It’s time to take a shortcut

By Anthony Kiely, PhD, UCC

Picture the scene. You’re in the pub with your friends and you’ve gotten a drink from the bar. You’re eager to get back to them but also very conscious of spilling your drink. You want to go at a goldilocks speed. Not too fast, not too slow. You don’t want to spill your drink, but you don’t want to walk at a snail’s pace and miss all the fun either.

So what do you do? You realise you could tilt the glass back and forth as you walk to counteract for the sloshing motion the liquid gets as you walk. You might look like you’ve drank more than you have, but you’ll get there much faster than a snail and won’t spill anything.

As you might have already guessed, moving drinks around isn’t exactly what I research. I work in theoretical quantum physics which describes objects at very small scales such as atoms and molecules. We find that things like atoms often behave much more like waves (like the sloshing water in the glass), than solid particles. Recently there has been a lot of interest in controlling individual atoms, which has been part of what I work on.

So what would be the most basic thing you could do with an atom? You could confine it (i.e. put it in a “glass”) and move it from one place to another. Ideally this would be done without it spilling out of the “glass” or taking a long time to get to its destination.

There are two options to achieve this. You could either move the atom very slowly (or adiabatically) so you don’t “spill” it. Alternatively you could do an analogous complicated tilting back and forth of the “glass” known as a shortcut to adiabaticity. These shortcuts were the topic of my Ph.D. research.

I used these shortcut methods to design a fast way to create an array of cold atoms which behave like vortices. In our water analogy, a vortex is a lot like the whirlpool you get when you pull the plug in a bathtub. These were created by shaking the “glass” the atoms were in back and forth in just the right way to create the circular motion of a vortex. This arrangement of atoms is useful for simulating complicated materials, such as transition metal oxides. This is because the behaviour of the atoms in an egg crate shaped “glass” can be shown to be very similar to how bound electrons in solids behave. However cold atoms are much easier to control and image.

It is predicted that many technologies which exploit the wavelike behaviour of atoms will emerge in the near future. The European Union will launch a flagship program in quantum technologies worth 1 billion euros in 2018. Companies such as Google, Microsoft and IBM are also getting in on the act, so expect to hear much more quantum physics in the news!

Link to journal article.

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