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July 2000 arXiv papers — page 12

Showing 1,101–1,200 of 2,447 papers

  1. Kimberly C. B. New, Dae-Il Choi, Joan M. Centrella, Peter MacNeice

    Adaptive techniques are crucial for successful numerical modeling of gravitational waves from astrophysical sources such as coalescing compact binaries, since the radiation typically has wavelengths much larger than the scale of the sources. We have carried out an important step toward this goal, the evolution of weak gravitational waves using adaptive mesh

  2. John Ellis, N. E. Mavromatos, D. V. Nanopoulos

    In the context of non-critical Liouville strings, we clarify why we expect non-quantum-mechanical dissipative effects to be of order E^2/M_P, where E is a typical energy scale of the probe, and M_P is the Planck scale. In Liouville strings, energy is conserved {\it at best} only as a statistical average, as distinct from Lindblad systems, where it is {\it st

  3. Kur. Myrzakul, R. Myrzakulov

    Some aspects of multidimensional soliton geometry are considered.

  4. A. G. Agnese, M. La Camera

    The exterior and interior Schwarzschild solutions are rewritten replacing the usual radial variable with an angular one. This allows to obtain some results otherwise less apparent or even hidden in other coordinate systems.

  5. M. J. Reboucas

    A statistical quantity suitable for distinguishing simply-connected Robertson-Walker (RW) universes is introduced, and its explicit expressions for the three possible classes of simply-connected RW universes with an uniform distribution of matter are determined. Graphs of the distinguishing mark for each class of RW universes are presented and analyzed.There

  6. Scott H. Hawley, Matthew W. Choptuik

    We present a study of black hole threshold phenomena for a self-gravitating, massive complex scalar field in spherical symmetry. We construct Type I critical solutions dynamically by tuning a one-parameter family of initial data composed of a boson star and a massless real scalar field. The real field is used to perturb the boson star via a gravitational int

  7. Po-Han Lin

    All the current modern encryption algorithms utilize fixed symbols for plaintext and cyphertext. What I mean by fixed is that there is a set and limited number of symbols to represent the characters, numbers, and punctuations. In addition, they are usually the same (the plaintext symbols have the same and equivalent counterpart in the cyphertext symbols). Al

  8. M. Baranger, V. Latora, A. Rapisarda

    We consider several low--dimensional chaotic maps started in far-from-equilibrium initial conditions and we study the process of relaxation to equilibrium. In the case of conservative maps the Boltzmann-Gibbs entropy S(t) increases linearly in time with a slope equal to the Kolmogorov-Sinai entropy rate. The same result is obtained also for a simple case of

  9. F. Schmid, N. B. Wilding

    We study the wetting behaviour of a symmetrical binary fluid below the demixing temperature at a non-selective attractive wall. Although it demixes in the bulk, a sufficiently thin liquid film remains mixed. On approaching liquid/vapour coexistence, however, the thickness of the liquid film increases and it may demix and then wet the substrate. We show that

  10. R. A. Serota

    We argue that at zero temperature an isolated metal particle (or an AB ring) with spin-orbit interaction and odd number of electrons will have a permanent magnetic moment, even in zero magnetic field (flux). In a zero-field-cooled state both the direction and the magnitude of the moment varies from particle to particle and averages to zero. In a field-cooled

  11. V. Kiryukhin, B. G. Kim, V. Podzorov, S-W. Cheong

    The insulator-metal transition in single crystal La(5/8-y)Pr(y)Ca(3/8)MnO3 with y=0.35 was studied using synchrotron x-ray diffraction, electric resistivity, magnetic susceptibility, and specific heat measurements. Despite the dramatic drop in the resistivity at the insulator-metal transition temperature Tmi, the charge-ordering (CO) peaks exhibit no anomaly

  12. V. N. Gladilin, V. M. Fomin, J. T. Devreese

    We extend the theory of the surface-induced magnetic anisotropy to mesoscopic samples with arbitrary geometry. The shape-induced anisotropy of impurity spins in small brick-shaped grains of dilute magnetic alloys is studied in detail. The surface-induced blocking of a magnetic-impurity spin is shown to be very sensitive to geometric parameters of a grain. Th

  13. G. Finkelstein, P. I. Glicofridis, R. C. Ashoori, M. Shayegan

    A scanning probe technique was used to obtain a high-resolution map of the random electrostatic potential inside the quantum Hall liquid. A sharp metal tip, scanned above a semiconductor surface, sensed charges in an embedded two-dimensional electron gas. Under quantum Hall effect conditions, applying a positive voltage to the tip locally enhanced the 2D ele

  14. B. Barbiellini

    Summary for the review talk on recent progress in the theoretical studies of electron momentum density distribution at the Sagamore XIII conference (Stare Jablonki, Poland; September 3-9, 2000).

