Multiplier Sequences for Simple Sets of Polynomials

In this paper we give a new characterization of simple sets of polynomials B with the property that the set of B-multiplier sequences contains all Q-multiplier sequence for every simple set Q. We characterize sequences of real numbers which are multiplier sequences for every simple set Q, and obtain some results toward the partitioning of the set of classical multiplier sequences

Resonant excitations of the 't Hooft-Polyakov monopole

The spherically symmetric magnetic monopole in an SU(2) gauge theory coupled to a massless Higgs field is shown to possess an infinite number of resonances or quasinormal modes. These modes are eigenfunctions of the isospin 1 perturbation equations with complex eigenvalues, $E_n=\omega_n-i\gamma_n$, satisfying the outgoing radiation condition. For $n\to\infty$, their frequencies $\omega_n$ approach the mass of the vector boson, $M_W$, while their lifetimes $1/\gamma_n$ tend to infinity. The response of the monopole to an arbitrary initial perturbation is largely determined by these resonant modes, whose collective effect leads to the formation of a long living breather-like excitation characterized by pulsations with a frequency approaching $M_W$ and with an amplitude decaying at late times as $t^{-5/6}$.Comment: 4 page

Eclipse timing variation analysis of OGLE-IV eclipsing binaries towards the Galactic Bulge – I. Hierarchical triple system candidates

We report a study of the eclipse timing variation (ETV) of short period ($P_1\le 6^d$) eclipsing binaries (EB) monitored during the photometric survey OGLE-IV. From the 425\,193 EBs we selected approximately 80\,000 binaries that we found suitable for further examination. Among them we identified 992 potential hierarchical triple (or multiple ) system candidates exhibiting light-travel-time effect (LTTE). Besides, we obtained the orbital parameters of these systems and carried out statistical analyses on the properties of these candidates. We found that (i) there is a significant lack of triple systems where the outer period is less than 500 days; (ii) the distribution of the outer eccentricities has a maximum around $e_2\approx0.3$; (iii) the outer mass ratio calculated from an estimated minimum mass of the third component is lower than $q_2\sim 0.5$ for the majority of the sample. We also present some systems that deserve special attention. (i) There are four candidates that show double periodic ETV, which we explain by the presence of a fourth companion. (ii) For two systems the perturbations of the third component are also found to be significant therefore we give a combined dynamical and LTTE ETV solution. (iii) For one system the third component is found to be probably in the substellar mass domain.Comment: Accepted for publication in MNRA

On the compatibility of a flux transport dynamo with a fast tachocline scenario

The compatibility of the fast tachocline scenario with a flux transport dynamo model is explored. We employ a flux transport dynamo model coupled with simple feedback formulae relating the thickness of the tachocline to the amplitude of the magnetic field or to the Maxwell stress. The dynamo model is found to be robust against the nonlinearity introduced by this simplified fast tachocline mechanism. Solar-like butterfly diagrams are found to persist and, even without any parameter fitting, the overall thickness of the tachocline is well within the range admitted by helioseismic constraints. In the most realistic case of a time and latitude dependent tachocline thickness linked to the value of the Maxwell stress, both the thickness and its latitude dependence are in excellent agreement with seismic results. In the nonparametric models, cycle related temporal variations in tachocline thickness are somewhat larger than admitted by helioseismic constraints; we find, however, that introducing a further parameter into our feedback formula readily allows further fine tuning of the thickness variations.Comment: Accepted in Solar Physic

Benefits of a marketing cooperative in transition agriculture: Mórakert purchasing and service co-operative

The paper analyses the potential benefits of marketing cooperatives in Hungary, employing a transaction cost economics framework. We found that the purchased quantity, the existence of contracts, flexibility and trust are the most important factors farmers consider when selling their products via a cooperative. The most striking result is that diversification has positive influences on the share of cooperatives in farmers’ sale. Furthermore, farmers with larger bargaining power have less willingness to sell their product to the cooperative. Surprisingly, asset specificity has rather negative effects on the share of cooperatives in members’ sales

