January 2008 arXiv papers — page 7

Erica Walker, Raza M. Syed

Given the recent tragedy involving a 350 pound Siberian Tiger and the death of teenager Carlos Souza Jr., one must ask a fundamental question: Can a tiger overcome an obstacle that is thirty-three feet away and twelve and a half feet tall? Are these dimensions sufficient enough to protect the zoo-visitors from a potential escape and/or attack? To answer thes

Rishi Khatri, Benjamin D. Wandelt

We calculate the contribution of cosmic strings arising from a phase transition in the early universe, or cosmic superstrings arising from brane inflation, to the cosmic 21 cm power spectrum at redshifts z > 30. Future experiments can exploit this effect to constrain the cosmic string tension Gu and probe virtually the entire brane inflation model space allo

David Charlton, Erik D. Demaine, Martin L. Demaine, Gregory Price

We give a counterexample to a conjecture of Poon [Poo06] that any orthogonal tree in two dimensions can always be flattened by a continuous motion that preserves edge lengths and avoids self-intersection. We show our example is locked by extending results on strongly locked self-touching linkages due to Connelly, Demaine and Rote [CDR02] to allow zero-length

Tobias Reichenbach, Thomas Franosch, Erwin Frey

We investigate the delocalization transition appearing in an exclusion process with two internal states resp. on two parallel lanes. At the transition, delocalized domain walls form in the density profiles of both internal states, in agreement with a mean-field approach. Remarkably, the topology of the system's phase diagram allows for the delocalization

M. Kachelriess

I give a concise introduction into high energy cosmic ray physics, including also few related aspects of high energy gamma-ray and neutrino astrophysics. The main emphasis is placed on astrophysical questions, and the level of the presentation is kept basic.

Tomasz Radozycki

Fermion propagator of the Schwinger Model is revisited from the point of view of its infrared behavior. The values of anomalous dimensions are found in arbitrary covariant gauge and in all contributing instanton sectors. In the case of a gauge invariant, but path dependent propagator, the exponential dependence, instead of power law one, is established for t

Ovidiu I. Patu, Vladimir E. Korepin, Dmitri V. Averin

We have obtained an expansion of the reduced density matrices (or, equivalently, correlation functions of the fields) of impenetrable one-dimensional anyons in terms of the reduced density matrices of fermions using the mapping between anyon and fermion wavefunctions. This is the generalization to anyonic statistics of the result obtained by A. Lenard for bo

Brian Batell, Tony Gherghetta

We present a solution of the five-dimensional gravity-dilaton-tachyon equations of motion with a pure AdS_5 metric and a quadratic dilaton and linear tachyon in conformal coordinates. This leads to an infrared soft wall model where the dilaton profile gives rise to linear Regge trajectories for the four-dimensional mass spectrum of the dual gauge theory. Eve

Francesco Shankar, Xinyu Dai, Gregory R. Sivakoff

We find that the fraction of classical Broad Absorption Line quasars (BALQSOs) among the FIRST radio sources in the Sloan Data Release 3, is 20.5^{+7.3}_{-5.9}% at the faintest radio powers detected (L_{\rm 1.4 GHz}~10^{32} erg/s), and rapidly drops to <8% at L_{\rm 1.4 GHz}~3*10^{33} erg/s. Similarly, adopting the broader Absorption Index (AI) definition of

Matthew Anderson, Eric W. Hirschmann, Luis Lehner, Steven L. Liebling

We investigate the influence of magnetic fields upon the dynamics of and resulting gravitational waves from a binary neutron star merger in full general relativity coupled to ideal magnetohydrodynamics (MHD). We consider two merger scenarios, one where the stars begin with initially aligned poloidal magnetic fields and one with no magnetic field. Both merger

K. -I. Nishikawa, Y. Mizuno, G. J. Fishman, P. Hardee

Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets show that acceleration occurs within t

Frank Petriello, Seth Quackenbush

We study the properties of potential new Z&#39; gauge bosons produced through the Drell-Yan mechanism at the LHC. Our analysis is performed using a fully differential next-to-leading order QCD calculation with spin correlations, interference effects, and experimental acceptances included. We examine the distinguishability of different models and the feasibil

