Mechanical and superfluid properties of dislocations in solid He4
  Dislocations are shown to be smooth at zero temperature because of the effective Coulomb-type interaction between kinks. Crossover to finite temperature rougnehing is suggested to be a mechanism responsible for the softening of \he4 shear modulus recently observed by Day and Beamish (Nature, {\bf 450}, 853 (2007)). We discuss also that strong suppresion of superfuidity along the dislocation core by thermal kinks can lead to locking in of the mechanical and superfluid responses. 
D. Aleinikava, E. Dedits, A. B. Kuklov, D. Schmeltzer