Violation of Heisenberg’s Measurement-Disturbance Relationship by Weak Measurements
While there is a rigorously proven relationship about uncertainties intrinsic to any quantum system, often referred to as “Heisenberg’s uncertainty principle,” Heisenberg originally formulated his ideas in terms of a relationship between the precision of a measurement and the disturbance it must create. Although this latter relationship is not rigorously proven, it is commonly believed (and taught) as an aspect of the broader uncertainty principle. Here, we experimentally observe a violation of Heisenberg’s “measurement-disturbance relationship”, using weak measurements to characterize a quantum system before and after it interacts with a measurement apparatus. Our experiment implements a 2010 proposal of Lund and Wiseman to confirm a revised measurement-disturbance relationship derived by Ozawa in 2003. Its results have broad implications for the foundations of quantum mechanics and for practical issues in quantum measurement.
在量子力学里，明确位置与明确动量的量子态并不存在。但不确定性原理最初被海森贝格解释为一种观察者效应（measurement-disturbance relationship）： 粒子位置的测量必然地扰乱了粒子的动量；反过来说也对，粒子动量的测量必然地扰乱了粒子的位置。
观察者效应（measurement-disturbance relationship）的不确定性原理已经被实验打破。 多伦多大学（ the University of Toronto）量子光学研究小组的李·罗泽马（ Lee Rozema）设计了一种测量物理性质的仪器，其研究成果发表在2012年9月7日当周的《物理评论通讯》（Physical Review Letters）周刊上。
为了达到这个目标，需要在光子进入仪器前进行测量，但是这个过程也会造成干扰。为了解决这个问题，罗泽马及其同事使用一种弱测量技术（weak measurement），让所测对象受到的干扰微乎其微，每个光子进入仪器前，研究人员对其弱测量，然后再用仪器测量，之后对比两个结果。发现造成的干扰不像海森贝格原理中推断的那么大。这一发现是对海森贝格理论的挑战。
