6,282 research outputs found
Nonequilibrium mesoscopic transport: a genealogy
Models of nonequilibrium quantum transport underpin all modern electronic
devices, from the largest scales to the smallest. Past simplifications such as
coarse graining and bulk self-averaging served well to understand electronic
materials. Such particular notions become inapplicable at mesoscopic
dimensions, edging towards the truly quantum regime. Nevertheless a unifying
thread continues to run through transport physics, animating the design of
small-scale electronic technology: microscopic conservation and nonequilibrium
dissipation. These fundamentals are inherent in quantum transport and gain even
greater and more explicit experimental meaning in the passage to atomic-sized
devices. We review their genesis, their theoretical context, and their
governing role in the electronic response of meso- and nanoscopic systems.Comment: 21p
Fully differential NNLO computations with MATRIX
We present the computational framework MATRIX which allows us to evaluate
fully differential cross sections for a wide class of processes at hadron
colliders in next-to-next-to-leading order (NNLO) QCD. The processes we
consider are and hadronic reactions involving Higgs and
vector bosons in the final state. All possible leptonic decay channels of the
vector bosons are included for the first time in the calculations, by
consistently accounting for all resonant and non-resonant diagrams, off-shell
effects and spin correlations. We briefly introduce the theoretical framework
MATRIX is based on, discuss its relevant features and provide a detailed
description of how to use MATRIX to obtain NNLO accurate results for the
various processes. We report reference predictions for inclusive and fiducial
cross sections of all the physics processes considered here and discuss their
corresponding uncertainties. MATRIX features an automatic extrapolation
procedure that allows us, for the first time, to control the systematic
uncertainties inherent to the applied NNLO subtraction procedure down to the
few permille level (or better).Comment: 76 pages, 2 figures, 11 table
Jorge A. Swieca's contributions to quantum field theory in the 60s and 70s and their relevance in present research
After revisiting some high points of particle physics and QFT of the two
decades from 1960 to 1980, I comment on the work by Jorge Andre Swieca. I
explain how it fits into the quantum field theory during these two decades and
draw attention to its relevance to the ongoing particle physics research. A
particular aim of this article is to direct thr readers mindfulness to the
relevance of what at the time of Swieca was called "the Schwinger Higgs
screening mechanism". which, together with recent ideas which generalize the
concept of gauge theories, has all the ingredients to revolutionize the issue
of gauge theories and the standard model.Comment: 49 pages, expansion and actualization of text, improvement of
formulations and addition of many references to be published in EPJH -
Historical Perspectives on Contemporary Physic
Measuring Multijet Structure of Hadronic Energy Flow Or What IS A Jet?
Ambiguities of jet algorithms are reinterpreted as instability wrt small
variations of input. Optimal stability occurs for observables possessing
property of calorimetric continuity (C-continuity) predetermined by kinematical
structure of calorimetric detectors. The so-called C-correlators form a basic
class of such observables and fit naturally into QFT framework, allowing
systematic theoretical studies. A few rules generate other C-continuous
observables. The resulting C-algebra correctly quantifies any feature of
multijet structure such as the "number of jets" and mass spectra of "multijet
substates". The new observables are physically equivalent to traditional ones
but can be computed from final states bypassing jet algorithms which reemerge
as a tool of approximate computation of C-observables from data with all
ambiguities under analytical control and an optimal recombination criterion
minimizing approximation errors.Comment: PostScript, 94 pp (US Letter), 18 PS files, [email protected]
Computing with space: a tangle formalism for chora and difference
What is space computing,simulation, or understanding? Converging from several sources, this seems to be something more primitive than what is meant nowadays by computation, something that was along with us since antiquity (the word "choros", "chora", denotes "space" or "place" and is seemingly the most mysterious notion from Plato, described in Timaeus 48e - 53c) which has to do with cybernetics and with the understanding of the front end visual system. It may have some unexpected applications, also. \ud
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Here, inspired by Bateson (see Supplementary Material), I explore from the mathematical side the point of view that there is no difference between the map and the territory, but instead the transformation of one into another can be understood by using a formalism of tangle diagrams
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