Centre for Quantum Information and Quantum Control and Institute for Optical Sciences, Department of Physics, University of Toronto, 60 St. George Street, ON M5S 1A7, Canada.
Science. 2011 Jun 3;332(6034):1170-3. doi: 10.1126/science.1202218.
A consequence of the quantum mechanical uncertainty principle is that one may not discuss the path or "trajectory" that a quantum particle takes, because any measurement of position irrevocably disturbs the momentum, and vice versa. Using weak measurements, however, it is possible to operationally define a set of trajectories for an ensemble of quantum particles. We sent single photons emitted by a quantum dot through a double-slit interferometer and reconstructed these trajectories by performing a weak measurement of the photon momentum, postselected according to the result of a strong measurement of photon position in a series of planes. The results provide an observationally grounded description of the propagation of subensembles of quantum particles in a two-slit interferometer.
量子力学不确定性原理的一个结果是，人们可能无法讨论量子粒子所走的路径或“轨迹”，因为任何位置的测量都会不可逆转地干扰动量，反之亦然。然而，通过弱测量，可以为一组量子粒子定义一组轨迹。我们通过弱测量光子动量，将量子点发射的单个光子穿过双缝干涉仪，并根据一系列平面中光子位置的强测量结果进行后选择，从而重建这些轨迹。结果为在双缝干涉仪中传播的量子粒子的子样本提供了一种基于观测的描述。
