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May 2004 arXiv papers — page 4

Showing 301–400 of 3,523 papers

  1. Jonathan R Gair, Leor Barack, Teviet Creighton, Curt Cutler

    One of the most exciting prospects for the LISA gravitational wave observatory is the detection of gravitational radiation from the inspiral of a compact object into a supermassive black hole. The large inspiral parameter space and low amplitude of the signal makes detection of these sources computationally challenging. We outline here a first cut data analy

  2. B. S. Sathyaprakash

    Astronomical observations in the electromagnetic window - microwave, radio and optical - have revealed that most of the Universe is dark. The only reason we know that dark matter exists is because of its gravitational influence on luminous matter. It is plausible that a small fraction of that dark matter is clumped, and strongly gravitating. Such systems are

  3. Gopal Ananthraman

    Consider the commonly known puzzle, given $k$ glass balls, find an optimal algorithm to determine the lowest floor of a building of $n$ floors from which a thrown glass ball will break. This puzzle was originally posed in its original form in \cite{focs1980}and was later cited in the book \cite{algthc}. There are several internet sites that presents this puz

  4. Allison Woodruff, Paul M. Aoki

    We provide two case studies in the application of ideas drawn from conversation analysis to the design of technologies that enhance the experience of human conversation. We first present a case study of the design of an electronic guidebook, focusing on how conversation analytic principles played a role in the design process. We then discuss how the guideboo

  5. Paul M. Aoki, Allison Woodruff

    In current presence or availability systems, the method of presenting a user's state often supposes an instantaneous notion of that state - for example, a visualization is rendered or an inference is made about the potential actions that might be consistent with a user's state. Drawing on observational research on the use of existing communication te

  6. Sergio Alejandro Gomez, Carlos Ivan Chesñevar

    The field of machine learning (ML) is concerned with the question of how to construct algorithms that automatically improve with experience. In recent years many successful ML applications have been developed, such as datamining programs, information-filtering systems, etc. Although ML algorithms allow the detection and extraction of interesting patterns of

  7. A. A. Clerk, S. M. Girvin

    We study quantum-mechanically the frequency-dependent current noise of a tunnel-junction coupled to a nanomechanical oscillator. The cases of both DC and AC voltage bias are considered, as are the effects of intrinsic oscillator damping. The dynamics of the oscillator can lead to large signatures in the shot noise, even if the oscillator-tunnel junction coup

  8. Friederike Schmid, Dominik Düchs, Olaf Lenz, Claire Loison

    Computer simulations of coarse-grained molecular models for amphiphilic systems can provide insight into the the structure of amphiphiles at interfaces. They can help to identify the factors that determine the phase behavior, and they can bridge between atomic descriptions and phenomenological field theories. Here we focus on model systems for amphiphilic me

  9. W. Yu, F. Zhang, F. Zamborszky, B. Alavi

    (TMTTF)$_2$SbF$_6$ is known to undergo a charge ordering (CO) phase transition at $T_{CO}\approx156K$ and another transition to an antiferromagnetic (AF) state at $T_N\approx 8K$. Applied pressure $P$ causes a decrease in both $T_{CO}$ and $T_N$. When $P>0.5 GPa$, the CO is largely supressed, and there is no remaining signature of AF order. Instead, the grou

  10. David Cheung, Friederike Schmid

    A system of soft ellipsoid molecules confined between two planar walls is studied using classical Density Functional Theory (DFT). Both the isotropic and nematic phases are considered. The excess free energy is evaluated using two different Ansaetze and the intermolecular interaction is incorporated using two different direct correlation functions (DCF). The

  11. Vladimir A. Fonoberov, Alexander A. Balandin

    We derive within the dielectric-continuum model an integral equation that defines interface and confined polar optical-phonon modes in nanocrystals with wurtzite crystal structure. It is demonstrated theoretically, that while the frequency of confined polar optical phonons in zincblende nanocrystals is equal to that of the bulk crystal phonons, the confined

  12. C. J. Tymczak, Matt Challacombe

    Linear scaling quantum chemical methods for Density Functional Theory are extended to the condensed phase at the $Γ$-point. For the two-electron Coulomb matrix, this is achieved with a tree-code algorithm for fast Coulomb summation [J. Chem. Phys. {\bf 106}, 5526 (1997)], together with multipole representation of the crystal field [J. Chem. Phys. {\bf 107},

