Erwin Schrödinger Center for Quantum Science & Technology (ESQ)

In optical levitation, a nanoparticle is confined in an optical potential at high vacuum. The optical trap results in scattered photons that localizes the particle and heats its motion, but has recently also enabled quantum-limited position readout and subsequent cooling to the ground state. Here, we propose a first experiment in levitation that reverses this paradigm: An optical field enables a quantum measurement of the nanoparticle position, whose strength is tunable. Feedback control provides cooling and position stabilization of the particle, rendering a confining potential unnecessary or, as the optical field still provides a potential, secondary. More specifically, here we propose to experimentally implement optimal quantum control-based feedback stabilization of the levitated object on an optical inverted potential, where the intensity is zero (dark field). One big advantage of this innovative technique is to go beyond the main current optical levitation limitation and avoid internal heating of the levitated particle.

The ESQ Discovey grant allows me to initiate an ambitious new project in ideal conditions, therefore fostering exploration and innovation. It also gives be confidence and independence as an early carreer researcher.