1983/01/01 by T. Koide, A. H. Treiman, M. J. Drake · 4 citations
Computer Science · Engineering · Mathematics · Physics and Astronomy · #Advanced Mathematical Modeling in Engineering #Astro and Planetary Science #Fractional Differential Equations Solutions #Planetary Science and Exploration #Space Exploration and Technology #Theoretical and Computational Physics #cond-mat.stat-mech #hep-ph #nucl-th
paper · pdf · doi:10.1103/physreve.72.026135
published as Phys.Rev. E72 (2005) 026135 · 10 pages, 1 figure, Final version published in Phys. Rev. E
openalex publication_date 1983/01/01 · arxiv created 2005/08/22 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/06/11
We derive a coarse-grained equation of motion of a number density by applying the projection operator method to a non-relativistic model. The derived equation is an integrodifferential equation and contains the memory effect. The equation is consistent with causality and the sum rule associated with the number conservation in the low momentum limit, in contrast to usual acausal diffusion equations given by using the Fick's law. After employing the Markov approximation, we find that the equation has the similar form to the causal diffusion equation. Our result suggests that current-current correlations are not necessarily adequate as the definition of diffusion constants.