A Majorana look-alike

Mesoscopic Physics Most experimental claims of Majorana bound states, unusual quasiparticles that may become the cornerstone of topological quantum computing, rest on the observation of a persistent zero bias peak (ZBP) in tunneling spectra. In semiconductor–superconductor heterostructures, this feature may also be caused by the topologically trivial Andreev bound states. Valentini et al. provide comprehensive evidence that the ZBPs observed in their experiments with semiconductor nanowires fully coated with a superconducting shell are indeed of this topologically trivial origin, in contrast to the interpretation of similar earlier experiments. The researchers identify the length of the tunnel junction in their devices as a crucial experimental parameter. Science , abf1513, this issue p. [82][1] [1]: /lookup/doi/10.1126/science.abf1513