  15. Nick E. Mavromatos, Sarben Sarkar

    Using a SU(2)x U(1) gauge theory for a t-J model around a node of the Fermi surface, we discuss patterns of dynamical symmetry breaking, which may lead to a pseudogap phase and to the appearance of narrow one-dimensional spatial structures, induced by the presence of holes. A possible connection with stripe phases is briefly discussed by passing to an approp

  16. Ilya L . Kurland, Richard Berkovits, Boris L. Altshuler

    We study the influence of moderate exchange interactions of electrons on the behavior of the peaks in the conductance of single electron transistors. We numerically reproduce recently observed features of both the peak positions and the peak heights magnetic field dependence. These features unambiguously identify the total spin $S$ of each ground state. We e

  17. Martin D. Weinberg

    Using the theory describing the evolution of a galaxy halo due to stochastic fluctuations developed in the companion paper, we show that a halo quickly evolves toward the same self-similar profile, independent of its initial profile and concentration. The self-similar part of profile takes the form of a double power law with inner and outer exponents taking

  18. Martin D. Weinberg

    We present a theory for describing the evolution of a galaxy caused by stochastic events such as weak mergers, transient spiral structure, orbiting blobs, etc. This noise excites large-scale patterns that drives the evolution of the galactic density profile. In dark-matter haloes, the repeated stochastic perturbations preferentially ring the lowest-order mod

  19. D. K. Galloway

    X-ray observations of the binary pulsar GX 1+4 made using the Rossi X-ray Timing Explorer (RXTE) satellite between February 1996 and May 1997 were analysed to quantify source spectral variation with luminosity. Mean Proportional Counter Array (PCA) spectra over the range 2-40 keV are best fitted with a Comptonization model, with source spectrum temperature T

  20. R. Ramaty, B. Kozlovsky, R. E. Lingenfelter

    Employing a Monte-Carlo based evolutionary code, we show that the delay of Fe deposition relative to O, due to the incorporation of supernova ejecta refractories in high velocity grains, can account for the rise of [O/Fe] with decreasing [Fe/H]. The predicted behavior of refractory Mg, Si, Ca and Ti, and volatile S, namely that the refractories should not sh

  21. G. Kovacs

    We employ the very recent photometric data of the OGLE project together with stellar atmosphere and linear pulsation models to determine the distance modulus of the Small Magellanic Cloud from its double-mode Cepheids. Based on the requirement of obtaining the same distance modulus DM from the two types of variables (fundamental & first overtone and first &

  22. A. Gil de Paz, J. Zamorano, J. Gallego

    In this paper, continuation of Gil de Paz et al. (Paper I), we derive the main properties of the stellar populations in the Blue Compact Dwarf galaxy Mrk86. Ages, stellar masses, metallicites and burst strengths have been obtained using the combination of Monte Carlo simulations, a maximum likelihood estimator and Cluster and Principal Component Analysis. Th

  23. Eric Agol, Barbara Jones, Omer Blaes

    Using the Long Wavelength Spectrometer on Keck I, we have imaged the gravitationally lensed radio quiet quasi-stellar object (QSO) 2237+0305 at 8.9 and 11.7 microns for the first time. The mid-infrared flux ratios are inconsistent with the optical flux ratios, but agree with the radio flux ratios and with some published gravitational lens models. These flux

  24. E. Pian, L. Chiappetti, P. Giommi, F. Tavecchio

    We present the preliminary results of a long BeppoSAX observation of the BL Lac object Mkn501 carried out in June 1999. The source was fainter than found during the BeppoSAX pointings of 1997 and 1998, but is still detected with a good signal-to-noise ratio up to ~40 keV. The X-ray spectrum in the energy range 0.1-40 keV, produced through synchrotron radiati

  25. A. Gil de Paz, J. Zamorano, J. Gallego, F. de B. Dominguez

    We have obtained optical (BVR, [OIII]5007 and Halpha), near infrared (JHK) imaging and long-slit optical spectroscopy for the Blue Compact Dwarf galaxy Mrk86 (NGC2537). In this paper, the first of two, we present optical-near- infrared colors and emission-line fluxes for the currently star-forming regions, intemediate aged starburst and underlying stellar po

