and a Simplified Diagram of it (right)
Microsoft has just released a technical paper showing progress they have made with their topological qubit research since the APS meeting last March. Specifically, they have performed single-shot interferometric measurements of the fermion parity for the two loops designed into the tetron structure. These measurements implement Pauli-X and Z measurements of the tetron, which are critical steps for the measurement-based quantum computer they are developing. The Pauli-X measurement is accomplished with a fermion parity measure along two places in a loop containing two Majorana zero modes (MZMs) as shown in the picture above. The Pauli-Z measurement is accomplished with another fermion parity measurement in a different loop containing two Majorana zero modes (MZMs)
Initial performance metrics for these measurements indicate τX = 14.5 ± 0.3µs and τZ = 12.4 ± 0.4ms for parity switches observed in the X and Z measurement loops and assignment errors for X measurement of 16% and 0.5% for Z measurements. Future work at Microsoft to improve these performance metrics will include improvements in materials and fabrication techniques to yield larger topological gaps and achieve shorter coherence lengths.
A technical paper has been posted by Microsoft describing this work in more detail and it can be accessed it here.
July 11, 2025
