Dithered Belief Propagation Matches Relay-BP Accuracy on Distance-11 Surface Code While Cutting Multiplications 98 Percent
The preprint demonstrates that dithering stabilizes BP decoding for quantum memories without the heavy post-processing of OSD or Relay-BP. Evidence is limited to simulation; hardware validation and scaling to larger distances remain necessary next steps.
The method applies quantum-adapted sign flipping plus randomized prior perturbation to standard BP on qLDPC codes. Evaluated under full circuit-level depolarizing noise, the decoder was tested on two code families with distances 11 and 12. It reduced average multiplications by 98 percent versus BP+OSD while eliminating per-node random number generation, trading only a modest increase in additions. These metrics matter because real-time quantum memory decoding must finish within the coherence window of physical qubits. The study design consists of Monte Carlo simulations at multiple physical error rates; no hardware implementation or latency benchmarks on FPGA or ASIC are provided. This leaves open whether the arithmetic savings translate to sub-microsecond wall-clock times on actual control electronics.
Sources (3)
- [1]Primary Source(https://arxiv.org/abs/2611.07144)
- [2]Supporting Source(https://arxiv.org/abs/2309.15354)
- [3]Supporting Source(https://arxiv.org/abs/2406.01703)