35,096 research outputs found

    The interplay between high energy physics and cosmology: an example

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    Cosmology and high energy physics are two closely connected areas. In this lecture I present an example of their rich interplay.Comment: Invited talk at the DPU workshop: The density fluctuations in the Universe: Beyond the inflationary paradigm (Dimokritos, Athens 2004) (see http://physics.ntua.gr/dpu/). 8 two column page

    Randomized Dynamical Decoupling Techniques for Coherent Quantum Control

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    The need for strategies able to accurately manipulate quantum dynamics is ubiquitous in quantum control and quantum information processing. We investigate two scenarios where randomized dynamical decoupling techniques become more advantageous with respect to standard deterministic methods in switching off unwanted dynamical evolution in a closed quantum system: when dealing with decoupling cycles which involve a large number of control actions and/or when seeking long-time quantum information storage. Highly effective hybrid decoupling schemes, which combine deterministic and stochastic features are discussed, as well as the benefits of sequentially implementing a concatenated method, applied at short times, followed by a hybrid protocol, employed at longer times. A quantum register consisting of a chain of spin-1/2 particles interacting via the Heisenberg interaction is used as a model for the analysis throughout.Comment: 7 pages, 2 figures. Replaced with final version. Invited talk delivered at the XXXVI Winter Colloquium on the Physics of Quantum Electronics, Snowbird, Jan 2006. To be published in J. Mod. Optic

    A Denotational Semantics for First-Order Logic

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    In Apt and Bezem [AB99] (see cs.LO/9811017) we provided a computational interpretation of first-order formulas over arbitrary interpretations. Here we complement this work by introducing a denotational semantics for first-order logic. Additionally, by allowing an assignment of a non-ground term to a variable we introduce in this framework logical variables. The semantics combines a number of well-known ideas from the areas of semantics of imperative programming languages and logic programming. In the resulting computational view conjunction corresponds to sequential composition, disjunction to ``don't know'' nondeterminism, existential quantification to declaration of a local variable, and negation to the ``negation as finite failure'' rule. The soundness result shows correctness of the semantics with respect to the notion of truth. The proof resembles in some aspects the proof of the soundness of the SLDNF-resolution.Comment: 17 pages. Invited talk at the Computational Logic Conference (CL 2000). To appear in Springer-Verlag Lecture Notes in Computer Scienc

    The Phenomenology of Glueball and Hybrid Mesons

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    The existence of non-q\bar{q} hadrons such as glueballs and hybrids is one of the most important qualitative questions in QCD. The COMPASS experiment offers the possibility to unambiguously identify such states and map out the glueball and hybrid spectrum. In this review I discuss the expected properties of glueballs and hybrids and how they might be produced and studied by the COMPASS collaboration.Comment: Invited talk at the Workshop on Future Physics @ COMPASS, CERN, Sept 26-27 2002. 12 pages, 6 figures. Uses cernrep.cls (included

    Paper Abstracts (2015)

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    Twentieth Conference of the Association of Christians in the Mathematical Science

    Numeration Systems: a Link between Number Theory and Formal Language Theory

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    We survey facts mostly emerging from the seminal results of Alan Cobham obtained in the late sixties and early seventies. We do not attempt to be exhaustive but try instead to give some personal interpretations and some research directions. We discuss the notion of numeration systems, recognizable sets of integers and automatic sequences. We briefly sketch some results about transcendence related to the representation of real numbers. We conclude with some applications to combinatorial game theory and verification of infinite-state systems and present a list of open problems.Comment: 21 pages, 3 figures, invited talk DLT'201

    Thoughts about a General Theory of Influence in a DIME/PMESII/ASCOP/IRC2 Model

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    The leading question of this paper is: “How would influence warfare (“iWar”) work and how can we simulate it?” The paper discusses foundational aspects of a theory and model of influence warfare by discussing a framework built along the DIME/PMESII/ASCOP dimension forming a prism with three axes. The DIME concept groups the many instruments of power a nation state can muster into four categories: Diplomacy, Information, Military and Economy. PMESII describes the operational environment in six domains: Political, Military, Economic, Social, Information and Infrastructure. ASCOPE is used in counter insurgency (COIN) environments to analyze the cultural and human environment (aka the “human terrain”) and encompasses Areas, Structures, Capabilities, Organization, People and Events. In addition, the model reflects about aspects of information collection requirements (ICR) and information capabilities requirements (ICR) - hence DIME/PMESII/ASCOP/ICR2. This model was developed from an influence wargame that was conducted in October 2018. This paper introduces basic methodical questions around model building in general and puts a special focus on building a framework for the problem space of influence/information/hybrid warfare takes its shape in. The article tries to describe mechanisms and principles in the information/influence space using cross discipline terminology (e.g. physics, chemistry and literature). On a more advanced level this article contributes to the Human, Social, Culture, Behavior (HSCB) models and community. One goal is to establish an academic, multinational and whole of government influence wargamer community. This paper introduces the idea of the perception field understood as a molecule of a story or narrative that influences an observer. This molecule can be drawn as a selection of vectors that can be built inside the DIME/PMESII/ASCOP prism. Each vector can be influenced by a shielding or shaping action. These ideas were explored in this influence wargame
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