Tootfinder

Optical Interferometric Readout of a Magnetically Levitated Superconducting Microsphere
J. J. Hansen, S. Minniberger, D. Ilk, P. Asenbaum, G. Higgins, R. G. Povey, P. Schmidt, J. Hofer, R. Claessen, M. Aspelmeyer, M. Trupke
https://arxiv.org/abs/2508.11731

Optical Interferometric Readout of a Magnetically Levitated Superconducting Microsphere
We probe the motion of a 6 $μg$ magnetically levitated superconducting microsphere using optical interferometry at 3 K, achieving a resolution better than 1 $nm/ \sqrt{Hz}$, and use the measured signal to feedback-cool its motion. The resolution exceeds the shot-noise limit of 11 $pm/ \sqrt{Hz}$ primarily due to technical noise arising from the roughness of the particle. Combined with established techniques of cavity optomechanics, the high degree of isolation from environmental noise afforded…