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Cheng J, Liang S, Qin J, Li J, Zeng B, Shi Y, Yan Z, Jia X. Quantum randomness introduced through squeezing operations and random number generation. OPTICS EXPRESS 2024; 32:18237-18246. [PMID: 38858985 DOI: 10.1364/oe.520041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 04/22/2024] [Indexed: 06/12/2024]
Abstract
Quantum random numbers play a crucial role in diverse applications, including cryptography, simulation, and artificial intelligence. In contrast to predictable algorithm-based pseudo-random numbers, quantum physics provides new avenues for generating theoretically true random numbers by exploiting the inherent uncertainty contained in quantum phenomena. Here, we propose and demonstrate a quantum random number generator (QRNG) using a prepared broadband squeezed state of light, where the randomness of the generated numbers entirely originates from the quantum noise introduced by squeezing operation rather than vacuum noise. The relationship between entropy rate and squeezing level is analyzed. Furthermore, we employ a source-independent quantum random number protocol to enhance the security of the random number generator.
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Zeng H, He ZQ, Fan YR, Luo Y, Lyu C, Wu JP, Li YB, Liu S, Wang D, Zhang DC, Zeng JJ, Deng GW, Wang Y, Song HZ, Wang Z, You LX, Guo K, Sun CZ, Luo Y, Guo GC, Zhou Q. Quantum Light Generation Based on GaN Microring toward Fully On-Chip Source. PHYSICAL REVIEW LETTERS 2024; 132:133603. [PMID: 38613308 DOI: 10.1103/physrevlett.132.133603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/12/2023] [Accepted: 01/29/2024] [Indexed: 04/14/2024]
Abstract
An integrated quantum light source is increasingly desirable in large-scale quantum information processing. Despite recent remarkable advances, a new material platform is constantly being explored for the fully on-chip integration of quantum light generation, active and passive manipulation, and detection. Here, for the first time, we demonstrate a gallium nitride (GaN) microring based quantum light generation in the telecom C-band, which has potential toward the monolithic integration of quantum light source. In our demonstration, the GaN microring has a free spectral range of 330 GHz and a near-zero anomalous dispersion region of over 100 nm. The generation of energy-time entangled photon pair is demonstrated with a typical raw two-photon interference visibility of 95.5±6.5%, which is further configured to generate a heralded single photon with a typical heralded second-order autocorrelation g_{H}^{(2)}(0) of 0.045±0.001. Our results pave the way for developing a chip-scale quantum photonic circuit.
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Affiliation(s)
- Hong Zeng
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
- Key Laboratory of Quantum Physics and Photonic Quantum Information, Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Zhao-Qin He
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
| | - Yun-Ru Fan
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
- Key Laboratory of Quantum Physics and Photonic Quantum Information, Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yue Luo
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Chen Lyu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Jin-Peng Wu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
- Key Laboratory of Quantum Physics and Photonic Quantum Information, Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yun-Bo Li
- Department of Fundamental Network Technology, China Mobile Research Institute, Beijing 100053, China
| | - Sheng Liu
- Department of Fundamental Network Technology, China Mobile Research Institute, Beijing 100053, China
| | - Dong Wang
- Department of Fundamental Network Technology, China Mobile Research Institute, Beijing 100053, China
| | - De-Chao Zhang
- Department of Fundamental Network Technology, China Mobile Research Institute, Beijing 100053, China
| | - Juan-Juan Zeng
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
- Center for Quantum Internet, Tianfu Jiangxi Laboratory, Chengdu 641419, China
| | - Guang-Wei Deng
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
- Key Laboratory of Quantum Physics and Photonic Quantum Information, Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - You Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
- Southwest Institute of Technical Physics, Chengdu 610041, China
| | - Hai-Zhi Song
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
- Southwest Institute of Technical Physics, Chengdu 610041, China
| | - Zhen Wang
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Li-Xing You
- National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Kai Guo
- Institute of Systems Engineering, AMS, Beijing 100141, China
| | - Chang-Zheng Sun
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
| | - Yi Luo
- Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
| | - Guang-Can Guo
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
- Key Laboratory of Quantum Physics and Photonic Quantum Information, Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
- Center for Quantum Internet, Tianfu Jiangxi Laboratory, Chengdu 641419, China
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
| | - Qiang Zhou
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China
- Key Laboratory of Quantum Physics and Photonic Quantum Information, Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
- Center for Quantum Internet, Tianfu Jiangxi Laboratory, Chengdu 641419, China
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
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Wei Y, Liu S, Li X, Yu Y, Su X, Li S, Shang X, Liu H, Hao H, Ni H, Yu S, Niu Z, Iles-Smith J, Liu J, Wang X. Tailoring solid-state single-photon sources with stimulated emissions. NATURE NANOTECHNOLOGY 2022; 17:470-476. [PMID: 35410369 DOI: 10.1038/s41565-022-01092-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 02/15/2022] [Indexed: 06/14/2023]
Abstract
The coherent interaction of electromagnetic fields with solid-state two-level systems can yield deterministic quantum light sources for photonic quantum technologies. To date, the performance of semiconductor single-photon sources based on three-level systems is limited mainly due to a lack of high photon indistinguishability. Here we tailor the cavity-enhanced spontaneous emission from a ladder-type three-level system in a single epitaxial quantum dot through stimulated emission. After populating the biexciton (XX) of the quantum dot through two-photon resonant excitation, we use another laser pulse to selectively depopulate the XX state into an exciton (X) state with a predefined polarization. The stimulated XX-X emission modifies the X decay dynamics and improves the characteristics of a polarized single-photon source, such as a source brightness of 0.030(2), a single-photon purity of 0.998(1) and an indistinguishability of 0.926(4). Our method can be readily applied to existing quantum dot single-photon sources and expands the capabilities of three-level systems for advanced quantum photonic functionalities.
