AQP Seminar: Quantum acoustics in a multimode electromechanical system

Aalto Quantum Physics Seminar (Nanotalo). Speaker:  Mikael Kervinen (NEMS, Aalto)

Mechanical resonators are a promising way for interfacing qubits in order to realize hybrid quantum systems that offer great possibilities for applications. High-overtone Bulk Acoustic Resonators (HBAR) exhibit a combination of high frequency and high quality factors. They can reach their quantum ground state at dilution refrigeration temperatures and they can be strongly coupled to superconducting qubits via their piezoelectric effect. I present our experiments where the bulk acoustic phonons of the high overtone resonator are interacting with a qubit at the quantum level. With the system, we are able to demonstrate a generation of sideband transitions between the superconducting transmon qubit and the HBAR resonator utilizing the multimode nature of the system. The sideband generation is a result of a frequency modulated excitation of the qubit frequency. As flux modulation is applied to the transmon, it produces a rich spectrum of interfering qubit and mechanical sideband transitions.