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.
在量子力學裡，明確位置與明確動量的量子態並不存在。但不確定性原理最初被海森貝格解釋為一種觀察者效應（measurement-disturbance relationship）： 粒子位置的測量必然地擾亂了粒子的動量；反過來說也對，粒子動量的測量必然地擾亂了粒子的位置。
觀察者效應（measurement-disturbance relationship）的不確定性原理已經被實驗打破。 多倫多大學（ the University of Toronto）量子光學研究小組的李·羅澤馬（ Lee Rozema）設計了一種測量物理性質的儀器，其研究成果發表在2012年9月7日當周的《物理評論通訊》（Physical Review Letters）周刊上。
為了達到這個目標，需要在光子進入儀器前進行測量，但是這個過程也會造成干擾。為了解決這個問題，羅澤馬及其同事使用一種弱測量技術（weak measurement），讓所測對象受到的干擾微乎其微，每個光子進入儀器前，研究人員對其弱測量，然後再用儀器測量，之後對比兩個結果。發現造成的干擾不像海森貝格原理中推斷的那麼大。這一發現是對海森貝格理論的挑戰。
