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February 1999 arXiv papers — page 7

Showing 601700 of 1,931 papers

  1. M. Jaime, R. Movshovich, J. L. Sarrao, J. Kim

    The new NHMFL 60T quasi-continuous magnet produces a flat-top field for a period of 100 ms at 60 Tesla, and for longer time at lower fields, e.g. 0.5 sec at 35 Tesla. We have developed for the first time the capability to measure heat capacity at very high magnetic fields in the NHMFL 60 T quasi-continuous magnet at LANL, using a probe built out of various p

  2. D. Mihailovic, J. Demsar

    Ultrafast time-resolved optical spectroscopy in high-temperature superconductors enables the direct real-time measurement of non-equilibrium quasiparticle recombination dynamics. In addition, it also gives detailed information about the symmetry of the superconducting gap and the "pseudogap", their doping dependence and their temperature dependence.

  3. Hugo Touchette

    This brief note argues that, contrary to the claim of Ishioka and Fuchikami (chao-dyn/9902012), Landauer's principle is concerned a priori with entropy generation in computing processes. The concept of heat, in this principle, is only relevant when a connection with thermodynamics is established.

  4. Sidney van den Bergh

    A new compilation of data on Local Group members shows that low-luminosity early-type galaxies are, at the 99% confidence level, more strongly concentrated in the M 31, and Galactic sub-clumps, than are dwarf irregular galaxies. It is not yet clear if star formation continued longer in dSph galaxies that are located far from M 31 and the Galaxy, than it did

  5. K. C. Roth, J. M. Bauer

    We report the detection of the 1560 A and 1657 A ground-state C I absorption features in the z(abs)=1.6748 system toward the QSO PKS 1756+237. We find no associated C I* lines with a resulting 3-sigma excitation temperature upper-limit of T(ex) <= 8.54 (+0.65,-0.56) K, which is consistent with the predicted CMBR temperature of T(CMBR)=7.291 K. Because the re

  6. V. Doublier, D. Kunth, F. Courbin, P. Magain

    High resolution, ground based R and I band observations of the ultra compact dwarf galaxy POX 186 are presented. The data, obtained with the ESO New Technology Telescope (NTT), are analyzed using a new deconvolution algorithm which allows one to resolve the innermost regions of this stellar-like object into three Super-Star Clusters (SSC). Upper limits to bo

  7. K. D. Borne, H. Bushouse, L. Colina, R. A. Lucas

    We have used the Hubble Space Telescope (HST) to study a large sample of ultraluminous IR galaxies (ULIRGs). With a rich legacy database of 150 high-resolution images, we are studying the fine-scale structure of this unique collection of violently starbursting systems. We review here some of the latest results from our survey. We present a simple morphologic

  8. Andy Lawrence

    The connection between normal and active galaxies is reviewed, by summarizing our progress on answering nine key questions. (1) Do all galaxies contain massive dark objects (MDOs)? (2) Are these MDOs actually supermassive black holes? (3) Why are the dark objects so dark? (4) Do all galaxies contain an Active Galactic Nucleus (AGN)? (5) Are the &#34;dwarf AG

  9. C. Clement, I. Shelton

    An examination of the period-V amplitude relation for RRab stars (fundamental mode pulsators) with `normal&#39; light curves in the Oosterhoff type I clusters M3 and M107 and in the Oosterhoff type II clusters M9 and M68 reveals that the V amplitude for a given period is not a function of metal abundance. Rather, it is a function of the Oosterhoff type. This

  10. Andrei Gruzinov

    We show that flows of pure electromagnetic energy are subject to instabilities familiar from hydrodynamics and plasma physics---Kelvin-Helmholtz and screw instabilities. In the framework of force-free electrodynamics, it is found that electric-like tangential discontinuities are Kelvin-Helmholtz-unstable. All non-trivial cylindrically symmetrical magnetic co

  11. H. K. C. Yee, Omar Lopez-Cruz

    Using photometric catalogs from wide-field CCD images, we derive the cluster-galaxy correlation amplitudes, Bgc, for 47 low-redshift Abell clusters. We apply a number of tests to establish the robustness of the Bgc parameter as a quantitative measure of richness of galaxy clusters. These include using different galaxy luminosity functions to normalize the ex

  12. F. Combes, R. Maoli, A. Omont

    Nearly 10 high redshift (z>2) starburst galaxies have recently been detected in the CO lines, revealing the early presence in the universe of objects with large amounts of already-enriched molecular gas. The latter has sufficient density to be excited in the high-level rotational CO lines, which yield more flux, making easier high-redshift detections; howeve

