Cavity quantum phonon dynamics
Aalto University, Centre for Quantum Engineering
60° 12' 19.7676" N, 24° 39' 21.24" E
Large bodies usually follow the classical equations of motion. Deviations from this can be called
macroscopic quantum behavior. These phenomena have been experimentally verified with cavity Quantum Electro Dynamics (QED), trapped ions, and superconducting Josephson junction systems. Recently, evidence was obtained that also moving objects can display such behavior. These objects are micromechanical resonators (MR), which can measure tens of microns in size and are hence quite macroscopic. The degree of freedom is their vibrations: phonons.
The project focuses on experimental research in order to push quantum mechanics closer to the classical world than ever before. I try find quantum behavior in the most classical objects, that is, slowly moving bodies. I will use MR's, accessed via electrical resonators. Part of it will be in analogy to the previously studied macroscopic systems, but with photons replaced by phonons. The experiments are done in a cryogenic temperature mostly in dilution refrigerator. The work will open up new perspectives on how nature works, and can have technological implications.
The first basic setup is the coupling of MR to microwave cavity resonators. This is a direct analogy to
optomechanics, and can be called circuit optomechanics. The goals will be phonon state transfer via a cavity bus, construction of squeezed states and of phonon-cavity entanglement. The second setup is to boost the optomechanical coupling with a Josephson junction system, and reach the single-phonon strong-coupling for the first time. The third setup is the coupling of MR to a Josephson junction artificial atom. Here we will access the MR same way as the motion of a trapped ions is coupled to their internal transitions. In this setup, I am proposing to construct exotic quantum states of motion, and finally entangle and transfer phonons over mm-distance via cavity-coupled qubits. I believe within the project it is possible to perform rudimentary Bell measurement with phonons.