June 2009 arXiv papers — page 30

Giuseppe Vallone, Gaia Donati, Francesco De Martini, Paolo Mataloni

By using an optical device based on the integration of a GRaded-INdex (GRIN) rod lens and a single-mode optical fiber we efficiently collected photon pairs generated by spontaneous parametric down-conversion. We show that this system preserves the polarization entanglement of the 2-photon states. Hence this device, characterized by a remarkable easiness of a

D. Gora, M. Haag, M. Roth

Large surface detectors might be sensitive not only with respect to extensive air showers induced by ultra high energy neutrinos but also to showers induced by hypothetical objects like microscopic black-holes. Microscopic black-holes might be produced in high energy particle collisions with the center of mass energies above the fundamental scale of gravity.

Laurent Schoeffel

Deeply Virtual Compton Scattering (DVCS) in $ep$ collisions has emerged in recent years as a an essential reaction to obtain information on the correlation of partons in the hadron (proton) or on the transverse distribution of these partons. In these proceedings, we examine the lattest data from HERA (at low $x_{Bj}<10^{-2}$) and their impact on models. We a

Sven Friedemann, Niels Oeschler, Steffen Wirth, Frank Steglich

The Hall effect of LuRh2Si2--the non-magnetic homologue of the heavy-fermion material YbRh2Si2--is studied with two different setups: In the conventional single-field geometry, the field dependence is analyzed in terms of the differential Hall coefficient. Beyond that, the recently developed crossed-field experiment allows to examine the linear-response Hall

Sven Friedemann, Niels Oeschler, Cornelius Krellner, Christoph Geibel

Quantum criticality in Yb(Rh0.97Co0.03)2Si2 is investigated by means of resistivity and magnetoresistance. The partial substitution of Co leads to a stabilization of the magnetism as expected according to the application of chemical pressure for Yb systems. However, the signature of the Kondo-breakdown remains at the same position in the temperature-magnetic

Stefan Ohm, Dieter Horns, Olaf Reimer, Jim Hinton

Stellar clusters are potential acceleration sites of very-high-energy (VHE, E > 100GeV) particles since they host supernova remnants (SNRs) and pulsar wind nebulae (PWNe). Additionally, in stellar clusters, particles can also be accelerated e.g. at the boundaries of wind-blown bubbles, in colliding wind zones in massive binary systems or in the framework of

A. J. M. Medved

There has been much debate over the form of the quantum area spectrum for a black hole horizon, with the evenly spaced conception of Bekenstein having featured prominently in the discourse. In this letter, we refine a very recently proposed method for calibrating the Bekenstein form of the spectrum. Our refined treatment predicts, as did its predecessor, a u

Massimo Campostrini, Ettore Vicari

We develop a trap-size scaling theory for trapped particle systems at quantum transitions. As a theoretical laboratory, we consider a quantum XY chain in an external transverse field acting as a trap for the spinless fermions of its quadratic Hamiltonian representation. We discuss trap-size scaling at the Mott insulator to superfluid transition in the Bose-H

T. Fulop, I. Tsutsui

Boundary effects in quantum mechanics are examined by considering a partition wall inserted at the centre of a harmonic oscillator system. We put an equal number of particles on both sides of the impenetrable wall keeping the system under finite temperatures. When the wall admits distinct boundary conditions on the two sides, then a net force is induced on t

Arata Yamamoto

This letter presents a novel analysis of the action/energy density distribution around a static quark-antiquark pair in SU(3) lattice quantum chromodynamics. Using the Fourier transformation of the link variable, we remove the high-momentum gluon and extract the flux-tube component from the action/energy density. When the high-momentum gluon is removed, the

Laurent Bienvenu, Alexander Shen

The notion of an individual random sequence goes back to von Mises. We describe the evolution of this notion, especially the use of martingales (suggested by Ville), and the development of algorithmic information theory in 1960s and 1970s (Solomonov, Kolmogorov, Martin-Lof, Levin, Chaitin, Schnorr and others). We conclude with some remarks about the use of t

Z. R. Gong, Z. Song, C. P. Sun

We study the topological properties of Peierls transitions in a monovalent Möbius ladder. Along the transverse and longitudinal directions of the ladder, there exist plenty Peierls phases corresponding to various dimerization patterns. Resulted from a special modulation, namely, staggered modulation along the longitudinal direction, the ladder system in the