  13. D. Puy, L. Grenacher, P. Jetzer

    In many clusters of galaxies there is evidence for cooling flows in the central regions. The ultimate fate of the gas which cools is still unknown. A possibility is that a fraction of the gas forms cold molecular clouds. We investigate the minimum temperature which can be reached by clouds in cooling flows by computing the cooling function due to H2, HD and

  14. Jacco Th. van Loon, Albert A. Zijlstra, M. A. T. Groenewegen

    We present ground-based 3 micron spectra of obscured Asymptotic Giant Branch (AGB) stars in the Magellanic Clouds (MCs). We identify the carbon stars on the basis of the 3.1 micron absorption by HCN and C2H2 molecules. We show evidence for the existence of carbon stars up to the highest AGB luminosities (Mbol=-7 mag, for a distance modulus to the LMC of 18.7

  15. J. Knodlseder, D. Dixon, R. Diehl, U. Oberlack

    Deconvolving COMPTEL gamma-ray data into images presents a major methodological challenge. We developed a new algorithm called Multiresolution Regularized Expectation Maximization (MREM), which explicitly accounts for spatial correlations in the image by using wavelets (Dixon et al. 1998). We demonstrate that MREM largely suppresses image noise in the recons

  16. J. Knodlseder, R. Diehl, U. Oberlack, P. von Ballmoos

    We examined the question of a possible correlation between 1.8 MeV emission and intensity distributions observed at other wavelengths by comparing the 1.8 MeV data to an extended set of all-sky maps, covering the entire explored wavelength range from the radio band up to high-energy gamma-rays. This analysis revealed that tracers of the old stellar populatio

  17. Jurgen Knodlseder

    The comparison of COMPTEL 1.8 MeV gamma-ray line data to an extended data base of tracer maps revealed an extremely close correlation between 1.8 MeV gamma-ray line emission on the one side and 53 GHz microwave free-free emission and 158 um far-infrared line emission on the other side (Knodlseder et al., these proceedings). We demonstrate that the two tracer

  18. Altan Baykal, M. Ali Alpar, Paul E. Boynton, John E. Deeter

    We have investigated the stability of the pulse frequency second derivatives ($\ddot ν$) of PSR 0823+26, PSR 1706-16, PSR 1749-28, PSR 2021+51 which show significant quadratic trends in their pulse frequency histories in order to determine whether the observed second derivatives are secular or they arise as part of noise processes. We have used TOA data exte

  19. F. Caputo, V. Castellani, M. Marconi, V. Ripepi

    We present B and V CCD photometry for variables in the cluster central region, adding new data for 32 variables and giving suitable light curves, mean magnitudes and corrected colors for 17 RR Lyrae. Implementing the data given in this paper with similar data already appeared in the literature we discuss a sample of 42 variables, as given by 22 RRab and 20 R

  20. Takakuni Shimizu, Kazuya Watanabe

    We obtain a new expression of the Friedmann-Robertson-Walker metric, which is an analogue of a static chart of the de Sitter space-time. The reduced metric contains two functions, $M(T,R)$ and $Ψ(T,R)$, which are interpreted as, respectively, the mass function and the gravitational potential. We find that, near the coordinate origin, the reduced metric can b

  21. I. M. Gioia, J. P. Henry, C. R. Mullis, H. Ebeling

    Clusters of galaxies at redshifts nearing one are of special importance since they may be caught at the epoch of formation. At these high redshifts there are very few known clusters. We present follow-up ASCA, ROSAT HRI and Keck LRIS observations of the cluster RXJ1716.6+6708 which was discovered during the optical identification of X-ray sources in the Nort

  22. BATC Collaboration, Z. Y. Zheng, Z. H. Shang, H. J. Su

    We obtained very deep exposures of NGC 5907 with a Schmidt telescope, large-format CCD, and intermediate-band filters centered at 6660A and 8020A. These two filters, part of a 15-filter set, are custom-designed to avoid the brightest (and most variable) night sky lines, with the result that our images go deeper, with lower sky noise, than those taken with br

  23. Lam Hui

    Bernardeau et al. (1997), using perturbation theory, showed that the skewness of the large-scale lensing-convergence, or projected mass density, could be used to constrain $Ω_m$, the matter content of the universe. On the other hand, deep weak-lensing field surveys in the near future will likely measure the convergence on small angular scales (< 10 arcmin.),

