Detecting phonon blockade with photons

TL;DR

This paper proposes a method to detect phonon blockade using photons in a superconducting microwave resonator coupled to a mechanical mode, enabling observation of quantum mechanical effects in mechanical systems.

Contribution

It introduces a strong, tunable coupling mechanism between microwave and mechanical modes for phonon detection via photon statistics, including the realization of a phonotonic Josephson junction.

Findings

Phonon blockade can be detected through cavity photon statistics.

The scheme demonstrates a phonotonic Josephson junction with coherent oscillations.

Transition between self-trapping and oscillating regimes can be controlled dynamically.

Abstract

Measuring the quantum dynamics of a mechanical system, when few phonons are involved, remains a challenge. We show that a superconducting microwave resonator linearly coupled to the mechanical mode constitutes a very powerful probe for this scope. This new coupling can be much stronger than the usual radiation pressure interaction by adjusting a gate voltage. We focus on the detection of phonon blockade, showing that it can be observed by measuring the statistics of the light in the cavity. The underlying reason is the formation of an entangled state between the two resonators. Our scheme realizes a phonotonic Josephson junction, giving rise to coherent oscillations between phonons and photons as well as a self-trapping regime for a coupling smaller than a critical value. The transition from the self-trapping to the oscillating regime is also induced dynamically by dissipation.