M. Heavner, D. R. Fatland, E. Hood, C. Connor

A sensor web is a collection of heterogeneous sensors which autonomously reacts to the observed environment. The SouthEast Alaska MOnitoring Network for Science, Technology, Education, and Research (SEAMONSTER) project has implemented a sensor web in partially glaciated watersheds near Juneau, Alaska, on the edge of the Juneau Icefield. By coupling the SEAMO

R. N. Bisset, P. B. Blakie

The c-field simulation technique is used to study a trapped quasi-two dimensional Bose gas. We calculate the central curvature of the system density and fluctuations of the condensate mode in the degenerate regime. These results provide new understanding of the system behavior in the region of the superfluid transition.

O. K. Lee, J. C. Ye

Multiple measurement vector (MMV) problem addresses the recovery of a set of sparse signal vectors that share common non-zero support, and has emerged an important topics in compressed sensing. Even though the fundamental performance limit of recoverable sparsity level has been formally derived, conventional algorithms still exhibit significant performance g

Xueliang Li, Hongping Ma

The energy $E(G)$ of a graph $G$ is defined as the sum of the absolute values of its eigenvalues. A graph $G$ of order $n$ is said to be hypoenergetic if $E(G)<n$. Majstorović et al. conjectured that complete bipartite graph $K_{2,3}$ is the only hypoenergetic connected quadrangle-containing graph with maximum degree $Δ\leq 3$. This paper is devoted to givin

Rong-Feng Shen, Bing Zhang

We constrain the distance of the Gamma-Ray Burst (GRB) prompt emission site from the explosion centre, R, by determining the location of the electron&#39;s self absorption frequency in the GRB prompt optical-to-X/gamma-ray spectral energy distribution, assuming that the optical and the gamma-ray emissions are among the same synchrotron radiation continuum of

I. Y. Park

We propose a full-fledged open string framework that seems suited to study the black hole information paradox. We set up a configuration to compute the scattering amplitude of a IIB open string around a D5-brane. The D5-brane is situated at the origin of a transverse D3-brane. A string perturbation theory is employed where the geometry of the D5-brane is tre

Fan Ge, Zhi-Wei Sun

For $m=3,4,\ldots$ those $p_m(x)=(m-2)x(x-1)/2+x$ with $x\in\mathbb Z$ are called generalized $m$-gonal numbers. Sun [13] studied for what values of positive integers $a,b,c$ the sum $ap_5+bp_5+cp_5$ is universal over $\mathbb Z$ (i.e., any $n\in\mathbb N=\{0,1,2,\ldots\}$ has the form $ap_5(x)+bp_5(y)+cp_5(z)$ with $x,y,z\in\mathbb Z$). We prove that $p_5+b

Takemi Yamada, Youichi Yamakawa, Yoshiaki Ōno

The electronic state around a single vacancy in silicon crystal is investigated by using the Green&#39;s function approach. The triply degenerate charge states are found to be widely extended and account for extremely large elastic softening at low temperature as observed in recent ultrasonic experiments. When we include the LS coupling $λ_{\rm Si}$ on each

Howard Baer, Andrew D. Box, Heaya Summy

We examine the minimal supergravity (mSUGRA) model under the assumption that the strong CP problem is solved by the Peccei-Quinn mechanism. In this case, the relic dark matter (DM) abundance consists of three components: {\it i}). cold axions, {\it ii}). warm axinos from neutralino decay, and {\it iii}). cold or warm thermally produced axinos. To sustain a h

Masanao Sato, Hideki Asada

We consider the effects of mutual transits by extrasolar planet-companion systems (in a true binary or a planet-satellite system) on light curves. We show that induced changes in light curves depend strongly on a ratio between a planet-companion&#39;s orbital velocity around their host star and a planet-companion&#39;s spin speed around their common center o

Brian A. Munson, Ismar Volic

We study the spaces of string links and homotopy string links in an arbitrary manifold using multivariable manifold calculus of functors. We construct multi-cosimplicial models for both spaces and deduce certain convergence properties of the associated Bousfield-Kan homotopy and cohomology spectral sequences when the ambient manifold is a Euclidean space of

