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July 2007 arXiv papers — page 11

Showing 1,001–1,100 of 4,643 papers

  1. J. Clemente-Gallardo, G. Marmo

    We present a geometrical description of the space of density states of a quantum system of finite dimension. After presenting a brief summary of the geometrical formulation of Quantum Mechanics, we proceed to describe the space of density states $\D(\Hil)$ from a geometrical perspective identifying the stratification associated to the natural $GL(\Hil)$--act

  2. R. Nahnhauer, A. A. Rostovtsev, D. Tosi

    The detection of cosmic neutrinos with energies above 1017 eV got growing interest during recent years. Possible target materials for in-matter arrays of ~100 km3 size under discussion are water, ice and rock salt. Here we propose to investigate permafrost as an additional alternative, covering ~20% of Earth land surface and reaching down to more than 1000 m

  3. Lars Kadison

    We introduce a notion of depth three tower of three rings C < B < A with depth two ring extension A | B recovered when B = C. If A = \End B_C and B | C is a Frobenius extension, this captures the notion of depth three for a Frobenius extension in arXiv:math/0107064 and arXiv:math/0108067, such that if B | C is depth three, then A | C is depth two (a phenomen

  4. Klaus Kirsten, Paul Loya

    It is shown how the pre-exponential factor of the Feynman propagator for a large class of potentials can be computed using contour integrals. This is of direct relevance in the context of tunnelling processes in quantum theories. The prerequisites for this analysis are accessible to advanced undergraduate students and involve only introductory courses in ord

  5. Paul R. Anderson, Emil Mottola, Ruslan Vaulin

    The effective action associated with the trace anomaly provides a general algorithm for approximating the expectation value of the stress tensor of conformal matter fields in arbitrary curved spacetimes. In static, spherically symmetric spacetimes, the algorithm involves solving a fourth order linear differential equation in the radial coordinate r for the t

  6. ZEUS Collaboration, S. Chekanov

    Three- and four-jet final states have been measured in photoproduction at HERA using the ZEUS detector with an integrated luminosity of 121 pb^-1. The results are presented for jets with transverse energy E_T^jet>6 GeV and pseudorapidity |eta^jet|<2.4, in the kinematic region given by the virtuality of the photon Q^2<1 GeV^2 and the inelasticity 0.2<y<0.85 a

  7. Kenichi Bannai, Guido Kings

    The specializations of the motivic elliptic polylog are called motivic Eisenstein classes. For applications to special values of L-Functions, it is important to compute the realizations of these classes. In this paper, we prove that the syntomic realization of the motivic Eisenstein classes, restricted to the ordinary locus of the modular curve, may be expre

  8. Emmanuel Roy

    We show that a stationary IDp process (i.e., an infinitely divisible stationary process without Gaussian part) can be written as the independent sum of four stationary IDp processes, each of them belonging to a different class characterized by its Lévy measure. The ergodic properties of each class are, respectively, nonergodicity, weak mixing, mixing of all

  9. Andrei Rodin

    I propose a notion of theory motivated by Category theory.

  10. V. Joergens, A. Mueller

    We report the discovery of a 16-20 Jupiter mass radial velocity companion around the very young (~3 Myr) brown dwarf candidate ChaHa8 (M5.75-M6.5). Based on high-resolution echelle spectra of ChaHa8 taken between 2000 and 2007 with UVES at the VLT, a companion was detected through RV variability with a semi-amplitude of 1.6 km/s. A Kepler fit to the data yie

  11. M. Viallet, H. Baty

    The long term magnetohydrodynamic stability of magnetized transonic/supersonic jets is numerically investigated using a spatial approach. We focus on two-dimensional linearly-unstable slab configurations where the jet is embedded in a flow-aligned uniform magnetic field of weak amplitude. We compare our results with previous studies using a temporal approach

  12. Ke Wu, Wei-Zhong Zhao, Han-Ying Guo

    In a way similar to the continuous case formally, we define in different but equivalent manners the difference discrete connection and curvature on discrete vector bundle over the regular lattice as base space. We deal with the difference operators as the discrete counterparts of the derivatives based upon the differential calculus on the lattice. One of the

  13. D. S. Golubev, A. D. Zaikin

    With the aid of the Keldysh technique we develop a microscopic theory of non-local electron transport in three-terminal NSN structures consisting of a chaotic superconducting quantum dot attached to one superconducting and two normal electrodes. Our theory fully accounts for non-equilibrium effects and disorder in a superconducting terminal. We go beyond per

