Harrington P M, Monroe J T, Murch K W
Department of Physics, Washington University, Saint Louis, Missouri 63130, USA.
Institute for Materials Science and Engineering, Saint Louis, Missouri 63130, USA.
Phys Rev Lett. 2017 Jun 16;118(24):240401. doi: 10.1103/PhysRevLett.118.240401. Epub 2017 Jun 14.
The Zeno and anti-Zeno effects are features of measurement-driven quantum evolution where frequent measurement inhibits or accelerates the decay of a quantum state. Either type of evolution can emerge depending on the system-environment interaction and measurement method. In this experiment, we use a superconducting qubit to map out both types of Zeno effect in the presence of structured noise baths and variable measurement rates. We observe both the suppression and acceleration of qubit decay as repeated measurements are used to modulate the qubit spectrum causing the qubit to sample different portions of the bath. We compare the Zeno effects arising from dispersive energy measurements and purely dephasing "quasimeasurements," showing energy measurements are not necessary to accelerate or suppress the decay process.
芝诺效应和反芝诺效应是测量驱动的量子演化的特征，其中频繁测量会抑制或加速量子态的衰减。根据系统与环境的相互作用以及测量方法，这两种演化类型都可能出现。在本实验中，我们使用一个超导量子比特，在存在结构化噪声库和可变测量速率的情况下，描绘出这两种芝诺效应。我们观察到，随着重复测量被用于调制量子比特频谱，导致量子比特对库的不同部分进行采样，量子比特的衰减既有抑制也有加速。我们比较了由色散能量测量和纯退相“准测量”产生的芝诺效应，表明加速或抑制衰减过程并不一定需要能量测量。
