Finite size spectrum of SU(N) principal chiral field from discrete Hirota dynamics

摘要: Using recently proposed method of discrete Hirota dynamics for integrable (1 + 1)D quantum field theories on a finite space circle length L we derive and test numerically system nonlinear integral equations the exact spectrum energies SU(N) x principal chiral model as functions mL, where m is mass scale. We propose determinant solution underlying Y-system, or equation, in terms Wronskian determinants N matrices parameterized by - 1 spectral parameter theta with known analytic properties at L. Although works principle any state, explicit are written states U(1) sector only. For > 2, encounter clarify few subtleties these related to presence bound states, absent previously considered = 2 case. As demonstration efficiency our method, solve low-lying 3 wide range mL. (C) 2015 The Authors. Published Elsevier B.V.