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Experimental boson sampling


Universal quantum computers1 promise a dramatic increase in speed over classical computers, but their full-size realization remains challenging2. However, intermediate quantum computational models3,4,5 have been proposed that are not universal but can solve problems that are believed to be classically hard. Aaronson and Arkhipov6 have shown that interference of single photons in random optical networks can solve the hard problem of sampling the bosonic output distribution. Remarkably, this computation does not require measurement-based interactions7,8 or adaptive feed-forward techniques9. Here, we demonstrate this model of computation using laser-written integrated quantum networks that were designed to implement unitary matrix transformations. We characterize the integrated devices using an in situ reconstruction method and observe three-photon interference10,11,12 that leads to the boson-sampling output distribution. Our results set a benchmark for a type of quantum computer with the potential to outperform a conventional computer through the use of only a few photons and linear-optical elements13.

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Figure 1: Non-classical interference.
Figure 2: The optical networks.
Figure 3: Experimental set-up.
Figure 4: Three-photon probabilities.


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The authors thank S. Aaronson, Č. Brukner and M. Ringbauer for discussions. The authors acknowledge support from the European Commission under projects ‘Q-ESSENCE—Quantum Interfaces, Sensors, and Communication based on Entanglement’ (no. 248095), ‘QuILMI—Quantum Integrated Light Matter Interface’ (no. 295293) and the ERA-Net CHIST-ERA project ‘QUASAR—Quantum States: Analysis and Realizations’, the German Ministry of Education and Research (Center for Innovation Competence program, grant no. 03Z1HN31), the John Templeton Foundation, the Vienna Center for Quantum Science and Technology (VCQ), the Austrian Nano-initiative ‘Nanostructures of Atomic Physics (NAP-PLATON)’ and the Austrian Science Fund (FWF) under projects ‘SFB-FoQuS—Foundations and Applications of Quantum Science’, ‘PhoQuSi—Photonic Quantum Simulators (Y585-N20)’ and the doctoral programme ‘CoQuS—Complex Quantum Systems’, the Vienna Science and Technology Fund (WWTF; under grant no. ICT12-041), and the Air Force Office of Scientific Research, Air Force Material Command, United States Air Force (grant no. FA8655-11-1-3004).

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M.T. designed and carried out the experiment, analysed data and waveguide structures, and wrote the manuscript. B.D. provided the theoretical analysis, analysed data and waveguide structures, and wrote the manuscript. R.H. designed and prepared the waveguide structures. S.N. and A.S. supervised the design and preparation of the waveguide structures. P.W. supervised the project, designed the experiment and wrote the manuscript.

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Correspondence to Max Tillmann or Philip Walther.

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The authors declare no competing financial interests.

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Tillmann, M., Dakić, B., Heilmann, R. et al. Experimental boson sampling. Nature Photon 7, 540–544 (2013).

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