Research archive

arXiv papers from April 2007

The most recent 100 records published that month. Open any paper for its original abstract, citation metadata, related research, and reading tools.

  1. Savas Dayanik, Christian Goulding, H. Vincent Poor

    This paper examines the joint problem of detection and identification of a sudden and unobservable change in the probability distribution function (pdf) of a sequence of independent and identically distributed (i.i.d.) random variables to one of finitely many alternative pdf's. The objective is quick detection of the change and accurate inference of the ensu

  2. L. Dawson, H. McGahagan, G. Ponce

    We construct a local in time, exponentially decaying solution of the one-dimensional variable coefficient Schrodinger equation by solving a nonstandard boundary value problem. A main ingredient in the proof is a new commutator estimate involving the projections P+ and P- onto the positive and negative frequencies.

  3. Vadim Astakhov

    Resent works of Hawking and Susskind suggested that information is conserved in the universe. We extend this thesis and propose that dynamics of information - computations can conserve in Anti-de-Sitter cosmological model. Information geometry formalism is proposed to analyze information in dynamical systems. We consider entropy flow as a geometrical flow on

  4. R. Saniz, B. Barbiellini, P. M. Platzman, A. J. Freeman

    The possibility of having positronium (Ps) physisorbed at a material surface is of great fundamental interest, since it can lead to new insight regarding quantum sticking and is a necessary first step to try to obtain a Ps$_2$ molecule on a material host. Some experiments in the past have produced evidence for physisorbed Ps on a quartz surface, but firm the

  5. C. Brenner Mariotto, V. P. Goncalves

    In this paper we estimate the influence of nonlinear gluon evolution in the production of prompt photons at the LHC pp collider. We assume the validity of collinear factorization and consider the EHKQS parton distributions, which are solutions of the GLR-MQ evolution equations and describe quite well the DESY $ep$ HERA data, as input in our calculations. We

  6. Michael Ramsey-Musolf, Shufang Su, Sean Tulin

    We compute supersymmetric contributions to pion leptonic (\pi_{l2}) decays in the Minimal Supersymmetric Standard Model (MSSM). When R-parity is conserved, the largest contributions to the ratio R_{e/\mu} = \Gamma[ \pi^+ \to e^+ \nu_e(\gamma)]/\Gamma[ \pi^+ \to \mu^+ \nu_\mu(\gamma)] arise from one-loop (V-A)x(V-A) corrections. These contributions can be pot

  7. Andrés Navas

    We show that bi-Lipschitz conjugacies between non singular one dimensional systems are forced to be smooth, at least in the minimal (and ergodic) case. This is however far from being true in the non minimal case. These results clarify a classical work by Ghys and Tsuboi.

  8. Nikos Frantzikinakis, Randall McCutcheon

    We survey the impact of the Poincar\'e recurrence principle in ergodic theory, especially as pertains to the field of ergodic Ramsey theory.

  9. Sergiu I. Vacaru

    We elaborate an unified geometric approach to classical mechanics, Riemann-Finsler spaces and gravity theories on Lie algebroids provided with nonlinear connection (N-connection) structure. There are investigated the conditions when the fundamental geometric objects like the anchor, metric and linear connection, almost sympletic and related almost complex st

  10. Frederick K. Lamb

    Quasi-periodic oscillations (QPOs) have been discovered in the X-ray emission of many neutron stars and black holes. The QPOs with frequencies greater than about 300 Hz are thought to be produced near the surfaces of neutron stars and the event horizons of black holes. I first summarize some of the most important properties of the QPOs seen in neutron star a

  11. Esteban Guevara

    By analyzing the relationships between a socioeconomical system modeled through evolutionary game theory and a physical system modeled through quantum mechanics we show how although both systems are described through two theories apparently different both are analogous and thus exactly equivalents. The extensions of quantum mechanics to statistical physics a

  12. Eric D'Hoker, John Estes, Michael Gutperle

    Regularity and topology conditions are imposed on the exact Type IIB solutions on $AdS_4 \times S^2 \times S^2 \times \Sigma $ with 16 supersymmetries, which were derived in a companion paper. We construct an infinite class of regular solutions with varying dilaton, and non-zero 3-form fluxes. Our solutions may be viewed as the fully back-reacted geometries

  13. A. Hamma, W. Zhang, S. Haas, D. A. Lidar

    We present a numerical study of a quantum phase transition from a spin-polarized to a topologically ordered phase in a system of spin-1/2 particles on a torus. We demonstrate that this non-symmetry-breaking topological quantum phase transition (TOQPT) is of second order. The transition is analyzed via the ground state energy and fidelity, block entanglement,

