5,146 research outputs found
Leading Infrared Logarithms from Unitarity, Analyticity and Crossing
We derive non-linear recursion equations for the leading infrared logarithms
in massless non-renormalizable effective field theories. The derivation is
based solely on the requirements of the unitarity, analyticity and crossing
symmetry of the amplitudes. That emphasizes the general nature of the
corresponding equations. The derived equations allow one to compute leading
infrared logarithms to essentially unlimited loop order without performing a
loop calculation. For the implementation of the recursion equation one needs to
calculate tree diagrams only. The application of the equation is demonstrated
on several examples of effective field theories in four and higher space-time
dimensions.Comment: 12 page
A Quality and Cost Approach for Comparison of Small-World Networks
We propose an approach based on analysis of cost-quality tradeoffs for
comparison of efficiency of various algorithms for small-world network
construction. A number of both known in the literature and original algorithms
for complex small-world networks construction are shortly reviewed and
compared. The networks constructed on the basis of these algorithms have basic
structure of 1D regular lattice with additional shortcuts providing the
small-world properties. It is shown that networks proposed in this work have
the best cost-quality ratio in the considered class.Comment: 27 pages, 16 figures, 1 tabl
Action functionals for strings in four dimensions
All possible action functionals on the space of surfaces in that
depend only on first and second derivatives of the functions, entering the
equation of the surface, and satisfy the condition of invariance with respect
to rigid motions are described.Comment: 9 pages, LaTeX, 7 figure
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