State Transfer Between a Mechanical Oscillator and Microwave Fields in the Quantum Regime

TL;DR

This paper demonstrates the coherent transfer, storage, and retrieval of quantum states between microwave fields and a mechanical oscillator, enabling quantum information processing with mechanical systems.

Contribution

It introduces a method to transfer itinerant microwave quantum states to and from a mechanical oscillator, achieving fast capture and retrieval in the quantum regime.

Findings

Successful quantum state transfer between microwave fields and mechanical oscillator

Storage and retrieval of quantum states at the single quanta level

Transfer process faster than the mechanical oscillator's quantum state lifetime

Abstract

Recently, macroscopic mechanical oscillators have been coaxed into a regime of quantum behavior, by direct refrigeration [1] or a combination of refrigeration and laser-like cooling [2, 3]. This exciting result has encouraged notions that mechanical oscillators may perform useful functions in the processing of quantum information with superconducting circuits [1, 4-7], either by serving as a quantum memory for the ephemeral state of a microwave field or by providing a quantum interface between otherwise incompatible systems [8, 9]. As yet, the transfer of an itinerant state or propagating mode of a microwave field to and from a mechanical oscillator has not been demonstrated owing to the inability to agilely turn on and off the interaction between microwave electricity and mechanical motion. Here we demonstrate that the state of an itinerant microwave field can be coherently transferred into, stored in, and retrieved from a mechanical oscillator with amplitudes at the single quanta level. Crucially, the time to capture and to retrieve the microwave state is shorter than the quantum state lifetime of the mechanical oscillator. In this quantum regime, the mechanical oscillator can both store and transduce quantum information.