提出一个基于第三方控制的量子双向传态方案:通信双方Alice、Bob和控制方Charlie事先共享 一个六粒子团簇态,通信开始后, Alice、Bob分别对自己拥有的部分粒子作Bell基联合测量(BSM), 若控制方同意双方通信,则对自己拥有的粒子对作测量,将粒子所处的态公布;通信双方根据控制方公 布的测量结果,对各自的某些粒子作适当的幺正变换,即可在这些粒子上重建对方要传的态。由于加入了 第三方的控制,双向传态的安全性得到了提高。

A scheme of two-way quantum teleportation controlled by a third party was proposed. Two sides of communication (Alice and Bob) and the controller Charlie shared a six-qubit cluster state in advance. Firstly, Alice and Bob performed Bell-state measurements(BSMs) on parts of their qubit pairs, respectively. If Charlie agreed them to communication, he should measure his qubits and announce their states. According to Charlie’s measured results, the two sides of communication performed some appropriately unitary transformations on their qubits respectively. Then they were able to reconstruct each other’s unknown state on their own qubits. The security of two-way communication was improved because of the control of the third party.