SAN FRANCISCO — Microsoft unveiled an improved version of its quantum chip, Majorana 2, on June 2 at its Build conference in San Francisco. The company reported that the new chip achieves qubit parity lifetimes exceeding 20 seconds, a dramatic increase from the 1 to 12 milliseconds recorded in its predecessor, Majorana 1.
The updated chip replaces aluminum with lead as the superconductor material and modifies the semiconductor active region to a combination of indium arsenide and indium arsenide antimonide. Microsoft claims these changes deliver more than a 1,000x improvement in qubit stability and has accelerated its timeline for building a scalable, practical quantum computer to 2029—cutting its previous estimate in half.
"We’re seeing this more than 1000x improvement in this critical metric of the qubit based on this change," said Chetan Nayak, Microsoft technical fellow and corporate vice president of quantum hardware. "To create Majorana 2, the Microsoft Quantum team improved Majorana 1’s material stack to create a more stable topological phase."
A preprint paper describing the chip has been posted on Microsoft’s website and on arXiv.org but has not undergone peer review. Microsoft’s approach relies on Majorana particles—electron groups that act as single entities at the ends of superconducting wires—with two parallel wires forming a topological qubit. Information stored in pairs of these Majoranas is nonlocal, theoretically offering protection against errors.
However, some experts remain skeptical. Henry Legg, physicist at the University of St Andrews, said, "Nothing in this preprint resolves the fundamental issues." He added, "Nothing in the presented data proves the existence of a topological qubit or Majoranas in these devices." The paper presents only Z measurements, whereas demonstrating a functioning topological qubit requires both X and Z measurements.
Supporters acknowledge the advance. Kartiek Agarwal, physicist at Argonne National Laboratory, called the results "This is fantastic progress." He noted that Microsoft demonstrated a new method probing the nonlocal properties of Majoranas, supporting their authenticity.