We demonstrate coherent control of a three-electron exchange-only spin qubit with the quantum dots arranged in a close-packed triangular geometry. The device is tuned to confine one electron in each quantum dot, as evidenced by pairwise charge stability diagrams. Time-domain control of the exchange coupling is demonstrated and qubit performance is characterized using blind randomized benchmarking, with an average single-qubit gate fidelity F = 99.84%. The compact triangular device geometry can be readily scaled to larger two-dimensional quantum dot arrays with high connectivity.
@article{arxiv.2406.03705,
title = {Coherent control of a triangular exchange-only spin qubit},
author = {Edwin Acuna and Joseph D. Broz and Kaushal Shyamsundar and Antonio B. Mei and Colin P. Feeney and Valerie Smetanka and Tiffany Davis and Kangmu Lee and Maxwell D. Choi and Brydon Boyd and June Suh and Wonill D. Ha and Cameron Jennings and Andrew S. Pan and Daniel S. Sanchez and Matthew D. Reed and Jason R. Petta},
journal= {arXiv preprint arXiv:2406.03705},
year = {2025}
}