  14. Ehud Behar, Raanan Nordon, Noam Soker

    We analyze velocity profiles of the X-ray spectral lines emitted by the Eta Carinae stellar binary at four epochs, just before the X-ray minimum (associated with periastron) and more than two years before the minimum (~apastron). The profiles are nicely resolved by the HETGS spectrometer on board Chandra. Far from periastron, we find symmetrical lines that a

  15. S. Mechkov, G. Oshanin, M. Rauscher, M. Brinkmann

    Within the framework of a semi-microscopic interface displacement model we analyze the linear stability of sessile ridges and drops of a non-volatile liquid on a homogeneous, partially wet substrate, for both signs and arbitrary amplitudes of the three-phase contact line tension. Focusing on perturbations which correspond to deformations of the three-phase c

  16. Jean-François Renaud, Bruno Rémillard

    In this paper, we construct a Malliavin derivative for functionals of square-integrable Lévy processes and derive a Clark-Ocone formula. The Malliavin derivative is defined via chaos expansions involving stochastic integrals with respect to Brownian motion and Poisson random measure. As an illustration, we compute the explicit martingale representation for t

  17. A. Tongas, D. Tsoubelis, P. Xenitidis

    We consider lattice equations on ${\mathds{Z}}^2$ which are autonomous, affine linear and possess the symmetries of the square. Some basic properties of equations of this type are derived, as well as a sufficient linearization condition and a conservation law. A systematic analysis of the Lie point and the generalized three- and five-point symmetries is pres

  18. Ingemar Kaj, Lasse Leskelä, Ilkka Norros, Volker Schmidt

    This paper studies the limits of a spatial random field generated by uniformly scattered random sets, as the density $λ$ of the sets grows to infinity and the mean volume $ρ$ of the sets tends to zero. Assuming that the volume distribution has a regularly varying tail with infinite variance, we show that the centered and renormalized random field can have th

  19. A. Lobel, R. Blomme

    We discuss the development of the new radiative transfer code Wind3D. It solves the non-LTE radiative transport problem in moving stellar atmosphere models in three geometric dimensions. The code accepts arbitrary 3D velocity fields in Cartesian geometry without assumptions of axial symmetry. Wind3D is currently implemented as a fully parallelized (exact) ac

  20. Francois Richard

    Assuming that first significant results from LHC become available, this presentation assumes 4 different scenarios and discuss the implications for ILC

  21. A. Lobel

    SpectroWeb is an online maintained interactive graphical database of digital spectral atlases of spectral standard stars at http://spectra.freeshell.org . It is an efficient and user-friendly research tool for accurate analyses of stellar spectra observed with large spectral resolution, including the solar spectrum. The web-interface displays observed and th

  22. N M Oliveira-Neto, E M F Curado, M A Rego-Monteiro

    In this article we introduce a class of generalisations of the Jordan-Schwinger (JS) map which realises the recent proposed generalised sl(2) (G-sl(2)) algebra via two independent Generalised Heisenberg Algebras (GHA). Although the GHA and the G-sl(2) algebra exhibit more general algebraic structures than the Heisenberg and sl(2) algebras, the generalised JS

  23. Konstantin Klemm, Christoph Flamm, Peter F. Stadler

    Local minima and the saddle points separating them in the energy landscape are known to dominate the dynamics of biopolymer folding. Here we introduce a notion of a &#34;folding funnel&#34; that is concisely defined in terms of energy minima and saddle points, while at the same time conforming to a notion of a &#34;folding funnel&#34; as it is discussed in t

  24. Maria Concetta Palumbo, Lorenzo Farina, Alberto De Santis, Alessandro Giuliani

    The maintainance of a stable periodicity during the yeast metabolic cycle involving approximately half of the genome requires a very strict and efficient control of gene expression. For this reason, the metabolic cycle is a very good candidate for testing the role of a class of post-transcriptional regulators, the so called PUF-family, whose genome-wide mRNA

  25. James W. Dufty

    Granular fluids consist of collections of activated mesoscopic or macroscopic particles (e.g., powders or grains) whose flows often appear similar to those of normal fluids. To explore the qualitative and quantitative description of these flows an idealized model for such fluids, a system of smooth inelastic hard spheres, is considered. The single feature di

  26. S. Kimura, T. Takeuchi, K. Okunishi, M. Hagiwara

    High-field specific heat measurements on BaCo2V2O8, which is a good realization of an S = 1/2 quasi one-dimensional Ising-like antifferomagnet, have been performed in magnetic fields up to 12 T along the chain and at temperature down to 200 mK. We have found a new magnetic ordered state in the field-induced phase above Hc ~ 3.9 T. We suggest that a novel typ

