Superfluidity of Grain Boundaries in Solid 4He
This is the pre-published version harvested from ArXiv. The published version is located at http://prl.aps.org/abstract/PRL/v98/i13/e135301
By large-scale quantum Monte Carlo simulations we show that grain boundaries in 4He crystals are generically superfluid at low temperature, with a transition temperature of the order of ∼0.5 K at the melting pressure; nonsuperfluid grain boundaries are found only for special orientations of the grains. We also find that close vicinity to the melting line is not a necessary condition for superfluid grain boundaries, and a grain boundary in direct contact with the superfluid liquid at the melting curve is found to be mechanically stable and the grain-boundary superfluidity observed by Sasaki et al. [Science 313, 1098 (2006)] is not just a crack filled with superfluid.
L Pollet, M Boninsegni, A Kuklov, Nikolai Prokof'ev, Boris Svistunov, and M Troyer. "Superfluidity of Grain Boundaries in Solid 4He" Physical Review Letters 98.13 (2007).
Available at: http://works.bepress.com/boris_svistunov/54