Levitated optomechanics of nanoparticles has been demonstrated as a powerful tool for ultrasensitive force sensing and for the investigation of quantum mechanics and fundamental physics issues. One of the most intriguing opportunities is the experimental test of theories predicting the breakdown of quantum mechanics when moving from the nanoscale towards the macroscale. For instance, spontaneous wave function collapse models or gravitational reduction models have been proposed to reconcile the fuzziness of quantum mechanics with the definiteness of the macroscopic world and with gravity. In this respect, a known issue of optical levitation is the laser-induced heating of the levitated nanoparticle, which prevents experiments to be performed in an ultra-isolated low temperature environment. A possible solution is to replace optical levitation with passive magnetic levitation based on hybrid magnetic/superconductor systems. This approach has the unique potential to provide the ultimate isolation required for extremely accurate tests of quantum mechanics. 

The main goal of the project is the setup of a cryogenic levitation experiment with micromagnetic particles able to achieve extreme vibrational, electromagnetic and thermal isolation. Subsequently, this almost ideal environment will be exploited to perform fundamental physics experiments, such as the test of spontaneous collapse theories based on ultrasensitive force measurements. Superconducting Quantum Interference Devices (SQUIDs) will be employed to detect the levitated particle motion with minimal measurement heating and disturbance. A special cryostat designed to reach sub-kelvin temperature under ultrahigh vacuum conditions and ultralow vibrational noise will be available for the project. An alternative approach based on electrical trapping techniques will be also explored.

For more information, please visit our group website at http://phyweb.phys.soton.ac.uk/matterwave/html/  and contact prof. Hendrik Ulbricht (h.ulbricht@soton.ac.uk).