  27. P. V. Dong, D. T. Huong, N. T. Thuy, H. N. Long

    We explore the Higgs sector in the supersymmetric economical 3-3-1 model and find new features in this sector. The charged Higgs sector is revised i.e., in difference of the previous work, the exact eigenvalues and states are obtained without any approximation. In this model, there are three Higgs bosons having masses equal to that of the gauge bosons--the W

  28. Tetsuya Asai

    The rationality of the elliptic Gauss sum coefficient is shown. The following is a specific case of our argument. Let f(u)=sl((1-i)\varpi u), where sl() is the Gauss&#39; lemniscatic sine and \varpi=2.62205... is the real period of the elliptic curve y^2=x^3-x, so that f(u) is an elliptic function relative to the period lattice Z[i]. Let πbe a primary prime

  29. D. U. Matrasulov, J. R. Yusupov, P. K. Khabibullaev, A. A. Saidov

    The Casimir effects for one-dimensional fractal networks, so-called quantum graphs is studied. Based on the Green function approach for quantum graphs zero-point energy for some simplest topologies is written explicitly.

  30. B. W. A. Leurs, K. E. Luna, J. Zaanen

    We discuss the issue of phase separation in the SU(2) slave boson theory of Wen and Lee of the doped Mott insulator. It is shown that the constraint structure of the theory leads to the interpretation of the holons to have hard-core interactions, which is demonstrated further by studying the empty limit (no electrons). Surprisingly, with hard-core interactio

  31. L. Schoeffel

    The most important results on subnuclear diffractive phenomena obtained at HERA and Tevtaron are reviewed and new issues in nucleon tomography are discussed. Some challenges for understanding diffraction at the LHC, including the discovering of the Higgs boson, are outlined.

  32. U. De Giovannini, F. Cavaliere, R. Cenni, M. Sassetti

    We report results for the ground state energies and wave functions obtained by projecting spatially unrestricted Hartree Fock states to eigenstates of the total spin and the angular momentum for harmonic quantum dots with $N\leq 12$ interacting electrons including a magnetic field states with the correct spatial and spin symmetries have lower energies than t

  33. Ion Spanulescu, Anca Gheorghiu

    Most of the econometric and econophysics models have been borrowed from the statistical physics, and as a cosequence, a new interdisciplinary science called econophysics has emerged. In this paper we planned to extend the analogy between different economic processes or phenomena and processes and phenomena from different fields of physics, other than statist

  34. Christian Romelsberger

    We develop techniques to calculate an index for four dimensional superconformal field theories. This superconformal index is counting BPS operators which preserve only one supercharge. To calculate the superconformal index we quantize the field theory on S^3 X R and show that the twisted theory has an appropriate mass gap. This allows for the interactions to

  35. U. Zülicke, R. Winkler, J. Bolte

    We present a unified description of zitterbewegung-like phenomena for electron and hole systems showing Rashba spin splitting as well as for electrons in single-layer and bilayer graphene. The former class of systems can be interpreted as &#34;nonrelativistic&#34; whereas the latter are often called &#34;ultrarelativistic&#34; so that our unified description

  36. T. P. Simula, N. Nygaard, S. X. Hu, L. A. Collins

    Full, three dimensional, time-dependent simulations are presented demonstrating the quantized transfer of angular momentum to a Bose-Einstein condensate from a laser carrying orbital angular momentum in a Laguerre-Gaussian mode. The process is described in terms of coherent Bragg scattering of atoms from a chiral optical lattice. The transfer efficiency and

  37. O. Mryglod, Yu. Holovatch

    In this paper we use several approaches to analyse a scientific journal as a complex system and to make a possibly more complete description of its current state and evolution. Methods of complex networks theory, statistics, and queueing theory are used in this study. As a subject of the analysis we have chosen the journal ``Condensed Matter Physics&#39;&#39

  38. Vasil G. Bregadze, Eteri S. Gelagutashvili, Irene G. Khutsishvili, Khatuna G. Sologashvili

    We have managed to correlate the stability constants of complex formation, which can be registered in equilibrium state, to the dynamic characteristic of the complex lifetime. Thus, the principal concept of molecular biophysics regarding biomolecule, structure-dynamics-function can be reformatted as structure-stability-function. It should be specially noted

