arXiv papers from May 2010

Peter Ruckdeschel

We consider estimation of a one-dimensional location parameter by means of M-estimators S_n with monotone influence curve psi. For growing sample size n, on suitably thinned out convex contamination ball BQ_n of shrinking radius r/sqrt(n) about the ideal distribution, we obtain an expansion of the asymptotic maximal mean squared error MSE of form r^2 sup psi

Gilad Gour, Nolan R. Wallach

We find an operational interpretation for the 4-tangle as a type of residual entanglement, somewhat similar to the interpretation of the 3-tangle. Using this remarkable interpretation, we are able to find the class of maximally entangled four-qubits states which is characterized by four real parameters. The states in the class are maximally entangled in the

Donald Marolf, Ian A. Morrison

We compute 1-loop corrections to Lorentz-signature de Sitter-invariant 2-point functions defined by the interacting Euclidean vacuum for massive scalar quantum fields with cubic and quartic interactions. Our results apply to all masses for which the free Euclidean de Sitter vacuum is well-defined, including values in both the complimentary and the principal

V. S. Ptuskin, V. N. Zirakashvili, E. S. Seo

The spectra of high-energy protons and nuclei accelerated by supernova remnant shocks are calculated taking into account magnetic field amplification and Alfvenic drift both upstream and downstream of the shock for different types of supernova remnants during their evolution. The maximum energy of accelerated particles may reach $5\cdot10^{18}$ eV for Fe ion

Jonathas Nunes da Silva, Evy Salcedo, Alan Barros de Oliveira, Marcia C. Barbosa

Using molecular dynamic simulations we study a system of particles interacting through a continuous core-softened potentials consisting of a hard core, a shoulder at closest distances and an attractive well at further distance. We obtain the pressure-temperature phase diagram of of this system for various depths of the tunable attractive well. Since this is

Dastgeer Shaikh, B Dasgupta

We have developed an analytic model to describe coupling of plasma and neutral fluids in the partially ionized heliosphere plasma medium. The sources employed in our analytic model are based on a $\kappa$-distribution as opposed to the Maxwellian distribution function. Our model uses the $\kappa$-distribution to analytically model the energetic neutral atoms

Christos A. Koutsos, Nikolitsa I. Yannopoulou, Petros E. Zimourtopoulos

This paper introduces the FLOSS Free Libre Open Source Software [VEMSA3D], a contraction of "Visual Electromagnetic Simulator for 3D Antennas", which are geometrically modeled, either exactly or approximately, as thin wire polygonal structures; presents its GUI Graphical User Interface capabilities, in interactive mode and/or in handling suitable formed ante

Marco Gaboardi, Jean-Yves Marion, Simona Ronchi Della Rocca

We present a type system for an extension of lambda calculus with a conditional construction, named STAB, that characterizes the PSPACE class. This system is obtained by extending STA, a type assignment for lambda-calculus inspired by Lafont's Soft Linear Logic and characterizing the PTIME class. We extend STA by means of a ground type and terms for booleans

Krzysztof Dębicki, Kamil Marcin Kosiński, Michel Mandjes, Tomasz Rolski

This paper considers extreme values attained by a centered, multidimensional Gaussian process $X(t)= (X_1(t),\ldots,X_n(t))$ minus drift $d(t)=(d_1(t),\ldots,d_n(t))$, on an arbitrary set $T$. Under mild regularity conditions, we establish the asymptotics of \[\log\mathbb P\left(\exists{t\in T}:\bigcap_{i=1}^n\left\{X_i(t)-d_i(t)>q_iu\right\}\right),\] for p

T. Lanting, R. Harris, J. Johansson, M. H. S. Amin

We report measurements of macroscopic resonant tunneling between the two lowest energy states of a pair of magnetically coupled rf-SQUID flux qubits. This technique provides a direct means of observing two-qubit dynamics and a probe of the environment coupled to the pair of qubits. Measurements of the tunneling rate as a function of qubit flux bias show a Ga

Ruthi Hortsch, Igor Kriz, Ales Pultr

We characterize vertex algebras (in a suitable sense) as algebras over a certain graded co-operad. We also discuss some examples and categorical implications of this characterization.

