Fig. 3: Noise properties of BB codes.
From: High-threshold and low-overhead fault-tolerant quantum memory
a, Logical versus physical error rate for small examples of BB LDPC codes. A numerical estimate of pL (diamonds) was obtained by simulating d syndrome cycles for a distance-d code. Most of the data points have error bars roughly equal to pL/10 due to sampling errors. b, Comparison between the BB LDPC code [[144, 12, 12]] and surface codes with 12 logical qubits and distance d ∈ {9, 11, 13, 15}. The distance-d surface code with 12 logical qubits has the length n = 12d2 because each logical qubit is encoded into a separate d × d patch of the surface code lattice.
