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| Journal Article | PreJuSER-12812 |
; ;
2000
APS
College Park, Md.
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Please use a persistent id in citations: http://hdl.handle.net/2128/9308 doi:10.1103/PhysRevE.62.6071
Abstract: The dynamics of a coupled two-component nonequilibrium system is examined by means of continuum field theory representing the corresponding master equation. Particles of species A may perform hopping processes only when particles of different type B are present in their environment. Species B is subject to diffusion-limited reactions. If the density of B particles attains a finite asymptotic value (active state), the A species displays normal diffusion. On the other hand, if the B density decays algebraically proportional tot(-alpha) at long times (inactive state), the effective attractive A-B interaction is weakened. The combination of B decay and activated A hopping processes gives rise to anomalous diffusion, with mean-square displacement ((x) over right arrow (A)(t)(2)) proportional to t(1-alpha) for alpha <1. Such algebraic subdiffusive behavior ensues for nth-order B annihilation reactions (nB-->O) with n greater than or equal to 3, and n = 2 for d<2. The mean-square displacement of the A particles grows only logarithmically with time in the case of B pair annihilation (n = 2) and d<greater than or equal to>2 dimensions. For radioactive B decay (n = 1), the A particles remain localized. If the A particles may hop spontaneously as well, or if additional random forces are present, the A-B couplings becomes irrelevant, and conventional diffusion is recovered in the long-time limit.
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