Sa'ar Hersonsky

In this paper we continue the study started in part I (posted). We consider a planar, bounded, $m$-connected region $\Omega$, and let $\bord\Omega$ be its boundary. Let $\mathcal{T}$ be a cellular decomposition of $\Omega\cup\bord\Omega$, where each 2-cell is either a triangle or a quadrilateral. From these data and a conductance function we construct a cano

Sofia Sivertsson, Paolo Gondolo

The first stars to form in the universe may have been dark stars, powered by dark matter annihilation instead of nuclear fusion. The initial amount of dark matter gathered by the star gravitationally can sustain it only for a limited period of time. It has been suggested that capture of additional dark matter from the environment can prolong the dark star ph

M. Chichignoud

The paper deals with the non-parametric estimation in the regression with the multiplicative noise. Using the local polynomial fitting and the bayesian approach, we construct the minimax on isotropic H\"older class estimator. Next applying Lepski's method, we propose the estimator which is optimally adaptive over the collection of isotropic H\"older classes.

Bruce P. Ayati, Isaac Klapper

We present models of dormancy in a planktonic culture and in biofilm, and examine the relative advantage of short dormancy versus long dormancy times in each case. Simulations and analyses indicate that in planktonic batch cultures and in chemostats, live biomass is maximized by the fastest possible exit from dormancy. The lower limit of time to reawakening

Antígona Segura, Lucianne Walkowicz, Victoria Meadows, James Kasting

Main sequence M stars pose an interesting problem for astrobiology: their abundance in our galaxy makes them likely targets in the hunt for habitable planets, but their strong chromospheric activity produces high energy radiation and charged particles that may be detrimental to life. We studied the impact of the 1985 April 12 flare from the M dwarf, AD Leoni

Jesus Zendejas, Antigona Segura, Alejandro Raga

We present an analytic model for the interaction between planetary atmospheres and stellar winds from main sequence M stars, with the purpose of obtaining a quick test-model that estimates the timescale for total atmospheric mass loss due to this interaction. Planets in the habitable zone of M dwarfs may be tidally locked and may have weak magnetic fields, b

Abhijit Gadde, Elli Pomoni, Leonardo Rastelli

In this paper we find preliminary evidence that N=2 superconformal QCD, the SU(N_c) SYM theory with N_f= 2 N_c fundamental hypermultiplets, might be integrable in the large N Veneziano limit. We evaluate the one-loop dilation operator in the scalar sector of the N=2 superconformal quiver with SU(N_c) X SU(N_{\check c}) gauge group, for N_c = N_{\check c}. Bo

Mustapha Ishak, Wolfgang Rindler

This review surveys some recent developments concerning the effect of the cosmological constant on the bending of light by a spherical mass in Kottler (Schwarzchild-de Sitter) spacetime. Some proposals of how such an effect may be put into a setting of gravitational lensing in cosmology are also discussed. The picture that emerges from this review is that it

D. Mogilevtsev, F. A. Pinheiro, R. R. dos Santos, S. B. Cavalcanti

Light propagation through 1D disordered structures composed of alternating layers, with random thicknesses, of air and a dispersive metamaterial is theoretically investigated. Both normal and oblique incidences are considered. By means of numerical simulations and an analytical theory, we have established that Anderson localization of light may be suppressed

Matthew S. Foster, Emil A. Yuzbashyan, Boris L. Altshuler

We study a quantum quench in a 1D system possessing Luttinger liquid (LL) and Mott insulating ground states before and after the quench, respectively. We show that the quench induces power law amplification in time of any particle density inhomogeneity in the initial LL ground state. The scaling exponent is set by the fractionalization of the LL quasiparticl

Iman Setayesh

Let $D$ be a smooth divisor on a non singular surface $S$. We compute Betti numbers of the relative Hilbert scheme of points of $S$ relative to $D$. In the case of $\PP^2$ and a line in it, we give an explicit set of generators and relations for the cohomology groups of this space.

J. Terasaki, J. Engel

We describe a new implementation of the quasiparticle random phase approximation (QRPA) in axially-symmetric deformed nuclei with Skyrme and volume-pairing energy-density functionals. After using a variety of tests to demonstrate the accuracy of the code in ^{24,26}Mg and ^{16}O, we report the first fully self-consistent application of the Skyrme QRPA to a h

Hilma Vasconcelos, Liliana Sanz, Scott Glancy

Both discrete and continuous systems can be used to encode quantum information. Most quantum computation schemes propose encoding qubits in two-level systems, such as a two-level atom or an electron spin. Others exploit the use of an infinite-dimensional system, such as a harmonic oscillator. In "Encoding a qubit in an oscillator" [Phys. Rev. A 64 012310 (20