  26. E. Vesperini

    We study the evolution of globular cluster systems (GCS) in elliptical galaxies and explore the dependence of their main properties on the mass and the size of the host galaxy.The dependence of the evolution of the GCS mass function (GCMF), of the fraction of surviving clusters and of the ratio of the final to initial mass in clusters on the structure of the

  27. C. Adami, M. Ulmer

    We investigate in this paper the error on the cluster redshift estimate as a function of: (1) the number of galaxy structures along the line of sight; (2) the morphology of the clusters (regular/substructures); (3) the nature of the observed galaxies (cD/normal galaxies); (4) the number of observed galaxies; and (5) the distance of the clusters. We find that

  28. Stefanie Komossa, D. Grupe, V. Burwitz, M. Janek

    We present an optical and X-ray study of the quasar QSO 0117-2837. It exhibits an interesting combination of optical and X-ray properties: Despite its extremely steep observed X-ray spectrum (Gamma_x ~ -4 when fit by a simple powerlaw), its Balmer lines are fairly broad. A two-component Gaussian fit to H_beta yields FWHM_{Hbeta, broad} ~ 4000 km/s, and place

  29. Christian R. Kaiser

    A 3-dimensional model of the synchrotron emissivity of the cocoons of powerful extragalactic radio sources of type FRII is constructed. Bulk backflow and energy losses of the relativistic electrons, radiative and adiabatic, are self-consistently taken into account. Thus the model is an extension of spectral aging methods including the underlying source dynam

  30. M. J. Hardcastle, D. M. Worrall

    Using ROSAT observations, we estimate gas pressures in the X-ray-emitting medium surrounding 63 FRII radio galaxies and quasars. We compare these pressures with the internal pressures of the radio-emitting plasma estimated by assuming minimum energy or equipartition. In the majority of cases (including 12/13 sources with modelled, spatially resolved X-ray em

  31. S. K. Chakrabarti

    Since black holes are `black', methods of their identification must necessarily be indirect. Due to very special boundary condition on the horizon, the advective flow behaves in a particular way, which includes formation of centrifugal pressure dominated boundary layer or CENBOL where much of the infall energy is released and outflows are generated. The

  32. Ortwin Gerhard

    This review discusses (i) dynamical methods for determining the masses of Galactic and extragalactic star clusters, (ii) dynamical processes and their time-scales for the evolution of clusters, including evaporation, mass segregation, core collapse, tidal shocks, dynamical friction and merging. These processes lead to significant evolution of globular cluste

  33. B. Aschenbach, U. Briel, F. Haberl, H. Braeuninger

    The in-orbit imaging performance of the three X-ray telescopes on board of the X-ray astronomy observatory XMM-Newton is presented and compared with the performance measured on ground at the MPE PANTER test facility. The comparison shows an excellent agreement between the on ground and in-orbit performance.

  34. P. Meszaros, A. Gruzinov

    For Gamma-Ray Bursts occurring in dense star-forming regions, the X-ray afterglow behavior minutes to days after the trigger may be dominated by the small-angle scattering of the prompt X-ray emission off dust grains. We give a simple illustrative model for the X-ray light curves at different X-ray energies, and discuss possible implications. A bump followed

  35. S. K. Chakrabarti

    Ten years have passed since the global solutions of advective accretion disks around black holes and neutron stars were first discovered. Since then they are enjoying support from observers almost on a daily basis, more so in recent days with the launching of very high resolution satellites. This review presents the development of the subject of advective ac

  36. Sandip K. Chakrabarti, Banibrata Mukhopadhyay

    Chandrasekhar separated the Dirac equation for spinning and massive particles in Kerr geometry into radial and angular parts. In the present review, we present solutions of the complete wave equation and discuss how the Dirac wave scatters off Kerr black holes. The eigenfunctions, eigenvalues and reflection and transmission co-efficients are computed for dif

  37. T. Treu, M. Stiavelli, S. Casertano, P. Moller

    We present preliminary results on the evolution of the stellar populations of field early-type galaxies (E/S0) from z=0.4 to z=0. The diagnostic tool used in this study is the Fundamental Plane (FP), a tight empirical correlation between their central velocity dispersion (sigma), effective radius (Re), and effective surface brightness (SBe), which is observe

