Quantum control of surface acousticwave phonons
Abstract
One of the hallmarks of quantum physics is the generation of nonclassical quantum states and superpositions, which has been demonstrated in several quantum systems, including ions, solidstate qubits and photons. However, only indirect demonstrations of nonclassical states have been achieved in mechanical systems, despite the scientific appeal and technical utility of such a capability^{1,2}, including in quantum sensing, computation and communication applications. This is due in part to the highly linear response of most mechanical systems, which makes quantum operations difficult, as well as their characteristically low frequencies, which hinder access to the quantum ground state^{37}. Here we demonstrate full quantum control of the mechanical state of a macroscale mechanical resonator. We strongly couple a surface acousticwave^{8} resonator to a superconducting qubit, using the qubit to control and measure quantum states in the mechanical resonator. We generate a nonclassical superposition of the zero and onephonon Fock states and map this and other states using Wigner tomography^{914}. Such precise, programmable quantum control is essential to a range of applications of surface acoustic waves in the quantum limit, including the coupling of disparate quantum systems^{15,16}.
 Publication:

Nature
 Pub Date:
 November 2018
 DOI:
 10.1038/s4158601807195
 arXiv:
 arXiv:1804.07308
 Bibcode:
 2018Natur.563..661S
 Keywords:

 Quantum Physics
 EPrint:
 Nature 563, 661665 (2018)