Research On Multi-hop Teleportation Method In High-dimensional Uantum Network

In recent decades,quantum communication theory has gradually become a very important research direction for its remarkable advantage in information security and communication capacity.The early quantum communication schemes were mainly proposed for point-to-point information transmission.With the rapid development of quantum communication technology,its application fields keep expanding,the networked communication systems are required to establish to meet the complex communication reality.However,due to the limitation of inevitable coupling effects and physical operation technology etc.,it is difficult to directly distribute the maximally entangled resources between two communication terminals,and it is impossible to perform the complicated unitary operations of quantum communication process.Therefore,the construction of high-speed and long-distance quantum communication network still faces huge challengesTo address the problems of non-maximally entangled evolution of maximally entangled channels and the unitary operation of multi-qudits,in this paper,we investigate the quantum teleportation network in high-dimensional Hilbert space and put forward three multi-hop teleportation methods.First,in order to teleport an unknown qudit state between two remote communication terminals which don't share the direct entangled channel,we propose a high-dimensional multi-hop nondestructive teleportation protocol based on non-maximally entangled Bell chain.The traditional probabilistic teleportation has a certain probability of failure in the transmission of original state,and the unknown state to be teleported would be lost when the teleportation fails.We explore the nondestructive probabilistic teleportation which could restore the original state even the teleportation fails In this way,the original unknown state could be re-teleported via other available quantum entangled channels.Secondly,we propose a nondestructive multi-hop teleportation method between terminal nodes equipped with limited technology.In above mentioned scheme,the main unitary operations are required to perform by the communication terminals.However,the limited quantum operation technology makes it unrealistic to equip multiple nodes with complicated high-dimensional quantum operation capability.Thereby,the above multi-hop teleportation network architecture could be adjusted.We consider that there are certain cloud nodes in a quantum network which are equipped with high-dimensional quantum processing capability of performing required multi-qudit unitary operations,while the ordinary intermediate nodes and the terminals are provided with limited technical capabilities such as single-particle measurement and Bell state measurement etc.to cooperatively assist the teleportation.Finally,we give a high-dimensional chain teleportation method based on optional processing terminals.All intermediate nodes simultaneously perform Bell measurement and transmit the measurement results to the processor node.After gathering all Bell measurement results,the processor node reasonably allocates the unitary operation tasks to two terminals on account of the processing capability and efficiency for modulating the directly entangled channel,which greatly reduces the workload of single terminal operation.