Augmenting a train of bright phase-modulated laser-light pulses of a coherent communications system with infinitesimally small quantum photons per pulse -- entangled across several time bins -- prepared by splitting squeezed light in a temporal-mode interferometer can dramatically enhance a homodyne receiver's ability to detect a sudden change in the channel loss, by up to a factor that is the inverse of the pre-change loss, without affecting the communications rate. We discuss the quantum limit of quickest change detection, and the problem of joint communications and change detection that our study opens up.

翻译：在相干通信系统中，通过将一列明亮的相位调制激光脉冲与每脉冲无限小的量子光子（这些光子在多个时间仓之间纠缠）相结合，这些光子由压缩光在时模干涉仪中分束制备，可以显著增强零差接收机检测信道损耗突然变化的能力，提升因子最高可达变化前损耗的倒数，同时不影响通信速率。我们讨论了最快变化检测的量子极限，以及本研究提出的联合通信与变化检测问题。