20,685 research outputs found
Dynamic Renormalization Group Approach to Self-Organized Critical Phenomena
Two different models exhibiting self-organized criticality are analyzed by
means of the dynamic renormalization group. Although the two models differ by
their behavior under a parity transformation of the order parameter, it is
shown that they both belong to the same universality class, in agreement with
computer simulations. The asymptotic values of the critical exponents are
estimated up to one loop order from a systematic expansion of a nonlinear
equation in the number of coupling constants.Comment: 8 pages, RevTeX 3.0, 1 PostScript figure available upon reques
Slow light in molecular aggregates nanofilms
We study slow light performance of molecular aggregates arranged in nanofilms
by means of coherent population oscillations (CPO). The molecular cooperative
behavior inside the aggregate enhances the delay of input signals in the GHz
range in comparison with other CPO-based devices. Moreover, the problem of
residual absorption present in CPO processes, is removed. We also propose an
optical switch between different delays by exploiting the optical bistability
of these aggregates.Comment: 4 pages, 4 figure
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