  A boson sampling device could efficiently sample from the output probability
distribution of noninteracting bosons undergoing many-body interference. This
problem is not only classically intractable, but its solution is also believed
to be classically unverifiable. Hence, a major difficulty in experiment is to
ensure a boson sampling device performs correctly. We present an experimental
friendly scheme to extract useful and robust information from the quantum boson
samplers based on coarse-grained measurements. The procedure can be applied to
certify the equivalence of boson sampling devices while ruling out alternative
fraudulent devices. We perform numerical simulations to demonstrate the
feasibility of the method and consider the effects of realistic noise. Our
approach is expected to be generally applicable to other many-body
certification tasks beyond the boson sampling problem.
