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August 2002 arXiv papers — page 20

Showing 1,901–2,000 of 2,694 papers

  1. Xin-Nian Wang

    Medium modification of jet fragmentation functions and parton energy loss in cold and hot matter are reviewed. The predicted nuclear modification of the jet fragmentation function agrees well with the recent HERMES data with a resultant energy loss dE/dx approximately 0.5 GeV/fm. From the the recent PHENIX data of high p_T pi_0 spectra in central Au+Au colli

  2. J. Bartelski, S. Tatur

    In order to determine polarized parton densities in nucleon we have made fits using all experimental data on spin asymmetries measured in the deep inelastic scattering on different nucleon targets. We have used in our analysis next to leading order QCD corrections in bar{MS} renormalization scheme. The functional forms of polarized densities are based on the

  3. P. Aliani, V. Antonelli, M. Picariello, E. Torrente-Lujan

    We investigate the possibility of detecting solar antineutrinos with the KamLAND experiment. These antineutrinos are predicted by spin-flavor oscillations at a significant rate even if this mechanism is not the leading solution to the SNP. The recent evidence from SNO shows that a) the neutrino oscillates, only around 34% of the initial solar neutrinos arriv

  4. M. Ciuchini, L. Silvestrini

    In the presence of large New Physics contributions to loop-induced b->s transitions, sizable direct CP violation in B-> phi K decays is expected on general grounds. We compute explicitly CP-violating effects using QCD factorization and find that, even in the restricted case in which New Physics has the same penguin structure as the Standard Model, the rate a

  5. H. Kröger, X. Q. Luo, K. J. M. Moriarty

    We present a new way to compute thermodynamical observables on the lattice. We compute excited states and thermodynamical functions in the scalar model via the Monte Carlo Hamiltonian technique. We find agreement with standard Lagrangian lattice calculations, but observe lesser fluctuations in the results from the MC Hamiltonian.

  6. V. A. Batarin, J. Butler, A. A. Derevschikov, Yu. V. Formin

    A beam line for electrons with energies in the range of 1 to 45 GeV, low contamination of hadrons and muons and high intensity up to 10^6 per accelerator spill at 27 GeV was setup at U70 accelerator in Protvino, Russia. A beam tagging system based on drift chambers with 160 micron resolution was able to measure relative electron beam momentum precisely. The

  7. L. Afanasyev, V. Karpukhin

    A drift chamber readout system of the DIRAC experiment at CERN is presented. The system is intended to read out the signals from planar chambers operating in a high current mode. The sense wire signals are digitized in the 16-channel time-to-digital converter boards which are plugged in the signal plane connectors. This design results in a reduced number of

  8. A. N. Aliev, N. Ozdemir

    We study the effects of an external magnetic field, which is assumed to be uniform at infinity, on the marginally stable circular motion of charged particles in the equatorial plane of a rotating black hole. We show that the magnetic field has its greatest effect in enlarging the region of stability towards the event horizon of the black hole. Using the Hami

  9. V. Dzhunushaliev

    We calculate dimensional reduction of gravitational flux tube solutions in the scheme of Kaluza-Klein theory. The fifth dimension is compacified to a region of Planck size. Assuming the width of the tube to be also Planck size we obtain string-like object with physical fields originated from an initial 5D metric. The dynamics of these fields is inner one.

  10. Akihiro Ishibashi, Takahiro Tanaka

    No, it cannot in the following sense if a self-gravitating vacuum brane is concerned. Once we write down the full set of linear perturbation equations of the system containing a self-gravitating brane, we will see that such a brane does not have its own dynamical degrees of freedom independent of those of gravitational waves which propagate in the surroundin

  11. P. Levy, F. Parisi, J. Sacanell, L. Granja

    We have studied magnetic and transport properties on different manganese oxide based compounds exhibiting phase separation: polycrystalline La5/8-yPryCa3/8MnO3 (y=0.3) and La1/2Ca1/2Mn1-zFezO3 (z = 0.05), and single crystals of La5/8-yPryCa3/8MnO3 (y=0.35). Time dependent effects indicate that the fractions of the coexisting phases are dynamically changing i

  12. S. Boettcher

    The average ground state energy and entropy for +/- J spin glasses on Bethe lattices of connectivities k+1=3...,26 at T=0 are approximated numerically. To obtain sufficient accuracy for large system sizes (up to n=2048), the Extremal Optimization heuristic is employed which provides high-quality results not only for the ground state energies per spin e_{k+1}

