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May 2005 arXiv papers — page 5

Showing 401–500 of 3,731 papers

  1. Elizabeth S. Meckes, Mark W. Meckes

    Motivated by the central limit problem for convex bodies, we study normal approximation of linear functionals of high-dimensional random vectors with various types of symmetries. In particular, we obtain results for distributions which are coordinatewise symmetric, uniform in a regular simplex, or spherically symmetric. Our proofs are based on Stein's me

  2. U. Gavish, B. Yurke, Y. Imry

    General quantum restrictions on the noise performance of linear transistor amplifiers are used to identify the region in parameter space where the quantum-limited performance is achievable and to construct a practical procedure for approaching it experimentally using only the knowledge of directly measurable quantities: the gain, (differential) conductance a

  3. Ilia Binder, Mark Braverman, Michael Yampolsky

    In this paper we consider the computational complexity of uniformizing a domain with a given computable boundary. We give nontrivial upper and lower bounds in two settings: when the approximation of boundary is given either as a list of pixels, or by a Turing Machine.

  4. Jennifer L. Hoffman, Ryan Chornock, Douglas C. Leonard, Alexei V. Filippenko

    We comment on recent spectropolarimetric studies that compare the observed polarization position angles (PAs) of Seyfert 1 galaxies near H alpha with the observed orientations of their radio source axes on the sky. For a Seyfert galaxy in which scattering occurs mainly in an equatorial scattering region, one expects the polarization PA to be parallel to the

  5. Steen Hannestad

    Cosmology at present provides the nominally strongest constraint on the masses of standard model neutrinos. However, this constraint extremely dependent on the nature of the dark energy component of the Universe. When the dark energy equation of state parameter is taken as a free (but constant) parameter, the neutrino mass bound is sum m_nu < 1.48 eV (95% C.

  6. W. Liu, C. M. Ko, L. W. Chen

    Using the $[SU(3)_{\mathrm{L}} \times SU(3)_{\mathrm{R}}]_{\mathrm{global}% }\times [SU(3)_V]_{\mathrm{local}}$ chiral Lagrangian with hidden local symmetry, we evaluate the cross sections for the absorption of eta meson ($% η$) by pion ($π$), rho ($ρ$), omega ($ω$), kaon ($K$), and kaon star ($K^*$) in the tree-level approximation. With empirical masses and

  7. D. Allard, E. Parizot, E. Khan, S. Goriely

    We consider the stochastic propagation of high-energy protons and nuclei in the cosmological microwave and infrared backgrounds, using revised photonuclear cross-sections and following primary and secondary nuclei in the full 2D nuclear chart. We confirm earlier results showing that the high-energy data can be fit with a pure proton extragalactic cosmic ray

  8. A. Ioana, J. Peterson, S. Popa

    We consider amalgamated free product II$_1$ factors $M = M_1 *_B M_2 *_B ...$ and use ``deformation/rigidity&#39;&#39; and ``intertwining&#39;&#39; techniques to prove that any relatively rigid von Neumann subalgebra $Q\subset M$ can be intertwined into one of the $M_i$&#39;s. We apply this to the case $M_i$ are w-rigid II$_1$ factors, with $B$ equal to eith

  9. Patrick McDonald, Hy Trac, Carlo Contaldi

    We present N-body simulation calculations of the dependence of the power spectrum of non-linear cosmological mass density fluctuations on the equation of state of the dark energy, w=p/rho. At fixed linear theory power, increasing w leads to an increase in non-linear power, with the effect increasing with k. By k=10 h/Mpc, a model with w=-0.75 has ~12% more p

  10. James S. Cook

    We develop a gauged Wess-Zumino model in noncommutative Minkowski superspace. This is the natural extension of the work of Carlson and Nazaryan, which extended N=1/2 supersymmetry written over deformed Euclidean superspace to Minkowski superspace. We investigate the interaction of the vector and chiral superfields. Noncommutativity is implemented by replacin

  11. Andreas Ringwald, Thomas J. Weiler, Yvonne Y. Y. Wong

    Resonant annihilation of ultra-high energy cosmic neutrinos (UHECnu) on the cosmic neutrino background (CnuB) into Z bosons--the Z-burst mechanism--and its associated absorption and emission phenomenology provide a unique, albeit indirect, probe of the CnuB in its present state. In this paper, we examine the implications of gravitational clustering of the Cn

  12. Steven J. Bidder, David C. Dunbar, Warren B. Perkins

    We show how Supersymmetric Ward identities can be used to obtain amplitudes involving gluinos or adjoint scalars from purely gluonic amplitudes. We obtain results for all one-loop six-point NMHV amplitudes in $\NeqFour$ Super Yang-Mills theory which involve two gluinos or two scalar particles. More general cases are also discussed.

