43rd Rosenthal Lecture: Prof. Francesca Ferlaino, University of Innsbruck, “Supersolidity in the ultracold: when atoms behave as crystal and superfluid at the same time”

Event time: 
Monday, March 30, 2020 - 3:30pm to 4:30pm
Location: 
Sloane Physics Laboratory (SPL), Room 59 See map
217 Prospect Street
New Haven, CT 06511
Event description: 

“Supersolidity in the ultracold: when atoms behave as crystal and superfluid at the same time”
Approaching temperatures near the absolute zero, i.e. the lowest temperature in the whole universe, the atoms develop extreme behaviors, which challenge our understanding. They can realize novel forms of matter, which leave apart the rules of classical physics entering a regime dominated by quantum mechanics. Ultracold atoms and quantum gases are becoming ever more enabling with the increasingly fine control acquired over the system’s properties and inter-particle interactions. Recently, a novel class of atomic species, possessing an exceptionally large magnetic moment has entered the stage, offering a new conceptual twist for the field. A gas of hundred thousand magnetic atoms realizes a dipolar quantum fluid in which particles interact over long-distance and in an anisotropic fashion. Rooting on such many-body dipolar interaction, new states of matter can appear.
This talk presents our recent experimental studies with either ultracold erbium or dysprosium atoms, leading to the counter-intuitive observations of a quantum gas starting behaving as a liquid-like droplet and of a soft excitation mode, so-called roton mode, which signalizes a crystallization instability in the gas.
Finally, we will discuss how the interplay between droplets and roton physics has carried us to the observation of the paradoxical and long searched supersolid phase of matter, in which crystalline order and superfluid flow coexist.
Host: Nir Navon (nir.navon@yale.edu)