Figure 11

Pictorial representation of the rotated surface code. The black dots represent data qubits and the green squares ancillary qubits. The rotated surface code [30] contains all the qubits inside the solid square as well as the ancillary qubits surrounded by a black line. In this case, the rotated surface code contains 25 data qubits and 24 ancillary qubits; each ancillary qubit is used to measure exactly one stabilizer. However, one can slightly improve the resource needed by re-using ancillary qubits; we associate many of the ancillary qubits to more than one plaquette and star operator measurements. We thus remove the ancillary qubits with a yellow cross. Here we list which qubits replace the crossed qubits in the syndrome-computation circuit: qubit 2 is replaced by qubit 3, qubit 5 is replaced by qubit 6, qubit 7 is replaced by qubit 8, qubit 10 is replaced by qubit 11, qubit 13 is replaced by qubit 14, qubit 15 is replaced by qubit 16, qubit 17 is replaced by qubit 1, qubit 18 is replaced by qubit 3, qubit 19 is replaced by qubit 4, qubit 20 is replaced by qubit 12, qubit 21 is replaced by qubit 16, qubit 22 is replaced by qubit 14, qubit 23 is replaced by qubit 14, qubit 24 is replaced by qubit 6.