  Engineered quantum systems allow us to observe phenomena that are not easily
accessible naturally. The LEGO-like nature of superconducting circuits makes
them particularly suited for building and coupling artificial atoms. Here, we
introduce an artificial molecule, composed of two strongly coupled fluxonium
atoms, which possesses a tunable magnetic moment. Using an applied external
flux, one can tune the molecule between two regimes: one in which the
ground-excited state manifold has a magnetic dipole moment and one in which the
ground-excited state manifold has only a magnetic quadrupole moment. By varying
the applied external flux, we find the coherence of the molecule to be limited
by local flux noise. The ability to engineer and control artificial molecules
paves the way for building more complex circuits for protected qubits and
quantum simulation.
