potentials relevant to collisions of two metastable (n=2 triplet S) helium atoms as a function of the uncertainty in these potentials. These scattering lengths are used to calculate experimentally observable scattering lengths, elastic cross se
Avraham Gal
Antiproton-nucleus optical potentials fitted to $\bar p$-atom level shifts and widths are used to calculate the recently reported very low energy ($p_{L}<100$ MeV/c) $\bar p$ cross sections for annihilation on light nuclei. The apparent suppression of annihilation upon increasing the atomic charge $Z$ and mass number $A$ is resolved as due to the strong effe
M. J. Boland, M. A. Garbu tt, R. P. Rassool, M. N. Thompson
A broad excited state was observed in 6-He with energy E_x = 5 +/- 1 MeV and width Gamma = 3 +/- 1 MeV, following the reaction Li-7(gamma,p)He-6. The state is consistent with a number of broad resonances predicted by recent cluster model calculations. The well-established reaction mechanism, combined with a simple and transparent analysis procedure confers c
Grischa Haag, Stefan Keppeler
We investigate quantised maps of the torus whose classical analogues are ergodic but not mixing. Their quantum spectral statistics shows non-generic behaviour, i.e.it does not follow random matrix theory (RMT). By coupling the map to a spin 1/2, which corresponds to changing the quantisation without altering the classical limit of the dynamics on the torus,
James Isenberg, Steven L. Liebling
We present numerical evidence that singularities form in finite time during the evolution of 2+1 wave maps from spherically equivariant initial data of sufficient energy.
Hong Qian
We prove the equivalence among symmetricity, time reversibility, and zero entropy production of the stationary solutions of linear stochastic differential equations. A sufficient and necessary reversibility condition expressed in terms of the coefficients of the equations is given. The existence of a linear stationary irreversible process is established. Con
Tom Leinster
Higher-dimensional category theory is the study of n-categories, operads, braided monoidal categories, and other such exotic structures. Although it can be treated purely as an algebraic subject, it is inherently topological in nature: the higher-dimensional diagrams one draws to represent these structures can be taken quite literally as pieces of topology.
L. Alonso, A. Jeremias, J. Lipman
In section 8.3 of our paper "Duality and Flat Base Change on Formal Schemes" (http://arXiv.org/abs/alg-geom/9708006) some important results concerning localization of, and preservation of coherence by, basic duality functors, were based on the false statement that any closed formal subscheme of an open subscheme of the completion P of a relative proj
Trina Armstrong, Ron Umble
Let k be a field and n > 0. There exists a DG k-module (V,d) and various approximations d + t d_1 + t^2 d_2 + ... + t^n d_n to a differential on V[[t]], one of which is a non-trivial deformation, another is obstructed, and another is unobstructed at order n. The analogous problem in the category of k-algebras in characteristic zero remains a long-standing op
Oscar Lemmers, Jan Wiegerinck
Let V be a bounded, connected linearly convex set in C^n with $C^{1+ε}$-boundary. We show that the maximal ideal (both in A(V) and $H^{\infty}(V)$) consisting of all functions vanishing at p in V is generated by the coordinate functions z_1 - p_1, ..., z_n - p_n.
Weiyue Ding, Huijun Fan, Jiayu Li
We prove that a necessary condition for the existence of the remaining problem in the harmonic Hopf construction is also sufficient. We also give some topological applications based on our result.
Alexander Sergeev
I show that the projective Schur functions may be interpreted as bispherical functions of either the triple (q(n),gl(n,n),q(n)), where q(n) is the "odd" (queer) analog of the general liner Lie algebra, or the triple (p(n),gl(n,n),p(n)), where p(n) is the periplectic Lie superalgebra which preserves the nondegenerate odd, bilinear form (either symmetr
Sergei Konyagin, Francesco Pappalardi
We prove an asymptotic formula for the number of permutation for which the associated permutation polynomial has degree smaller than $q-2$.
I. Birindelli, F. Demengel
We present several Liouville type results for the $p$-Laplacian in $\R^N$. Suppose that $h$ is a nonnegative regular function such that $$ h(x) = a|x|^γ {\rm for}\ |x|\ {\rm large},\ a>0\ {\rm and}\ γ> -p. $$ We obtain the following non -existence result: 1) Suppose that $N>p>1$, and $u\in W^{1,p}_{loc} (\R^N)\cap {\cal C} (\R^N)$ is a nonnegative weak solut
Ulrich Bunke, Martin Olbrich
We obtain sufficient conditions exlcuding the existence of non-trivial distribution sections of bundles over the boundary of symmetric spaces of negative curvature which are invariant with respect to a geometrically finite group of isometries and are supported on the limit set in a strong sense.