  13. Q. Huang, B. Khaykovich, F. C. Chou, J. H. Cho

    We report neutron powder diffraction measurements on a series of NaxCoO2 samples with x near 0.75 which were prepared under different synthesis conditions. Two different crystal structures for the samples are observed at room temperature. The two structures differ primarily by a shift of a large fraction of the Na ions from a high-symmetry position to a lowe

  14. M. Persson

    We have carried out a density functional study of unoccupied, resonance states in a single Au atom, dimers, a trimer and infinite Au chains on the NiAl(110) surface. Two inequivalent orientations of the ad-chains with substantially different interatomic distances were considered. From the study of the evolution of the electron states in an Au chain from bein

  15. Fatkhulla Kh. Abdullaev, Ravil M. Galimzyanov, Marijana Brtka, Roberto A. Kraenkel

    Nonlinear oscillations of a 3D radial symmetric Bose-Einstein condensate under periodic variation in time of the atomic scattering length have been studied analytically and numerically. The time-dependent variational approach is used for the analysis of the characteristics of nonlinear resonances in the oscillations of the condensate. The bistability in osci

  16. F. Siano, R. Egger

    We present theoretical results for the equilibrium Josephson current through an Anderson dot tuned into the magnetic regime, using Hirsch-Fye Monte Carlo simulations covering the complete crossover from Kondo-dominated physics to $π$ junction behavior in a numerically exact way. Within the `magnetic' regime, $U/Γ\gg 1$ and $ε_0/Γ\leq 1$, the Josephson cu

  17. F. Karimi Pour Haddadan, F. Schlesener, S. Dietrich

    We consider a nematic liquid crystal confined by two parallel planar interfaces, one being laterally homogeneous and the other provided by a substrate endowed with a periodic chemical stripe pattern. Based on continuum theory we analyze the influence of the lateral pattern on the liquid-crystalline Casimir force acting on the interfaces of the nematic cell a

  18. Cecile Veauvy, Klaus Hasselbach, Dominique Mailly

    A scanning micro superconducting quantum interference device (microSQUID) microscope is used to directly image vortices in a superconducting Al thin film. We observe the temperature dependence of the vortex distribution in a regular defect (hole) array patterned into the Al film. The first direct observation of the localized superconducting state around the

  19. A. J. Archer, R. Evans

    We present an alternative derivation of the dynamical density functional theory for the one body density profile of a classical fluid developed by Marconi and Tarazona [J. Chem. Phys., 110, 8032 (1999)]. Our derivation elucidates further some of the physical assumptions inherent in the theory and shows that it is not restricted to fluids composed of particle

  20. K. Kakuyanagi, M. Saito, K. Kumagai, S. Takashina

    We present a ^{115}In NMR study of the quasi two-dimensional heavy-fermion superconductor CeCoIn_5 believed to host a Fulde-Ferrel-Larkin-Ovchinnkov (FFLO) state. In the vicinity of the upper critical field and with a magnetic field applied parallel to the ab-plane, the NMR spectrum exhibits a dramatic change below T*(H) which well coincides with the positio

  21. Yuriy V. Pershin

    We develop a drift-diffusion equation that describes electron spin polarization density in two-dimensional electron systems. In our approach, superpositions of spin-up and spin-down states are taken into account, what distinguishes our model from the traditional two-component drift-diffusion approximation. The Dresselhaus and Rashba spin-orbit coupling mecha

  22. F. Slanina, H. Lavicka

    The Sznajd model, which describes opinion formation and social influence, is treated analytically on a complete graph. We prove the existence of the phase transition in the original formulation of the model, while for the Ochrombel modification we find smooth behaviour without transition. We calculate the average time to reach the stationary state as well as

  23. H. Freire, E. Correa, A. Ferraz

    In the present work, we implement an explicit two-loop renormalization of a two-dimensional flat Fermi surface (FS) in the framework of a field theoretical renormalization group approach (RG). In our scheme, we derive the RG equations for both the coupling functions and Fermi energy. In this way, we are able to probe the existence of spin-charge separation b

  24. Seb Oliver, Ian Waddington, Eduardo Gonzalez-Solares, Jason Surace

    We present the first analysis of large-scale clustering from the Spitzer Wide-area InfraRed Extragalactic legacy survey: SWIRE. We compute the angular correlation function of galaxies selected to have 3.6 micron fluxes brighter than 32 muJy in three fields totaling two square degrees in area. In each field we detect clustering with a high level of significan

  25. Anjum S. Mukadam, D. E. Winget, Ted von Hippel, M. H. Montgomery

    We use the new ZZ Ceti stars (hydrogen atmosphere white dwarf variables; DAVs) discovered within the Sloan Digital Sky Survey (Mukadam et al. 2004) to re-define the empirical ZZ Ceti instability strip. This is the first time since the discovery of white dwarf variables in 1968 that we have a homogeneous set of spectra acquired using the same instrument on th