  14. L. Ravagli, R. Rapp

    We employ the Boltzmann equation for describing hadron production from a quark-gluon plasma (QGP) in ultrarelativistic heavy-ion collisions. We propose resonance formation in quark-antiquark scattering as the dominant meson-production channel, which, in particular, ensures that energy is conserved in the recombination process. This, in turn, facilitates a mo

  15. Jenny E. Greene, Luis C. Ho

    We present the first measurement of the black hole (BH) mass function for broad-line active galaxies in the local Universe. Using the ~9000 broad-line active galaxies from the Fourth Data Release of the Sloan Digital Sky Survey, we construct a broad-line luminosity function that agrees very well with the local soft X-ray luminosity function. Using standard v

  16. Z. F. Wang, Huaixiu Zheng, Q. W. Shi, Jie Chen

    Stimulated by recent advances in isolating graphene, we discovered that quantum dot can be trapped in Z-shaped graphene nanoribbon junciton. The topological structure of the junction can confine electronic states completely. By varying junction length, we can alter the spatial confinement and the number of discrete levels within the junction. In addition, qu

  17. Ian Ellwood

    We argue that the rolling-tachyon solution in cubic OSFT proceeds at late times to precisely the analytic tachyon-vacuum solution constructed by Schnabl. In addition, we demonstrate the relationship between the rolling-tachyon solution and the standard BCFT description by showing that there is a finite gauge transformation which relates the two.

  18. A. N. Petrov

    The field-theoretical approach is reviewed. Perturbations in general relativity as well as in an arbitrary $D$-dimensional metric theory are studied on a background, which is a solution (arbitrary) of the theory. Lagrangian for perturbations is defined, and field equations for perturbations are derived from the variational principle. These equations are exac

  19. J. B. Marston, E. Conover, Tapio Schneider

    Low-order equal-time statistics of a barotropic flow on a rotating sphere are investigated. The flow is driven by linear relaxation toward an unstable zonal jet. For relatively short relaxation times, the flow is dominated by critical-layer waves. For sufficiently long relaxation times, the flow is turbulent. Statistics obtained from a second-order cumulant

  20. M. Chu, R. E. Rudd, M. P. Blencowe

    Dissipation in the flexural dynamics of doubly clamped nanomechanical bar resonators is investigated using molecular dynamics simulation. The dependence of the quality factor Q on temperature and the size of the resonator is calculated from direct simulation of the oscillation of a series of Si <001> bars with bare {100} dimerized surfaces. The bar widths ra

  21. E. -M. Ilgenfritz, K. Koller, Y. Koma, G. Schierholz

    Overlap fermions have an exact chiral symmetry on the lattice and are thus an appropriate tool for investigating the chiral and topological structure of the QCD vacuum. We study various chiral and topological aspects of quenched gauge field configurations. This includes the localization and chiral properties of the eigenmodes, the local structure of the ultr

  22. D. Horns, A. I. D. Hoffmann, A. Santangelo, F. A. Aharonian

    (abridged) The first unidentified very high energy gamma ray source (TeV J2032+4130) in the Cygnus region has been the subject of intensive search for a counterpart source at other wavelengths. A deep ($\approx 50$ ksec) exposure of TeV J2032+4130 with \textit{XMM-Newton} has been obtained. The contribution of point sources to the observed X-ray emission fro

  23. Elena Gallo

    With their relatively fast variability time-scales, Galactic X-ray binaries provide an excellent laboratory to explore the physics of accretion and related phenomena, most notably outflows, over different regimes. After comparing the phenomenology of jets in black hole X-ray binary systems to that of neutron stars, here I discuss the role of the jet at very

  24. Mikami Hirasawa, Kunio Murasugi, Daniel S. Silver

    Necessary and sufficient conditions are given for a satellite knot to be fibered. Any knot $\tilde k$ embeds in an unknotted solid torus $\tilde V$ with arbitrary winding number in such a way that no satellite knot with pattern $(\tilde V, \tilde k)$ is fibered. In particular, there exist nonfibered satellite knots with fibered pattern and companion knots an

  25. S. N. Dorogovtsev, A. V. Goltsev, J. F. F. Mendes

    The combination of the compactness of networks, featuring small diameters, and their complex architectures results in a variety of critical effects dramatically different from those in cooperative systems on lattices. In the last few years, researchers have made important steps toward understanding the qualitatively new critical phenomena in complex networks

  26. Jean-Pierre Derendinger, P. Marios Petropoulos, Nikolaos Prezas

    We study the class of four-dimensional N=4 supergravities obtained by gauging the axionic shift and axionic rescaling symmetries. We formulate these theories using the machinery of embedding tensors, characterize the full gauge algebras and discuss several specific features of this family of gauged supergravities. We exhibit in particular a generalized duali

