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November 2001 arXiv papers — page 12

Showing 1,101–1,200 of 3,154 papers

  1. Y. Nakamura, Yu. A. Pashkin, T. Yamamoto, J. S. Tsai

    A spin-echo-type technique is applied to an artificial two-level system that utilizes charge degree of freedom in a small superconducting electrode. Gate-voltage pulses are used to produce the necessary pulse sequence in order to eliminate the inhomogeneity effect in the time-ensemble measurement and to obtain refocused echo signals. Comparison of the decay

  2. M. A. Yurishchev

    A closed-form exact analytical solution for the q-state Potts model on a ladder 2 x oo with arbitrary two-, three-, and four-site interactions in a unit cell is presented. Using the obtained solution it is shown that the finite-size internal energy equation yields an accurate value of the critical temperature for the triangular Potts lattice with three-site

  3. M. A. Hein, M. Getta, S. Kreiskott, B. Moenter

    We describe and analyze selected surface impedance data recently obtained by different groups on cuprate, ruthenate and diboride superconducting films on metallic and dielectric substrates for fundamental studies and microwave applications. The discussion includes a first review of microwave data on MgB2, the weak-link behaviour of RABiTS-type YBa2Cu3O7-d ta

  4. Keigo Hijii, Kiyohide Nomura

    We study s=1/2 Heisenberg spin ladder with the four spin exchange. Combining numerical results with the conformal field theory(CFT), we find a phase transition with central charge c=3/2. Since this system has an SU(2) symmetry, we can conclude that this critical theory is described by k=2 SU(2) Wess-Zumino-Witten model with Z$_2$ symmetry breaking.

  5. Niels Asger Mortensen

    This thesis describes the merging of the two fields of Coulomb drag and mesoscopic physics. The thesis presents a theory for Coulomb drag between two mesoscopic systems based on linear-response theory. The formalism expresses the drag in terms of either scattering matrices and wave functions or Green functions, and its range of validity covers both ballistic

  6. M. Ricker, J. Bachteler, H. -R. Trebin

    In quasicrystals, there are not only conventional, but also phason displacement fields and associated Burgers vectors. We have calculated approximate solutions for the elastic fields induced by two-, three- and fivefold straight screw- and edge-dislocations in infinite icosahedral quasicrystals by means of a generalized perturbation method. Starting from the

  7. Tsunenao Kuwae, Nobuhiko Taniguchi

    When one applies a type of non-Hermitian effect, constant imaginary vector potential, to disordered systems, delocalization is induced even in two or lower dimension. By using the non-Hermitian induced transition as a probe, We propose a new procedure of estimating localization in arbitrary-dimensional systems. By examining numerically the two-dimensional no

  8. Anna Okopińska

    The optimized expansion is used to formulate a systematic approximation scheme to the probability distribution of a stochastic system. The first order approximation for the one-dimensional system driven by noise in an anharmonic potential is shown to agree well with the exact solution of the Fokker-Planck equation. Even for a bistable system the whole period

  9. H. K. C. Yee, M. D. Gladders

    We present a brief review of the history of optical searches of galaxy clusters, starting from that of Abell. The traditional application of this survey method suffers from contamination due to projection of galaxies along the line of sight, which becomes increasingly more severe at higher redshift. The new generation of wide-field CCD imagers has provided a

  10. A. D. Kaminker, D. G. Yakovlev, O. Y. Gnedin

    Cooling of neutron stars (NSs) with the cores composed of neutrons, protons, and electrons is simulated assuming $^1$S$_0$ pairing of neutrons in the NS crust, and also $^1$S$_0$ pairing of protons and weak $^3$P$_2$ pairing of neutrons in the NS core, and using realistic density profiles of the superfluid critical temperatures $T_{\rm c}(ρ)$. The theoretica

  11. T. Yaqoob, I. M. George, T. J. Turner

    We present new results from a Chandra HETG observation of NGC 5548 and give a comparison of absorption and emission features found in other Seyfert 1 galaxies using Chandra grating observations. Deep soft X-ray edges are seen in Mkn 509 and NGC 3783, consistent with ASCA data. In NGC 5548 and NGC 4501 the edges are weak but consistent with the low column den

  12. W. van Straten

    A new phase-coherent technique for the calibration of polarimetric data is presented. Similar to the one-dimensional form of convolution, data are multiplied by the response function in the frequency domain. Therefore, the system response may be corrected with arbitrarily high spectral resolution, effectively treating the problem of bandwidth depolarization.