Michele Ferraz Figueiro, Alberto Saa

We show that the common singularities present in generic modified gravity models governed by actions of the type $S=\int d^4x \sqrt{-g}f(R,ϕ,X)$, with $X= -{1/2}g^{ab}\partial_aϕ\partial_bϕ$, are essentially the same anisotropic instabilities associated to the hypersurface $F(ϕ)=0$ in the case of a non-minimal coupling of the type $F(ϕ)R$, enlightening the p

Chunhua Ma

We prove a general fluctuation limit theorem for Galton-Watson branching processes with immigration. The limit is a time-inhomogeneous OU type process driven by a spectrally positive Levy process. As applications of this result, we obtain some asymptotic estimates for the conditional least-squares estimator of the offspring means and variances of the offspri

Edi Halyo

We describe cosmic F--term strings with exponentially small tension which are D3 branes wrapped on deformed $A_3$ singularities. We show that brane instanton effects which can be calculated after a geometric transition give rise to an exponentially small volume for the node on which the D3 branes wrap leading to a string with small tension. We generalize our

Shun Watanabe, Ryutaroh Matsumoto, Tomohiko Uyematsu

The privacy amplification is a technique to distill a secret key from a random variable by a function so that the distilled key and eavesdropper&#39;s random variable are statistically independent. There are three kinds of security criteria for the key distilled by the privacy amplification: the normalized divergence criterion, which is also known as the wea

Carlos Gershenson

Short philosophical essay

Ajay Singh Negi, Chinedum O. Osuji

We monitor the relaxation of internal stresses in a fractal colloidal gel on cessation of flow and find a weak power law decay, $σ_i \sim t^{-α}$ over 5 decades of time where $α\approx 0.07$. The system exhibits physical aging of the elastic modulus, $G&#39; \sim t^β$, with $β\approx α$. Imposition of zero stress after waiting time $t_w$ results in strain re

Jacques L. Rubin

On the basis of the Woodhouse causal axiomatics, we show that conformal proper times and an extra variable in addition to those of space and time, precisely and physically identified from experimental examples, together give a physical justification for the `chronometric hypothesis&#39; of general relativity. Indeed, we show that, with a lack of these latter

Xudong Ma

In this paper, we propose an approximate semi-definite programming framework for demodulation and equalization of non-coherent ultra-wide-band communication systems with inter-symbol-interference. It is assumed that the communication systems follow non-linear second-order Volterra models. We formulate the demodulation and equalization problems as semi-defini

Mahdi Ramezani, Masoud Ardakani

Low-density parity-check (LDPC) codes have been used for communication over a two-user Gaussian broadcast channel. It has been shown in the literature that the optimal decoding of such system requires joint decoding of both user messages at each user. Also, a joint code design procedure should be performed. We propose a method which uses a novel labeling str

Steven K. Blau, Matt Visser, Andreas Wipf

We use zeta function techniques to give a finite definition for the Casimir energy of an arbitrary ultrastatic spacetime with or without boundaries. We find that the Casimir energy is intimately related to, but not identical to, the one-loop effective energy. We show that in general the Casimir energy depends on a normalization scale. This phenomenon has rel

M. Cranston, L. Koralov, S. Molchanov, B. Vainberg

We consider a model for the distribution of a long homopolymer with a zero-range potential at the origin in $\mathbb{R}^3$. The distribution can be obtained as a limit of Gibbs distributions corresponding to properly normalized potentials concentrated in small neighborhoods of the origin as the size of the neighborhoods tends to zero. The distribution depend

P. Kassotakis, N. Joshi

We construct 9-parameter and 13-parameter dynamical systems of the plane which map bi-quadratic curves to other bi-quadratic curves and return to the original curve after two iterations. These generalize the QRT maps which map each such curve to itself. The new families of maps include those that were found as reductions of integrable lattices.

R. Alonso, T. Guillot, T. Mazeh, S. Aigrain

We present a study of the light curve of the transiting exoplanet CoRoT-2b, aimed at detecting the secondary eclipse and measuring its depth. The data were obtained with the CoRoT satellite during its first run of more than 140 days. After filtering the low frequencies with a pre-whitening technique, we detect a 0.0060$\pm$0.0020% secondary eclipse centered

Kohtaro Tadaki

A real αis called recursively enumerable (&#34;r.e.&#34; for short) if there exists a computable, increasing sequence of rationals which converges to α. It is known that the randomness of an r.e. real αcan be characterized in various ways using each of the notions; program-size complexity, Martin-Löf test, Chaitin Ωnumber, the domination and Ω-likeness of α,

