  In this work, we present a device consisting of two coupled transmon qubits,
each of which are coupled to an independent high-overtone bulk acoustic wave
resonator (HBAR). Both HBAR resonators support a plethora of acoustic modes,
which can couple to the qubit near resonantly. We first show qubit-qubit
interaction in the multimode system, and finally quantum state transfer where
an excitation is swapped from an HBAR mode of one qubit, to an HBAR mode of the
other qubit.
