Microsoft says its researchers have found evidence of an exotic phenomenon that is key to its plans to build general-purpose quantum computers.
The phenomenon, known as Majorana’s zero mode, is expected to pave the way for topological quantum computing – the technology approach favored by Microsoft’s Azure Quantum program.
Quantum computing is a rather strange concept in itself: unlike the rigid one or zero world of classical computing, quantum computing juggles quantum bits, or qubits, which can represent ones and zeros simultaneously up to until the results are read.
Scientists say that the quantum approach can solve certain types of problems – for example, network optimization or simulations of molecular interactions – much faster than the classical approach. Microsoft Azure, Amazon Web Services, and other cloud-based services are already using hybrid systems to bring some of the benefits of the quantum approach to applications ranging from drug development to traffic management.
At the same time, Microsoft and other companies are trying to create hardware and software for “full-stack” quantum computing systems that can support a much wider range of applications. Microsoft has chosen a particularly exotic technological strategy, which consists of inducing quantum states on topological superconducting wires. To keep these quantum states stable, the wires would host localized Majorana zero modes at each end.
Majorana zero modes have been a subject of theoretical interest since 1937, but for decades they remained exclusively in the realm of theory. In 2018, a team of researchers reported creating the phenomenon, only to backtrack three years later. Other claims have also sparked controversy, casting doubt on the prospects for topological quantum computing.
Last year, an analysis of data from Azure Quantum’s experimental quantum devices found signatures suggesting Majorana zero modes were present at both ends of a precisely tuned nanowire. Other signatures in the electrical conductance data indicated the opening and closing of what is known as a topological gap – another telltale sign indicating a successful detection.
“It was suddenly breathtaking,” said Roman Lutchyn, a Microsoft partner research manager specializing in quantum simulation, in a Microsoft report on Majorana’s research. “We looked at the data, and that was it.”
Zulfi Alam, corporate vice president who leads Microsoft’s quantum computing effort, said the hardware team invited an external board of experts to review and validate the results.
Even if the results are validated, it will still take a lot of research to create topological qubits and assemble a quantum computer ready for prime time. But at least Microsoft researchers will have more confidence that they’re on the right track.
“What’s incredible is that humans have been able to design a system to demonstrate one of the most exotic pieces of physics in the universe,” said Microsoft engineer Krysta Svore, who leads the development program. company’s quantum software. “And we plan to leverage this to do the almost unthinkable – push toward a fault-tolerant quantum machine that will enable computation at an entirely new level, closer to how nature works.”
The researchers discussed their findings this month at a meeting hosted by Microsoft’s Station Q in Santa Barbara, California.
Correction for 12:30 p.m. March 17: An earlier version of this report misspelled Roman Lutchyn’s name.