Despite the importance of the measurement process within the theory, it still holds unanswered questions: Does a quantum state collapse instantly during measurement? And if not, how much time does the measurement process take and what is the quantum state of the system at any intermediate step?


A collaboration of researchers from Sweden, Germany and Spain has answered these questions using a single atom. By producing a film consisting of pictures taken at different times of the measurement they showed that the change of the state happens gradually under the measurement influence. They also showed that some quantum states can be unaffected by the measurement process. These findings shed new light onto the inner workings of Nature and are consistent with the predictions of modern quantum physics.


Read the original article: Fabian Pokorny, et al. Tracking the dynamics of an ideal quantum measurement.