Measuring the Quality of Boson Samplers in the Sparse Regime

As quantum computational power increases, the key challenge for each platform is to demonstrate the quantum computational advantage that a given quantum device has over a classical one (‘quantum supremacy’). An essential aspect of this problem is verifying a claimed quantum advantage. Since a no-go theorem [1] forbids sample-efficient, device-independent verification for most QA platforms, the way forward is to construct a reasonable error model of a device, and measure the parameters of that model. In this work, we accomplish this for boson sampling [2], where the task is to sample from the output distribution of photons in a large linear optical network in the number basis.

We show that the level of imperfections in a boson sampler can be reconstructed from a sparse set of samples. We find the level of the various noise sources which are present in a data set from the largest boson sampler currently reported [3]. Our method combined with previous results [4] enables a test whether a given boson sampler has the required quality to demonstrate a quantum advantage.

[1] Hangleiter et al, Phys. Rev. Lett 122, 210502 (2019)
[2] Aaronson, Arkhipov, Theory Comput. 9, 143 (2013).
[3] Wang et al., Phys. Rev. Lett. 123 250503 (2019).
[4] Renema et al., Phys. Rev. Lett. 120, 220502 (2018).