Maurilio Pannella, Armin Gabasch, Yuliana Goranova, Niv Drory

The Cosmic Evolution Survey (COSMOS) allows for the first time a highly significant census of environments and structures up to redshift one, as well as a full morphological description of the galaxy population. In this paper we present a study aimed to constrain the evolution, in the redshift range 0.2 < z < 1.2, of the mass content of different morphologic

D. E. Kharzeev

Very stringent experimental bounds exist on the amount of P and CP violation in strong interactions. Nevertheless, the presence of non-Abelian topological solutions and the axial anomaly make the issue of CP invariance in QCD non-trivial (&#34;the strong CP problem&#34;). Even in the absence of a global P and CP violation the fluctuations of topological char

S. Michelin, S. G. Llewellyn Smith

The influence of the bending rigidity of a flexible heaving wing on its propulsive performance in a two-dimensional imposed parallel flow is investigated in the inviscid limit. Potential flow theory is used to describe the flow over the flapping wing. The vortical wake of the wing is accounted for by the shedding of point vortices with unsteady intensity fro

Petr Zimak, Silvia Terenzi, Peter Strazewski

When the difference between changes in energy and entropy at a given temperature is correlated with the ratio between the same changes in energy and entropy at zero average free energy of an ensemble of similar but distinct molecule-sized objects, a highly significant linear dependence results from which a relationship between energy and entropy is derived a

Aeree Chung, Gopal Narayanan, Min S. Yun, Mark Heyer

We present 12CO J=1-->0 observations of ultraluminous infrared galaxies (ULIRGs) obtained using the Redshift Search Receiver (RSR) on the 14-m telescope of the Five College Radio Astronomy Observatory. The RSR is a novel, dual-beam, dual-polarization receiver equipped with an ultra-wideband spectrometer backend that is being built as a facility receiver for

O. Chis, D. Opris

In this paper we investigate some stochastic models for tumor-immune systems. To describe these models we used a Wiener process, as the noise has a stabilization effect. Their dynamics are studied in terms of stochastic stability in the equilibrium points, by constructing the Lyapunov exponent, depending on the parameters that describe the model. We have stu

Robert D. Blum, Peter J. McGregor

Gemini North adaptive optics imaging spectroscopy is presented for the Galactic ultra-compact HII (UCHII) region K3-50A. Data were obtained in the K-band using the Near-infrared Integral Field Spectrograph (NIFS) behind the facility adaptive optics module ALTAIR in natural guide star mode. The NIFS data cube reveals a complex spatial morphology across the 0.

S. Heinz, M. Brueggen, B. Morsony

One of the legacies of the {\rm Chandra} era is the discovery of AGN-inflated X-ray cavities in virtually all cool-core clusters, with mechanical luminosities comparable to or larger than the cluster cooling rate, suggesting that AGN might be responsible for heating clusters. This discovery poses a new set of questions that cannot be addressed by X-ray imagi

A. Lecavelier des Etangs, S. K. Sirothia, Gopal-Krishna, P. Zarka

We report a sensitive search for meter-wavelength emission at 244 and 614 MHz from HD189733b, the nearest known extrasolar transiting planet of `hot-Jupiter&#39; type. To discriminate any planetary emission from possible stellar or background contributions, we observed the system for 7.7 hours encompassing the planet&#39;s eclipse behind the host star. These

Scott S. Sheppard, Chadwick A. Trujillo

We present a systematic survey for satellites of Venus using the Baade-Magellan 6.5 meter telescope and IMACS wide-field CCD imager at Las Campanas observatory in Chile. In the outer portions of the Hill sphere the search was sensitive to a limiting red magnitude of about 20.4, which corresponds to satellites with radii of a few hundred meters when assuming

M. Mayor, X. Bonfils, T. Forveille, X. Delfosse

The GJ 581 planetary system was already known to harbour three planets, including two super-Earths planets which straddle its habitable zone. We report here the detection of an additional planet -- GJ 581e -- with a minimum mass of 1.9 M_earth. With a period of 3.15 days, it is the innermost planet of the system and has a ~5% transit probability. We also cor

Pieter G. van Dokkum, Mariska Kriek, Marijn Franx

Recent studies have found that the oldest and most luminous galaxies in the early Universe are surprisingly compact, having stellar masses similar to present-day elliptical galaxies but much smaller sizes. This finding has attracted considerable attention as it suggests that massive galaxies have grown by a factor of ~five in size over the past ten billion y