  13. Nick Evans, Jonathan P. Shock, Tom Waterson

    Many examples of gravitational duals exist of theories that are highly supersymmetric and conformal in the UV yet have the same massless states as {\cal N}=2,1,0 QCD. We discuss such theories with an explicit UV cutoff and propose that, by tuning higher dimension operators at the cutoff by hand, the effects of the extra matter states in the UV may be removed

  14. The BABAR Collaboration, B. Aubert

    We present a first measurement of CP asymmetries in neutral B decays to D+D-, and updated CP asymmetry measurements in decays to D*+D- and D*-D+. We use fully-reconstructed decays collected in a data sample of (232 +- 3) x 10^6 Y(4S) -> BBbar events in the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine the time-dependent asymm

  15. CDF Collaboration, D. Acosta

    We present a measurement of the ratio of top-quark branching fractions R= B(t -> Wb)/B(t -> Wq), where q can be a b, s or a d quark, using lepton-plus-jets and dilepton data sets with integrated luminosity of ~162 pb^{-1} collected with the Collider Detector at Fermilab during Run II of the Tevatron. The measurement is derived from the relative numbers of t-

  16. Daniel Cremades, Fernando Quevedo, Aninda Sinha

    We consider a cosmological scenario within the KKLT framework for moduli stabilization in string theory. The universal open string tachyon of decaying non-BPS D-brane configurations is proposed to drive eternal topological inflation. Flux-induced `warping&#39; can provide the small slow-roll parameters needed for successful inflation. Constraints on the para

  17. Pierre Le Doussal

    We study, using functional renormalization (FRG), two copies of an elastic system pinned by mutually correlated random potentials. Short scale decorrelation depend on a non trivial boundary layer regime with (possibly multiple) chaos exponents. Large scale mutual displacement correlation behave as $|x-x&#39;|^{2 ζ- μ}$, the decorrelation exponent $μ$ proport

  18. Marcelo Gleiser, Joel Thorarinson

    We investigate the properties of $Q$-balls in $d$ spatial dimensions. First, a generalized virial relation for these objects is obtained. We then focus on potentials $V(ϕϕ^{\dagger})= \sum_{n=1}^{3} a_n(ϕϕ^{\dagger})^n$, where $a_n$ is a constant and $n$ is an integer, obtaining variational estimates for their energies for arbitrary charge $Q$. These analyti

  19. Morris Kalka, Giorgio Patrizio

    In this paper we extend our previous work on singularities of Monge-Ampère foliations to the case of pseudoconvex finite type domains. We are able to answer the questin of Burns on homogeneous polynomials whose logarithm satisfies the complex Monge-Ampère equation completely in dimension 2 . We are also able to generalize the work of P.M. Wong in dimension 2

  20. H L Gomez, L Dunne, S Eales, E Gomez

    It has been suggested by Dwek (2004) that iron needles could explain the submillimetre emission from the Cas A supernova remnant (SNR) with only a very small total mass. We investigate whether a similar model holds for the Kepler supernova remnant, and find that its emission could indeed be explained by a dust mass of less than 10^-2 M_sun dependent on the a

  21. B. E. Cox, A. De Roeck, V. A. Khoze, T. Pierzchala

    We present a detailed study of the central exclusive production of the Standard Model Higgs Boson in the WW decay channel at the LHC. We include estimates of the experimental acceptance, including that of the proposed proton tagging detectors at 220m and 420m around either ATLAS and / or CMS, and the level 1 trigger acceptances. We give first estimates of th

  22. Arnaud Buhot

    The Rubinstein-Duke or repton model is one of the simplest lattice model of reptation for the diffusion of a polymer in a gel or a melt. Recently, a slightly modified model with hardcore interactions between the reptons has been introduced. The curvilinear diffusion coefficients of both models are exactly determined for all chain lengths. The case of periodi

  23. S. Roemer, D. Duerr, T. Moser

    We study the asymptotic behavior of Bohmian trajectories in a scattering situation with short range potential and for wave functions with a scattering and a bound part. It is shown that the set of possible trajectories splits into trajectories whose long time behavior is governed by the scattering part of the wave function (scattering trajectories) and traje

  24. I. Jack, D. R. T. Jones, A. F. Kord

    We present the full two-loop beta-functions for the MSSM including R-parity violating couplings. We analyse the effect of two-loop running on the bounds on R-parity violating couplings, on the nature of the LSP and on the stop masses.

