Time Redefined! Smallest Slice of Time Ever Measured. Physicists have just monumentally shifted our understanding of time and the world around us. For the first time ever, they have successfully measured changes in an atom on the level of zeptoseconds—a major leap for quantum computing and superconductivity. So, how small is a zeptosecond, exactly? A trillionth of a billionth of second—the smallest fragment of time every observed. Noun. zeptosecond (plural zeptoseconds) A unit of time equal to 0.000 000 000 000 000 000 001 seconds, that is, 10−21 second, and with symbol zs.
Einstein first proposed the photoelectric effect in 1905. He argued that the effect occurs when particles of light, known as photons, strike the electron orbiting an atom. Quantum mechanics suggest the energy from these photons is either absorbed entirely by one electron, or divided among a few of them. Though Einstein won a Nobel Prize in Physics for his theory, until now, no one has been able to know for sure how it’s decided. Though we knew that the end result is an electron flying from the bonds of it parent atom, we had only been able to measure in detail what happened after this occurred. Now, a team led by Max Planck Institute of Quantum Optics in Germany has been able to measure what happens in the unfathomably tiny amount of time before the electron leaves the atom.
The group accomplished this by firing a range of lasers at a helium atom. The team specifically picked helium atoms to study because they have just two electrons—meaning they’re complex enough to measure quantum mechanical behavior, but simple enough to spot patterns in the results. “Using this information, we can measure the time it takes an electron to change its quantum state from the very constricted, bound state around the atom to the free state,” Marcus Ossiander, one of the researchers on the project, told Rebecca Boyle at New Scientist.
In the first set of experiments, the team fired a super-short, extremely ultraviolet laser pulse at a helium atom to excite its electrons. Though the pulse lasted just 100 to 200 attoseconds, the team was able to narrow events down to a time frame of 850 zeptoseconds. The experiment showed that it takes between 7 and 20 attoseconds for the helium atom to eject one of its electrons, depending on how the electrons interact with the nucleus and each other. Finally, they were able to get insight into how the electrons divided up the laser’s energy; sometimes it was split evenly between the two, sometimes it was uneven, and sometimes, one electron took all of the energy.
The correlation between the electrons and the electromagnetic state of the laser field were among the leading factors influencing the divide. Though we’ve barely scratched the surface, this is an exciting step towards finally understanding the quantum behavior of atoms and how electrons work on an individual basis. Essentially, this is an important leap toward improving future technologies, such as superconductivity and quantum computing.
The research was been published in Nature Physics.