M. Chuaqui, P. Duren, B. Osgood

Combining the definition of Schwarzian derivative for conformal mappings between Riemannian manifolds given by Osgood and Stowe with that for parametrized curves in Euclidean space given by Ahlfors, we establish injectivity criteria for holomorphic curves $ϕ:\mathbb{D}\to\mathbb{C}^n$. The result can be considered a generalization of a classical condition fo

Ricardo G. Duran, Fernando Lopez Garcia

This paper deals with solutions of the divergence for domains with external cusps. It is known that the classic results in standard Sobolev spaces, which are basic in the variational analysis of the Stokes equations, are not valid for this class of domains. For some bounded domains $Ω\subset{\mathbb R}^n$ presenting power type cusps of integer dimension $m\l

R. I. Hynes, K. O&#39;Brien, F. Mullally, T. Ashcraft

We present two epochs of coordinated X-ray-optical timing observations of the black hole candidate Swift J1753.5-0127 during its 2005 outburst. The first epoch in July occurred at outburst peak. Two consecutive nights of observations using the McDonald Observatory Argos camera with the Rossi X-ray Timing Explorer show a consistent correlation with an immedia

Steven R. Cranmer

Classical Be stars are an enigmatic subclass of rapidly rotating hot stars characterized by dense equatorial disks of gas that have been inferred to orbit with Keplerian velocities. Although these disks seem to be ejected from the star and not accreted, there is substantial observational evidence to show that the stars rotate more slowly than required for ce

Nikolai V. Priezjev

The shear rate dependence of the slip length in thin polymer films confined between atomically flat surfaces is investigated by molecular dynamics simulations. The polymer melt is described by the bead-spring model of linear flexible chains. We found that at low shear rates the velocity profiles acquire a pronounced curvature near the wall and the absolute v

Martin Braure De Calignon, Luc Brun, Jacques-Olivier Lachaud

This paper defines the basis of a new hierarchical framework for segmentation algorithms based on energy minimization schemes. This new framework is based on two formal tools. First, a combinatorial pyramid encode efficiently a hierarchy of partitions. Secondly, discrete geometric estimators measure precisely some important geometric parameters of the region

G. W. Gibbons, C. A. R. Herdeiro, C. Rebelo

An explicit global and unique isometric embedding into hyperbolic 3-space, H^3, of an axi-symmetric 2-surface with Gaussian curvature bounded below is given. In particular, this allows the embedding into H^3 of surfaces of revolution having negative, but finite, Gaussian curvature at smooth fixed points of the U(1) isometry. As an example, we exhibit the glo

Jacques-Olivier Lachaud

This paper proposes a concise coding of the cells of n-dimensional finite regular grids. It induces a simple, generic and efficient framework for implementing classical digital topology data structures and algorithms. Discrete subsets of multidimensional images (e.g. regions, digital surfaces, cubical cell complexes) have then a common and compact representa

Daciberg Lima Gonçalves, John Guaschi

Let M be a compact, connected surface, possibly with a finite set of points removed from its interior. Let d,n be positive integers, and let N be a d-fold covering space of M. We show that the covering map induces an embedding of the n-th braid group B_n(M) of M in the (dn)-th braid group B_{dn}(N) of N, and give several applications of this result. First, w

M. Kromer, S. A. Sim, W. Hillebrandt

Despite the importance of Type Ia supernovae as standard candles for cosmology and to the chemical evolution of the Universe, we still have no consistent picture of the nature of these events. Much progress has been made in the hydrodynamical explosion modelling of supernovae Ia in the last few years and fully 3-D explosion models are now available. However

Holger Kösters

We investigate the second-order correlation function of the characteristic polynomial of a sample covariance matrix. Starting from an explicit formula for the generating function, we re-obtain several well-known kernels from random matrix theory.

F. C. Niestemski, Von Braun Nascimento, Biao Hu, Ward Plummer

The parent compounds of the recently discovered iron-arsenic (pnictide) high temperature superconductors transition into an intriguing spin density wave (SDW) phase at low temperatures. Progress in understanding this SDW state has been complicated by a complex band structure and by the fact that the spin, electronic, and structural degrees of freedom are clo

Ophir Setter

We present a general framework for computing two-dimensional Voronoi diagrams of different classes of sites under various distance functions. The framework is sufficiently general to support diagrams embedded on a family of two-dimensional parametric surfaces in $R^3$. The computation of the diagrams is carried out through the construction of envelopes of su

L. I. Plimak

Formal structure of phase-space path integrals based on different types of operator orderings is analysed.