Giovanni Amelino-Camelia, Antonino Marciano, Marco Matassa, Giacomo Rosati

Observations of gamma-ray bursts are being used to test for a momentum dependence of the speed of photons, partly motivated by preliminary results reported in analyses of some quantum-spacetime scenarios. The relationship between time of arrival, momentum of the photon and redshift of the source which is used for these purposes assumes a "breakdown" of relat

Steven S. Gubser

I explain a generalization of Bjorken flow where the medium has finite transverse size and expands both radially and along the beam axis. If one assumes that the equations of viscous hydrodynamics can be used, with p=epsilon/3 and zero bulk viscosity, then the flow I describe can be developed into an exact solution of the relativistic Navier-Stokes equations

Boyke Rochau, Wolfgang Brandner, Andrea Stolte, Mario Gennaro

We have analyzed two epochs of HST/WFPC2 observations of the young Galactic starburst cluster in NGC 3603 with the aim to study its internal dynamics and stellar population. Relative proper motions measured over 10.15 yrs of more than 800 stars enable us to distinguish cluster members from field stars. The best-fitting isochrone yields Av=4.6-4.7 mag, a dist

O. K. Madej, P. G. Jonker, A. C. Fabian, C. Pinto

Ultra-compact X-ray binaries consist of a neutron star or black hole that accretes material from a white dwarf-donor star. The ultra-compact nature is expressed in very short orbital periods of less than 1 hour. In the case of 4U 0614+091 oxygen-rich material from a CO or ONe white dwarf is flowing to the neutron star. This oxygen-rich disc can reflect X-ray

Johannes Haller, Gfitter group

The global electroweak fit of the Standard Model (SM) with Gfitter can be used to constrain yet unknown SM parameters, such as the Higgs mass, but also physics beyond the SM (BSM) via the formalism of oblique parameters. This paper presents updated results of the Gfitter SM fit using the latest available electroweak precision measurements and the recent comb

Georg G. Raffelt, Irene Tamborra

We study collective oscillations of a two-flavor neutrino system with arbitrary but fixed density. In the vacuum limit, modes with different energies quickly de-phase (kinematical decoherence), whereas in the limit of infinite density they lock to each other (synchronization). For intermediate densities, we find different classes of solutions. There is alway

Bence Kocsis, Scott Tremaine

Observations of the spatial distribution and kinematics of young stars in the Galactic centre can be interpreted as showing that the stars occupy one, or possibly two, discs of radii ~0.05-0.5 pc. The most prominent (`clockwise') disc exhibits a strong warp: the normals to the mean orbital planes in the inner and outer third of the disc differ by ~60 deg. Us

Michael I. Eides, Timothy J. S. Martin

The leading relativistic and recoil corrections to bound state $g$-factors of particles with arbitrary spin are calculated. It is shown that these corrections are universal for any spin and depend only on the free particle gyromagnetic ratios. To prove this universality we develop NRQED for charged particles with an arbitrary spin. The coefficients in the NR

David Callan

Hexaflexagons were popularized by the late Martin Gardner in his first Scientific American column in 1956. Oakley and Wisner showed that they can be represented abstractly by certain recursively defined permutations called pats, and deduced that they are counted by the Catalan numbers. Counting pats by number of descents yields the curious identity Sum[1/(2n

Ching-Ming Chen, Johanna Knapp, Maximilian Kreuzer, Christoph Mayrhofer

Making use of toric geometry we construct a class of global F-theory GUT models. The base manifolds are blowups of Fano threefolds and the Calabi-Yau fourfold is a complete intersection of two hypersurfaces. We identify possible GUT divisors and construct SO(10) models on them using the spectral cover construction. We use a split spectral cover to generate c

Ralf Koetter, Jun Ma, Alexander Vardy

The main computational steps in algebraic soft-decoding, as well as Sudan-type list-decoding, of Reed-Solomon codes are bivariate polynomial interpolation and factorization. We introduce a computational technique, based upon re-encoding and coordinate transformation, that significantly reduces the complexity of the bivariate interpolation procedure. This re-

Carlos Gershenson

Random Boolean networks (RBNs) are models of genetic regulatory networks. It is useful to describe RBNs as self-organizing systems to study how changes in the nodes and connections affect the global network dynamics. This article reviews eight different methods for guiding the self-organization of RBNs. In particular, the article is focussed on guiding RBNs

Foto Afrati, Victor Kyritsis, Paraskevas V. Lekeas, Dora Souliou

Different types of data skew can result in load imbalance in the context of parallel joins under the shared nothing architecture. We study one important type of skew, join product skew (JPS). A static approach based on frequency classes is proposed which takes for granted the data distribution of join attribute values. It comes from the observation that the

