Down To The Zeptosecond

Before we can learn how to harness the potential power of atoms, we need to truly understand how they work. Now, we're one step closer, as physicists have successfully recorded an internal atomic event with an accuracy of a zeptosecond (a trillionth of a billionth of a second). Their measurement is the smallest division of time ever to be observed and recorded by humans.

The incredibly quick atomic event researchers from Germany’s Max Planck Institute of Quantum Optics (MPQ) recorded is called photoionization — the exiting of an electron from a helium atom after it is struck by light. In their experiments, they used an extremely ultraviolet light pulse one attosecond-long (10-18 seconds) to excite the electrons. At the same time, they hit the atom with an infrared laser pulse for about four femtoseconds (one femtosecond equals 10-15 seconds).

That pulse was able to detect and record the electron as it left the atom within an accuracy rate up to 850 zeptoseconds (one zeptosecond equals 10-21 seconds). “Using this information, we can measure the time it takes the electron to change its quantum state from the very constricted, bound state around the atom to the free state,” lead researcher Marcus Ossiander told New Scientist. He also explained that the researchers were able to measure how the two electrons within the helium atom split the laser’s energy during their experiments.

Photoemission of an electron from the helium ground state (left panel) with a binding energy of 24.6 eV results in the liberation of the electron. Image Credit: Nature Physics

Precisely What We Need

Before this series of experiments, scientists could measure what happened after an electron left the atom, but nothing that occurred just before or during the exit. They also had a range of time they knew the process took (five to 15 attoseconds), but that wasn't nearly as precise as these new zeptosecond measurements.

"If you really want to develop a microscopic understanding of atoms, on the most basic level, you need to understand how electrons deal with each other,” according to Schultze. “The understanding of these processes within the helium atom provides us with a tremendously reliable basis for future experiments."

Any time we can improve our understanding of how atoms work on their most basic level, we pave the way for innovations in such fields as quantum computing, superconductivity, and nuclear power. Any one of those fields could have a far-reaching impact on how we live, so even the smallest steps forward in research could have major implications.

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