Peter E. Hamlington, Werner J. A. Dahm

A new fundamentally-based formulation of nonlocal effects in the rapid pressure-strain correlation in turbulent flows has been obtained. The resulting explicit form for the rapid pressure-strain correlation accounts for nonlocal effects produced by spatial variations in the mean-flow velocity gradients, and is derived through Taylor expansion of the mean vel

A. Lopez-Ortega

We expound in detail a method frequently used to reduce the Dirac equation in D-dimensional (D >= 4) spherically symmetric spacetimes to a pair of coupled partial differential equations in two variables. As a simple application of these results we exactly calculate the quasinormal frequencies of the uncharged Dirac field propagating in the D-dimensional Nari

Joan E. Hart, Kenneth Kunen

Assuming PFA, every uncountable subset E of the plane meets some C^1 arc in an uncountable set. This is not provable from MA(aleph_1), although in the case that E is analytic, this is a ZFC result. The result is false in ZFC for C^2 arcs, and the counter-example is a perfect set.

P. R. Bertussi, A. L. Malvezzi, T. Paiva, R. R. dos Santos

We consider local magnetic moments coupled to conduction electrons with on-site attraction, in order to discuss the interplay between pairing and magnetic order. We probe the ground state properties of this model on a one-dimensional lattice through pair binding energies and several correlation functions, calculated by means of density-matrix renormalization

David W. Hughes, Michael R. E. Proctor

We re-examine the nature of the turbulent magnetic diffusivity tensor of mean field electrodynamics and show that an inconsistency arises if it is calculated via consideration of time-independent magnetic fields. Specifically, the predicted growth rate of the mean magnetic field is, in general, incorrect. We describe how the traditional expansion procedure f

Triantafyllos Xylouris

Let a and q be coprime natural numbers. In 1944 Linnik proved that the least prime in an arithmetic progression a mod q is less then C times q to the L. Since then the admissible value for the constant L has been improved several times, lastly by Heath-Brown in 1992 to L=5.5. In his article Heath-Brown describes several improvement potentials for his paper.

Edward Frenkel

The Langlands Program was launched in the late 60s with the goal of relating Galois representations and automorphic forms. In recent years a geometric version has been developed which leads to a mysterious duality between certain categories of sheaves on moduli spaces of (flat) bundles on algebraic curves. Three years ago, in a groundbreaking advance, Kapust

W. R. Webber, D. S. Intriligator

We have examined instigating events at the Sun that may be responsible for two of the most recent outer heliospheric kHz emissions detected by the University of Iowa plasma wave detector on Voyager 1 starting at 2004.64 and 2006.39, respectively. These interplanetary events have been followed outward from the Sun using plasma and cosmic ray data from Ulysses

C. M. Hull, U. Lindstrom, L. Melo dos Santos, R. von Unge

We investigate the target space geometry of supersymmetric sigma models in two dimensions with Euclidean signature, and the conditions for N=2 supersymmetry. For a real action, the geometry for the N=2 model is not the generalized Kahler geometry that arises for Lorentzian signature, but is an interesting modification of this which is not a complex geometry.

P. Godon, E. M. Sion, P. E. Barrett, P. Szkody

We present an analysis of the FUSE spectra of eight high-declination dwarf novae obtained from a Cycle 7 FUSE survey. These DN systems have not been previously studied in the UV and little is known about their white dwarfs (WDs) or accretion disks. We carry out the spectral analysis of the FUSE data using synthetic spectra generated with the codes TLUSTY and

Miguel Navascues, Masaki Owari, Martin B. Plenio

Using new results on the separability properties of bosonic systems, we provide a new complete criterion for separability. This criterion aims at characterizing the set of separable states from the inside by means of a sequence of efficiently solvable semidefinite programs. We apply this method to derive arbitrarily good approximations to the optimal measure

Miguel Navascues, Masaki Owari, Martin B. Plenio

In this paper, we present new progress on the study of the symmetric extension criterion for separability. First, we show that a perturbation of order O(1/N) is sufficient and, in general, necessary to destroy the entanglement of any state admitting an N Bose symmetric extension. On the other hand, the minimum amount of local noise necessary to induce separa

