High-fidelity four-photon GHZ states on chip

Mathias Pont (Corresponding author), Giacomo Corrielli (Corresponding author), Andreas Fyrillas, Iris Agresti, Gonzalo Carvacho, Nicolas Maring, Pierre Emmanuel Emeriau, Francesco Ceccarelli, Ricardo Albiero, Paulo Henrique Dias Ferreira, Niccolo Somaschi, Jean Senellart, Isabelle Sagnes, Martina Morassi, Aristide Lemaître, Pascale Senellart, Fabio Sciarrino, Marco Liscidini, Nadia Belabas (Corresponding author), Roberto Osellame (Corresponding author)

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Mutually entangled multi-photon states are at the heart of all-optical quantum technologies. While impressive progresses have been reported in the generation of such quantum light states using free space apparatus, high-fidelity high-rate on-chip entanglement generation is crucial for future scalability. In this work, we use a bright quantum-dot based single-photon source to demonstrate the high fidelity generation of 4-photon Greenberg-Horne-Zeilinger (GHZ) states with a low-loss reconfigurable glass photonic circuit. We reconstruct the density matrix of the generated states using full quantum-state tomography reaching an experimental fidelity to the target state of FGHZ4=(86.0±0.4)%, and a purity of PGHZ4=(76.3±0.6)%. The entanglement of the generated states is certified with a semi device-independent approach through the violation of a Bell-like inequality by more than 39 standard deviations. Finally, we carry out a four-partite quantum secret sharing protocol on-chip where a regulator shares with three interlocutors a sifted key with up to 1978 bits, achieving a qubit-error rate of 10.87%. These results establish that the quantum-dot technology combined with glass photonic circuitry offers a viable path for entanglement generation and distribution.
Original languageEnglish
Article number50
Number of pages7
Journalnpj Quantum Information
Issue number1
Publication statusPublished - 15 May 2024

Austrian Fields of Science 2012

  • 103021 Optics
  • 103026 Quantum optics

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