Dynamical switchable quantum nonreciprocity induced by off-resonant chiral two-photon driving

Optical nonreciprocity, which refers to the direction-dependent emission, scattering and absorption of photons, plays a very important role in quantum engineering and quantum information processing. Here, we propose an all-optical approach to achieve the optical dynamical switchable quantum nonreciprocity by an off-resonant chiral two-photon driving in a single microring cavity, which differs from the conventional nonreciprocal schemes. It is shown that the optical field with time-dependent statistical properties can be generated and the nonreciprocity flips periodically, with switchable photon blockade and photon-induced tunneling effects. We find that the dynamical system is robust and immune to the parameter variations, which loosens the parameter range of system. Meanwhile, the time window for one-way quantum information is sufficiently wide and tunable. Our work opens a new idea for the current quantum nonreciprocal research, which can facilitate a memory functionality and be used for future in-memory superconducting quantum compute. The other nonreciprocal quantum devices, i.e., dynamical switchable nonreciprocal squeezing and entanglement, may be inspired by our method, which is expected to have important applications in future quantum technology.