  25. Marco Baldi, Fabio Finelli, Sabino Matarrese

    Inflation may have been driven by a component which violated the Null-Energy Condition, thereby leading to {\it super inflation}. We provide the formalism to study cosmological perturbations when such a component is described by a scalar field with arbitrary Lagrangian. Since the background curvature grows with time, gravitational waves always have a blue sp

  26. Sanshui Xiao, Min Qiu

    Optical microcavities based on zero-group-velocity surface modes in photonic crystal slabs are studied. It is shown that high quality factors can be easily obtained for such microcavities in photonic crystal slabs. With increasing of the cavity length, the quality factor is gradually enhanced and the resonant frequency converges to that of the zero-group-vel

  27. Emilio De Santis, Carlo Marinelli

    We introduce and study a class of infinite-horizon non-zero-sum non-cooperative stochastic games with infinitely many interacting agents using ideas of statistical mechanics. First we show, in the general case of asymmetric interactions, the existence of a strategy that allows any player to eliminate losses after a finite random time. In the special case of

  28. Yu. M. Bystritskiy, G. V. Fedotovich, F. V. Ignatov, E. A. Kuraev

    The processes of muons (tau) and charged pions pairs production at electron-positron annihilation with first order radiative corrections are considered. The calculation results are presented assuming the energies of final particles (cms implied) to be not far significantly from threshold production. The invariant mass distributions for the muon (tau) and pio

  29. P. Singha Deo, P. Koskinen, M. Manninen

    Coupled systems in mesoscopic regime are of interest as charge fluctuation between the sub-systems will depend on electron-electron interactions and will play a dominant role in determining their thermodynamic properties. We study some simple systems like a stub or a bubble strongly coupled to a ring. We show that for strong electron-electron interaction, th

  30. Matthias Franz, Volker Puppe

    Using methods applied by Atiyah in equivariant K-theory, Bredon obtained exact sequences for the relative cohomologies (with rational coefficients) of the equivariant skeletons of (sufficiently nice) T-spaces, T=(S^1)^n, with free equivariant cohomology over the cohomology of BT. Here we characterise those finite T-CW complexes with connected isotropy groups

  31. Belle Collaboration, I. Bizjak

    We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V_ub|, based on 253 fb^-1 of data collected by the Belle detector at the KEKB e^+e^- asymmetric collider. Events are tagged by fully reconstructing one of the B mesons, produced in pairs from Upsilon(4S). The signal for b->u semileptonic decay is distinguished from the b->c background

  32. Claudia Fritz, Joe Wolfe

    In a simple model, the reed of the clarinet is mechanically loaded by the series combination of the acoustical impedances of the instrument itself and of the player&#39;s vocal tract. Here we measure the complex impedance spectrum of players&#39; tracts using an impedance head adapted to fit inside a clarinet mouthpiece. A direct current shunt with high acou

  33. G. Falqui

    We consider a generalization of the Camassa Holm (CH) equation with two dependent variables, called CH2, introduced by Liu and Zhang. We briefly provide an alternative derivation of it based on the theory of Hamiltonian structures on (the dual of) a Lie Algebra. The Lie Algebra here involved is the same algebra underlying the NLS hierarchy. We study the stru

  34. Junji Hisano, Mitsuru Kakizaki, Minoru Nagai

    We point out that the null results of the hadronic electric dipole moment (EDM) searches constrain orbifold grand unified theories (GUTs), where the GUT symmetry and supersymmetry (SUSY) are both broken by boundary conditions in extra dimensions and it leads to rich fermion and sfermion flavor structures. A marginal chromoelectric dipole moment (CEDM) of the

  35. Jayanth R. Banavar, Marek Cieplak, Alessandro Flammini, Trinh X. Hoang

    The functionality of proteins is related to their structure in the native state. Protein structures are made up of emergent building blocks of helices and almost planar sheets. A simple coarse-grained geometrical model of a flexible tube barely subject to compaction provides a unified framework for understanding the common character of globular proteins.We a

  36. A. Hillenbrand, M. Hartig

    Hadron multiplicities of $\pim$, $\pip$, $\km$ and $\kp$ have been measured in the deep-inelastic scattering of 27.5 GeV positrons off a hydrogen target. The data used in this analysis have been collected during the 2000 HERA running period. The multiplicities were obtained for 0.15$< z <$0.9 for $<Q^2>$ = 2.5 GeV$^2$.