  13. D. C. Choudhury

    The initial cosmological singularity in the framework of the general theory of relativity is resolved by introducing the effect of the uncertainty principle of quantum theory without violating conventional laws of physics. A plausible account of the mechanism of the big bang, analogous to that of a nuclear explosion, is given and the currently accepted Planc

  14. J. Mejia, T. Villela, P. Goldoni, F. Lebrun

    We present the results of the GRANAT/SIGMA hard X-/soft gamma-ray long-term monitoring of the Galactic Center (GC) region concerning the source GRO J1744-28, discovered on 1995 Dec. 2 by CGRO/BATSE. SIGMA observed the region containing the source in 14 opportunities between 1990 and 1997. In two of these observing sessions, corresponding to March 1996 and Ma

  15. A. C. Fabian, R. J. Wilman, C. S. Crawford

    Chandra and XMM-Newton have resolved the 2-8 keV X-ray Background (XRB) into point sources. Many of the fainter sources are obscured active galactic nuclei (AGN) with column densities in the range of 10^22-10^23 pcmsq, some of which have quasar-like luminosities. According to obscuration models, the XRB above 8 keV is dominated by emission from Compton-thick

  16. H. C. Spruit, R. E. Taam

    Observations of Cataclysmic Variables show a number of phenomena that do not fit easily into the standard magnetic braking scenario. These include the large spread in mass transfer rates, the low surface temperatures of many of the companion stars, and evidence for material at low velocities. We propose that these anomalies have a common cause: the presence

  17. T. Yaqoob, U. Padmanabhan, T. Dotani, I. M. George

    Chandra and XMM observations are showing that the Fe-K emission lines in type 1 AGN are composite, in general consisting of a narrow and a broad component. We review the latest Chandra HETG results and compare the line profiles with those measured by ASCA. The narrow Fe-K line components necessitate re-modeling of the line profiles measured previously and re

  18. A. C. Fabian, A. Celotti, K. M. Blundell, N. E. Kassim

    High resolution X-ray and low frequency radio imaging now allow us to examine in detail the interaction and physical properties of the radio source 3C84 and the surrounding thermal gas. The radiative and dynamical properties of the inner X-ray holes, which coincide with the radio lobes, indicate that the ratio of the energy factor k and filling factor f is i

  19. K. Dimopoulos, J. W. F. Valle

    We develop general criteria to construct unified frameworks for inflation and quintessence which employ a unique scalar field to drive both. By using such a minimal theoretical framework we avoid having to fine-tune couplings and mass-scales. In particular the initial conditions for quintessence are already fixed at the end of the inflationary epoch. We prov

  20. O. Bertolami, M. C. Bento, R. Rosenfeld

    We derive bounds on the Higgs boson coupling $g^{\prime}$ to a stable light scalar which is regarded as a collisional dark matter candidate. We study the behaviour of this scalar, that we refer to as phion ($ϕ$), in the early Universe for different ranges of its mass. We find that a phion in the mass range of $100 \mev$ is excluded, while if its mass is abou

  21. P. K. Sahu, G. F. Burgio, M. Baldo

    We make a first calculation of eigenfrequencies of radial pulsations of neutron stars with quark cores in a general relativistic formalism given by Chandrasekhar. The equations of state (EOS) used to estimate such eigenfrequencies have been derived by taking proper care of the hadron-quark phase transition. The hadronic EOS's have been obtained in the fr

  22. Alberto Franceschini, Dario Fadda, Catherine Cesarsky, David Elbaz

    We analyse very deep X-ray and mid-IR surveys in common areas of the Lockman Hole and the HDF North to study the sources of the X-ray background (XRB) and to test the standard obscured accretion paradigm. We detect with ISO a rich population of X-ray luminous sources with red optical colours, including a fraction identified with Extremely Red Objects (R-K >

  23. Dario Fadda, Hector Flores, Guenther Hasinger, Alberto Franceschini

    We provide constraints on the AGN contribution to the mid-IR extragalactic background light from a correlation analysis of deep X-ray and mid-IR observations in two regions centred on the Lockman Hole (LH) and Hubble Deep Field North (HDFN). Among the 76 galaxies detected by XMM in the LH area (200 square arcminutes), 24 show mid-IR emission, but the relativ

