论文标题
多路复用光子数测量
Multiplexed photon number measurement
论文作者
论文摘要
当两个级别的系统（Qubit）用作较大系统的探针时，它自然会导致回答一个关于系统状态的单个问题。在这里，我们提出了一种方法，其中单个量子位可以提取，而不是单个量子线，而是使用连续测量的微波谐振器的光子数量的许多信息。我们通过记录反映频率梳子的超导量子置量发出的荧光来实现原则证明实验，从而实现了多重光子计数，其中关于每个Fock状态的信息（从0到8）同时在独立的测量通道中同时编码。谐振器的量子状态的直接Wigner断层扫描证明了测量的背部表现以及最佳信息提取参数。我们的实验通过用在频域中分离的同时且连续的测量取代顺序量子测量来释放量子仪的全部潜力。
When a two-level system -- a qubit -- is used as a probe of a larger system, it naturally leads to answering a single yes-no question about the system state. Here we propose a method where a single qubit is able to extract, not a single, but many bits of information about the photon number of a microwave resonator using continuous measurement. We realize a proof-of-principle experiment by recording the fluorescence emitted by a superconducting qubit reflecting a frequency comb, thus implementing multiplexed photon counting where the information about each Fock state -- from 0 to 8 -- is simultaneously encoded in independent measurement channels. Direct Wigner tomography of the quantum state of the resonator evidences the back-action of the measurement as well as the optimal information extraction parameters. Our experiment unleashes the full potential of quantum meters by replacing a sequential quantum measurements with simultaneous and continuous measurements separated in the frequency domain.
