Improving the capacity of quantum dense coding via non-Hermitian operation

Abstract

Abstract We propose a novel method to enhance the capacity of quantum dense coding under amplitude damping noise using non-Hermitian operations. With the assistance of non-Hermitian operations, we show that the capacity of quantum dense coding can always be larger than 1 for any two-qubit states. In particular, the non-Hermitian operation can improve quantum dense coding more efficiently in the case of strong decoherence strength than those with small decoherence strength. Our results shed new light on the protection of quantum dense coding in a quantum environment.