February 2009 arXiv papers — page 39

Sunil Ahuja, Clarence W. Rowley

We present an estimator-based control design procedure for flow control, using reduced-order models of the governing equations, linearized about a possibly unstable steady state. The reduced models are obtained using an approximate balanced truncation method that retains the most controllable and observable modes of the system. The original method is valid o

Vladlen G. Shvedov, Anton S. Desyatnikov, Andrei V. Rode, Wieslaw Z. Krolikowski

We introduce a novel approach for all-optical trapping and manipulation of absorbing aerosol particles based on a photophoretic force. We demonstrate experimentally, in open air, the robust three-dimensional guiding of agglomerates of carbon nanoparticles with the size spanned for two orders of magnitude, from 100 nanometers to 10 microns, over the distances

Akira Onuki

Equilibrium properties of dilute binary fluid mixtures are studied in two-phase states on the basis of a Helmholtz free energy including the gradient free energy. The solute partitioning between gas and liquid (Henry's law) and the surface tension change $Δγ$ are discussed. A derivation of the Gibbs law $Δγ=-TΓ$ is given with $Γ$ being the surface adsorp

A. A. Minzoni, L. R. Juarez, M. Rosenbaum

We show that the Moyal *-product on the algebra of fields induces an effective lattice structure on vortex dynamics which can be explicitly constructed using recent asymptotic results.

Lorenzo Sironi, Aristotle Socrates

We present a feedback mechanism for supermassive black holes and their host bulges that operates during epochs of radio-loud quasar activity. In the radio cores of relativistic quasar jets, internal shocks convert a fraction of ordered bulk kinetic energy into randomized relativistic ions, or in other words cosmic rays. By employing a phenomenologically-moti

V. Sauli

The propagator of confined quarks is calculated for timelike momenta by transforming Minkowski Greens functions to the Temporal Euclidean space. Based on the framework of the Schwinger-Dyson equations the QCD quark propagator is obtained in two approximations which differ by assuming behaviour of gluon propagator. In both studied cases we get universal resul

Shung-ichi Ando, Judith A. McGovern, Toru Sato

In this paper we explore the time-reversal-odd triple-correlation coefficient in neutron beta decay, the so-called "D coefficient", using heavy-baryon effective field theory with photon degrees of freedom. We find that this framework allows us to reproduce the known results for the contribution which comes from final-state interactions, and also to discuss h

Cenalo Vaz, L. C. R. Wijewardhana

Popular approaches to quantum gravity describe black hole microstates differently and apply different statistics to count them. Since the relationship between the approaches is not clear, this obscures the role of statistics in calculating the black hole entropy. We address this issue by discussing the entropy of eternal AdS black holes in dimension four and

Savvas Nesseris, Anupam Mazumdar

We consider corrections to the Einstein-Hilbert action which contain both higher order and nonlocal terms. We derive an effective Newtonian gravitational constant applicable at the weak field limit and use the primordial nucleosynthesis (BBN) bound and the local gravity constraints on $G_{eff}$ in order to test the viability of several cases of our general L

Hyun-chul Lee, Guy Worthey, John P. Blakeslee

We investigate the effects of alpha-element enhancement and the thermally pulsing-asymptotic giant branch (TP-AGB) stars on the surface brightness fluctuation (SBF) magnitudes and broadband colors of simple stellar populations and compare to the empirical calibrations. We consider a broad range of ages and metallicities using the recently updated Teramo BaST

Cheng Li, Dimitri A. Gadotti, Shude Mao, Guinevere Kauffmann

We study the clustering properties of barred galaxies using data from the Sloan Digital Sky Survey (SDSS). We compute projected redshift-space two-point cross-correlation functions w_p(r_p) for a sample of nearly 1000 galaxies for which we have performed detailed structural decompositions using the methods described in Gadotti (2009). The sample includes 286

John W. Barrett, R. J. Dowdall, Winston J. Fairbairn, Henrique Gomes

The semiclassical limit of a 4-simplex amplitude for a spin foam quantum gravity model with an Immirzi parameter is studied. If the boundary state represents a non-degenerate 4-simplex geometry, the asymptotic formula contains the Regge action for general relativity. A canonical choice of phase for the boundary state is introduced and is shown to be necessar

Qi Zhang, Huaizhong Zhao

In this paper we develop a new weak convergence and compact embedding method to study the existence and uniqueness of the $L_ρ^2({\mathbb{R}^{d}};{\mathbb{R}^{1}})\otimes L_ρ^2({\mathbb{R}^{d}};{\mathbb{R}^{d}})$ valued solution of backward stochastic differential equations with p-growth coefficients. Then we establish the probabilistic representation of the

Slavik Jablan, Ljiljana Radovic, Radmila Sazdanovic

This article contains general formulas for Tutte and Jones polynomial for families of knots and links given in Conway notation.