  13. Takeya Unuma, Masahiro Yoshita, Takeshi Noda, Hiroyuki Sakaki

    We calculate the intersubband absorption linewidth in quantum wells (QWs) due to scattering by interface roughness, LO phonons, LA phonons, alloy disorder, and ionized impurities, and compare it with the transport energy broadening that corresponds to the transport relaxation time related to electron mobility. Numerical calculations for GaAs QWs clarify the

  14. B. J. LeRoy, A. C. Bleszynski, M. A. Topinka, R. M. Westervelt

    Images of electron flow through a two-dimensional electron gas from a quantum point contact (QPC) can be obtained at liquid He temperatures using scanning probe microscopy (SPM). A negatively charged SPM tip depletes the electron gas immediately below it and decreases the conductance by backscattering electrons. Images of electron flow are obtained by record

  15. S. Wakimoto, C. Stock, Z. -G. Ye, W. Chen

    We present a quantitative analysis of the phonon lineshapes obtained by neutron inelastic scattering methods in the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 (PMN). Differences in the shapes and apparent positions of the transverse acoustic (TA) and transverse optic (TO) phonon peaks measured in the (300) and (200) Brillouin zones at 690 K are well described by

  16. S. Nishimoto, E. Jeckelmann, D. J. Scalapino

    Here we report results of a density-matrix-renormalization-group (DMRG) calculation of the charge, spin, and pairing properties of a two-leg CuO Hubbard ladder. The outer oxygen atoms as well as the rung and leg oxygen atoms are included along with near-neighbor and oxygen-hopping matrix elements. This system allows us to study the effects of hole and electr

  17. V. A. Ivanov, P. M. Krstajic, F. M. Peeters, V. Fleurov

    A microscopic Hamiltonian for interacting manganese impurities in diluted magnetic semiconductors (DMS) is derived. It is shown that in p -type III-V DMS the indirect exchange between Mn impurities has similarities with the Zener mechanism in transition metal oxides. Here the mobile holes and localized states near the top of the valence band play the role of

  18. Ö. Legeza, J. Röder, B. A. Hess

    We have studied the ionic--neutral curve crossing between the two lowest ^1 Sigma^+ states of LiF in order to demonstrate the efficiency of the quantum chemistry version of the density matrix renormalization group method (QC-DMRG). We show that QC-DMRG is capable to calculate the ground and several low-lying excited state energies within the error margin set

  19. Luca Salasnich

    We investigate the quantum tunneling of a Bose-Einstein condensate confined in a optical trap. We show that periodic pulses of coherent matter are emitted from the trap by using an oscillating energy barrier. Moreover, the emitted fraction of condensed atoms strongly increases if the period of oscillation of the height of the energy barrier is in parametric

  20. A. Alan Middleton

    The four dimensional Gaussian random field Ising magnet is investigated numerically at zero temperature, using samples up to size $64^4$, to test scaling theories and to investigate the nature of domain walls and the thermodynamic limit. As the magnetization exponent $β$ is more easily distinguishable from zero in four dimensions than in three dimensions, th

  21. Shin-ichi Sasa, Hal Tasaki

    Following the proposal of steady state thermodynamics (SST) by Oono and Paniconi, we develop a phenomenological theory for steady nonequilibrium states in systems with heat conduction. We find that there is essentially a unique consistent thermodynamics, and make concrete predictions, i.e, the existence of a new osmotic pressure and a shift in the coexistenc

  22. Brian E. Wood, Seth Redfield, Jeffrey L. Linsky, M. S. Sahu

    We use ultraviolet spectra of Capella from the Hubble Space Telescope (HST) and Far Ultraviolet Spectroscopic Explorer (FUSE) satellites to study interstellar absorption lines from the Local Interstellar Cloud (LIC). Measurements of these lines are used to empirically determine the ionization states of carbon, nitrogen, and silicon in the LIC, for comparison

  23. Brian E. Wood, Margarita Karovska, John C. Raymond

    We analyze Ly-alpha fluoresced H2 lines observed in the UV spectrum of Mira B. We identify 13 different sequences fluoresced by 13 different H2 transitions within the Ly-alpha line. The observed H2 line ratios within these sequences imply significant line opacity, so we use a Monte Carlo radiative transfer code to model the line ratios, correcting for opacit

  24. Lev Titarchuk, Kent Wood

    We interpret the correlation over five orders of magnitude between high frequency and low frequency in a quasi-periodic oscillations (QPO) found by Psaltis, Belloni & van der Klis (1999) for black hole (BH), neutron star (NS) systems and then extended by Mauche (2002) to white dwarf (WD) binaries. We argue that the observed correlation is a natural consequen

