January 2004 arXiv papers — page 13

J. M. Metz, R. L. Cooper, M. A. Guerrero, Y. -H. Chu

We have analyzed Chandra archival observations of the Antennae galaxies to study the distribution and physical properties of its hot interstellar gas. Eleven distinct diffuse X-ray emission regions are selected according to their underlying interstellar structures and star formation activity. The X-ray spectra of these regions are used to determine their the

Eric V. Linder

In the search for the nature of dark energy most cosmological probes measure simple functions of the expansion rate. While powerful, these all involve roughly the same dependence on the dark energy equation of state parameters, with anticorrelation between its present value w_0 and time variation w_a. Quantities that have instead positive correlation and so

Naveen A. Reddy, Charles C. Steidel

We have examined the stacked radio and X-ray emission from UV-selected galaxies spectroscopically confirmed to lie between redshifts 1.5 < z < 3.0 in the GOODS-North field to determine their average extinction and star formation rates (SFRs). The X-ray and radio data are obtained from the Chandra 2 Msec survey and the Very Large Array, respectively. There is

R. L. Cooper, M. A. Guerrero, Y. -H. Chu, C. -H. R. Chen

Superbubbles surrounding OB associations provide ideal laboratories to study the stellar energy feedback problem because the stellar energy input can be estimated from the observed stellar content of the OB associations and the interstellar thermal and kinetic energies of superbubbles are well-defined and easy to observe. We have used DEM L 192, also known a

M. Vestergaard

Mass estimates, based on scaling relationships, are presented of central black holes in luminous quasars at a range of redshifts (z < 0.5, 1.2 ~< z ~< 6.3). The data show that very massive (about 10^9 solar masses or larger) black holes appear already at z ~ 6, indicating that they form very early or very fast.

Feng Yuan, Eliot Quataert, Ramesh Narayan

Recent infrared (IR) observations of the center of our Galaxy indicate that the supermassive black hole source Sgr A* is strongly variable in the IR. The timescale for the variability, $\sim 30$ min, is comparable to that of the X-ray flares observed by {\em Chandra} and {\em XMM}, suggesting a common physical origin. In this paper, we investigate the nature

Dieter Breitschwerdt, Donald P. Cox

We give a summary of the current state of Local Bubble research, resulting from the discussions of a dedicated panel meeting. After more than 25 years of intense observational and theoretical work, we are still far from a coherent picture, although a probable one emerges at the horizon. A multi-supernova origin seems to be the best guess, with non-equilibriu

Hans-Walter Rix, Marco Barden, Steven V. W. Beckwith, Eric F. Bell

GEMS, Galaxy Evolution from Morphologies and SEDs, is a large-area (800 arcmin2) two-color (F606W and F850LP) imaging survey with the Advanced Camera for Surveys on HST. Centered on the Chandra Deep Field South, it covers an area of ~28&#39;x28&#39;, or about 120 Hubble Deep Field areas, to a depth of m_AB(F606W)=28.3 (5sigma and m_AB(F850LP)=27.1 (5sigma) f

Martin J. Rees

Fred Hoyle famously drew attention to the significance of apparent coincidences in the energy levels of the carbon and oxygen nucleus. This paper addresses the possible implications of other coincidences in cosmology.

Alexandre S. Oliveira, J. E. Steiner, M. P. Diaz

In an effort to determine the orbital period of the star DI Cru, we made photometric and spectroscopic observations of this object between 1996 and 2002. The star is highly variable on short (few hours) as well as on long (few months) time-scales. The optical spectrum is rich in strong emission lines of high ionization species. Temporal Variance Spectrum - T

W. Dehnen, M. Odenkirchen, E. K. Grebel, H-W. Rix

In order to understand the extended massive tidal tails of the globular cluster Pal5, its very low mass and velocity dispersion, and its size, which is much larger than the theoretical tidal radius, we performed more than 1000 N-body simulations. Tidal shocks at disk crossings near perigalacticon dominate the evolution of extended low-concentration clusters,

F. Govoni, M. Markevitch, A. Vikhlinin, L. VanSpeybroeck

We analyze Chandra temperature maps for a sample of clusters with high quality radio halo data, to study the origin of the radio halos. The sample includes A520, A665, A754, A773, A1914, A2163, A2218, A2319, and 1E0657-56. We present new temperature maps for all but two of them (A520 and A754). All these clusters exhibit distorted X-ray morphology and strong

