k-String Tension from Eguchi-Kawai Reduction
  We consider three-dimensional SU(N) gauge theories with massless Dirac or Majorana fermions in the adjoint representation. We use the Eguchi-Kawai volume reduction to two-dimensions to calculate the tension sigma_k of the k-string in such theories. Under some assumptions whose validity we discuss, we derive the previously conjectured sine formula, sigma_k ~ N sin pi k/N. 
Adi Armoni, Daniele Dorigoni, Gabriele Veneziano
hep-th hep-lat