Tuesday, November 19, 2019
5:15 p.m. — room Jaures (29 rue d’Ulm)
Searching for quantum effects in macroscopic objects typically requires low temperatures, low optical and mechanical loss, and high-precision readout. Superfluid helium offers many advantages in these regards. I will describe two experiments that use superfluid optomechanical devices. In the first, superfluid fills a Fabry-Perot optical cavity. The cavity is used to monitor the quantum fluctuations of the superfluid’s acoustic modes. We find that this system is potentially suitable for single photon/phonon detection schemes, and so may provide a route to non-Gaussian quantum states in massive objects. The second experiment uses magnetic levitation to suspend a mm-scale drop of superfluid in vacuum. I will describe preliminary measurements of the drops’ formation, trapping, and evaporative cooling, as well as of their mechanical resonances and optical resonances.