Himel Ghosh, Smita Mathur, Fabrizio Fiore, Laura Ferrarese

We are conducting a search for supermassive black holes (SMBHs) with masses below 10^7 M_sun by looking for signs of extremely low-level nuclear activity in nearby galaxies that are not known to be AGNs. Our survey has the following characteristics: (a) X-ray selection using the Chandra X-ray Observatory, since x-rays are a ubiquitous feature of AGNs; (b) Em

Dong Xu, Yuan-Chuan Zou, Yi-Zhong Fan

We analyze the hitherto available space-based X-ray data as well as ground-based optical data of the X-ray transient 080109/SN2008D. From the data we suggest that (i) The initial transient (\lesssim 800 sec) is attributed to the reverse shock emission of a mildly relativistic (Γ\sim a few) outflow stalled by the dense stellar wind. (ii) The subsequent X-ray

J. Hoyos, A. Reisenegger, J. A. Valdivia

This paper is the first in a series aimed at understanding the long-term evolution of neutron star magnetic fields. We model the stellar matter as an electrically neutral and lightly ionized plasma composed of three moving particle species: neutrons, protons, and electrons, which can be converted into each other by weak interactions (beta decays), suffer bin

Christian W. Bauer, Frank J. Tackmann, Jesse Thaler

We show how many contemporary issues in event generation can be recast in terms of partonic calculations with a matching scale. This framework is called GenEvA, and a key ingredient is a new notion of phase space which avoids the problem of phase space double-counting by construction and includes a built-in definition of a matching scale. This matching scale

Elena Dubrova

Conventional Non-Linear Feedback Shift Registers (NLFSRs) use the Fibonacci configuration in which the value of the first bit is updated according to some non-linear feedback function of previous values of other bits, and each remaining bit repeats the value of its previous bit. We show how to transform the feedback function of a Fibonacci NLFSR into several

Christian W. Bauer, Frank J. Tackmann, Jesse Thaler

We introduce a new efficient algorithm for phase space generation. A parton shower is used to distribute events across all of multiplicity, flavor, and phase space, and these events can then be reweighted to any desired analytic distribution. To verify this method, we reproduce the e+e- -> n jets tree-level result of traditional matrix element tools. We also

Ramon van Handel

We consider a discrete time hidden Markov model where the signal is a stationary Markov chain. When conditioned on the observations, the signal is a Markov chain in a random environment under the conditional measure. It is shown that this conditional signal is weakly ergodic when the signal is ergodic and the observations are nondegenerate. This permits a de

Tage Christensen, Jeppe C. Dyre

The coupling between mechanical and thermal properties due to thermal expansion complicates the problem of measuring frequency-dependent thermoviscoelastic properties, in particular for highly viscous liquids. A simplification arises if there is spherical symmetry where - as detailed in the present paper - the thermoviscoelastic problem may be solved analyti

Thomas E. Mark

Fintushel and Stern have proved that if S \subset X is a symplectic surface in a symplectic 4-manifold such that S has simply-connected complement and nonnegative self-intersection, then there are infinitely many topologically equivalent but smoothly distinct embedded surfaces homologous to S. Here we extend this result to include symplectic surfaces whose s

Wolfgang Altmannshofer, Diego Guadagnoli, Stuart Raby, David M. Straub

We address the viability of exact Yukawa unification in the context of general SUSY GUTs with universal soft-breaking sfermion and gaugino mass terms at the GUT scale. We find that this possibility is challenged, unless the squark spectrum is pushed well above the limits allowed by naturalness. This conclusion is assessed through a global fit using electrowe

Manuel de Leon, Juan Carlos Marrero, D. Martin de Diego

In this paper, we study the underlying geometry in the classical Hamilton-Jacobi equation. The proposed formalism is also valid for nonholonomic systems. We first introduce the essential geometric ingredients: a vector bundle, a linear almost Poisson structure and a Hamiltonian function, both on the dual bundle (a Hamiltonian system). From them, it is possib

Roman M. Lutchyn, Pavel Nagornykh, Victor M. Yakovenko

We present a gauge-invariant theory of the electromagnetic response of a chiral px+ipy superconductor in the clean limit. Due to the spontaneously broken time-reversal symmetry, the effective action of the system contains an anomalous term not present in conventional superconductors. As a result, the electromagnetic charge and current responses contain anoma

L. Ya. Glozman, A. V. Nefediev

We compare axial charges of excited nucleons, as predicted by the chiral symmetry restoration picture, with the traditional, moderately successful for the ground-state baryons SU(6) symmetry. The axial charges of excited nucleons can (and will) be measured in lattice QCD simulations, and comparison of the lattice results with the two different symmetry schem

