Danner Armin, Masiello Ismaele V, Dvorak Andreas, Kersten Wenzel, Lemmel Hartmut, Wagner Richard, Hasegawa Yuji
Atominstitut, TU Wien, Stadionallee 2, 1020, Vienna, Austria.
Institut Laue-Langevin, 71 avenue des Martyrs, 38000, Grenoble, France.
Sci Rep. 2024 Oct 29;14(1):25994. doi: 10.1038/s41598-024-76167-6.
The statistical properties of the detection events constituting the interference fringes at the output of an interferometer are well-known. Nevertheless, there is still no unified view of what is happening to a quantum system inside an interferometer. Strong measurements of path operators destroy the interference effect. In weak measurements, an observable is weakly coupled to a pointer system and the resulting weak values quantify the observable by minimally disturbing the system. Previous which-way experiments with weak measurements could extract either the real or imaginary part of a single weak value with each ensemble. Here, we present the simultaneous full complex quantification of two path weak values with a single ensemble in a Mach-Zehnder neutron interferometer. Magnetic fields, oscillating with different frequencies, change the energy state in each interferometer path. The time-dependent phase between the energy states distinctly marks each path. The resulting beating intensity modulation at the interferometer output gives both path weak values. For the present experiment, the weak values' absolute value and phase directly describe the observed amplitude and phase of the intensity modulation.
构成干涉仪输出端干涉条纹的探测事件的统计特性是众所周知的。然而，对于干涉仪内部量子系统所发生的情况，仍然没有统一的观点。对路径算符的强测量会破坏干涉效应。在弱测量中，一个可观测量与一个指针系统弱耦合，并且由此产生的弱值通过对系统的最小干扰来量化该可观测量。先前使用弱测量的路径实验每次系综只能提取单个弱值的实部或虚部。在这里，我们展示了在马赫 - 曾德尔中子干涉仪中用单个系综同时对两个路径弱值进行完整的复数量化。以不同频率振荡的磁场会改变每个干涉仪路径中的能量状态。能量状态之间随时间变化的相位清晰地标记了每条路径。在干涉仪输出端产生的拍频强度调制给出了两个路径弱值。对于当前实验，弱值的绝对值和相位直接描述了所观察到的强度调制的幅度和相位。
