Inside Microsofts new transistor for the quantum age

Microsoft has introduced a new material into the realm of quantum computing, aiming to develop a scalable quantum processor with millions of fault-tolerant qubits. Referred to as a "transistor for the quantum age," the Majorana 1 utilizes a 'topoconductor' material capable of observing and controlling Majorana quasiparticles to enhance the reliability and scalability of qubits. This breakthrough by Microsoft is significant as these quasiparticles have not been formally identified yet.

The Majorana particles, composed of both themselves and antiparticles, can be scaled up to a million qubits, according to the company. By employing a stack of superconducting indium arsenide and aluminum nanowires, meticulously designed and fabricated by Microsoft atom by atom, the Majorana quasiparticles are generated at temperatures below 10K (-163 °C).

A recent paper published in Nature delves into the measurement of the topological qubit's unique quantum properties. However, Nature highlights that this does not definitively prove the existence of the quasiparticles. In 2021, a Microsoft team at TU Delft retracted a paper detailing the technology. Chetan Nayak, a Microsoft technical fellow, emphasized the importance of leveraging this new state of matter to revolutionize quantum computing on a large scale.

The topological qubit architecture involves aluminum nanowires interconnected to form an H shape. Each H structure contains four controllable Majorana quasiparticles, constituting one qubit. These H structures can be interconnected and arranged across the chip in tiles.

“We took a step back and said ‘OK, let’s invent the transistor for the quantum age. What properties does it need to have?’” Nayak explained. “And that’s really how we got here – it’s the particular combination, the quality, and the important details in our new materials stack that have enabled a new kind of qubit and ultimately our entire architecture.”

The Majorana 1 chip integrates qubits and surrounding control electronics, fitting in the palm of one's hand and seamlessly slotting into a quantum computer deployable within Azure data centers. Nayak emphasized the necessity for any quantum endeavor to have a roadmap to a million qubits to tackle significant challenges effectively. Microsoft has outlined a clear path to achieving this milestone.

This development aligns with the progress made by D-Wave in developing topological qubits, as reported by eeNews Europe. Markus Pflitsch, founder and CEO of Swiss quantum developer Terra Quantum, hailed Microsoft's custom chip utilizing topological qubits as a significant industry advancement, bringing fault-tolerant quantum hardware closer to reality than many anticipate.

The architecture's digital qubit control significantly simplifies the design of large-scale quantum machines. Microsoft has been selected as one of two companies to advance to the final phase of DARPA’s Underexplored Systems for Utility-Scale Quantum Computing (US2QC) program, a part of DARPA’s broader Quantum Benchmarking Initiative.

Furthermore, Microsoft has collaborated with Quantinuum and Atom Computing on existing qubit technologies like trapped ions within its Azure cloud service, showcasing its commitment to advancing quantum computing capabilities.