C. Tapken, I. Appenzeller, D. Mehlert, S. Noll

In order to study the origin of the strong Lyman-alpha emission of high-redshift starburst galaxies we observed and modeled the emission of the z = 3.304 galaxy FDF-4691 (rest-frame EW = 103 Angstroem). The observations show that FDF-4691 is a young starburst galaxy with a (for this redshift) typical metallicity. The broad, double-peaked profile of the Lyman

Frederic Pont, Laurent Eyer

A new method is presented to compute age estimates from theoretical isochrones using temperature, luminosity and metallicity data for individual stars. Based on Bayesian probability theory, this method avoids the systematic biases affecting simpler strategies, and provides reliable estimates of the age probability distribution function for late-type dwarfs.

M. Bucher, J. Dunkley, P. G. Ferreira, K. Moodley

We investigate the constraints imposed by the current data on correlated mixtures of adiabatic and non-adiabatic primordial perturbations. We discover subtle flat directions in parameter space that tolerate large (~60%) contributions of non-adiabatic fluctuations. In particular, larger values of the baryon density and a spectral tilt are allowed. The cancell

Roberto Cid Fernandes, Rosa M. Gonzalez Delgado, Henrique Schmitt, Thaisa Storchi-Bergmann

(Abridge): We present a spectroscopic study of the stellar populations of Low Luminosity AGN (LLAGN). Our main goal is to determine whether the stars who live in the innermost (100 pc-scale) regions of these galaxies are in some way related to the emission line properties, which would imply a link between the stellar population and the ionization mechanism.

Robert C. Duncan

Bright outbursts from Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs) are believed to be caused by instabilities in ultramagnetized neutron stars, powered by a decaying magnetic field. It was originally thought that these outbursts were due to reconnection instabilities in the magnetosphere, reached via slow evolution of magnetic footpoints an

Rosa M. Gonzalez Delgado, Roberto Cid Fernandes, Enrique Perez, Lucimara P. Martins

We present a study of the stellar population in Low Luminosity AGN (LLAGN). Our goal is to search for spectroscopic signatures of young and intermediate age stars, and to investigate their relationship with the ionization mechanism in LLAGN. The method used is based on the stellar population synthesis of the optical continuum of the innermost (20-100 pc) reg

Yeshe Fenner, Jason X. Prochaska, Brad K. Gibson

We have investigated chemical evolution in the young universe by analysing the detailed chemical enrichment pattern of a metal-rich galaxy at high redshift. The recent detection of over 20 elements in the gas-phase of a damped Lyman-alpha absorber (DLA) at z = 2.626 represents an exciting new avenue for exploring early nucleosynthesis. Given a strict upper a

Shinya Wanajo, Stephane Goriely, Mathieu Samyn, Naoki Itoh

The astrophysical origin of $r$-process nuclei remains a long-standing mystery. Although some astrophysical scenarios show some promise, many uncertainties involved in both the astrophysical conditions and in the nuclear properties far from the $β$-stability have inhibited us from understanding the nature of the $r$-process. The purpose of the present paper

Andreas Kaufer, Kim A. Venn, Eline Tolstoy, Christophe Pinte

We present the abundance analyses of three isolated A-type supergiant stars in the dwarf irregular galaxy Sextans A from high-resolution spectra the UVES spectrograph at the VLT. Detailed model atmosphere analyses have been used to determine the stellar atmospheric parameters and the elemental abundances of the stars. The mean iron group abundance was determ

T. Shanks

We note that the standard LCDM cosmological model continues to face fundamental problems. First, the model continues to depend wholly on two pieces of undiscovered physics, namely dark energy and cold dark matter. Then, the implied dark energy density is so small that it is unstable to quantum correction and its size is fine-tuned to the almost impossible le

Yu. N. Uzikov

Spin structure of the reaction ${\vec p}{\vec n}\to {\vec Λ^0} {\vec Θ}$ is analysed at the threshold in a model independent way under assumption that the $Θ^+$ is an isosinglet. We found that the sign of the spin-spin correlation parameter $C_{x,x}$ being measured in a double-spin experiment, determines the P-parity of the $Θ^+$ unambiguously. Furthermore w