  24. Soeren S. Larsen, Tom Richtler

    Using ground-based UBVRI+Halpha CCD photometry we have been carrying out a search for young massive star clusters (YMCs) in a sample consisting of 21 nearby spiral galaxies. We find a large variety concerning the richness of the cluster systems, with some galaxies containing no YMCs at all and others hosting very large numbers of YMCs. Examples of galaxies w

  25. H. F. Fong, P. Bourges, Y. Sidis, L. P. Regnault

    Many physical properties of the copper oxide high temperature superconductors appear to defy the conventional (one-electron) theory of metals, and the development of new theories incorporating strong electron correlations is currently at the forefront of condensed matter physics. Inelastic neutron scattering provides incisive information about collective mag

  26. J. J. Blanco-Pillado, R. A. Vázquez, E. Zas

    We discuss recent models in which neutrinos, which are assumed to have mass in the eV range, originate the highest energy cosmic rays by interaction with the enhanced density in the galactic halo of the relic cosmic neutrino background. We make an analytical calculation of the required neutrino fluxes to show that the parameter space for these models is cons

  27. A. Arbona, C. Bona, J. Masso, J. Stela

    The paper combines theoretical and applied ideas which have been previously considered separately into a single set of evolution equations for Numerical Relativity. New numerical ingredients are presented which avoid gauge pathologies and allow one to perform robust 3D calculations. The potential of the resulting numerical code is demonstrated by using the S

  28. Ernest Ma

    Extending the minimal standard model of particle interactions (without right-handed singlet neutrinos) to include a heavy scalar triplet $ξ$ to obtain nonzero Majorana neutrino masses, I derive the following simple realistic connection between atmospheric and solar neutrino vacuum oscillations: $(Δm^2)_{sol} (Δm^2)_{atm} / m_ν^4 ~(\sin^2 2 θ)_{atm} = 2 I^2$,

  29. Richard Berkovits

    The localization length of a low energy tightly bound electron-hole pair (excitons) is calculated by exact diagonalization for small interacting disordered systems. The exciton localization length (which corresponds to the thermal electronic conductance) is strongly enhanced by electron-electron interactions, while the localization length (pertaining to the

  30. R. D. Gill, S. Massar

    We consider the problem of estimating the state of a large but finite number $N$ of identical quantum systems. In the limit of large $N$ the problem simplifies. In particular the only relevant measure of the quality of the estimation is the mean quadratic error matrix. Here we present a bound on the mean quadratic error which is a new quantum version of the

  31. M. Magliocchetti, J. S. Bagla, S. J. Maddox, O. Lahav

    We study the observed evolution of galaxy clustering as a function of redshift. We find that the clustering of galaxies decreases as we go from observations of the local Universe to $z \sim 2$. On the other hand, clustering of the Lyman break galaxies at $z \sim 3$ is very strong, comparable to the clustering of present day galaxies. However there are three

  32. J. Fuchs, C. Schweigert

    We study conformally invariant boundary conditions that break part of the bulk symmetries. A general theory is developped for those boundary conditions for which the preserved subalgebra is the fixed algebra under an abelian orbifold group. We explicitly construct the boundary states and reflection coefficients as well as the annulus amplitudes. Integrality

  33. Amit Kundu, S. Mallik, D. Rai Chaudhuri

    Starting from an initial state of thermal equilibrium, we derive an expression for the quantum fluctuation in the energy density during the inflationary epoch in terms of the mode functions for the inflaton field. The effect of this particular initial state is not washed out in the final formula, contrary to what is usually believed. Numerically, however, th

  34. R. Ferlet

    Substantial progress in the field of the Local Interstellar Medium has been largely due to recent launches of space missions, mostly in the UV and X-ray domains, but also to ground-based observations, mainly in high resolution spectroscopy. However, a clear gap seems to remain between the wealth of new data and the theoretical understanding. This paper gives

  35. C. H. Ishwara-Chandra, D. J. Saikia

    We present multi-frequency VLA observations of two giant quasars, 0437-244 and 1025-229, from the Molonglo Complete Sample. These sources have well-defined FRII radio structure, possible one-sided jets, no significant depolarization between 1365 and 4935 MHz and low rotation measure ($\mid RM \mid < 20 rad/m^2$). The giant sources are defined to be those who

  36. Torsten Ekedahl, Sergei Lando, Michael Shapiro, Alek Vainshtein

    In this paper we find an explicit formula for the number of topologically different ramified coverings $C\to\CP^1$ (C is a compact Riemann surface of genus g) with only one complicated branching point in terms of Hodge integrals over the moduli space of genus g curves with marked points.

