From Galileo to Einstein in 0.2 ̊ F Gary G. Ihas , University of Florida, DMR 1007937

1. From Galileo to Einstein in 0.2 ̊ FGary G. Ihas, University of Florida, DMR1007937 We have studied propagation of tiny nanospheres only several atoms in size through superfluid helium at temperatures very near to the absolute zero. Nothing impedes the spheres under these conditions and they move ballistically, that is with uniform speeds and in straight lines, as was concluded by Galileo. At slightly higher temperatures, however, thermal motion of the superfluid is intense enough to mimic a dense gas in which the spheres collide with the gas particles and start moving chaotically, so it takes them longer to propagate. They demonstrate behavior similar to that observed by British botanist Robert Brown for pollen suspended in water, and start obeying Einstein’s law for chaotic motion. Only a fraction of a degree is enough to see the dramatic transition from one type of motion to another. Brownian motion Ballistic motion Prediction of Einstein’s theory

2. What are tornadoes like when shrunk to atomic sizes?Gary G. Ihas, University of Florida, DMR1007937 Turbulence dominates our lives: from climate and airplanes down to toilet flushes. Using the rotating cryostat available at the University of Manchester in the UK, we were able to develop a new type of instrumentation that will help us to make visible chaotic motion of the tiniest vortices in superfluid helium at temperatures near absolute zero. They are very similar to tornadoes and cyclones in the atmosphere. Miniscule twisters, only one atom thin, they entangle inside the superfluid and set the liquid in complicated motion known as quantum turbulence. Our technique of decorating these vortices with tiny fluorescent spheres will help us see them and uncover the mysteries that turbulence has on offer. Rotating cryostat at the University of Manchester, UK