Panagiota Daskalopoulos, Richard Hamilton, Natasa Sesum

We consider an ancient solution $g(\cdot,t)$ of the Ricci flow on a compact surface that exists for $t\in (-\infty,T)$ and becomes spherical at time $t=T$. We prove that the metric $g(\cdot,t)$ is either a family of contracting spheres, which is a type I ancient solution, or a Rosenau solution, which is a type II ancient solution.

Daniel Green, Bart Horn, Leonardo Senatore, Eva Silverstein

We analyze a distinctive mechanism for inflation in which particle production slows down a scalar field on a steep potential, and show how it descends from angular moduli in string compactifications. The analysis of density perturbations -- taking into account the integrated effect of the produced particles and their quantum fluctuations -- requires somewhat

Francois Ledrappier, Seonhee Lim

We characterize the volume entropy of an arbitrary regular building as the topological pressure of the geodesic flow on an apartment. We show that the Liouville measure is not entropy maximizing measure for regular hyperbolic buildings. As a consequence, we obtain a strict lower bound on the volume entropy in terms of the branching numbers and the volume of

Daniel Vieira, K. Capelle, C. A. Ullrich

The exact exchange-correlation (XC) potential in time-dependent density-functional theory (TDDFT) is known to develop steps and discontinuities upon change of the particle number in spatially confined regions or isolated subsystems. We demonstrate that the self-interaction corrected adiabatic local-density approximation for the XC potential has this property

Mark Wurtz, Randy Lewis, T. G. Steele

The SU(2)-Higgs model, with a single Higgs field in the fundamental representation and a quartic self-interaction, has a Higgs region and a confinement region which are analytically connected in the parameter space of the theory; these regions thus represent a single phase. The effect of multiple Higgs fields on this phase structure is examined via Monte Car

John M. Fregeau, Harvey B. Richer, Frederic A. Rasio, Jarrod R. Hurley

Recent observations of the white dwarf (WD) populations in the Galactic globular cluster NGC 6397 suggest that WDs receive a kick of a few km/s shortly before they are born. Using our Monte Carlo cluster evolution code, which includes accurate treatments of all relevant physical processes operating in globular clusters, we study the effects of the kicks on t

Rachid Ahl Laamara, Adil Belhaj, Luis J. Boya, Antonio Segui

We discuss local F-theory geometries and theirs gauge theory dualities in terms of intersecting D7-branes wrapped four-cycles in Type IIB superstring. The manifolds are built as elliptic K3 surface fibrations over intersecting F_0=CP^1 \times CP^1 base geometry according to ADE Dynkin Diagrams. The base is obtained by blowing up the extended ADE hyper-Kahler

Louigi Addario-Berry, Svante Janson, Colin McDiarmid

The spread of a connected graph G was introduced by Alon, Boppana and Spencer (1998) and measures how tightly connected the graph is. It is defined as the maximum over all Lipschitz functions f on V(G) of the variance of f(X) when X is uniformly distributed on V(G). We investigate the spread for certain models of sparse random graph; in particular for random

A. Cabrera, P. Adamson, M. Barker, A. Belias

MINOS is a long baseline neutrino oscillation experiment that uses two detectors separated by 734 km. The readout systems used for the two detectors are different and have to be independently calibrated. To verify and make a direct comparison of the calibrated response of the two readout systems, test beam data were acquired using a smaller calibration detec

Karl Auinger, Igor Dolinka, Mikhail Volkov

We study matrix identities involving multiplication and unary operations such as transposition or Moore-Penrose inversion. We prove that in many cases such identities admit no finite basis.