  37. Uriel Giveon, Dan Maoz, Shai Kaspi, Hagai Netzer

    We present results from a monitoring program of 42 quasars from the Palomar Green sample. The objects were observed for 7 years at the Wise Observatory, as part of a long term effort to monitor AGN of various types. This is the most extensive program of its kind carried out to date on a well-defined optically selected quasar sample. The typical sampling inte

  38. Jens L. Petersen

    These lectures do not at all provide a general review of this rapidly growing field. Instead a rather detailed account is presented of a number of the most elementary aspects.

  39. A. I. Yanson, I. K. Yanson, J. M. van Ruitenbeek

    The quantum states of a system of particles in a finite spatial domain in general consist of a set of discrete energy eigenvalues; these are usually grouped into bunches of degenerate or close-lying levels, called shells. In fermionic systems, this gives rise to a local minimum in the total energy when all the states of a given shell are occupied. In particu

  40. Mark Mineev-Weinstein, Oleg Kupervasser

    We study the exact non-singular zero-surface tension solutions of the Saffman-Taylor problem for all times. We show that all moving logarithmic singularities a_k(t) in the complex plane ω= e^{iϕ}, where ϕis the stream function, are repelled from the origin, attracted to the unit circle and eventually coalesce. This pole evolution describes essentially all th

  41. Kotaro Kohno, Ryohei Kawabe, Baltasar Vila-Vilaro

    High resolution (a few arcseconds) observations of CO(1-0) and HCN(1-0) emission from nearby Seyfert galaxies have been conducted with the Nobeyama Millimeter Array. Based on the observed CO distributions and kinematics,we suggest that a small scale (a few 100 pc - a few kpc) distortion of the underlying potential seems to be necessary for Seyfert activity,

  42. K. Sengupta, Victor. M. Yakovenko

    We show that a Hopf term exists in the effective action of long-wavelength skyrmions in quantum Hall systems for both odd integer and fractional filling factors $ν= 1/(2s +1)$, where $s$ is an integer. We evaluate the prefactor of the Hopf term using Green function method in the limit of strong external magnetic field using model of local interaction. The pr

  43. A. V. Taichenachev, A. M. Tumaikin, V. I. Yudin

    The motion of atoms in a dark magneto-optical lattice is considered. This lattice is formed by a non-uniformly polarized laser field in the presence of a static magnetic field. Cold atoms are localized in the vicinity of points where dark states are not destroyed by a magnetic field. As a result the optical interaction tends to zero (dark or gray lattices).

  44. Michael Byrne

    Einstein said that gravity is an acceleration like any other acceleration. But gravity causes relativistic effects at non-relativistic speeds; so gravity could have relativistic origins. And since the strong force is thought to cause most of mass, and mass is proportional to gravity; the strong force is therefore also proportional to gravity. The strong forc

  45. John Bahcall, Eli Waxman

    We elucidate the physical basis for the upper bound on high energy neutrino fluxes implied by the observed cosmic ray flux. We stress that the bound is valid for neutrinos produced either by p,gamma reactions or by p-p(n) reactions in sources which are optically thin for high energy protons to photo-meson and nucleon-meson interactions. We show that the uppe

  46. N. K. Bliev, G. N. Nugmanova, R. N. Syzdykova, R. Myrzakulov

    Soliton equations in 2+1 and their 1+1 = 2+0 reductions are considered.

  47. J. Harnad

    The Schwarzian equations satisfied by certain Hauptmoduls (i.e., uniformizing functions for Riemann surfaces of genus zero) are derived from the Picard-Fuchs equations for families of elliptic curves and associated surfaces. The inhomogeneous Picard-Fuchs equations associated to elliptic integrals with varying endpoints are derived and used to determine solu

  48. A. Vercin

    By making use of the Weyl-Wigner-Groenewold-Moyal association rules, a commutative product and a new quantum bracket are constructed in the ring of operators \cal{F}(H). In this way, an isomorphism between Lie algebra of classical observables (with Poisson bracket) and the Lie algebra of quantum observables with this new bracket is established. By these obse

  49. Robert R. Tucci

    We present a new algorithm for reducing an arbitrary unitary matrix U into a sequence of elementary operations (operations such as controlled-nots and qubit rotations). Such a sequence of operations can be used to manipulate an array of quantum bits (i.e., a quantum computer). Our algorithm applies recursively a mathematical technique called the CS Decomposi

