In particular, scattershot boson sampling experimental demonstrations of quantum computational supremacy are challenged by the need to generate the same temporal and frequency spectra for a large number N of single photons, leading to a probability of success which scales down as the root of N and only if N^2 sources are used. 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 how the difference in the photonic spectral properties, instead of being a drawback to overcome in experimental realisations, can be exploited as a remarkable quantum resource. Interestingly, we demonstrate how harnessing the full multiphoton quantum information stored in the photonic spectra by frequency and time resolved correlation measurements in linear interferometers enables the characterization of multiphoton networks and states, produces a wide variety of multipartite entanglement, and further scale-up experimental demonstrations of quantum computational supremacy.
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)