Monika Monika, Nosrati Farzam, George Agnes, Sciara Stefania, Fazili Riza, Marques Muniz André Luiz, Bisianov Arstan, Lo Franco Rosario, Munro William J, Chemnitz Mario, Peschel Ulf, Morandotti Roberto
Institute of Condensed Matter Theory and Optics, Friedrich-Schiller-University, Jena, Germany.
Institut national de la recherche scientifique, Centre Énergie Matériaux Télécommunications, Varennes, Quebec Canada.
Nat Photonics. 2025;19(1):95-100. doi: 10.1038/s41566-024-01546-4. Epub 2024 Oct 14.
Quantum walks on photonic platforms represent a physics-rich framework for quantum measurements, simulations and universal computing. Dynamic reconfigurability of photonic circuitry is key to controlling the walk and retrieving its full operation potential. Universal quantum processing schemes based on time-bin encoding in gated fibre loops have been proposed but not demonstrated yet, mainly due to gate inefficiencies. Here we present a scalable quantum processor based on the discrete-time quantum walk of time-bin-entangled photon pairs on synthetic temporal photonic lattices implemented on a coupled fibre-loop system. We utilize this scheme to path-optimize quantum state operations, including the generation of two- and four-level time-bin entanglement and the respective two-photon interference. The design of the programmable temporal photonic lattice enabled us to control the dynamic of the walk, leading to an increase in the coincidence counts and quantum interference measurements without recurring to post-selection. Our results show how temporal synthetic dimensions can pave the way towards efficient quantum information processing, including quantum phase estimation, Boson sampling and the realization of topological phases of matter for high-dimensional quantum systems in a cost-effective, scalable and robust fibre-based setup.
光子平台上的量子行走代表了一个用于量子测量、模拟和通用计算的富含物理内容的框架。光子电路的动态可重构性是控制行走并挖掘其全部操作潜力的关键。基于门控光纤环中的时间槽编码的通用量子处理方案已被提出，但尚未得到验证，主要原因是门效率低下。在此，我们展示了一种基于离散时间量子行走的可扩展量子处理器，该行走由在耦合光纤环系统上实现的合成时间光子晶格上的时间槽纠缠光子对完成。我们利用该方案对量子态操作进行路径优化，包括生成两能级和四能级时间槽纠缠以及相应的双光子干涉。可编程时间光子晶格的设计使我们能够控制行走的动态过程，从而在不进行后选择的情况下增加符合计数和量子干涉测量。我们的结果表明，时间合成维度如何能够为高效量子信息处理铺平道路，包括量子相位估计、玻色子采样以及在具有成本效益、可扩展且稳健的基于光纤的装置中实现高维量子系统的物质拓扑相。