  25. P. C. Boeshaar, V. E. Margoniner, the Deep Lens Survey Team

    The initial results of the Deep Lens Survey (http://dls.bell-labs.com) to identify possible brown dwarfs and extremely metal poor red halo subdwarfs near the hydrogen burning limit are presented. Individual deep CCD high galactic latitude survey fields appear to offer a low probability of discovering field BD's, but taken collectively offer an opportunit

  26. M. Markevitch, A. Vikhlinin, W. R. Forman

    Chandra has significantly advanced our knowledge of the processes in the intracluster gas. The discovery of remarkably regular ``cold fronts'', or contact discontinuities, in merging clusters showed that gas dynamic instabilities at the boundaries between the moving gases are often suppressed, most likely by specially structured magnetic fields. Cold

  27. A. Omar, K. S. Dwarakanath, M. Rupen, K. R. Anantharamaiah

    We present Giant Meterwave Radio Telescope (GMRT) observations of the HI 21 cm line and Very Large Array (VLA) observations of the OH 18 cm line from the Seyfert 2 galaxy Mrk 1. HI emission is detected from both Mrk 1 and its companion NGC 451. The HI emission morphology and the velocity field of Mrk 1 are disturbed. We speculate that the nuclear activities

  28. S. H. Lubow, G. I. Ogilvie, J. E. Pringle

    We consider the evolution of a warped disc around a Kerr black hole, under conditions such that the warp propagates in a wavelike manner. This occurs when the dimensionless effective viscosity, alpha, that damps the warp is less than the characteristic angular semi-thickness, H/R, of the disc. We adopt linearized equations that are valid for warps of suffici

  29. John A. Tomsick, William A. Heindl, Deepto Chakrabarty, Philip Kaaret

    We used optical spectroscopy of the neutron star X-ray transient XTE J2123-058 to measure the rotational broadening of the binary companion's stellar absorption lines and determined that the companion's projected rotational velocity is vsini = 121 (+21)(-29) km/s. This value is considerably larger than the measurements of vsini obtained previously fo

  30. M. J. Hardcastle, M. Birkinshaw, R. A. Cameron, D. E. Harris

    We have made deep Chandra observations of three powerful FRII radio sources: two quasars (3C263 and 3C351) and one radio galaxy (3C330). X-ray emission from hotspots and lobes, as well as from the active nucleus, is detected in each source. We model the hotspots' synchrotron spectra using VLA, BIMA and HST data. In 3C263 and 3C330, the hotspots' X-ra

  31. William Herbst, Catrina M. Hamilton, Frederick J. Vrba, Mansur A. Ibrahimov

    Results of an international campaign to photometrically monitor the unique pre-main sequence eclipsing object KH 15D are reported. An updated ephemeris for the eclipse is derived that incorporates a slightly revised period of 48.36 d. There is some evidence that the orbital period is actually twice that value, with two eclipses occurring per cycle. The extra

  32. J. Sanz-Forcada, G. Micela

    All the Extreme Ultraviolet Explorer (EUVE) observations of AD Leo, totalling 1.1 Ms of exposure time, have been employed to analyze the corona of this single M dwarf. The light curves show a well defined quiescent stage, and a distribution of amplitude of variability following a power law with a ~-2.4 index. The flaring behavior exhibits much similarity wit

  33. Nathan Roche, James Lowenthal, David Koo

    Using the HST WFPC2 we perform deep I-band imaging of 9 radio-selected (limit 14 microJanskys at 8.5 GHz) faint galaxies from Roche, Lowenthal and Koo (2002). Two are also observed in V. Six of the galaxies have known redshifs of 0.4<z<1.0. Radial intensity profiles indicate that 7 are disk galaxies and 2 are bulge-dominated. Four of the six with redshifts h

  34. Kazutaka Oka, Takizo Nagae, Takuya Matsuda, Hidekazu Fujiwara

    We simulate numerically the surface flow of a gas-supplying companion star in a semi-detached binary system. Calculations are carried out for a region including only the mass-losing star, thus not the mass accreting star. The equation of state is that of an ideal gas characterized by a specific heat ratio gamma, and the case with gamma=5/3 is mainly studied.

  35. K. Werner, J. L. Deetjen, S. Dreizler, T. Nagel

    We describe our NLTE codes which allow the computation of synthetic spectra of hot stars and accretion disks. They can be combined to compute ionizing fluxes from the hot component in symbiotic stars.