Felipe Mondaini, L. Moriconi

We solve the Chapman-Kolmogorov equation and study the exact splitting probabilities of the general stochastic process which describes polymer translocation through membrane pores within the broad class of Markov chains. Transition probabilities which satisfy a specific balance constraint provide a refinement of the Chuang-Kantor-Kardar relaxation picture of

Rafael A. Porto

Using effective field theory (EFT) techniques we calculate the next-to-leading order (NLO) spin-orbit contributions to the gravitational potential of inspiralling compact binaries. We use the covariant spin supplementarity condition (SSC), and explicitly prove the equivalence with previous results by Faye et al. in arXiv:gr-qc/0605139. We also show that the

David M. South

New measurements of neutral and charged current cross sections at large negative four-momentum transfer squared Q^2 have been performed by H1 and ZEUS, using up to the complete HERA II ep data, which was taken with polarised electron and positron beams. The data are compared to predictions of the Standard Model, based on various parton distribution function

Ching-Ming Chen, Yu-Chieh Chung

In this paper we construct supersymmetric flipped SU(5) GUTs from E_8 singularities in F-theory. We start from an SO(10) singularity unfolded from an E_8 singularity by using an SU(4) spectral cover. To obtain realistic models, we consider (3,1) and (2,2) factorizations of the SU(4) cover. After turning on the massless U(1)_X gauge flux, we obtain the SU(5)

R. Sekhar Chivukula, Elizabeth H. Simmons

Since the pioneering work of Eichten and Lane it has been known that the scale of the interactions responsible for the generation of the strange-quark mass in extended technicolor theories must, absent any "GIM-like" mechanism for suppressing flavor-changing neutral currents, be greater than of order 1000 TeV. In this note we point out that the constraint fr

Rolf Gohm, Claus Köstler

We provide an operator algebraic proof of a classical theorem of Thoma which characterizes the extremal characters of the infinite symmetric group $\mathbb{S}_\infty$. Our methods are based on noncommutative conditional independence emerging from exchangeability and we reinterpret Thoma's theorem as a noncommutative de Finetti type result. Our approach is, i

Eva Viehmann

We generalize purity of the Newton stratification to purity for a single break point of the Newton point in the context of local G-shtukas respectively of elements of the loop group of a reductive group. As an application we prove that elements of the loop group bounded by a given dominant coweight satisfy a generalization of Grothendieck's conjecture on def

Aveek Bid, Nissim Ofek, Hiroyuki Inoue, Moty Heiblum

In the quantum Hall effect regime, taking place in a two-dimensional-electron gas under strong magnetic field, currents flow along the edges of the sample. For some particle-hole conjugate states of the fractional regime, e.g., with filling between 1/2 and 1 of the lowest Landau level; early predictions suggested the presence of counter-propagating edge curr

Harald Grosse, Peter Prešnajder, Zhituo Wang

We present an oscillator realization of discrete series representations of group SU(2,2). We give formulas for the coherent state star-product quantization of a Bergman domain $D$. A formulation of a (regularized) non-commutative scalar field on a quantized $D$ is given.

Carlos Campos-Apanco, Andrés Pedroza

We prove the bounded isometry conjecture of F. Lalonde and L. Polterovich for a special class of closed symplectic manifolds. As a byproduct, it is shown that the flux group of a product of these special symplectic manifold is isomorphic to the direct sum of the flux group of each symplectic manifold.

Vitaly Vanchurin

We develop a model of string dynamics with back-reaction from both scaling and non-scaling loops taken into account. The evolution of a string network is described by the distribution functions of coherence segments and kinks. We derive two non-linear equations which govern the evolution of the two distributions and solve them analytically in the limit of la

J. C. Morales, J. Gallardo, I. Ribas, C. Jordi

In recent years, analyses of eclipsing binary systems have unveiled differences between the observed fundamental properties of low-mass stars and those predicted by stellar structure models. Particularly, radius and effective temperatures computed from models are ~ 5-10% lower and ~ 3-5% higher than observed, respectively. These discrepancies have been attri

Kurt Lechner

We find that the conjectured heterotic SO(32) five-brane sigma model develops necessarily k-anomalies, and we investigate their form. We show that these anomalies can be absorbed by modifications of the superspace constraints, that satisfy automatically the modified Bianchi-identity $dH_7=X_8$ of N=1, D=10 supergravity. The k-anomalies induce in particular a