  24. B. Vollmer, T. Beckert

    The equilibrium state of a turbulent clumpy gas disk is analytically investigated. The disk consists of distinct self-gravitating clouds. Gravitational cloud-cloud interactions transfer energy over spatial scales and produce a viscosity, which allows mass accretion in the gas disk. Turbulence is assumed to be generated by instabilities involving self-gravita

  25. T. Oshima, K. Mitsuda, R. Fujimoto, N. Iyomoto

    We present the X-ray energy spectrum of the lensed BAL QSO H1413+117 (the Cloverleaf) at z=2.56 observed with the Chandra X-ray observatory. We detected 293 photons in a 40 ks Advanced CCD Imaging Spectrometer (ACIS-S) observation. The X-ray image consists of four lensed image components, thus the photons are from the lensed QSO itself. The overall spectrum

  26. S. Basilakos, I. Georgantopoulos, I. Pérez-Fournon, A. Efstathiou

    We present a cross-correlation between the ELAIS 15$μ$m ISO survey with the {\it ROSAT} (0.1-2 keV) all-sky survey and the pointed observations WGACAT source catalogue. The resulting sample contains 15 objects. Optical spectroscopic identifications exist for 13 objects: 6 broad-line QSOs, 4 narrow line galaxies or type-2 AGN (NLG) and 3 stars. We have used b

  27. Jose Franco, Jongsoo Kim, Emilio J. Alfaro, Seung Soo Hong

    Here we present three-dimensional MHD models for the Parker instability in a thick magnetized disk, including the presence of a spiral arm. The $B$-field is assumed parallel to the arm, and the model results are applied to the optical segment of the Carina-Sagittarius arm. The characteristic features of the undular and interchange modes are clearly apparent

  28. R Dodson, M Howlett, K. Golap, N. Udaya Shankar

    The association of G343.1-2.3 and PSR 1706-44 has been controversial from its first proposal. In this paper we present new evidence from images made by with the Australia Telescope Compact Array (ATCA), MRT and Mt. Pleasant. To cover the full extent of G343.1-2.3 with ATCA mosaicing was required, and we present the polarisation images from this experiment. T

  29. R Dodson, D. R. Lewis, P. M. McCulloch

    Pulsars are rotating neutron stars, sweeping the emission regions from the magnetic poles across our line of sight. Isolated neutron stars lose angular momentum through dipole radiation and (possibly) particle winds, hence they slow down extremely steadily, making them amongst the most reliable timing sources available. However, it is well known that younger

  30. T. Kajino, S. Wanajo, G. J. Mathews

    We study the r-process nucleosynthesis in neutrino-driven winds of gravitational core collapse SNeII. Appropriate physical conditions are found for successful r-process nucleosynthesis, which meet with several features of heavy elements discovered recently in metal-deficient halo stars. We find also several difficulties which are not explained in the present

  31. Maxim Lyutikov

    The dynamics of a relativistic blast wave propagating through magnetized medium is considered taking into account possible inhomogeneities of density and magnetic field and additional energy supply. Under the simplifying assumption of a spherically symmetric explosion in a medium with toroidal magnetic field self-similar solutions for the internal dynamics o

  32. H. Mutschke, Th. Henning, D. Clément, A. C. Andersen

    In this paper we demonstrate that distinguishing between the polytypes of silicon carbide by means of infrared features in small-grain spectra is impossible. Therefore, the infrared spectra of carbon stars, unfortunately, do not provide a means for drawing comparisons between the crystal structures of grains condensed in these environments and found in meteo

  33. Zenji Hiroi, Touru Yamauchi, Takahiro Yamada, Masafumi Hanawa

    Superconducting and structural phase transitions in a pyrochlore oxide Cd2Re2O7 are studied under high pressure by x-ray diffraction and electrical resistivity measurements. A rich P-T phase diagram is obtained, which contains at least two phases with the ideal and slightly distorted pyrochlore structures. It is found that the transition between them is supp

  34. Juan Maldacena, Hirosi Ooguri

    We consider correlation functions for string theory on AdS_3. We analyze their singularities and we provide a physical interpretation for them. We explain which worldsheet correlation functions have a sensible physical interpretation in terms of the boundary theory. We consider the operator product expansion of the four point function and we find that it fac

  35. Frederic Leblond, Robert C. Myers, David C. Page

    Following hep-th/0109127, we show that a certain class of BPS naked singularities (superstars) found in compactifications of M-theory can be interpreted as being composed of giant gravitons. More specifically, we study superstars which are asymptotically AdS_7 x S^4 and AdS_4 x S^7 and show that these field configurations can be interpreted as being sourced

