One crucial prerequisite for such experiments is the ability to measure and control the quantum dynamics of a levitated mesoscopic particle. Such control includes cooling to the motional quantum ground state, the quantum delocalisation of the nanoparticle wave-packet beyond its dimensions, motional squeezing, and ultimately creating non-Gaussian states of motion.

I will present our approach to tackling some of these challenges. I will talk about our recent proposal and demonstration [1] of a quantum-enabling 3D motion detection technique paving the way for the entire 3D ground state cooling and coherent feedback control in free space. I'll also present our work [2] using optically active nanoparticles with a unique and essential modality for levitated optomechanics: optical refrigeration to control the internal temperature in vacuum. If time permit, I will discuss the possibility of harnessing the optical forces arising from electronic resonances of optical centres embedded in the nanoparticles to trap them in a dark focus. These ''smart'' particles will enable access to the toolbox of atomic physics for the quantum manipulation of levitated mesoscopic systems.

[1] T. Dinter & al., Phys. Rev. Res. 8, 023220 (2026)

[2] C. Laplane & al., ACS Photonics, 11 (3), 963–968 (2024)