Quantum channel capacity by simulated annealing

Abstract

It is shown how simulated annealing can be used to determine the accessible information and the capacity of a quantum channel. The method is applied to a specific example of a symmetric N-state quantum channel that frequently appears in the analysis of eavesdropping in quantum key distribution protocols. The numerical results for the accessible information of this quantum channel are compared with recently published analytical solutions showing excellent agreement. Furthermore, interesting results concerning the capacity of a symmetric quantum channel are presented. © 2005 The American Physical Society.