Data from: Certifying the quantumness of a nuclear spin qudit through its uniform precession

Spin precession is a textbook example of the dynamics of a quantum system
that exactly mimics its classical counterpart. Here we challenge this view
by certifying the quantumness of exotic states of a nuclear spin through
its uniform precession. The key to this result is measuring the
positivity, instead of the expectation value, of the x-projection of the
precessing spin, and using a spin > 1/2 qudit, that is not
restricted to semi-classical spin coherent states. The experiment is
performed on a single spin-7/2 123Sb nucleus, implanted in a silicon
nanoelectronic device, amenable to high-fidelity preparation, control, and
projective single-shot readout. Using Schrödinger cat states and other
bespoke states of the nucleus, we violate the classical bound by 19
standard deviation, proving that no classical probability distribution can
explain the statistic of this spin precession, and highlighting our
ability to prepare quantum resource states with high fidelity in a single
atomic-scale qudit.