  36. W. H. T. Vlemmings, H. J. van Langevelde, P. J. Diamond

    The 22 GHz H_2O masers in the circumstellar envelope of the Mira variable star U Her have been observed with MERLIN using a phase referencing technique to determine accurate astrometric positions. The positions were compared with the optical positions obtained with the Hipparcos satellite to an accuracy of 18 mas. The absolute radio position of the brightest

  37. W. H. T. Vlemmings, P. J. Diamond, H. J. van Langevelde

    We present circular polarization measurements of circumstellar H_2O masers. The circular polarization detected in the (6_{16}-5_{23}) rotational transition of the H_{2}O maser can be attributed to Zeeman splitting in the intermediate temperature and density regime. The magnetic fields are derived using a general, LTE Zeeman analysis as well as a full radiati

  38. T. P. Roberts, R. S. Warwick, M. J. Ward, S. S. Murray

    (Abridged) We report the results of a 20 ks Chandra ACIS-S observation of the interacting galaxy pair NGC 4485/4490. A total of 29 discrete X-ray sources are found coincident with NGC 4490, but only one is found within NGC 4485. The sources range in observed X-ray luminosity from ~ 2 x 10^37 to ~ 4 x 10^39 erg/s. Extensive diffuse X-ray emission is detected

  39. Kui-Yun Huang, Ing-Guey Jiang

    It was proposed by Blitz et al. (1999) that High Velocity Clouds (HVCs) are remnants of Local Group formation and the average distance of HVCs is 1 Mpc, which is the result of a simple dynamical calculation leading to match the observed HVCs distributions. However, in this paper, we clearly show that fitting the observed HVCs distributions by a dynamical cal

  40. T. Yamamoto, M. Teshima, M. Chikawa, N. Hayashida

    We have developed an atmospheric monitoring system for the Telescope Array experiment at Akeno Observatory. It consists of a Nd:YAG laser with an alt-azimuth shooting system and a small light receiver. This system is installed inside an air conditioned weather-proof dome. All parts, including the dome, laser, shooter, receiver, and optical devices are fully

  41. Charlotte Vastel, Edward Polehampton, Jean-Paul Baluteau, Bruce Swinyard

    High spectral resolution ISO-LWS observations of the [OI] 63.2 and 145.5 microns and [CII] 157.7 microns fine structure lines are presented for the center of the Sagittarius B2 complex (SgrB2). Both the [OI] 63.2 microns and the [CII] 157.7 microns lines are detected in absorption. Using observations of the CO isotopes and of the HI lines, absorption compone

  42. Umin Lee, Shijun Yoshida

    This paper has been withdrawn by the authors, due to inappropriate discussions in Discussions.

  43. S. De Leo, C. C. Nishi, P. Rotelli

    We give a detailed analysis of the oscillation formula within the context of the wave packet formalism. Particular attention is made to insure flavor eigenstate creation in the physical cases (Delta p not equal 0). This requirement imposes non instantaneous particle creation in all frames. It is shown that the standard formula is not only exact when the mass

  44. P. Danielewicz, R. Lacey, W. G. Lynch

    Nuclear collisions can compress nuclear matter to densities achieved within neutron stars and within core-collapse supernovae. These dense states of matter exist momentarily before expanding. We analyzed the flow of matter to extract pressures in excess of 10^34 pascals, the highest recorded under laboratory-controlled conditions. Using these analyses, we ru

  45. Antonio H. Castro Neto, Marcello B. Silva Neto

    We study via renormalization group (RG) and large N methods the problem of continuum SU(N) quantum Heisenberg ferromagnets (QHF) coupled to gapless electrons. We establish the phase diagram of the dissipative problem and investigate the changes in the Curie temperature, magnetization, and magnetic correlation length due to dissipation and both thermal and qu

  46. Masashi Hamanaka, Hiroshige Kajiura

    We discuss gauge fields on tori in diverse dimensions, mainly in two and four dimensions. We construct various explicit gauge fields which have some topological charges and find the Dirac zero modes in the background of the gauge fields. By using the zero mode, we give new gauge fields on the dual torus, which is a gauge theoretical description of T-duality

  47. Walter D. Goldberger, Ira Z. Rothstein

    This work is an extension of our previous work, hep-th/0204160, which showed how to systematically calculate the high energy evolution of gauge couplings in compact AdS_5 backgrounds. We first directly compute the one-loop effects of massive charged scalar fields on the low energy couplings of a gauge theory propagating in the AdS background. It is found tha