D. J. Croton, M. Colless, E. Gaztanaga, C. M. Baugh

We measure the redshift space reduced void probability function (VPF) for 2dFGRS volume limited galaxy samples covering the absolute magnitude range M_bJ-5logh=-18 to -22. Theoretically, the VPF connects the distribution of voids to the moments of galaxy clustering of all orders, and can be used to discriminate clustering models in the weakly non-linear regi

C. M. Baugh, D. J. Croton, E. Gaztanaga, P. Norberg

We use the two-degree field Galaxy Redshift Survey (2dFGRS) to test the hierarchical scaling hypothesis: namely, that the $p$-point galaxy correlation functions can be written in terms of the two point correlation function or variance. This scaling is expected if an initially Gaussian distribution of density fluctuations evolves under the action of gravitati

Ines Caridi, Horacio Ceva

We partially modify the rules of the Minority Game (MG) by introducing some degree of local information in the game, which is only available for some agents, called the interacting agents. Our work shows that, for small values of the new parameter of the model (the fraction of interacting agents), there is an improvement of the use of the resources with resp

Agnes Mocsy, Francesco Sannino, Kimmo Tuominen

Effective Lagrangians for Quantum Chromodynamics (QCD) especially suited for understanding deconfinement and chiral symmetry restoration at nonzero temperature and matter density are reviewed. These effective theories allow one to study generic properties of phase transitions using non-order parameter fields without loosing the information encoded in the tru

Sujay K. Ashok, Eleonora Dell&#39;Aquila, Duiliu-Emanuel Diaconescu

We construct fractional branes in Landau-Ginzburg orbifold categories and study their behavior under marginal closed string perturbations. This approach is shown to be more general than the rational boundary state construction. In particular we find new D-branes on the quintic -- such as a single D0-brane -- which are not restrictions of bundles on the ambie

B. Aoun, M. Tarifi

This report introduces researchers in AI to some of the concepts in quantum heurisitics and quantum AI.

R. Gavazzi, Y. Mellier, B. Fort, J. -C. Cuillandre

We investigate the supercluster MS0302+17 (z~0.42) using weak lensing analysis and deep wide field CFH12k BVR photometry. Using (B-V) - (V-R) evolution tracks we identify supercluster early-types members. We derive a R band weak lensing background galaxies sample. We compute the correlations functions of light and mass and show that &#34;light traces mass on

Jan B. Gutowski, Harvey S. Reall

Supersymmetric, asymptotically AdS5, black hole solutions of five dimensional gauged supergravity coupled to arbitrarily many abelian vector multiplets are presented. The general nature of supersymmetric solutions of this theory is discussed. All maximally supersymmetric solutions of this theory (with or without gauging) are obtained.

A. Kashlinsky, R. Arendt, Jonathan P. Gardner, J. Mather

Following the successful mapping of the last scattering surface by WMAP and balloon experiments, the epoch of the first stars, when Population III stars formed, is emerging as the next cosmological frontier. It is not clear what these stars&#39; properties were, when they formed or how long their era lasted before leading to the stars and galaxies we see tod

F. Pistolesi

We study the charge transfer in a small grain oscillating between two leads. Coulomb blockade restricts the charge fluctuations in such a way that only zero or one additional electrons can sit on the grain. The system thus acts as a charge shuttle. We obtain the full counting statistics of charge transfer and discuss its behavior. For large oscillation ampli

P. Muhlich, L. Alvarez-Ruso, O. Buss, U. Mosel

In the present paper we investigate pi0 pi0 and pi(+/-)pi0 photoproduction off complex nuclei at incident beam energies of 400-460 MeV. Simulations of two pion photoproduction on protons and nuclei are performed by means of a semi-classical BUU transport model including a full coupled-channel treatment of the final state interactions. Elastic scattering of t

C. J. Evans, D. J. Lennon, C. Trundle, S. R. Heap

Ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) are used to determine terminal velocities for 11 O and B-type giants and supergiants in the Small Magellanic Cloud (SMC) from the Si IV and C IV resonance lines. Using archival data from observations with the Goddard High-Resolution Spectrograph and the International Ultraviolet Explore

