Photonic quantum information processing, one of the leading platforms for quantum technologies^1,2,3,4,5, critically relies on optical quantum interference to produce an indispensable effective photon–photon interaction. However, such an effective interaction is fundamentally limited to bunching⁶ due to the bosonic nature of photons⁷ and the restricted phase response from conventional unitary optical elements^8,9. Here we propose and experimentally demonstrate a new degree of freedom in the optical quantum interference enabled by a non-unitary metasurface. Due to the unique anisotropic phase response that creates two extreme eigen-operations, we show dynamical and continuous control over the effective interaction of two single photons such that they show bosonic bunching, fermionic antibunching or arbitrarily intermediate behaviour, beyond their intrinsic bosonic nature. This quantum operation opens the door to both fundamental quantum light–matter interaction and innovative photonic quantum devices for quantum communication, quantum simulation and quantum computing.

光子量子信息处理是量子技术^1,2,3,4,5的主要平台之一，它严重依赖光学量子干涉来产生不可或缺的有效光子-光子相互作用。然而，由于光子⁷的玻色子性质和传统单一光学元件^8,9的受限相位响应，这种有效的相互作用从根本上仅限于聚束⁶. 在这里，我们提出并通过实验证明了由非单一超表面实现的光学量子干涉的新自由度。由于独特的各向异性相位响应产生了两个极端的本征操作，我们展示了对两个单光子有效相互作用的动态和连续控制，使得它们表现出玻色子聚束、费米子反聚束或任意中间行为，超出了它们固有的玻色子性质。这种量子操作为基础量子光-物质相互作用和用于量子通信、量子模拟和量子计算的创新光子量子器件打开了大门。