Quantum guessing game uses the future to predict the past

Scientists predict accurate energy levels nine times out of 10 in study

Predictions are much easier to make with the benefit of hindsight. Scientists successfully predicted an important quantum property midway through an experiment by analyzing measurements taken before and after. The research, scheduled to appear in the Feb. 13 Physical Review Letters, demonstrates that the present can help inform researchers about unknowns in the past, even in the uncertainty-dominated quantum realm.