  26. Jun Pan, Istvan Szapudi

    Conditional cumulants form a set of unique statistics which represent a sensible compromise between N-point correlation functions and cumulants measured from moments of counts in cells. They share accurate edge corrected estimators with $N$-point correlation functions, yet, they are as straightforward to measure and interpret as counts in cells. The conditio

  27. Keith A. Olive, Evan D. Skillman

    Currently there are two significantly different observational determinations of the primordial helium abundance, and, if only statistical errors in He4 abundance determinations are considered, the discrepancies between the observational determinations and the value favored by the WMAP results are significant. Here we examine in detail some likely sources of

  28. Nancy Remage Evans, Eric M. Schlegel, Wayne L. Waldron, Frederick D. Seward

    The low resolution X-ray spectra around $η$ Car covering Tr 16 and part of Tr 14 have been extracted from a Chandra CCD ACIS image. Various analysis techniques have been applied to the spectra based on their count rates. The spectra with the greatest number of counts (HD 93162 = WR 25, HD 93129AB, and HD 93250) have been fit with a wind model, which uses sev

  29. M. Emprechtinger, T. Forveille, S. Kimeswenger

    We present a spectroscopic investigation of two hitherto unstudied galactic planetary nebulae (MeWe 1-10 and MeWe 1-11) and one candidate object (MeWe 2-5). The candidate object clearly has been identified as a bipolar hourglass shaped PN. The galactic foreground extinction was derived and using photoionization models with CLOUDY the two round objects were c

  30. M. Viel, M. Haehnelt, T. -S. Kim, B. Carswell

    We use the LUQAS sample of 27 high resolution, high signal-to-noise QSO absorption spectra (Kim et al. 2004) and the results from Croft et al. (2002) together with a suite of high-resolution hydro-dynamical simulations run with the GADGET-II code, to infer the linear dark matter power spectrum on scales of \~ 0.3-30 Mpc at z=2.125 and at z=2.72.

  31. W. Gieren, G. Pietrzynski, A. Walker, F. Bresolin

    In a previous paper, we reported on the discovery of more than a hundred new Cepheid variables in the Sculptor Group spiral NGC 300 from wide-field images taken in the B and V photometric bands at ESO/La Silla. In this paper, we present additional VI data, derive improved periods and mean magnitudes for the variables, and construct period-luminosity relation

  32. A. Maggio, J. J. Drake, V. Kashyap, F. R. Harnden,

    We present the analysis and interpretation of an observation of the flare star AD Leo (dM3e) with Chandra/LETG. The high resolution X-ray spectrum allowed us to infer the plasma emission measure distribution (EMD) vs. temperature, and the abundances of individual elements in the corona of this magnetically-active star, during a typical state characterized by

  33. Bruce G. Elmegreen

    Turbulence, self-gravity, and cooling convert most of the interstellar medium into cloudy structures that form stars. Turbulence compresses the gas into clouds directly and it moves pre-existing clouds around passively when there are multiple phases of temperature. Self-gravity also partitions the gas into clouds, forming giant regular complexes in spiral ar

  34. Sylvain Chaty, Philippe Filliatre

    The X-ray source IGR J16318-4848 was the first source discovered by INTEGRAL on 2003, January 29. The high energy spectrum exhibits such a high column density that the source is undetectable in X-rays below 2 keV. On 2003, February, 23--25 we triggered a Target of Opportunity (ToO) program using the EMMI and SOFI instruments on the New Technology Telescope o

  35. W. Domainko, W. Kapferer, S. Schindler, E. van Kampen

    We present numerical simulations of the dynamical and chemical evolution of galaxy clusters. X-ray spectra show that the intra-cluster medium contains a significant amount of metals. As heavy elements are produced in the stars of galaxies material from the galaxies must have been expelled to enrich the ambient medium. We have performed hydrodynamic simulatio

  36. W. Kapferer, D. Breitschwerdt, W. Domainko, S. Schindler

    We investigate efficiency and time dependence of metal enrichment processes in the Intra-Cluster Medium (ICM). In this presentation we concentrate on the effects of galactic winds. The mass loss rates due to galactic winds are calculated with a special algorithm, which takes into account cosmic rays and magnetic fields. This algorithm is embedded in a combin

