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

We consider the XXZ quantum spin chain in its massless, disordered regime atzero field. We derive an exact expression for the two-spinon form-factor of$S^z=1/2\sigma^z$ by taking a limit of the massive XYZ form-factors found byLashkevich and by Lukyanov and Terras. This result is used to find thetwo-spinon contribution to the spectral decomposition of the longitudinalstructure factor $S^{zz}(k,w)$. We find that this contribution provides anaccurate approximation to the full structure factor over a wide range of theanisotropy parameter. The asymptotic behaviour of $S^{zz}(k,w)$ is computed asthe upper and lower $w$ thresholds of the two-spinon $(w,k)$ band areapproached, and an analysis of the region of validity of this thresholdbehaviour is performed. Our results reproduce and refine existing thresholdbehaviour predictions and extend these results to an accurate descriptionthroughout the two-spinon continuum.

Exact Form-Factor Results for the Longitudinal Structure Factor of the Massless XXZ Model in Zero Field