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arXiv · 2404.19679

Tuning the coherent interaction of an electron qubit and a nuclear magnon

Noah Shofer·Leon Zaporski·Martin Hayhurst Appel·Santanu Manna·Saimon Covre da Silva·Alexander Ghorbal·Urs Haeusler·Armando Rastelli·Claire Le Gall·Michał Gawełczyk·Mete Atatüre·Dorian A. Gangloff
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Abstract

A central spin qubit interacting coherently with an ensemble of proximal spins can be used to engineer entangled collective states or a multi-qubit register. Making full use of this many-body platform requires tuning the interaction between the central spin and its spin register. GaAs quantum dots offer a model realization of the central spin system where an electron qubit interacts with multiple ensembles of $\sim 10^{4}$ nuclear spins. In this work, we demonstrate tuning of the interaction between the electron qubit and the nuclear many-body system in a GaAs quantum dot. The homogeneity of the GaAs system allows us to perform high-precision and isotopically selective nuclear sideband spectroscopy, which reveals the single-nucleus electronic Knight field. Together with time-resolved spectroscopy of the nuclear field, this fully characterizes the electron-nuclear interaction for a priori control. An algorithmic feedback sequence selects the nuclear polarization precisely, which adjusts the electron-nuclear exchange interaction in situ via the electronic g-factor anisotropy. This allows us to tune directly the activation rate of a collective nuclear excitation (magnon) and the coherence time of the electron qubit. Our method is applicable to similar central-spin systems and enables the programmable tuning of coherent interactions in the many-body regime.

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Noah Shofer, Leon Zaporski, Martin Hayhurst Appel, Santanu Manna, Saimon Covre da Silva, Alexander Ghorbal, Urs Haeusler, Armando Rastelli, Claire Le Gall, Michał Gawełczyk, Mete Atatüre, Dorian A. Gangloff. 2024-04-30. Tuning the coherent interaction of an electron qubit and a nuclear magnon. https://arxiv.org/abs/2404.19679

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