  39. L. Smrcka, N. A. Goncharuk, P. Svoboda, P. Vasek

    We report on magnetotransport measurements in two MBE-grown GaAs/AlGaAs superlattices formed by wide and narrow quantum wells and thin Si-doped barriers subject to tilted magnetic fields. It has been shown that illumination of the strongly coupled superlattice with narrow wells leads to reduction of its dimensionality from the 3D to 2D. The illumination-indu

  40. J. L. Zdunik, M. Bejger, P. Haensel, E. Gourgoulhon

    We calculate the energy release associated with a strong first-order phase transition, from normal phase N to an &#34;exotic&#34; superdense phase S, in a rotating neutron star. Such a phase transition, accompanied by a density jump rho_N --> rho_S, is characterized by rho_S/rho_N > 3/2(1+P_0/rho_N c^2), where P_0 is the pressure, at which phase transition o

  41. Alfredo Iorio, Siddhartha Sen

    We conjecture that certain patterns (scars), theoretically and numerically predicted to be formed by electrons arranged on a sphere to minimize the repulsive Coulomb potential (the Thomson problem) and experimentally found in spherical crystals formed by self-assembled polystyrene beads (an instance of the generalized Thomson problem), could be relevant to e

  42. Yoshifumi R. Shimizu, Takuya Shoji, Masayuki Matsuzaki

    By the very definition the triaxial deformation parameter $γ$ is related to the expectation values of the K=0 and K=2 components of the intrinsic quadrupole tensor operator. On the other hand, using the same symbol &#34;$γ$&#34;, various different parametrizations of triaxial deformation have been employed, which are suitable for various types of the mean-fi

  43. Adrian Signer

    We combine the fixed-order evaluation of the $b\bar{b}$ sum rules with a non-relativistic effective-theory approach. The combined result for the $n$-th moment includes all terms suppressed with respect to the leading-order result by ${\cal O}(α_s^3)$ and ${\cal O}((α_s \sqrt{n})^l α_s^2)$, counting $α_s \sqrt{n} \sim 1$. When compared to experimental data, t

  44. Donghe Pei, Lingling Kong, Jianguo Sun, Qi Wang

    We define the notions of $S_t^1\times S_s^1$-valued lightcone Gauss maps, lightcone pedal surface and Lorentzian lightcone height function of Lorentzian surface in semi-Euclidean 4-space and established the relationships between singularities of these objects and geometric invariants of the surface as applications of standard techniques of singularity theory

  45. Ulf Leonhardt, Thomas G. Philbin

    Transformation media are at the heart of invisibility devices, perfect lenses and artificial black holes. In this paper, we consider their quantum theory. We show how transformation media map quantum electromagnetism in physical space to QED in empty flat space.

  46. Sintayehu Tesfa

    We study the harmonic entanglement and squeezing in a two-mode radiation produced in a degenerate parametric down conversion process coupled to a two-mode vacuum reservoir employing the linearization procedure. It is found that there is a quadrature entanglement between the harmonically related fundamental and second-harmonic modes and the superimposed radia

  47. K. Hattori, K. Miyake

    The physical origin of frequency dependence in elastic constants, which are often found in an ultrasound propagation in filled skutterudites and clathrate compounds, is investigated theoretically. This dependence arises from a coupling between the acoustic phonon and some optical phonons, which strongly interact with electrons. Using a self-consistent ladder

  48. Alberto Blasi, Nicola Maggiore

    We consider the noncommutative extension of Chern-Simons theory. We show the the theory can be fully expanded in power series of the noncommutative parameter theta and that no non-analytical sector exists. The theory appears to be unstable under radiative corrections, but we show that the infinite set of instabilities, to all orders in \hbar and in theta, is

  49. Louis H. Kauffman, Samuel J. Lomonaco

    We review the q-deformed spin network approach to topological quantum field theory and apply these methods to produce unitary representations of the braid groups that are dense in the unitary groups. The simplest case of these models is the Fibonacci model, itself universal for quantum computation. We here formulate these braid group representations in a sha

  50. Abhijit Bhattacharyya, Sanjay K. Ghosh, Ritam Mallick, Sibaji Raha

    We investigate the General Relativistic (GR) effects on the conversion from nuclear to two-flavour quark matter in compact stars, both static as well as rotating. We find that GR effects lead to qualitative differences in rotating stars, indicating the inadequacy of non-relativistic (NR) or even Special Relativistic (SR) treatments for these cases.

