The Wilson loop from a Dyson equation

The Dyson equation proposed for planar temporal Wilson loops in the context of supersymmetric gauge theories is critically analysed thereby exhibiting its ingredients and approximations involved. We reveal its limitations and identify its range of applicability in non-supersymmetric gauge theories. In particular, we show that this equation is applicable only to strongly asymmetric planar Wilson loops (consisting of a long and a short pair of loop segments) and as a consequence the Wilsonian potential can be extracted only up to intermediate distances. By this equation the Wilson loop is exclusively determined by the gluon propagator. We solve the Dyson equation in Coulomb gauge for the temporal Wilson loop with the instantaneous part of the gluon propagator and for the spatial Wilson loop with the static gluon propagator obtained in the Hamiltonian approach to continuum Yang-Mills theory and on the lattice. In both cases we find a linearly rising color potential.Comment: 12 pages, 7 figure

High stability amplifier

An electrical RF signal amplifier for providing high temperature stability and RF isolation and comprised of an integrated circuit voltage regulator, a single transistor, and an integrated circuit operational amplifier mounted on a circuit board such that passive circuit elements are located on side of the circuit board while the active circuit elements are located on the other side is described. The active circuit elements are embedded in a common heat sink so that a common temperature reference is provided for changes in ambient temperature. The single transistor and operational amplifier are connected together to form a feedback amplifier powered from the voltage regulator with transistor implementing primarily the desired signal gain while the operational amplifier implements signal isolation. Further RF isolation is provided by the voltage regulator which inhibits cross-talk from other like amplifiers powered from a common power supply. Input and output terminals consisting of coaxial connectors are located on the sides of a housing in which all the circuit components and heat sink are located

THEORETICAL INVESTIGATION OF UNSTEADY DIFFUSION WITH RECOMBINATION IN A TERNARY MIXTURE OF DIATOMIC MOLECULES, DISSOCIATED ATOMS, AND AN INERT GAS

Unsteady diffusion with recombination in ternary mixture of diatomic molecules, dissociated atoms, and an inert ga

Two-Point Functions of Coulomb Gauge Yang-Mills Theory

The functional approach to Coulomb gauge Yang-Mills theory is considered within the standard, second order, formalism. The Dyson-Schwinger equations and Slavnov-Taylor identities concerning the two-point functions are derived explicitly and one-loop perturbative results are presented.Comment: 12 pages, no figure

The DaVinci Center For Community Progress: Making The Community More Liveable

There are many innovations, projects, and programs which can make a community more liveable. The elements that they have in common are 1) the vision of the founder (or co-founders), 2) a dedicated connection to the community and populations in which the innovation or project is located, 3) the necessary social skills and contacts of the founder(s) and other key people involved in the innovation, 4) hard work, and 5) funding sources that continue over time to keep the services (or project) going, as well as to add services as needs change. The DaVinci Center for Community Progress, in Providence, RI, is an excellent example of how to make a community more liveable for diverse populations for whom it has provided services since it opened its doors in 1972. The DaVinci Center is a multi-purpose facility based on the settlement house model in regard to many of the services it offers. It differs from the settlement house model in that the DaVinci Center staff does not live at the Center. The Center was co-founded by John DeLuca who has also served as its longtime Executive Director. The content for this article was gathered, in part, through a lengthy, structured interview both authors conducted with John at the Center, a review of written materials produced by the Center, and information provided on the Center’s website

Alternating, private alternating, and quantum alternating realtime automata

We present new results on realtime alternating, private alternating, and quantum alternating automaton models. Firstly, we show that the emptiness problem for alternating one-counter automata on unary alphabets is undecidable. Then, we present two equivalent definitions of realtime private alternating finite automata (PAFAs). We show that the emptiness problem is undecidable for PAFAs. Furthermore, PAFAs can recognize some nonregular unary languages, including the unary squares language, which seems to be difficult even for some classical counter automata with two-way input. Regarding quantum finite automata (QFAs), we show that the emptiness problem is undecidable both for universal QFAs on general alphabets, and for alternating QFAs with two alternations on unary alphabets. On the other hand, the same problem is decidable for nondeterministic QFAs on general alphabets. We also show that the unary squares language is recognized by alternating QFAs with two alternations

Variational solution of the Yang-Mills Schr\"odinger equation in Coulomb gauge

The Yang-Mills Schr\"odinger equation is solved in Coulomb gauge for the vacuum by the variational principle using an ansatz for the wave functional, which is strongly peaked at the Gribov horizon. A coupled set of Schwinger-Dyson equations for the gluon and ghost propagators in the Yang-Mills vacuum as well as for the curvature of gauge orbit space is derived and solved in one-loop approximation. We find an infrared suppressed gluon propagator, an infrared singular ghost propagator and a almost linearly rising confinement potential.Comment: 24 pages, revtex, 13 figure

Magnetic Monopoles, Center Vortices and Topology of Gauge Fields

The topological properties of magnetic monopoles and center vortices arising, respectively, in Abelian and center gauges are studied in continuum Yang-Mills Theory. For this purpose the continuum analog of the maximum center gauge is constructed.Comment: talk presented at LATTICE99(topology) at Pisa, Italy, 3 page