Jose L. Cereceda

In this paper we extend Hardy&#39;s nonlocality proof for two spin-1/2 particles [PRL 71 (1993) 1665] to the case of n spin-1/2 particles configured in the generalized GHZ state. We show that, for all n \geq 3, any entangled GHZ state violates the Bell inequality associated with the Hardy experiment. This feature is important since it has been shown [PRL 88

Jacek Niemiec, Michal Ostrowski

The process of cosmic ray first-order Fermi acceleration at relativistic shock waves is studied with the method of Monte Carlo simulations. The simulations are based on numerical integration of particle equations of motion in a turbulent magnetic field near the shock. In comparison to earlier studies, a few &#34;realistic&#34; features of the magnetic field

A. Kirchberg, J. D. Laenge, A. Wipf

We consider supersymmetric quantum mechanical systems in arbitrary dimensions on curved spaces with nontrivial gauge fields. The square of the Dirac operator serves as Hamiltonian. We derive a relation between the number of supercharges that exist and restrictions on the geometry of the underlying spaces as well as the admissible gauge field configurations.

Steen H. Hansen

Galaxy clusters are not iso-thermal, and the radial temperature dependence will affect the cluster parameters derived through the observation of the Sunyaev-Zeldovich (SZ) effect. We show that the derived peculiar velocity will be systematically shifted by 10-20%. For future all-sky surveys one cannot rely on the observationally expensive X-ray observations

Chuan-Tsung Chan, Jen-Chi Lee

We derive stringy Ward identities from the decoupling of two types of zero-norm states in the old covariant first quantized (OCFQ) spectrum of open bosonic string. These Ward identities are valid to all energy and all loop orders in string perturbation theory. The high-energy limit of these stringy Ward identities can then be used to fix the proportionality

G. R. Boogaard, A. H. Verbruggen, W. Belzig, T. M. Klapwijk

We study experimentally the low temperature resistance of superconducting nanowires connected to normal metal reservoirs. We find that a substantial fraction of the nanowires is resistive, down to the lowest temperature measured, indicative of an intrinsic boundary resistance due to the Andreev-conversion of normal current to supercurrent. The results are su

E. Burgos, Horacio Ceva, R. P. J. Perazzo

We study a modification of the Evolutionary Minority Game (EMG) in which agents are placed in the nodes of a regular or a random graph. A neighborhood for each agent can thus be defined and a modification of the usual relaxation dynamics can be made in which each agent updates her decision scheme depending upon the options made in her immediate neighborhood.

David H. Adams

A dimensionally reduced expression for the QCD fermion determinant at finite temperature and chemical potential is derived which sheds light on the determinant&#39;s dependence on these quantities. This is done via a partial zeta regularisation, formally applying a general formula for the zeta-determinant of a differential operator in one variable with opera

Emmanuel Auclair, Christine Lescop

We present an alternative definition for the Goussarov--Habiro filtration of the Z-module freely generated by oriented integral homology 3-spheres, by means of Lagrangian-preserving homology handlebody replacements (LP-surgeries). Garoufalidis, Goussarov and Polyak proved that the graded space (G_n)_n associated to this filtration is generated by Jacobi diag

Tomasz Radozycki

We analyze the influence of electron-positron pairs creation on the motion of vortex lines in electromagnetic field. In our approach the electric and magnetic fields satisfy nonlinear equations derived from the Euler-Heisenberg effective Lagrangian. We show that these nonlinearities may change the evolution of vortices.

J. A. Grifols, Eduard Masso, Subhendra Mohanty

Neutrinos with non-zero magnetic moments can dissociate deuterium nuclei by a photon exchange, in addition to the weak neutral current process. We calculate the neutrino-magnetic moment induced photo-dissociation cross section of deuterium using the equivalent photon method. This process would contribute extra events to the neutral current reaction which is

Karl Svozil

The noncontextuality of quantum mechanics can be directly tested by measuring two entangled particles with more than two outcomes per particle. The two associated contexts are &#34;interlinked&#34; by common observables.

