Phonons as transporters of quantum information

Phonons, and in particular surface acoustic wave phonons, have been proposed as a means to coherently couple distant solid-state quantum systems. Recent experiments have shown that superconducting qubits can control and detect individual phonons in a resonant structure, enabling the coherent generation and measurement of complex stationary phonon states. Here, I will describe our recent experiments demonstrating the deterministic emission and capture of itinerant surface acoustic wave phonons, enabling the phonon-mediated transfer of quantum states between two qubits, including the high-fidelity quantum entanglement of two superconducting qubits. If time permits, I will also describe a follow-on experiment that shows the phonon version of the optical ``quantum eraser'' experiment.