  51. L. Smrcka, N. A. Goncharuk, M. Orlita, R. Grill

    We have studied Bloch electrons in a perfect unidirectional superlattice subject to crossed electric and magnetic fields, where the magnetic field is oriented ``in-plane&#39;&#39;, i.e. in parallel to the sample plane. Two orientation of the electric field are considered. It is shown that the magnetic field suppresses the intersubband tunneling of the Zener

  52. Damien Chablat, Jorge Angeles

    A spherical wrist of the serial type is said to be isotropic if it can attain a posture whereby the singular values of its Jacobian matrix are all identical and nonzero. What isotropy brings about is robustness to manufacturing, assembly, and measurement errors, thereby guaranteeing a maximum orientation accuracy. In this paper we investigate the existence o

  53. Jean Mairesse

    We consider the recursive equation ``x(n+1)=A(n)x(n)&#39;&#39; where x(n+1) and x(n) are column vectors of size k and where A(n) is an irreducible random matrix of size k x k. The matrix-vector multiplication in the (max,+) algebra is defined by (A(n)x(n))_i= max_j [ A(n)_{ij} +x(n)_j ]. This type of equation can be used to represent the evolution of Stochas

  54. Xu Cheng, Cameron Dale, Jiangchuan Liu

    Established in 2005, YouTube has become the most successful Internet site providing a new generation of short video sharing service. Today, YouTube alone comprises approximately 20% of all HTTP traffic, or nearly 10% of all traffic on the Internet. Understanding the features of YouTube and similar video sharing sites is thus crucial to their sustainable deve

  55. R. S. Sutherland, G. V. Bicknell

    We present three dimensional simulations of the interaction of a light hypersonic jet with an inhomogeneous thermal and turbulently supported disk in an elliptical galaxy, including Radio and multi-band X-ray visualisations. These simulations are applicable to the GPS/CSS phase of some extragalactic radio sources. We identify four generic phases in the evolu

  56. R. S. Sutherland, G. V. Bicknell

    We present three dimensional simulations of the interaction of a light hypersonic jet with an inhomogeneous thermal and turbulently supported disk in an elliptical galaxy. We model the jet as a light, supersonic non-relativistic flow with parameters selected to be consistent with a relativistic jet with kinetic power just above the FR1/FR2 break. We identify

  57. Yilmaz Simsek

    The purpose of this paper is to construct p-adic Dedekind sums and Hardy-Berndt type sums. We also construct generating function of the twisted Bernoulli polynomials and functions. Furthermore, we give some discussions on elliptic analogue of the Apostol-Dedekind sums.

  58. Philippe Wenger, Damien Chablat

    This paper describes a new parallel kinematic architecture for machining applications: the orthoglide. This machine features three fixed parallel linear joints which are mounted orthogonally and a mobile platform which moves in the Cartesian x-y-z space with fixed orientation. The main interest of the orthoglide is that it takes benefit from the advantages o

  59. Philippe Wenger, Clément Gosselin, Damien Chablat

    Parallel kinematic mechanisms are interesting alternative designs for machining applications. Three 2-DOF parallel mechanism architectures dedicated to machining applications are studied in this paper. The three mechanisms have two constant length struts gliding along fixed linear actuated joints with different relative orientation. The comparative study is

  60. Tewodros Amdeberhan, Victor H. Moll

    We provide an analytic expression for the Laplace transform of the digamma fuction. This complements work of L. Glasser, D. Manna and O. Oloa on this question. The Laplace transform is continuous in the Laplace-variable a. The derivative admits a jump at a= ln 2.

  61. Daniel R. Claes, Gregory R. Snow

    The Cosmic Ray Observatory Project (CROP) is a statewide education and research experiment involving Nebraska high school students, teachers and university undergraduates in the study of extensive cosmic-ray air showers. A network of high school teams construct, install, and operate school-based detectors in coordination with University of Nebraska physics p

  62. Alexander D. Wissner-Gross

    Individual cellular automata rules are attractive models for a range of biological and physical self-assembling systems. While coexpression and coevolution are common in such systems, ensembles of cellular automata rules remain poorly understood. Here we report the first known analysis of the equally weighted ensemble of all elementary cellular automata (ECA

  63. Gregory R. Snow

    The scale and scope of the physics studied at the Auger Observatory offer significant opportunities for original outreach work. Education, outreach, and public relations of the Auger collaboration are coordinated in a task of its own whose goals are to encourage and support a wide range of efforts that link schools and the public with the Auger scientists an

  64. C. Ogle

    We show that the image of Connes-Karoubi-Chern character, restricted to the image of the Baum-Connes assembly map in the Bott-periodized topological K-theory of the complex group algebra, lies in the elliptic summand of the (periodic) cyclic homology of the group algebra. This implies that for any (weighted) ell-1 completion of the group algebra, rational su

