  We report on the first realization of a novel neutral atom qubit encoded in
the metastable fine-structure states ${^3\rm{P}_0}$ and ${^3\rm{P}_2}$ of
single $^{88}$Sr atoms trapped in an optical tweezer. Raman coupling of the
qubit states promises rapid single-qubit rotations on par with the fast
Rydberg-mediated two-body gates. We demonstrate preparation, read-out, and
coherent control of the qubit. In addition to driving Rabi oscillations
bridging an energy gap of more than 17 THz using a pair of phase-locked clock
lasers, we also carry out Ramsey spectroscopy to extract the transverse qubit
coherence time $T_2$. When the tweezer is tuned into magic trapping conditions,
which is achieved in our setup by tuning the tensor polarizability of the
${^3\rm{P}_2}$ state via an external control magnetic field, we measure $T_2 =
1.2$ ms. A microscopic quantum mechanical model is used to simulate our
experiments including dominant noise sources. We identify the main constraints
limiting the observed coherence time and project improvements to our system in
the immediate future. Our work opens the door for a so far unexplored qubit
encoding concept for neutral atom based quantum computing.
