2021/05/18 by S. Langenfeld, Stefan Langenfeld, Philip Thomas +5 · 80 citations
Computer Science · Physics and Astronomy · #Computer network #Computer science #Encoding (memory) #Encryption #Node (physics) #Optical communication #Optics #Photon #Physics #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum information science #Quantum key distribution #Quantum mechanics #Quantum network #Quantum optics and atomic interactions #Repeater (horology) #Secure communication #Telecommunications #quant-ph
paper · pdf · doi:10.1103/physrevlett.126.230506
published in Physical Review Letters 126(23), 230506 (American Physical Society)
arxiv created 2021/05/18 · openalex publication_date 2021/06/11 · arxiv updated 2021/06/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Long-distance quantum communication requires quantum repeaters to overcome photon loss in optical fibers. Here we demonstrate a repeater node with two memory atoms in an optical cavity. Both atoms are individually and repeatedly entangled with photons that are distributed until each communication partner has independently received one of them. An atomic Bell-state measurement followed by classical communication serves to establish a key. We demonstrate scaling advantage of the key rate, increase the effective attenuation length by a factor of 2, and beat the error-rate threshold of 11% for unconditionally secure communication, the corner stones for repeater-based quantum networks.