  65. Roy Montalvo, Hitoshi Nishino, Subhash Rajpoot

    We couple a recently-established N=1 globally supersymmetric self-dual Yang-Mills multiplet in three dimensions to supergravity. This becomes possible due to our previous result on globally supersymmetric formulation based on a compensator multiplet. We further couple the self-dual vector to a supersymmetric sigma-model on the coset SO(8,n) / SO(8) X SO(n) v

  66. Walter T. Giele, David A. Kosower, Peter Z. Skands

    We present a simple formalism for parton-shower Markov chains. As a first step towards more complete uncertainty bands, we incorporate a comprehensive exploration of the ambiguities inherent in such calculations. To reduce this uncertainty, we then introduce a matching formalism which allows a generated event sample to simultaneously reproduce any infrared s

  67. Hock-Seng Goh, Christopher A. Krenke

    We present a twin Higgs model based on left-right symmetry with a tree level quartic. This is made possible by extending the symmetry of the model to include two Z_2 parities, each of which is sufficient to protect the Higgs from getting a quadratically divergent mass squared. Although both parities are broken explicitly, the symmetries that protect the Higg

  68. V. Barger, Y. Gao, Wai-Yee Keung

    $\cal T$-parity in the Little Higgs model could be violated by anomalies that allow the lightest $\cal T$-odd $A_H$ to decay into $ZZ$ and $W^+W^-$. We analyze these anomaly induced decays and the two-particle and the three-particle decay modes of other heavy quarks and bosons in this model which yield unique Large Hadron Collider (LHC) signals with fully re

  69. D. Leibfried, E. Knill, C. Ospelkaus, D. J. Wineland

    Many efforts are currently underway to build a device capable of large scale quantum information processing (QIP). Whereas QIP has been demonstrated for a few qubits in several systems, many technical difficulties must be overcome in order to construct a large-scale device. In one proposal for large-scale QIP, trapped ions are manipulated by precisely contro

  70. Thiem Hoang, Alex Lazarian

    We study the physical processes that affect the alignment of grains subject to radiative torques (RATs). To describe the action of RATs, we use the analytical model (AMO) of RATs introduced in Paper I. We focus our discussion on the alignment by anisotropic radiation flux with respect to magnetic field, which defines the axis of grain Larmor precession. Such

  71. D. Rogalski

    Let k be an algebraically closed field, let K/k be a finitely generated field extension of transcendence degree 2 with automorphism sigma, and let A be an N-graded subalgebra of Q = K[t; sigma] with A_n finite dimensional over k for all n. Then if A is big enough in Q in an appropriate sense, we prove that GKdim A = 3,4,5 or is infinite, with the exact value

  72. Andre S. Ribeiro, Stuart A. Kauffman, Jason Lloyd-Price, Björn Samuelsson

    The amount of mutual information contained in time series of two elements gives a measure of how well their activities are coordinated. In a large, complex network of interacting elements, such as a genetic regulatory network within a cell, the average of the mutual information over all pairs <I> is a global measure of how well the system can coordinate its

  73. Bartłomiej Siudeja

    Lower bounds estimates are proved for the first eigenvalue for the Dirichlet Laplacian on arbitrary triangles using various symmetrization techniques. These results can viewed as a generalization of Pólya&#39;s isoperimetric bounds. It is also shown that amongst triangles, the equilateral triangle minimizes the spectral gap and (under additional assumption)

  74. Paschalis Karageorgis, John G. Stalker

    Sharp bounds are obtained, under a variety of assumptions on the eigenvalues of the Einstein tensor, for the ratio of the Hawking mass to the areal radius in static, spherically symmetric space-times.

  75. B. Andrei Bernevig, F. D. M. Haldane

    We describe an occupation-number-like picture of Fractional Quantum Hall (FQH) states in terms of polynomial wavefunctions characterized by a dominant occupation-number configuration. The bosonic variants of single-component abelian and non-abelian FQH states are modeled by Jacks (Jack symmetric polynomials), characterized by dominant occupation-number confi

  76. Alexander Tiskin

    A classical measure of string comparison is given by the longest common subsequence (LCS) problem on a pair of strings. We consider its generalisation, called the semi-local LCS problem, which arises naturally in many string-related problems. The semi-local LCS problem asks for the LCS scores for each of the input strings against every substring of the other

