Clothier, Jacob and Zmeev, Dmitry (2025) Development of a levitating sphere for probing superfluid properties at ultra-low temperatures. Masters thesis, Lancaster University.
![[thumbnail of 2025ClothierMRes]](https://eprints.lancs.ac.uk/style/images/fileicons/text.png)
Abstract
At ultra-low temperatures 4He forms a superfluid with many interesting properties, some of which are not fully understood. Many techniques have been created that have expanded our knowledge of superfluid 4He: from oscillating discs [1] and wires [2] to linear motion grids [3] and many more. However, they have limitations from their small experimental volumes, heat release and container interference. The levitating sphere probe built at Lancaster University with the collaboration of Universidad Rey Juan Carlos aims to solve these limitations [4], [5]. Here we show the results from the initial ultra-low temperature experiments, which demonstrate its validity asa superfluid probe and potential other uses given its incredibly low intrinsic dissipation, with a free decay time constant τ > 100 ks (28.7 hours).