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 investigate some properties of the standard rotator approximation of theSU$(N)\times\,$SU$(N)$ sigma-model in the delta-regime. In particular we showthat the isospin susceptibility calculated in this framework agrees with thatcomputed by chiral perturbation theory up to next-to-next to leading order inthe limit $\ell=L_t/L\to\infty\,.$ The difference between the results involvesterms vanishing like $1/\ell\,,$ plus terms vanishing exponentially with$\ell\,$. As we have previously shown for the O($n$) model, this deviation canbe described by a correction to the rotator spectrum proportional to the squareof the quadratic Casimir invariant. Here we confront this expectation withanalytic nonperturbative results on the spectrum in 2 dimensions for $N=3\,.$

On the rotator Hamiltonian for the SU$(N)\times\,$SU$(N)$ sigma-model in the delta-regime