César Galindo

A graded tensor category over a group $G$ will be called a strongly $G$-graded tensor category if every homogeneous component has at least one multiplicativily invertible object. Our main result is a description of the module categories over a strongly $G$-graded tensor category as induced from module categories over tensor subcategories associated with the

Turan Birol, Piet W. Brouwer

We calculate the contribution to the spin transfer torque from sequential tunneling through impurities in a magnetic tunnel junction. For a junction with weakly polarized ferromagnetic contacts, the torque is found to be in the plane spanned by the magnetizations of the ferromagnetic contacts and proportional to $\sin θ$, where $θ$ is the angle between the m

B. Seradjeh, J. E. Moore, M. Franz

An odd number of gapless Dirac fermions is guaranteed to exist at a surface of a strong topological insulator. We show that in a thin-film geometry and under external bias, electron-hole pairs that reside in these surface states can condense to form a coherent exciton condensate, similar in general terms to the exciton condensate recently argued to exist in

V. Straizys, V. Laugalys

The slopes of interstellar reddening lines in the 2MASS J-H versus H-Ks diagrams for 26 areas in the inner Galaxy (from Vulpecula to Centaurus) are determined. For this aim we use the red-clump giants located inside and behind spiral arms, or behind dense dust clouds of the Local arm. In most of the investigated directions the ratio E(J-H)/E(H-K_s) is found

Hans D. Mittelmann, Frank Vallentin

The kissing number in n-dimensional Euclidean space is the maximal number of non-overlapping unit spheres which simultaneously can touch a central unit sphere. Bachoc and Vallentin developed a method to find upper bounds for the kissing number based on semidefinite programming. This paper is a report on high accuracy calculations of these upper bounds for n

Hélène Esnault, Olivier Wittenberg

For a smooth and geometrically irreducible variety X over a field k, the quotient of the absolute Galois group G_{k(X)} by the commutator subgroup of G_{\bar k(X)} projects onto G_k. We investigate the sections of this projection. We show that such sections correspond to "infinite divisions" of the elementary obstruction of Colliot-Thélène and Sansuc

S. Boucksom, A. Broustet, G. Pacienza

We explain how to deduce from recent results in the Minimal Model Program a general uniruledness theorem for base loci of adjoint divisors. We also show how to recover special cases by extending a technique introduced by Takayama.

Paul H. Frampton, Shinya Matsuzaki

Generalizing a previous model to accommodate the third quark family and CP violation, we present a $T^{'}$ model which predicts tribimaximal neutrino (PMNS) mixings while the central predictions for quark mixings are $|V_{td}/V_{ts}| = 0.245$ and $|V_{ub}/V_{cb}| = 0.237$ with a predicted CP violating KM phase $δ_{KM} = 65.8^{0}$. All these are acceptabl

Spyros Alexakis

We derive a unique continuation theorem for the vacuum Einstein equations. Our method of proof utilizes Carleman estimates (most importantly one obtained recently by Ionescu and Klainerman), but also relies strongly on certain geometric gauge constructions which make it possible to address this problem via such estimates. We indicate how our method can be us

Mathieu Anel

This work presents a way to associate a Grothendieck site structure to a category endowed with a unique factorisation system of its arrows. In particular this recovers the Zariski and Etale topologies and others related to Voevodsky's cd-structures. As unique factorisation systems are also frequent outside algebraic geometry, a construction applies to so

V. A. Sheminova

We study the properties of solar magnetic fields on scales less than the spatial resolution of solar telescopes. A synthetic infrared spectropolarimetric diagnostics based on a 2D MHD simulation of magnetoconvection is used for this. We analyze two time sequences of snapshots that likely represent two regions of the network fields with their immediate surrou

Jun Koda, Milos Milosavljevic, Paul R. Shapiro

We study the formation of disk-dominated galaxies in a LCDM universe. Their existence is considered to be a challenge for the LCDM cosmology, because galaxy mergers isotropize stellar disks and trigger angular momentum transport in gas disks, thus fostering the formation of central stellar spheroids. Here, we postulate that the formation of stellar spheroids

J. L. Albacete, N. Armesto, J. G. Milhano, C. A. Salgado

We perform a global fit to the structure function F_2 measured in lepton-proton experiments at small values of Bjorken-x, x\le 0.01, for all experimentally available values of Q^2, 0.045 GeV^2\le Q^2 \le 800 GeV^2. We show that the recent improvements resulting from the inclusion of running coupling corrections allow for a description of data in terms of non

Tobias Meng, Pascal Simon, Serge Florens

We develop a general perturbative framework based on a superconducting atomic limit for the description of Andreev bound states (ABS) in interacting quantum dots connected to superconducting leads. A local effective Hamiltonian for dressed ABS, including both the atomic (or molecular) levels and the induced proximity effect on the dot is argued to be a natur