  50. W. D. Ramsay

    We measure the difference in the scattering probability when an experiment scattering longitudinally polarized 221 MeV protons from liquid hydrogen is replaced by its mirror image. The result depends on the interplay between the weak and strong interactions in the interesting region near the surface of the proton. The experiment is technically very challengi

  51. J. H. Field

    The conventional discussion of apparent distortions of space and time in Special Relativity (the Lorentz-Fitzgerald Contraction and Time Dilatation) is extended by considering observations of : (i) moving objects of limited lifetime in their own rest frame (`transient luminous objects&#39;) and (ii) a moving extended array of synchronised `equivalent clocks&

  52. C. Kohl, G. F. Bertsch

    We investigate noncollinear effects in antiferromagnetically coupled clusters using the general, rotationally invariant form of local spin-density theory. The coupling to the electronic degrees of freedom is treated with relativistic non-local pseudopotentials and the ionic structure is optimized by Monte-Carlo techniques. We find that small chromium cluster

  53. P. S. Kamenov

    In this paper it is shown that if one accept assumption of de Broglie that &#34;unitary wave-particle&#34; exists simultaneously and this coexistence is real, then one can find the mean life time of the hydrogen atom of Bohr (intensities).

  54. P. Danielewicz

    Questions concerning nuclear phase transitions are addressed within the transport theory. The issue of thermal equilibrium in the region of the liquid-gas phase transition is investigated. Signatures of the transition to the quark-gluon plasma are looked for.

  55. E. Epelbaum, Ulf-G. Meißner

    We discuss charge symmetry and charge independence breaking in an effective field theory approach for few-nucleon systems. We systematically introduce strong isospin-violating and electromagnetic operators in the theory. The charge dependence observed in the nucleon-nucleon scattering lengths is due to one-pion exchange and one electromagnetic four-nucleon c

  56. Sergey V. Zuev

    Using geometric quantization procedure, the quantization of algebra of observables for physical system with Ricci-flat phase space is obtained. In the classical case the appointed physical system is reduced to harmonic oscillator when the one real parameter is vanished.

  57. V. Rivasseau

    These notes are the second part of a common course on Renormalization Theory given with Professor P. da Veiga at X Jorge Andre Swieca Summer School, Aguas de Lindoia, Brazil, February 7-12, 1999. I emphasize the rigorous non-perturbative or constructive aspects of the theory. The usual formalism for the renormalization group in field theory or statistical me

  58. A. Beauville

    This survey paper is devoted to Riemannian manifolds with special holonomy. To any Riemannian manifold of dimension n is associated a closed subgroup of SO(n), the holonomy group; this is one of the most basic invariants of the metric. A famous theorem of Berger gives a complete (and rather small) list of the groups which can appear. Surprisingly, the compac

  59. Lidia V. Veselova, Oleg E. Tikhonov

    We prove that an arbitrary Banach couple is uniquely determined by the collection of intermediate spaces that are interpolation spaces for the operators of rank one. From this we deduce a confirmation to the conjecture by Yu. A. Brudnyi and N.Ya. Kruglyak that a Banach couple is uniquely determined by the collection of all its interpolation spaces. Some rele

  60. Francesc Planas-Vilanova

    The purpose of this paper is to prove the following theorem of uniform Artin-Rees properties: Let $A$ be an excellent (in fact J-2) ring and let $N\subset M$ be two finitely generated $A$-modules such that ${\rm dim}(M/N)\leq 1$. Then there exists an integer $s\geq 1$ such that, for all integers $n\geq s$ and for all ideals $I$ of $A$, $I^{n}M\cap N=I^{n-s}(

  61. Kota Yoshioka

    We give some examples of isomorphisms of moduli of sheaves induced by Fourier-Mukai functor. As applications, we give another proof on deformation type of some moduli spaces of sheaves on abelian and K3 surfaces.

  62. Tetsuji Miwa, Yoshihiro Takeyama

    We write the integral formula of Tarasov-Varchenko type for the solutions to the quantum Knizhnik-Zamolodchikov associated with a tensor product the of vector representations of sl_n. We consider the case where the deformation parameter q satisfies |q|=1. We use the bosonization of the type II vertex operators in order to find the hypergeometric pairing in t

  63. Pavel Etingof, Shlomo Gelaki

    One of the classical notions of group theory is the notion of the exponent of a group. The exponent of a group is the least common multiple of orders of its elements. In this paper we generalize the notion of exponent to Hopf algebras. We give five equivalent definitions of the exponent. Two of them are: 1) the exponent of H equals the order of the Drinfeld

