Microsoft Majorana 1: Topological Qubit Chip (Disputed)
On February 19, 2025, Microsoft unveiled the Majorana 1 chip — built on InAs/Al hybrid 'topoconductor' material and claiming 8 topological qubits. Microsoft asserts this architecture is scalable to 1 million qubits per chip, potentially bypassing the overhead of conventional error correction through intrinsic noise immunity.
The chip was published in Nature, but its reception was contentious: Nature's editors clarified that the paper does not constitute 'evidence of Majorana zero modes,' and 2 of 4 peer reviewers opposed publication. Whether true topological protection has been achieved remains an active scientific debate. The PQ count of 8 reflects the chip's claimed qubit count per the paper, not independently verified topological qubits.
Microsoft's long-term theory: topological qubits achieve intrinsic error protection from the material level, enabling a near 1:1 physical-to-logical qubit ratio — far more efficient than surface codes requiring ~1,000:1 overhead. Alongside this, Microsoft's partnerships with Quantinuum achieved 4 LQ (April 2024), 12 LQ (September 2024), and 48 LQ via Helios (November 2025) using Quantinuum's trapped-ion hardware.