Prof. Lukas Novotny, ETH Zürich
I discuss our experiments with optically levitated nanoparticles in ultrahigh vacuum. Using both active and passive feedback techniques we cool the particle’s center-of-mass temperature to T∼100μK and reach mean quantum occupation numbers of n∼15. I show that mechanical quality factors of Q = 109 can be reached and that damping is dominated by photon recoil heating. The vacuum-trapped nanoparticle forms an ideal model system for studying non-equilibrium processes, nonlinear interactions, and ultrasmall forces.