Approaching deterministic boson sampling with random input photonic occupation numbers and random injection times or colors

Multiphoton interference is at the very heart of quantum foundations and applications in quantum

sensing and information processing. In particular, boson sampling (BS) experiments and, in particular, scattershot boson sampling (SBS) schemes, have the potential to demonstrate quantum computational supremacy while only relying on multiphoton interference in linear optical interferometers. However, scalable experiments are challenged by the need to generate

the same temporal and frequency spectra for a large number N of single photons in each experimental

sample, leading to a probability of success which scales down either as the root of N (SBS) or exponentially in N (BS) if N^2 or N sources are used, respectively. Here, we employ sampling in the photonic input occupation numbers when N or more input channels are occupied to achieve for the first time a probability of success arbitrary close to one with only a linear number N of sources. We also show that quantum computational  supremacy can be achieved with input photons not only experimentally nonidentical but with random overlap in their input spectra from one sample to

another. This is possible by performing sampling correlation measurements in the photonic inner modes, time

and frequency, at both the interferometer input and output to ensure the occurrence of multiphoton

interference. This allows us to further enhance the probability to successfully generate a sample

and therefore the experimental scalability of boson sampling schemes with a number of sources only slightly larger than N. Therefore, these results

provide an exciting route toward future demonstrations of quantum computational supremacy with

scalable experimental resources.

 

References

[1] S. Laibacher and V. Tamma arXiv:1801.03832 (2018), arXiv:1706.05578 (2017)

[2] V. Tamma and S. Laibacher, Phys. Rev. Lett. 114, 243601 (2015)

[3] S. Laibacher and V. Tamma, Phys. Rev. Lett. 115, 243605 (2015)

[4] V. Tamma and S. Laibacher,  Quantum Inf. Process. 15(3), 1241-1262 (2015)