Broadcast continuous variable quantum key distribution

• Project/Area Number: 18H01157
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: National Institute of Information and Communications Technology
• Principal Investigator: Takeoka Masahiro 国立研究開発法人情報通信研究機構, 未来ICT研究所量子ICT先端開発センター, センター長 (70415850)
• Co-Investigator(Kenkyū-buntansha): 平野 琢也 学習院大学, 理学部, 教授 (00251330)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥17,680,000 (Direct Cost: ¥13,600,000、Indirect Cost: ¥4,080,000); Fiscal Year 2020: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000); Fiscal Year 2019: ¥5,720,000 (Direct Cost: ¥4,400,000、Indirect Cost: ¥1,320,000); Fiscal Year 2018: ¥9,750,000 (Direct Cost: ¥7,500,000、Indirect Cost: ¥2,250,000)
• Keywords: 連続量量子鍵配送 / ブロードキャスト通信路 / 波長多重量子鍵配送 / 量子暗号 / ネットワーク通信路

Outline of Final Research Achievements

We propose a novel network-type quantum key distribution (QKD) where one sender and multiple receivers are connected via a broadcast channel and the total key rate can be increased by collaborative operation among the sender and the receivers. We implement this “broadcast-QKD” in the lab and performed its proof-of-principle experiment. We also pursued more general framework and technologies for the network based QKD and related quantum security protocols. We derive key rate increases of the continuous variable QKD (CVQKD) under the limited attack by eavesdroppers and also develop and demonstrate the wavelength multiplexing of CVQKDs and ultrahigh-speed optical communication.

Academic Significance and Societal Importance of the Research Achievements

ブロードキャスト型QKDは本研究グループ独自の理論に基づく方式であり、その実装にいち早く取り組み原理実証を行ったことは学術的に高い意義があると考える。また、本方式がベースとしている１対１の連続量量子鍵配送（CVQKD）方式そのものは、近い将来の実用化が期待されるQKD方式であるが、実用上重要となる光通信との波長多重化や、QKD自身の波長多重化の設計と原理実証に成功したことは社会的に高い意義があると考える。

