Squeezing and Multimode Entanglement of Surface Acoustic Wave Phonons
Gustav Andersson, Shan W. Jolin, Marco Scigliuzzo, Riccardo Borgani, Mats O. Tholén, J. C. Rivera Hernández, V. S. Shumeĭko, David B. Haviland, Per Delsing
Abstract
Exploiting multiple modes in a quantum acoustic device could enable applications in quantum information in a hardware-efficient setup, including quantum simulation in a synthetic dimension and continuous-variable quantum computing with cluster states. We develop a multimode surface acoustic wave (SAW) resonator with a superconducting quantum interference device (SQUID) integrated in one of the Bragg reflectors. The interaction with the SQUID-shunted mirror gives rise to coupling between the more than 20 accessible resonator modes. We exploit this coupling to demonstrate two-mode squeezing of SAW phonons, as well as four-mode multipartite entanglement. Our results open avenues for continuous-variable quantum computing in a compact hybrid quantum system.