Fundamental physics and applications with quantum levitated optomechanics

Cold nanoscale objects levitated by optical, magnetic and electric fields in high vacuum are a new type of macroscopic quantum system, showing extraordinary sensitivity to weak forces [1]. They are currently used by our group (T. Monteiro and P. F. Barker) to search for dark matter [2], while also showing great promise for probing other fundamental interactions, including the quantum nature of gravity [3].

Using these mechanical quantum systems, we are also developing real-world applications, including sensitive, low-drift, inertial sensors, as well as detectors of extremely weak elec-trical and magnetic forces. We also use this expertise for detailed characterization of single isolated nanoparticles [4]. Most recently we have demonstrated a miniature levitated sen-sor with outstanding sensitivity to low-frequency electromagnetic waves of practical use for communication through water and the ground.

A nanoparticle trapped in an optical field in high vacuum can be decoupled, almost per-fectly, from its room temperature environment. We use light to damp and cool the motion of these objects [5,6], with experiments already demonstrating cooling to the quantum ground state [7,8]. Now there is significant effort worldwide to create non-classical states of motion such as a quantum superposition of a single nanoparticle [9], and entanglement in systems comparable to the size of a virus. These breakthroughs are key ingredients for understand-ing the classical quantum divide, and for probing the quantumness of gravity.

Our research group is working on joint theory-experiment projects which offer a range of opportunities for PhD study in theoretical, experimental and computational physics. A PhD project can be tailored for candidates that evidence aptitude and interest in one or more of the areas outlined above.