量子直接传态

Quantum direct portation

把一个任意量子态在既有噪声又有窃听的信道下安全可靠地传输,是一个广泛而重要的问题.现在已有的方法是先传输大量的Einstein-Podolsky-Rosen (EPR)纠缠对,然后进行纠缠纯化,获得一对近似完美的纠缠对,再进行隐形传态或者远程态制备来传输量子态.本文给出一种直接安全传输量子态的方法,通过使用量子直接通信,安全地传输大量同样的任意量子态,然后利用单量子态的纯化方法,得到一个近于完美的量子态.这是一种不需要量子纠缠的量子态安全传输方法,避免使用纠缠资源.这种方案是量子隐形传态和远程态制备之外的又一途径.此外,这一方案将原来只是用来传输经典信息的量子安全直接通信扩展到传输任意量子态的新领域,扩大了量子直接通信的用途.这一方案将在未来量子互联网中有重要的应用.

Quantum state that carries classical information,0 or 1,can be safely and reliably transmitted using quantum secure direct communication.How to transmit an arbitrary quantum state is a wider issue and has important applications.One way is to use quantum teleportation,namely,first distribute a large number of Einstein-Podolsky-Rosen pairs,and then perform entanglement purification to obtain a near-perfect pair,and make quantum teleportation using the pair.In this article,we propose a method that directly port the quantum state with security and reliability using quantum secure direct communication.After sufficient number of copies of the same state have been directly ported,single-particle purification is performed to obtain a near perfect single particle state.This is important because it offers a new method for sending an arbitrary single particle state securely and reliably without using quantum teleportation.It is also an important extension of quantum secure direct communication to send an arbitrary quantum state.Quantum direct portation will have great potential in quantum internet.