  36. Jorge Alfaro, Gonzalo Palma

    Loop quantum gravity effective theories are reviewed in the context of the observed GZK limit anomaly and related processes. This is accomplished through a kinematical analysis of the modified threshold conditions for the involved decay reactions, arising from the theory. Specially interesting is the possibility of an helicity dependant violation of the limi

  37. Pedro T. P. Viana, Robert C. Nichol, Andrew R. Liddle

    We describe a new approach to constrain the amplitude of the power spectrum of matter perturbations in the Universe, parametrized by sigma_8 as a function of the matter density Omega_0. We compare the galaxy cluster X-ray luminosity function of the REFLEX survey with the theoretical mass function of Jenkins et al. (2001), using the mass-luminosity relationsh

  38. Takamitsu Miyaji, Richard E. Griffiths

    We report the results of fluctuation analysis of the off-source field from the 1 Million second Chandra observation of the Hubble Deep Field-North (HDF-N). The distribution of the counts in cells has been compared with the expectations from the Log N - Log S model to constrain the behavior of the source number density down to a factor of several lower than t

  39. Max Karlovini

    The aim of this paper is to present a governing equation for first order axial metric perturbations of general, not necessarily static, spherically symmetric spacetimes. Under the non-restrictive assumption of axisymmetric perturbations, the governing equation is shown to be a two-dimensional wave equation where the wave function serves as a twist potential

  40. Albert Schwarz

    We consider gauge theories on noncommutative euclidean space . In particular, we discuss the structure of gauge group following standard mathematical definitions and using the ideas of hep-th/0102182.

  41. L. Tresse, S. J. Maddox, O. Le Fevre, J. -G. Cuby

    We describe ISAAC/ESO-VLT observations of the Ha(6563) Balmer line of 33 field galaxies from the Canada-France Redshift Survey (CFRS) with redshifts selected between 0.5 and 1.1. We detect Ha in emission in 30 galaxies and compare the properties of this sample with the low-redshift sample of CFRS galaxies at z~0.2 (Tresse & Maddox 1998). We find that the Ha

  42. K. -I. Imura, K. -V. Pham, P. Lederer, F. Piechon

    We discuss the conductance of quantum wires (QW) in terms of the Tomonaga-Luttinger liquid (TLL) theory. We use explicitly the charge fractionalization scheme which results from the chiral symmetry of the model. We suggest that results of the standard two-terminal (2T) conductance measurement depend on the coupling of TLL with the reservoirs and can be inter

  43. Tommy Ohlsson, Walter Winter

    In neutrino physics, it is now widely believed that neutrino oscillations are influenced by the presence of matter, modifying the energy spectrum produced by a neutrino beam traversing the Earth. Here, we will discuss the reverse problem, i.e. what could be learned about the Earth's interior from a single neutrino baseline energy spectrum, especially abo

  44. M. Carena, J. Ellis, A. Pilaftsis, C. E. M. Wagner

    Extending previous results obtained in the effective-potential approach, we derive analytic expressions for the pole masses of the charged and neutral Higgs bosons in the minimal supersymmetric standard model (MSSM) with explicit CP violation. In such a minimal supersymmetric model, the CP invariance of the Higgs potential is explicitly broken by quantum eff

  45. Volker Runde

    We prove that the following are equivalent for a locally compact group $G$: (i) $G$ is amenable; (ii) $M(G)$ is Connes-amenable; (iii) $M(G)$ has a normal, virtual diagonal.

  46. D. Boyanovsky, S. -Y. Wang, D. -S. Lee, H. -L. Yu

    We present a field-theoretical method to obtain consistently the equations of motion for small amplitude condensate perturbations in a homogeneous Bose-condensed gas directly in real time. It is based on linear response, and combines the Schwinger-Keldysh formulation of nonequilibrium quantum field theory with the Nambu-Gorkov formalism of quasiparticle exci

  47. Christian Blohmann

    In a representation theoretic approach a free q-relativistic wave equation must be such, that the space of solutions is an irreducible representation of the q-Poincare algebra. It is shown how this requirement uniquely determines the q-wave equations. As examples, the q-Dirac equation (including q-gamma matrices which satisfy a q-Clifford algebra), the q-Wey

