UC Berkeley

Integration of atomic-defect spin qubits into memory or computing remains a challengingtask due to a range of engineering problems, including microwave power delivery and material compatibility. While approaches exploiting spin-wave dipolar coupling have been explored in the past, they are reliant on Yttrium Iron Garnet (YIG), a model magnetic material which displays long spin coherence length, but cannot be integrated on-chip except under relatively restrictive conditions. Therefore, despite a growth in research interest in recent years, such hybrid quantum magnonic systems currently remain confined to laboratory conditions.

In this thesis, I will present a method by which surface acoustic wave (SAW) driven magne-toelastic waves can be used as an effective near-field antenna for interfacing with spin qubits. Beginning with a set of experiments on resonant coupling of acoustic waves to magnetic dy- namics, we will show that the magnetoelastic interaction acts as linear method of conversion of acoustic waves into magnetic dynamics at high microwave power levels. Following this, experimental results demonstrating a dipolar coupling to the nitrogen-vacancy center in di- amond will be shown, along with a set of conditions under which this dipolar coupling is dominant over incoherent off-resonant coupling mechanisms. With these conditions iden- tified, we implement them and demonstrate the phase-coherent coupling of acoustic waves to nitrogen-vacancy dynamics mediated by a magnetoelasticity in a ferromagnet. This ap- proach is in theory applicable across a wide range of materials, and offers the capability to integrate atomic qubits in a more power efficient manner compatible with commercial nanofabrication.