Nestor Caticha, Renato Vicente

Moral Foundation Theory states that groups of different observers may rely on partially dissimilar sets of moral foundations, thereby reaching different moral valuations. The use of functional imaging techniques has revealed a spectrum of cognitive styles with respect to the differential handling of novel or corroborating information that is correlated to po

Jari Hyväluoma, Christian Kunert, Jens Harting

On microstructured hydrophobic surfaces, geometrical patterns may lead to the appearance of a superhydrophobic state, where gas bubbles at the surface can have a strong impact on the fluid flow along such surfaces. In particular, they can strongly influence a detected slip at the surface. We present two-phase lattice Boltzmann simulations of a flow over stru

Choongbum Lee, Wojciech Samotij

An $n$-vertex graph is called pancyclic if it contains a cycle of length $t$ for all $3 \leq t \leq n$. In this paper, we study pancyclicity of random graphs in the context of resilience, and prove that if $p \gg n^{-1/2}$, then the random graph $G(n,p)$ a.a.s. satisfies the following property: Every Hamiltonian subgraph of $G(n,p)$ with more than $(1/2 + o(

A. Alexandrov

We derive exact matrix integral representations for different sums over partitions. The characteristic feature of all obtained matrix models is the presence of logarithmic (or, vice versa, exponential) terms in the potential. Our derivation is based on the application of the higher Casimir operators. The Toda lattice integrability of the basic sums over part

Sumanta Bhandary, Mikhail I. Katsnelson, Olle Eriksson, Biplab Sanyal

We have performed density functional calculations as well as employed a tight-binding theory, to study the effect of passivation of zigzag graphene nanoribbons (ZGNR) by Hydrogen. We show that each edge C atom bonded with 2 H atoms open up a gap and destroys magnetism for small widths of the nanoribbon. However, a re-entrant magnetism accompanied by a metall

Humberto Hijar, J. G. Mendez-Bermudez, I. Santamaria-Holek

Mesoscopic non-equilibrium thermodynamics is used to formulate a model describing non-homogeneous and non-Debye dielectric relaxation. The model is presented in terms of a Fokker-Planck equation for the probability distribution of non-interacting polar molecules in contact with a heat bath and in the presence of an external time-dependent electric field. Mem

Marco Taoso, Fabio Iocco, Georges Meynet, Gianfranco Bertone

We study the effect of dark matter (DM) particles in the Sun, focusing in particular on the possible reduction of the solar neutrinos flux due to the energy carried away by DM particles from the innermost regions of the Sun, and to the consequent reduction of the temperature of the solar core. We find that in the very low-mass range between 4 and 10 GeV, rec

Marco Azzaro, Santiago Becerril, Cristian Vilar, Xabier Arrillaga

Fiber-fed spectrographs dedicated to observing massive portions of the sky are increasingly being more demanded within the astronomical community. For all the fiber-fed instruments, the primordial and common problem is the positioning of the fiber ends, which must match the position of the objects of a target field on the sky. Amongst the different approache

R. V. Mishmash, L. D. Carr

We reply to Jacek Dziarmaga, Piotr Deuar, and Krzysztof Sacha's comment, arXiv:1001.1045, supporting the authors' simulations but differentiating between near-mean-field and strongly quantum regimes. We clarify that we have three lines of evidence on decay of dark solitons and connect our work to Lieb's Type-II excitations and the true meaning of a quantum d

P. Kant, R. V. Harlander, L. Mihaila, M. Steinhauser

The light CP even Higgs boson mass, Mh, is calculated to three-loop accuracy within the Minimal Supersymmetric Standard Model (MSSM). The result is expressed in terms of DRbar parameters and implemented in the computer program H3m. The calculation is based on the proper approximations and their combination in various regions of the parameter space. The three

Piyali Chatterjee, Axel Brandenburg, Gustavo Guerrero

The small-scale magnetic helicity produced as a by-product of the large-scale dynamo is believed to play a major role in dynamo saturation. In a mean-field model the generation of small-scale magnetic helicity can be modelled by using the dynamical quenching formalism. Catastrophic quenching refers to a decrease of the saturation field strength with increasi

I. Santamaria-Holek, Carlos I. Mendoza

We propose an improved effective-medium theory to obtain the concentration dependence of the viscosity of particle suspensions at arbitrary volume fractions. Our methodology can be applied, in principle, to any particle shape as long as the intrinsic viscosity is known in the dilute limit and the particles are not too elongated. The procedure allows to const

