Hybrid quantum device with a carbon nanotube and a flux qubit for dissipative quantum engineering

TL;DR

This paper presents a hybrid quantum device combining a carbon nanotube and a flux qubit, demonstrating dissipative quantum engineering techniques to generate nonclassical states, including ground states, squeezed states, and Schrödinger cat states.

Contribution

It introduces a novel hybrid quantum system and shows how to produce and trap complex nonclassical states using dissipative engineering methods.

Findings

Successful sideband cooling to the ground state.

Generation of a squeezed ground state.

Creation of a long-lived Schrödinger cat-like superposition.

Abstract

We describe a hybrid quantum system composed of a micrometer-size carbon nanotube (CNT) longitudinally coupled to a flux qubit. We demonstrate the usefulness of this device for generating high-fidelity nonclassical states of the CNT via dissipative quantum engineering. Sideband cooling of the CNT to its ground state and generating a squeezed ground state, as a mechanical analogue of the optical squeezed vacuum, are two additional examples of the dissipative quantum engineering studied here. Moreover, we show how to generate a long-lived macroscopically-distinct superposition (i.e., a Schr\"odinger cat-like) state. This cat state can be trapped, under some conditions, in a dark state, as can be verified by detecting the optical response of control fields.