The mass gap and vacuum energy of the Gross-Neveu model via the 2PPI expansion

We introduce the 2PPI (2-point-particle-irreducible) expansion, which sums bubble graphs to all orders. We prove the renormalizibility of this summation. We use it on the Gross-Neveu model to calculate the mass gap and vacuum energy. After an optimization of the expansion, the final results are qualitatively good.Comment: 14 pages,19 eps figures, revtex

Dynamical mass generation in quantum field theory : some methods with application to the Gross-Neveu model and Yang-Mills theory

We introduce some techniques to investigate dynamical mass generation. The Gross-Neveu model (GN) is used as a toy model, because the GN mass gap is exactly known, making it possible to check reliability of the various methods. Very accurate results are obtained. Also application to SU(N) Yang-Mills (YM) is discussed.Comment: 8 LaTeX2e pages, uses Kluwer class file crckbked.cls. Kluwer package included. To appear in: Proceedings of the NATO Advanced Research Workshop on "Confinement, Topology, and other Non-Perturbative Aspects of QCD", Stara Lesna, Slovakia, 21-27 jan 200

A search for tight hierarchical triple systems amongst the eclipsing binaries in the CoRoT fields

We report a comprehensive search for hierarchical triple stellar system candidates amongst eclipsing binaries (EB) observed by the CoRoT spacecraft. We calculate and check eclipse timing variation (ETV) diagrams for almost 1500 EBs in an automated manner. We identify five relatively short-period Algol systems for which our combined light curve and complex ETV analyses (including both the light-travel time effect and short-term dynamical third-body perturbations) resulted in consistent third-body solutions. The computed periods of the outer bodies are between 82 and 272 days, (with an alternative solution of 831 days for one of the targets). We find that the inner and outer orbits are near coplanar in all but one case. The dynamical masses of the outer subsystems determined from the ETV analyses are consistent with both the results of our light curve analyses and the spectroscopic information available in the literature. One of our candidate systems exhibits outer eclipsing events as well, the locations of which are in good agreement with the ETV solution. We also report another certain triply eclipsing triple system which, however, is lacking a reliable ETV solution due to the very short time range of the data, and four new blended systems (composite light curves of 2 eclipsing binaries each), where we cannot decide whether the components are gravitationally binded or not. Amongst these blended systems we identify the longest period and highest eccentricity eclipsing binary in the entire CoRoT sample

Some Recent Developments on Kink Collisions and Related Topics

We review recent works on modeling of dynamics of kinks in 1+1 dimensional $\phi^4$ theory and other related models, like sine-Gordon model or $\phi^6$ theory. We discuss how the spectral structure of small perturbations can affect the dynamics of non-perturbative states, such as kinks or oscillons. We describe different mechanisms, which may lead to the occurrence of the resonant structure in the kink-antikink collisions. We explain the origin of the radiation pressure mechanism, in particular, the appearance of the negative radiation pressure in the $\phi^4$ and $\phi^6$ models. We also show that the process of production of the kink-antikink pairs, induced by radiation is chaotic.Comment: 26 pages, 9 figures; invited chapter to "A dynamical perspective on the {\phi}4 model: Past, present and future", Eds. P.G. Kevrekidis and J. Cuevas-Maraver; Springer book class with svmult.cls include

Chern-Simons Solitons, Toda Theories and the Chiral Model

The two-dimensional self-dual Chern--Simons equations are equivalent to the conditions for static, zero-energy solutions of the $(2+1)$-dimensional gauged nonlinear Schr\"odinger equation with Chern--Simons matter-gauge dynamics. In this paper we classify all finite charge $SU(N)$ solutions by first transforming the self-dual Chern--Simons equations into the two-dimensional chiral model (or harmonic map) equations, and then using the Uhlenbeck--Wood classification of harmonic maps into the unitary groups. This construction also leads to a new relationship between the $SU(N)$ Toda and $SU(N)$ chiral model solutions