Long Range Forces from Pseudoscalar Exchange

Using dispersion theoretic techniques, we consider coherent long range forces arising from double pseudoscalar exchange among fermions. We find that Yukawa type coupling leads to $1/r^3$ spin independent attractive potentials whereas derivative coupling renders $1/r^5$ spin independent repulsive potentials.Comment: 27 pages, REVTeX, 3 figures included using epsfi

Programmable telemetry system Patent

Time division multiplexed telemetry transmitting system controlled by programmed memor

Effective Non-Hermitian Hamiltonians for Studying Resonance Statistics in Open Disordered Systems

We briefly discuss construction of energy-dependent effective non-hermitian hamiltonians for studying resonances in open disordered systemsComment: Latex, 20 pages, 1 fig. Expanded version of a talk at the Workshop on Pseudo-Hermitian Hamiltonians in Quantum Physics IX, June 21-24 2010, Zhejiang University, Hangzhou, China. Accepted for publication in the Internationa Journal of Theoretical Physics (Springer Verlag

Effects of Bose-Einstein Condensation on forces among bodies sitting in a boson heat bath

We explore the consequences of Bose-Einstein condensation on two-scalar-exchange mediated forces among bodies that sit in a boson gas. We find that below the condensation temperature the range of the forces becomes infinite while it is finite at temperatures above condensation.Comment: 10 pages, 2 figure

Addendum to Finite-size effects on multibody neutrino exchange

The interaction energy of the neutrons due to massless neutrino exchange in a neutron star has recently been proved, using an effective theory, to be extremely small and infrared-safe. Our comment here is of conceptual order: two approaches to compute the total interaction energy density have recently been proposed. Here, we study the connection between these two approaches. From CP invariance, we argue that the resulting interaction energy has to be even in the parameter $b=-G_F n_n /\sqrt{2}$, which expresses the static neutrino potential created by a neutron medium of density $n_n$.Comment: Latex file (Revtex), 9 pages, 1 figure, one reference change

Dynamical Generation of Extended Objects in a 1+11+1 Dimensional Chiral Field Theory: Non-Perturbative Dirac Operator Resolvent Analysis

We analyze the $1+1$ dimensional Nambu-Jona-Lasinio model non-perturbatively. In addition to its simple ground state saddle points, the effective action of this model has a rich collection of non-trivial saddle points in which the composite fields \sigx=\lag\bar\psi\psi\rag and \pix=\lag\bar\psi i\gam_5\psi\rag form static space dependent configurations because of non-trivial dynamics. These configurations may be viewed as one dimensional chiral bags that trap the original fermions (``quarks") into stable extended entities (``hadrons"). We provide explicit expressions for the profiles of these objects and calculate their masses. Our analysis of these saddle points is based on an explicit representation we find for the diagonal resolvent of the Dirac operator in a \{\sigx, \pix\} background which produces a prescribed number of bound states. We analyse in detail the cases of a single as well as two bound states. We find that bags that trap $N$ fermions are the most stable ones, because they release all the fermion rest mass as binding energy and become massless. Our explicit construction of the diagonal resolvent is based on elementary Sturm-Liouville theory and simple dimensional analysis and does not depend on the large $N$ approximation. These facts make it, in our view, simpler and more direct than the calculations previously done by Shei, using the inverse scattering method following Dashen, Hasslacher, and Neveu. Our method of finding such non-trivial static configurations may be applied to other $1+1$ dimensional field theories

Long range neutrino forces in the cosmic relic neutrino background

Neutrinos mediate long range forces among macroscopic bodies in vacuum. When the bodies are placed in the neutrino cosmic background, these forces are modified. Indeed, at distances long compared to the scale $T^{-1}$, the relic neutrinos completely screen off the 2-neutrino exchange force, whereas for small distances the interaction remains unaffected.Comment: 8 pages, 2 figure

Scaling and Universality of the Complexity of Analog Computation

We apply a probabilistic approach to study the computational complexity of analog computers which solve linear programming problems. We analyze numerically various ensembles of linear programming problems and obtain, for each of these ensembles, the probability distribution functions of certain quantities which measure the computational complexity, known as the convergence rate, the barrier and the computation time. We find that in the limit of very large problems these probability distributions are universal scaling functions. In other words, the probability distribution function for each of these three quantities becomes, in the limit of large problem size, a function of a single scaling variable, which is a certain composition of the quantity in question and the size of the system. Moreover, various ensembles studied seem to lead essentially to the same scaling functions, which depend only on the variance of the ensemble. These results extend analytical and numerical results obtained recently for the Gaussian ensemble, and support the conjecture that these scaling functions are universal.Comment: 22 pages, latex, 12 eps fig

Langual : un langage international pour la description structurée des aliments = Langual : an international language for the structured description of foods

L'article traite de l'organisation des nouvelles banques de données sur la composition des aliments en s'appuyant sur l'exemple de la banque française REGAL développée au CIQUAL. La codification des nutriments et les principes de standardisation des formules de calcul de certains nutriments sont évoqués. L'identification précise des aliments grâce à une description claire, complète, scientifique et se prêtant à des vérifications automatisées de similitude, est indispensable pour assurer de façon cohérente des transferts de données entre banques de différents pays. Langual, système international de codification descriptive des aliments permet une telle identification. Chaque aliment à coder est décrit par un ensemble des descripteurs standardisés, eux-mêmes regroupés en facettes. Chaque facette représente un sous-ensemble de caractéristiques comme l'origine biologique, les traitements technologiques, les méthodes de conservation et de cuisson, qui spécifient la qualité nutritionnelle et/ou hygiénique d'un aliment. (Résumé d'auteur

Validated data banks on food composition : concepts for modeling information

L'intérêt croissant pour la composition des aliments a conduit plusieurs pays à se doter de banque de données sur la composition des aliments. Ces banques sont des outils pour le contrôle de la qualité des aliments et pour la conduite des politiques alimentaires. L'article traite de la conception, de la structure, de la gestion et du fonctionnement de la banque de données française REGAL. Le système de description codifiée des aliments LANGUAL est, en particulier, présenté. Comme REGAL, les banques de données peuvent également prendre en compte la réglementation relative aux aliments ; il est aussi possible de leur incorporer des systèmes-experts. (Résumé d'auteur