  48. Ming Li, Xin Chen, Xin Li, Bin Ma

    A new class of distances appropriate for measuring similarity relations between sequences, say one type of similarity per distance, is studied. We propose a new ``normalized information distance'', based on the noncomputable notion of Kolmogorov complexity, and show that it is in this class and it minorizes every computable distance in the class (tha

  49. J. L. Jacobsen, P. Zinn-Justin

    Rephrasing the backbone of two-dimensional percolation as a monochromatic path crossing problem, we investigate the latter by a transfer matrix approach. Conformal invariance links the backbone dimension D_b to the highest eigenvalue of the transfer matrix T, and we obtain the result D_b=1.6431 \pm 0.0006. For a strip of width L, T is roughly of size 2^{3^L}

  50. K. Van Acoleyen, H. Verschelde

    We probe the U(N) Gross-Neveu model with a source-term $J\barΨΨ$. We find an expression for the renormalization scheme and scale invariant source $\hat{J}$, as a function of the generated mass gap. The expansion of this function is organized in such a way that all scheme and scale dependence is reduced to one single parameter d. We get a non-perturbative mas

  51. P. V. Ruuskanen

    Results on initial transverse energy production based on NLO perturbative QCD calculation with final state saturation of produced minijets are used to fix the initial energy density of produced matter. Assuming rapid thermalization, this provides the initial conditions for a hydrodynamic description of the expansion of final matter. Given a prescription of t

  52. Sukanta Bose, L. P. Grishchuk

    We develop a theory in which relic gravitational waves and primordial density perturbations are generated by strong variable gravitational field of the early Universe. The generating mechanism is the superadiabatic (parametric) amplification of the zero-point quantum oscillations. The generated fields have specific statistical properties of squeezed vacuum q

  53. Marek Gierlinski, Chris Done

    Disc accreting neutron stars come in two distinct varieties, atolls and Z sources, named after their differently shaped tracks on a colour-colour diagram as the source luminosity changes. Here we present analysis of three transient atoll sources showing that there is an additional branch in the colour-colour diagram of atoll sources which appears at very low

  54. John Atwell Moody

    This paper gives conditions for a singular foliation to be resolved.

  55. V. M. Khatsymovsky

    The problem of fixing measure in the path integral for the Regge-discretised gravity is considered from the viewpoint of it's "best approximation" to the already known formal continuum general relativity (GR) measure. A rigorous formulation may consist in comparing functional Fourier transforms of the measures, i.e. characteristic or generating f

  56. G. Mao, V. N. Kondratyev, A. Iwamoto, Z. Li

    We study the problem of neutron star composition in the presence of a strong magnetic field. The effects of the anomalous magnetic moments of both nucleons and electrons are investigated in relativistic mean field calculations for a $β$-equilibrium system. Since neutrons are fully spin polarized in a large field, generally speaking, the proton fraction can n

  57. E. G. Drukarev, M. G. Ryskin, V. A. Sadovnikova

    The values of four-quark operators averaged over pions are expressed through those averaged over vacuum. The specific values are obtained in the framework of the factorization assumption. For the condensates of the light quarks of the same flavour \bar qΓq\bar qΓq the scalar condensate is shown to be an order of magnitude larger than the other ones. The cond

  58. Arthur Lue

    If the graviton possesses an arbitrarily small (but nonvanishing) mass, perturbation theory implies that cosmic strings have a nonzero Newtonian potential. Nevertheless in Einstein gravity, where the graviton is strictly massless, the Newtonian potential of a cosmic string vanishes. This discrepancy is an example of the van Dam--Veltman--Zakharov (VDVZ) disc

  59. Keiichi Akama, Takashi Hattori, Kazuo Katsuura

    Assuming naturalness that the quantum corrections to the mass should not exceed the order of the observed mass, we derive and apply model-independent bounds on the anomalous magnetic moments and electric dipole moments of leptons and quarks due to new physics.

  60. Hidetoshi Nishimori, Koji Nemoto

    Determination of the precise location of the multicritical point and phase boundary is a target of active current research in the theory of spin glasses. In this short note we develop a duality argument to predict the location of the multicritical point and the shape of the phase boundary in models of spin glasses on the square lattice.