E. G. Drukarev, M. G. Ryskin, V. A. Sadovnikova, Th. Gutsche

We calculate the nucleon parameters in nuclear matter using the QCD sum rules approach in Fermi gas approximation. Terms up to 1/q^2 in the operator product expansion (OPE) are taken into account. The higher moments of the nucleon structure functions are included. The complete set of the nucleon expectation values of the four-quark operators is employed. Ear

Sebastien Peirani, Roya Mohayaee, Jose A. de Freitas Pacheco

Possible indirect detection of neutralino, through its gamma-ray annihilation product, by the forthcoming GLAST satellite from our galactic halo, M31, M87 and the dwarf galaxies Draco and Sagittarius is studied. Gamma-ray fluxes are evaluated for the two representative energy thresholds, 0.1 GeV and 1.0 GeV, at which the spatial resolution of GLAST varies co

J. M. Geremia, John K. Stockton, Hideo Mabuchi

Our 2005 Physical Review Letter entitled &#34;Suppression of Spin-Projection Noise in Broadband Atomic Magnetometry&#34; (volume 94, 203002) relied heavily in its claims of experimental quantum-limited performance on the results of a prior publication from our group [1]. In subsequent work we have determined that the results of [1] were incorrect and must th

Wei Liu, Yan Wei Jiang, Siming Liu, Vahe&#39; Petrosian

We present data analysis and interpretation of a simple X-class flare observed with RHESSI on November 3, 2003. In contrast to other X-class flares observed previously, this flare shows a very simple morphology with well defined looptop (LT) and footpoint (FP) sources. The almost monotonic upward motion of the LT source and increase in separation of the two

Hai-Yang Cheng, Chun-Khiang Chua

Exclusive radiative B decays, B to K* gamma, K_1(1270) gamma, K_1(1400) gamma and K*_2(1430) gamma, are studied in the framework of a covariant light-front quark model. The tensor form factor T_1(q^2) at q^2=0, which is relevant to the decay B to K* gamma, is found to be 0.24, substantially smaller than what expected from the conventional light-front model o

A. V. Taichenachev, A. M. Tumaikin, V. I. Yudin, G. Nienhuis

We present a complete set of analytical and invariant expressions for the steady-state density matrix of atoms in a resonant radiation field with arbitrary intensity and polarization. The field drives the closed dipole transition with arbitrary values of the angular momenta $J_{g}$ and $J_{e}$ of the ground and excited state. The steady-state density matrix

Hiroaki Yamada

Localization property in the disordered few-chain DNA systems with a long-range correlation is numerically investigated. We apply the chain system with the correlated disorder in the interchain and/or intrachain hoppings to the simple model of a double strand of DNA. Numerical results for the density of states and the Lyapunov exponent of the wave function i

Damien Calaque, Pavel Etingof

We give a review of some recent developments in the theory of tensor categories. The topics include realizability of fusion rings, Ocneanu rigidity, module categories, weak Hopf algebras, Morita theory for tensor categories, lifting theory, categorical dimensions, Frobenius- Perron dimensions, classification of tensor categories.

Harald Grosse, Raimar Wulkenhaar

We prove that the real four-dimensional Euclidean noncommutative ϕ^4-model is renormalisable to all orders in perturbation theory. Compared with the commutative case, the bare action of relevant and marginal couplings contains necessarily an additional term: an harmonic oscillator potential for the free scalar field action. This entails a modified dispersion

Gerard Duchamp, Karol A. Penson, Allan I. Solomon, Andrej Horzela

In this communication, we consider the normal ordering of sums of elements of the form (a*^r a a*^s), where a* and a are boson creation and annihilation operators. We discuss the integration of the associated one-parameter groups and their combinatorial by-products. In particular, we show how these groups can be realized as groups of substitutions with prefu

Sven Hensler, Axel Griesmaier, Jörg Werner, Axel Görlitz

We realize a combined trap for bosonic chromium 52Cr and rubidium 87Rb atoms. First experiments focus on exploring a suitable loading scheme for the combined trap and on studies of new trap loss mechanisms originating from simultaneous trapping of two species. By comparing the trap loss from the 87Rb magneto-optical trap (MOT) in absence and presence of magn

B. Aoun, M. Tarifi

We provide an introduction to Quantum Cellular Automata.

Thomas Durt

Two or more quantum systems are said to be in an entangled or non-factorisable state if their joint (supposedly pure) wave-function is not expressible as a product of individual wave functions but is instead a superposition of product states. It is only when the systems are in a factorisable state that they can be considered to be separated (in the sense of

M. Combescure, F. Gieres, M. Kibler

After recalling different formulations of the definition of supersymmetric quantum mechanics given in the literature, we discuss the relationships between them in order to provide an answer to the question raised in the title.

