Nonreciprocal unconventional photon blockade with spinning atom-cavity

In this work, we propose to manipulate the statistical properties of the photons transport nonreciprocally via rotating nonlinear devices consisting of an atom coupled to a spinning cavity. This nonreciprocal effect allows the flow of light from one side but blocks it from the other with the same driving strength. We show that the nonreciprocal unconventional photon blockade can happen when the cavity is driven by the laser field. Under the weak driving condition, we discuss the physical origins of the nonreciprocal unconventional photon blockade, which originates from the destructive quantum interference between different paths from the ground state to the two-photon state by driving the device from the left side, while the quantum interference paths are broken when the device is driven from the right side, which leads to the occurring of the photon bunching. The optimal conditions for strong photon antibunching are analytically derived, which are in good agreement with those obtained by numerical simulations. Our proposal has potential applications for the on-chip nonreciprocal single-photon devices and provides an effective way for potential applications in solid state quantum computation and quantum information process.