Generation of non-Gaussian states in a cyclic four-wave-mixing system with photon-number projections
Boxuan Jing, Feng-Xiao Sun, X. D. Yu, Qiongyi He · Physical Review A · 2025
Continuous-variable entanglement, especially in the non-Gaussian states exhibiting Wigner negativity, is essential for realizing quantum advantages in quantum information processing tasks. Here, we propose a method to efficiently generate multimode non-Gaussian entangled states using a single Rb vapor cell integrated with a cyclic optical system. By employing multiple pump light pulses and recycling the output signal light as a seed light, our system is equivalent to implementing the multiple cascaded four-wave mixing processes while maintaining resource efficiency. Through the analysis of the properties of multipartite steering and entanglement in the cyclic system, we find a hierarchical Gaussian steering structure, which enables the photon number projection on superior signal mode to prepare a multimode entangled non-Gaussian state in the idler modes. Conversely, the projection on each subordinate idler mode can induce more negativity in the signal mode. More importantly, our approach significantly improves the success probability of photon number projections, thereby augmenting the yield of non-Gaussian states and enhancing their potential for delivering robust quantum advantages.