  37. C. Garcia-Recio, J. Nieves, L. L. Salcedo

    A consistent SU(6) extension of the Weinberg-Tomozawa meson-baryon chiral Lagrangian is constructed which incorporates vector meson and baryon decuplet degrees of freedom. The corresponding Bethe-Salpeter approximation predicts the existence of an isoscalar spin-parity ${3/2}^-$ $K^*N$ bound state (strangeness +1) with a mass around 1.7--1.8$ $GeV. It is the

  38. Maurice A. De Gosson

    A classical theorem of Stone and von Neumann says that the Schrödinger representation is, up to unitary equivalences, the only irreducible representation of the Heisenberg group on the Hilbert space of square-integrable functions on configuration space. Using the Wigner-Moyal transform we construct an irreducible representation of the Heisenberg group on a c

  39. Koji Azuma, Junichi Shimamura, Masato Koashi, Nobuyuki Imoto

    We consider probabilistic cloning of a state chosen from a mutually nonorthogonal set of pure states, with the help of a party holding supplementary information in the form of pure states. When the number of states is 2, we show that the best efficiency of producing m copies is always achieved by a two-step protocol in which the helping party first attempts

  40. D. A. Head, A. J. Levine, F. C. MacKintosh

    Previous research on semiflexible polymers including cytoskeletal networks in cells has suggested the existence of distinct regimes of elastic response, in which the strain field is either uniform (affine) or non-uniform (non-affine) under external stress. Associated with these regimes, it has been further suggested that a new fundamental length scale emerge

  41. A. L. Kataev

    The basis of renormalon calculus is briefly discussed. The method is applied to study QCD predictions for three sum rules of deep-inelastic scattering, namely for the Gross-Llewellyn Smith, Bjorken polarized and unpolarized sum rules. It is shown that the renormalon structures of theses sum rules are closely related. These properties are giving us the hint t

  42. Tomo Munehisa, Yasuko Munehisa

    We describe a further development of the stochastic state selection method, a new Monte Carlo method we have proposed recently to make numerical calculations in large quantum spin systems. Making recursive use of the stochastic state selection technique in the Lanczos approach, we estimate the ground state energy of the spin-1/2 quantum Heisenberg antiferrom

  43. M. Shao, O. Barannikova, X. Dong, Y. Fisyak

    Particle identification (PID) capabilities are studied by using the Time Projection Chamber (TPC) and a Time-Of-Flight (TOF) detector together at STAR. The identification capability of charged hadrons is greatly extended compared with that achieved by TPC and TOF separately. Particle spectra from p+p, d+Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV and Au+Au c

  44. Celine Cattoen, Tristan Faber, Matt Visser

    One of the very small number of serious alternatives to the usual concept of an astrophysical black hole is the &#34;gravastar&#34; model developed by Mazur and Mottola; and a related phase-transition model due to Laughlin et al. We consider a generalized class of similar models that exhibit continuous pressure -- without the presence of infinitesimally thin

  45. John Hegseth

    Many quantization schemes rely on analogs of classical mechanics where the connections with classical mechanics are indirect. In this work I propose a new and direct connection between classical mechanics and quantum mechanics where the quantum mechanical propagator is derived from a variational principle. I identify this variational principle as a generaliz

  46. Animesh Datta, Steven T. Flammia, Carlton M. Caves

    The &#34;Power of One Qubit&#34; refers to a computational model that has access to only one pure bit of quantum information, along with n qubits in the totally mixed state. This model, though not as powerful as a pure-state quantum computer, is capable of performing some computational tasks exponentially faster than any known classical algorithm. One such t

  47. Jaromir Fiurasek, Radim Filip, Nicolas J. Cerf

    We investigate the universal asymmetric cloning of states in a Hilbert space of arbitrary dimension. We derive the class of optimal and fully asymmetric 1->3 cloners, which produce three copies, each having a different fidelity. A simple parametric expression for the maximum achievable cloning fidelity triplets is then provided. As a side-product, we also pr

  48. J. Fan, A. Migdall, L. J. Wang

    We report efficient generation of correlated photon pairs through degenerate four-wave mixing in microstructure fibers. With 735.7 nm pump pulses producing conjugate signal (688.5 nm) and idler (789.8 nm) photons in a 1.8 m microstructure fiber, we detect photon pairs at a rate of 37.6 kHz with a coincidence/accidental contrast of 10:1 with a full-width-at-h

  49. J. Klepp, S. Sponar, Y. Hasegawa, E. Jericha

    We have measured the Pancharatnam relative phase for spin-1/2 states. In a neutron polarimetry experiment the minima and maxima of intensity modulations, giving the Pancharatnam phase, were determined. We have also considered general SU(2) evolution for mixed states. The results are in good agreement with theory.

