Driving and measurement based protocol to improve Majorana qubits

In [2,3], a series of dynamical protocols were proposed for dynamically decoupling [1] imperfect (overlapping) Majorana Zero Modes (MZMs) via periodic double braiding of MZMs from a nanowire and weakly coupled quantum dot (QD). In [2,3], the efficiency of the protocols crucially depend on the successful adiabatic Landau-Zener (LZ) transitions that periodically flip the parity of the QD thereby the nanowire which effectively realizes the double braiding of MZMs. We further improve the LZ transitions by using a spin-echo like protocol that is dynamically modified depending on the results of the measurements of the QD. By numerical simulation, we demonstrate that the novel measurement-protocol better suppresses the decoherence due to dephasing noise in Majorana qubits compared to the otherwise identical protocol in the absence of QD measurements.

[1] K. Agarwal and I. Martin, Phys. Rev. Lett. 125, 080602 (2020)

[2] I. Martin and K. Agarwal, PRX Quantum. 1 020324 (2020)

[3] B. Min, B. Fajardo, T. Pereg-Barnea, and K. Agarwal, Phys. Rev. B 105 155412 (2022)