Dmitriy Bilik, Vladimir Kadets, Roman Shvidkoy, Gleb Sirotkin
We characterise narrow and strong Daugavet operators on $C(K,E)$-spaces; these are in a way the largest sensible classes of operators for which the norm equation $\|Id+T\| = 1+\|T\|$ is valid. For certain separable range spaces $E$ including all finite-dimensional ones and locally uniformly convex ones we show that an unconditionally pointwise convergent sum
Peter A. Hasto
This paper contains bounds for the distortion in the spherical metric, that is to say bounds for the constant of Holder continuity of mappings f : (\Rn,q) -> (\Rn, q) where q denotes the spherical metric. The mappings considered are K-quasiconformal (K >= 1) and satisfy some normalizations or restrictions. All bounds are explicit and asymptotically sharp as
Michael Joswig
For each strongly connected finite-dimensional (pure) simplicial complex we construct a finite group, the group of projectivities of the complex, which is a combinatorial but not a topological invariant. This group is studied for combinatorial manifolds and, in particular, for polytopal simplicial spheres. The results are applied to a coloring problem for si
Michael Joswig, Volker Kaibel, Friederike K"orner
A k-system of the graph G(P) of a simple polytope P is a set of induced subgraphs of G(P) that shares certain properties with the set of subgraphs induced by the k-faces of P. This new concept leads to polynomial-size certificates in terms of G(P) for both the set of vertex sets of facets as well as for abstract objective functions (AOF) in the sense of Kala
C. Bohr, B. Hanke, D. Kotschick
We give explicit examples of degree 3 cohomology classes not Poincare dual to submanifolds, and discuss the realisability of homology classes by submanifolds with Spin-C normal bundles.
Ilka Brunner, Jacques Distler, Rahul Mahajan
We study D-branes on Calabi-Yau manifolds, carrying charges which are torsion elements of the K-theory. Interesting physics ensues when we follow these branes into nongeometrical phases of the compactification. On the level of K-theory, we determine the monodromies of the group of charges as we circle singular loci in the closed string moduli space. Going be
On the large N limit, W_\infty Strings, Star products, AdS/CFT Duality, Nonlinear Sigma Models on AdS spaces and Chern-Simons p-branes
hep-thCarlos Castro
It is shown that the large $N$ limit of SU(N) YM in $curved$ $m$-dim backgrounds can be subsumed by a higher $m+n$ dimensional gravitational theory which can be identified to an $m$-dim generally invariant gauge theory of diffs $N$, where $N$ is an $n$-dim internal space (Cho, Sho, Park, Yoon). Based on these findings, a very plausible geometrical interpreta
A. Pashnev, J. J. Rosales, V. I. Tkach, M. Tsulaia
In this work we have constructed the n=4 extended local conformal time supersymmetry for the Friedmann-Robertson-Walker (FRW) cosmological models. This is based on the superfield construction of the action, which is invariant under wordline local n=4 supersymmetry with $SU(2)_{local} \otimes SU(2)_{global}$ internal symmetry. It is shown that the supersymmet
Daniel Marti, Alex Pomarol
We present an N=1 superfield formulation of supersymmetric gauge theories with a compact extra dimension. The formulation incorporates the radion superfield and allows to write supersymmetric theories on warped gravitational backgrounds. We apply it to study the breaking of supersymmetry by the F-term of the radion, and show that, for flat extra dimensions,
Tony Gherghetta, Yaron Oz
We consider the supergravity dual descriptions of non-conformal super Yang-Mills theories realized on the world-volume of Dp-branes. We use the dual description to compute stress-energy tensor and current correlators. We apply the results to the study of dilatonic brane-worlds described by non-conformal field theories coupled to gravity. We find that brane-w
F. Richard, J. R. Schneider, D. Trines, A. Wagner
The TESLA Technical Design Report Part I: Executive summary
Yuri V. Kovchegov
We present the results of an analytical calculation of the distribution of gluons in the state immediately following a heavy ion collision in the quasi-classical limit of QCD given by McLerran-Venugopalan model. We show that the typical transverse energy Et of the produced gluons is of the order of the saturation scale of the nuclei Qs, as predicted by Muell
O. Cakir, S. Sultansoy
We study the observability for a Higgs boson at upgraded Tevatron via the modes gg->h->ZZ->4l (l=e,mu). We find that the signal can be observed at an integrated luminosity of 30 fb^(-1) if the fourth SM family exists.
A. V. Belitsky, G. P. Korchemsky, G. Sterman
Hadronization corrections to the thrust and related event shape distributions in the two-jet kinematical region of e+e- annihilation are summarized by nonperturbative shape functions. The moments of shape functions are given by universal matrix elements in QCD, which describe the energy flow in QCD final states. We show how the nonperturbative structure of t
A. Accardi, D. Treleani
Hadron-nucleus collisions at LHC energies are studied by including explicitly semi-hard parton rescatterings in the collision dynamics. Under rather general conditions, we obtain explicit formulae for the semi-hard cross-section and the inclusive minijet transverse spectrum. As an effect of the rescatterings the spectrum is lowered at small $p_t$ and is enha
A. V. Nesterenko
As an elaboration of the analytic approach to Quantum Chromodynamics (QCD), a new model for the QCD analytic running coupling is proposed. A self-evident advantage of the new analytic running coupling (NARC) is that it incorporates the infrared enhancement and the ultraviolet asymptotic freedom in a single expression. It is essential that additional paramete
B. C. Allanach, A. J. Barr, M. A. Parker, P. Richardson
The detection of the flavour content of jets produced from R-parity violating neutralino decays is investigated in the case where one baryon-number violating coupling dominates. Simulations are performed of the ATLAS experiment at the LHC for all couplings, other than lambda"_tjk since neutralino decays through these couplings are very suppressed. Secondary
I. M Dremin
The perturbative quantum chromodynamics (QCD) is quite successful in the description of main features of multiparticle production processes. Ten most appealing characteristics are described in this brief review talk and compared with QCD predictions. The general perturbative QCD approach is demonstrated and its problems are discussed. It is shown that the an