  27. Aravind Natarajan, Pierre Sikivie

    Caustic rings of dark matter were predicted to exist in the plane of the Galaxy at radii $a_n \simeq 40 {\rm kpc}/n$ for $n = 1,2,3 ..$. The recently discovered Monoceros Ring of stars is located near the $n=2$ caustic, prompting us to consider a possible connection between these two objects. We identify two processes through which the Monoceros Ring of star

  28. Mauricio Mondragon, Alejandro Perez, Carlo Rovelli

    We introduce a simple quantum mechanical model in which time and space are discrete and periodic. These features avoid the complications related to continuous-spectrum operators and infinite-norm states. The model provides a tool for discussing the probabilistic interpretation of generally-covariant quantum systems, without the confusion generated by spuriou

  29. S. E. Bisschop, G. W. Fuchs, A. C. A. Boogert, E. F. van Dishoeck

    Context: HCOOH is one of the more common species in interstellar ices with abundances of 1-5% with respect to solid H2O. Aims: This study aims at characterizing the HCOOH spectral features in astrophysically relevant ice mixtures in order to interpret astronomical data. Methods: The ices are grown under high vacuum conditions and spectra are recorded in tran

  30. David S. Spiegel, Zoltan Haiman, B. Scott Gaudi

    We investigate the effect of planetary rotation on the transit spectrum of an extrasolar giant planet. During ingress and egress, absorption features arising from the planet's atmosphere are Doppler shifted by of order the planet's rotational velocity (~1-2 km/s) relative to where they would be if the planet were not rotating. We focus in particular on the c

  31. Rodolfo M. Pussente, Valmir C. Barbosa

    We introduce a distributed algorithm for clock synchronization in sensor networks. Our algorithm assumes that nodes in the network only know their immediate neighborhoods and an upper bound on the network's diameter. Clock-synchronization messages are only sent as part of the communication, assumed reasonably frequent, that already takes place among nodes. T

  32. Kostas Skenderis, Paul K. Townsend, Antoine Van Proeyen

    We realize the domain-wall/cosmology correspondence for (pseudo)supersymmetric domain walls (cosmologies) in the context of four-dimensional supergravity. The OSp(2|4)-invariant anti-de Sitter (adS) vacuum of a particular N=2 Maxwell-Einstein supergravity theory is shown to correspond to the OSp(2^*|2,2)-invariant de Sitter (dS) vacuum of a particular pseudo

  33. M. V. Bondarko

    This paper is dedicated to triangulated categories endowed with weight structures (a new notion; D. Pauksztello has independently introduced them as co-t-structures). This axiomatizes the properties of stupid truncations of complexes in $K(B)$. We also construct weight structures for Voevodsky's categories of motives and for various categories of spectra. A

  34. Kasper K. S. Andersen, Jesper Grodal

    In this paper we completely classify which graded polynomial R-algebras in finitely many even degree variables can occur as the singular cohomology of a space with coefficients in R, a 1960 question of N. E. Steenrod, for a commutative ring R satisfying mild conditions. In the fundamental case R = Z, our result states that the only polynomial cohomology ring

  35. Aaron S. Keys, Sharon C. Glotzer

    Using molecular simulations, we show that the aperiodic growth of quasicrystals is controlled by the ability of the growing quasicrystal `nucleus' to incorporate kinetically trapped atoms into the solid phase with minimal rearrangement. In the system under investigation, which forms a dodecagonal quasicrystal, we show that this process occurs through the ass

  36. Michael R. Douglas, Jessie Shelton, Gonzalo Torroba

    We analyze supersymmetry breaking by anti-self-dual flux in the deformed conifold. This theory has been argued to be a dual realization of susy breaking by antibranes. As such, one might expect it to lead to a hierarchically small breaking scale, but only if the warp factor is taken into account. We verify this by explicitly computing the warp-modified modul

  37. E. O. Iltan

    We study the radiative lepton flavor violating l_i -> l_j\gamma decays in the two Higgs doublet model, respecting the Randall Sundrum scenario and estimate the contributions of the KK modes of left (right) handed charged lepton doublets (singlets) on the branching ratios. We observe that the branching ratios are sensitive to the contributions of the charged

  38. S. N. Fedosov, A. E. Sergeeva, A. F. Butenko

    Using short circuit and open circuit modifications of the thermally stimulated depolarization current technique, relaxation currents have been measured in corona poled copolymer of vinylidene fluoride with tetrafluoroethylene in samples stored after poling for either 1 day, or 16 month. Two well structured peaks observed in aged samples were attributed to re

