# Spin-Mechanical Scheme with Color Centers in Hexagonal Boron Nitride Membranes

## TL;DR

This paper proposes a spin-mechanical system using color centers in hexagonal boron nitride membranes, enabling ground state cooling, quantum state preparation, and exploration of ultrastrong coupling regimes with potential for advanced quantum physics studies.

## Contribution

It introduces a novel spin-mechanical platform based on hBN membranes with detailed analysis of spin-motion interactions and quantum state control capabilities.

## Key findings

- Identification of a spin doublet ground state in hBN membranes
- Demonstration of ground state cooling of the mechanical resonator
- Proposal for generating multicomponent cat and squeezed states

## Abstract

Recently observed quantum emitters in hexagonal boron nitride (hBN) membranes have a potential for achieving high accessibility and controllability thanks to the lower spatial dimension. Moreover, these objects naturally have a high sensitivity to vibrations of the hosting membrane due to its low mass density and high elasticity modulus. Here, we propose and analyze a spin-mechanical system based on color centers in a suspended hBN mechanical resonator. Through group theoretical analyses and ab-initio calculation of the electronic and spin properties of such a system, we identify a spin doublet ground state and demonstrate that a spin-motion interaction can be engineered which enables ground state cooling of the mechanical resonator. We also present a toolbox for initialization, rotation, and readout of the defect spin qubit. As a result the proposed setup presents the possibility for studying a wide range of physics. To illustrate its assets, we show that a fast and noise resilient preparation of a multicomponent cat state and a squeezed state of the mechanical resonator is possible; the latter is achieved by realizing the extremely detuned, ultrastrong coupling regime of the Rabi model, where a phonon superradiant phase transition is expected to occur.