Empa team achieves breakthrough in quantum research

Empa researchers have succeeded in recreating a model of quantum mechanics that was theorized almost 100 years ago by Werner Heisenberg, who later won the Nobel Prize. This made the alternating Heisenberg model named after him real in the physical world for the first time in the history of quantum physics. According to a report by Empa, this breakthrough was achieved with the help of tiny pieces of the two-dimensional carbon material graphene.

The team at Empa's nanotech@surfaces Laboratory in Dübendorf used so-called Clar's goblets to produce this artificial quantum material for the first time. Although this nanographene molecule had already been predicted by chemist Erich Clar in 1972, it was only in 2019 that researchers from the same Empa laboratory were able to produce it for the first time.

With these goblets, the desired alternating alignment of the so-called electron spins was achieved. Spin is a fundamental quantum mechanical property of electrons and other particles, a kind of torque that, put simply, can point upwards (1) or downwards (0). The alignment of these spins could be used to realize the 1 and 0 of the qubit, the smallest unit of a quantum computer.

With the replica of the Heisenberg chain, in which the goblets were linked together on a gold surface like Lego bricks, the team managed to make many spins interact with each other in a controlled manner and also to reproduce these interactions. "We have shown that theoretical models of quantum physics can be realized with nanographenes and that their predictions can therefore be tested experimentally," says laboratory head Roman Fasel.

As project partners, chemists from the Technical University of Dresden provided the Empa team with the starting molecules for their synthesis of Clar's Goblets. And researchers from the Portuguese International Iberian Nanotechnology Laboratory contributed their theoretical expertise. Their joint study was published in the journal "Nature Nanotechnology" on October 28, 2024.