Quantum nature of dislocations in pure bcc Helium

Abstract

Recent experiments show the thermal growth of dislocation lines in unlta-pure bcc $^{3}$He. The activation energy for the growth of the dislocation lines is found to agree with the activation energy of mass diffusion. We propose that these dislocations are topological defects in the phase of the complex order-parameter which describes the dynamic zero-point atomic correlations, unique to the bcc phase. These is a shear strain field associated with these topological defects. We show that the smallest topological defect is a localized excitation, a loop-defect, which leads to the exponential growth of the dislocation lines with temperature.