Karol Zyczkowski, Ingemar Bengtsson

We investigate the space of quantum operations, as well as the larger space of maps which are positive, but not completely positive. A constructive criterion for decomposability is presented. A certain class of unistochastic operations, determined by unitary matrices of extended dimensionality, is defined and analyzed. Using the concept of the dynamical matr

Florian Hulpke, Dagmar Bruss, Maciej Lewenstein, Anna Sanpera

We apply the generalised concept of witness operators to arbitrary convex sets, and review the criteria for the optimisation of these general witnesses. We then define an embedding of state vectors and operators into a higher-dimensional Hilbert space. This embedding leads to a connection between any Schmidt number witness in the original Hilbert space and a

M. O. Terra Cunha, M. C. Nemes

Two mechanisms of decoherence in ion traps are studied, specially related to the experiment [Kielpinski et al., Science 291 (2001) 1013]. Statistical hypothesis are made about the unknown variables and the expected behaviour of the visibility of the best experimental pattern is calculated for each mechanism. Data from the experiment are analyzed and show to

Saugata Ghosh

We investigate the ground state properties of a family of $N$-body systems in 1-dimension, trapped in a polynomial potential and having long range 2-body interaction in addition to the inverse square potential studied in the Calogero-Sutherland model (CSM). We show that for such a Hamiltonian, the ground state energy is similar to that of free fermions in a

Alberto Barchielli, Giancarlo Lupieri

In this paper we will give a short presentation of the quantum Levy-Khinchin formula and of the formulation of quantum continual measurements based on stochastic differential equations, matters which we had the pleasure to work on in collaboration with Prof. Holevo. Then we will begin the study of various entropies and relative entropies, which seem to be pr

Luigi Accardi, Masanori Ohya

We propose a new approach to solve an NP complete problem by means of stochastic limit.

De-Zhong Cao, Zhuan Li, Yan-Hua Zhai, Kaige Wang

We theoretically discuss one-photon and two-photon double-slit interferences for spontaneous and stimulated parametric down-conversions. We show that the two-photon sub-wavelength interference can exist in a general spontaneous parametric down-conversion (SPDC) for both type I and type II crystals. We propose an alternative way to observe sub-wavelength inte

Yisroel Brumer, Eugene I. Shakhnovich

In this paper, we extend a model of host-parasite co-evolution to incorporate the semi-conservative nature of DNA replication for both the host and the parasite. We find that the optimal mutation rate for the semi-conservative and conservative hosts converge for realistic genome lengths, thus maintaining the admirable agreement between theory and experiment

Michael T. Gastner, M. E. J. Newman

Map makers have long searched for a way to construct cartograms -- maps in which the sizes of geographic regions such as countries or provinces appear in proportion to their population or some other analogous property. Such maps are invaluable for the representation of census results, election returns, disease incidence, and many other kinds of human data. U

S. Yuter, J. Koistinen, S. Di Michelle, M. Hagen

Recommendations are made for NASA/JAXA Global Precipitation Measurement (GPM) satellite Ground Validation (GV) program. This report details recommended GV site local radar products based on data from surface-based scanning radars including S-band, C-band, and X-band polarimetric and non-polarimetric radars. Three general categories of products are described:

Roberto D&#39;Autilia

We propose the use of a self-oscillating dynamical system --the pre-Galileian clock equation-- for modeling the laryngeal tone. The parameters are shown to be the minimal control needed for generating the prosody of the human speech. Based on this model, we outline a peak delay detection algorithm for extracting the prosody of the real speech.

Richard Taillet, Pierre Salati, David Maurin, Eric Pilon

Different approaches are presented to investigate diffusion from a point source in a slab delimited by two absorbing boundaries consisting of parallel infinite planes. These approaches enable to consider the effect of absorption at the boundaries as well as the possibility that the particles that diffuse react with the diffusive medium.

