Deep beneath Italy's Gran Sasso mountain, physicists have carried out a new test of a decades-old idea about why the strange rules of quantum mechanics do not show up in everyday life. The idea predicts that gravity should cause quantum superpositions to collapse, and that this collapse would produce an extremely faint radiation signal.
The researchers searched for that signal in what is described as one of the toughest experimental tests of the hypothesis yet. The experiment was designed to detect the faint radiation that would be expected if gravity were responsible for the disappearance of quantum behaviour.
According to the report, the results suggest that gravity may not be the answer.