# Multi-path photon-phonon converter in optomechanical system at single-quantum level

## TL;DR

This paper proposes a controllable multi-path photon-phonon converter at the single-quantum level using a quadratically coupled optomechanical system, enabling high-fidelity quantum state transfer under current experimental conditions.

## Contribution

It introduces a novel scheme for multi-path photon-phonon conversion in optomechanics, incorporating an auxiliary mechanical oscillator to enhance nonlinear effects and achieve controllable quantum state transfer.

## Key findings

- High-fidelity state transfer from photon to phonon states achieved.
- The scheme operates effectively even when single-photon coupling is much smaller than mechanical frequency.
- The multi-path converter can be controlled via adjustable experimental parameters.

## Abstract

Based on photon-phonon nonlinear interaction, a scheme is proposed to realize a controllable multi-path photon-phonon converter at single-quantum level in a composed quadratically coupled optomechanical system. Considering the realization of the scheme, an associated mechanical oscillator is introduced to enhance the effective nonlinear effect. Thus, the single-photon state can be converted to the phonon state with high fidelity even under the current experimental condition that the single-photon coupling rate is much smaller than mechanical frequency ($g\ll\omega_m$). The state transfer protocols and their transfer fidelity are discussed both analytically and numerically. A multi-path photon-phonon converter is designed, by combining the optomechanical system with low frequency resonators, which can be controlled by experimentally adjustable parameters. This work provides us a potential platform for quantum state transfer and quantum information processing.