Alexander I. Poteryaev, Michel Ferrero, Antoine Georges, Olivier Parcollet

We investigate a quarter-filled two-band Hubbard model involving a crystal-field splitting, which lifts the orbital degeneracy as well as an inter-orbital hopping (inter-band hybridization). Both terms are relevant to the realistic description of correlated materials such as transition-metal oxides. The nature of the Mott metal-insulator transition is clarif

Borut Bajc, Alejandra Melfo

We study the possibility of obtaining metastable supersymmetry breaking vacua in a perturbative gauge theory without singlet fields, thus allowing for scenarios where a grand unified symmetry and supersymmetry are broken by the same sector. We show some explicit SU(5) examples. The minimal renormalizable example requires the use of two adjoints, but it is sh

A. Courtoy, F. Fratini, S. Scopetta, V. Vento

We develop a formalism to evaluate the Sivers function. The approach is well suited for calculations which use constituent quark models to describe the structure of the nucleon. A non-relativistic reduction of the scheme is performed and applied to the Isgur-Karl model of hadron structure. The results obtained are consistent with a sizable Sivers effect and

William H. Meeks, Joaquin Perez, Antonio Ros

Suppose ${\cal L}$ is a lamination of a Riemannian manifold by hypersurfaces with the same constant mean curvature. We prove that every limit leaf of ${\cal L}$ is stable for the Jacobi operator. A simple but important consequence of this result is that the set of stable leaves of ${\cal L}$ has the structure of a lamination.

Yury Arlinskii

Let $\mathfrak M$ and $\mathfrak N$ be separable Hilbert spaces and let $Θ(λ)$ be a function from the Schur class ${\bf S}(\mathfrak M,\mathfrak N)$ of contractive functions holomorphic on the unit disk. The operator generalization of the classical Schur algorithm associates with $Θ$ the sequence of contractions (the Schur parameters of $Θ$) $Γ_0=Θ(0)\in \bL

A. D. Ludlow, T. Zelevinsky, G. K. Campbell, S. Blatt

Optical atomic clocks promise timekeeping at the highest precision and accuracy, owing to their high operating frequencies. Rigorous evaluations of these clocks require direct comparisons between them. We have realized a high-performance remote comparison of optical clocks over km-scale urban distances, a key step for development, dissemination, and applicat

S. Aoki, H. Fukaya, S. Hashimoto, J. Noaki

We present a two-flavor QCD calculation of $B_K$ on a $16^3 \times 32$ lattice at $a\sim 0.12$ fm (or equivalently $a^{-1}\sim$1.67 GeV). Both valence and sea quarks are described by the overlap fermion formulation. The matching factor is calculated non-perturbatively with the so-called RI/MOM scheme. We find that the lattice data are well described by the n

Luca Amendola, Christos Charmousis, Stephen C. Davis

In order for a modified gravity model to be a candidate for cosmological dark energy it has to pass stringent local gravity experiments. We find that a Brans-Dicke (BD) theory with well-defined second order corrections that include the Gauss-Bonnet term possess this feature. We construct the generic second order theory that gives, to linear order, a BD metri

Eung Jin Chun, Hang Bae Kim, Kazunori Kohri, David H. Lyth

If the spontaneous breaking of Peccei-Quinn symmetry comes from soft supersymmetry breaking, the fermionic partners of the symmetry-breaking fields have mass of order the gravitino mass, and are called flatinos. The lightest flatino, called here the flaxino, is a CDM candidate if it is the lightest supersymmetric particle. We here explore flaxino dark matter

Seid Bahlali

We consider a stochastic control problem where the set of strict (classical) controls is not necessarily convex and the the variable control has two components, the first being absolutely continuous and the second singular. The system is governed by a nonlinear stochastic differential equation, in which the absolutely continuous component of the control ente

Erek Bilgici, Falk Bruckmann, Christof Gattringer, Christian Hagen

We construct a new order parameter for finite temperature QCD by considering the quark condensate for U(1)-valued temporal boundary conditions for the fermions. Fourier transformation with respect to the boundary condition defines the dual condensate. This quantity corresponds to an equivalence class of Polyakov loops, thereby being an order parameter for th