  50. P J Lee, K-A Brickman, L Deslauriers, P C Haljan

    There are several known schemes for entangling trapped ion quantum bits for large-scale quantum computation. Most are based on an interaction between the ions and external optical fields, coupling internal qubit states of trapped-ions to their Coulomb-coupled motion. In this paper, we examine the sensitivity of these motional gate schemes to phase fluctuatio

  51. Adam Brazier, Vladimir Buzek, Peter L. Knight

    We examine the execution of general U(1) transformations on programmable quantum processors. We show that, with only the minimal assumption of availability of copies of the one-qubit program state, that the apparent advantage of existing schemes proposed by G.Vidal it et al. [Phys. Rev. Lett. 88, 047905 (2002)] and M.Hillery et al. [Phys. Rev. A. 65, 022301

  52. Benny Chor, Michael D. Hendy, Sagi Snir

    Complex systems of polynomial equations have to be set up and solved algebraically in order to obtain analytic solutions for maximum likelihood on phylogenetic trees. This has restricted the types of systems previously resolved to the simplest models - three and four taxa under a molecular clock, with just two state characters. In this work we give, for the

  53. Matthieu Delescluse, Christophe Pouzat

    We demonstrate the efficacy of a new spike-sorting method based on a Markov Chain Monte Carlo (MCMC) algorithm by applying it to real data recorded from Purkinje cells (PCs) in young rat cerebellar slices. This algorithm is unique in its capability to estimate and make use of the firing statistics as well as the spike amplitude dynamics of the recorded neuro

  54. Viviane M. de Oliveira, M. A. F. Gomes, I. R. Tsang

    Here we describe how some important scaling laws observed in the distribution of languages on Earth can emerge from a simple computer simulation. The proposed language dynamics includes processes of selective geographic colonization, linguistic anomalous diffusion and mutation, and interaction among populations that occupy different regions. It is found that

  55. Vadim A. Markel, John C. Schotland

    We describe a new data collection scheme for optical diffusion tomography in which plane wave illumination is combined with multiple projections in the slab imaging geometry. Multiple projection measurements are performed by rotating the slab around the sample. The advantage of the proposed method is that the measured data can be much more easily fitted into

  56. R. C. Gupta

    It is well known that magnetic force between two current carrying conductors is a relativistic manifestation of net electrostatic force between relatively moving electrons & protons of the two wires. On similar grounds but with more accurate considerations i.e., of second order relativistic considerations, it is shown here that gravitational-force between tw

  57. Der Chyan Lin, Asif Sharif, Hon Kwan

    The scaling property of the brain dynamics is studied based on the zero-crossing of the local electroencephalographic (EEG) recording taken from healthy young adults in eyes closed and eyes open. Evidence of coupling between the EEG fractal dynamics and the $α$ rhythm is presented. An organization principle that governs this coupling relationship is proposed

  58. Stephen R. Cotanch, Robert A. Williams

    Using vector meson dominance (VMD), tensor glueball photoproduction cross sections, asymmetries and widths are calculated. The predicted hadronic VV&#39; decays are comparable for different vector meson (V = rho, omega and phi) channels with the omega phi width the largest but the radiative omega gamma and phi gamma decays are suppressed relative to rho gamm

  59. A. F. Lisetskiy, V. V. Flambaum, V. G. Zelevinsky

    Nuclear forces violating parity and time reversal invariance P,T-odd produce P,T-odd nuclear moments, for example, the nuclear Schiff moment. In turn, this moment can induce the electric dipole moment (EDM) in the atom. The contribution to the Schiff moment from the soft collective quadrupole and octupole vibrations in spherical nuclei is calculated in the f

  60. J. Golak, R. Skibinski, H. Witala, W. Gloeckle

    A big spectrum of processes induced by real and virtual photons on the 3He and 3H nuclei is theoretically investigated through many examples based on nonrelativistic Faddeev calculations for bound and continuum states. The modern nucleon-nucleon potential AV18 together with the three-nucleon force UrbanaIX is used. The single nucleon current is augmented by

