Citation: Microsoft Azure Quantum "Interferometric single-shot parity measurement in an InAs-Al hybrid device." Nature (2025).
Web: https://www.nature.com/articles/s41586-024-08445-2
Tags: Hardware, Majorana-fermions
In this paper, the Microsoft quantum team makes progress along their roadmap towards a topological quantum computer. Namely, they introduce a technique which could potentially be used for readout on their future quantum devices. They show experimentally some promising signatures of its functionality.
Note, however, that they do NOT demonstrate any sort of coherence in their stored information. That is, they do not make any sort of demonstration that their two-level system is usable as a qubit. They do not perform any sort of operations on their qubit, or consider multiple qubits coupled together.
This hasn't stopped Microsoft from claiming that this device constitutes a "quantum chip", with "8 qubits". They haven't even demonstrated a single qubit, and it's not clear that they even have Majorana zero modes since what they could be observing are Andreev states deep into the topologically trivial phase:
> Kells, Graham, Dganit Meidan, and P. W. Brouwer. "Near-zero-energy end states in topologically trivial spin-orbit coupled superconducting nanowires with a smooth confinement." Physical Review B—Condensed Matter and Materials Physics 86.10 (2012): 100503.
We'll see whether or not they are actually able to make progress on their roadmap:
> Microsoft Azure Quantum, "Roadmap to fault tolerant quantum computation using topological qubit arrays", arxiv: 2502.12252 (2025)