Extending the coherence lifetime of a qubit is central to the implementation and deployment of quantum technologies, particularly in the solid-state where various noise sources intrinsic to the material host play a limiting role. Here, we theoretically investigate the coherent spin dynamics of a hetero-spin system formed by a spin S=1 featuring a non-zero crystal field and in proximity to a paramagnetic center S'=1/2. We capitalize on the singular energy level structure of the dyad to identify pairs of levels associated to magnetic-field-insensitive transition frequencies, and theoretically show that the zero-quantum coherences we create between them can be remarkably long-lived. Further, we find these coherences are selectively sensitive to 'local' - as opposed to 'global' - field fluctuations, suggesting these spin dyads could be exploited as nanoscale gradiometers for precision magnetometry or as probes for magnetic-noise-free electrometry and thermal sensing.
@article{arxiv.2306.17273,
title = {Quantum sensing via magnetic-noise-protected states in an electronic spin dyad},
author = {Carlos A. Meriles and Pablo R. Zangara and Daniela Pagliero},
journal= {arXiv preprint arXiv:2306.17273},
year = {2023}
}