An electron orbiting an excited potassium atom has been confined with radio waves to mimic the movement of the Trojan asteroids of Jupiter.
The Trojan asteroids precede and follow Jupiter as it orbits the sun, like an entourage of bodyguards around royalty. Earth’s first Trojan asteroid was recently discovered, but it’s nothing to the group that Jupiter’s got, numbering over a thousand.
Resembling this comma-shaped group of asteroids, the electron was limited to a confined “wave packet”, say researchers from Rice University, Oak Ridge National Laboratory and the Vienna University of Technology.
How’d they do it? Lasers, radio waves and supersized atoms.
Here’s a video, with my explanation below it.
First they created a Rydberg atom using ultraviolet laser. That’s a highly excited atom, where the outermost electron has jumped up from its normal orbit into a much, much higher one.
As the outer shell electron jumps outwards, the atom becomes bigger. In this case, an unimaginably small potassium atom grew as large as a full stop! Say wha? I mean, that’s HUGE!!! That’s bigger than a bacteria, than a skin cell – from ONE ATOM?! Get out!
Locating that electron, even in a supersized Rydberg atom, is no easy task. Electrons, I was told at uni, wink in and out of existence. They can act as a particle or a wave. Instead of pinning down an electron, you just predict where it’s most likely to be – called a wave function. It’s a fuzzy way of looking at things.
The team could collapse the wave function with a sequence of electric field pulses, which basically limited where the electron would be. That created the comma-shaped wave packet that resembled the Trojan asteroids.
Next job – make it move! They made the localised electron move in an orbit using radio waves, which rotated the nucleus.
But how can you check where the electron is, and measure your results, when you can’t see it?
The answer was to do it in snapshots. Each snapshots of the wave packet was made using another electric field pulse. Unfortunately, the process destroyed the Rydberg atom, so they had replicate the experiment tens of thousands of times to get enough data to complete the picture.
Seems like a lot of work to make something extremely tiny and wavy move like you want it, but who knows where research like this might lead. To have this kind of control over electons could lead to new types of chemistry, and quantum computing.