  The germanium (Ge) hut wire system has strong spin-orbit coupling, a long
coherence time due to a very large heavy-light hole splitting, and the
advantage of site-controlled large-scale hut wire positioning. These properties
make the Ge hut wire a promising candidate for the realization of strong
coupling of spin to superconducting resonators and scalability for multiple
qubit coupling. We have coupled a reflection line resonator to a hole double
quantum dot (DQD) formed in Ge hut wire. The amplitude and phase responses of
the microwave resonator revealed that the charge stability diagrams of the DQD
are in good agreement with those obtained from transport measurements. The DQD
interdot tunneling rate is shown to be tunable from 6.2 GHz to 8.5 GHz, which
demonstrates the ability to adjust the frequency detuning between the qubit and
the resonator. Furthermore, we achieved a hole-resonator coupling strength of
up to 15 MHz, with a charge qubit decoherence rate of 0.28 GHz. Meanwhile the
hole spin-resonator coupling rate was estimated to be 3 MHz. These results
suggest that holes of a DQD in a Ge hut wire are dipole coupled to microwave
photons, potentially enabling tunable hole spin-photon interactions in Ge with
an inherent spin-orbit coupling.
