65,877 research outputs found
Particle Physics as Representations of the Poincare Algebra
Eugene Wigner showed already in 1939 that the elementary particles are
related to the irreducible representations of the Poincare algebra. In the
light-cone frame formulation of quantum field theory one can extend these
representations to depend also on a coupling constant. The representations then
become non-linear and contain the interaction terms which are shown to have
strong uniqueness. Extending the algebra to supersymmetry it is shown that two
field theories stick out, N=4 Yang-Mills and N=8 Supergravity and their higher
dimensional analogues. I also discuss string theory from this starting point.Comment: Lecture presented at the Poincare Symposium held in Brussels on
October 8-9, 200
Monte Carlo Generators
The structure of events in high-energy collisions is complex and not
predictable from first principles. Event generators allow the problem to be
subdivided into more manageable pieces, some of which can be described from
first principles, while others need to be based on appropriate models with
parameters tuned to data. In these lectures we provide an overview, discuss how
matrix elements are used, introduce the machinery for initial- and final-state
parton showers, explain how matrix elements and parton showers can be combined
for optimal accuracy, introduce the concept of multiple parton--parton
interactions, comment briefly on the hadronization issue, and provide an
outlook for the future.Comment: 23 pages, lectures presented at the 2006 European School of
High-Energy Physics, Aronsborg, Sweden, 18 June -- 1 July 200
Just a Taste: Lectures on Flavor Physics
We review the flavor structure of the Standard Model and the ways in which
the flavor parameters are measured. This is an extended writeup of the TASI
2016 lectures on flavor physics. Earlier versions of these lectures were
presented at pre-SUSY 2015 and Cornell University's Physics 7661 course in
2010.Comment: 138 pages, includes problems and solutions. To be published in the
proceedings of TASI 201
The TASTE Toolset: turning human designed heterogeneous systems into computer built homogeneous software.
The TASTE tool-set results from spin-off studies of the ASSERT project, which started in 2004 with the objective to propose innovative and pragmatic solutions to develop real-time software. One of the primary targets was satellite flight software, but it appeared quickly that their characteristics were shared among various embedded systems. The solutions that we developed now comprise a process and several tools ; the development process is based on the idea that real-time, embedded systems are heterogeneous by nature and that a unique UML-like language was not helping neither their construction, nor their validation. Rather than inventing yet another "ultimate" language, TASTE makes the link between existing and mature technologies such as Simulink, SDL, ASN.1, C, Ada, and generates complete, homogeneous software-based systems that one can straightforwardly download and execute on a physical target. Our current prototype is moving toward a marketed product, and sequel studies are already in place to support, among others, FPGA systems
On string integrability. A journey through the two-dimensional hidden symmetries in the AdS/CFT dualities
One of the main topics in the modern String Theory are the AdS/CFT dualities.
Proving such conjectures is extremely difficult since the gauge and string
theory perturbative regimes do not overlap. In this perspective, the discovery
of infinitely many conserved charges, i.e. the integrability, in the planar
AdS/CFT has allowed us to reach immense progresses in understanding and
confirming the duality. We review the fundamental concepts and properties of
integrability in two-dimensional sigma-models and in the AdS/CFT context. The
first part is focused on the AdS_5/CFT_4 duality, especially the classical and
quantum integrability of the type IIB superstring on AdS_5 x S^5 are discussed
in both pure spinor and Green-Schwarz formulations. The second part is
dedicated to the AdS_4/CFT_3 duality with particular attention to the type IIA
superstring on AdS_4 x CP^3 and its integrability. This review is based on a
shortened and revised version of the author's PhD thesis, discussed at Uppsala
University in September 2009.Comment: 116 pages, 11 figures, to be published in Advances in High Energy
Physics, Special Issue on ''Gauge/String Duality'
Energy transitions and uncertainty: creating low carbon investment opportunities in the UK electricity sector
This paper examines how actors in the UK electricity sector are attempting to deliver investment in low carbon generation. Low carbon technologies, because of their relative immaturity, capital intensity and low operational costs, do not readily fit with existing electricity markets and investment templates which were designed for fossil fuel based energy. We analyse key electricity market and infrastructure policies in the UK and highlight how these are aimed at making low carbon technologies ‘investable’ by reducing uncertainty, managing investment risks and repositioning actors within the electricity socio-technical ‘regime’. We argue that our study can inform contemporary debates on the politics and governance of sustainability transitions by empirically investigating the agency of incumbent regime actors in the face of uncertainty and by offering critical insights on the role of markets and finance in shaping socio-technical change
Current Developments and Problems of Electricity Regulation in the European Union and the United Kingdom
This paper deals current developments and the problems of regulation in European electricity in general and -in somewhat more detail-, England and Wales in particular.electricity
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