  64. Matthias Lesch, Markus J. Pflaum

    We identify Melrose&#39;s suspended algebra of pseudodifferential operators with a subalgebra of the algebra of parametric pseudodifferential operators with parameter space $\R$. For a general algebra of parametric pseudodifferential operators, where the parameter space may now be a cone $Γ\subset\R^p$, we construct a unique ``symbol valued trace&#39;&#39;,

  65. J. R. S. Nascimento, Inyong Cho, Alexander Vilenkin

    A charged superconductiong cosmic string produces an extremely large electric field in its vicinity. This leads to vacuum instability and to the formation of a charged vacuum condensate which screens the electric charge of the string. We analyze the structure of this condensate using the Thomas-Fermi method.

  66. N. Dorey, T. J. Hollowood, D. Tong

    We study N=(2,2) supersymmetric abelian gauge theories in two dimensions. The exact BPS spectrum of these models is shown to coincide with the spectrum of massive hypermultiplets of certain N=2 supersymmetric gauge theories in four dimensions. A special case of these results involves a surprising connection between four-dimensional N=2 SQCD with N colours an

  67. Alice Rogers

    Nonsingularity conditions are established for the BFV gauge-fixing fermion which are sufficient for it to lead to the correct path integral for a theory with constraints canonically quantized in the BFV approach. The conditions ensure that anticommutator of this fermion with the BRST charge regularises the path integral by regularising the trace over non-phy

  68. I. Brevik, A. A. Bytsenko, A. E. Goncalves

    Mass and decay spectra are calculated for quantum massive excitations of a piecewise uniform bosonic string. The physical meaning of the critical temperatures characterizing the radiation in the decay of a massive microstate in string theory is discussed.

  69. Janos Polonyi

    A c-number path integral representation is constructed for the solution of the Dirac equation. The integration is over the real trajectories in the continuous three-space and other two canonical pairs of compact variables controlling the spin and the chirality flips.

  70. Xiangdong Ji, Jonathan Osborne

    Working in the light-cone gauge, we find a simple procedure to calculate the autonomous one-loop Q^2 evolution of the twist-three part of the nucleon g_T(x, Q^2) structure function in the large-N_c limit. Our approach allows us to investigate the possibility of a similar large-N_c simplification for other higher-twist evolutions. In particular, we show that

  71. Manuel Drees, Oscar J. P. Eboli

    We discuss perturbative and non-perturbative strong interaction effects in the pair production of stop squarks ($\tilde{t}_1$) at $e^+ e^-$ colliders. Events with an additional hard gluon allow to detect or exclude stop pair production even in scenarios with very small mass splitting between $\tilde{t}_1$ and an invisible lightest supersymmetric particle (LS

  72. Herbert Weigel

    The computation of nucleon structure functions within the Nambu-Jona-Lasinio chiral soliton model is outlined. After some technical remarks on the issue of regularization numerical results for the both unpolarized and polarized structure functions are presented. The generalization to flavor SU(3) is sketched.

  73. C. Broggini, I. Masina, M. Moretti

    We discuss the size of the electron-antineutrino electron into electron-antineutrino electron cross section reduction due to the rejection of the events with a vertex bremsstrahlung photon above a certain energy in the final state. In particular we analyze the effect in experiments designed to detect the low energy electron-antineutrino and electron-neutrino

  74. Marco Ripani

    Decay of light quark excited baryons in the double pion channel is discussed, as a particular way of investigating poorly know baryon resonances and searching for &#34;missing states&#34; predicted by quark models. A possible approach to the data analysis is discussed and some preliminary data from the CLAS collaboration at Jefferson Laboratory are presented

  75. V. I. Yukalov

    Conditions are analysed when in dense and hot nuclear matter large amounts of Bose particles can be created. An intensive production of Bose particles is the main necessary condition for realizing their coherent emission similar to radiation from photon lasers. The consideration is based on the multichannel model of nuclear matter. Analysis shows that possib

  76. H. Nishiura, K. Matsuda, T. Fukuyama

    We propose a model that all quark and lepton mass matrices have the same zero texture. Namely their (1,1), (1,3) and (3,1) components are zeros. The mass matrices are classified into two types I and II. Type I is consistent with the experimental data in quark sector. For lepton sector, if seesaw mechanism is not used, Type II allows a large $ν_μ- ν_τ$ mixing

