Quantum State Engineering with Circuit Electromechanical Three-Body Interactions

TL;DR

This paper introduces a hybrid circuit quantum electrodynamical system enabling three-body interactions among photons, phonons, and qubits, facilitating advanced quantum state control and entanglement in a superconducting architecture.

Contribution

It proposes a novel hybrid system with strong three-body interactions and demonstrates its potential for ground-state cooling and creating nonclassical states.

Findings

Feasibility of cooling mechanical motion to ground state

Preparation of mechanical Fock and cat states

Generation of hybrid tripartite entangled states

Abstract

We propose a hybrid system with quantum mechanical three-body interactions between photons, phonons, and qubit excitations. These interactions take place in a circuit quantum electrodynamical architecture with a superconducting microwave resonator coupled to a transmon qubit whose shunt capacitance is free to mechanically oscillate. We show that this system design features a three-mode polariton--mechanical mode and a nonlinear transmon--mechanical mode interaction in the strong coupling regime. Together with the strong resonator--transmon interaction, these properties provide intriguing opportunities for manipulations of this hybrid quantum system. We show, in particular, the feasibility of cooling the mechanical motion down to its ground state and preparing various nonclassical states including mechanical Fock and cat states and hybrid tripartite entangled states.