245 research outputs found
A coupled bispectral, temporal and spatial coherence function of the pressure field, scattered from a moving sea surface (A)
Simulated performance of an acoustic modem using phase-modulated signals in a time-varying, shallow-water environment
Influence of statistical surface models on dynamic scattering of high-frequency signals from the ocean surface (A)
Scattering Equations and Feynman Diagrams
We show a direct matching between individual Feynman diagrams and integration
measures in the scattering equation formalism of Cachazo, He and Yuan. The
connection is most easily explained in terms of triangular graphs associated
with planar Feynman diagrams in -theory. We also discuss the
generalization to general scalar field theories with interactions,
corresponding to polygonal graphs involving vertices of order . Finally, we
describe how the same graph-theoretic language can be used to provide the
precise link between individual Feynman diagrams and string theory integrands.Comment: 18 pages, 57 figure
Report on completed/demonstrated rearing system - Farmergødning/Bånlev
Rapport omhandlende kompostering af gødning med fluelarver på prototype
Larvae for layers
Companies and researchers are in close collaboration developing a container- based system for cultivating fly larvae at organic poultry farms. In a one week process, manure will be converted to compost and the live larvae will be harvested and used for feeding laying hens. The larvae are expected to have a beneficial effect on the growth performance, intestinal health and on animal behavior in flocks
Integration Rules for Loop Scattering Equations
We formulate new integration rules for one-loop scattering equations
analogous to those at tree-level, and test them in a number of non-trivial
cases for amplitudes in scalar -theory. This formalism greatly
facilitates the evaluation of amplitudes in the CHY representation at one-loop
order, without the need to explicitly sum over the solutions to the loop-level
scattering equations.Comment: 22 pages, 17 figure
Integration Rules for Scattering Equations
As described by Cachazo, He and Yuan, scattering amplitudes in many quantum
field theories can be represented as integrals that are fully localized on
solutions to the so-called scattering equations. Because the number of
solutions to the scattering equations grows quite rapidly, the contour of
integration involves contributions from many isolated components. In this
paper, we provide a simple, combinatorial rule that immediately provides the
result of integration against the scattering equation constraints for any
M\"obius-invariant integrand involving only simple poles. These rules have a
simple diagrammatic interpretation that makes the evaluation of any such
integrand immediate. Finally, we explain how these rules are related to the
computation of amplitudes in the field theory limit of string theory.Comment: 30 pages, 29 figure
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