The Supersolid Phase of Matter
Institute for Theoretical Physics, ETH Zurich
4-5 p.m., Thursday, 24 May, 2007
of Physics Common Room
Room 64, Old Main Building
University of New South Wales
nearly half a century the supersolid phase of matter has remained mysterious,
not only eluding experimental observation, but also generating a great
deal of controversy among theorists. The recent discovery of a non-classical
moment of inertia at low temperature in solid Helium-4 [1,2] has stirred
much excitement as a possible first observation of a supersolid. I will
review the experiments and present our large-scale quantum Monte Carlo
simulations [3,4] of supersolid behaviour in Helium crystals. While
we find that a perfect quantum crystal of Helium is insulating ,
we also find that crystallographic defects such as grain boundaries
can carry superflow . I will finally touch on the question of what
is needed to observe a supersolid in a perfect quantum crystal.
 E. Kim and M. H.W. Chan, Nature (London) 427, 225 (2004).
 E. Kim and M. H.W. Chan, Science 305, 1941 (2004).
 M. Boninsegni et al., Phys. Rev. Lett. 97, 080401 (2006).
 L. Pollet et al., Phys. Rev. Lett. 98, 135301 (2007).
audience is invited to meet the speaker beforehand at 3.45 p.m. over
wine and cheese in the Physics Common Room.