The toric code is a topological quantum error correcting code, and an example of a stabilizer code defined on a two-dimensional spin-lattice. It is the simplest and most well studied of the quantum double models (first studied in the context of Z2 spin liquid in 1991). It is also the simplest example of topological order—Z2 topological order. The toric code can also be considered to be a Z2 lattice gauge theory in a particular limit. (Wikipedia)