High-efficiency multiphoton boson sampling

Abstract

Boson sampling is considered as a strong candidate to demonstrate the "quantum computational supremacy" over classical computers. However, previous proof-ofprinciple experiments suffered from small photon number and low sampling rates owing to the inefficiencies of the single-photon sources and multi-port optical interferometers. Here, we develop two central components for high-performance boson sampling: robust multi-photon interferometers with 99% transmission rate, and actively demultiplexed single-photon sources from a quantum-dot-micropillar with simultaneously high efficiency, purity and indistinguishability. We implement and validate 3-, 4-, and 5-photon boson sampling, and achieve sampling rates of 4.96 kHz, 151 Hz, and 4 Hz, respectively, which are over 24,000 times faster than the previous experiments. Our architecture is feasible to be scaled up to larger number of photons and with higher rate to race against classical computers, and might provide experimental evidence against the Extended Church-Turing Thesis.

Classical boson sampling algorithms with superior performance to near-term experiments

“…Recently, improved rates have been demonstrated with quantum dot photon sources 8,33,34 . The current leading experimental demonstration, however, is still restricted to η ≈ 0.08 for n = 5, where q t ≈ 10 9 c t .…”

“…Photon statistics are governed by intractable matrix functions, which suggests that sampling from the distribution obtained by injecting photons into a linear optical network could be solved more quickly by a photonic experiment than by a classical computer. The apparently low resource requirements for large boson sampling experiments have raised expectations of a near-term demonstration of quantum supremacy by boson sampling 7,8 . Here we present classical boson sampling algorithms and theoretical analyses of prospects for scaling boson sampling experiments, showing that near-term quantum supremacy via boson sampling is unlikely.…”

“…In Wang et al 8 a number of realistic, near-term experimental improvements are suggested to reach 20-photon boson sampling. Using these projections we find that η is increased to approximately 0.35, which would be a major experimental breakthrough.…”

Generating indistinguishable photons from a quantum dot in a noisy environment

“…Two-level QD transitions can generate single photons with a high degree of indistinguishability [1][2][3][4][5][6][7][8][9][10][11][12][13], an ideal resource for implementing future quantum photonic technologies such as boson sampling [14,15] and perhaps ultimately linear optical quantum computing. Multilevel QD systems, including the biexciton → exciton → ground−state cascade and so-called spin−λ systems [16,17] can be used to generate entangled photon pairs [18][19][20][21] and spin-photon entanglement [22][23][24], respectively, which can underpin implementations of quantum repeaters and networks [25].…”

Megahertz high voltage pulse generator suitable for capacitive load

“…Owing to the ultra-fast response time, Pockels cells play critical roles in quantum information experiments, such as selecting measurement bases in quantum key distribution and quantum entanglement distribution, 1-3 arranging propagating path of pulses, 4,5 or performing Q-swishing in laser cavities. 6 For such applications, the rise/fall time and the repetition rate become key parameters for Pockels cells.…”