Elusive phase change finally spotted in a quantum simulator
Researchers saw a chain of atoms in a quantum simulator go from being magnetic to not magnetic at all, the first time such a change has ever been seen in one spatial dimension
By Karmela Padavic-Callaghan
17 January 2025
An ion trap can control atoms for quantum experiments
Y. Colombe/NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY/SCIENCE PHOTO LIBRARY
After decades of looking, researchers have seen a string of atoms go through a 1D phase change so elusive that it could only happen inside a quantum simulator.
“One motivation [for our experiment] is really trying to understand fundamental physics. We’re trying to understand just the basic states that matter can be in,” says Alexander Schuckert at the University of Maryland.
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He and his colleagues used electromagnetic fields to arrange 23 ions of the element ytterbium into 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 instead.
Within it, they built a 1D ytterbium magnet one atom at a time. Previous calculations predicted this type of magnet would become unmagnetised when warmed, thanks to quantum effects. But no past experiment had achieved this phase transition.
One reason for the difficulty is that systems like quantum computers and simulators typically only work well when they are very cold. Warming them to make the phase transition occur can thus cause malfunctions, says Schuckert.
