{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Tsujimoto Y"],"funding":["MEXT | Japan Society for the Promotion of Science (JSPS)"],"pagination":["8720"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC12504699"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["16(1)"],"pubmed_abstract":["In photonic quantum information processing, quantum operations using nonlinear photon-photon interactions are vital for implementing two-qubit gates and enabling faithful entanglement swapping. However, due to the weak interaction between single photons, the all-photonic realization of such quantum operations has remained out of reach so far. Herein, we demonstrate an entanglement swapping using sum-frequency generation between single photons in a χ<sup>(2)</sup>-nonlinear optical waveguide. We show that a high signal-to-noise ratio (SNR), stable sum-frequency-generation-based entanglement heralder with an ultralow-dark-count superconducting single-photon detector can satisfy the unprecedented SNR requirement indispensable for the swapping protocol. Furthermore, the system clock is enhance"],"journal":["Nature communications"],"pubmed_title":["Experimental entanglement swapping through single-photon χ&lt;sup&gt;(2)&lt;/sup&gt; nonlinearity."],"pmcid":["PMC12504699"],"funding_grant_id":["JP22K03490","JP18K13487","JP20K14393"],"pubmed_authors":["Kato G","Miki S","Tsujimoto Y","Fujiwara M","Terai H","Yabuno M","Wakui K","Kishimoto T"],"additional_accession":[]},"is_claimable":false,"name":"Experimental entanglement swapping through single-photon χ&lt;sup&gt;(2)&lt;/sup&gt; nonlinearity.","description":"In photonic quantum information processing, quantum operations using nonlinear photon-photon interactions are vital for implementing two-qubit gates and enabling faithful entanglement swapping. However, due to the weak interaction between single photons, the all-photonic realization of such quantum operations has remained out of reach so far. Herein, we demonstrate an entanglement swapping using sum-frequency generation between single photons in a χ<sup>(2)</sup>-nonlinear optical waveguide. We show that a high signal-to-noise ratio (SNR), stable sum-frequency-generation-based entanglement heralder with an ultralow-dark-count superconducting single-photon detector can satisfy the unprecedented SNR requirement indispensable for the swapping protocol. Furthermore, the system clock is enhance","dates":{"release":"2025-01-01T00:00:00Z","publication":"2025 Oct","modification":"2026-06-04T06:24:30.862Z","creation":"2026-05-06T03:13:27.248Z"},"accession":"S-EPMC12504699","cross_references":{"pubmed":["41057312"],"doi":["10.1038/s41467-025-63785-5"]}}