  48. Leopoldo A. Pando Zayas, Diana Vaman

    We calculate the thermal partition function in the canonical ensemble for type IIB superstrings in the plane wave background with constant null R-R 5-form. The Hagedorn temperature is found to be higher than the corresponding value for strings in flat space. In the limit corresponding to the weakly coupled field theory we find that the Hagedorn temperature i

  49. J. K. Mizukoshi, Xerxes Tata, Yili Wang

    If tan(beta) is large, down-type quark mass matrices and Yukawa couplings cannot be simultaneously diagonalized, and flavour violating couplings of the neutral Higgs bosons are induced at the 1-loop level. These couplings lead to Higgs-mediated contributions to the decays B_s -> mu+ mu- and B_d -> tau+ tau-, at a level that might be of interest for the curre

  50. Ranty R. Islam, James E. Taylor, Joseph Silk

    We investigate the possibility that present-day galactic haloes contain a population of massive black holes (MBHs) that form by hierarchical merging of the black hole remnants of the first stars. Some of the MBHs may be large enough or close enough to the centre of the galactic host that they merge within a Hubble time. We estimate to what extent this proces

  51. E. Abdalla, K. H. C. Castello-Branco, A. Lima-Santos

    We analyse the spectrum of perturbations of the de Sitter space on the one hand, while on the other hand we compute the location of the poles in the Conformal Field Theory (CFT) propagator at the border. The coincidence is striking, supporting a dS/CFT correspondence. We show that the spectrum of thermal excitations of the CFT at the past boundary $I^{-}$ to

  52. C. Menotti, P. Pedri, S. Stringari

    We study the expansion of a dilute ultracold sample of fermions initially trapped in a anisotropic harmonic trap. The expansion of the cloud provides valuable information about the state of the system and the role of interactions. In particular the time evolution of the deformation of the expanding cloud behaves quite differently depending on whether the sys

  53. Roya Zandi, Joseph Rudnick, Ramin Golestanian

    We report on a study of the shape of a stiff, charged rod that is subjected to equal and opposite force couples at its two ends. Unlike a neutral elastic rod, which forms a constant curvature configuration under such influences, the charged rod tends to flatten in the interior and accumulate the curvature in the end points, to maximally reduce the electrosta

  54. M. N. Chernodub, E. -M. Ilgenfritz, A. Schiller

    On the lattice we study the gauge boson propagator of three dimensional compact QED in Landau gauge at zero and non-zero temperature. The non-perturbative effects are taken into account by the generation of a mass, by an anomalous dimension and by the photon wave function renormalization. All these effects can be attributed to the monopoles: they are absent

  55. Benoit Vanderheyden, A. D. Jackson

    We examine random matrix models of QCD which are capable of supporting both chiral and diquark condensation. A numerical study of the spectral densities near zero virtuality shows that the introduction of color in the interactions does not alter the one-body results imposed by chiral symmetry. A model with three colors has the spectral density predicted for

  56. A. J. Macfarlane, Hendryk Pfeiffer

    The uniformity, for the family of exceptional Lie algebras g, of the decompositions of the powers of their adjoint representations is well-known now for powers up to the fourth. The paper describes an extension of this uniformity for the totally antisymmetrised n-th powers up to n=9, identifying (see Tables 3 and 6) families of representations with integer e

  57. K. Held, E. Eisenberg, B. L. Altshuler

    To lowest order in the coupling strength, the spin-orbit coupling in quantum dots results in a spin-dependent Aharonov-Bohm flux. This flux decouples the spin-up and -down random matrix theory ensembles of the quantum dot. We employ this ensemble and find significant changes in the distribution of the Coulomb blockade peak height, in particular a decrease of

  58. Danko Georgiev

    While looking for evidence of quantum coherent states within the brain, many quantum mind advocates proposed experiments based on the assumption that the coherent state of a photon entering the visual system could somehow be preserved through the neural processing, or in other words they suppose that photons collapse not in the retina, but in the brain corte

  59. Xuelei Wang, Yueling Yang, Bingzhong Li, Lingde Wan

    In the framework of topcolor-assisted technicolor(TC2) model, we study a neutral toppion production process $e^{-}γ\to e^{-}Π^{0}_{t}$ in this paper. Our results show that the production cross section of $e^{-}γ\to e^{-}Π^{0}_{t}$ can reach the level of several tens fb, and over $10^{3}$ neutral toppion events can be produced in the planned $e^+e^-$ linear c

