Guaranteed Non-quadratic Performance for Quantum Systems with Nonlinear   Uncertainties
  This paper presents a robust performance analysis result for a class of uncertain quantum systems containing sector bounded nonlinearities arising from perturbations to the system Hamiltonian. An LMI condition is given for calculating a guaranteed upper bound on a non-quadratic cost function. This result is illustrated with an example involving a Josephson junction in an electromagnetic cavity. 
Ian R. Petersen
quant-ph cs.SY math.OC