Implementing arbitrary multimode continuous-variable quantum gates with fixed non-Gaussian states and adaptive linear optics
Fumiya Hanamura, Warit Asavanant, H. Nagayoshi, A. Sakaguchi, Ryuhoh Ide, Kosuke Fukui, Peter van Loock, Akira Furusawa · Physical Review A · 2024
Non-Gaussian quantum gates are essential components for optical quantum information processing. However, the efficient implementation of practically important multimode higher-order non-Gaussian gates has not been comprehensively studied. We propose a measurement-based method to directly implement general, multimode, and higher-order non-Gaussian gates using only fixed non-Gaussian ancillary states and adaptive linear optics. Compared to existing methods, our method allows for a more resource-efficient and experimentally feasible implementation of multimode gates that are important for various applications in optical quantum technology, such as the two-mode cubic quantum nondemolition gate or the three-mode continuous-variable Toffoli gate, and their higher-order extensions. Our results will expedite the progress toward fault-tolerant universal quantum computing with light. Published by the American Physical Society 2024