Carolin B. Braeuninger, Alejandro Ibarra, Cristoforo Simonetto

The most general two Higgs doublet model contains new sources of flavour violation that are usually in conflict with the experimental constraints. One possibility to suppress the exotic contribution to the flavour changing neutral currents consists on imposing the alignment of the Yukawa couplings. This condition presumably holds at a high-energy scale and i

Alexander Gnedin, Alexander Iksanov, Alexander Marynych

The Bernoulli sieve is a version of the classical balls-in-boxes occupancy scheme, in which random frequencies of infinitely many boxes are produced by a multiplicative random walk, also known as the residual allocation model or stick-breaking. We give an overview of the limit theorems concerning the number of boxes occupied by some balls out of the first $n

S. Rulands, T. Reichenbach, E. Frey

Species extinction occurs regularly and unavoidably in ecological systems. The time scales for extinction can broadly vary and inform on the ecosystem's stability. We study the spatio-temporal extinction dynamics of a paradigmatic population model where three species exhibit cyclic competition. The cyclic dynamics reflects the non-equilibrium nature of the s

Ivan P. Levkivskyi, Juerg Froehlich, Eugene V. Sukhorukov

Interference of fractionally charged quasi-particles is expected to lead to Aharonov-Bohm oscillations with periods larger than the flux quantum. However, according to the Byers-Yang theorem, observables of an electronic system are invariant under an adiabatic insertion of a quantum of singular flux. We resolve this seeming paradox by considering a microscop

Inna, Capdeboscq, Anne Thomas

Let G be a topological Kac-Moody group of rank 2 with symmetric Cartan matrix, defined over a finite field F_q. An example is G = SL(2,F_q((t^{-1}))). We determine a positive lower bound on the covolumes of cocompact lattices in G, and construct a cocompact lattice \Gamma_0 < G which realises this minimum. This completes the work begun in Part I, which consi

Noam Soker, Yohai Meiron

We use a recent sample of 49 galaxies to show that there is a proportionality relation between the black hole mass M_BH and the quantity \mu =M_G*\sigma /c, where M_G is mass of the spheroidal stellar component and \sigma is the stellar velocity dispersion. \mu is called the momentum parameter and the ratio is M_BH/\mu ~3.3. This result is applied to the pen

Axel Brandenburg, Koen Kemel, Nathan Kleeorin, Igor Rogachevskii

To understand the basic mechanism of the formation of magnetic flux concentrations, we determine by direct numerical simulations the turbulence contributions to the mean magnetic pressure in a strongly stratified isothermal layer with large plasma beta, where a weak uniform horizontal mean magnetic field is applied. The negative contribution of turbulence to

Denis Gonzalez, Andreas Reisenegger

Context: The standard cooling models of neutron stars predict temperatures $T<10^{4}$ K for ages $t>10^{7}$ yr. However, the likely thermal emission detected from the millisecond pulsar J0437-4715, of spin-down age $t_s \sim 7\times10^9$ yr, implies a temperature $T\sim 10^5$ K. Thus, a heating mechanism needs to be added to the cooling models in order to ob

Curtis Menton

We study the behavior of Range Voting and Normalized Range Voting with respect to electoral control. Electoral control encompasses attempts from an election chair to alter the structure of an election in order to change the outcome. We show that a voting system resists a case of control by proving that performing that case of control is computationally infea

Alexander Jung, Zvika Ben-Haim, Franz Hlawatsch, Yonina C. Eldar

We consider unbiased estimation of a sparse nonrandom vector corrupted by additive white Gaussian noise. We show that while there are infinitely many unbiased estimators for this problem, none of them has uniformly minimum variance. Therefore, we focus on locally minimum variance unbiased (LMVU) estimators. We derive simple closed-form lower and upper bounds

Michael Damron, Artëm Sapozhnikov

We prove limit theorems and variance estimates for quantities related to ponds and outlets for 2D invasion percolation. We first exhibit several properties of a sequence $({\mathbf{O}}(n))$ of outlet variables, the $n$th of which gives the number of outlets in the box centered at the origin of side length $2^n$. The most important of these properties describ

M. I. Vysotsky

The photon polarization operator in superstrong magnetic fields induces the dynamical photon "mass" which leads to screening of Coulomb potential at small distances $z\ll 1/m$, $m$ is the mass of an electron. We demonstrate that this behaviour is qualitatively different from the case of D=2 QED, where the same formula for a polarization operator leads to scr