  38. S. Sarala, Pankaj Jain

    We propose a new method for the extraction of Rotation Measure from spectral polarization data. The method is based on maximum likelihood analysis and takes into account the circular nature of the polarization data. The method is unbiased and statistically more efficient than the standard $χ^2$ procedure. We also find that the method is computationally much

  39. A. R. Rao, J. S. Yadav, B. Paul

    We examine the X-ray spectral and temporal behavior of the Galactic black hole candidate source GRS 1915+105 during its spectral state transition observed in 1997 March - August. The source was making a slow transition from a low-hard state to a high-soft state in about three months and during this transition it was exhibiting a series of fast variations whi

  40. R. Brent Tully

    Two curiously connected topics provided a novel focus for this meeting in Guanajuato, Mexico, 22--29, February, 2000. Two days were devoted to discussions of galaxy surveys deep into the Galactic plane and to modeling of the distribution of matter that makes use of quasi-full-sky coverage. Then the meeting turned its attention for four further days to a look

  41. Saurabh Jha, David Charbonneau, Peter M. Garnavich, Denis J. Sullivan

    We present B, V, R, I and Z-band photometric observations of HD 209458 during the transit by its planetary companion on UT 1999 November 15 with the University of Hawaii 0.6m and 2.2m telescopes and the High Altitude Observatory STARE telescope. The detailed shape of the transit curve is predicted to vary with color due primarily to the color-dependent limb-

  42. J. S. Bloom, S. G. Djorgovski, S. R. Kulkarni

    The gamma-ray burst of 28 February 1997 (GRB 970228) ushered in the discovery of the afterglow phenomenon. Despite intense study of the host galaxy, however, the nature of the host and the distance to the burst eluded the community. Here we present the measurement of the redshift of GRB 970228, and, based on its spectroscopic and photometric properties, iden

  43. M. J. Duff, James T. Liu, K. S. Stelle

    We show that an earlier domain wall solution of type IIB supergravity provides a supersymmetric realization of the Randall-Sundrum brane-world, and give its ten-dimensional interpretation in terms of IIB 3-branes. We also explain how previous no-go theorems are circumvented. In particular, whereas D=5 supergravity scalars have AdS_5 energy E_0 <= 4 and are u

  44. F. del Aguila, M. Perez-Victoria, J. Santiago

    We use the effective Lagrangian formalism to describe quark mixing. The new W, Z and H couplings generalizing the CKM matrix and the GIM mechanism fulfil relations and inequalities which allow to discriminate among different SM extensions. As a by-product we give a useful parametrization of the generalized CKM matrix. We also show that the largest possible d

  45. R. Giacconi, P. Rosati, P. Tozzi, M. Nonino

    We present our first results from 130 ks of X-ray observations obtained with the Advanced CCD Imaging Spectrometer on the Chandra X-ray Observatory. We reach a flux of 2 X 10^(-16) erg s^(-1) cm^(-2) in the 0.5-2 keV soft band and 2 X 10^(-15) erg s^(-1) cm^(-2) in the 2-10 keV hard band. For the optical identification we carried out a survey in VRI with the

  46. W. de Boer, V. Bartsch, J. Bol, A. Dierlamm

    Future experiments are using silicon detectors in a high radiation environment and in high magnetic fields. The radiation tolerance of silicon improves by cooling it to temperatures below 180 K. At low temperatures the mobility increases, which leads to larger deflections of the charge carriers by the Lorentz force. A good knowledge of the Lorentz angle is n

  47. Roger Ellman

    -The favored Big Bang concept is that the original symmetry was skewed, the universe now being all matter, all antimatter having annihilated. -The mechanism of matter/antimatter annihilation is analyzed. A total annihilation of original antimatter could not have occurred; the skewing is unnecessary; and the universe must contain equally both forms of matter.

  48. Jialun Ping, Fan Wang, T. Goldman

    The mass estimate of the $d^* (IJ^P=03^+)$ dibaryon is improved by a dynamical calculation in the quark delocalization, color screening model. The partial decay width of $d^*$ into an $NN$ D-wave state is also obtained. The mass obtained is slightly larger than that obtained in adiabatic calculations, due to the anharmonicity of the effective potential betwe

  49. M. J. Collinge, W. N. Brandt

    We present analyses of the ASCA X-ray spectra of two Seyfert galaxies, Tololo 0109-383 and ESO 138-G1. In both cases, spectral fitting reveals two statistically acceptable continuum models: Compton reflection and partial covering. Both spectra have strong iron K-alpha lines, with equivalent widths greater than 1.5 keV. These large equivalent widths are sugge

