Experimental entanglement swapping through single-photon χ(2) nonlinearity

Yoshiaki Tsujimoto (), Kentaro Wakui, Tadashi Kishimoto, Shigehito Miki, Masahiro Yabuno, Hirotaka Terai, Mikio Fujiwara and Go Kato
Additional contact information
Yoshiaki Tsujimoto: National Institute of Information and Communications Technology (NICT)
Kentaro Wakui: National Institute of Information and Communications Technology (NICT)
Tadashi Kishimoto: National Institute of Information and Communications Technology (NICT)
Shigehito Miki: National Institute of Information and Communications Technology (NICT)
Masahiro Yabuno: National Institute of Information and Communications Technology (NICT)
Hirotaka Terai: National Institute of Information and Communications Technology (NICT)
Mikio Fujiwara: National Institute of Information and Communications Technology (NICT)
Go Kato: National Institute of Information and Communications Technology (NICT)

Nature Communications, 2025, vol. 16, issue 1, 1-8

Abstract: 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(2)-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 enhanced by utilizing ultrafast telecom entangled photon-pair sources that operate in the GHz range. Our results confirm a lower bound 0.770(76) for the swapped state’s fidelity, surpassing the classical limit of 0.5 successfully. Our findings highlight the strong potential of broadband all-single-photonic nonlinear interactions for further sophistication in long-distance quantum communication and photonic quantum computation.

Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.nature.com/articles/s41467-025-63785-5 Abstract (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:natcom:v:16:y:2025:i:1:d:10.1038_s41467-025-63785-5

Ordering information: This journal article can be ordered from
https://www.nature.com/ncomms/

DOI: 10.1038/s41467-025-63785-5

Access Statistics for this article

Nature Communications is currently edited by Nathalie Le Bot, Enda Bergin and Fiona Gillespie

More articles in Nature Communications from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().