Edge exponent in the dynamic spin structure factor of the Yang-Gaudin model

Abstract

The dynamic spin structure factor $\mathcal{S}(k,ω)$ of a system of spin-1/2 bosons is investigated at arbitrary strength of interparticle repulsion. As a function of $ω$ it is shown to exhibit a power-law singularity at the threshold frequency defined by the energy of a magnon at given $k.$ The power-law exponent is found exactly using a combination of the Bethe Ansatz solution and an effective field theory approach.

4 pages, 2 figures