Thorsten Ohl, Alexander Schenkel

We derive noncommutative Einstein equations for abelian twists and their solutions in consistently symmetry reduced sectors, corresponding to twisted FRW cosmology and Schwarzschild black holes. While some of these solutions must be rejected as models for physical spacetimes because they contradict observations, we find also solutions that can be made compat

Mounir Nisse

Let $V$ be a complex algebraic hypersurface defined by a polynomial $f$ with Newton polytope $\Delta$. It is well known that the spine of its amoeba has a structure of a tropical hypersurface. We prove in this paper that there exists a complex tropical hypersurface $V_{\infty, f}$ such that its coamoeba is homeomorphic to the closure in the real torus of the

O. Cakir, K. O. Ozansoy

In this work, we study the possible unparticle signatures through tau pair production e+e- -> tau+tau- process at the low energy particle factories. We take into account lepton flavor conserving (s-channel) and violating (t-channel) couplings for the unparticle leptonic interactions. For different values of the scaling parameter d we extract upper limits on

Peter Schupp, Sergey Solodukhin

An exact spherically symmetric black hole solution of a recently proposed noncommutative gravity theory based on star products and twists is constructed. This is the first nontrivial exact solution of that theory. The resulting noncommutative black hole quite naturally exhibits holographic behavior; outside the horizon it has a fuzzy shell-like structure, in

M. Kholmyansky, L. Moriconi, R. M. Pereira, A. Tsinober

The Log-Poisson phenomenological description of the turbulent energy cascade is evoked to discuss high-order statistics of velocity derivatives and the mapping between their probability distribution functions at different Reynolds numbers. The striking confirmation of theoretical predictions suggests that numerical solutions of the flow, obtained at low/mode

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

We present a global fit to the structure function F_2 measured in lepton-proton experiments at small values of Bjorken-x, x< 0.01, for all experimentally available values of Q^2, 0.045< Q^2 < 800 GeV^2, using the Balitsky -Kovchegov equation including running coupling corrections. Using our fits to F_2, we reproduce available data for F_L and perform predict

Gautier Verhille, Nicolas Plihon, Grégory Fanjat, Romain Volk

A synthetic fluid dynamo built in the spirit of the Bullard device [E. C. Bullard, Proc. Camb. Phil. Soc., 51, 744 (1955)] is investigated. It is a two-step dynamo in which one process stems from the fluid turbulence, while the other part is an alpha effect achieved by a linear amplification of currents in external coils [M. Bourgoin et al., New J. Phys., 8,

David Wallace

I develop the decision-theoretic approach to quantum probability, originally proposed by David Deutsch, into a mathematically rigorous proof of the Born rule in (Everett-interpreted) quantum mechanics. I sketch the argument informally, then prove it formally, and lastly consider a number of proposed ``counter-examples&#39;&#39; to show exactly which premises

F. De Vieilleville, Jacques-Olivier Lachaud, F. Feschet

Discrete geometric estimators approach geometric quantities on digitized shapes without any knowledge of the continuous shape. A classical yet difficult problem is to show that an estimator asymptotically converges toward the true geometric quantity as the resolution increases. We study here the convergence of local estimators based on Digital Straight Segme

Diana Savin, Cristina Flaut, Camelia Ciobanu

In this paper, we obtain some properties of the symbol algebras, starting from their connections with the quaternion and cyclic algebras over a field $K_{p},$% where $K$ is an algebraic number field, $p$ is a prime in $K$ and $K_{p}$ is the completion of $K$ with respect to $p-$ adic valuation, in the case when $K=\Bbb{Q}(\varepsilon), \varepsilon ^{3}=1,\va

Matt A. Wood, David M. Thomas, James C. Simpson

Negative superhumps in cataclysmic variable systems result when the accretion disc is tilted with respect to the orbital plane. The line of nodes of the tilted disc precesses slowly in the retrograde direction, resulting in a photometric signal with a period slightly less than the orbital period. We use the method of smoothed particle hydrodynamics to simula

Nick E. Mavromatos

I discuss a model inspired from the string/brane framework, in which our Universe is represented as a three brane, propagating in a bulk space time punctured by D0-brane (D-particle) defects. As the D3-brane world moves in the bulk, the D-particles cross it, and from an effective observer on D3 the situation looks like a ``space-time foam&#39;&#39; with the