Ronny Richter

We consider two strongly hyperbolic Hamiltonian formulations of general relativity and their numerical integration with a free and a partially constrained symplectic integrator. In those formulations we use hyperbolic drivers for the shift and in one case also for the densitized lapse. A system where the densitized lapse is an external field allows to enforc

Peter Crooks, Robert Milson

We pose and solve the equivalence problem for subspaces of ${\mathcal P}_n$, the $(n+1)$ dimensional vector space of univariate polynomials of degree $\leq n$. The group of interest is ${\rm SL}_2$ acting by projective transformations on the Grassmannian variety ${\mathcal G}_k{\mathcal P}_n$ of $k$-dimensional subspaces. We establish the equivariance of the

Anirban Banerji, Aniket Magarkar

We feel happy when web-browsing operations provide us with necessary information; otherwise, we feel bitter. How to measure this happiness (or bitterness)? How does the profile of happiness grow and decay during the course of web-browsing? We propose a probabilistic framework that models evolution of user satisfaction, on top of his/her continuous frustratio

G. F. Chen, W. Z. Hu, J. L. Luo, N. L. Wang

Specific heat, resistivity, susceptibility and Hall coefficient measurements were performed on high-quality single crystalline Na$_{1-δ}$FeAs. This compound is found to undergo three successive phase transitions at around 52, 41, and 23 K, which correspond to structural, magnetic and superconducting transitions, respectively. The Hall effect result indicates

J. -M. Cai, W. Dür, M. Van den Nest, A. Miyake

Recently, a framework was established to systematically construct novel universal resource states for measurement-based quantum computation using techniques involving finitely correlated states. With these methods, universal states were found which are in certain ways much less entangled than the original cluster state model, and it was hence believed that w

G. Van Hooydonk

We probe Penrose's five-fold symmetry and fractal behavior for atom H. With radius r(H) derived from H mass m(H), H symmetry is governed by Euclid's golden ratio phi=0,5(sqrt(5)-1), as proved with accurate H terms. A Hund-type Mexican hat curve in the natural H spectrum points to mirrored antihydrogen Hbar. We predict that term H 1S-3S, to be measure

Marcin Markiewicz, Marcin Wiesniak

We present a perfect state transfer protocol via a qubit chain with the evolution governed by the $xx$ Hamiltonian. In contrast to the recent protocol announced in [Phys. Rev. Lett. {\bf 101}, 230502 (2008)], our method does not demand any remote-cooperated initialization and sending classical information about measurement outcomes. We achieve the perfect st

Murilo L. Tiago, Fernando A. Reboredo

We studied theoretically the optical properties of C$_{60}$ fullerene microcrystals as a function of hydrostatic pressure with first-principles many-body theories. Calculations of the electronic properties were done in the GW approximation. We computed electronic excited states in the crystal by diagonalizing the Bethe-Salpeter equation (BSE). Our results co

S. Weyeneth, T. Schneider, E. Giannini

We present reversible magnetization data of a high quality Bi2212 single crystal and explore the occurrence of 3D-xy critical behavior close to the bulk transition temperature Tc and of Kosterlitz-Thouless (KT) behavior. Below and above the presumed Kosterlitz-Thouless transition temperature T_KT we observe the characteristic 2D-xy behavior: a downward shift

David Wands, Anze Slosar

In this note we examine the derivation of scale-dependent bias due to primordial non-Gaussianity of the local type in the context of general relativity. We justify the use of the Poisson equation in general relativistic perturbation theory and thus the derivation of scale-dependent bias as a test of primordial non-Gaussianity, using the spherical collapse mo

A. Maisuradze, M. Nicklas, R. Gumeniuk, C. Baines

The filled skutterudite superconductor PrPt4Ge12 was studied in muon-spin rotation (muSR), specific heat, and electrical resistivity experiments. The continuous increase of the superfluid density with decreasing temperature and the dependence of the magnetic penetration depth λon the magnetic field obtained by means of muSR, as well as the observation of a T

V. V. Moshchalkov, M. Menghini, T. Nishio, Q. H. Chen

We demonstrate the existence of a novel superconducting state in high quality two-component MgB2 single crystalline superconductors where a unique combination of both type-1 (kappa_1 < 0.707) and type-2 (kappa_2 > 0.707) superconductor conditions is realized for the two components of the order parameter. This condition leads to a vortex-vortex interaction at

