Multiqubit Greenberger-Horne-Zeilinger (GHZ) state preparation is demonstrated on two to eight qubits in the chain of ten 171Yb+ ions in the linear Paul trap with a sequence of single-qubit and two-qubit operations and pulsed dynamical decupling. Fidelity of the 8-qubit GHZ state is estimated to be 58.9±0.6%. The expected enhanced sensitivity of the parity oscillations phase to the analyzing pulse phase is observed. This result is a step towards a multi-ion optical clock with ytterbium ions with frequency averaging following 1/N scaling law in contrast to the slower 1/N scaling for an ensemble of independent particles in case when the decoherence is dominated by the spontaneous decay.
@article{arxiv.2504.03853,
title = {Multiqubit GHZ state preparation with $^{171}\text{Yb}^+$ ions for frequency standards},
author = {A. E. Korolkov and I. V. Zalivako and A. S. Borisenko and V. N. Smirnov and P. A. Kamenskikh and I. A. Semerikov and K. Yu. Khabarova and N. N. Kolachevsky},
journal= {arXiv preprint arXiv:2504.03853},
year = {2025}
}