2019/02/28 by D. A. Reiss, K. P. Schmidt · 1 citation
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.21468/scipostphys.6.6.078
published as SciPost Phys. 6, 078 (2019) · 45 pages, 14 figures, minor changes
arxiv created 2019/05/27 · arxiv updated 2019/06/26
We study the robustness of 3D intrinsic topogical order under external perturbations by investigating the paradigmatic microscopic model, the 3D toric code in an external magnetic field. Exact dualities as well as variational calculations reveal a ground-state phase diagram with first and second-order quantum phase transitions. The variational approach can be applied without further approximations only for certain field directions. In the general field case, an approximative scheme based on an expansion of the variational energy in orders of the variational parameters is developed. For the breakdown of the 3D intrinsic topological order, it is found that the (im-)mobility of the quasiparticle excitations is crucial in contrast to their fractional statistics.