Fig. 1: Open quantum phononics based on engineered SAW–qubit interaction.
a Schematic representing a qubit coupled to a bath of SAW phonons. The qubit (salmon) nonunitarily radiates excitations into a bath of SAW phonons (blue), where the emission rate is mediated by the electrical conductance of the SAW structure. b Image of the flip-chip qubit–SAW hybrid device mounted in a 3D microwave cavity (left), which is used for control and readout. False color optical micrograph of the acoustic resonator (right), consisting of an IDT (green), as well as acoustic Bragg mirrors (red). c Equivalent circuit model of the composite qubit–SAW system. Here CJ is the total capacitance shunting the Josephson junctions, CC is the capacitance responsible for coupling the qubit and SAW resonator, which is primarily dictated by the parallel-plate capacitance between the two substrates, and CSAW is the geometric capacitance of the SAW resonator. The complex admittance that represents the electro-mechanic response of the SAW resonator is divided into a conductance Ga(ω), as well as a susceptance Ba(ω) (see Supplementary Note 1).
