Bringing order through disorder: Localization of errors in topological quantum memories

Understand

Anderson localization emerges in quantum systems when randomised parameters cause the exponential suppression of motion.

• Here we consider this phenomenon in topological models and establish its usefulness for protecting topologically encoded quantum information.
• For concreteness we employ the toric code.
• It is known that in the absence of a magnetic field this can tolerate a finite initial density of anyonic errors, but in the presence of a field anyonic quantum walks are induced and the tolerable density becomes zero.