Quantum Control of a Levitated Nanoparticle

Optical fields exert both conservative and non-conservative forces on polarizable objects. These forces are used in optical tweezers to control and manipulate the motion of atoms, molecules or nanoparticles. In this presentation I discuss our experiments with optically levitated nanoparticles in ultrahigh vacuum, which provides splendid isolation from the environment. Using feedback control we cool the particle's center-of-mass motion to its quantum ground state and observe quantum signatures in the spectrum of the scattered light. Our goal is to generate macroscopic quantum superpositions by placing the particle into two locations at once. This will allow us to test quantum collapse models and the interface of quantum mechanics and gravity.