QTF Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076, Aalto, Finland.
Nat Commun. 2022 Dec 7;13(1):7528. doi: 10.1038/s41467-022-35049-z.
The interaction-free measurement is a fundamental quantum effect whereby the presence of a photosensitive object is determined without irreversible photon absorption. Here we propose the concept of coherent interaction-free detection and demonstrate it experimentally using a three-level superconducting transmon circuit. In contrast to standard interaction-free measurement setups, where the dynamics involves a series of projection operations, our protocol employs a fully coherent evolution that results, surprisingly, in a higher probability of success. We show that it is possible to ascertain the presence of a microwave pulse resonant with the second transition of the transmon, while at the same time avoid exciting the device onto the third level. Experimentally, this is done by using a series of Ramsey microwave pulses coupled into the first transition and monitoring the ground-state population.
无相互作用测量是一种基本的量子效应，通过它可以确定光敏物体的存在，而不会发生不可逆的光子吸收。在这里，我们提出了相干无相互作用检测的概念，并使用一个三能级超导超导transmon 电路进行了实验验证。与标准的无相互作用测量设置不同，其中的动力学涉及一系列投影操作，我们的协议采用完全相干的演化，结果令人惊讶的是，成功的概率更高。我们表明，有可能确定与 transmon 的第二个跃迁共振的微波脉冲的存在，同时避免将器件激发到第三能级。在实验中，这是通过使用一系列耦合到第一个跃迁的 Ramsey 微波脉冲并监测基态种群来完成的。