Seid Bahlali

Stochastic maximum principle of nonlinear controlled forward-backward systems, where the set of strict (classical) controls need not be convex and the diffusion coefficient depends explicitly on the variable control, is an open problem impossible to solve by the classical method of spike variation. In this paper, we introduce a new approach to solve this ope

Daniel Arteaga

We analyze the particle-like excitations arising in relativistic field theories in states different than the vacuum. The basic properties characterizing the quasiparticle propagation are studied using two different complementary methods. First we introduce a frequency-based approach, wherein the quasiparticle properties are deduced from the spectral analysis

Johan Noldus

The first part of this work deals with the development of a natural differential calculus on non-commutative manifolds. The second part extends the covariance and equivalence principle as well studies its kinematical consequences such as the arising of gauge theory. Furthermore, a manifestly causal and covariant formulation of quantum field theory is present

John Veitch, Alberto Vecchio

Ground-based gravitational wave laser interferometers (LIGO, GEO-600, Virgo and Tama-300) have now reached high sensitivity and duty cycle. We present a Bayesian evidence-based approach to the search for gravitational waves, in particular aimed at the followup of candidate events generated by the analysis pipeline. We introduce and demonstrate an efficient m

Y. B. Sherkunov, A. Pratap, B. Muzykantskii, N. d&#39;Ambrumenil

Provided the measuring time is short enough, the full counting statistics (FCS) of the charge pumped across a barrier as a result of a series of voltage pulses are shown to be equivalent to the geometry of two planes. This formulation leads to the FCS without the need for the usual non-equilibrium (Keldysh) transport theory or the direct computation of the d

William Matthews, Andreas Winter

Motivated by the desire to better understand the class of quantum operations on bipartite systems that preserve positivity of partial transpose (PPT operations) and its relation to the class LOCC (local operations and classical communication), we present some results on deterministic bipartite pure state transformations by PPT operations. Restricting our att

W. Knafo, C. Meingast, A. Inaba, Th. Wolf

A study by specific heat of a polycrystalline sample of the low-dimensional magnetic system Y$_2$BaCuO$_5$ is presented. Magnetic fields up to 14 T are applied and permit to extract the ($T$,$H$) phase diagram. Below $μ_0H^*\simeq2$ T, the Néel temperature, associated with a three-dimensional antiferromagnetic long-range ordering, is constant and equals $T_N

Filipe Moura

We start by a concise yet thorough revision of four-dimensional superspace supergravity. We present curved superspace geometry, for arbitrary N, including torsion, curvature and Bianchi identities. We motivate the choice of torsion constraints. We then consider the particular cases of N=1,2. In both cases we show how Poincare supergravity can be obtained fro

Gianni Tedesco, Uwe Aickelin

Network intrusion detection systems are themselves becoming targets of attackers. Alert flood attacks may be used to conceal malicious activity by hiding it among a deluge of false alerts sent by the attacker. Although these types of attacks are very hard to stop completely, our aim is to present techniques that improve alert throughput and capacity to such

Uwe Aickelin

Over the last few years, more and more heuristic decision making techniques have been inspired by nature, e.g. evolutionary algorithms, ant colony optimisation and simulated annealing. More recently, a novel computational intelligence technique inspired by immunology has emerged, called Artificial Immune Systems (AIS). This immune system inspired technique h

Uwe Aickelin, Edmund Burke, Aniza Din

Artificial immune system can be used to generate schedules in changing environments and it has been proven to be more robust than schedules developed using a genetic algorithm. Good schedules can be produced especially when the number of the antigens is increased. However, an increase in the range of the antigens had somehow affected the fitness of the immun

L. Moli, A. Rodriguez, G. Seco-Granados

This paper has been withdrawn by the author. It will be published again after submission to a journal.

