Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université Pierre et Marie Curie, Université Denis Diderot 24, rue Lhomond, 75231 Paris Cedex 05, France.
CNRS and Université Grenoble Alpes, Institut Néel, 38042 Grenoble, France.
Phys Rev Lett. 2014 May 9;112(18):180402. doi: 10.1103/PhysRevLett.112.180402. Epub 2014 May 5.
The fluorescence of a resonantly driven superconducting qubit is measured in the time domain, providing a weak probe of the qubit dynamics. Prior preparation and final, single-shot measurement of the qubit allows us to average fluorescence records conditionally on past and future knowledge. The resulting interferences reveal purely quantum features characteristic of weak values. We demonstrate conditional averages that go beyond classical boundaries and probe directly the jump operator associated with relaxation. The experimental results are remarkably captured by a recent theory, which generalizes quantum mechanics to open quantum systems whose past and future are known.
我们在时域测量了共振驱动超导量子比特的荧光，这为研究量子比特动力学提供了一个微弱的探针。通过对量子比特进行先制备和最终的单次测量，我们可以根据过去和未来的知识对荧光记录进行平均。由此产生的干涉揭示了与弱值相关的纯粹量子特征。我们展示了超越经典边界的条件平均值，并直接探测与弛豫相关的跳跃算子。实验结果与最近的一种理论非常吻合，该理论将量子力学推广到了过去和未来已知的开放量子系统。
