Direct quantum error detection in spatially multiplexed transmission

The detection and correction of quantum errors is of particular importance to high performance and scalability of quantum systems [1]. Whereas photonic technologies promise long-distance transfer of quantum information, photons in their propagation channels (e.g. fibers or free-space) particularly suffer from arbitrary phase fluctuations spanning the whole 2p range [2]. However the established protocols for solid state quantum particles commonly assume p-phase flip errors [1], and a possibility to directly detect arbitrary continuous phase errors remained an open question.