Uwe Aickelin, Qi Chen

We combine Artificial Immune Systems &#39;AIS&#39;, technology with Collaborative Filtering &#39;CF&#39; and use it to build a movie recommendation system. We already know that Artificial Immune Systems work well as movie recommenders from previous work by Cayzer and Aickelin 3, 4, 5. Here our aim is to investigate the effect of different affinity measure al

J. Emeterio Navarro Barrientos, Frank E. Walter, Frank Schweitzer

We study the performance of various agent strategies in an artificial investment scenario. Agents are equipped with a budget, $x(t)$, and at each time step invest a particular fraction, $q(t)$, of their budget. The return on investment (RoI), $r(t)$, is characterized by a periodic function with different types and levels of noise. Risk-avoiding agents choose

Maximo Banados

We argue that Einstein gravity coupled to a Born-Infeld theory provides an attractive candidate to represent dark matter and dark energy. For cosmological models, the Born-Infeld field has an equation of state which interpolates between matter, w=0 (small times), and a cosmological constant w=-1 (large times). On galactic scales, the Born-Infeld field predic

O. Linnyk, E. L. Bratkovskaya, W. Cassing

Within the Hadron-String Dynamics (HSD) transport approach we study the suppression pattern of charmonia at RHIC with respect to centrality and rapidity employing various model concepts such as variants of the &#39;comover absorption&#39; model or the &#39;charmonium melting&#39; scenario. We find that especially the ratio of the forward to mid-rapidity nucl

G. Berkolaiko, B. Winn

We investigate the equivalence between spectral characteristics of the Laplace operator on a metric graph, and the associated unitary scattering operator. We prove that the statistics of level spacings, and moments of observations in the eigenbases coincide in the limit that all bond lengths approach a positive constant value.

H. Abuki, M. Ciminale, R. Gatto, N. D. Ippolito

We study the phase diagram and the pion modes in the electrically neutral two flavor PNJL model. One of the main result of this paper is that when electrical neutrality is required, pions do not condense in the ground state of the model: the isospin chemical potential $μ_I = -μ_e/2$ is always smaller than the value required for pion condensation to occur. Mo

Chad Hanna, Miguel Megevand, Evan Ochsner, Carlos Palenzuela

Recent advances in the description of compact binary systems have produced gravitational waveforms that include inspiral, merger and ring-down phases. Comparing results from numerical simulations with those of post-Newtonian (PN), and related, expansions has provided motivation for employing PN waveforms in near merger epochs when searching for gravitational

Petr Dunin-Barkowski, Alexei Sleptsov

Reparametrization invariant Lagrangian theories with higher derivatives are considered. We investigate the geometric structures behind these theories and construct the Hamiltonian formalism in a geometric way. The Legendre transformation which corresponds to the transition from the Lagrangian formalism to the Hamiltonian formalism is non-trivial in this case

Guillaume Pouchin

After establishing a geometric Schur-Weyl duality in a general setting, we recall this duality in type A in the finite and affine case. We extend the duality in the affine case to positive parts of the affine algebras. The positive parts have nice ideals coming from geometry, allowing duality for quotients. Some of the quotients of the positive affine Hecke

Qi Chen, Uwe Aickelin

We apply the Artificial Immune System (AIS) technology to the Collaborative Filtering (CF) technology when we build the movie recommendation system. Two different affinity measure algorithms of AIS, Kendall tau and Weighted Kappa, are used to calculate the correlation coefficients for this movie recommendation system. From the testing we think that Weighted

Erwan Brugalle Oliver Labs

It is classically known that a real cubic surface in the real projective 3-space cannot have more than one solitary point (locally given by x^2+y^2+z^2=0) whereas it can have up to four nodes (x^2+y^2-z^2=0). We show that on any surface of degree at least 3 in the real projective 3-space, the maximum possible number of solitary points is strictly smaller tha

I. M. Narodetskii, C. Semay, A. I. Veselov

We provide a check of the accuracy of the auxiliary field formalism used to derive the Effective Hamiltonian for baryons in the Field Correlator Method. To this end we compare the solutions for the Effective Hamiltonian with those obtained from the solution of the Salpeter equation. Comparing these results gives a first estimate of the systematic uncertainty

J. X. Zheng-Johansson

We set up the Maxwell&#39;s equations and the corresponding classical wave equations for the electromagnetic waves which together with the generating source, a traveling oscillatory charge of zero rest mass, comprise a particle traveling in the force field of an usual conservative potential and an additional frictional force $f$. At the de Broglie wavelength

Mehdi Talamali, Viljo Petäjä, Damien Vandembroucq, Stéphane Roux

We use a power expansion representation of plane elasticity complex potentials due to Kolossov and Muskhelishvili, to compute the elastic fields induced by a localized plastic deformation event. Far from its center, the dominant contributions correspond to first order singularities of quadrupolar and dipolar symmetry which can be associated respectively to p