Bernardo Cascales, Ondřej F. K. Kalenda, Jiří Spurný

We introduce two measures of weak non-compactness $Ja_E$ and $Ja$ that quantify, via distances, the idea of boundary behind James' compactness theorem. These measures tell us, for a bounded subset $C$ of a Banach space $E$ and for given $x^*\in E^*$, how far from $E$ or $C$ one needs to go to find $x^{**}\in \bar{C}^{w^*}\subset E^{**}$ with $x^{**}(x^*)=\su

Michael B. Marcus, Jay Rosen

We provide a sufficient condition for the continuity of real valued permanental processes. When applied to the subclass of permanental processes which consists of squares of Gaussian processes, we obtain the sufficient condition for continuity which is also known to be necessary. Using an isomorphism theorem of Eisenbaum and Kaspi which relates Markov local

P. Kh. Atanasova, T. L. Boyadjiev, Yu. M. Shukrinov, E. V. Zemlyanaya

We study the long Josephson junction (LJJ) model which takes into account the second harmonic of the Fourier expansion of Josephson current. The sign of second harmonic is important for many physical applications. The influence of the sign and value of the second harmonic on the magnetic flux distributions is investigated. At each step of numerical continuat

Birger Horstmann, Stephan Dürr, Tommaso Roscilde

We propose a novel realization of Anderson localization in non-equilibrium states of ultracold atoms trapped in state-dependent optical lattices. The disorder potential leading to localization is generated with a Rabi pulse transfering a fraction of the atoms into a different internal state for which tunneling between lattice sites is suppressed. Atoms with

I. Malfanti, A. Taschin, P. Bartolini, B. Bonello

We present heterodyne detected transient grating (HD-TG) measurements on 1D surface corrugated Phononic Crystal (PC) with characteristic band edge wave vector of $\pi/5$ $\mu$m$^{-1}$. This experimental investigation enables both the direct band diagram characterization of surface waves and a direct measurement of the group velocity dispersion. The experimen

Tomasz L. Partyka

We consider how does the introduction of a Polyakov loop affects the spatially inhomogeneous quark condensate. The primary result of our work is that the existence of the spatially non-uniform chiral phase is confirmed within the Polyakov NJL model in a chiral limit. These findings are obtained both in a 3d-cutoff and in a Schwinger (proper time) regularizat

Pierre-Emmanuel Caprace, Michah Sageev

We prove that any group acting essentially without a fixed point at infinity on an irreducible finite-dimensional CAT(0) cube complex contains a rank one isometry. This implies that the Rank Rigidity Conjecture holds for CAT(0) cube complexes. We derive a number of other consequences for CAT(0) cube complexes, including a purely geometric proof of the Tits A

Mathieu Pierre, Romain Wacquez, Benoit Roche, Xavier Jehl

We report electronic transport on silicon double and triple dots created with the optimized number of two gates. Using silicon nitride spacers two dots in series are created below two top gates overlapping a silicon nanowire. Coupling between dots is controlled by gate voltages. A third dot is created either by combined action of gate voltages or local dopin

Ana Romero, Francis Sergeraert

We show in this text how the most important homology equivalences of fundamental Algebraic Topology can be obtained as reductions associated to discrete vector fields. Mainly the homology equivalences whose existence -- most often non-constructive -- is proved by the main spectral sequences, the Serre and Eilenberg-Moore spectral sequences. On the contrary,

Georges Grunberg

The modified evolution equation for parton distributions of Dokshitzer, Marchesini and Salam is extended to non-singlet Deep Inelastic Scattering coefficient functions and the physical evolution kernels which govern their scaling violation. Considering the x->1 limit, it is found that the leading next-to-eikonal logarithmic contributions to the momentum spac

Pere Masjuan

We discuss some topics concerning rational approximations in Quantum Chromodynamics, especially those related with the mathematical theory of Pad\'e Approximants. We focus on two kind of problems: the first one related with meromorphic functions (inspired by the Large-Nc limit in QCD) where we explore the Minimal Hadronic Approximation through the extraction

Mohammad Mansouryar

There are two main approaches to generate the negative energy density (NED) in the literature. The Casimir effect and the squeezed vacuum. The possibility of the latter approach is qualitatively reviewed in this paper. It is proposed that the soliton theory may give remarkable contributions to generate and separate the NED out of the quantum vacuum. By apply

Luigi Amico, Holger Frahm, Andreas Osterloh, Tobias Wirth

We formulate the functional Bethe ansatz for bosonic (infinite dimensional) representations of the Yang-Baxter algebra. The main deviation from the standard approach consists in a half infinite 'Sklyanin lattice' made of the eigenvalues of the operator zeros of the Bethe annihilation operator. By a separation of variables, functional TQ equations are obtaine

