A hybrid atom-superconductor interface for quantum networking

混合量子系统结合了两种或更多不同的量子技术，以利用其各自的优势并克服每种量子比特类型的限制。超导电路是量子处理器很有前途的候选者，因为它们执行快速的高保真门运算，但具有短的相干时间。中性原子具有满足量子信息相干存储需求的潜力。原子跃迁发生在微波和光学频率范围内。因此，由存储器量子比特和处理器量子比特组成的结节量子系统可以通过光通道连接，形成量子网络。在理论上，高激发里德伯态原子的性质使得微波腔介导的原子系综之间的远距离纠缠和高定向光子发射成为可能。该项目的目标是开发超导和光子量子比特之间的高保真接口，以实现扩展的量子网络架构。本研究的长期目标是推进电路qed量子计算方法的进展，包括相干量子信息存储和微波到光转换。因此，通过超导微波谐振器将原子耦合到超导电路的芯片器件的产生，实现了光子量子比特的确定性纠缠。在超导共面波导（CPW）上捕获原子系综并产生长距离纠缠在实验上仍然具有挑战性，但这是构建可扩展量子网络的基本要求。

Hybrid quantum systems combine two or more disparate quantum technologies to harness their individual strengths and overcome the limitations of each qubit type. Superconducting circuits are promising candidates for quantum processors as they perform fast high-fidelity gate operations but have short coherence times. Neutral atoms have the potential to fulfill the requirement for coherent storage of quantum information. Atomic transitions occur in both, the microwave and optical frequency range. Therefore, nodular quantum systems consisting of memory and processor qubits could be connected via optical channels to form a quantum network. The properties of atoms in highly excited Rydberg states in theory enable microwave cavity mediated long-distance entanglement between atomic ensembles and highly directional photon emission.The aim of this project is to develop a high-fidelity interface between superconducting and photonic qubits to realise an expansive quantum networking architecture. The long-term goal of this research is to advance the progress of circuit-QED quantum computing approaches with the inclusion of coherent quantum information storage and microwave-to-optical conversion. Therefore, generation of a chip-based device where atoms are coupled to superconducting circuits via a superconducting microwave resonator enables and deterministic entanglement of photonic qubits. Trapping atomic ensembles above a superconducting coplanar waveguide (CPW) and generating long-distance entanglement remains experimentally challenging but is an essential requirement to build a scalable quantum network.