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arXiv · 2110.13881

Qubit based on spin-singlet Yu-Shiba-Rusinov states

Luka Pavešić·Rok Žitko
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Abstract

The local magnetic moment of an interacting quantum dot occupied by a single electron can be screened by binding a Bogoliubov quasiparticle from a nearby superconductor. This gives rise to a long-lived discrete spin-singlet state inside the superconducting gap, known as the Yu-Shiba-Rusinov (YSR) state. We study the nature of the subgap states induced by a quantum dot embedded between two small superconducting islands. We show that this system has two spin-singlet subgap states with different spatial charge distributions. These states can be put in a linear superposition and coherently manipulated using electric-field pulses applied on the gate electrode. Such YSR qubit could be implemented using present-day technology.

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Luka Pavešić, Rok Žitko. 2021-12-01. Qubit based on spin-singlet Yu-Shiba-Rusinov states. https://doi.org/10.1103/physrevb.105.075129

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