Microsoft recently unveiled Majorana 1, the world’s first quantum processor powered by topological qubits. Microsoft researchers said topoconductors are a revolutionary class of materials that enables them to create topological superconductivity, a new state of matter that previously existed only in theory. The advance stems from the company’s design and fabrication of gate-defined devices that combine indium arsenide and aluminum. When cooled to near absolute zero and tuned with magnetic fields, these devices form topological superconducting nanowires with Majorana Zero Modes (MZMs) at the wires’ ends (FIGURE 1). A Majorana particle is a fermion that is its own antiparticle, first hypothesised by Ettore Majorana in 1937.
“In one of our longest running research projects, our team at Microsoft has been able to take a subatomic particle that has only been theorized until now, and not only observe it but control it, creating an entirely new material and a new architecture for quantum computing, one that can scale to millions of qubits on a single chip,” said Dr. Krysta Svore, who leads the Microsoft Quantum – Redmond (QuArC) group at Microsoft Research in Redmond, WA.
“It will solve problems unsolvable by the combined power of all the world’s compute today and promises to revolutionize fields such as medicine, material science, and our understanding of the natural world,” she said.
Microsoft made several announcements related to the new development:
- Majorana 1: the world’s first Quantum Processing Unit (QPU) powered by a Topological Core, designed to scale to a million qubits on a single chip.
- A hardware-protected topological qubit: research published in Nature that demonstrate the company’s ability to harness a new type of material and engineer a radically different type of qubit that is small, fast, and digitally controlled.
- A device roadmap to reliable quantum computation: a path from single-qubit devices to arrays that enable quantum error correction. The roadmap encompasses four generations of devices: a single-qubit device that enables a measurement-based qubit benchmarking protocol; a two-qubit device that uses measurement-based braiding to perform single-qubit Clifford operations; an eight-qubit device that can be used to show an improvement of a two-qubit operation when performed on logical qubits rather than directly on physical qubits; and a topological qubit array supporting lattice surgery demonstrations on two logical qubits. Devices that enable this path require a superconductor-semiconductor heterostructure that supports a topological phase, quantum dots and coupling between those quantum dots that can create the appropriate loops for interferometric measurements, and a microwave readout system that can perform fast, low-error single-shot measurements.
- Building the world’s first fault-tolerant prototype (FTP) based on topological qubits: Microsoft is on track to build an FTP of a scalable quantum computer—in years, not decades—as part of the final phase of the Defense Advanced Research Projects Agency (DARPA) Underexplored Systems for Utility-Scale Quantum Computing (US2QC) program.
“Together, these milestones mark a pivotal moment in quantum computing as we advance from scientific exploration to technological innovation,” Chetan Nayak, Technical Fellow and Corporate Vice President of Quantum Hardware at Microsoft in a blog post.
At the core of a quantum computer are qubits. “Qubits are like our classical bits. They are essentially zeros and ones in a transistor, and we need the analog of that in quantum computing,” said Svore. “The reason quantum computing has been so slow to progress is that the industry has been struggling with problems making qubits reliable and resistant to noise. Progress has been incremental.”
“The challenge is qubits are actually pretty delicate in general, so you need underlying qubits that are really stable, but you don’t want that to come at a cost because you don’t want your underlying qubits to be really big. That’s one way to make them more stable is have them really big, but if they’re really big and you’re still going to need many of them, then how are you going to fit them all into your system?,” Nayak said. “You don’t want to deal with something the size of a warehouse.
“The second thing is you don’t want to qubits end up being slow because if the price you pay for getting something stable is you have to go really slowly, then a computation that might take you a month ends up taking your decade and then it’s not useful,” said Nayak.
“A hundred years ago, mathematicians predicted one such new state of matter, the topological state, and since then researchers have been looking for a very specific, very useful quasi-particle within it, the Majorana particle,” Svore said. “Last year, we were able to observe it for the first time and this year we’re able to control it and use its unique properties to build a topoconductor, a new type of semiconductor that operates also as a superconductor. With this material, we can build a whole new foundational architecture for our quantum computers — a topological core — allowing us to scale to not tens or hundreds of cubits on a chip, but millions all in the palm of your hand.
Microsoft’s Dr. Mathias Troyer adds: “Majorana’s theory showed that mathematically it’s possible to have a particle that is its own antiparticle. That means you can take two of these particles and you bring them together and they could annihilate and there’s nothing left. Or you could take two particles and you bring them together and you just have two particles. Sometimes it’s nothing, the zero state, and sometimes it’s the electron, the one state.”
“It really has taken quite some some time to design a chip that can enable measurement of this literally elusive particle,” Svore said. “We’ve designed a chip that is able to measure the presence of Majorana. Majorana allows us to create a topological qubit. A topological qubit is reliable, small and controllable. This solves the noise problem that creates errors in qubits. Now that we have these topological qubits, we’re able to build an entirely new quantum architecture, the topological core, which can scale to a million topological qubits on a tiny chip.”
Click here to read the full article in Semiconductor Digest magazine.
