Fast Long-Distance Control of Spin Qubits by Photon Assisted Cotunneling

TL;DR

This paper presents a theoretical study of photon-assisted cotunneling in quantum dot spin qubits, enabling fast, long-distance, and spin-selective control for quantum computing applications.

Contribution

It introduces a method to enhance long-distance spin coupling via photon-assisted cotunneling, with configurations for fast, non-local qubit manipulation.

Findings

Photon-assisted cotunneling is boosted at photon-resonance conditions.

The method enables non-local spin coupling that diminishes weakly with distance.

Configurations allow for fast switching and spin echo sequences.

Abstract

We investigate theoretically the long-distance coupling and spin exchange in an array of quantum dot spin qubits in the presence of microwaves. We find that photon assisted cotunneling is boosted at resonances between photon and energies of virtually occupied excited states and show how to make it spin selective. We identify configurations that enable fast switching and spin echo sequences for efficient and non-local manipulation of spin qubits. We devise configurations in which the near-resonantly boosted cotunneling provides non-local coupling which, up to certain limit, does not diminish with distance between the manipulated dots before it decays weakly with inverse distance.