Hybrid quantum systems formed by cold atoms and levitated nanospheres

Optical potentials created by incident and scattered optical fields around a levitated nanosphere can be used for sympathetic cooling and for creating a bound nanosphere-atom system analogous to a large molecule. We demonstrate that long range potentials can be produced allowing fast sympathetic cooling of a trapped nanosphere to microKelvin temperatures using cold atoms. We also show how the center-of-mass can be controlled by manipulation of the internal state of the atom to create and detect nonclassical macroscopic motional states of the nanoparticle. Spatial superpositions can be produced that do not require ground state cooling and can be revealed using the Earth's gravitational field.