2016/01/18 by Valentina Forini, Lorenzo Bianchi, Marco S. Bianchi +2 · 2 citations
Physics and Astronomy · #hep-lat #hep-th
published as PoS(LATTICE 2015)244 · Contribution to the proceedings of Lattice 2015, July 14--18, Kobe, Japan
arxiv created 2016/01/18 · arxiv updated 2016/01/19
We consider a possible discretization for the gauge-fixed Green-Schwarz (two-dimensional) sigma-model action for the Type IIB superstring and use it for measuring the cusp anomalous dimension of planar N=4 SYM as derived from string theory. We perform lattice simulations employing a Rational Hybrid Monte Carlo (RHMC) algorithm and a Wilson-like fermion discretization. In this preliminary study, we compare our results with the expected behavior for very large values of g=(√λ)/(4π), which is the perturbative regime of the sigma-model, and find a qualitative agreement at finite lattice spacing. For smaller g the continuum limit is obstructed by a divergence. We also detect a phase in the fermion determinant, whose origin we explain, which for small g leads to a sign problem not treatable via standard reweigthing. Results presented here are discussed thoroughly in~\citetoappear.