Majorana signatures in charge transport through a topological superconducting double-island system

TL;DR

This paper explores how charge transport measurements in a double-island system with Majorana zero modes can reveal signatures of Majorana coupling, providing methods to experimentally detect and quantify this coupling.

Contribution

It introduces a theoretical framework for using current-voltage characteristics to measure Majorana coupling in a double-island setup, including proposed experimental protocols.

Findings

$I$-$V$ characteristics reveal Majorana coupling $E_M$

Proposed dc and ac transport experiments to measure $E_M$

Intrinsic dephasing mechanisms limit measurement accuracy

Abstract

We investigate the dynamics of a charge qubit consisting of two Coulomb-blockaded islands hosting Majorana zero modes. The frequency of the qubit is determined by coherent single-electron tunneling between two islands originating from the hybridization of two Majorana zero modes localized at the junction. We calculate the sequential tunneling current $I$ through the double-island device coupled to normal metal leads. We demonstrate that the $I\!-\!V$ characteristics in the large-bias regime can be used as a measurement of the coherent Majorana coupling $E_M$. We propose dc and ac transport experiments for measuring $E_M$, and discuss their limitations due to intrinsic dephasing mechanisms such as excited quasiparticles.