Physicists Have Measured “Negative Time” in Bizarre Quantum Experiment

Physicists used weak measurements in a rubidium-atom cloud to show photons can appear to have negative dwell time.

The finding compares successful photons’ transit to the expected travel time and suggests they interacted less than zero in the measured sense.

The experiment revives a long-debated quantum effect first reported decades ago.

Researchers say it highlights how weak measurements can probe quantum dynamics with minimal disturbance.