English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Using an analogy between the conductivity tensor of electronic systems andthe spin stiffness tensor of spin systems, we introduce the concept of theThouless number $g_0$ and the dimensionless frequency dependent conductance $g(\omega )$ for quantum spin models. It is shown that spin diffusion implies thevanishing of the Drude peak of $g ( \omega )$, and that the spin diffusioncoefficient $D_s$ is proportional to $g_0$. We develop a new method based onthe Thouless number to calculate $D_s$, and present results for $D_s$ in thenearest-neighbor quantum Heisenberg ferromagnet at infinite temperatures forarbitrary dimension $d$ and spin $S$.Comment: 13 pages, written in latex MPLA2.sty (latex style distributed by  International Journal of Modern Physics, the style file is given at the  beginning, so just run latex

THOULESS NUMBER AND SPIN DIFFUSION IN QUANTUM HEISENBERG FERROMAGNETS