  39. Luca Belluzzi, Javier Trujillo Bueno, Egidio Landi Degl'Innocenti

    The physical interpretation of the spectral line polarization produced by the joint action of the Hanle and Zeeman effects offers a unique opportunity to obtain empirical information about hidden aspects of solar and stellar magnetism. To this end, it is important to achieve a complete understanding of the sensitivity of the emergent spectral line polarizati

  40. Chuan Liu

    Several years ago, we proposed a modification of the Standard Model, in which the Higgs sector was stabilized by the addition of higher derivative operators, similar to Lee-Wick Electrodynamics. We studied this theory extensively, both using continuum Hamiltonian and path integral methods. We also reported detailed lattice studies of the higher derivative Hi

  41. Arnold W. Miller

    We show that it is relatively consistent with ZF that the Borel hierarchy on the reals has length $\omega_2$. This implies that $\omega_1$ has countable cofinality, so the axiom of choice fails very badly in our model. A similar argument produces models of ZF in which the Borel hierarchy has length any given limit ordinal less than $\omega_2$, e.g., $\omega$

  42. G. N. Burlak, A. B. Klimov

    We numerically study the dynamical excitations in Bose-Einstein condensate (BEC) placed in periodic and quasi-periodic 2D optical lattice (OL). In case of the repulsive mean-field interaction the BEC quantum tunnelling leads to a progressive soliton's splitting and generating of secondary solitons, which migrate to closest trapping potential minima. A nontri

  43. Peter Arnold, Po-Shan Leang

    Plasma instabilities can play a fundamental role in quark-gluon plasma equilibration in the high energy (weak coupling) limit. Early simulations of the evolution of plasma instabilities in non-abelian gauge theory, performed in one spatial dimension, found behavior qualitatively similar to traditional QED plasmas. Later simulations of the fully three-dimensi

  44. Kheira Ameur, Masahico Saito

    Cocycles are constructed by polynomial expressions for Alexander quandles. As applications, non-triviality of some quandle homology groups are proved, and quandle cocycle invariants of knots are studied. In particular, for an infinite family of quandles, the non-triviality of quandle homology groups is proved for all odd dimensions.

  45. Dawei Chen

    Consider genus $g$ curves that admit degree $d$ covers to elliptic curves only branched at one point with a fixed ramification type. The locus of such covers forms a one parameter family $Y$ that naturally maps into the moduli space of stable genus $g$ curves $\bar{\mathcal M}_{g}$. We study the geometry of $Y$, and produce a combinatorial method by which to

  46. Lev Birbrair, Dirk Siersma

    In this paper we show that the tangent cone of a conflict set in $R^n$ is a linear affine cone over a conflict set of smaller dimension and has dimension $n-1$. Moreover we give an example where the conflict sets is not normally embedded and not locally bi-Lipschitz equivalent to the corresponding tangent cone.

  47. A. Kogut, J. Dunkley, C. L. Bennett, O. Doré

    We present a full-sky model of polarized Galactic microwave emission based on three years of observations by the Wilkinson Microwave Anisotropy Probe (WMAP) at frequencies from 23 to 94 GHz. The model compares maps of the Stokes Q and U components from each of the 5 WMAP frequency bands in order to separate synchrotron from dust emission, taking into account

  48. Alexei Chepelianskii, Frédéric Chevy, Elie Raphael

    We investigate theoretically and experimentally the capillary-gravity waves created by a small object moving steadily at the water-air interface along a circular trajectory. It is well established that, for straight uniform motion, no steady waves appear at velocities below the minimum phase velocity $c_{min} = 23 \rm{cm \cdot s}^{-1}$. We show theoretically

  49. Michael Robinson

    A nonlinear parabolic differential equation with a quadratic nonlinearity is presented which has at least one equilibrium. The linearization about this equilibrium is asymptotically stable, but by using a technique inspired by H. Fujita, we show that the equilibrium is unstable in the nonlinear setting. The perturbations used have the property that they are

  50. Nathanial P. Brown, Andrew S. Toms

    Building on work of Elliott and coworkers, we present three applications of the Cuntz semigroup: (i) for many simple C$^*$-algebras, the Thomsen semigroup is recovered functorially from the Elliott invariant, and this yields a new proof of Elliott's classification theorem for simple, unital AI algebras; (ii) for the algebras in (i), classification of their H

  51. Ana Firan, Ryszard Stroynowski

    We evaluate the partial widths for internal conversions in the Higgs decays to two photons. For the Higgs masses of interest at LHC in the range of 100-150 GeV, the conversions to pairs of fermions represent significant fraction of Higgs decays.