  50. S. L. Dubovsky, V. A. Rubakov, P. G. Tinyakov

    We discuss whether electric charge conservation may not hold in four-dimensional world in models with infinite extra dimensions, i.e., whether escape of charged particles from our brane is consistent with effectively four-dimensional electrodynamics on the brane. We introduce a setup with photon localized on the brane and show that charge leakage into extra

  51. D. Atwood, C. P. Burgess, E. Filotas, F. Leblond

    Recently, a scenario has been proposed in which the gravitational scale could be as low as the TeV scale, and extra dimensions could be large and detectable at the electroweak scale. Although supersymmetry is not a requirement of this scenario, it is nevertheless true that its best-motivated realizations arise in supersymmetric theories (like M theory). We a

  52. Fernando Abadie

    We show that any continuous partial action on a topological space has a unique enveloping action, i.e. it is the restriction of a global action. In the case of C^*-algebras we prove that any partial action has an enveloping action up to Morita equivalence. The study of enveloping actions up to Morita equivalence reveals the form that Takai duality takes for

  53. Avijit Mukherjee, Rula Tabbash

    We point out geometric upper and lower bounds on the masses of bosonic and fermionic Kaluza-Klein excitations in the context of theories with large extra dimensions. The characteristic compactification length scale is set by the diameter of the internal manifold. Based on geometrical and topological considerations, we find that certain choices of compactific

  54. S. Botti, A. Rosso, R. Santachiara, F. Tedoldi

    The response of an open spin chain with isotropic antiferromagnetic interactions to a uniform magnetic field is studied by classical Monte Carlo simulations. It is observed how the induced on-site magnetization is non uniform, due to the occurrence of edge staggered terms which decay exponentially over a distance equal to the zero field correlation length of

  55. Mark Sullivan, Richard Ellis, Peter Nugent, Ian Smail

    Distant Type Ia and II supernovae (SNe) can serve as valuable probes of the history of the cosmic expansion and star formation, and provide important information on their progenitor models. At present, however, there are few observational constraints on the abundance of SNe at high redshifts. A major science driver for the Next Generation Space Telescope (NG

  56. C. Duerr, S. Legner, R. Hayn, S. V. Borisenko

    We have investigated the lowest binding-energy electronic structure of the model cuprate Sr_2CuO_2Cl_2 using angle resolved photoemission spectroscopy (ARPES). Our data from about 80 cleavages of Sr_2CuO_2Cl_2 single crystals give a comprehensive, self-consistent picture of the nature of the first electron-removal state in this model undoped CuO_2-plane cupr

  57. Leopoldo A. Pando Zayas

    We provide a class of nondilatonic solutions to the NS-NS sector of string theory. The solutions consist of products of Ricci-parallelizable spaces with adjusted radii. A representative of this class, AdS_3 x S^7, is presented in detail. Some comments on possible brane connections are made.

  58. Mattias Marklund, Peter K. S. Dunsby, Gert Brodin

    We consider the dynamics of electromagnetic fields in an almost-Friedmann-Robertson-Walker universe using the covariant and gauge-invariant approach of Ellis and Bruni. Focusing on the situation where deviations from the background model are generated by tensor perturbations only, we demonstrate that the coupling between gravitational waves and a weak magnet

  59. B. Pötter

    We present a method to combine next-to-leading order (NLO) matrix elements in QCD with leading logarithmic parton showers by applying a suitably modified version of the phase-space-slicing method. The method consists of subsuming the NLO corrections into a scale-dependent phase-space-slicing parameter, which is then automatically adjusted to cut out the lead

  60. B. L. G Bakker, A. I. Veselov, M. A. Zubkov

    We consider the SU(2) lattice gauge model. We propose a new gauge invariant definition of center projection, which we call the Simple Center Projection. We demonstrate the center dominance, i.e., the coincidence of the projected potential with the full potential up to the mass renormalization term at low energies. We also consider the center vortices and the

  61. C. P. Martin, F. Ruiz Ruiz

    U(1) gauge theory on non-commutative Minkowski space-time in the Feynman-&#39;t Hooft background gauge is studied. In particular, UV divergences and non-commutative IR divergent contributions to the two, three and four-point functions are explicitly computed at one loop. We show that the negative sign of the beta function results from paramagnetism --produci

