Uncertain fate of fair sampling in quantum annealing

Understand

Recently, it was demonstrated both theoretically and experimentally on the D-Wave quantum annealer that transverse-field quantum annealing does not find all ground states with equal probability.

• In particular, it was proposed that more complex driver Hamiltonians beyond transverse fields might mitigate this shortcoming.
• Here, we investigate the mechanisms of (un)fair sampling in quantum annealing.
• While higher-order terms can improve the sampling for selected small problems, we present multiple counterexamples where driver Hamiltonians that go beyond transverse fields do not remove the sampling bias.