Dislocation Mobility in a Quantum Crystal: the Case of Solid $^{4}$He Renato Pessoa, ∗ S. A. Vitiello, † and Maurice de Koning ‡ (Dated: October 11, 2018) We investigate the structure and mobility of dislocations in hcp $^{4}$He crystals. In addition to fully characterizing the five elastic constants of this system, we obtain direct insight into dislocation core structures on the basal plane, which demonstrates a tendency toward dissociation into partial dislocations. Moreover, our results suggest that intrinsic lattice resistance is an essential factor in the mobility of these dislocations. This insight sheds new light on the possible correlation between dislocation mobility and the observed macroscopic behavior of crystalline $^{4}$He . arXiv:1002.0704v1 [cond-mat.mtrl-sci] 3 Feb 2010 Abstract Instituto de Física Gleb Wataghin, Caixa Postal 6165, Universidade Estadual de Campinas - UNICAMP 13083-970, Campinas, SP, Brazil 1