  37. S. Andreon, J. Willis, H. Quintana, I. Valtchanov

    We present first results on the use of a colour space filter for detecting galaxy clusters at cosmological redshifts in the XMM Large Scale Structure Survey. All clusters studied, but one, are successfully colour--detected in spite of their large redshift (0.3<z<1.0), X-ray selection and intrinsic low richness (R=0 or below). We experimentally show that the

  38. P. A. Evans, Coel Hellier

    V405 Aurigae is an intermediate polar showing a double-peaked pulsation in soft X-rays and a single-peaked pulsation in harder X-rays. From XMM-Newton observations we find that the soft band is dominated by blackbody emission from the heated white-dwarf surface. Such emission is at a maximum when either magnetic pole points towards us, explaining the double-

  39. P. S. Negi

    Spiral galaxies are considered as static, spherically symmetric Dark Matter Configurations (DMC)in which non-zero rest-mass particles (NZRPs) move along appropriate trajectories. Using general relativity (GR), we show that a mass of dark matter about 127 - 212 $\times 10^{11} M_{\odot}$ is required inside the sphere of size $a \sim 10 $ kpc for agreement wit

  40. N. A. Webb, D. Serre, B. Gendre, D. Barret

    Using XMM-Newton EPIC imaging data, we have detected 50 low-luminosity X-ray sources in the field of view of M 22, where 5 +/- 3 of these sources are likely to be related to the cluster. Using differential optical photometry, we have identified probable counterparts to those sources belonging to the cluster. Using X-ray spectroscopic and timing studies, supp

  41. A. K. Turner, A. C. Fabian, J. C. Lee, S. Vaughan

    The absorption lines in the soft X-ray spectrum of MCG--6-30-15 are studied using the Reflection Grating Spectrometer data from the 2001 XMM-Newton 320 ks observation. A line search of the full time-averaged spectrum reveals 51 absorption lines and one emission line. The equivalent widths of the lines are measured and the majority of the lines identified. We

  42. D. Giannios, N. D. Kylafis, D. Psaltis

    we propose a jet model for the low/hard state of black-hole X-ray sources which explains a) the X-ray spectra, b) the timelag spectra, c) the increase in the amplitude (QPO and high frequency) with increasing photon energy, and d) the narrowing of the autocorrelation function with increasing photon energy. The model (in its simplest form) assumes that i) the

  43. A. Ray

    Atomic nuclei are transformed into each other in the cosmos by nuclear reactions inside stars: -- the process of nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars and how they manage to burn their fuel so slowly most of the time are discussed. Thermonuclear reactions involving protons in the hydrostatic burning of hydroge

  44. Evalyn Gates, Geza Gyuk, Hugh C. Harris, Mark Subbarao

    We report the discovery of five very cool white dwarfs in the Sloan Digital Sky Survey (SDSS). Four are ultracool, exhibiting strong collision induced absorption (CIA) from molecular hydrogen and are similar in color to the three previously known coolest white dwarfs, SDSS J1337+00, LHS 3250 and LHS 1402. The fifth, an ultracool white dwarf candidate, shows

  45. Blake Mellor

    In previous work, the author defined the intersection graph of a chord diagram associated with string links (as in the theory of finite type invariants). In this paper, we classify the trees which can be obtained as intersection graphs of string link diagrams.

  46. Michiel Reuland, Huub Roettgering, Wil van Breugel, Carlos De Breuck

    We present the results of an observing program with the SCUBA bolometer array to measure the submillimetre (submm) dust continuum emission of 24 distant (z > 1) radio galaxies. We detected submm emission in 12 galaxies with S/N > 3, including 9 detections at z > 3. When added to previous published results these data almost triple the number of radio galaxies

  47. The MILC Collaboration, C. Bernard, T. Burch, C. DeTar

    We report on a study of QCD thermodynamics with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad O(a^2) improved staggered quark action. Simulations were carried out with lattice spacings 1/4T, 1/6T and 1/8T both for three degenerate quarks with masses less than or equal to the strange quark mass, m_s, and for degenerate up and

  48. Ulrich D. Jentschura, Jean Zinn-Justin

    Certain quantum mechanical potentials give rise to a vanishing perturbation series for at least one energy level (which as we here assume is the ground state), but the true ground-state energy is positive. We show here that in a typical case, the eigenvalue may be expressed in terms of a generalized perturbative expansion (resurgent expansion). Modified Bohr

  49. Taotao Fang, Renyue Cen

    The transition from Population III to Population II stars is determined by the presence of a sufficient amount of metals, in particular, oxygen and carbon. The vastly different yields of these relevant metals between different initial stellar mass functions would then cause such a transition to occur at different times. We show that the transition from Pop I

