Physicists run one million trials to show bizarre 'negative time' quantum effect is real

Researchers in Canada and Australia used weak measurements to study how light interacts with an atomic cloud.

After about one million trials, they found results consistent with photons appearing to spend negative transit time in the medium.

The finding reinforces earlier reports of a strange quantum timing effect involving photon scattering and atom excitation.

Published in Physical Review Letters, the work suggests standard physics can produce time-travel-like behavior without breaking causality.