  60. Yuxing Wang, Frederic Bouquet, Ilya Sheikin, Pierre Toulemonde

    We studied the effect of disorder on the superconducting properties of polycrystalline MgB_2 by specific-heat measurements. In the pristine state, these measurements give a bulk confirmation of the presence of two superconducting gaps with 2 Delta 0 / k_B T_c = 1.3 and 3.9 with nearly equal weights. The scattering introduced by irradiation suppresses T_c and

  61. Yasunari Kurita, Masa-aki Sakagami

    We investigate a method to evaluate quasi-normal modes of D3-brane black holes by wave interpretation of fields on D3-brane based on the Feynman&#39;s space-time approach. We perturbatively solve the wave equation which describes propagation of a dilaton wave in a bulk space and its interaction with the D3-brane. The obtained condition for the quasi-normal m

  62. J. F. R. Archilla, J. Cuevas, B. Sánchez Rey, A. Alvarez

    Whereas there exists a mathematical proof for one--site breathers stability, and an unpublished one for two--sites breathers, the methods for determining the stability properties of multibreathers rely in numerical computation of the Floquet multipliers or in the weak nonlinearity approximation leading to discrete non--linear Schrödinger equations. Here we p

  63. L. T. Baby, C. Bordeanu, G. Goldring, M. Hass

    The 7Be(p,gamma)8B reaction plays a central role in the evaluation of solar neutrino fluxes. We report on a new precision measurement of the cross section of this reaction, following our previous experiment with an implanted 7Be target, a raster scanned beam and the elimination of the backscattering loss. The new measurement incorporates a more abundant 7Be

  64. S. Mignemi

    We investigate the gauging of a two-dimensional deformation of the Poincare algebra, which accounts for the existence of an invariant energy scale. The model describes 2D dilaton gravity with torsion. We obtain explicit solutions of the field equations and discuss their physical properties.

  65. Paolo Lisca, Andras I Stipsicz

    We prove that an infinite family of virtually overtwisted tight contact structures discovered by Honda on certain circle bundles over surfaces admit no symplectic semi-fillings. The argument uses results of Mrowka, Ozsvath and Yu on the translation-invariant solutions to the Seiberg-Witten equations on cylinders and the non-triviality of the Kronheimer-Mrowk

  66. Stephan Narison

    We summarize the different features of the scalar mesons from QCD spectral sum rule analyses of the two- and three-point functions. The results do not favour the u-bar u + d-bar d interpretation of the broad and low mass sigma (0.6), and the u-bar s resonance nature of the eventually observed kappa(0.9) meson. We also discuss some OZI-violating and classic s

  67. G. A. Tammann, B. Reindl

    The local (v<1200kms) and the cosmic expansion field out to 30000kms-1 are characterized by Ho=58. While the random error is small (+-2), it may still be affected by systematic errors as large as 10%. The local expansion is outlined by Cepheids and by Cepheid-calibrated TF distances of a complete sample of field galaxies and by nearby groups and clusters; th

  68. Yosef Nir

    Recent measurements of CP violating asymmetries have led to a significant progress in our understanding of CP violation. The implications of the experimental results for the Kobayashi-Maskawa mechanism and for new physics are explained.

  69. Keith Slevin, Peter Markoš, Tomi Ohtsuki

    The single parameter scaling hypothesis is the foundation of our understanding of the Anderson transition. However, the conductance of a disordered system is a fluctuating quantity which does not obey a one parameter scaling law. It is essential to investigate the scaling of the full conductance distribution to establish the scaling hypothesis. We present a

  70. Wen-ge Wang, Baowen Li

    We study the crossover of the quantum Loschmidt echo (or fidelity) from the golden rule regime to the perturbation-independent exponential decay regime by using the kicked top model. It is shown that the deviation of the perturbation-independent decay of the averaged fidelity from the Lyapunov decay results from quantum fluctuations in individual fidelity, w

  71. Z. Y. Zeng, Baowen Li, F. Claro

    A unified theory for the current through a nanoscale region of interacting electrons connected to two leads which can be either ferromagnet or superconductor is presented, yielding Meir-Wingreen-type formulas when applied to specific circumstances. In such a formulation, the requirement of gauge invariance for the current is satisfied automatically. Moreover

  72. Bohdan Grzadkowski, Zenro Hioki

    Angular distribution of a secondary particle from top-quark decays is studied in a simple and general manner, paying careful attention to how relevant the top-quark production mechanism is. The conditions that lead to the distribution free from any possible anomalous top-quark decay interactions are specified. It is discussed how important the approximations

