# Multi-phonon interactions between nitrogen-vacancy centers and nanomechanical resonators

## TL;DR

This paper explores multi-phonon interactions in a hybrid diamond system, demonstrating how engineered nonlinearities enable nonclassical mechanical states and quantum correlations, advancing quantum information processing capabilities.

## Contribution

It introduces a method to enhance nonlinear interactions via sideband engineering in NV center-resonator systems, enabling control of multi-phonon processes.

## Key findings

- Enhanced multi-phonon coupling strength achieved.
- Preparation of nonclassical mechanical states demonstrated.
- Potential applications in quantum information processing identified.

## Abstract

We investigate the multi-phonon interactions in a hybrid system composed of a nitrogen-vacancy center and a mechanical resonator.We show that, through appropriate sideband engineering analogy to the Mollow or Lamb-Dicke dynamics, the enhanced nonlinear interactions can dominate the coupled system. As an example, we show the preparation of nonclassical states of the mechanical motion and explore the quantum correlation of $n$-phonon with the engineered dissipation,based on the large multi-phonon coupling strength attainable in this sideband structure. This work takes full advantage of the structure and coherence features of defect centers in diamond, and may be useful for quantum information processing.