Development of Superconducting Qubit Circuits to Coherently Probe Majorana Zero Modes Part I: Device Theory and Design*

A proximitized semiconducting nanowire (NW) with high spin-orbit coupling is one of the most promising candidate systems to achieve a topologically protected qubit. Several proposals for achieving such a qubit use proximitized superconducting islands connected via gate-tunable Josephson junctions [1,2]. When two such islands are tuned to the topologically regime the hybridization of the Majorana zero modes at the junction give rise to the fractional Josephson coupling. This additional coupling shows as additional features in the transition spectrum.
Here we present our experimental approach to realizing a hybrid Majorana-transmon qubit system. The device design combines NW materials where signatures of Majorana zero modes have been demonstrated [3] with a cQED architecture compatible with high magnetic fields.
References:

[1] E. Ginossar et al., Nat. Commun, 5, 4772 (2014)
[2] D. Aasen et al, Phys. Rev. X, 6, 031016 (2016)
[3] M. Deng et al,. Science 354 (6319), 1557-1562 (2016)