%0 Electronic Article
%A Huang, Ze-Min
%A Colmenarez, Luis
%A Müller, Markus
%A Diehl, Sebastian
%T Coherent information as a mixed-state topological order parameter of fermions
%N arXiv:2412.12279
%M FZJ-2025-01525
%M arXiv:2412.12279
%D 2025
%Z 20 pages, 13+3 figures
%X Quantum error correction protects quantum information against decoherence provided the noise strength remains below a critical threshold. This threshold marks the critical point for the decoding phase transition. Here we connect this transition in the toric code to a topological phase transition in disordered Majorana fermions at high temperatures. A quantum memory in the error correctable phase is captured by the presence of a Majorana zero mode, trapped in vortex defects associated with twisted boundary conditions. These results are established by expressing the coherent information, which measures the amount of recoverable quantum information in a given noisy code, in terms of a mixed-state topological order parameter of fermions. Our work hints at a broader connection of the robustness of quantum information in stabilizer codes and mixed-state topological phase transitions in symmetry protected fermion matter.
%F PUB:(DE-HGF)25
%9 Preprint
%U https://juser.fz-juelich.de/record/1038540