Sönke Niekamp, Tobias Wirth, Holger Frahm

We derive functional equations for the eigenvalues of the XXZ model subject to anti-diagonal twisted boundary conditions by means of fusion of transfer matrices and by Sklyanin&#39;s method of separation of variables. Our findings coincide with those obtained using Baxter&#39;s method and are compared to the recent solution of Galleas. As an application we s

Stéphane Druel

We study the divisorial Zariski decomposition on varieties whose first Chern class is zero. We first prove that any exceptional divisor is contractible (up to a birational map that is an isomorphism in codimension one). We then characterize prime exceptional divisors on holomorphic symplectic manifolds.

S. M. Nagiyev, E. I. Jafarov, M. Y. Efendiyev

The two-dimensional relativistic configurational $\vec r$-space is proposed and the exactly solvable finite-difference model of the harmonic oscillator in this space is constructed. The wave functions of the stationary states and the corresponding energy spectrum are found for the model under consideration. It is shown that, they have correct non-relativisti

Rajeev Kumar Jain, Pravabati Chingangbam, L. Sriramkumar

We investigate the problem of perturbative reheating and its effects on the evolution of the curvature perturbations in tachyonic inflationary models. We derive the equations governing the evolution of the scalar perturbations for a system consisting of a tachyon and a perfect fluid. Assuming the perfect fluid to be radiation, we solve the coupled equations

Reinhard Steffens, Thorsten Theobald

Let $g_1, ..., g_k$ be tropical polynomials in $n$ variables with Newton polytopes $P_1, ..., P_k$. We study combinatorial questions on the intersection of the tropical hypersurfaces defined by $g_1, ..., g_k$, such as the $f$-vector, the number of unbounded faces and (in case of a curve) the genus. Our point of departure is Vigeland&#39;s work who considere

A. Rubano, D. Paparo, F. Miletto, U. Scotti di Uccio

The blue-green photoluminescence emitted by pure and electron-doped strontium titanate under intense pulsed near-ultraviolet excitation is studied experimentally, as a function of excitation intensity and temperature. Both emission spectra and time-resolved decays of the emission are measured and analyzed in the framework of simple phenomenological models. W

Jonas Larson, Maciej Lewenstein

We consider a gas of ultracold two-level atoms confined in a cavity, taking into account for atomic center-of-mass motion and cavity mode variations. We use the generalized Dicke model, and analyze separately the cases of a Gaussian, and a standing wave mode shape. Owing to the interplay between external motional energies of the atoms and internal atomic and

Bhupinder Singh Anand

I show--contrary to common beliefs tolerated by the &#39;bosses&#39;--that any interpretation of ZF that admits Aristotle&#39;s particularisation is not sound; that the standard interpretation of PA is not sound; that PA is consistent but omega-inconsistent; that a sound finitary interpretation of PA is definable in terms of Turing-computability; and that PA

K. Stepien

A hydrodynamic model for the energy transport between the components of a contact binary is presented. Energy is transported by a large-scale, steady circulation carrying high entropy matter from the primary to secondary component. The circulation is driven by the baroclinic structure of the common envelope, which is a direct consequence of the nonuniform he

P. T. Nagy, P. Plaumann

In the year 1944 R. H. Bruck has described a very general construction method which he called the extension of a set by a quasigroup. We use it to construct a class of examples for LF-quasigroups in which the image of the map $e(x)=x\backslash x$ is a group. More generally, we consider the variety of quasigroups which is defined by the property that the map

Paul Tod

By an argument similar to that of Gibbons and Stewart (1984), we show that there are no weakly-asymptotically-simple, analytic vacuum or electrovac solutions of the Einstein equations which are periodic in time.

Nicolas Gillis, François Glineur

Nonnegative Matrix Factorization consists in (approximately) factorizing a nonnegative data matrix by the product of two low-rank nonnegative matrices. It has been successfully applied as a data analysis technique in numerous domains, e.g., text mining, image processing, microarray data analysis, collaborative filtering, etc. We introduce a novel approach to

Christian G. Boehmer, Tiberiu Harko

In this paper we qualitatively study radial solutions of the semilinear elliptic equation $Δu + u^n = 0$ with $u(0)=1$ and $u&#39;(0)=0$ on the positive real line, called the Emden-Fowler or Lane-Emden equation. This equation is of great importance in Newtonian astrophysics and the constant $n$ is called the polytropic index. By introducing a set of new vari

Vladimir Shevelev

With the uniform positions we prove theorems of Landau and Hardy-Littlwood type for Goldbach, Chen, Lemoine-Levy and other binary partitions of positive integers. We also pose some new conjectures.