Andrew W. Baggaley, Carlo F. Barenghi, Anvar Shukurov

Using a multi-scaled, chaotic flow known as the KS model of turbulence, we investigate the dependence of Lyapunov exponents on various characteristics of the flow. We show that the KS model yields a power law relation between the Reynolds number and the maximum Lyapunov exponent, which is similar to that for a turbulent flow with the same energy spectrum. Ou

Yuri B. Gaididei, Volodymyr P. Kravchuk, Franz G. Mertens, Denis D. Sheka

A magnetic nanoparticle in a vortex state is a promising candidate for the information storage. One bit of information corresponds to the upward or downward magnetization of the vortex core (vortex polarity). Generic properties of the vortex polarity switching are insensitive of the way how the vortex dynamics was excited: by an AC magnetic field, or by an e

S. S. Kutateladze

This is a short overview of the origins of distribution theory as well as the life of Sergei Sobolev (1908--1989) and his contribution to the formation of the modern outlook of mathematics.

Yoh Tanimoto

We consider cones in a Hilbert space associated to two von Neumann algebras and determine when one algebra is included in the other. If a cone is assocated to a von Neumann algebra, the Jordan structure is naturally recovered from it and we can characterize projections of the given von Neumann algebra with the structure in some special situations.

P. Braun-Munzinger, J. Wambach

A fundamental question of physics is what ultimately happens to matter as it is heated or compressed. In the realm of very high temperature and density the fundamental degrees of freedom of the strong interaction, quarks and gluons, come into play and a transition from matter consisting of confined baryons and mesons to a state with &#39;liberated&#39; quark

Vincent Mathieu

These notes are a short introduction to the pinch technique. We present the one-loop calculations for basic QCD Green&#39;s functions. The equivalence between the pinch technique and the background field method is explicitly shown at the one-loop level. We review the absorptive pinch technique in the last sections. These lectures are a compilation of relevan

Teruhiko Soma

We present a new proof of the bi-Lipschitz model theorem, which occupies the main part of the Ending Lamination Conjecture proved by Minsky and Brock-Canary-Minsky. Our proof is done by using techniques of standard hyperbolic geometry as much as possible.

Markus Schweighofer

This paper has been withdrawn by the author since $U$ in Lemma 2 is in general not a subspace.

Nakia Carlevaro, Orchidea Maria Lecian, Giovanni Montani

A gauge theory of the Lorentz group, based on the different behavior of spinors and vectors under local transformations, is formulated in a flat space-time and the role of the torsion field within the generalization to curved space-time is briefly discussed. The spinor interaction with the new gauge field is then analyzed assuming the time gauge and stationa

Valentin Bonzom, Etera R. Livine

We study an Immirzi-like ambiguity in three-dimensional quantum gravity. It shares some features with the Immirzi parameter of four-dimensional loop quantum gravity: it does not affect the equations of motion, but modifies the Poisson brackets and the constraint algebra at the canonical level. We focus on the length operator and show how to define it through

Scipio Cuccagna

We introduce a new notion of linear stability for standing waves of the nonlinear Schrödinger equation (NLS) which requires not only that the spectrum of the linearization be real, but also that the generalized kernel be not degenerate and that the signature of all the positive eigenvalues be positive. We prove that excited states of the NLS are not linearly

Jian-Hua He, Bin Wang

We examine the effects of possible phenomenological interactions between dark energy and dark matter on cosmological parameters and their efficiency in solving the coincidence problem. We work with two simple parameterizations of the dynamical dark energy equation of state and the constant dark energy equation of state. Using observational data coming from t

Florent Benaych-Georges, Ion Nechita

In this paper, we generalize a permutation model for free random variables which was first proposed by Biane in \cite{biane}. We also construct its classical probability analogue, by replacing the group of permutations with the group of subsets of a finite set endowed with the symmetric difference operation. These constructions provide new discrete approxima

A. Krikun

In this paper we study the chiral symmetry breaking in the hard wall AdS/QCD model. We solve the equations of motion up to the second order at large momentum and obtain the first few terms in the expansion of the &#34;left-right&#34; correlator, which is the measure of symmetry breaking. We study the dependence on AdS radius to get the result as the series i

