The Supersolid Phase of Helium-4: to flow or not to flow?
by
Prof.Matthias Troyer(ETH-Switzerlad)
→
Europe/Rome
Aula Conversi (Dip. di Fisica - Edificio G. Marconi)
Aula Conversi
Dip. di Fisica - Edificio G. Marconi
Description
Can a solid be superfluid? At first sight the answer is an obvious
"no". Solid and superfluid phases properties are as contradictory as
anything in Nature. Nevertheless there have been speculations for more
than half a century years, whether quantum mechanics can stabilize a
"supersolid" phase, a solid crystal exhibiting non-dissipative
superflow. While this phase has eluded detection for 50 years, first
experimental evidence has recently been found in experiments by Kim
and Chan. In this talk I will review the experimental evidence and
controversies around the supersolid phase of Helium and present our ab-
initio quantum Monte Carlo simulations of the superfluid properties of
solid Helium. While a perfect Helium single crystal is an insulator,
any Helium solid occurring in Nature is imperfect, and it is just
these crystal defects that allow superflow in solid Helium.