Krassimir Yankov Iordjev, Dimiter Stoichkov Kovachev

In this paper, a class of combinatorial identities is proved. A method is used which is based on the following rule: counting elements of a given set in two ways and making equal the obtained results. This rule is known as &#34;counting in two ways&#34;. The principle of inclusion and exclusion is used for obtaining a class of (0,1)-matrices.

Glencora Borradaile, Erik D. Demaine, Siamak Tazari

We present the first polynomial-time approximation schemes (PTASes) for the following subset-connectivity problems in edge-weighted graphs of bounded genus: Steiner tree, low-connectivity survivable-network design, and subset TSP. The schemes run in O(n log n) time for graphs embedded on both orientable and non-orientable surfaces. This work generalizes the

Pierre Courrieu

This paper presents a generalization of the &#34;weighted least-squares&#34; (WLS), named &#34;weighted pairing least-squares&#34; (WPLS), which uses a rectangular weight matrix and is suitable for data alignment problems. Two fast solving methods, suitable for solving full rank systems as well as rank deficient systems, are studied. Computational experiment

A. Ibrahimbegovic, C. Knopf-Lenoir, A. Kucerova, P. Villon

In this work we deal with the optimal design and optimal control of structures undergoing large rotations. In other words, we show how to find the corresponding initial configuration and the corresponding set of multiple load parameters in order to recover a desired deformed configuration or some desirable features of the deformed configuration as specified

Sid Touati

The community of program optimisation and analysis, code performance evaluation, parallelisation and optimising compilation has published since many decades hundreds of research and engineering articles in major conferences and journals. These articles study efficient algorithms, strategies and techniques to accelerate programs execution times, or optimise o

I. E. Lyubin, M. V. Eremin, I. M. Eremin, H. Keller

The expressions for the superfluid density have been discussed in both weak and strong coupling approaches. The numerical calculations of temperature and isotope composition dependencies have been performed for a number of High-Tc compounds. The tight-binding parameters and corresponding Fermi surfaces are taken in accord to the available photoemission data.

Ross Pinsky

Consider a simple random walk on the integers with the following transition mechanism. At each site $x$, the probability of jumping to the right is $ω(x)\in[\frac12,1)$, until the first time the process jumps to the left from site $x$, from which time onward the probability of jumping to the right is $\frac12$. We investigate the transience/recurrence proper

R. C. Penner, Michael Knudsen, Carsten Wiuf, Joergen Ellegaard Andersen

We introduce a new model of proteins, which extends and enhances the traditional graphical representation by associating a combinatorial object called a fatgraph to any protein based upon its intrinsic geometry. Fatgraphs can easily be stored and manipulated as triples of permutations, and these methods are therefore amenable to fast computer implementation.

Jozef Strecka, Lucia Canova, Kazuhiko Minami

The spin-1/2 Ising-Heisenberg model with the pair XYZ Heisenberg interaction and quartic Ising interactions is exactly solved by establishing a precise mapping relationship with the corresponding zero-field (symmetric) eight-vertex model. It is shown that the Ising-Heisenberg model with the ferromagnetic Heisenberg interaction exhibits a striking critical be

Yunkyu Bang

We study the superfluid density of the $\pm$s-wave state of the minimal two band model for the Fe-based superconductors and its evolution with impurity concentration. We show that the impurity scattering of the strong coupling limit induces the selfenergy of a generic form $Im Σ_{imp} (ω) \approx i γ+ i βω$ beyond a critical impurity concentration $Γ_{imp} >

Peter B. Shalen

It is shown that, up to isometry, all but finitely many closed, orientable hyperbolic 3-manifolds with a given trace field $K$ admit 0.34 as a Margulis number. This is deduced from a more technical result giving a condition under which $\max(d(P,x\cdot P),d(P,y\cdot P))\ge0.34$ for every $P\in\HH^3$, where $x$ and $y$ lie in $\pizzle(E)$ for some number fiel

Mami Iwata, Shin-ichi Sasa

We study the simplest mode-coupling equation which describes the time correlation function of the spherical p-spin glass model. We formulate a systematic perturbation theory near the mode-coupling transition point by introducing multiple time scales. In this formulation, the invariance with respect to the dilatation of time in a late stage yields an arbitrar

