Figure 4
From: Simple scheme for encoding and decoding a qubit in unknown state for various topological codes
(a) Subsystem surface code with qubits on the vertices. There are two classes of check operators, i.e. 2-weight operators at the boundaries (Z-type ones situated horizontally and X-type located vertically) and 6-weight check operators made by two 3-weight triangle operators merged together (and located diagonally in each cell for Z-type stabilizer generators and anti-diagonally for X-type). Logical operators (black lines) commute with every stabilizer and anticommute with each other. (b) Preparation of a lattice. Qubit to be encoded is marked by red dot. Qubits in green and blue regions are initialised in states |0〉 and |+〉, respectively.