  50. Chisato Yamauchi, Tomotsugu Goto

    Passive spiral galaxies -- unusual galaxies with spiral morphology without any sign of on-going star formation -- have recently been discovered to exist preferentially in cluster infalling regions (at about the virial radius, or at a local galaxy density of $\sim 1$ Mpc$^{-2}$). The discovery directly connects the passive spiral galaxies to the cluster galax

  51. R. L. Kozub, D. W. Bardayan, J. C. Batchelder, J. C. Blackmon

    The degree to which the (p,gamma) and (p,alpha) reactions destroy 18F at temperatures 1-4x10^8 K is important for understanding the synthesis of nuclei in nova explosions and for using the long-lived radionuclide 18F, a target of gamma-ray astronomy, as a diagnostic of nova mechanisms. The reactions are dominated by low-lying proton resonances near the 18F+p

  52. Guenter Sigl

    We investigate the dependence of composition, spectrum and angular distributions of ultra-high energy cosmic rays above 10^19 eV from individual sources on their magnetization. We find that, especially for sources within a few megaparsecs from the observer, observable spectra and composition are severely modified if the source is surrounded by fields of ~ 10

  53. Boris D. Lubachevsky, Frank H. Stillinger

    We use numerical simulation to investigate and analyze the way that rigid disks and spheres arrange themselves when compressed next to incommensurate substrates. For disks, a movable set is pressed into a jammed state against an ordered fixed line of larger disks, where the diameter ratio of movable to fixed disks is 0.8. The corresponding diameter ratio for

  54. Daniel L. Nedel, M. C. B. Abdalla, A. L. Gadelha

    A thermodynamical analysis for the type IIB superstring in a pp-wave background is considered. The thermal Fock space is built and the temperature SUSY breaking appears naturally by analyzing the thermal vacuum. All the thermodynamical quantities are derived by evaluating matrix elements of operators in the thermal Fock space. This approach seems to be suita

  55. Jorgen Rasmussen

    It is discussed how a limiting procedure of (super)conformal field theories may result in logarithmic (super)conformal field theories. The construction is illustrated by logarithmic limits of (unitary) minimal models in conformal field theory and in N=1 superconformal field theory.

  56. M. Modugno, C. Tozzo, F. Dalfovo

    The occurrence of energetic and dynamical instabilities in a Bose-Einstein condensate moving in a one-dimensional (1D) optical lattice is analyzed by means of the Gross-Pitaevskii theory. Results of full 3D calculations are compared with those of an effective 1D model, the nonpolynomial Schrodinger equation, pointing out the role played by transverse degrees

  57. Jailton C. Ferreira

    A proof of the Riemann hypothesis using the reflection principle is presented.

  58. Lukas Saul, Eberhard Moebius, Charles W. Smith

    Pickup ion distributions vary substantially on a variety of time scales, although their sources may be relatively steady. This complicates their use as probes of the heliospheric and local interstellar particle populations. Interstellar He+ pickup ion observations from SOHO/CTOF and measurements of interplanetary conditions from SOHO and WIND enable a quanti

  59. Hiroki Nagahara, Takatoshi Ichino, Kenichi Yoshikawa

    Living organisms process information without any central control unit and without any ruling clock. We have been studying a novel computational strategy that uses a geometrically arranged excitable field, i.e., &#34;field computation.&#34; As an extension of this research, in the present article we report the construction of a &#34;direction detector&#34; on

  60. C. Pena, S. Sint, A. Vladikas

    Twisted mass lattice QCD (tmQCD), generalised to four Wilson quark flavours, can be used for the computation of some weak matrix elements related to $ΔI=1/2$ transitions. Besides eliminating unphysical zero modes, tmQCD may alleviate long-standing renormalisation problems of the four-quark operators which contribute to CP-conserving $K\toπ$ transitions. With

  61. J. González-Nuevo, L. Toffolatti, F. Argüeso

    We present predictions on the angular power spectrum of CMB fluctuations due to extragalactic point sources (EPS) by using a method for simulating realistic 2D distributions of clustered EPS. Both radio and far--IR selected source populations are taken into account. To analyze different clustering scenarios, we exploit angular power spectra of EPS, $P(k)$, e

  62. S. Ramgoolam, B. Spence, S. Thomas

    A collapsing spherical D2-brane carrying magnetic flux can be described in the region of small radius in a dual zero-brane picture using Tseytlin&#39;s proposal for a non-Abelian Dirac-Born-Infeld action for N D0-branes. A standard large N approximation of the D0-brane action, familiar from the brane dielectric effect, gives a time evolution which agrees wit

  63. F. Vazquez, S. Redner

    We determine the ultimate fate of individual opinions in a socially-interacting population of leftists, centrists, and rightists. In an elemental interaction between agents, a centrist and a leftist can become both centrists or both become leftists with equal rates (and similarly for a centrist and a rightist). However leftists and rightists do not interact.

