Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany.
Faculty of Physics, University of Warsaw, Pasteura 5, PL02-093 Warsaw, Poland.
Phys Rev Lett. 2018 Apr 6;120(14):140407. doi: 10.1103/PhysRevLett.120.140407.
The development of solid-state quantum technologies requires the understanding of quantum measurements in interacting, nonisolated quantum systems. In general, a permanent coupling of detectors to a quantum system leads to memory effects that have to be taken into account in interpreting the measurement results. We analyze a generic setup of two detectors coupled to a quantum system and derive a compact formula in the weak-measurement limit that interpolates between an instantaneous (text-book type) and almost continuous-detector dynamics-dependent-measurement. A quantum memory effect that we term "system-mediated detector-detector interaction" is crucial to observe noncommuting observables simultaneously. Finally, we propose a mesoscopic double-dot detector setup in which the memory effect is tunable and that can be used to explore the transition to non-Markovian quantum measurements experimentally.
固态量子技术的发展需要理解相互作用的、非孤立的量子系统中的量子测量。一般来说，探测器与量子系统的永久耦合会导致记忆效应，在解释测量结果时必须考虑到这些效应。我们分析了两个探测器与量子系统耦合的通用设置，并在弱测量极限下推导出一个紧凑的公式，该公式在瞬时（教科书类型）和几乎连续的探测器动力学相关测量之间进行插值。我们称之为“系统介导的探测器-探测器相互作用”的量子记忆效应对于同时观察非对易可观测量至关重要。最后，我们提出了一个介观双点探测器设置，其中记忆效应是可调的，可以用于实验探索向非马尔可夫量子测量的转变。
