Density dynamics from current auto-correlations at finite time- and length-scales
Autor(en): | Steinigeweg, R. Wichterich, H. Gemmer, J. |
Stichwörter: | FOURIERS LAW; HEAT-CONDUCTION; IRREVERSIBLE-PROCESSES; MODEL; Physics; Physics, Multidisciplinary; STATISTICAL-MECHANICAL THEORY; TRANSPORT-COEFFICIENTS | Erscheinungsdatum: | 2009 | Herausgeber: | IOP PUBLISHING LTD | Journal: | EPL | Volumen: | 88 | Ausgabe: | 1 | Zusammenfassung: | We consider the increase of the spatial variance of some inhomogeneous, non-equilibrium density (particles, energy, etc.) in a periodic quantum system of condensed-matter type. This is done for a certain class of initial quantum states which is supported by static linear response and typicality arguments. We directly relate the broadening to some current auto-correlation function at finite times. Our result is not limited to diffusive behavior, however, in that case it yields a generalized Einstein relation. These findings facilitate the approximation of diffusion constants/conductivities on the basis of current auto-correlation functions at finite times for finite systems. Pursuing this, we quantitatively confirm the magnetization diffusion constant in a spin chain which was recently found from non-equilibrium bath scenarios. Copyright (C) EPLA, 2009 |
ISSN: | 02955075 | DOI: | 10.1209/0295-5075/88/10004 |
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