  61. B. K. Agrawal, S. Shlomo, V. Kim Au

    We implement for the first time the simulated annealing method (SAM) to the problem of searching for the global minimum in the hyper-surface of the chi-square function which depends on the values of the parameters of a Skyrme type effective nucleon-nucleon interaction. We undertake a realistic case of fitting the values of the Skyrme parameters to an extensi

  62. Tomoyuki Maruyama, Satoshi Chiba

    We define the new description of the electromagnetic current to hold the current conservation in the momentum-dependent Dirac fields from the Ward Takahashi identity. To describe the momentum-dependence we solve the relativistic Hartree-Fock approximation by using the one-pion exchange. In addition we discuss on contribution from the one-pion exchange curren

  63. Jani Lukkarinen, Herbert Spohn

    We study crystal dynamics in the harmonic approximation. The atomic masses are weakly disordered, in the sense that their deviation from uniformity is of order epsilon^(1/2). The dispersion relation is assumed to be a Morse function and to suppress crossed recollisions. We then prove that in the limit epsilon to 0 the disorder averaged Wigner function on the

  64. Nantel Bergeron, Yun Gao, Naihong Hu

    We find the defining structures of two-parameter quantum groups $U_{r,s}(\frak g)$ corresponding to the orthogonal and the symplectic Lie algebras, which are realized as Drinfel&#39;d doubles. We further investigate the environment conditions upon which the Lusztig&#39;s symmetries exist between $(U_{r,s}(\frak g), < ,>)$ and its associated object $(U_{s^{-1

  65. Nantel Bergeron, Christophe Hohlweg

    For $G$ a finite abelian group, we study the properties of general equivalence relations on $G_n=G^n\rtimes \SG_n$, the wreath product of $G$ with the symmetric group $\SG_n$, also known as the $G$-coloured symmetric group. We show that under certain conditions, some equivalence relations give rise to subalgebras of $\k G_n$ as well as graded connected Hopf

  66. Dongseok Kim, Jaeun Lee

    Several natural partial orders on integral partitions, such as the embeddability, the stable embeddability, the bulk embeddability and the supermajorization, raise in the quantum computation, bin-packing and matrix analysis. We find the implications between these partial orders. For integral partitions whose entries are all powers of a fixed number $p$, we s

  67. Michael Blank, Leonid Bunimovich

    We show that under certain simple assumptions on the topology (structure) of networks of strongly interacting chaotic elements a phenomenon of long range action takes place, namely that the asymptotic (as time goes to infinity) dynamics of an arbitrary large network is completely determined by its boundary conditions. This phenomenon takes place under very m

  68. Lancelot F. James

    Suppose that P_θ(g) is a linear functional of a Dirichlet process with shape θH, where θ>0 is the total mass and H is a fixed probability measure. This paper describes how one can use the well-known Bayesian prior to posterior analysis of the Dirichlet process, and a posterior calculus for Gamma processes to ascertain properties of linear functionals of Diri

  69. James O. Berger, William Strawderman, Dejun Tang

    Hierarchical modeling is wonderful and here to stay, but hyperparameter priors are often chosen in a casual fashion. Unfortunately, as the number of hyperparameters grows, the effects of casual choices can multiply, leading to considerably inferior performance. As an extreme, but not uncommon, example use of the wrong hyperparameter priors can even lead to i

  70. Donglin Zeng

    In many public health problems, an important goal is to identify the effect of some treatment/intervention on the risk of failure for the whole population. A marginal proportional hazards regression model is often used to analyze such an effect. When dependent censoring is explained by many auxiliary covariates, we utilize two working models to condense high

  71. Rui Paulo

    Motivated by the statistical evaluation of complex computer models, we deal with the issue of objective prior specification for the parameters of Gaussian processes. In particular, we derive the Jeffreys-rule, independence Jeffreys and reference priors for this situation, and prove that the resulting posterior distributions are proper under a quite general s

  72. Pei-Sheng Lin, Murray K. Clayton

    The goal of this paper is to describe the application of quasi-likelihood estimating equations for spatially correlated binary data. In this paper, a logistic function is used to model the marginal probability of binary responses in terms of parameters of interest. With mild assumptions on the correlations, the Leonov-Shiryaev formula combined with a compari

  73. Dominique Cerveau

    We study complex vector fields with straight lines trajectories. Some applications to rational solutions of ikonals equations are given

  74. R. M. Balan, I. Schiopu-Kratina

    We consider the marginal models of Liang and Zeger [Biometrika 73 (1986) 13-22] for the analysis of longitudinal data and we develop a theory of statistical inference for such models. We prove the existence, weak consistency and asymptotic normality of a sequence of estimators defined as roots of pseudo-likelihood equations.