Melchior Grutzmann

We define a new kind of algebroid which fulfills a Leibniz rule, a Jacobi identity twisted by a 3-form $H$ with values in the kernel of the anchor map, and the twist is closed under a naturally occurring exterior covariant derivative. We give examples and define three kinds of cohomology two via realization as Q-structure on graded manifolds. This classifies

Yousef Bisabr

The $f(R)$ gravity models formulated in Einstein conformal frame are equivalent to Einstein gravity together with a minimally coupled scalar field. We shall explore phantom behavior of $f(R)$ models in this frame and compare the results with those of the usual notion of phantom scalar field.

P. Santini, R. Maiolino, B. Magnelli, L. Silva

We use deep observations taken with the Photodetector Array Camera and Spectrometer (PACS), on board the Herschel satellite as part of the PACS evolutionary probe (PEP) guaranteed project along with submm ground-based observations to measure the dust mass of a sample of high-z submillimeter galaxies (SMGs). We investigate their dust content relative to their

Giovanni Samaey, Tony Lelievre, Vincent Legat

We propose a numerical procedure to study closure approximations for FENE dumbbells in terms of chosen macroscopic state variables, enabling to test straightforwardly which macroscopic state variables should be included to build good closures. The method involves the reconstruction of a polymer distribution related to the conditional equilibrium of a microsc

S. Dusari, J. Barzola-Quiquia And P. Esquinazi

We have studied the magnetoresistance (MR) of thin highly oriented pyrolytic graphite mesoscopic samples without and with micro-constrictions of different widths between the voltage electrodes. The MR for fields parallel to the c-axis shows an anomalous hysteresis loop compatible with the behavior expected for granular superconductors. The smaller the constr

Didier Sornette, Ryan Woodard, Maxim Fedorovsky, Stefan Reimann

This is the second installment of the Financial Bubble Experiment. Here we provide the digital fingerprint of an electronic document in which we identify 7 bubbles in 7 different global assets; for 4 of these assets, we present windows of dates of the most likely ending time of each bubble. We will provide that document of the original analysis on 1 November

Yuval Shavitt, Noa Zilberman

The geographical location of Internet IP addresses has an importance both for academic research and commercial applications. Thus, both commercial and academic databases and tools are available for mapping IP addresses to geographic locations. Evaluating the accuracy of these mapping services is complex since obtaining diverse large scale ground truth is ver

Joaquim Martin, Mario Milman

We characterize Poincar\'{e} inequalities in metric spaces using rearrangement inequalities

Göran Fäldt

The coherent-nuclear reaction a + A -> a* + A is in the small-angle region dominated by the one-photon-exchange mechanism, often referred to as the Primakoff effect. In this region information about the electromagnetic decay a* -> a + gamma can be obtained. Well-known examples are the two-photon decays of the pi- and eta-mesons. Also decays of charged hadron

T. N. Pham

The octet-singlet $\eta -\eta^{\prime}$ mixing mass term could have a derivative $O(p^{2})$ term as found in recent analysis of the $\eta -\eta^{\prime}$ system. This term gives rise to an additional momentum-dependent pole contribution which is suppressed by a factor $m_{\eta}^{2}/m_{\eta^{\prime}}^{2}$ for $\eta$ relative to the $\eta^{\prime}$ amplitude.

Yousef Bisabr

There is a conformal equivalence between power law $f(R)$ theories and scalar field theories in which the scalar degree of freedom evolves under the action of an exponential potential function. In the scalar field representation there is a strong coupling of the scalar field with the matter sector due to the conformal transformation. We use chameleon mechani

A. Wagenpfahl, D. Rauh, M. Binder, C. Deibel

Measuring the current-voltage characteristic of organic bulk heterojunction solar devices sometimes reveals an s-shaped deformation. We qualitatively produce this behaviour by a numerical device simulation assuming a reduced surface recombination. Furthermore we show how to experimentally create these double diodes by applying an oxygen plasma etch on the in

L. E. Svistov, T. Fujita, H. Yamaguchi, S. Kimura

Magnetization of the frustrated $S=1/2$ chain compound LiCuVO$_4$, focusing on high magnetic field phases, is reported. Besides a spin-flop transition and the transition from a planar spiral to a spin modulated structure observed recently, an additional transition was observed just below the saturation field. This newly observed magnetic phase is considered