V. A. Sheminova

The results of 2D MHD simulations of solar magnetogranulation are used to analyze the horizontal magnetic fields and the response of the synthesized Stokes profiles of the FeI 1564.85 nm line to the magnetic fields. Selected 1.5-h series of the 2D MHD models reproduces a region of the network fields with their immediate surrounding on the solar surface with

F. van Leeuwen, A. N. Morgan, D. L. Harrison

We describe a method for deriving the position and flux of point and compact sources observed by a scanning survey mission. Results from data simulated to test our method are presented, which demonstrate that at least a 10-fold improvement is achievable over that of extracting the image parameters, position and flux, from the equivalent data in the form of p

Artem Chernikov, Pierre Simon

In this short note we show that if we add predicate for a dense complete indiscernible sequence in a dependent theory then the result is still dependent. This answers a question of Baldwin and Benedikt and implies that every unstable dependent theory has a dependent expansion interpreting linear order.

Ekaterina Kirik, Tat&#39;yana Yurgel&#39;yan, Dmitriy Krouglov

A stochastic cellular automata (CA) model for pedestrian dynamics is presented. Our goal is to simulate different types of pedestrian movement, from regular to panic. But here we emphasize regular situations which imply that pedestrians analyze environment and choose their route more carefully. And transition probabilities have to depict such effect. The pot

Simone De Liberato, Dario Gerace, Iacopo Carusotto, Cristiano Ciuti

We present a theory of the quantum vacuum radiation that is generated by a fast modulation of the vacuum Rabi frequency of a single two-level system strongly coupled to a single cavity mode. The dissipative dynamics of the Jaynes-Cummings model in the presence of anti-rotating wave terms is described by a generalized master equation including non-Markovian t

M. Bonaldi, L. Conti, P. De Gregorio, L. Rondoni

We analyze heat and work fluctuations in the gravitational wave detector AURIGA, modeled as a macroscopic electromechanical oscillator in contact with a thermostat and cooled by an active feedback system. The oscillator is driven to a steady state by the feedback cooling, equivalent to a viscous force. The experimentally measured fluctuations are in agreemen

Marco Donatelli

We study strategies for increasing the precision in the blurring models by maintaining a complexity in the related numerical linear algebra procedures (matrix-vector product, linear system solution, computation of eigenvalues etc.) of the same order of the celebrated Fast Fourier Transform. The key idea is the choice of a suitable functional basis for repres

Ellyn K. Baines, Harold A. McAlister, Theo A. ten Brummelaar, J. Sturmann

We directly measured the angular diameters for 11 exoplanet host stars using Georgia State University&#39;s CHARA Array interferometer and calculated their linear radii and effective temperatures. The sample tends towards evolving or evolved stars and includes one dwarf, four subgiants, and six giants. We then estimated masses and ages for the stars using ou

Edith Adan-Bante, John Harris, Helena Verrill

Let A_n be the alternating group on n letters. For n>5, we describe the elements alpha, beta in A_n when alpha^{A_n} beta^{A_n} is the union of at most four distinct conjugacy classes.

Thomas Durt

According to the so-called ``Quantum Darwinist&#39;&#39; approach, the emergence of ``classical islands&#39;&#39; from a quantum background is assumed to obey a (selection) principle of maximal information. We illustrate this idea by considering the coupling of two particles that interact through a position-dependent potential. This approach sheds a new ligh

Artur Ruuge

The Kochen-Specker theorem states that a 3-dimensional complex Euclidean space admits a finite configuration of projective lines such that the corresponding quantum observables (the orthogonal projectors) cannot be assigned with 0 and 1 values in a classically consistent way. This paper shows that the irreducible root systems of exceptional and of non-crysta

Artur Ruuge

A new infinite family of examples of finite non-bicolorable configurations of rays in Hilbert space is described. Such configurations appear in the analysis of quantum mechanics in terms of Bell&#39;s inequalities and Kochen-Specker theorem and illustrate that there is no measurable space in the background of the probability model of a quantum system. The me

Christian Borghesi

Twelve turnout rates of French national elections by municipality have shown statistical regularities, neither depend on the nature of the election, nor on the national turnout level. Three quantitative predictions about voter turnout at the French 2009 European election were made in arXiv:0905.4578. Here, we give the results of these three predictions. Each