Microsoft announced its Majorana 2 quantum chip at the Build conference. According to the announcement, the qubits are now 1,000 times more reliable than those in the previous chip – with an average qubit lifespan of 20 seconds and isolated values of up to a minute. Other common approaches measure qubit lifetimes in microseconds.
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According to Microsoft, the key technical difference to its predecessor lies in the material mix: Majorana 2 replaces the aluminum superconductor used in Majorana 1 with lead and updates the active semiconductor region to a combination of indium arsenide and indium arsenide antimonide. This change is expected to result in a significantly more robust topological phase; The so-called topological gap, which is intended to protect qubits from ambient noise and errors, is more than twice as large as its predecessor, says Microsoft. Details can be found in the scientific paper “20 Second Parity Lifetime in an InAs–Pb Tetron Device” on Majorana 2. Based on this self-reported progress, the company has halved its original roadmap and is targeting 2029 as the target date for a scalable, commercially usable quantum computer.
The components in Microsoft’s quantum processors consist of so-called tetrons, a type of topological qubit made of two superconducting nanowires with Majorana zero modes (MZMs) at their ends. MZMs are intended to robustly store quantum information about parity, i.e. the even or odd number of electrons in a topole wire. Fundamental operations are performed through measurements: each parity measurement returns a 0 or a 1.
The role of AI in development
Microsoft’s AI platform Microsoft Discovery is said to have played a key role in the development of Majorana 2. As Microsoft describes, the quantum team is said to have used agent-based AI to manage workflows, automate measurements, optimize manufacturing processes and detect previously unnoticed errors. Creating a topological state requires setting hundreds of parameters – a process that takes weeks to complete manually. AI agents are intended to significantly reduce cycle time.
DARPA program as an external touchstone
As evidence of external validation, Microsoft points to its participation in the DARPA quantum benchmarking program. DARPA included Microsoft as one of only two companies in the final phase of its quantum systems evaluation program. In this phase, Microsoft will develop a fault-tolerant prototype based on topological qubits. The assessment by DARPA experts provides at least an external framework but does not replace independent scientific verification of the central claims.
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Kontroverse um Majorana 1
The announcement must be read against the background of a burdened research history. Microsoft has been working on topological qubits based on Majorana states for around two decades – with significant setbacks. A paper published in Nature in 2018 by a Microsoft team that claimed to have demonstrated a Majorana state for the first time had to be retracted in 2021 after it emerged that the original data analysis did not meet scientific quality standards.
When it came to the successor, Majorana 1, which Microsoft presented in February 2025, the reaction from experts was divided. Numerous physicists expressed considerable doubt as to whether topological qubits actually appear in real hardware as theoretically predicted. The core dispute: whether the measured signals are clear evidence of Majorana null modes or whether they can also be explained by more conventional effects.
Microsoft’s approach is fundamentally different from that of its competitors. While Google with Willow and IBM with Nighthawk are relying on a growing number of superconducting qubits with improved error correction, Microsoft’s topological architecture is said to deliver inherently lower error rates – and thus drastically reduce the overhead for error correction. Both competitors are also targeting 2029 as the target date for fault-tolerant quantum computing.
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