  52. Walid S. Saba

    We argue for a compositional semantics grounded in a strongly typed ontology that reflects our commonsense view of the world and the way we talk about it. Assuming such a structure we show that the semantics of various natural language phenomena may become nearly trivial.

  53. M. Ibison

    We sketch the derivation of a Newtonian gravity-like force emerging from a direct-action variant of classical electromagnetism. The binding energy is a consequence of maximal phase correlation of the sources mediated by approximately monochromatic direct-action fields. The resulting force then has the character of a strong version of the van der Waals force,

  54. Sergiu I. Vacaru

    A generalized geometric method is developed for constructing exact solutions of gravitational field equations in Einstein theory and generalizations. First, we apply the formalism of nonholonomic frame deformations (formally considered for nonholonomic manifolds and Finsler spaces) when the gravitational field equations transform into systems of nonlinear pa

  55. I. Bakas, C. Sourdis

    The mean curvature flow describes the parabolic deformation of embedded branes in Riemannian geometry driven by their extrinsic mean curvature vector, which is typically associated to surface tension forces. It is the gradient flow of the area functional, and, as such, it is naturally identified with the boundary renormalization group equation of Dirichlet s

  56. V. B. Semikoz, J. W. F. Valle

    Primordial cosmological hypermagnetic fields polarize the early Universe plasma prior to the electroweak phase transition (EWPT). As a result of the long range parity violating gauge interaction present in the Standard Model their magnitude gets amplified, opening a new, perturbative way, of accounting for the observed intergalactic magnetic fields.

  57. Boris Krippa

    We study the exact renormalisation group flow for ultracold Fermi-gases in unitary regime. We introduce a pairing field to describe the formation of the Cooper pairs, and take a simple ansatz for the effective action. Set of approximate flow equations for the effective couplings including boson and fermionic fluctuations is derived. At some value of the runn

  58. Vasily Ogryzko

    Schroedinger's book 'What is Life?' is widely credited for having played a crucial role in development of molecular and cellular biology. My essay revisits the issues raised by this book from the modern perspective of epigenetics and systems biology. I contrast two classes of potential mechanisms of epigenetic stability: 'epigenetic templating' and 'systems

  59. Julien Barre

    We address the problem of retrieving information from a noisy version of the ``knowledge networks'' introduced by Maslov and Zhang. We map this problem onto a disordered statistical mechanics model, which opens the door to many analytical and numerical approaches. We give the replica symmetric solution, compare with numerical simulations, and finally discuss

  60. Hanfei Yan, Jorg Maser, Albert Macrander, Qun Shen

    We present a formalism of x-ray dynamical diffraction from volume diffractive optics with large numerical aperture and high aspect ratio, in an analogy to the Takagi-Taupin equations for strained single crystals. We derive a set of basic equations for dynamical diffraction from volume diffractive optics, which enable us to study the focusing property of thes

  61. Ben Gripaios, Stephen M. West

    We consider, in the effective field theory context, anomalies of gauge field theories on a slice of a five-dimensional, Anti-de Sitter geometry and their four-dimensional, holographic duals. A consistent effective field theory description can always be found, notwithstanding the presence of the anomalies and without modifying the degrees of freedom of the th

  62. Ivan Penkov, Gregg Zuckerman

    We study cohomological induction for a pair $(\frak g,\frak k)$, $\frak g$ being an infinite dimensional locally reductive Lie algebra and $\frak k \subset\frak g$ being of the form $\frak k_0 + C_\gg(\frak k_0)$, where $\frak k_0\subset\frak g$ is a finite dimensional reductive in $\frak g$ subalgebra and $C_{\gg} (\frak k_0)$ is the centralizer of $\frak k

  63. M. M. Falla Solórzano, L. E. Bolivar-Marinez, S. T. Perez-Merchancano

    The melanin is a group of biological pigments commonly found in living beings, it can be classified in three groups: eumelanin human beings, pheomelanins in animals, and allomelanins in the vegetal kingdom. There is a special interest in the eumelanin because this biopolymer exhibits the typical properties of a semiconductor. Eumelanin is also responsible of

  64. T. Klose, T. McLoughlin, J. A. Minahan, K. Zarembo

    We study the AdS_5 x S^5 sigma-model truncated to the near-flat-space limit to two-loops in perturbation theory. In addition to extending previously known one-loop results to the full SU(2|2)^2 S-matrix we calculate the two-loop correction to the dispersion relation and then compute the complete two-loop S-matrix. The result of the perturbative calculation c

