Boson Sampling with 20 Input Photons and a 60-Mode Interferometer in a1014-Dimensional Hilbert Space

Abstract

Quantum computing experiments are moving into a new realm of increasing size and complexity, with the short-term goal of demonstrating an advantage over classical computers. Boson sampling is a promising platform for such a goal, however, the number of involved single photons was up to five so far, limiting these small-scale implementations to a proof-of-principle stage. Here, we develop solidstate sources of highly efficient, pure and indistinguishable single photons, and 3D integration of ultra-low-loss optical circuits. We perform an experiment with 20 single photons fed into a 60-mode interferometer, and, in its output, sample over Hilbert spaces with a size of 10 14 -over ten orders of magnitude larger than all previous experiments. The results are validated against distinguishable samplers and uniform samplers with a confidence level of 99.9%.

Quantum experiments and hypergraphs: Multiphoton sources for quantum interference, quantum computation, and quantum entanglement

“…We have shown that one can investigate the striking properties of hypergraphs by implementing quantum experiments in laboratories. For example, classically intractable decision problems of perfect matchings in hypergraphs can be solved by experimentally detecting an N -fold coincidences case, indicating a potential advantage of quantum experiments and further related to quantum computational supremacy [76,81,83]. Our connection may enable future applications in quantum computation, especially in connection to already existing algorithms employing hypergraphs, e.g., the 3-SAT problem [96].…”

“…It points toward the possibility of classically intractable problems that can be answered using quantum re-sources. This difficulty is related to, but conceptually simpler than Boson Sampling [68][69][70][71][72][73][74][75][76]. Boson Sampling exploits the fact that counting all perfect matchings is difficult classically (which is in #P-complete complexity class [77]), and obtains related properties using sampling techniques.…”

Experimental quantification of four-photon indistinguishability

“…Recent proposals use twophoton interference for the realization of two-qubit gates, essential elements for photon-based quantum computing schemes [6]. Multiphoton interference is at the core of the computational complexity of linear optical networks, as exemplified by the Boson Sampling problem [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. This problem, solved naturally by multiphoton interference, shows that simulating the dynamics of indistinguishable photons is likely to be hard for classical computers, which also suggests that certification of genuine multiphoton interference is a difficult problem [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

“…In particular, the special design of the interferometer allows to perform the experiment with a parametric down-conversion source without the need for heralding. This represents a demonstration of a practical approach to the characterization of multiphoton sources, which promises to decrease the experimental effort required to benchmark future deterministic single-photon sources [49][50][51] in the regime of high number of photons [16][17][18][19]25].…”

Sample caching Markov chain Monte Carlo approach to boson sampling simulation

“…On the other hand, its classical simulation involves computing permanents of Gaussian complex matrices [6], which is likely to be classically intractable, even in approximation cases [7]. The classical hardness of boson sampling attracts enormous efforts to build large-scale physical devices to beat classical computers, and remarkable achievements have been made [8][9][10][11][12][13][14][15][16][17][18]. It is promising to show quantum advantage via boson sampling.…”