Bringing order through disorder: Localization in the toric code

          @misc{ pirsa_PIRSA:10120043,
            doi = {10.48660/10120043},
            url = {https://pirsa.org/10120043},
            author = {Wootton, James},
            keywords = {Condensed Matter},
            language = {en},
            title = {Bringing order through disorder: Localization in the toric code},
            publisher = {Perimeter Institute},
            year = {2010},
            month = {dec},
            note = {PIRSA:10120043 see, \url{https://pirsa.org}}
          }
          

Abstract

Anderson localization emerges in quantum systems when randomised parameters cause the exponential suppression of motion. In this talk we will consider the localization phenomenon in the toric code, demonstrating its ability to sustain quantum information in a fault tolerant way. We show that an external magnetic field induces quantum walks of anyons, causing logical information to be destroyed in a time linear with the system size when even a single pair of anyons is present. However, by taking into account the disorder inherent in any physical realisation of the code, it is found that localization allows the memory to be stable in the presence of a finite anyon density. Enhancements to this effect are also considered using random lattices, and similar problems for anyons transported by thermal errors are considered.