Researchers at the Department of Energy’s Lawrence Berkeley National Laboratory and their collaborators at the University of Frankfurt, Germany; Kansas State University; and Auburn University have now established that quantum particles start behaving in a classical way on a scale as small as a single hydrogen molecule.

They reached this conclusion after performing a double slit experiment, using as their two “slits” the two proton nuclei of a hydrogen molecule, only 1.4 atomic units apart (a few ten billionth of a meters).

Says Ali Belkacem of Berkeley Lab, “For researchers who are trying to build solid-state quantum computers this is both good news and bad news. The bad news is that decoherence and loss of information occur on the very tiny scale of a single hydrogen molecule. The good news is that, theoretically, the information isn’t necessarily lost — or at least not completely.”