  73. J. E. Palomar, E. Oset

    Starting from effective Lagrangians which combine a gauge formulation of Vector Meson Dominance with Chiral Lagrangians, the coupling of the phi to the nucleon, which is zero at tree level due to the OZI rule, is calculated perturbatively considering loop contributions to the electric and magnetic form factors. We obtain reasonably smaller values for both fo

  74. Matthew Pelton, Charles Santori, Jelena Vuckovic, Bingyang Zhang

    We have demonstrated efficient production of triggered single photons by coupling a single semiconductor quantum dot to a three-dimensionally confined optical mode in a micropost microcavity. The efficiency of emitting single photons into a single-mode travelling wave is approximately 38%, which is nearly two orders of magnitude higher than for a quantum dot

  75. M. F. Andersen, A. Kaplan, N. Davidson

    We investigate the dephasing of ultra cold ^{85}Rb atoms trapped in an optical dipole trap and prepared in a coherent superposition of their two hyperfine ground states by interaction with a microwave pulse. We demonstrate that the dephasing, measured as the Ramsey fringe contrast, can be reversed by stimulating a coherence echo with a pi-pulse between the t

  76. L. -M. Duan, A. Kuzmich, H. J. Kimble

    We propose a method to implement cavity QED and quantum information processing in high-Q cavities with a single trapped but non-localized atom. The system is beyond the Lamb-Dick limit due to the atomic thermal motion. Our method is based on adiabatic passages, which make the relevant dynamics insensitive to the randomness of the atom position with an approp

  77. Mark M. Tracy, A. J. Scott

    We show that the class of quantum baker&#39;s maps defined by Schack and Caves have the proper classical limit provided the number of momentum bits approaches infinity. This is done by deriving a semi-classical approximation to the coherent-state propagator.

  78. F. Spineanu, M. Vlad

    The states of asymptotic relaxation of 2-dimensional fluids and plasma present a high degree of regularity and obey to the sinh-Poisson equation. We find that embedding the classical fluid description into a field-theoretical framework, the same equation appears as a manifestation of the self-duality.

  79. F. Spineanu, M. Vlad

    We propose a new perspective on the intermittency in weakly dissipative systems. It is focused on the elementary (burst-like) event separating states with different properties. This event is seen as a real-space-time manifestation of an instanton connecting in an extended space-time states with distinct topology of the idealized version of the system.

  80. R. Preuss, M. Maraschek, H. Zohm, V. Dose

    We examine a first order differential equation with respect to time coming up in the description of magnetic islands in magnetically confined plasmas. The free parameters of this equation are obtained by employing Bayesian probability theory. Additionally a typical Bayesian change point is solved in the process of obtaining the data.

  81. Amit Halder

    A monochromatic linear source of light is rotated with certain angular frequency and when such light is analysed after reflection then a change of frequency or wavelength may be observed depending on the location of the observer. This change of frequency or wavelength is different from the classical Doppler effect [1] or relativistic Doppler effect [2]. The

  82. E. Altewischer, M. P. van Exter, J. P. Woerdman

    We present angle- and polarization-resolved measurements of the optical transmission of a subwavelength hole array. These results give a (far-field) visualization of the corresponding (near-field) propagation of the excited surface plasmons and allow for a simple analysis of their polarization properties.

  83. Youngsuk Lee, Leslie M. Smith

    Floquet theory is used to describe the unstable spectrum at large scales of the beta-plane equation linearized about Rossby waves. Base flows consisting of one to three Rossby wave are considered analytically using continued fractions and the method of multiple scales, while base flow with more than three Rossby waves are studied numerically. It is demonstra

  84. A. Sibirtsev, S. Krewald, K. Tsushima

    Photoproduction of omega-meson is analyzed within meson exchange model and Regge model and compared to rho-meson photoproduction. An interplay between two models and uncertainties in data reproduction are discussed.

  85. N. Borghini, P. M. Dinh, J. -Y. Ollitrault

    We present a new method for analysing directed flow, based on a three-particle azimuthal correlation. It is less biased by nonflow correlations than two-particle methods, and requires less statistics than four-particle methods. It is illustrated on NA49 data.

