2014/07/31 by L. Aolita, C. Gogolin, M. Kliesch +1 · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1038/ncomms9498
published as Nature Comm. 6, 8498 (2015) · 8 pages + 20 pages appendix, 2 figures, results generalized to scenarios with post-selection, presentation improved
arxiv created 2015/01/09 · arxiv updated 2015/12/03
A major roadblock for large-scale photonic quantum technologies is the lack of practical reliable certification tools. We introduce an experimentally friendly - yet mathematically rigorous - certification test for experimental preparations of arbitrary m-mode pure Gaussian states, pure non-Gaussian states generated by linear-optical circuits with n-boson Fock-basis states as inputs, and states of these two classes subsequently post-selected with local measurements on ancillary modes. The protocol is efficient in m and the inverse post-selection success probability for all Gaussian states and all mentioned non-Gaussian states with constant n. We follow the mindset of an untrusted prover, who prepares the state, and a skeptic certifier, with classical computing and single-mode homodyne-detection capabilities only. No assumptions are made on the type of noise or capabilities of the prover. Our technique exploits an extremality-based fidelity bound whose estimation relies on non-Gaussian state nullifiers, which we introduce on the way as a byproduct result. The certification of many-mode photonic networks, as those used for photonic quantum simulations, boson samplers, and quantum metrology, is now within reach.