Stephen Bruce Sontz

Referring to quantum mechanics, Einstein used to say &#34;The old one does not play dice.&#34; And this is true since the probability of quantum mechanics is not the classical probability of games such as dice. Historically this was the first example of a non-classical probability theory, which we introduce in this expository article using undergraduate line

Fanny Delebecque-Fendt, Florian Mehats

We study the limiting behavior of a singularly perturbed Schrödinger-Poisson system describing a 3-dimensional electron gas strongly confined in the vicinity of a plane $(x,y)$ and subject to a strong uniform magnetic field in the plane of the gas. The coupled effects of the confinement and of the magnetic field induce fast oscillations in time that need to

Sourish Dutta, Robert J. Scherrer

We examine dark energy models in which a phantom field $ϕ$ is rolling near a local minimum of its potential $V(ϕ)$.We require that $(1/V)(dV/dϕ) \ll 1$, but $(1/V)(d^2 V/dϕ^2)$ can be large. Using techniques developed in the context of hilltop quintessence, we derive a general expression for $w$ as a function of the scale factor, and as in the hilltop case,

Mathieu Stienon

Hypercomplex structures on Courant algebroids unify holomorphic symplectic structures and usual hypercomplex structures. In this note, we prove the equivalence of two characterizations of hypercomplex structures on Courant algebroids, one in terms of Nijenhuis concomitants and the other in terms of (almost) torsionfree connections for which each of the three

Geoffrey Compère, Keiju Murata, Tatsuma Nishioka

The Kerr/CFT correspondence has been recently broadened to the general extremal black holes under the assumption that the central charges from the non-gravitational fields vanish. To confirm this proposal, we derive the expression of the conserved charges in the Einstein-Maxwell-scalar theory with topological terms in four and five dimensions and check that

O. Vega, M. S. Clemens, A. Bressan, G. L. Granato

We fit the near-infrared to radio spectral energy distributions of a sample of 30 luminous and ultra-luminous infrared galaxies with models that include both starburst and AGN components. The aim of the work was to determine important physical parameters for this kind of objects such as the optical depth towards the luminosity source, the star formation rate

Qiang Zhen, Charles Knessl

We consider the $M/M/1$-PS queue with processor sharing. We study the conditional sojourn time distribution of an arriving customer, conditioned on the number of other customers present. A new formula is obtained for the conditional sojourn time distribution, using a discrete Green&#39;s function. This is shown to be equivalent to some classic results of Pol

Qiang Zhen, Charles Knessl

We consider the $M/G/1$ queue with a processor sharing server. We study the conditional sojourn time distribution, conditioned on the customer&#39;s service requirement, as well as the unconditional distribution, in various asymptotic limits. These include large time and/or large service request, and heavy traffic, where the arrival rate is only slightly les

Carla Farsi, Christopher Seaton

We introduce the $Γ$-Euler-Satake characteristics of a general orbifold $Q$ presented by an orbifold groupoid $\mathcal{G}$, generalizing to orbifolds that are not necessarily global quotients the generalized orbifold Euler characteristics of Bryan-Fulman and Tamanoi. Each of these Euler characteristics is defined as the Euler-Satake characteristic of the sp

Johan Chang, Erik Johnson, Takamichi Sakai, Hiroyasu Saka

We have investigated the melting of nano-sized cone shaped aluminium needles coated with amorphous carbon using transmission electron microscopy. The interface between solid and liquid aluminium was found to have spherical topology. For needles with fixed apex angle, the depressed melting temperature of this spherical interface, with radius $R$, was found to

Carla Farsi, Christopher Seaton

For a finitely generated discrete group $Γ$, the $Γ$-sectors of an orbifold $Q$ are a disjoint union of orbifolds corresponding to homomorphisms from $Γ$ into a groupoid presenting $Q$. Here, we show that the inertia orbifold and $k$-multi-sectors are special cases of the $Γ$-sectors, and that the $Γ$-sectors are orbifold covers of Leida&#39;s fixed-point se

Igor Burstyn

This article is a response to an off-the-record discussion that I had at an international meeting of epidemiologists. It centered on a concern, perhaps widely spread, that measurement error adjustment methods can induce positive bias in results of epidemiological studies when there is no true association. I trace the possible history of this supposition and

