Simulations of ferrite-dielectric-wire composite negative index materials.

We perform extensive finite difference time domain simulations of ferrite based negative index of refraction composites. A wire grid is employed to provide negative permittivity. The ferrite and wire grid interact to provide both negative and positive index of refraction transmission peaks in the vicinity of the ferrite resonance.

Analysis of multiple time scales in a transistor amplifier.

It was shown previously in an experiment that when high frequency signals (on the order of 1 MHz) were injected into this low frequency amplifier, the nonlinearities of the pn junctions caused period doubling, chaos, and very low frequency oscillations (on the order of 1 Hz). In this paper we present theory and simulations to explain the existence of the low frequency oscillations.

Anomalous diffusion in infinite horizon billiards.

We consider the long time dependence for the moments of displacement <|r|(q)> of infinite horizon billiards, given a bounded initial distribution of particles. For a variety of billiard models we find <|r|(q)> approximately t(gamma(q)) (up to factors of ln t). The time exponent, gamma(q), is piecewise linear and equal to q/2 for q<2 and q-1 for q>2.

Long time algebraic relaxation in chaotic billiards.

The long-time algebraic relaxation process in spatially periodic billiards with infinite horizon is shown to display a self-similar time-asymptotic form. This form is identical for a class of such billiards, but can be different in an important special case.