The proximity effect of superconductivity on confined states in semiconductors gives rise to various bound states such as Andreev bound states (ABSs), Andreev molecules and Majorana zero modes. While such bound states do not conserve charge, their Fermion parity is a good quantum number. One way to measure parity is to convert it to charge first, which is then sensed. In this work, we sense the charge of ABSs and Andreev molecules in an InSb-Al hybrid nanowire using an integrated quantum dot operated as a charge sensor. We show how charge sensing measurements can resolve the even and odd states of an Andreev molecule, without affecting the parity. Such an approach can be further utilized for parity measurements of Majorana zero modes in Kitaev chains based on quantum dots.
@article{arxiv.2311.02001,
title = {Charge sensing the parity of an Andreev molecule},
author = {David van Driel and Bart Roovers and Francesco Zatelli and Alberto Bordin and Guanzhong Wang and Nick van Loo and Jan Cornelis Wolff and Grzegorz P. Mazur and Sasa Gazibegovic and Ghada Badawy and Erik P. A. M. Bakkers and Leo P. Kouwenhoven and Tom Dvir},
journal= {arXiv preprint arXiv:2311.02001},
year = {2025}
}