  65. Maria Manuel Clementino, Dirk Hofmann

    It is known since 1973 that Lawvere's notion of (Cauchy-)complete enriched category is meaningful for metric spaces: it captures exactly Cauchy-complete metric spaces. In this paper we introduce the corresponding notion of Lawvere completeness for $(\mathbb{T},\mathsf{V})$-categories and show that it has an interesting meaning for topological spaces and quas

  66. R Springell, S W Zochowski, R C C Ward, M R Wells

    SQUID magnetometry and polarised neutron reflectivity measurements have been employed to characterise the magnetic properties of U/Fe, U/Co and U/Gd multilayers. The field dependence of the magnetisation was measured at 10K in magnetic fields from -70kOe to 70kOe. A temperature dependent study of the magnetisation evolution was undertaken for a selection of

  67. Audrey Cottet

    The description of the proximity effect in superconducting/ferromagnetic heterostructures requires to use spin-dependent boundary conditions. Such boundary conditions must take into account the spin dependence of the phase shifts acquired by electrons upon scattering on the boundaries of ferromagnets. The present article shows that this property can strongly

  68. Julian A. Zuñiga, O. L. Hernandez-Rosero, S. T. Perez-Merchancano

    In this work the influence of the electric and magnetic fields over a tunneling particle in a rectangular potential barrier is shown, we have taken into account the presence of an impurity at the barrier center and the effects of a hydrostatic pressure parallel to the barrier height considering the BenDaniel-Duke boundary conditions. Given that the particle

  69. Alexei Yu. Karlovich

    Suppose $\Gamma$ is a Carleson Jordan curve with logarithmic whirl points, $\varrho$ is a Khvedelidze weight, $p:\Gamma\to(1,\infty)$ is a continuous function satisfying $|p(\tau)-p(t)|\le -\mathrm{const}/\log|\tau-t|$ for $|\tau-t|\le 1/2$, and $L^{p(\cdot)}(\Gamma,\varrho)$ is a weighted generalized Lebesgue space with variable exponent. We prove that all

  70. P. J. Salazar-Valencia, L. E. Bolivar-Marinez, S. T. Perez-Merchancano

    The perylene-3,4,9,10-tetracarboxylic-dianhydride (PTCDA) and 1,4,5,8-naphthalene-tetracaboxylic-dianhydride (NTCDA) are planar pi-stacking organic molecules that have been shown to be excellent model compounds for studying the growth and optoelectronic properties of organic semiconductor thin films, particularly organic diodes. Some observations have shown

  71. Ch. Strelow, C. M. Schultz, H. Rehberg, H. Welsch

    We report on microtube ring resonators with quantum wells embedded as an optically active material. Optical modes are observed over a broad energy range. Their properties strongly depend on the exact geometry of the microtube along its axis. In particular we observe (i) preferential emission of light on the inside edge of the microtube and (ii) confinement o

  72. S. T. Perez-Merchancano, G. E. Marques, L. E. Bolivar-Marinez

    The PTCDA (3,4,9,10-Perylene-tetracarboxylic dianhydride) and the NTCDA (1,4,5,8-Naphtalenetetracarboxylic dianhydride) are aromatic, stable, planar and highly symmetric with unusual electrical properties. The PTCDA is a semiconductor organic crystalline of particular interest due to its excellent properties and electronic potential that are used in optoelec

  73. Sheng Yang, Jean-Claude Belfiore

    In this two-part paper, we consider the multiantenna multihop relay channels in which the source signal arrives at the destination through N independent relaying hops in series. The main concern of this work is to design relaying strategies that utilize efficiently the relays in such a way that the diversity is maximized. In part I, we focus on the amplify-a

  74. A. Czarnecki, W. J. Marciano, A. Sirlin

    Electroweak radiative corrections to muon capture on nuclei are computed and found to be sizable. They enhance the capture rates for hydrogen and helium by 2.8% and 3.0% respectively. As a result, the value of the induced pseudoscalar coupling, g_P^exp, extracted from a recent hydrogen 1S singlet capture experiment is increased by about 21% to g_P^exp = 7.3

  75. A. Fleszar, M. Potthoff, W. Hanke

    Using the local spin-density approximation (LSDA) and the (non self-consistent) GW approach, the (quasi-particle) band structure is calculated for MnTe in zinc-blende geometry. Different parameters characterizing the electronic structure are computed for an antiferromagnetic and the ferromagnetic phase and compared with the experiment. The strong Hubbard-typ

  76. Gary R. Goldstein

    Dick Dalitz produced lasting contributions to particle physics for 50 years. Along with Dalitz pairs, Dalitz plots and CDD poles, he did major work in parity violation, hyperon resonance identification, the quark model, and hypernuclei. These topics will be summarized, with some emphasis on the author's collaboration with Dalitz on quark spin and fragmentati

  77. F. Martinez-Vidal

    We report on the measurement of the Cabibbo-Kobayashi-Maskawa angle gamma through a Dalitz analysis of neutral D decays to K0s pi- pi+ in the processes B-+ -> D^(*) K-+ and B-+ -> D K^*-+, D^* -> D pi0, D gamma, with the Babar detector at the SLAC PEP-II e^+ e^- asymmetric-energy collider.

