Strong global correlations in the systems of coupled chaotic map lattices based on a modified logistic map are investigated. It is shown that, in the parameter range close to the edge of chaos as defined for an individual map, the systems exhibit off-diagonal long-range order and single-particle reduced density matrices defined in a natural way possess one strongly dominant eigenvalue. In addition, pattern formation [13] in the above systems has been investigated.
We investigate numerically the problem of optimization of directional characteristics of dipole antennas located inside, or in the vicinity of, photonic crystals or more general artificial dielectrics, made of very thin perfectly conducting wires. We concentrate on two-dimensional propagation. Simulated annealing is used to find the distribution of wires which optimizes the directional pattern. It is demonstrated that high directivity can be obtained for systems containing a very small number of elements provided that the size and shape of the unit cell as well as the position of the radiating source with respect to the crystal are optimized. Building up of the radiation pattern is also illustrated with the help of the wave-optical rays.
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