Unquenched quark propagator in Landau gauge

We present an unquenched calculation of the quark propagator in Landau gauge with 2+1 flavors of dynamical quarks. We use configurations generated with an improved staggered (``Asqtad'') action by the MILC collaboration. This quark action has been seen to have excellent rotational symmetry and scaling properties in the quenched quark propagator. Quenched and dynamical calculations are performed on a $20^3\times 64$ lattice with a nominal lattice spacing of $a = 0.125$ fm. The matched quenched and dynamical lattices allow us to investigate the relatively subtle sea quark effects, and even in the quenched case the physical volume of these lattices gives access to lower momenta than our previous study. We calculate the quark mass function and renormalization function for a variety of valence and sea quark masses.Comment: 7 pages, 6 figure

Virtualization for a Network Processor Runtime System

The continuing ossification of the Internet is slowing the pace of network innovation. Network diversification presents one solution to this problem, by virtualizing the network at multiple layers. Diversified networks consist of a shared physical substrate, virtual routers (metarouters), and virtual links (metalinks). Virtualizing routers enables smooth and incremental upgrades to new network services. Our current priority for a diversified router prototype is to enable reserved slices of the network for researchers to perform repeatable, high-speed network experiments. General-purpose processors have well established techniques for virtualization, but do not scale efficiently to multi-gigabit speeds. To achieve these speeds, we employ network processors (NPs), typically consisting of multicore, multi-threaded processors with asymmetric, heterogeneous memories. The complexity and lack of hardware thread isolation in NP’s, combined with a lack of simple programming models, creates numerous challenges for effective sharing between metarouters. In this paper, we detail strategies for enabling NP virtualization at the link, memory, and processor levels, to better enable a research infrastructure for network innovation

Quark propagator from an improved staggered action in Laplacian and Landau gauges

Studies of gauge dependent quantities are afflicted with Gribov copies, but Laplacian gauge fixing provides one possible solution to this problem. We present results for the lattice quark propagator in both Landau and Laplacian gauges using standard and improved staggered quark actions. The standard Kogut-Susskind action has errors of \oa{2} while the improved ``Asqtad'' action has \oa{4}, \oag{2}{2} errors and this improvement is seen in the quark propagator. We demonstrate the application of tree-level corrections to these actions and see that Landau and Laplacian gauges produce very similar results. In addition, we test an ansatz for the quark mass function, with promising results. In the chiral limit, the infrared quark mass, $M(q^2 = 0)$ is found to be $260\pm 20$ MeV.Comment: 5 pages, 8 figs., Talk given at LHP workshop, Cairn

New Producer Contract Terms and Uncertainty: Lessons From the Recent Past

The petroleum industry is volatile, and governments in “new producer” countries have operated at a significant information disadvantage when negotiating with international oil companies. This challenge is growing today; new producer countries face intensifying questions around whether to offer fiscal incentives to maintain investment in the face of 1) the pandemic-induced volatility in oil prices and 2) long-term questions about the future of the industry in the face of the climate crisis and the global energy transition. This confluence of short-term and long-term uncertainty is prompting a reexamination of the narrative that once took hold in many new producer countries. The traditional story was one of linear progression from being non-producers to small levels of production to ultimately having oil and gas become a major economic contributor over the long term. This notion of progression was associated with a commonly held theory: After a country’s first major discovery, the geological risk that wells will be dry was expected to decrease. Countries could therefore shift from a position of having to grant tax breaks (and other concessions) to international investors, to taking a tougher stance in laws and negotiations for new projects going forward. In this paper, co-authored with NRGI we examine whether this theory has been borne out in practice and make recommendations to support new producers in their navigation of the uncertainty associated with the energy transition

Bibliothèque 2.0 – tout va-t-il changer?

Following up their article „Bibliothek 2.0 – Die Zukunft der Bibliothek?“ („Library 2.0 – The future of the library?“) (2006), Patrick Danowski and Lambert Heller, responsible for the main focus of this issue, give an outline of some recently discussed library 2.0 topics, especially in respect to the professional community in germany. Some characteristic questions and problems of the development, opening and networking of library Services and information are mentioned.En référence à leur article „Bibliothèque 2.0 – l‘avenir de la bibliothèque?“ (2006), Patrick Danowski et Lambert Heller, responsables de la présente édition, donnent un aperçu de l‘état actuel de la discussion sur les différents aspects de la Bibliothèque 2.0 en tenant particulièrement compte de l‘opinion exprimée par les spécialistes en Allemagne. Ils évoquent certains points et problèmes caractéristiques concernant l‘évolution, l‘ouverture et la mise en réseau des services et des informations propres aux bibliothèques.Anknüpfend an ihren Aufsatz „Bibliothek 2.0 – Die Zukunft der Bibliothek?“ (2006) geben Patrick Danowski und Lambert Heller, verantwortlich für das Schwerpunktthema der vorliegenden Ausgabe, einen Überblick über den erreichten Diskussionsstand über verschiedene Teilaspekte der Bibliothek 2.0 unter besonderer Berücksichtigung der deutschen Fachöffentlichkeit. Einige charakteristische Fragen und Probleme der Weiterentwicklung, Öffnung und Vernetzung bibliothekarischer Dienste und Informationen werden angesprochen