L. P. Horwitz, N. Katz, O. Oron

We review the formulation of the problem of the electromagnetic self-interaction of a relativistic charged particle in the framework of the manifestly covariant classical mechanics of Stueckelberg, Horwitz and Piron. The gauge fields of this theory, in general, cause the mass of the particle to change. We show that the non-linear Lorentz force equation for t

Armand Wirgin, J. -P. Groby

We show, essentially by theoretical means, that for a site with the chosen simple geometry and mechanical properties (horizontal, homogeneous, soft viscoelastic layer of infinite lateral extent overlying, and in welded contact with, a homogeneous, hard elastic substratum of half-infinite radial extent, shear-horizontal motion): 1) coupling to Love modes is a

K. Rytkonen, J. Akola, M. Manninen

Sodium atoms and clusters (N<5) on graphite (0001) are studied using density functional theory, pseudopotentials and periodic boundary conditions. A single Na atom is observed to bind at a hollow site 2.45 A above the surface with an adsorption energy of 0.51 eV. The small diffusion barrier of 0.06 eV indicates a flat potential energy surface. Increased Na c

H. Yamaguchi, R. S. Hayano, T. Ishikawa, J. Sakaguchi

A systematic study of the decay rates of antiprotonic helium (\pbhef and \pbhet) at CERN AD (Antiproton Decelerator) has been made by a laser spectroscopic method. The decay rates of some of its short-lived states, namely those for which the Auger rates $γ_{\mathrm{A}}$ are much larger than their radiative decay rates ($γ_{\mathrm{rad}} \sim 1$ $μ$s$^{-1}$),

R. Delgado-Buscalioni, P. V. Coveney

We describe recent developments in the hybrid atomistic/continuum modelling of dense fluids. We discuss the general implementation of mass, momentum and energy transfers between a region described by molecular dynamics and the neighbouring domain described by the Navier-Stokes equations for unsteady flow. The effect of fluctuations from the particle system i

G. Sardin

The cause for first and second order electromagnetic equivalency of inertial systems is approached from a different point of view than that of special relativity. While special relativity applies dilatation to time and contraction to space itself, the proposed framework applies restrictively these effects to the units of space and time, embodied in the beam

V. Hnizdo

The Coulomb-gauge vector potential of a uniformly moving point charge is obtained by calculating the gauge function for the transformation between the Lorenz and Coulomb gauges. The expression obtained for the difference between the vector potentials in the two gauges is shown to satisfy a Poisson equation to which the inhomogeneous wave equation for this qu

P. Lava, M. C. Martinez, J. Ryckebusch, J. A. Caballero

Relativistic and unfactorized calculations for the nuclear transparency extracted from exclusive A(e,e&#39;p) reactions for 0.3 \leq Q^2 \leq 10 (GeV/c)^2 are presented for the target nuclei C, Si, Fe and Pb. For Q^2 \geq 0.6 (GeV/c)^2, the transparency results are computed within the framework of the recently developed relativistic multiple-scattering Glaub

Christian Rummel, Helmut Hofmann

A method is presented which allows one to introduce collective coordinates self-consistently, in distinction to the Caldeira-Leggett model. It is demonstrated how the partition function Z for the total nuclear system can be calculated to deduce information both on its level density as well as on the decay rate of unstable modes. For the evaluation of Z diffe

V. K. B. Kota

Random one plus two-body hamiltonians invariant with respect to $O({\cal N}_1) \oplus O({\cal N}_2)$ symmetry in the group-subgroup chains $U({\cal N}) \supset U({\cal N}_1) \oplus U({\cal N}_2) \supset O({\cal N}_1) \oplus O({\cal N}_2)$ and $U({\cal N}) \supset O({\cal N}) \supset O({\cal N}_1) \oplus O({\cal N}_2)$ chains of a variety of interacting boson

V. I. Tretyak, V. Yu. Denisov, Yu. G. Zdesenko

Data of the radiochemical experiment [E.L.Fireman, 1978] with 1.7 t of KC_2H_3O_2, accumulated deep underground during ~1 yr, were reanalyzed to set limits on di-nucleons (nn and np) decays into invisible channels (disappearance, decay into neutrinos, etc.). The obtained lifetime bounds tau_np > 2.1 10^25 yr and tau_nn > 4.2 10^25 yr (at 90% C.L.) are better

Olaf Lechtenfeld, Alexander S. Sorin

We extend the Sato equations of the N=(1|1) supersymmetric Toda lattice hierarchy by two new infinite series of fermionic flows and demonstrate that the algebra of the flows of the extended hierarchy is the Borel subalgebra of the N=(2|2) loop superalgebra.

