Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, D-85748 Garching, Germany.
Physik-Department, Technische Universität München, D-85748 Garching, Germany.
Phys Rev Lett. 2016 Jul 8;117(2):020502. doi: 10.1103/PhysRevLett.117.020502. Epub 2016 Jul 7.
Displacement of propagating quantum states of light is a fundamental operation for quantum communication. It enables fundamental studies on macroscopic quantum coherence and plays an important role in quantum teleportation protocols with continuous variables. In our experiments, we have successfully implemented this operation for propagating squeezed microwave states. We demonstrate that, even for strong displacement amplitudes, there is no degradation of the squeezing level in the reconstructed quantum states. Furthermore, we confirm that path entanglement generated by using displaced squeezed states remains constant over a wide range of the displacement power.
光传播量子态的位移是量子通信的基本操作。它能够实现对宏观量子相干的基础研究,并在连续变量的量子隐形传态协议中发挥重要作用。在我们的实验中,我们成功地对传播压缩微波态执行了这一操作。我们证明,即使在强位移幅度的情况下,在重建量子态中也不会降低压缩水平。此外,我们证实,通过使用位移压缩态产生的路径纠缠在很大的位移功率范围内保持不变。