Ewert Fabian, van Loock Peter
Institute of Physics, Johannes-Gutenberg Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
Phys Rev Lett. 2014 Oct 3;113(14):140403. doi: 10.1103/PhysRevLett.113.140403. Epub 2014 Sep 30.
It is well known that an unambiguous discrimination of the four optically encoded Bell states is possible with a probability of 50% at best, when using static, passive linear optics and arbitrarily many vacuum-mode ancillae. By adding unentangled single-photon ancillae, we are able to surpass this limit and reach a success probability of at least 75%. We discuss the error robustness of the proposed scheme and a generalization to reach a success probability arbitrarily close to 100%.
众所周知，当使用静态、无源线性光学器件和任意多个真空模式辅助量子比特时，对四个光学编码的贝尔态进行明确区分的概率最高只能达到50%。通过添加非纠缠单光子辅助量子比特，我们能够突破这一限制，使成功概率至少达到75%。我们讨论了所提出方案的误差鲁棒性以及一种推广方法，以实现成功概率任意接近100%。