I. T. Habibullin

A method of looking for boundary conditions consistent with the integrability property of multidimensional Kadomtsev-Petviashvili (KP) type equations is discussed. The method is based on involutions of the Lax pair taken at the border plane. New classes of boundary conditions for the KP and Hirota equations are proposed consistent with the Lax pair. The boun

H. Sakaguchi, M. Tamura

Soliton motion in some external potentials is studied using the nonlinear Schrödinger equation. Solitons are scattered by a potential wall. Solitons propagate almost freely or are trapped in a periodic potential. The critical kinetic energy for reflection and trapping is evaluated approximately with a variational method.

M. T. Batchelor, R. V. Burne, B. I. Henry, M. J. Jackson

Mathematical models have recently been used to cast doubt on the biotic origin of stromatolites. Here by contrast we propose a biotic model for stromatolite morphogenesis which considers the relationship between upward growth of a phototropic or phototactic biofilm ($v$) and mineral accretion normal to the surface ($λ$). These processes are sufficient to acc

Steven H. Simon, Aris L. Moustakas

Using a character expansion method, we calculate exactly the eigenvalue density of random matrices of the form M^\dagger M where M is a complex matrix drawn from a normalized distribution P(M) ~ exp(-\Tr(A M B M^\dagger) with A and B positive definite (square) matrices of arbitrary dimensions. Such so-called ``correlated Wishart matrices&#39;&#39; occur in m

Richard P. Kent

We answer a question due to A. Myasnikov by proving that all expected ranks occur as the ranks of intersections of finitely generated subgroups of free groups.

David Helm

By the Jacquet-Langlands correspondence and Faltings&#39; isogeny theorem, it is known that the abelian variety J_0^{Dpq}(N) (the Jacobian of a Shimura curve of discriminant Dpq with Gamma_0(N) level structure) is isogenous to the pq-new subvariety of J_0^D(pqN), whenever p and q are distinct primes not dividing D or N. However, this approach is entirely non

Steven R. Bell

It is proved that quadrature domains are ubiquitous in a very strong sense in the realm of smoothly bounded multiply connected domains in the plane. In fact, they are so dense that one might as well assume that any given smooth domain one is dealing with is a quadrature domain, and this allows access to a host of strong conditions on the classical kernel fun

V. Bavula

For central simple finitely generated algebras of finite Gelfand-Kirillov dimension and for their division algebras upper bounds are obtained for the transcendence degree of their commutative subalgebras and subfields respectively. In the formulae for the upper bounds are used only two dimensions of the algebras: the Gelfand-Kirillov and the filter dimension

Ernie Croot

In this paper we give a very elementary proof that if A and B are subsets of {1,2,...,N}, each having at least 5N^{1 - (4(k-1))^{-1}} elements, then the sumset A+B has a k-term arithmetic progression.

Oliver Baues

We give a new proof that compact infra-solvmanifolds with isomorphic fundamental groups are smoothly diffeomorphic. More generally, we prove rigidity results for manifolds which are constructed using affine actions of virtually polycyclic groups on solvable Lie groups. Our results are derived from rigidity properties of subgroups in solvable linear algebraic

Andreas Wannebo

This a very brief account of the main line of development of Hardy inequalities.

Alessandra Sarti

In these notes we investigate the rings of real polynomials in four variables, which are invariant under the action of the reflectiongroups [3,4,3] and [3,3,5]. It is well known that they are rationally generated in degree 2,6,8,12 and 2,12,20,30. We give a different proof of this fact by giving explicit equations for the generating polynomials.

Andreas Wannebo

The previous &#34;Polynomial Capacities, Poincare&#39; type inequalities and Spectral synthesis in Sobolev space&#34; is a prerequisite. A parallell reading is recommended.

Francois Berteloot, Christophe Dupont

Let f an holomorphic endomorphism of CP(k) with degree larger than 2. We show that if the Green measure of f is not singular, then f is rigid : it is a Lattes example. The proof relies on a linearization property of the iterates of f, along typical orbits. This property allow us to regularize the Green current, and to prove the rigidity. -- -- -- Soit f un e

Laura Wisewell

We generalise a result of Sawyer to show the following: For each y\in R^p and w\in R^q let Γ(y,w) be a measurable d-dimensional surface in R^n. Under conditions on the number of parameters and smoothness assumptions, there exists a set of measure zero that includes a Γ(y,w) for every y.