Research Products

• [Int'l Joint Research] デンマーク工科大学(デンマーク)
• [Int'l Joint Research] ルイジアナ州立大学(米国)
• [Journal Article] Limit of Gaussian operations and measurements for Gaussian state discrimination and its application to state comparison (2021)
  • Author(s): Roberson David E.、Izumi Shuro、Roga Wojciech、Neergaard-Nielsen Jonas S.、Takeoka Masahiro、Andersen Ulrik L.
  • Journal Title: Physical Review A Volume: 103 Issue: 2
  • DOI: 10.1103/physreva.103.022423
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Wavelength division multiplexing of 194 continuous variable quantum key distribution channels (2020)
  • Author(s): Tobias A. Eriksson, Ruben S. Luis, Benjamin J. Puttnam, Georg Rademacher, Mikio Fujiwara, Yoshinari Awaji, Hideaki Furukawa, Naoya Wada, Masahiro Takeoka, and Masahide Sasaki
  • Journal Title: Journal of Lightwave Technology Volume: -
  • Peer Reviewed / Open Access
• [Journal Article] Crosstalk Impact on Continuous Variable Quantum Key Distribution in Multicore Fiber Transmission (2019)
  • Author(s): Eriksson Tobias A.、Puttnam Benjamin J.、Rademacher Georg、Luis Ruben S.、Fujiwara Mikio、Takeoka Masahiro、Awaji Yoshinari、Sasaki Masahide、Wada Naoya
  • Journal Title: IEEE Photonics Technology Letters Volume: 31 Issue: 6 Pages: 467-470
  • DOI: 10.1109/lpt.2019.2898458
  • Peer Reviewed
• [Journal Article] Wavelength division multiplexing of continuous variable quantum key distribution and 18.3 Tbit/s data channels (2019)
  • Author(s): Eriksson Tobias A.、Hirano Takuya、Puttnam Benjamin J.、Rademacher Georg、Lu?s Ruben S.、Fujiwara Mikio、Namiki Ryo、Awaji Yoshinari、Takeoka Masahiro、Wada Naoya、Sasaki Masahide
  • Journal Title: Communications Physics Volume: 2 Issue: 1 Pages: 9-9
  • DOI: 10.1038/s42005-018-0105-5
  • Peer Reviewed / Open Access
• [Journal Article] Secret key rates for intensity-modulated dual-threshold detection key distribution under individual beam splitting attacks (2018)
  • Author(s): Eriksson Tobias A.、Trinh Phuc V.、Endo Hiroyuki、Takeoka Masahiro、Sasaki Masahide
  • Journal Title: Optics Express Volume: 26 Issue: 16 Pages: 20409-20409
  • DOI: 10.1364/oe.26.020409
  • Peer Reviewed / Open Access
• [Journal Article] Secret key rate of a continuous-variable quantum-key-distribution scheme when the detection process is inaccessible to eavesdroppers (2018)
  • Author(s): Namiki Ryo、Kitagawa Akira、Hirano Takuya
  • Journal Title: Physical Review A Volume: 98 Issue: 4 Pages: 042319-042319
  • DOI: 10.1103/physreva.98.042319
  • Peer Reviewed
• [Presentation] Multipartite entanglement and secret key distribution in quantum networks (2020)
  • Author(s): Eneet Kaur, Masahiro Takeoka, Mark M. Wilde, and Wojciech Roga
  • Organizer: 22nd Annual Southwest Quantum Information and Technology Workshop (SQuinT)
  • Int'l Joint Research
• [Presentation] 量子ネットワークの量子通信路容量について (2020)
  • Author(s): 武岡 正裕
  • Organizer: 電子情報通信学会2020年総合大会
  • Invited
• [Presentation] Continuous variable quantum key distribution multiplexed with high throughput coherent channels (2019)
  • Author(s): Tobias Eriksson, Takuya Hirano, Benjamin Puttnam, Georg Rademacher, Ruben Luis, Mikio Fujiwara, Ryo Namiki, Yoshinari Awaji, Masahiro Takeoka, Naoya Wada and Masahide Sasaki
  • Organizer: 9th International Conference on Quantum Cryptography (QCrypt 2019)
  • Int'l Joint Research
• [Presentation] Continuous operation of four-states continuous-variable quantum key distribution system (2019)
  • Author(s): Takuya Hirano and Ryo Namiki
  • Organizer: 日米欧量子科学技術国際シンポジウム
  • Int'l Joint Research
• [Presentation] Coexistence of Continuous Variable Quantum Key Distribution and 7 × 12.5 Gbit/s Classical Channels (2018)
  • Author(s): Tobias Eriksson, Takuya Hirano, Motoharu Ono, Mikio Fujiwara, Ryo Namiki, Ken-ichiro Yoshino, Akio Tajima, Masahiro Takeoka and Masahide Sasaki,
  • Organizer: IEEE Summer Topicals Meeting Series
  • Int'l Joint Research
• [Presentation] Time-Domain Measurement of Continuous-Variable Entanglement Using Temporally Shaped Local Oscillator Pulses (2018)
  • Author(s): Ami Shinjjo, Yujiro Eto,and Takuya Hirano
  • Organizer: IEEE Summer Topicals Meeting Series
  • Int'l Joint Research
• [Presentation] Continuous Variable Quantum Key Distribution Multiplexed with Classical Channels (2018)
  • Author(s): Tobias Eriksson, Takuya Hirano, Georg Rademacher, Benjamin Puttnam, Ruben Luis, Mikio Fujiwara, Ryo Namiki, Ken-Ichiro Yoshino, Akio Tajima, Yoshinari Awaji, Masahiro Takeoka, Naoya Wada and Masahide Sasaki
  • Organizer: 8th International Conference on Quantum Cryptography
  • Int'l Joint Research
• [Presentation] Joint Propagation of Continuous Variable Quantum Key Distribution and18×24.5Gbaud PM-16QAM Channels (2018)
  • Author(s): Tobias A. Eriksson, Takuya Hirano, Georg Rademacher, Benjamin J. Puttnam, Ruben S. Luis, Mikio Fujiwara, Ryo Namiki, Yoshinari Awaji, Masahiro Takeoka, Naoya Wada and Masahide Sasaki
  • Organizer: 2018 European Conference on Optical Communication (ECOC)
  • Int'l Joint Research
• [Presentation] 時間幅の短い局部発振光を用いたパルス光連続変数エンタングルメントの時間領域測定II (2018)
  • Author(s): 新城亜美, 片山拓哉, 衞藤雄二郎, 平野琢也
  • Organizer: 日本物理学会 2018年 秋季大会
• [Presentation] Pulse-resolved measurement of continuous-variable EPR entanglement with shaped local oscillators (2018)
  • Author(s): Ami Shinjo、Takuya Katayama、Yujiro Eto、Takuya Hirano
  • Organizer: 第79回 応用物理学会 秋季学術講演会
• [Presentation] Two instances of majorization relations for two-mode squeezed number states (2018)
  • Author(s): Ryo Namiki
  • Organizer: 第39回量子情報技術研究会（QIT39）
• [Presentation] 波形整形した局部発振光を用いたパルス光連続変数エンタングルメントの時間領域測定 (2018)
  • Author(s): 新城 亜美, 片山 拓哉, 衞藤 雄二郎, 平野 琢也
  • Organizer: 第66回応用物理学会 春季学術講演会