# Hanbury Brown and Twiss interferometry of single phonons from an optomechanical resonator

## TL;DR

This paper demonstrates the generation and verification of single-phonon states in a nanomechanical resonator using optical control, confirming nonclassical phonon behavior without full state reconstruction.

## Contribution

It presents the first optical quantum control of a mechanical oscillator at the single-phonon level and verifies nonclassical states via Hanbury Brown and Twiss interferometry.

## Key findings

- Successful generation of single-phonon Fock states
- Verification of nonclassical phonon states without full tomography
- Establishment of optical control at the single-phonon level

## Abstract

Nano- and micromechanical solid-state quantum devices have become a focus of attention. Reliably generating nonclassical states of their motion is of interest both for addressing fundamental questions about macroscopic quantum phenomena and for developing quantum technologies in the domains of sensing and transduction. We used quantum optical control techniques to conditionally generate single-phonon Fock states of a nanomechanical resonator. We performed a Hanbury Brown and Twiss-type experiment that verified the nonclassical nature of the phonon state without requiring full state reconstruction. Our result establishes purely optical quantum control of a mechanical oscillator at the single-phonon level.