J. Chang, N. B. Christensen, Ch. Niedermayer, K. Lefmann

Inelastic neutron-scattering experiments on the high-temperature superconductor La$_{1.855}$Sr$_{0.145}$CuO$_{4}$ reveal a magnetic excitation gap $Δ$ that decreases continuously upon application of a magnetic field perpendicular to the CuO$_2$ planes. The gap vanishes at the critical field required to induce long-range incommensurate antiferromagnetic order

H. Shakeripour, M. A. Tanatar, C. Petrovic, Louis Taillefer

The symmetry of the order parameter is the defining property of a superconductor and a strong clue to its pairing mechanism. While d-wave symmetry is firmly established in high-Tc superconductors, in no heavy-fermion superconductor is the symmetry known definitively. One way to elucidate the order parameter is to locate the symmetry-imposed nodes in the ener

Heinz H. Bauschke, Xianfu Wang, Liangjin Yao

The question whether or not the sum of two maximal monotone operators is maximal monotone under Rockafellar&#39;s constraint qualification - that is, whether or not &#34;the sum theorem&#34; is true - is the most famous open problem in Monotone Operator Theory. In his 2008 monograph &#34;From Hahn-Banach to Monotonicity&#34;, Stephen Simons asked whether or

Kevin Bundy, Masataka Fukugita, Richard S. Ellis, Thomas A. Targett

Using deep infrared observations conducted with the MOIRCS on the Subaru Telescope in GOODS-N combined with public surveys in GOODS-S, we investigate the dependence on stellar mass, M_*, and galaxy type of the close pair fraction (5 kpc < r < 20 kpc) and implied merger rate. In common with some recent studies we find that the fraction of paired systems that

R. E. Mason, N. A. Levenson, Y. Shi, C. Packham

The unified model of active galactic nuclei (AGN) predicts silicate emission features at 10 and 18 microns in type 1 AGN, and such features have now been observed in objects ranging from distant QSOs to nearby LINERs. More surprising, however, is the detection of silicate emission in a few type 2 AGN. By combining Gemini and Spitzer mid-infrared imaging and

Sourav Sur

We examine the plausibility of crossing the cosmological constant ($Ł$) barrier in a two-field quintessence model of dark energy, involving a kinetic interaction between the individual fields. Such a kinetic interaction may have its origin in the four dimensional effective two-field version of the Dirac-Born-Infeld action, that describes the motion of a D3-b

Raji Heyrovska

The Golden ratio which appears in the geometry of a variety of creations in Nature is found to arise right in the Bohr radius of the hydrogen atom due to the opposite charges of the electron and proton. The bond length of the hydrogen molecule is the diagonal of a square on the Bohr radius and hence also has two Golden sections, which form the cationic and a

R. Karoui, V. V. Vershinin

Pure braid groups and pure mapping class groups of a punctured sphere have many features in common. In the paper the graded Lie algebra of the descending central series of the pure mapping class of a sphere is studied. A simple presentation of this Lie algebra is obtained.

Olivier Durand de Gévigney, Frédéric Meunier, Christian Popa, Julien Reygner

In the present paper, we study algorithmic questions for the arc-intersection graph of directed paths on a tree. Such graphs are known to be perfect (proved by Monma and Wei in 1986). We present faster algorithms than all previously known algorithms for solving the minimum coloring and the minimum clique cover problems. They both run in $O(np)$ time, where $

Greg W Anderson, Dinesh S Thakur

We provide a period interpretation for multizeta values (in the function field context) in terms of explicit iterated extensions of tensor powers of Carlitz motives (mixed Carlitz-Tate t-motives). We give examples of combinatorially involved relations that these multizeta values satisfy.

R. Karoui, V. V. Vershinin

Braid groups and mapping class groups have many features in common. Similarly to the notion of inverse braid monoid inverse mapping class monoid is defined. It concerns surfaces with punctures, but among given $n$ punctures several can be omitted. This corresponds to braids where the number of strings is not fixed. In the paper we give the analogue of the De

M. C. Gonzalez-Garcia, Francis Halzen, Soumya Mohapatra

We perform a realistic evaluation of the potential of IceCube, a kilometer-scale neutrino detector under construction at the South Pole, to detect neutrinos in the direction of the potential accelerators of the Galactic cosmic rays. We take fully account of the fact that the measurement of the energy of the secondary muons can be used to further discriminate