Microsoft Majorana 1

Microsoft Majorana 1 is a other quantum computer operated by Microsoft in USA. It has 8 physical qubits. It ranks 1 of 2 other machines in this table by physical qubit count. 7 sourced specs are in the spec sheet. 3 published benchmark or milestone records are listed below, each marked by who measured it.

Also known as Majorana 1, topological core chip

Microsoft says eight topological qubits are on the chip. DISPUTED: independent physicists contest that a topological qubit has been shown (see the Legg comment). Treat the count as a vendor claim; Microsoft's own next step is a 4x2 tetron array.

Spec sheet

Technical details as the builder or a paper states them, each with its own source. A blank is a fact we could not source, not a zero. Fidelity and coherence figures are in the benchmark table below.

Spec	Value	Basis	Note	Source
Processor	Majorana 1 topological-core QPU (topoconductor)	Vendor reported	Microsoft's description (19 February 2025); independent physicists dispute that a topological qubit has been shown.	azure.microsoft.com
Qubit type	Tetron: two parallel InAs-Al topological nanowires with Majorana zero modes	Vendor reported	Claimed topological qubit; the Legg comment contests the topological gap evidence for the InAs-Al devices.	azure.microsoft.com arxiv.org
Native gates	Measurement-based operations: parity readout via quantum-dot interferometry	Vendor reported	Microsoft describes digital pulses coupling nanowire ends to quantum dots, with microwave reflectometry readout, rather than a conventional gate set.	azure.microsoft.com arxiv.org
Cooling and environment	Dilution refrigerator, cooled to near absolute zero with an in-plane magnetic field	Vendor reported	The Microsoft paper reports measurements at about 2 T in-plane field in dilution refrigerators; no single operating temperature is stated.	azure.microsoft.com arxiv.org
Fabrication	Microsoft gate-defined InAs semiconductor and Al superconductor devices	Vendor reported	The paper's device uses a 6.5 nm Al strip on an InAs heterostructure with Ti/Au contacts; the foundry or site is not stated.	azure.microsoft.com arxiv.org
Successor	Microsoft Majorana 2	Vendor reported	Microsoft's June 2026 post describes Majorana 2 as following the Majorana 1 chip introduced a year earlier, with aluminum replaced by lead.	news.microsoft.com postquantum.com
Roadmap	4x2 tetron array for error detection on two logical qubits next; fault-tolerant prototype 'in years, not decades'	Vendor reported	Roadmap stated 19 February 2025, ending at a 27x13 tetron array for error correction and a million-qubit chip design target.	azure.microsoft.com

Published benchmark figures

These are numbers the builder or a paper reports for this machine, not results from a common test. The basis column says who measured them. What the metrics mean and why they are not comparable across technologies.

Metric	Value	Measured	Basis	Note	Source
Readout fidelity	99%	2025-02	Peer reviewed	Microsoft Nature 638 paper: single-shot interferometric parity readout with 1% measurement error on an InAs-Al device; contested, see Legg comment	arxiv.org

Milestone claims

Legg comment on Nature 638: Microsoft gap protocol gives inconsistent gapped or gapless results and public conductance data show no clear gap, contradicting the topological reading (2025-03-11, independent) arxiv.org
Microsoft claimed the first topological qubit, eight on chip, and DARPA US2QC final phase entry. DISPUTED by independent physicists; see the Legg comment row (2025-02-19, vendor reported) azure.microsoft.com

Timeline

2025-02-19: Announced
2025-02: First operational
2026-10-07: Status checked: operational

Comparable other machines

Closest in physical qubit count within the same technology. Counts of different qubit types are not interchangeable across technologies.

Machine	Operator	Qubits	Status
Quantum Brilliance Pawsey Accelerator	Pawsey Supercomputing Research Centre	2	operational