  77. Y. Kanazawa, Yuji Koike, N. Nishiyama

    We present a leading order (LO) estimate for the longitidinal-transverse spin asymmetry (A_{LT}) in the nucleon-nucleon polarized Drell-Yan process at RHIC and HERA-$\vec{N}$ energies in comparison with A_{LL} and A_{TT}. A_{LT} receives contribution from g_1, the transversity ditribution h_1, and the twist-3 distributions g_T and h_L. For the twist-3 contri

  78. F. Muheim

    Results from the four LEP experiments ALEPH, DELPHI, L3, and OPAL on the spectroscopy of B and charmed mesons are presented. The predictions of Heavy Quark Effective Theory (HQET) for the masses and the widths of excited L=1 B mesons are supported by a new measurement from L3. A few B_c candidate eve nts have masses consistent with the recent CDF observation

  79. Amos Ori

    Recently Nolan constructed a spherically-symmetric spacetime admitting a spacelike curvature singularity with a regular C^0 metric. We show here that this singularity is in fact weak.

  80. Anderson Ilha, Antares Kleber, Jose&#39; P. S. Lemos

    The Lovelock gravity extends the theory of general relativity to higher dimensions in such a way that the field equations remain of second order. The theory has many constant coefficients with no a priori meaning. Nevertheless it is possible to reduce them to two, the cosmological constant and Newton&#39;s constant. In this process one separates theories in

  81. Lee Lindblom, Gregory Mendell, Benjamin J. Owen

    Techniques are developed here for evaluating the r-modes of rotating neutron stars through second order in the angular velocity of the star. Second-order corrections to the frequencies and eigenfunctions for these modes are evaluated for neutron star models. The second-order eigenfunctions for these modes are determined here by solving an unusual inhomogeneo

  82. Rafael Sorkin, Daniel Sudarsky

    We evoke situations where large fluctuations in the entropy are induced, our main example being a spacetime containing a potential black hole whose formation depends on the outcome of a quantum mechanical event. We argue that the teleological character of the event horizon implies that the consequent entropy fluctuations must be taken seriously in any interp

  83. John W. Barrett, Ruth M. Williams

    An expression for the oscillatory part of an asymptotic formula for the relativistic spin network amplitude for a 4-simplex is given. The amplitude depends on specified areas for each two-dimensional face in the 4-simplex. The asymptotic formula has a contribution from each flat Euclidean metric on the 4-simplex which agrees with the given areas. The oscilla

  84. Amandine Aftalion, William C. Troy

    This paper gives a complete description of the solutions of the one dimensional Ginzburg-Landau equations which model superconductivity phenomena in infinite slabs. We investigate this problem over the entire range of physically important parameters: $a$ the size of the slab, $κ$ the Ginzburg-Landau parameter, and $h_0$, the exterior magnetic field. We do ex

  85. Sergei Sergeenkov, Marcel Ausloos

    We start with revisiting our previous results on thermoelectric response of SNS configuration in a C-shaped Bi(x)Pb(1-x)Sr(2)CaCu(2)O(y) sample in order to include strong fluctuation effects. Then, by appropriate generalization of the Ginzburg-Landau theory based on admixture of s-wave and d-wave superconductors, we consider a differential thermoelectric pow

  86. Paul N. Walker, Gilles Montambaux, Yuval Gefen

    We investigate the addition spectrum of disordered quantum dots containing spinless interacting fermions using the self-consistent Hartree-Fock approximation. We concentrate on the regime r_s >~1, with finite dimensionless conductance g. We find that in this approximation the peak spacing fluctuations do not scale with the mean single particle level spacing

  87. V. I. Yukalov

    A system of resonance atoms is placed in a medium with developed polariton effect. In the spectrum of polariton states there can exist a band gap. If an atom with a resonance frequency inside the polariton gap is incorporated into the medium, the atomic spontaneous emission can be strongly suppressed. This is what is called the localization of light. Neverth

  88. Gen Tatara, Hidetoshi Fukuyama

    The resistivity of disordered metallic layer sandwiched by two ferromagnetic layers at low-temperature is investigated theoretically. It is shown that the magnetic field acting at the interface does not affect the classical Boltzmann resistivity but causes a dephasing among electrons in the presence of the spin-orbit interaction, suppressing the anti-localiz

  89. Masa-aki Ozaki, Yoshiki Hori, Akira Goto

    This paper gives a new refined definition of local symmetric order parameters (OPs)(s-wave, d-wave and p-wave order parameters) of vortex lattice states for singlet superconductivity. s-wave, d-wave and p-wave OPs at a site (m,n) are defined as A, B and E representations of the four fold rotation C_4 at the site (m,n) of nearest neighbor OPs <a_{(m,n)\downar