  61. P. J. Turner, R. Harris, Saeid Kamal, M. E. Hayden

    There has long been a discrepancy between microwave conductivity measurements in high temperature superconductors and the conductivity spectrum expected in the simplest models for impurity scattering in a d-wave superconductor. Here we present a new type of broadband measurement of microwave surface resistance that finally shows some of the spectral features

  62. David Collins

    The translation of Grover's search algorithm from its standard version, designed for implementation on a single quantum system amenable to projective measurements, into one suitable for an ensemble of quantum computers, whose outputs are expectation values of observables, is described in detail. A filtering scheme, which effectively determines expectatio

  63. Jaromir Fiurasek

    We investigate properties of the structural physical approximation (SPA) of the partial transposition map recently introduced by Horodecki and Ekert [quant-ph/0111064]. We focus on the case of two-qubit states and show that in this case the map has the structure of a generalized quantum measurement followed by preparation of a suitable output state. We also

  64. Miroslav Pardy

    The Schroedinger equation with the nonlinear term is derived by the natural generalization of the hydrodynamical model of quantum mechanics. The nonlinear term appears to be logically necessary because it enables explanation of the classical limit of the wave function, the collaps of the wave function and solves the Schroedinger cat paradox.

  65. Gao Xianlong, W. Wonneberger

    A many body theory for a two-component system of spin polarized interacting fermions in a one-dimensional harmonic trap is developed. The model considers two different states of the same fermionic species and treats the dominant interactions between the two using the bosonization method for forward scattering. Asymptotically exact results for the one-particl

  66. J. C. Martinez, E. Polatdemir

    We consider a symmetric double barrier heterostructure enclosing a well and propose a solution for the transmission problem using a generalized WKB approach which accounts for the amplitude suppression and phase shift due to the barriers. This approach allows us to address both off-resonance and resonance cases and, in the latter case, verify the coherent de

  67. Scott Aaronson

    The collision problem is to decide whether a function X:{1,..,n}->{1,..,n} is one-to-one or two-to-one, given that one of these is the case. We show a lower bound of Theta(n^{1/5}) on the number of queries needed by a quantum computer to solve this problem with bounded error probability. The best known upper bound is O(n^{1/3}), but obtaining any lower bound

  68. H. P. Yuen

    Bit commitment involves the submission of evidence from one party to another so that the evidence can be used to confirm a later revealed bit value by the first party, while the second party cannot determine the bit value from the evidence alone. It is widely believed that unconditionally secure quantum bit commitment is impossible due to quantum entanglemen

  69. R. Abbott, P. King

    To meet the strain sensitivity requirements [1], [2] of the Laser Interferometer Gravitational Wave Observatory (LIGO), the laser frequency and amplitude noise must initially be reduced by a factor of 1000 in the pre-stabilized portion of the interferometer [3]. A control system was implemented to provide laser noise suppression, data acquisition interfaces,

  70. J. C. L. Brazier, A. Dinius, P. Semanaz

    By the end of the nineties, the power converter control system (Mugef) of the CERN proton accelerator (SPS) had undergone a complete modernization. This resulted in newly developed hardware for function generation, measurement and I/O in a VME environment, under the LynxOS real-time operating system. This has provided a platform on which extensions can be de

  71. P. Chevtsov, S. Schaffner

    Each accelerator control system has a variety of measurement devices. One of the most common types of instrument interfaces used for their control is a serial (RS-232) bus. It is inexpensive and adequate for relatively simple measurement and control devices such as switchers, amplifiers, voltmeters, and steppermotors. Since the RS-232 specification is very b

  72. D. Mugnai

    The tunnel effect is considered here within the framework of electromagnetic propagation. The classical problem of a plane gap of dielectric, surrounded on both sides by a medium with larger refraction index, is studied in the case in which an electromagnetic plane wave impinges into the gap with an incidence angle larger than the critical angle. In this con

  73. C. B. Das, S. Das Gupta, A. Majumder

    We consider a model where, for a finite disintegrating system, yields of composites can be calculated to arbitrary accuracy. An analytic answer for yields is also known in the thermodynamic limit. In the range of temperature and density considered in this work, the model has a phase transition. This phase transition is first order. The analytic expression fo

  74. C. Barbieri, W. H. Dickhoff

    The Faddeev technique is employed to study the influence of both particle-particle and particle-hole phonons on the one-hole spectral function of O16. Collective excitations are accounted for at a random phase approximation level and subsequently summed to all orders by the Faddeev equations to obtain the nucleon self-energy. An iterative procedure is applie

  75. Christelle roy, STAR Collaboration

    Strangeness study is one of the major goal of the STAR experiment at RHIC. Results presented here have been obtained from analyses restricted to the mid-rapidity region of Au-Au collisions at $\sqrt{s_{NN}}$ = 130 GeV. An onset of the understanding of the quark matter behavior produced at this relativistic energy can be stressed from the investigation of the