Xiangqian Guo, Rencai Lu, Kaiming Zhao

The loop-Virasoro algebra is the Lie algebra of the tensor product of the Virasoro algebra and the Laurent polynomial algebra. This paper classifies irreducible Harish-Chandra modules over the loop-Virasoro algebra, which turn out to be highest weight modules, lowest weight modules and evaluation modules of the intermediate series (all wight spaces are 1-dim

Kazuo Ghoroku, Masafumi Ishihara

We study baryons in SU(N) gauge theories, according to the gauge/string correspondence based on IIB string theory. The D5 brane, in which $N$ fundamental strings are dissolved as a color singlet, is introduced as the baryon vertex, and its configurations are studied. We find point- and split-type of vertex. In the latter case, two cusps appears and they are

Jan E. Aman, Stefan Aminneborg, Ingemar Bengtsson, Narit Pidokrajt

In 3+1 dimensions there are anti-de quotients which are black holes with toroidal event horizons. By analytic continuation of the Schwarzschild-anti-de Sitter solution (and appropriate identifications) one finds two one parameter families of spacetimes that contain these quotient black holes. One of these families consists of B-metrics (&#34;bubbles of nothi

B. Keilhauer, J. Bluemer, R. Engel, H. O. Klages

Fluorescence light is induced by extensive air showers while developing in the Earth&#39;s atmosphere. The number of emitted fluorescence photons depends on the conditions of the air and on the energy deposited by the shower particles at every stage of the development. In a previous model calculation, the pressure and temperature dependences of the fluoresce

Richard Easther, John T. Giblin, Eugene A. Lim, Wan-Il Park

We consider the impact of thermal inflation -- a short, secondary period of inflation that can arise in supersymmetric scenarios -- on the stochastic gravitational wave background. We show that while the primordial inflationary gravitational wave background is essentially unchanged at CMB scales, it is massively diluted at solar system scales and would be un

P. V. Dong, H. N. Long

We show that in the framework of the 3-3-1 model with right-handed neutrinos, small neutrino masses and large lepton flavor violating processes such as μ\to 3e and μ\to eγcan be obtained by just introducing an additional Higgs sextet. In the limit of vanishing of the Yukawa interaction among Higgs and lepton triplets (h^ν= 0), the decay μ\to 3e strongly depe

Constantinos Daskalakis, Elchanan Mossel, Sebastien Roch

We introduce a new phylogenetic reconstruction algorithm which, unlike most previous rigorous inference techniques, does not rely on assumptions regarding the branch lengths or the depth of the tree. The algorithm returns a forest which is guaranteed to contain all edges that are: 1) sufficiently long and 2) sufficiently close to the leaves. How much of the

Chandrasekhar Chatterjee, Sunandan Gangopadhyay, Arindam Ghosh Hazra, Saurav Samanta

The appearance of non(anti)commutativity in superstring theory, satisfying the Neveu-Schwarz boundary conditions is discussed in this paper. Both an open free superstring and also one moving in a background antisymmetric tensor field are analyzed to illustrate the point that string non(anti)commutativity is a consequence of the nontrivial boundary conditions

M. Kriener, M. Braden, H. Kierspel, D. Senff

We report thermal-expansion, lattice-constant, and specific-heat data of the series La_1-xA_xCoO_3 for 0<= x <= 0.30 with A = Ca, Sr, and Ba. For the undoped compound LaCoO_3 the thermal-expansion coefficient alpha(T) exhibits a pronounced maximum around T=50K caused by a temperature-driven spin-state transition from a low-spin state of the Co^{3+$ ions at l

D. H. Phong, Jacob Sturm

An introduction is provided to some current research trends in stability in geometric invariant theory and the problem of Kaehler metrics of constant scalar curvature. Besides classical notions such as Chow-Mumford stability, the emphasis is on several new stability conditions, such as K-stability, Donaldson&#39;s infinite-dimensional GIT, and conditions on

Brian C. Hart

Clusters of galaxies are the largest gravitationally-bound objects in the Universe, having diameters on order of Mpc. Our work asked whether their shapes (morphologies) change over time as the Universe ages. We observed a sample of 165 galaxy clusters, at 0.1 < z < 1.3. A variety of measures were used to quantify the shapes of galaxy clusters. Archive observ

Xinping Xu, Feng Liu

In this paper, we consider continuous-time quantum walks (CTQWs) on one-dimension ring lattice of N nodes in which every node is connected to its 2m nearest neighbors (m on either side). In the framework of the Bloch function ansatz, we calculate the spacetime transition probabilities between two nodes of the lattice. We find that the transport of CTQWs betw