  64. Yves Brihaye, Eugen Radu, D. H. Tchrakian

    We construct both regular and black hole spherically symmetric solutions to the original higher curvature EYM model augmented by a Grassmannian sigma model field in $d=5$ spacetime dimensions. Unlike the original model, the new model supports regular solutions in the flat space limit. We find that a peculiar singular behaviour of the solutions in the origina

  65. J. Armenta, J. A. Nieto

    We discuss the relativistic top theory from the point of view of the de Sitter (or anti de Sitter) group. Our treatment rests on Hanson-Regge&#39;s spherical relativistic top lagrangian formulation. We propose an alternative method for studying spinning objects via Kaluza-Klein theory. In particular, we derive the relativistic top equations of motion startin

  66. A. N. Gorban, A. Yu. Zinovyev

    Principal manifolds serve as useful tool for many practical applications. These manifolds are defined as lines or surfaces passing through &#34;the middle&#34; of data distribution. We propose an algorithm for fast construction of grid approximations of principal manifolds with given topology. It is based on analogy of principal manifold and elastic membrane

  67. Stephen Whitelam, Juan P. Garrahan

    We use a real-space renormalization group (RSRG) to study the low temperature dynamics of kinetically constrained Ising chains (KCICs). We consider the cases of the Fredrickson-Andersen (FA) model, the East model, and the partially asymmetric KCIC. We show that the RSRG allows one to obtain in a unified manner the dynamical properties of these models near th

  68. Denis Gialis, Guy Pelletier

    The paper is devoted to the analysis of particle acceleration in Gamma-Ray Bursts and its radiative consequences. Therefore we get on one hand constraints on the physics and on the other hand possible signatures of particle acceleration that could be recorded by the new gamma ray instruments. We have previously shown that UHECRs can be generated in GRBs even

  69. R. Bonciani, A. Ferroglia, P. Mastrolia, E. Remiddi

    We calculate the two-loop virtual, UV renormalized corrections at order α^4 (N_F=1) in QED to the Bhabha scattering differential cross section, for arbitrary values of the squared c.m. energy s and momentum transfer t, and on-shell electrons and positrons of finite mass m. The calculation is carried out within the dimensional regularization scheme; the remai

  70. Yevgeny Kats, Isaschar Genish, Lior Klein, James W. Reiner

    Recently it has been suggested that the complicated temperature dependence of the extraordinary Hall effect (EHE) in the itinerant ferromagnet SrRuO3 could be explained by the Berry phase effect in the crystal momentum space. We test this model by measurements of EHE as a function of an applied magnetic field at a constant temperature and show that the resul

  71. Nazim A. Fates, Michel Morvan

    An experimental analysis of the asynchronous version of the &#34;Game of Life&#34; is performed to estimate how topology perturbations modify its evolution. We focus on the study of a phase transition from an &#34;inactive-sparse phase&#34; to a &#34;labyrinth phase&#34; and produce experimental data to quantify these changes as a function of the density of

  72. M. Guagnelli, K. Jansen, F. Palombi, R. Petronzio

    We give a continuum limit value of the lowest moment of a twist-2 operator in pion states from non-perturbative lattice calculations. We find that the non-perturbatively obtained renormalization group invariant matrix element is <x>_{RGI} = 0.179(11), which corresponds to <x>^{MSbar}(2 GeV) = 0.246(15). In obtaining the renormalization group invariant matrix

  73. A. Ya. Maltsev

    We consider the special type of the field-theoretical Symplectic structures called weakly nonlocal. The structures of this type are in particular very common for the integrable systems like KdV or NLS. We introduce here the special class of the weakly nonlocal Symplectic structures which we call the weakly nonlocal Symplectic structures of Hydrodynamic Type.

  74. E. V. Sampathkumaran, N. Fujiwara, S. Rayaprol, P. K. Madhu

    We have performed field-swept 59Co NMR measurements on the &#39;exotic&#39; spin-chain material, Ca3Co2O6, crystallizing in K4CdCl6-type rhombohedral structure, believed to exhibit two magnetic transition temperatures (around 24 and 12 K). This is the first NMR investigation of this family of compounds. We are able to detect the NMR signal below about 15 K,

  75. Jochen Zahn

    We study Noncommutative Electrodynamics using the concept of covariant coordinates. We propose a scheme for interpreting the formalism and construct two basic examples, a constant field and a plane wave. Superposing these two, we find a modification of the dispersion relation. Our results differ from those obtained via the Seiberg-Witten map.