  76. M. Bertani

    FINUDA is a hypernuclear physics experiment that will be carried out at DA$Φ$NE, the $e^+e^-$ $ϕ$-factory currently in operation at the INFN Frascati Laboratory. The apparatus, which is assembled in the DA$Φ$NE hall, consists of a magnetic spectrometer with high resolution tracking capabilities. In this paper the status of the experiment is presented, togeth

  77. Robert L. Pego, Jose Raul Quintero

    We describe traveling waves in a basic model for three-dimensional water-wave dynamics in the weakly nonlinear long-wave regime. Small solutions that are periodic in the direction of translation (or orthogonal to it) form an infinite-dimensional family. We characterize these solutions through spatial dynamics, by reducing a linearly ill-posed mixed-type init

  78. Enrico Calzavarini, Federico Toschi, Raffaele Tripiccione

    We present new results from high-resolution high-statistics direct numerical simulations of a tri-dimensional convective cell. We test the fundamental physical picture of the presence of both a Bolgiano-like and a Kolmogorov-like regime. We find that the dimensional predictions for these two distinct regimes (characterized respectively by an active and passi

  79. P. G. Grinevich, S. P. Novikov

    An effective description of the inverse spectral data corresponding to the real periodic and quasiperiodic solutions for the sine-gordon equation is obtained. In particular, the explicit formula for the so-called topological charge of the solutions is found and proved. As it was understood already 20 years ago, it is very hard to extract any formula for this

  80. Cedric Bonnafe

    We construct a new isomorphism between the endomorphism algebra of an induced cuspidal character sheaf and the group algebra of the relative Weyl group involved. We show it differs from Lusztig one by a linear character, and we relate this linear character to some stabilizers. Some consequences on characteristic functions of character sheaves are obtained. I

  81. Peter J. Kahn

    The notion of a pseudocycle is introduced by McDuff and Salamon (J-holomorphic curves and quantum cohomology, University Lecture Series, Vol. 6, AMS (1994)) to provide a framework for defining Gromov-Witten invariants and quantum cohomology. This paper studies the bordism groups of pseudocycles, called pseudohomology groups. These are shown to satisfy the Ei

  82. Jasper V. Stokman

    In the first part of the paper kernels are constructed which meromorphically extend the Macdonald-Koornwinder polynomials in their degrees. In the second part of the paper the kernels associated with rank one root systems are used to define nonsymmetric variants of the spherical Fourier transform on the quantum SU(1,1) group. Related Plancherel and inversion

  83. W. Chen

    The purpose of this study is to apply some new RBF collocation schemes and recently-developed kernel RBFs to various types of partial differential equation systems. By analogy with the Fasshauer's Hermite interpolation, we recently developed the symmetric BKM and boundary particle methods (BPM), where the latter is based on the multiple reciprocity princ

  84. F. E. Burstall, J. -H. Eschenburg, M. J. Ferreira, R. Tribuzy

    We investigate the local geometry of a class of Kähler submanifolds $M \subset \R^n$ which generalize surfaces of constant mean curvature. The role of the mean curvature vector is played by the $(1,1)$-part (i.e. the $dz_id\bar z_j$-components) of the second fundamental form $α$, which we call the pluri-mean curvature. We show that these Kähler submanifolds

  85. F. Loeser

    We study the behaviour of motivic zeta functions of prehomogeneous vector spaces under castling transformations. In particular we deduce how the motivic Milnor fibre and the Hodge spectrum at the origin behave under such transformations.

  86. E. Bierstone, P. D. Milman, W. Pawlucki

    In 1934, Whitney raised the question of how to recognize whether a function f defined on a closed subset X of Euclidean space is the restriction of a function that is continuously differentiable to order p. A necessary and sufficient criterion was given in the case n=1 by Whitney, using limits of finite differences, and in the case p=1 by Glaeser (1958), usi

  87. Yevgenia Kashina, Geoffrey Mason, Susan Montgomery

    In this paper we show that for an important class of non-trivial Hopf algebras, the Schur indicator is a computable invariant. The Hopf algebras we consider are all abelian extensions; as a special case, they include the Drinfeld double of a group algebra. In addition to finding a general formula for the indicator, we also study when it is always positive. I

