CM In the literature: contested

Has a semiconductor nanowire reached the topological superconducting phase

In plain words

Many experiments on superconductor-coated semiconductor wires saw signals expected from Majorana modes, but ordinary bound states caused by disorder give similar signals, so it is unproven that any wire has become topological.

Precise statement

For InAs-Al or InSb-Al hybrid nanowires in a parallel magnetic field, establish whether a topological phase exists: bulk gap closing and reopening at Zeeman energy $E_Z = \sqrt{\Delta^2 + \mu^2}$, with zero-bias conductance peaks at both ends whose splitting decays exponentially with wire length. An answer is yes or no, based on three-terminal data passing pre-registered criteria that disorder simulations show trivial states cannot pass.

What would settle it

Three-terminal nonlocal conductance showing gap reopening and end-to-end correlated zero modes, reproduced across devices with data and analysis code released.

Status in the literature

Unverified note

Microsoft's topological-gap-protocol devices (Phys. Rev. B 107, 245423, 2023) were challenged in a 2025 comment (arXiv:2502.19560) arguing that the protocol outcome depends on analysis choices.