Donald F. Figer

Over the past ten years, there has been a revolution in our understanding of massive young stellar clusters in the Galaxy. Initially, there were no known examples having masses $>10^4$, yet we now know that there are at least a half dozen such clusters in the Galaxy. In all but one case, the masses have been determined through infrared observations. Several

S. Bastrukov, H-K. Chang, G. -T. Chen, I. Molodtsova

The Newtonian solid-mechanical theory of non-compressional spheroidal and torsional nodeless elastic vibrations in the homogenous crust model of a quaking neutron star is developed and applied to the modal classification of the quasi-periodic oscillations (QPOs) of X-ray luminosity in the aftermath of giant flares in SGR 1806-20 and SGR 1900+14. Particular a

S. Kuroiwa, Y. Saura, J. Akimitsu, M. Hiraishi

A complex structure of the superconducting order parameter in $Ln_2$C$_3$ ($Ln$ = La, Y) is demonstrated by muon spin relaxation ($μ$SR) measurements in their mixed state. The muon depolarization rate [$σ_{\rm v}(T)$] exhibits a characteristic temperature dependence that can be perfectly described by a phenomenological double-gap model for nodeless supercond

Yassmin Ansari, Viswanath Ramakrishna

This work provides a quaternioinc reprsentation for real symplectic matrices in dimension four, analogous to the pair of unit quaternions representation for special orthogonal matrices. In the process of finding formulae for this representation in terms of the entries of the symplectic matrix being thereby represented, it shows how to compute the polar decom

Elena Poletaeva

We give a general construction of realizations of the contact superconformal algebras $K(2)$ and $\hat{K}&#39;(4)$, and the exceptional superconformal algebra $CK_6$ as subsuperalgebras of matrices over a Weyl algebra of size $2^N\times 2^N$, where $N = 1, 2$ and $3$. We show that there is no such a realization for $K(2N)$, if $N\geq 4$.

M. Levi, S. Tabachnikov

The model of a bicycle is a unit segment AB that can move in the plane so that it remains tangent to the trajectory of point A (the rear wheel is fixed on the bicycle frame); the same model describes the hatchet planimeter. The trajectory of the front wheel and the initial position of the bicycle uniquely determine its motion and its terminal position; the m

Baruch Vainas

A composite, exponential relaxation function, modulated by a periodic component, was used to fit to an experimental time series of blood glucose levels. The 11 parameters function that allows for the detection of a possible rhythm transition was fitted to the experimental time series using a genetic algorithm. It has been found that the relaxation from a hyp

Harm Derksen

To every subspace arrangement X we will associate symmetric functions P[X] and H[X]. These symmetric functions encode the Hilbert series and the minimal projective resolution of the product ideal associated to the subspace arrangement. They can be defined for discrete polymatroids as well. The invariant H[X] specializes to the Tutte polynomial T[X]. Billera,

David B. Chandler, Peter Sin, Qing Xiang

We study the permutation action of a finite symplectic group of characteristic 2 on the set of subspaces of its standard module which are either totally isotropic or else complementary to totally isotropic subspaces with respect to the alternating form. A general formula is obtained for the 2-rank of the incidence matrix for the inclusion of one-dimensional

Arunav Kundu, Stephen E. Zepf, Thomas J. Maccarone

Studies of nearby elliptical and S0 galaxies reveal that roughly half of the low mass X-ray binaries (LMXBs), which are luminous tracers of accreting neutron star or black hole systems, are in clusters. There is a surprising tendency of LMXBs to be preferentially associated with metal-rich globular clusters (GCs), with metal-rich GCs hosting three times as m

I. Georgantopoulos, P. Tzanavaris

We compile one of the largest ever samples to probe the X-ray normal galaxy luminosity function and its evolution with cosmic time. In particular, we select 207 galaxies (106 late and 101 early-type systems) from the Chandra Deep Field North and South surveys, the Extended Chandra Deep Field South and the XBOOTES survey. We derive the luminosity function sep

S. Pasquali, A. C. Maggs

We study numerically the Casimir interaction between dielectrics in both two and three dimensions. We demonstrate how sparse matrix factorizations enable one to study torsional interactions in three dimensions. In two dimensions we study the full cross-over between non-retarded and retarded interactions as a function of separation. We use constrained factori