  86. H. C. Rosu

    The quantum oscillator thermodynamic actions are the conjugate intensive parameters for the frequency in any frequency changing process. These oscillator actions fulfill simple Riccati equations. Interesting Darboux transformations of the fundamental Planck and pure vacuum actions are discussed here in some detail. It is shown that the one-parameter &#34;Dar

  87. Jeffrey L. Boersema

    We define united K-theory for real C*-algebras, generalizing Bousfield&#39;s topological united K-theory. United K-theory incorporates three functors -- real K-theory, complex K-theory, and self-conjugate K-theory -- and the natural transformations among them. The advantage of united K-theory over ordinary K-theory lies in its homological algebraic propertie

  88. Helena Verrill, David Joyner

    These notes survey some basic results in toric varieties over a field with examples and applications. A computer algebra package (written by the second author) is described which deals with both affine and projective toric varieties in any number of dimensions (written in both the software packages MAGMA and GAP). Among other things, the package implements a

  89. Jean-Baptiste Gouéré

    Using the Palm measure notion, we prove the existence of the diffraction measure of all stationary and ergodic point processes. We get precise expressions of those measures in the case of specific processes : stochastic subsets of Z^d, sets obtained by the ``cut-and-project&#39;&#39; method.

  90. Parameswaran Sankaran

    We show that any two holomorhpic maps, not both of which are constant, from a generalized Hopf manifold to its base must have a coincidence. We prove a similar result for holomorphic maps from a generalized Calabi-Eckmann manifold.

  91. Toshiaki Shoji

    Let W be the complex reflection group G(e,1,n). In the author&#39;s previous paper, Hall-Littlewood functions associated to W were introduced. In the special case where W is a Weyl group of type B_n, they are closely related to Green polynomials of finite classical groups. In this paper, we introduce a two variables version of the above Hall-Littlewood funct

  92. Noam D. Elkies, Everett W. Howe, Andrew Kresch, Bjorn Poonen

    We resolve a 1983 question of Serre by constructing curves with many points of every genus over every finite field. More precisely, we show that for every prime power q there is a positive constant c_q with the following property: for every non-negative integer g, there is a genus-g curve over F_q with at least c_q * g rational points over F_q. Moreover, we

  93. Luis Gonzalez-Mestres

    Lorentz symmetry violation (LSV) can be generated at the Planck scale, or at some other fundamental length scale, and naturally preserve Lorentz symmetry as a low-energy limit (deformed Lorentz symmetry, DLS). DLS can have important implications for ultra-high energy cosmic-ray physics (see papers physics/0003080, astro-ph/0011181 and astro-ph/0011182, and r

  94. Robert Fleischer

    We give an overview of direct determinations of the angles of the unitarity triangle of the CKM matrix, using CP-violating effects in B-meson decays. After a discussion of B --> pi K modes, which can be described efficiently through allowed regions in observable space and play an important role to determine gamma, we turn to extractions of the B^0_d -- bar{B

  95. D. V. Shirkov

    The summary of nonperturbative results for the QCD invariant coupling bar{alpha}_s obtained by lattice simulations for functional integral and by solution of approximate Dyson--Schwinger equations reveals a puzzling variety of IR behavior of bar{alpha}_s(Q^2) even on a qualitative level. This, in turn, rises a question of correspondence between the results o

  96. I. I. Bigi

    Studying heavy flavour physics is driven by multiple motivations: to probe our theoretical control over QCD; enhance our information on gluon and sea quark structure functions; use heavy flavour production as signal for the onset of the quark-gluon plasma; revisit light flavour spectroscopy through the final states in heavy flavour decays; extract fundamenta

  97. Zheng Xiaoping, Yang Shuhua, Li Jiarong

    The quarks are regarded as quasiparticles, which acquire an effective mass generated by the interaction with the other quarks of the dense system. The bulk viscosity is re-expressed in the case of interacting strange quark matter. We find that the viscosity is a few ~ tens times larger than that of non-interacting quark gas due to the small correction of med

  98. Wolfhard Janke, Des Johnston, Ralph Kenna

    A recently developed technique to determine the order and strength of phase transitions by extracting the density of partition function zeroes (a continuous function) from finite-size systems (a discrete data set) is generalized to systems for which (i) some or all of the zeroes occur in degenerate sets and/or (ii) they are not confined to a singular line in

  99. D. J. Summers

    The first acceleration stage for this muon collider scenario includes twenty passes through a single two GeV Linac. Teardrop shaped arcs of 1.8 Tesla fixed field magnets are used at each end of the Linac. This dogbone geometry minimizes muon decay losses because muons pass through shorter arcs when their gamma boost is low. Two 2200 meter radius hybrid rings

  100. J. R. Batley, NA48 collaboration

    The direct CP violation parameter Re(epsilon&#39;/epsilon) has been measured from the decay rates of neutral kaons into two pions using the NA48 detector at the CERN SPS. The 2001 running period was devoted to collecting additional data under varied conditions compared to earlier years (1997-99). The new data yield the result: Re(epsilon&#39;/epsilon) = (13.