  90. H. Fujioka, M. Kubota, K. Hirota, H. Yoshizawa

    Inelastic neutron-scattering measurements were performed on a single crystal of the layered colossal magnetoresistance (CMR) material La1.2Sr1.8Mn2O7 (Tc ~ 120K). We found that the spin wave dispersion is almost perfectly two-dimensional with the in-plane spin stiffness constant D ~ 151meVA. The value is similar to that of similarly doped La1-xSrxMnO3 though

  91. Beat Ammon, Manfred Sigrist

    One-dimensional Heisenberg spin 1/2 chains with random ferro- and antiferromagnetic bonds are realized in systems such as $Sr_3 CuPt_{1-x} Ir_x O_6$. We have investigated numerically the thermodynamic properties of a generic random bond model and of a realistic model of $Sr_3 CuPt_{1-x} Ir_x O_6$ by the quantum Monte Carlo loop algorithm. For the first time

  92. I. Tsukada, Y. Sasago, K. Uchinokura, A. Zheludev

    The new antiferromagnetic (AF) compound BaCu_2Si_2O_7 is studied by magnetic susceptibility and neutron scattering techniques. The observed behavior is dominated by the presence of loosely coupled S=1/2 chains with the intrachain AF exchange constant J = 24.1 meV. Long-range Neel ordering is observed below Tn = 9.2 K. The results are discussed within the fra

  93. T. M. R. Byrnes, M. T. Murphy, O. P. Sushkov

    Based on the Majumdar-Ghosh chain we construct several spin models which allow us to investigate spinon dynamics in the regime close to deconfinement of spinons. We consider the J_1 - J_2 - δmodel, two coupled J_1 - J_2 chains (ladder), and a 2D array of coupled J_1 - J_2 chains. Using the picture of two spinons interacting with a string confining potential

  94. Adriana Moreo, Seiji Yunoki, Elbio Dagotto

    Recent computational studies of models for manganese oxides have revealed a rich phase diagram, not anticipated in early calculations in this context performed in the 1950&#39;s and 60&#39;s. In particular, the transition between the antiferromagnetic insulator state of the hole-undoped limit and the ferromagnetic metal at finite hole-density was found to oc

  95. A. Campbell-Smith, N. E. Mavromatos

    These lectures serve as an introduction to the renormalization group approach to effective field theories, with emphasis on systems with a Fermi surface. For such systems, demanding appropriate scaling with respect to the renormalization group for the appropriate excitations leads directly to the important concept of quasiparticles and the connexion between

  96. Indubala I. Satija, Bala Sundaram, Jukka A. Ketoja

    We address the issue of fluctuations, about an exponential lineshape, in a pair of one-dimensional kicked quantum systems exhibiting dynamical localization. An exact renormalization scheme establishes the fractal character of the fluctuations and provides a new method to compute the localization length in terms of the fluctuations. In the case of a linear ro

  97. Shiyi Chen, Darryl D. Holm, Len G. Margolin, Raoyang Zhang

    We explore the utility of the recently proposed alpha equations in providing a subgrid model for fluid turbulence. Our principal results are comparisons of direct numerical simulations of fluid turbulence using several values of the parameter alpha, including the limiting case where the Navier-Stokes equations are recovered. Our studies show that the large s

  98. F. Bertola, E. M. Corsini, M. Cappellari, J. C. Vega Beltran

    We report the case of the geometrical and kinematical decoupling between the bulge and the disk of the Sa galaxy NGC 4698. The R-band isophotal map of this spiral shows that the bulge structure is elongated perpendicularly to the major axis of the disk. At the same time a central stellar velocity gradient is found along the major axis of the bulge. We also p

  99. E. M. Corsini, F. Bertola, M. Sarzi, P. Cinzano

    The kinematics of stars and ionized gas has been studied near the center of the S0 galaxy NGC 4036. Dynamical models based both on stellar photometry and kinematics have been built in order to derive the gravitational potential in which the gas is expected to orbit. The observed gas rotation curve falls short of the circular velocity curve inferred from thes

  100. K. A. Weaver, A. S. Wilson, C. Henkel, J. A. Braatz

    We examine the 0.1 to 10.0 keV X-ray spectrum of the bright nuclear LINER galaxy NGC 1052, one of two elliptical galaxies known to contain a luminous H2O maser. The observed 2.0-10.0 keV spectrum is unusually flat (photon index Gamma~0.2) and best described as intrinsically power-law shaped nuclear flux that is either (1) attenuated by a complex absorber wit