Experimental entanglement swapping through single-photon $χ^{(2)}$ nonlinearity

Fuente: arXiv
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Main Authors: Tsujimoto, Yoshiaki, Wakui, Kentaro, Kishimoto, Tadashi, Miki, Shigehito, Yabuno, Masahiro, Terai, Hirotaka, Fujiwara, Mikio, Kato, Go
Format: Preprint
Published: 2024
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author Tsujimoto, Yoshiaki
Wakui, Kentaro
Kishimoto, Tadashi
Miki, Shigehito
Yabuno, Masahiro
Terai, Hirotaka
Fujiwara, Mikio
Kato, Go
author_facet Tsujimoto, Yoshiaki
Wakui, Kentaro
Kishimoto, Tadashi
Miki, Shigehito
Yabuno, Masahiro
Terai, Hirotaka
Fujiwara, Mikio
Kato, Go
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2411_17267
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Experimental entanglement swapping through single-photon $χ^{(2)}$ nonlinearity
Tsujimoto, Yoshiaki
Wakui, Kentaro
Kishimoto, Tadashi
Miki, Shigehito
Yabuno, Masahiro
Terai, Hirotaka
Fujiwara, Mikio
Kato, Go
Quantum Physics
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.
title Experimental entanglement swapping through single-photon $χ^{(2)}$ nonlinearity
topic Quantum Physics
url https://arxiv.org/abs/2411.17267