  78. P. Ajith, S. Babak, Y. Chen, M. Hewitson

    Recent progress in numerical relativity has enabled us to model the non-perturbative merger phase of the binary black-hole coalescence problem. Based on these results, we propose a phenomenological family of waveforms which can model the inspiral, merger, and ring-down stages of black hole coalescence. We also construct a template bank using this family of w

  79. Andreas Mueller, Bernd Aschenbach

    It has been recently demonstrated that the orbital velocity profile around Kerr black holes in the equatorial plane as observed in the locally non-rotating frame exhibits a non-monotonic radial behaviour. We show here that this unexpected minimum-maximum feature of the orbital velocity remains if the Kerr vacuum is generalized to the Kerr-de Sitter or Kerr-a

  80. Christine Noot-Huyghe

    One proves a Beilinson-Bernstein theorem in the context of arithmetic D-modules introduced by Berthelot, for flag varieties. This generalizes in the arithmetic context previous results of Brylinski-Kashiwara and Beilinson-Bernstein in the complex case.

  81. Pablo Arrighi, Renan Fargetton, Zizhu Wang

    We give a one-dimensional quantum cellular automaton (QCA) capable of simulating all others. By this we mean that the initial configuration and the local transition rule of any one-dimensional QCA can be encoded within the initial configuration of the universal QCA. Several steps of the universal QCA will then correspond to one step of the simulated QCA. The

  82. Sergei V. Kalinin, Brian J. Rodriguez, Stephen Jesse, Katyayani Seal

    Electromechanical coupling is ubiquitous in biological systems with examples ranging from simple piezoelectricity in calcified and connective tissues to voltage-gated ion channels, energy storage in mitochondria, and electromechanical activity in cardiac myocytes and outer hair cell stereocilia. Piezoresponse force microscopy (PFM) has originally emerged as

  83. J. Craig Wheeler, Justyn R. Maund, Shizuka Akiyama

    All core collapse supernovae are strongly aspherical. The "Bochum event," with velocity components displaced symmetrically about the principal H$\alpha$ line, strongly suggests that SN 1987A was a bi-polar rather than a uni-polar explosion. While there is a general tendency to display a single prominant axis in images and spectropolarimetry, there is also gr

  84. Naceur Gaaloul, Amine Jaouadi, Mourad Telmini, Laurence Pruvost

    The manipulation of cold atoms with optical fields is a very promising technique for a variety of applications ranging from laser cooling and trapping to coherent atom transport and matter wave interferometry. Optical fields have also been proposed as interesting tools for quantum information processing with cold atoms. In this paper, we present a theoretica

  85. Jia-Lin Zhu, Dong Xu

    The polarization splitting of the exciton ground state in two laterally coupled quantum dots under an in-plane electric field is investigated and its effective tuning is designed. It is found that there are significant Stark effect and anticrossing in energy levels. Due to coupling between inter- and intra-dot states, the absolute value of polarization split

  86. G. J. D. Petrie, J. W. S. Blokland, R. Keppens

    We present numerical magnetohydrostatic solutions describing the gravitationally stratified, bulk equilibrium of cool, dense prominence plasma embedded in a near-potential coronal field. These solutions are calculated using the FINESSE magnetohydrodynamics equilibrium solver and describe the morphologies of magnetic field distributions in and around prominen

  87. P. Sjolund, S. J. H. Petra, C. M. Dion, H. Hagman

    We present here a detailed study of the behaviour of a three dimensional Brownian motor based on cold atoms in a double optical lattice [P. Sjolund et al., Phys. Rev. Lett. 96, 190602 (2006)]. This includes both experiments and numerical simulations of a Brownian particle. The potentials used are spatially and temporally symmetric, but combined spatiotempora

  88. G. Bonvicini, CLEO Collaboration

    Using 281 pb^{-1} of data recorded by the CLEO-c detector in e^+e^- collisions at the psi(3770), corresponding to 0.78 million D^+D^- pairs, we investigate the substructure of the decay D^+ to pi^- pi^+ pi^+ using the Dalitz plot technique. We find that our data are consistent with the following intermediate states: rho(770)pi^+, f_2(1270)pi^+, f_0(1370)pi^+

