An ion trap could control atoms for quantum experiments
Y. Colombe/National Institute of Standards and Technology/Science Photo Library
“One motivation (for our experiment) is really trying to understand the fundamental physics. We’re just trying to understand the basic states that might be the case,” says Alexander Shukert At the University of Maryland.
He and his colleagues used electromagnetic fields to arrange 23 ions in a line, forming a nearly one-dimensional chain. This device can be used for quantum computing, but in this case, the researchers used the chain as a simulator.
Within it, he built it one atom at a time. Previous calculations predicted that this type of magnet would demagnetize when heated, thanks to quantum effects. But no previous experiment had achieved this phase transition.
One reason for the difficulty is that systems like quantum computers and simulators usually only work well when they are very cold. Heating them enough to cause a phase transition can thus lead to malfunction, Schukert says.
To avoid this, he and his colleagues tuned the initial quantum state of the atoms so that, as time passed, the collective state of the 1D magnet changed as its temperature increased. This revealed phase transitions never seen before.
The achievement is very exotic because chains of atoms should not normally undergo phase transitions, Mohammed Magrebi At Michigan State University. The researchers were only able to engineer it because they could make each ion interact with others that were far from it, even though they weren’t touching. This pushed the entire line into an unusual collective behavior.
Schuckert suggests that quantum simulators could also help explain the anomalous electrical or magnetic behavior that some materials show in the real world. But to do this, these devices need to be able to reach higher temperatures than they can today. They can currently only model very cold temperatures, but they say higher temperature simulations may be possible within five years.
And even more existing and theoretical systems could be studied if simulators could be made larger, for example by arranging the ions in two-dimensional arrays, say. andrea trombattoni At the University of Trieste in Italy. “This will suggest new physics to explore,” he says.
