NLIE METHOD FOR THE SPECTRAL PROBLEM OF AdS5 × S5

Abstract

The excited state spectrum of AdS5 × S5 string can be computed exactly by the mirror TBA equations. We discuss an equivalent, smaller set of equations called hybrid nonlinear integral equations (NLIE). The hybrid NLIE is written by new dynamical degrees of freedom, analogous to spinon variables in condensed matter systems. This derivation is applicable to any integrable systems which obey A1 T-system equipped with certain analyticity conditions. A case study of orbifold Konishi state shows that the new method relieves the problem of criticality in the mirror TBA equations.