Physicists measure the shortest time in the world in the laboratory

Short-haul flight: The experiment measured how long a light quantum needs to cross a hydrogen molecule made up of two atoms.
Image: University of Frankfurt

It takes only a few trillionths of a billionth of a second for light particles to cross a molecule with two atoms. Researchers from Frankfurt, Berlin and Hamburg measured such a short period of time.

KShort, shorter, shortest: Researchers at the University of Frankfurt, together with colleagues from Hamburg and Berlin, measured a physical process that only takes a few zeptoseconds – the propagation of light within a hydrogen molecule. A zeptosecond is a trillionth of a billionth of a second. According to the Goethe University, never before has such a short period of time been recorded in the experiment.

Reinhard Dörner’s researchers irradiated hydrogen molecules with X-ray light at the Desy accelerator center in Hamburg. They adjusted the energy of the light particles so that one of these photons was enough to knock both electrons out of the molecule in quick succession. An interference pattern was created that was measured with a special microscope developed by Dörner. This enabled the physicists to determine when a photon reached the first hydrogen atom and when the second atom was hit. There was a maximum of 247 zeptoseconds in between, depending on how far the two atoms in the molecule were from each other.

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