  75. Xiaogang Wang, James V. Zidek

    The (relevance) weighted likelihood was introduced to formally embrace a variety of statistical procedures that trade bias for precision. Unlike its classical counterpart, the weighted likelihood combines all relevant information while inheriting many of its desirable features including good asymptotic properties. However, in order to be effective, the weigh

  76. P. Gilkey, S. Nikcevic

    We study the isometry groups and Killing vector fields of a family of pseudo-Riemannian metrics on Euclidean space which have neutral signature (3+2p,3+2p). All are p+2 curvature homogeneous, all have vanishing Weyl scalar invariants, all are geodesically complete, and all are 0-curvature modeled on an indecomposible symmetric space. Some of these manifolds

  77. Vyacheslav M. Abramov

    This paper provides the asymptotic analysis of the loss probability in the $GI/M/1/n$ queueing system as $n$ increases to infinity. The approach of this paper is alternative to that of the recent papers of Choi and Kim [2000] and Choi et al [2000] and based on application of modern Tauberian theorems with remainder. This enables us to simplify the proofs of

  78. Vyacheslav M. Abramov

    The goal of the paper is to study asymptotic behavior of the number of lost messages. Long messages are assumed to be divided into a random number of packets which are transmitted independently of one another. An error in transmission of a packet results in the loss of the entire message. Messages arrive to the $M/GI/1$ finite buffer model and can be lost in

  79. V. V. Peller

    In this paper we consider the problem of the existence of higher derivatives of the function $t\mapsto\f(A+tK)$, where $\f$ is a function on the real line, $A$ is a self-adjoint operator, and $K$ is a bounded self-adjoint operator. We improve earlier results by Sten&#39;kin. In order to do this, we give a new approach to multiple operator integrals. This app

  80. Thierry Barbot

    Let $Γ$ be a surface group of higher genus. Let $ρ\_0: Γ\to {PGL}(V)$ be a discrete faithful representation with image contained in the natural embedding of ${SL}(2, {\mathbb R})$ in ${PGL}(3, {\mathbb R})$ as a group preserving a point and a disjoint projective line in the projective plane. We prove that such a representation is $(G,Y)$-Anosov (following th

  81. Bing-Long Chen, Xi-Ping Zhu

    The Ricci flow is an evolution system on metrics. For a given metric as initial data, its local existence and uniqueness on compact manifolds was first established by Hamilton \cite{Ha1}. Later on, De Turck \cite{De} gave a simplified proof. In the later of 80&#39;s, Shi \cite{Sh1} generalized the local existence result to complete noncompact manifolds. Howe

  82. Xiuxiong Chen, Peng Lu, Gang Tian

    In this note we clarify that the Rcci flow can be used to give an independent proof of the uniformization theorem of Riemann surfaces.

  83. Nathanaël Enriquez, Christophe Sabot

    This paper states a law of large numbers for a random walk in a random iid environment on ${\mathbb Z}^d$, where the environment follows some Dirichlet distribution. Moreover, we give explicit bounds for the asymptotic velocity of the process and also an asymptotic expansion of this velocity at low disorder.

  84. L. Lapointe, J. Morse

    We prove that structure constants related to Hecke algebras at roots of unity are special cases of k-Littlewood-Richardson coefficients associated to a product of k-Schur functions. As a consequence, both the 3-point Gromov-Witten invariants appearing in the quantum cohomology of the Grassmannian, and the fusion coefficients for the WZW conformal field theor

  85. Richard P. Stanley

    We are given k points (events) in (n+1)-dimensional Minkowski space. Using the theory of hyperplane arrangments and chromatic polynomials, we obtain information the number of different orders in which the events can occur in different reference frames if the events are sufficiently generic. We consider the question of what sets of orderings of the points are

  86. Mikhail Karasev

    We observe ``quantum&#39;&#39; properties of resonance equilibrium points and resonance univariant submanifolds in the phase space. Resonances between Birkhoff or Floquet--Lyapunov frequencies generate quantum algebras with polynomial commutation relations. Irreducible representations and coherent states of these algebras correspond to certain quantum nano-s

  87. Ludwik Dabrowski, Giovanni Landi, Mario Paschke, Andrzej Sitarz

    We propose a slight modification of the properties of a spectral geometry a la Connes, which allows for some of the algebraic relations to be satisfied only modulo compact operators. On the equatorial Podles sphere we construct suq2-equivariant Dirac operator and real structure which satisfy these modified properties.

