Demonstrating Majorana non-Abelian properties using fast adiabatic charge transfer
Svend Krøjer, Rubén Seoane Souto, Karsten Flensberg
Abstract
Demonstration of Majorana non-Abelian properties is a major challenge in the field of topological superconductivity. In this work, we propose a minimal device and protocol for testing non-Abelian properties using charge-transfer operations between a quantum dot and two Majorana bound states combined with reading the parity state using a second dot. We use an adiabatic perturbation theory to find fast adiabatic paths to perform operations and to account for nonadiabatic errors. We find the ideal parameter sweep and a region in parameter space that reduces the charge-transfer operation time 1--2 orders of magnitude with respect to constant velocity driving. Using realistic parameters, we estimate that the lower bound for the timescale can be reduced to $\ensuremath{\sim}10\phantom{\rule{0.16em}{0ex}}\mathrm{ns}$. Deviations from the ideal parameters lead to the accumulation of an undesired dynamical phase, affecting the outcome of the proposed protocol. We furthermore suggest to reduce the influence from the dynamical phase using a flux echo. The echo protocol is based on the $4\ensuremath{\pi}$ periodicity of the topological state, absent for trivial bound states.