  89. P. Roy Chowdhury, D. N. Basu, C. Samanta

    Theoretical estimates of $\alpha$-decay half lives of several nuclei in the decay from element 113 are presented. Calculations in a WKB framework using DDM3Y interaction and experimental Q-values are in good agreement with the experimental data. Half life calculations are found to be quite sensitive to the Q-values and angular momenta transfers. Calculated d

  90. P. H. Chavanis

    Starting from the Liouville equation, we derive the exact hierarchy of equations satisfied by the reduced distribution functions of the single species point vortex gas in two dimensions. Considering an expansion of the solution in powers of 1/N in a proper thermodynamic limit $N\to +\infty$, and neglecting some collective effects, we derive a kinetic equatio

  91. Gregory Derfel, Peter J. Grabner, Fritz Vogl

    The asymptotic behaviour of the solutions of Poincar\'e's functional equation $f(\lambda z)=p(f(z))$ ($\lambda>1$) for $p$ a real polynomial of degree $\geq2$ is studied in angular regions of the complex plain. The constancy of an occurring periodic function is characterised in terms of geometric properties of the Julia set of $p$. For real Julia sets we giv

  92. Nigel P. Byott, G. Griffith Elder

    Ramification invariants are necessary, but not in general sufficient, to determine the Galois module structure of ideals in local number field extensions. This insufficiency is associated with elementary abelian extensions, where one can define a refined ramification filtration -- one with more ramification breaks [JNTB 17 (2005)]. The first refined break nu

  93. Wei Huang, Wang Xu, Mu-Lin Yan

    In the strong uniform magnetic field, the noncommutative plane (NCP) caused by the lowest Landau level (LLL) effect, and QED with NCP (QED-NCP) are studied. Being similar to the condensed matter theory of quantum Hall effect, an effective filling factor $f(B)$ is introduced to character the possibility that the electrons stay on the LLL. The analytic and num

  94. Biqin Huang, Lai Zhao, Douwe J. Monsma, Ian Appelbaum

    Efficient injection of spin-polarized electrons into the conduction band of silicon is limited by the formation of a silicide at the ferromagnetic metal (FM)/silicon interface. In the present work, this "magnetically-dead" silicide (where strong spin-scattering significantly reduces injected spin polarization) is eliminated by moving the FM in the spin injec

  95. Alexey K. Mazur

    The probability distributions for bending angles in double helical DNA obtained in all-atom molecular dynamics simulations are compared with theoretical predictions. The computed distributions remarkably agree with the worm-like chain theory for double helices of one helical turn and longer, and qualitatively differ from predictions of the semi-elastic chain

  96. R Springell, S W Zochowski, R C C Ward, M R Wells

    This paper addresses the structural characterisation of a series of U/Fe, U/Co and U/Gd multilayers. X-ray reflectivity has been employed to investigate the layer thickness and roughness parameters along the growth direction and high-angle diffraction measurements have been used to determine the crystal structure and orientation of the layers. For the case o

  97. Bjørn Ian Dundas, Harald Øyen Kittang

    We extend Geisser and Hesselholt's result on ``bi-relative K-theory'' from discrete rings to connective ring spectra. That is, if $\mathcal A$ is a homotopy cartesian $n$-cube of ring spectra (satisfying connectivity hypotheses), then the $(n+1)$-cube induced by the cyclotomic trace $$K(\mathcal A)\to TC(\mathcal A)$$ is homotopy cartesian after profinite co

  98. Jean-Baptiste Masson, Guilhem Gallot

    Interaction between metal surface waves and periodic geometry of subwavelength structures is at the core of the recent but crucial renewal of interest in plasmonics. One of the most intriguing points is the observation of abnormal strong transmission through these periodic structures, which can exceed by orders of magnitude the classical transmission given b

  99. Vasiliy Kantsler, Enrico Segre, Victor Steinberg

    We present experimental results on the relaxation dynamics of vesicles subjected to a time-dependent elongation flow. We observed and characterized a new instability, which results in the formation of higher order modes of the vesicle shape (wrinkles), after a switch in the direction of the gradient of the velocity. This surprising generation of membrane wri

  100. L. Fuhrmann, J. A. Zensus, T. P. Krichbaum, E. Angelakis

    The Large Area Telescope (LAT) instrument onboard GLAST offers a tremendous opportunity for future blazar studies. In order to fully benefit from its capabilities and to maximize the scientific return from the LAT, it is of great importance to conduct dedicated multi-frequency monitoring campaigns that will result comprehensive observations. Consequently, we