Quantum Interface Between Atomic and Superconducting Qubits

虽然最近在实现由几个量子比特组成的小规模量子电路方面取得了巨大进展，但研究表明，超过现有经典机器所能实现的容错量子计算机将需要数千个量子比特的网络，远远超出目前的能力。一种可能的方法涉及混合量子信息处理(QIP)网络，该网络将利用不同量子技术的独特优势。在这里，我们概述了一个研究计划，重点是发展超导腔电路和被俘获的里德堡原子之间的坚固的量子界面，这是实现原子-超导混合量子印迹的关键技术障碍。该研究计划包括以下具体的实验推进：单个原子将被捕获并被引导到与毫温超导薄膜腔体的近距离；单个被捕获的里德堡原子与腔体之间的强耦合将被光谱探测；以及超导量子比特确定性地产生单个微波光子将被用于实现原子和超导系统之间的纠缠门。囚禁原子量子比特和超导微波腔之间高保真量子接口的发展将代表着朝着混合量子计算机迈出的重要一步。这项计划将涉及本科生和研究生的广泛参与，并提供丰富的两个层面的教育机会。信息科学最近的一个显著发现是，量子力学可以为传统经典计算机上难以解决的问题提供有效的解决方案。在量子计算机中，信息存储在量子比特或“量子比特”中，它们不仅可以存在于状态0或1，还可以存在于这些状态的任意叠加中。量子计算机的强健运行既需要这些量子叠加的长寿命，也需要能够在比量子位寿命短得多的时间尺度上相互作用。对于给定的物理量子比特系统，长寿命和快相互作用速度的要求通常是相互矛盾的。一种可能的可扩展量子计算方法涉及一种优化的混合量子处理器，该处理器结合了不同量子技术的最佳方面。在这个项目中，我们正在努力开发一种混合量子处理器，它包括一个稳定的中性原子量子存储器，存储时间为1秒，以及一个能够在10纳秒量级的时间尺度上与量子比特相互作用的快速超导量子处理器。我们试图解决中性原子和超导量子技术融合的关键障碍，即囚禁原子量子比特和超导量子腔之间的牢固接口。我们计划的成功实现将代表着朝着可扩展的混合量子信息处理迈出的重要一步。这一计划将涉及本科生和研究生的广泛参与，并提供丰富的两个层次的教育机会。

While there has been tremendous recent progress in the realization of small-scale quantum circuits comprising several qubits, research indicates that a fault-tolerant quantum computer that exceeds what is possible on existing classical machines will require a network of thousands of qubits, far beyond current capabilities. One possible approach involves a hybrid quantum information processing (QIP) network that would capitalize on the unique strengths of disparate quantum technologies. Here we outline a research program focused on the development of a robust quantum interface between superconducting cavity circuits and trapped Rydberg atoms, the key technological obstacle to realization of atom-superconductor hybrid QIP. The research program includes the following specific experimental thrusts: single atoms will be trapped and guided into close proximity with a millikelvin-temperature superconducting thin-film cavity; strong coupling between single trapped Rydberg atoms and the cavity will be probed spectroscopically; and deterministic generation of single microwave photons by a superconducting qubit will be used to enable an entangling gate between the atomic and superconducting systems. The development of a high-fidelity quantum interface between a trapped atom qubit and a superconducting microwave cavity will represent a significant step towards a hybrid quantum computer. This program will involve the extensive participation of undergraduate and graduate researchers, and is rich in educational opportunities at both levels.One of the remarkable recent discoveries in information science is that quantum mechanics can lead to efficient solutions for problems that are intractable on conventional classical computers. In a quantum computer, information is stored in quantum bits or "qubits" that can exist not only in states 0 or 1, but also in arbitrary superpositions of these states. Robust operation of a quantum computer requires both long lifetimes for these quantum superpositions, along with the ability to interact qubits with one another on timescales that are much shorter than the qubit lifetime. For a given system of physical qubits, the requirements of long lifetime and fast interaction speed are generally at odds with one another. One possible approach to scalable quantum computing involves an optimized hybrid quantum processor that combines the best aspects of disparate quantum technologies. In this program, we are working toward a hybrid quantum processor that incorporates a stable neutral atom quantum memory, with storage times of order 1 second, and a fast superconducting quantum processor capable of interacting qubits on timescales of order 10 nanoseconds. We seek to address the key obstacle to the merger of neutral atom and superconducting quantum technologies, namely, a robust interface between trapped atomic qubits and superconducting quantum cavities. Successful realization of our program will represent a major step toward scalable hybrid quantum information processing. This program will involve the extensive participation of undergraduate and graduate researchers, and is rich in educational opportunities at both levels.