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Scientists Detect Electrons Outside Their Regular Orbits

The detection of electrons outside of their regular orbits could be harnessed to develop next-generation electronics based on thin materials and superconductors.

A common image of electrons has them locked in orbitals like planets around the Sun, but an international team of scientists observed electrons momentarily in higher energy orbits.

Co-author Prof Anatoli Kheifets of the Australian National University said it took 30 years to develop a way to detect the phenomenon predicted by quantum theory. “Scientists never thought they could observe such a rare event,” Kheifets said. “There is no simple way to look inside a molecule to see what an electron is doing there.”

The research team was able to take a very precise snapshot of pairs of electrons in the hydrogen molecule. As part of the experiment, the team used an X-ray beam to knock one of the electrons out of the molecule, causing its two atoms to separate. “Because the two electrons in the molecule are entangled, the one that was knocked out carried very precise information about the quantum state of its counterpart,” Kheifets said.

The experiment showed that both electrons in the ground-state orbital jump momentarily to a higher energy level at the same time. This is an example of quantum correlation. “This kind of correlation between electrons is normally too weak to see, but in certain circumstances can lead to remarkable behaviours such as superconductivity, which underpins high-capacity computer memory,” Kheifets said.

“The process of electron correlation in the hydrogen molecule is very rare and weak. Nevertheless, the sensitivity of the experimental technique was so great that it allowed us to very clearly visualise the pair of the electrons in the act, out of their usual character.”

Kheifets said the new method for imaging the entangled electrons could be a major boon for the study of technologically important materials, such as superconductors and thin layered structures. “With a tighter squeeze put on electrons by miniaturisation, their entanglement plays a great part. It’s the physics of the 21st century,” he said.

The research has been published in Nature Communications (https://goo.gl/MTHBMc).