  62. Sven Bergmann, Gilad Perez

    Including the recent preliminary results of BaBar and BELLE experiments, we update the currently allowed intervals for various CKM parameters: $\bar\rho$, $\bar\eta$, $\sin2\beta$, $\sin2\alpha$, $\sin^2\gamma$. We also update the SM prediction for the rates of the $K_L \to \pi^0 \nu \bar\nu$ and $K^+ \to \pi^+ \nu \bar\nu$ decays, their ratio $a_{\pi \nu \b

  63. M. A. Ivanov, J. G. Korner, P. Santorelli

    We study the semileptonic transitions B_c to η_c, J/ψ, D, D^*, B, B^*, B_s, B_s^* in the framework of a relativistic constituent quark model. We use experimental data on leptonic J/ψdecay, lattice and QCD sum rule results on leptonic B_c decay, and on radiative η_c transitions to adjust the quark model parameters. We compute all form factors of the above sem

  64. V. P. Gusynin, V. M. Loktev, R. M. Quick, S. G. Sharapov

    The effect of ordering field phase fluctuations on the normal and superconducting properties of a simple 2D model with a local four-fermion attraction is studied. Neglecting the coupling between the spin and charge degrees of freedom an analytical expression has been obtained for the fermion spectral function as a single integral over a simple function. From

  65. Nobuki Maeda

    We study a pairing mechanism for the quantum Hall system using a mean field theory with a basis on the von Neumann lattice, on which the magnetic translations commute. In the Hartree-Fock-Bogoliubov approximation, we solve the gap equation for spin-polarized electrons at the half-filled Landau levels. We obtain an effective Hamiltonian which shows a continuo

  66. Peter Kopietz

    We calculate the two-loop renormalization group (RG) beta-function of a massless scalar field theory from the irreducible version of Polchinski&#39;s exact RG flow equation. To obtain the correct two-loop result within this method, it is necessary to take the full momentum-dependence of the irreducible four-point vertex and the six-point vertex into account.

  67. R. Horvat

    For any realistic theory of quintessence that allows for a violation of the equivalence principle (VEP), we study the experimental constraints on such theories coming from ordinary matter as well as neutrinos. We discuss and compare constraints from two basically different (extra) contributions to differences of fermion masses: one is due to the vacuum expec

  68. Corneliu Sochichiu

    Here we construct a map from the algebra of fields in two-dimensional noncommutative of U(1) Yang-Mills fields interacting with Kaluza-Klein scalars to a D-dimensional one, as a solution in the two-dimensional model. This proves the equivalence of noncommutative models in various (even) dimensions. Physically this map describes condensation of D1-branes.

  69. Ilian T. Iliev, Paul R. Shapiro

    Rotation curves of dark-matter-dominated galaxies measure the mass profiles of galactic halos and thereby test theories of their cosmological origin. While attention has focused lately on the possible discrepancy at small galactocentric radii between observed rotation curves and the singular density profiles predicted by N-body simulations of the Cold Dark M

  70. Michael Gutperle

    In this paper properties of D branes in a nine dimensional asymmetric orbifold are discussed, using a $(-1)^{F_L}σ_{1/2}$ projection, where $F_L$ is the leftmoving space-time fermion number and $σ_{1/2}$ is a freely acting shift of order two. There are two types of non BPS D branes, which are stable at $R>2$ and $R<2$ respectively. At R=2 there is a perturba

  71. Andrew Frey

    We study supersymmetric domain walls in N=1 SU(N) gauge theory with 3 massive adjoint representation chiral multiplets. This theory, known as N=1^*, can be obtained as a massive deformation of N=4 Yang-Mills theory. Following Polchinski and Strassler, we consider the string dual of this theory in terms of spherical 5-branes and construct BPS domain walls int

  72. Paul B. Kantor

    A game in which one player makes unitary transformations of a simple system, and another seeks to confound the resulting state by a randomly chosen action is analyzed carefully. It is shown that the second player can reduce any system to a completely random one by rotation through an angle of 120 degrees, about an axis chosen at random. If, on the other hand

  73. Berthold-Georg Englert, Nasser Metwally

    We distinguish six classes of families of locally equivalent states in a straightforward scheme for classifying all 2-q-bit states; four of the classes consist of two subclasses each. The simple criteria that we stated recently for checking a given state&#39;s positivity and separability are justified, and we discuss some important properties of Lewenstein-S

  74. Diana Monteoliva, Juan Pablo Paz

    We show that for an open quantum system which is classically chaotic (a quartic double well with harmonic driving coupled to a sea of harmonic oscillators) the rate of entropy production has, as a function of time, two relevant regimes: For short times it is proportional to the diffusion coefficient (fixed by the system--environment coupling strength). For l