  77. Edward S. Letzter, Linhong Wang

    We study the &#34;q-commutative&#34; power series ring R:=k_q[[x_1,...,x_n]], defined by the relations x_ix_j = q_{ij}x_j x_i, for multiplicatively antisymmetric scalars q_{ij} in a field k. Our results provide a detailed account of prime ideal structure for a class of noncommutative, complete, local, noetherian domains having arbitrarily high (but finite) K

  78. Ming-Hao Liu, Gustav Bihlmayer, Stefan Blügel, Ching-Ray Chang

    Local spin and charge densities on a two-dimensional honeycomb lattice are calculated by the Landauer-Keldysh formalism (LKF). Through the empirical tight-binding method, we show how the realistic band structure can be brought into the LKF. Taking the Bi(111) surface, on which strong surface states and Rashba spin-orbit coupling are present [Phys. Rev. Lett.

  79. Thimo Rohlf

    We calculate analytically the critical connectivity $K_c$ of Random Threshold Networks (RTN) for homogeneous and inhomogeneous thresholds, and confirm the results by numerical simulations. We find a super-linear increase of $K_c$ with the (average) absolute threshold $|h|$, which approaches $K_c(|h|) \sim h^2/(2\ln{|h|})$ for large $|h|$, and show that this

  80. Vijay Balasubramanian, Jan de Boer, Vishnu Jejjala, Joan Simon

    We construct the microstates of near-extremal black holes in AdS_5 x S^5 as gases of defects distributed in heavy BPS operators in the dual SU(N) Yang-Mills theory. These defects describe open strings on spherical D3-branes in the S^5, and we show that they dominate the entropy by directly enumerating them and comparing the results with a partition sum calcu

  81. Behcet Alpat

    The Alpha Magnetic Spectrometer (AMS02) experiment will be installed in 2009 on the International Space Station (ISS) for an operational period of at least three years. The purpose of AMS02 experiment is to perform accurate, high statistics, long duration measurements in space of charged cosmic rays in rigidity range from 1 GV to 3 TV and of high energy phot

  82. I. L. Bogolubsky, V. G. Bornyakov, G. Burgio, E. -M. Ilgenfritz

    For the gluon propagator of pure SU(2) lattice gauge theory in the Landau gauge we investigate the effect of Gribov copies and finite-volume effects. Concerning gauge fixing, we enlarge the accessible gauge orbits by adding non-periodic Z(2) gauge transformations and systematically employ the simulated annealing algorithm. Strategies to keep all Z(2) sectors

  83. V. N. Berestovskii, C. Plaut

    We show that every inner metric space X is the metric quotient of a complete R-tree via a free isometric action, which we call the covering R-tree of X. The quotient mapping is a weak submetry (hence, open) and light. In the case of compact 1-dimensional geodesic space X, the free isometric action is via a subgroup of the fundamental group of X. In particula

  84. Conrad Plaut

    We prove that an equivalent condition for a uniform space to be coverable is that the images of the natural projections in the fundamental inverse system are uniformly open in a certain sense. As corollaries we (1) obtain a concrete way to find covering entourage, (2) correct an error in [3] and (3) show that coverable is equivalent to chain connected and un

  85. Nicolas Libedinsky

    The Soergel category B of a Coxeter system (W,S) is a bimodule category over a polynomial algebra on which W acts. It&#39;s a categorification of the Hecke Algebra of (W,S). In this article we give a combinatorial description of morphism spaces in B. As a corollary, we give an analogous description of the morphisms in O_0-proj, where O_0 is the principal blo

  86. Vladimir Retakh, Robert Lee Wilson

    We construct and study a class of algebras associated to generalized layered graphs, i.e. directed graphs with a ranking function on their vertices. Each finite directed acyclic graph admits countably many structures of a generalized layered graph. We construct linear bases in such algebras and compute their Hilbert series. Our interest to generalized layere

  87. Cullen H. Blake, Guillermo Torres, Joshua S. Bloom, B. Scott Gaudi

    We present observations of a new low-mass double-lined eclipsing binary system discovered using repeat observations of the celestial equator from the Sloan Digital Sky Survey II. Using near-infrared photometry and optical spectroscopy we have measured the properties of this short-period [P=0.407037(14) d] system and its two components. We find the following

  88. K. B. Gubbels, H. T. C. Stoof

    We determine the physical properties of \emph{p}-wave Feshbach molecules in doubly spin-polarized $^{40}$K and find excellent agreement with recent experiments. We show that these molecules have a large probability $Z$ to be in the closed channel or bare molecular state responsible for the Feshbach resonance. In the superfluid state this allows for observati

