Microsoft braids anyons into topological cubits on new Majorana quantum chip

Traditional qubits are extremely vulnerable to any change in their environment, which makes it difficult to scale up a quantum computer. But the new topological qubits need ten times less error-correction overhead, according to Microsoft. Traditional qubits also require analog controls, like turning a dial. Topological qubits, by comparison, can be controlled digitally.

“The results are real,” says Gabriel Aeppli, head of the photon science division of Switzerland’s Paul Scherrer Institute and a professor of physics at ETH Zurich. “In principle, topological approaches to quantum computing are ‘digital,’ and should scale better than more conventional approaches which can be seen as ‘analog.’”

How a topological qubit is built

Microsoft published a paper today in Nature magazine that describes how the topological qubits’ exotic quantum properties were created and how researchers were able to measure them.

The way it works is that four controllable Majoranas are joined together into the letter “H” with aluminum nanowires. Then, these individual H’s can be connected and laid on a chip, like floor tiles. “It’s complex in that we had to show a new state of matter to get there, but after that, it’s fairly simple. It tiles out. You have this much simpler architecture that promises a much faster path to scale,” said Krysta Svore, Microsoft technical fellow, in a statement.

The chips themselves are then combined with control logic and a refrigerator that keeps the whole system colder than outer space. Then, a software stack is used to program the chip and to connect with AI and classical computers – and all these individual pieces already exist, Svore said.

However, it will take years of engineering work to get everything to work together at scale, Microsoft said.