Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.
Department of Physics, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
Science. 2019 Apr 26;364(6438):368-371. doi: 10.1126/science.aaw8415.
Phonons, and in particular surface acoustic wave phonons, have been proposed as a means to coherently couple distant solid-state quantum systems. Individual phonons in a resonant structure can be controlled and detected by superconducting qubits, enabling the coherent generation and measurement of complex stationary phonon states. We report the deterministic emission and capture of itinerant surface acoustic wave phonons, enabling the quantum entanglement of two superconducting qubits. Using a 2-millimeter-long acoustic quantum communication channel, equivalent to a 500-nanosecond delay line, we demonstrate the emission and recapture of a phonon by one superconducting qubit, quantum state transfer between two superconducting qubits with a 67% efficiency, and, by partial transfer of a phonon, generation of an entangled Bell pair with a fidelity of 84%.
声子，特别是表面声波声子，被提议作为一种相干地耦合远距离固态量子系统的方法。通过超导量子比特，共振结构中的单个声子可以被控制和检测，从而实现复杂的静态声子态的相干产生和测量。我们报告了巡游表面声波声子的确定性发射和俘获，从而实现了两个超导量子比特的量子纠缠。使用 2 毫米长的声子量子通信通道，相当于 500 纳秒的延迟线，我们演示了一个超导量子比特的声子发射和俘获、两个超导量子比特之间量子态转移的效率为 67%，以及通过部分声子转移生成的纠缠贝尔对的保真度为 84%。