  75. Pawel Wocjan, Dejan E. Lazic, Thomas Beth

    A conceptually simple method for derivation of lower bounds on the error exponent of specific families of block codes used on classical-quantum channels with arbitrary signal states over a finite Hilbert space is presented. It is shown that families of binary block codes with appropriately rescaled binomial multiplicity enumerators used on binary classical-q

  76. J. Clausen, H. Hansen, L. Knoll, J. Mlynek

    The U(1,1) and U(2) transformations realized by three-mode interaction in the respective parametric approximations are studied in conditional measurement, and the corresponding non-unitary transformation operators are derived. As an application, the preparation of single-mode quantum states using an optical feedback loop is discussed, with special emphasis o

  77. G. S. Agarwal, J. Banerji

    We show how group symmetries can be used to reconstruct quantum states. In our scheme for SU(1,1) states, the input field passes through a non-degenerate parametric amplifier and one measures the probability of finding the output state with a certain number (usually zero) of photons in each mode. The density matrix in the Fock basis is retrieved from the mea

  78. L. -M. Duan, A. Sørensen, J. I. Cirac, P. Zoller

    We propose and analyze a scheme for generating entangled atomic beams out of a Bose-Einstein condensate using spin-exchanging collisions. In particular, we show how to create both atomic squeezed states and entangled states of pairs of atoms.

  79. Samuel J. Lomonaco, jr

    The purpose of these lecture notes is to provide readers, who have some mathematical background but little or no exposure to quantum mechanics and quantum computation, with enough material to begin reading the research literature in quantum computation and quantum information theory. This paper is a written version of the first of eight one hour lectures giv

  80. Alexei Krouglov

    It is shown by the means of Time-Space Model of Wave Propagation the underlying phenomena of the alternating current&#39;s origin in famous Faraday&#39;s experiment.

  81. M. A. Humphrey, D. F. Phillips, R. L. Walsworth

    We use the dressed atom formalism to calculate the frequency shift in a hydrogen maser induced by applied radiation near the Zeeman frequency, and find excellent agreement with a previous calculation made in the bare atom basis. The maser oscillates on the Delta_F = 1, Delta_m_F = 0 hyperfine transition, while the applied field is swept through the F = 1, De

  82. Amichay Vardi, James R. Anglin

    We propose an experiment to measure the slow log(N) convergence to mean-field theory (MFT) around a dynamical instability. Using a density matrix formalism, we derive equations of motion which go beyond MFT and provide accurate predictions for the quantum break-time. The leading quantum corrections appear as decoherence of the reduced single-particle quantum

  83. Debarshi Gangopadhyay, Bichitra Ganguly, Binayak Dutta-Roy

    Positronium (Ps) reaction rates (k) with weak Acceptors (Ac) leading to the formation of Ps-Ac Complexes show several intriguing features: non-monotonic temperature dependence of k (departing from the usual Arrhenius paradigm), considerable variablity of k with respect to different solvents, and anomalies in response to external pressure at ambient temperatu

  84. Giampaolo Co&#39;, Antonio M. Lallena

    A model to calculate nuclear responses considering short-range correlation effects is presented. The model is applied to the study of electromagnetic responses induced by one-body operators. We calculate one- and two-nucleon emission responses and cross sections of the 16O and 40Ca nuclei in the quasi-elastic region, and we compare them with experimental dat

  85. V. Latora, A. Rapisarda

    We present for the first time to the nuclear physics community the Hamiltonian Mean Field (HMF) model. The model can be solved analytically in the canonical ensemble and shows a second-order phase transition in the thermodynamic limit. Numerical microcanonical simulations show interesting features in the out-of-equilibrium regime: in particular the model has

  86. E. Truhlik, F. C. Khanna

    The following items are discussed: 1. The lepton U_l(1) symmetry and its relation to the presence of the neutrino mass term in the Hamiltonian. 2. The possibility of the measurement of the neutrino-deuteron reactions with high energy neutrinos at SNO by using neutrinos from a neutrino factory. 3. The weak axial one-boson exchange currents for the Bethe-Salpe

  87. F. Bonutti, P. Camerini, E. Fragiacomo, N. Grion

    The pion-production reactions $π^+ A \to π^+π^{\pm} A&#39;$ were studied on $^{2}H$, $^{12}C$, $^{40}Ca$, and $^{208}Pb$ nuclei at an incident pion energy of $T_{π^{+}}$=283 MeV. Pions were detected in coincidence using the CHAOS spectrometer. The experimental results are reduced to differential cross sections and compared to both theoretical predictions and