  89. Lawrence J. Hall, Michael P. Salem, Taizan Watari

    The flavor structure of the Standard Model might arise from random selection on a landscape. We propose a class of simple models, ``Gaussian landscapes,&#39;&#39; where Yukawa couplings derive from overlap integrals of Gaussian wavefunctions on extra-dimensions. Statistics of vacua are generated by scanning the peak positions of these zero-modes, giving prob

  90. Ana Alboteanu, Thorsten Ohl, Reinhold Rückl

    We derive the most general Seiberg-Witten maps for noncommutative gauge theories in second order of the noncommutative parameter theta. Our results reveal the existence of more ambiguities than previously known. In particular, we demonstrate that some of these ambiguities enter observables like scattering cross sections and enlarge the parameter space of the

  91. A. V. Anisovich, V. Kleber, E. Klempt, V. A. Nikonov

    A partial wave analysis is presented of data on photoproduction of hyperons including single and double polarization observables. The large spin transfer probability reported by the CLAS collaboration can be successfully described with an isobar partial wave analysis.

  92. V. A. Nikonov, A. V. Anisovich, E. Klempt, A. V. Sarantsev

    We report further evidence for $N(1900)P_{13}$ from an analysis of a large variety of photo- and pion-induced reactions, in particular from the new CLAS measurements of double polarization observables for photoproduction of hyperons. The data are consistent with two classes of solutions both requiring contributions from $N(1900)P_{13}$ but giving different $

  93. Davide L. Ferrario, Alessandro Portaluri

    Consider n=2l>=4 point particles with equal masses in space, subject to the following symmetry constraint: at each instant they form an orbit of the dihedral group D_l, where D_l is the group of order 2l generated by two rotations of angle pi around two secant lines in space meeting at an angle of pi/l. By adding a homogeneous gravitational (Newtonian) poten

  94. Francesco Giacosa, Giuseppe Pagliara

    In this work we study the spectral functions of scalar mesons in one- and two-channel cases. When the propagators satisfy the Källen-Lehman representation a normalized spectral function is obtained, allowing to take into account finite-width effects in the evaluation of decay rates. In the one-channel case, suitable to the light sigma and k mesons, the spect

  95. Lawrence J. Hall, Michael P. Salem, Taizan Watari

    The fundamental theory of nature may allow a large landscape of vacua. Even if the theory contains a unified gauge symmetry, the 22 flavor parameters of the Standard Model, including neutrino masses, may be largely determined by the statistics of this landscape, and not by any symmetry. Then the measured values of the flavor parameters do not lead to any fun

  96. U. Thoma, M. Fuchs, A. V. Anisovich, G. Anton

    Decays of baryon resonances in the second and the third resonance region into N pi0 pi0 are studied by photoproduction of two neutral pions off protons. Partial decay widths of N* and Delta* resonances decaying into Delta(1232) pi, N(ππ)_{S}, N(1440)P_{11} pi, and N(1520)D_{13} pi are determined in a partial wave analysis of this data, and data from other re

  97. A. V. Sarantsev

    Properties of the Roper resonance, the first scalar excitation of the nucleon, are determined. Pole positions and residues of the $P_{11}$ partial wave are studied in a combined analysis of pion- and photo-induced reactions. We find the Roper pole at $\{(1371\pm7)-i(92\pm10)\}$ MeV and an elasticity of $0.61\pm 0.03$. The largest decay coupling is found for

  98. Chiranjib Sur, Rajat K Chaudhuri

    Searching for an accurate optical clock which can serve as a better time standard than the present day atomic clock is highly demanding from several areas of science and technology. Several attempts have been made to built more accurate clocks with different ion species. In this article we discuss the electric quadrupole and hyperfine shifts in the $5d^{9}6s

  99. S. Kaviraj, L. A. Kirkby, J. Silk, M. Sarzi

    We present the first large-scale study of E+A (post-starburst) galaxies that incorporates photometry in the ultraviolet (UV) wavelengths. We find that the starburst that creates the E+A galaxy typically takes place within the last Gyr and creates a high fraction (20-60 percent) of the stellar mass in the remnant over a short timescale (< 0.1 Gyrs). We find a

  100. Dominic Joyce

    A Kuranishi space is a topological space with a Kuranishi structure, defined by Fukaya and Ono. Kuranishi structures occur naturally on moduli spaces of J-holomorphic curves in symplectic geometry. Let Y be an orbifold and R a commutative ring or Q-algebra. We define two kinds of Kuranishi homology KH_*(Y;R). The chain complex KC_*(Y;R) defining KH_*(Y;R) is