  88. Jan Obloj

    We investigate the optimal stopping problems involving the supremum of a diffusion. The starting point is the link between works of Peskir and Meilijson, which we describe in a unified manner. The description developped follows mainly the work of Peskir and relies on the maximality principle which links the existence and form of the solution to an optimal st

  89. I. Jack, D. R. T. Jones, L. A. Worthy

    We investigate the one-loop renormalisability of a general N=1/2 supersymmetric gauge theory coupled to chiral matter, and show the existence of an N=1/2 supersymmetric SU(N)xU(1) theory which is renormalisable at one loop.

  90. Qi-jun Yin, Jian-Zu Zhang

    In two-dimensional space a subtle point that for the case of both space-space and momentum-momentum noncommuting, different from the case of only space-space noncommuting, the deformed Heisenberg-Weyl algebra in noncommutative space is not completely equivalent to the undeformed Heisenberg-Weyl algebra in commutative space is clarified. It follows that there

  91. Richard J. Szabo

    Prepared for the Quantum Field Theory section of the Encyclopedia of Mathematical Physics, Elsevier, 2006. A brief introduction to the methodology and techniques of perturbative relativistic quantum field theory is presented.

  92. David Diego, Gero von Gersdorff, Mariano Quiros

    Hypermultiplets are considered in the five-dimensional interval where all fields are continuous and the boundary conditions are dynamically obtained from the action principle. The orbifold boundary conditions are obtained as particular cases. We can interpret the Scherk-Schwarz supersymmetry breaking as a misalignment of boundary conditions while a new sourc

  93. Sebastian Jager

    We present a quantitative analysis of the flavor physics of a SUSY SO(10) model proposed by Chang, Masiero, and Murayama, linking b -> s transitions to the large observed atmospheric neutrino mixing. We consider B_s-B_s-bar mixing and tau -> mu gamma and discuss their correlation paying careful attention to their different dependences on model parameters. Ou

  94. Anne-Christine Davis, Konstantinos Dimopoulos

    Cosmic superstrings are produced at the end of brane inflation. Their properties are similar to cosmic strings arising in grand unified theories. Like cosmic strings they can give rise to a primordial magnetic field, as a result of vortical motions stirred in the ionised plasma by the gravitational pull of moving string segments. The resulting magnetic field

  95. Kingman Cheung, Yueh-Feng Liu

    We perform a global analysis of the tree-level open-string amplitudes in the limit $s << M_S^2$ . Based on the present data from the Tevatron, HERA, and LEP~2, we set a lower limit on the string scale $M_S >= 0.69 - 1.96$ TeV at 95 % confidence level for the Chan-Paton factors $|T|=0 - 4$. We also estimate the expected sensitivities at the LHC, which can be

  96. B. Borasoy, R. Nissler, W. Weise

    The anti-kaon nucleon system close to threshold is analyzed in view of the new accurate DEAR kaonic hydrogen data. The calculations are performed using chiral SU(3) effective field theory in combination with non-perturbative schemes based on coupled channels. Several variants of such approaches are compared with experimental data and the differences in the r

  97. R. Peschanski

    We derive parametric travelling-wave solutions of non-linear QCD equations. They describe the evolution towards saturation in the geometric scaling region. The method, based on an expansion in the inverse of the wave velocity, leads to a solvable hierarchy of differential equations. A universal parametric form of travelling waves emerges from the first two o

  98. Y. Hatta, E. Iancu, L. McLerran, A. Stasto

    We show that the recently developed Hamiltonian theory for high energy evolution in QCD in the dilute regime and in the presence of Bremsstrahlung is consistent with the color dipole picture in the limit where the number of colors N_c is large. The color dipoles are quark-antiquark pairs which can radiate arbitrarily many soft gluons, and the evolution consi

  99. F. Cossutti

    The systematic uncertainty on the W mass and width measurement resulting from the imperfect knowledge of electroweak radiative corrections is discussed. The intrinsic uncertainty in the 4-f generator used by the DELPHI Collaboration is studied following the guidelines of the authors of YFSWW, on which its radiative corrections part is based. The full DELPHI

  100. Tomas Brauner, Jiri Hosek

    We consider a model with global Abelian chiral symmetry of two massless fermion fields interacting with a complex massive scalar field. We argue that the Schwinger-Dyson equations for the fermion and boson propagators admit ultraviolet-finite chiral-symmetry-breaking solutions provided the Yukawa couplings are large enough. The fermions acquire masses and th