  88. Wei-Xing Zhou, Zun-Hong yu

    Under the formalism of annealed averaging of the partition function, a type of random multifractal measures with their multipliers satisfying exponentially distributed is investigated in detail. Branching emerges in the curve of generalized dimensions, and negative values of generalized dimensions arise. Three equivalent methods of classification of the rand

  89. Mauro Carfora, Annalisa Marzuoli, Paolo Villani

    Deformation theory for 2-dimensional dynamical triangulations with N vertices is discussed by exploiting the geometry of the moduli space of Euclidean polygons. Such an analysis provides an explicit connection among Regge surfaces, dynamical triangulations and the Witten-Kontsevich model. We show that a natural set of Regge measures and a triangulation count

  90. D. Novikov

    An elementary example shows that the number of zeroes of a component of a solution of a system of linear ordinary differential equations cannot be estimated through the norm of coefficients of the system alone.

  91. Jacek Brodzki, Roger Plymen

    Let A(n) be the smooth dual of the p-adic group G=GL(n). We create on A(n) the structure of a complex algebraic variety. There is a morphism of A(n) onto the Bernstein variety Omega G which is injective on each component of A(n). The tempered dual of G is a deformation retract of A(n). The periodic cyclic homology of the Hecke algebra of G is isomorphic to t

  92. William L. Paschke

    We construct irreducible unitary representations of a finitely generated free group which are weakly contained in the left regular representation and in which a given linear combination of the generators has an eigenvalue. When the eigenvalue is specified, we conjecture that there is only one such representation. The representation we have found is described

  93. N. Z. Iorgov, A. U. Klimyk

    We describe properties of the nonstandard q-deformation U&#39;_q(so_n) of the universal enveloping algebra U(so_n) of the Lie algebra so_n which does not coincide with the Drinfeld--Jimbo quantum algebra U_q(so_n). In particular, it is shown that there exists an isomorphism from U&#39;_q(so_n) to U_q(sl_n) and that finite dimensional irreducible representati

  94. Chris Peters

    We give a proof of generalizations of the classical Arakelov inequality valid for the degree $d$ of the relative canoincal bundle of a family of curves of genus $g$ over a complete curve of genus $p$ under the assumption that the monodromy around the singular fibers is unipotent. This relative canonical bundle is the (canonical extension of) the Hodge bundle

  95. Manfredi Maggiore, Kevin Passino

    The problem of controlling surge and stall in jet engine compressors is of fundamental importance in preventing damage and lengthening the life of these components. In this paper, we use the Moore-Greitzer mathematical model to develop an output feedback controller for these two instabilities (only one of the three states is measurable). This problem is part

  96. R. P. Venkataraman

    The necessary and sufficient conditions for differentiability of a function of several real variables stated and proved and its ramifications discussed.

  97. A. Belhaj, M. Hssaini, E. L. Sahraoui, E. H. Saidi

    We develop the noncommutative harmonic space (NHS) analysis to study the problem of solving the non-linear constraint eqs of noncommutative Yang-Mills self-duality in four-dimensions. We show that this space, denoted also as NHS($η,θ$), has two SU(2) isovector deformations $η^{(ij)}$ and $θ^{(ij)}$ parametrising respectively two noncommutative harmonic subsp

  98. Igor Kondrashuk

    D4 N=1 SYM with an arbitrary chiral background superfield as the gauge coupling is considered. The solution to Slavnov-Taylor identities has been given. It has been shown that the solution is unique and allows us to restrict the gauge part of the effective action. Under the effective action in this paper we mean the 1PI diagram generator.

  99. M. N. Chernodub, F. V. Gubarev, M. I. Polikarpov, V. I. Zakharov

    We review recent developments in understanding the physics of the magnetic monopoles in unbroken non-Abelian gauge theories. Since numerical data on the monopoles are accumulated in lattice simulations, the continuum theory is understood as the limiting case of the lattice formulation. In this review, written for a memorial volume dedicated to the memory of

  100. N Dombey, P Kennedy, A Calogeracos

    It is shown that a Dirac particle of mass $m$ and arbitrarily small momentum will tunnel without reflection through a potential barrier $V=U_c(x)$ of finite range provided that the potential well $V=-U_c(x)$ supports a bound state of energy $E=-m.$ This is called a supercritical potential well.