  88. L. Kadison, K. Szlachanyi

    We introduce a general notion of depth two for ring homomorphism N --> M, and derive Morita equivalence of the step one and three centralizers, R = C_M(N) and C = End_{N-M}(M ø_N M), via dual bimodules and step two centralizers A = End_NM_N and B = (M ø_N M)^N, in a Jones tower above N --> M. Lu's bialgebroids End_k A' and A' ø_k {A'}^op over

  89. Bogdan Ion

    We establish a connection between a specialization of the nonsymmetric Macdonald polynomials and the Demazure characters of the corresponding affine Kac-Moody algebra. This allows us to obtain a representation-theoretical interpretation of the coefficients of the expansion of the specialized symmetric Macdonald polynomials in the basis formed by the irreduci

  90. Kiran S. Kedlaya

    We describe an algorithm for counting points on an arbitrary hyperelliptic curve over a finite field of odd characteristic, using Monsky-Washnitzer cohomology to compute a p-adic approximation to the characteristic polynomial of Frobenius. For fixed p, the asymptotic running time for a curve of genus g over the field of p^n elements is O(g^{4+ε} n^{3+ε}).

  91. Roberto Emparan, Michael Gutperle

    In this note we study aspects of the interplay between fluxbranes and p-branes. We describe how a fluxbrane can be physically realized as a limit of a brane-antibrane configuration, in a manner similar to the way a uniform electric field appears in between the plates of a capacitor. We also study the evolution of a fluxbrane after nucleation of p-branes. We

  92. M. S. Goes-Negrao, J. A. Helayel-Neto, and M. R. Negrao

    Following a previous work on Abelian (2,0)-gauge theories, one reassesses here the task of coupling (2,0) relaxed Yang-Mills superpotentials to a (2,0)- nonlinear $σ$-model, by gauging the isotropy or the isometry group of the latter. One pays special attention to the extra ``chiral-like'' component-field gauge potential that comes out from the relax

  93. Thomas L Curtright, Alexios P Polychronakos, Cosmas K Zachos

    Systems built out of N-body interactions, beyond 2-body interactions, are formulated on the plane, and investigated classically and quantum mechanically (in phase space). Their Wigner Functions--the density matrices in phase-space quantization--are given and analyzed.

  94. L. Clavelli, P. Coulter, T. Gajdosik

    We investigate the polarization properties of vector quarkonia in lepton anti-lepton annihilation with special attention to effects due to intermediate Z bosons.

  95. Alexander Khodjamirian, Daniel Wyler

    We clarify the origin and cancellation of contact terms in the weak annihilation amplitudes contributing to $B\to V γ$. It is demonstrated that the photon emission from the final-state quarks vanishes in the chiral limit of massless quarks. The contact terms in the QCD light-cone sum rule evaluation of the weak annihilation amplitudes are also discussed.

  96. T. Barnes

    In this HADRON2001 contribution we summarize the status of our quark-model calculations of hadron-hadron scattering amplitudes in annihilation-free channels. The predictions are in reasonably good agreement with experimentally known S-wave meson-meson and meson-baryon phase shifts, and there are very recent indications that S-wave pi-omega scattering (extrac

  97. Karine Leroux, David London

    Leptophobic Z' gauge bosons can appear in models with an E_6 gauge symmetry. We show that flavour-changing neutral currents can be generated in some of these models due to the mixing of the ordinary d_R, s_R and b_R quark fields with the exotic h_R. Because the Z' does not couple to charged leptons, the constraints on the flavour-changing couplings U

  98. A. H. Mueller

    The idea of partons and the utility of using light-cone gauge in QCD are introduced. Saturation of quark and gluon distributions are discussed using simple models and in a more general context. The Golec-Biernat W\usthoff model and some simple phenomenology are described. A simple, but realistic, equation for unitary, the Kovchegov equation, is discussed, an

  99. Andreas Hocker

    The recent precise measurement of the muon magnetic anomaly (g-2)_{mu} at BNL opens a window into possible new physics, provided the contribution from hadronic vacuum polarization is well understood. This talk summarizes the development in the evaluation of the leading order hadronic contributions. Significant improvement has been achieved in a series of ana

  100. P. Taxil, E. Tugcu, J. -M. Virey

    We explore the sensitivity and the physics interest of the measurement of parity-violating spin asymmetries in one-jet production in the presence of a new leptophobic neutral gauge boson Z', within polarized hadronic collisions at the BNL RHIC. We focus on polarized neutron collisions which could be achieved in a realistic upgrade of the RHIC-Spin progra