Kannan B, Campbell D L, Vasconcelos F, Winik R, Kim D K, Kjaergaard M, Krantz P, Melville A, Niedzielski B M, Yoder J L, Orlando T P, Gustavsson S, Oliver W D
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Sci Adv. 2020 Oct 7;6(41). doi: 10.1126/sciadv.abb8780. Print 2020 Oct.
Realizing a fully connected network of quantum processors requires the ability to distribute quantum entanglement. For distant processing nodes, this can be achieved by generating, routing, and capturing spatially entangled itinerant photons. In this work, we demonstrate the deterministic generation of such photons using superconducting transmon qubits that are directly coupled to a waveguide. In particular, we generate two-photon N00N states and show that the state and spatial entanglement of the emitted photons are tunable via the qubit frequencies. Using quadrature amplitude detection, we reconstruct the moments and correlations of the photonic modes and demonstrate state preparation fidelities of 84%. Our results provide a path toward realizing quantum communication and teleportation protocols using itinerant photons generated by quantum interference within a waveguide quantum electrodynamics architecture.
实现量子处理器的全连接网络需要具备分发量子纠缠的能力。对于相距遥远的处理节点，这可以通过生成、路由和捕获空间纠缠的巡游光子来实现。在这项工作中，我们展示了使用直接耦合到波导的超导transmon量子比特来确定性地生成此类光子。特别是，我们生成了双光子N00N态，并表明发射光子的态和空间纠缠可以通过量子比特频率进行调谐。使用正交幅度检测，我们重建了光子模式的矩和相关性，并展示了84%的态制备保真度。我们的结果为使用波导量子电动力学架构内通过量子干涉产生的巡游光子来实现量子通信和隐形传态协议提供了一条途径。
