I re-read the article, and combined with your answer, it makes much more sense now. What was originally confusing me, was how the scientists were confirming the

I re-read the article, and combined with your answer, it makes much more sense now. What was originally confusing me, was how the scientists were confirming the presence of tunneling when the laser was off. I was mistakenly assuming that they were using some special method to infer that tunneling was taking place. But of course they don't need to, like you said. The tunneling can be inferred from the change in positions of atoms in different photographs. They don't actually need to see the actual tunneling in-progress (even if it were somehow possible/not very difficult to do so). Makes sense. Thanks for that answer, it's very helpful for someone like me whose last brush with quantum physics was the physics/chemistry courses in year 1 of engineering. Cheers