Lab mimics Jupiter's Trojan asteroids in a single atom

Physicists have for the first time built an accurate model of part of the solar system inside a single atom of potassium.

An international team, led by Rice University, has showed in a laboratory experiment that it could cause an electron in an atom to orbit the nucleus in precisely the same way that Jupiter's Trojan asteroids orbit the sun.

The findings uphold a prediction made in 1920 by famed Danish physicist Niels Bohr about the relationship between the then-new science of quantum mechanics and Isaac Newton's tried -and-true laws of motion.

"Bohr predicted that quantum mechanical descriptions of the physical world would, for systems of sufficient size, match the classical descriptions provided by Newtonian mechanics," said team leader Barry Dunning.

He added: "Bohr also described the conditions under which this correspondence could be observed.

In particular, he said it should be seen in atoms with very high principal quantum numbers, which are exactly what we study in our laboratory."

In the experiment, the physicists began by using an ultraviolet laser to create a Rydberg atom.

Rydberg atoms contain a highly excited electron with a very large quantum number.

In the Rice experiments, potassium atoms with quantum numbers between 300 and 600 were studied.

"In such excited states, the potassium atoms become hundreds of thousands of times larger than normal and approach the size of a period at the end of a sentence.

Thus, they are good candidates to test Bohr's prediction," Dunning said.

The team said that it wanted to see if it could develop a way to use radio frequency waves to capture this localised electron and make it orbit the nucleus indefinitely without spreading out.

They succeeded by applying a radio frequency field that rotated around the nucleus itself.

This field ensnared the localised electron and forced it to rotate in lockstep around the nucleus.

Jupiter's 4,000-plus Trojan asteroids have the same orbit as Jupiter and are contained in comma-shaped clouds that look remarkably similar to the localised wave packets created in the Rice experiments.