  76. M. Pohlen, J. E. Beckman, S. Huettemeister, J. H. Knapen

    In the light of several recent developments we revisit the phenomenon of galactic stellar disk truncations. Even 25 years since the first paper on outer breaks in the radial light profiles of spiral galaxies, their origin is still unclear. The two most promising explanations are that these &#39;outer edges&#39; either trace the maximum angular momentum durin

  77. Sergey N. Solodukhin

    Minkowski space is a physically important space-time for which the finding an adequate holographic description is an urgent problem. In this paper we develop further the proposal made in hep-th/0303006 for the description as a duality between Minkowski space-time and a Conformal Field Theory defined on the boundary of the light-cone. We focus on the gravitat

  78. Eric Lutz

    We establish an explicit correspondence between ergodicity breaking in a system described by power-law tail distributions and the divergence of the moments of these distributions.

  79. A. Gomez Nicola, F. J. LLanes-Estrada, J. R. Pelaez

    We discuss the thermal behaviour of the pion vector form factors and calculate them in one-loop Chiral Perturbation Theory. The perturbative result is used to analyze the $T$-dependent electromagnetic pion charge radius, obtaining a rough estimate of the deconfinement critical temperature. Imposing thermal unitarity, we generate the $ρ$ resonance pole for th

  80. Stefan Antusch, S. F. King

    We review the mechanism of sequential right-handed neutrino dominance proposed in the framework of the type I see-saw mechanism to account for bi-large neutrino mixing and a neutrino mass hierarchy in a natural way. We discuss how sequential dominance may also be applied to the right-handed charged leptons, which alternatively allows bi-large lepton mixing f

  81. Masaru Onoda, Gen Tatara, Naoto Nagaosa

    We study the anomalous Hall effect (AHE) for the double exchange model with the exchange coupling $|J_H|$ being smaller than the bandwidth $|t|$ for the purpose of clarifying the following unresolved and confusing issues: (i) the effect of the underlying lattice structure, (ii) the relation between AHE and the skyrmion number, (iii) the duality between real

  82. J. Kinnunen, M. Rodriguez, P. Torma

    We consider trapped atomic Fermi gases with Feshbach-resonance enhanced interactions in pseudogap and superfluid temperatures. We calculate the spectrum of RF(or laser)-excitations for transitions that transfer atoms out of the superfluid state. The spectrum displays the pairing gap and also the contribution of unpaired atoms, i.e. in-gap excitations. The re

  83. Marc J. Kuchner

    By analogy with the minimum-mass solar nebula, we construct a surface-density profile using the orbits of the 26 precise-Doppler planets found in multiple planet systems: Sigma = 2200 grams per square centimeter (a/1 AU)^- beta, where a is the circumstellar radius, and beta = 2.0 plus or minus 0.5. The minimum-mass solar nebula is consistent with this model,

  84. Shinya Tomizawa, Yuki Uchida, Tetsuya Shiromizu

    It is unlikely that uniqueness theorem holds for stationary black holes in higher dimensional spacetimes. However, we will examine the possibility that the higher multipole moments classify vacuum solutions uniquely. Especially, we compute the potentials associated with rotational Killing vectors and look at the dependence on the total mass M and angular mom

  85. R. Albuquerque, J. Rawnsley

    This article is a contribution to the understanding of the geometry of the twistor space of a symplectic manifold. We consider the bundle $Z$ with fibre the Siegel domain Sp(2n,R)/U(n) existing over any given symplectic 2n-manifold M. Then, after recalling the construction of the almost complex structure induced on $Z$ by a symplectic connection on M, we stu

  86. Shiro Kawabata, Satoshi Kashiwaya, Yasuhiro Asano, Yukio Tanaka

    We examine the macroscopic quantum tunneling (MQT) in high-Tc superconductor Josephson junctions with a d-wave order parameter. Using microscopic Hamiltonian and the functional integral method, we analytically obtain the MQT rate (the inverse lifetime of the metastable state) for the c-axis twist Josephson junctions. In the case of the zero twist angle, the

  87. S. Iblisdir, N. Gisin

    It is pointed out that two separated quantum channels and three classical authenticated channels are sufficient resources to achieve detectable broadcast.

