A study that was once trumpeted as evidence for the existence of an exotic quantum state that could revolutionize computing has turned out to be anything but. A 2018 Nature paper1, based on work led by researchers at a Microsoft laboratory in the Netherlands, has now been officially retracted2 owing to what the authors call “insufficient scientific rigour” in the original data analysis.
The retraction is a setback for this approach to quantum computing, but scientists say it should still be possible to create and study the exotic states, known as Majorana fermions, that were the subject of the research. And researchers at Microsoft and elsewhere are still optimistic about the company’s plans to employ the phenomenon in a future quantum computer.
“Even if this is a step back, this is how we make progress,” says Ali Yazdani, a physicist at Princeton University in New Jersey.
Searching for Majoranas
Topological states have become one of the hottest areas of basic research in physics and materials science in the past decade. Theoretical physicists have predicted that in certain materials, the collective behaviour of electrons can display the properties of Majorana fermions, hypothetical elementary particles that could simultaneously be matter and antimatter.
The theory says that these collective quantum states would be topological, meaning that they would ‘remember’ how they moved around with respect to one another, in the same way that strings in a braid ‘remember’ how they were intertwined (topology is a branch of mathematics that studies knots and braids, among other things). This should make the Majorana states robust carriers of information, suitable for building a quantum computer that can do certain calculations faster than any ordinary classical computer can.