  88. Philipp Hyllus, Carolina Moura Alves, Dagmar Bruss, Chiara Macchiavello

    We propose a method for the experimental generation of two different families of bound entangled states of three qubits. Our method is based on the explicit construction of a quantum network that produces a purification of the desired state. We also suggest a route for the experimental detection of bound entanglement, by employing a witness operator plus a t

  89. Debashish Chowdhury, Dietrich Stauffer

    Ecology and evolution are inseparable. Motivated by some recent experiments, we have developed models of evolutionary ecology from the perspective of dynamic networks. In these models, in addition to the intra-node dynamics, which corresponds to an individual-based population dynamics of species, the entire network itself changes slowly with time to capture

  90. Dorothea Hahn, Mario Liu

    A unified, consistent and simple view of the Faraday law of induction is presented, which consists of two points: discriminating the lab- from the rest-frame electric field and understanding it is the impossibility for both fields to vanish simultaneously, which generates and maintains the circular current. A number of illustrative examples are considered, i

  91. George Sand Franca, Joaquim Mendes Ferreira, Mario Koechi Takeya

    The Tucunduba Dam is about 290 km West of Fortaleza, Ceará state. The seismic monitoring of the area, with a local network, has began on June 11, 1997, soon after the occurrence of the event with magnitude 3.2 $m_b$ on June 09, 1997. The monitoring was done with one the analogical station (used for magnitude duration measurement and statistical control activ

  92. Randall D. Peters

    Evidence is provided, from yet another experiment, for the existence of a mesoscale quantum of internal friction hysteresis, having the value of the electron rest energy divided by the fine structure constant.

  93. Valery P. Dmitriyev

    There are three electromagnetic integrals of motion that can be interpreted as the energy. These are the background energy, the elastic energy and the integral in the torsion field commonly referred to as the energy of the electromagnetic field. The integral in the torsion field gains the meaning of the energy insomuch as it is concerned with the mechanical

  94. Gustavo R. Gonzalez-Martin, Ignacio J. Taboada, Javier G. Gonzalez

    The magnetic moment of the proton is calculated using a geometric unified theory. The geometry determines a generalized Pauli equation showing anomalous terms due to the triplet proton structure. The theoretical result gives a bare anomalous Lande gyromagnetic g-factor close to the experimental value. The necessary radiative corrections should be included in

  95. Yuri A. Rylov

    The quantum mechanics is considered to be a partial case of the stochastic system dynamics. It is shown that the wave function describes the state of statistically averaged system $<\mathcal{S}_{st}>$, but not that of the individual stochastic system $\mathcal{S}_{st}$. It is a common practice to think that such a construction of quantum mechanics contains h

  96. Akito Arima

    In this talk I shall discuss the clustering aspect and the shell model. I shall first discuss the $α$-cluster aspects based on the shell model calculations. Then I shall discuss the spin zero ground state dominance in the presence of random interactions and a new type of cluster structure for fermions in a single-$j$ shell in the presence of only pairing int

  97. Robert P. Hildebrandt, Harald W. Grießhammer, Thomas R. Hemmert, Daniel R. Phillips

    We examine elastic Compton scattering off the deuteron for photon energies between 50 MeV and 100 MeV in the framework of chiral effective field theories to next-to-leading order. We compare one theoretical scheme with only pions and nucleons as explicit degrees of freedom to another in which the Delta(1232) resonance is treated as an explicit degree of free

  98. Andreas Schmitt

    In this thesis, several color-superconducting phases where quarks of the same flavor form Cooper pairs are investigated. In these phases, a Cooper pair carries total spin one. A systematic classification of theoretically possible phases, discriminated by the color-spin structure of the order parameter and the respective symmetry breaking pattern, is presente

  99. H. W. Barz, B. Kampfer, L. Naumann, Gy. Wolf

    K+, K- and ϕmeson production in proton-nucleus (pA) collisions has been calculated within a BUU transport model. It is shown that the nucleon-hyperon strangeness transfer channel is essential. The role of three-body reactions has been investigated within the medium. The targetmass dependence of $ϕ$ production is predicted to give important information on the

  100. R. Chandra, J. Singh, P. K. Rath, P. K. Raina

    The two neutrino double beta decay of $ ^{94,96}$Zr$,^{98,100}$Mo$,^{104}$% Ru and $ ^{110}$Pd nuclei for $0^{+}\to 0^{+}$ transition is studied in the PHFB model in conjunction with the summation method. In the first step, the reliability of the intrinsic wave functions has been established by obtaining an overall agreement between a number of theoretically