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Affiliation(s)
- Yuming Wei
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China
| | - Shunfa Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China
| | - Xueshi Li
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China
| | - Ying Yu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China
| | - Xiangbin Su
- State Key Laboratory for Superlattice and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Shulun Li
- State Key Laboratory for Superlattice and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Xiangjun Shang
- State Key Laboratory for Superlattice and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Hanqing Liu
- State Key Laboratory for Superlattice and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Huiming Hao
- State Key Laboratory for Superlattice and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Haiqiao Ni
- State Key Laboratory for Superlattice and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Siyuan Yu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China
| | - Zhichuan Niu
- State Key Laboratory for Superlattice and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Jake Iles-Smith
- Department of Physics and Astronomy, The University of Manchester, Manchester, UK
- Department of Electrical and Electronic Engineering, The University of Manchester, Manchester, UK
| | - Jin Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China.
| | - Xuehua Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China
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Wan Y, Chen K, Huang F, Wang P, Leng X, Li D, Kang J, Qiu Z, Yao Y. A flexible and stretchable bionic true random number generator. NANO RESEARCH 2022; 15:4448-4456. [PMID: 35281218 PMCID: PMC8902273 DOI: 10.1007/s12274-022-4109-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/20/2021] [Accepted: 12/24/2021] [Indexed: 05/11/2023]
Abstract
UNLABELLED The volume of securely encrypted data transmission increases continuously in modern society with all things connected. Towards this end, true random numbers generated from physical sources are highly required for guaranteeing security of encryption and decryption schemes for exchanging sensitive information. However, majority of true random number generators (TRNGs) are mechanically rigid, and thus cannot be compatibly integrated with some specific flexible platforms. Herein, we present a flexible and stretchable bionic TRNG inspired by the uniqueness and randomness of biological architectures. The flexible TRNG film is molded from the surface microstructures of natural plants (e.g., ginkgo leaf) via a simple, low-cost, and environmentally friendly manufacturing process. In our proof-of-principle experiment, the TRNG exhibits a fast generation speed of up to 1.04 Gbit/s, in which random numbers are fully extracted from laser speckle patterns with a high extraction rate of 72%. Significantly, the resulting random bit streams successfully pass all randomness test suites including NIST, TestU01, and DIEHARDER. Even after 10,000 times cyclic stretching or bending tests, or during temperature shock (-25-80 °C), the bionic TRNG still reveals robust mechanical reliability and thermal stability. Such a flexible TRNG shows a promising potential in information security of emerging flexible networked electronics. ELECTRONIC SUPPLEMENTARY MATERIAL Supplementary material (light path diagram of transmitted laser speckle, pseudo random pattern, statistical distribution of bionic microstructures, haze of the bionic TRNG film, multi-layer circular laser intensity pattern, percentage of bit 0/1 for different hashed images, Pearson correlation coefficient between 100 different speckle images, the whole process of randomness extraction, SEM images of the flexible TRNG film after 10,000 times stretching and bending, continuous work stability of the TRNG at low or high temperature, light path diagram of reflective laser speckle, and detailed randomness test results of NIST, TestU01, and DIEHARDER) is available in the online version of this article at 10.1007/s12274-022-4109-9.
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Affiliation(s)
- Yongbiao Wan
- Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, 610200 China
- Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, 621999 China
| | - Kun Chen
- Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, 610200 China
- Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, 621999 China
| | - Feng Huang
- Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, 610200 China
- Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, 621999 China
| | - Pidong Wang
- Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, 610200 China
- Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, 621999 China
| | - Xiao Leng
- Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, 610200 China
- Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, 621999 China
| | - Dong Li
- Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, 610200 China
- Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, 621999 China
| | - Jianbin Kang
- Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, 610200 China
- Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, 621999 China
| | - Zhiguang Qiu
- School of Electronics and Information Technology, State Key Lab of Opto-Electronic Materials & Technologies, Guangdong Province Key Lab of Display Materials and Technologies, Sun Yat-sen University, Guangzhou, 510275 China
| | - Yao Yao
- Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, 610200 China
- Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, 621999 China
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Chen K, Huang F, Wang P, Wan Y, Li D, Yao Y. Fast random number generator based on optical physical unclonable functions. OPTICS LETTERS 2021; 46:4875-4878. [PMID: 34598222 DOI: 10.1364/ol.435221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/29/2021] [Indexed: 05/25/2023]
Abstract
We propose an approach for fast random number generation based on homemade optical physical unclonable functions (PUFs). The optical PUF is illuminated with input laser wavefront of continuous modulation to obtain different speckle patterns. Random numbers are fully extracted from speckle patterns through a simple post-processing algorithm. Our proof-of-principle experiment achieves total random number generation rate of 0.96 Gbit/s with verified randomness, which is far faster than previous optical-PUF-based schemes. Our results demonstrate that the presented random number generator (RNG) proposal has great potential to achieve ultrafast random number generation rate up to several hundreds of Gbit/s.
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Hsu BW, Chuang YT, Cheng CY, Chen CY, Chen YJ, Brumberg A, Yang L, Huang YS, Schaller RD, Chen LJ, Chuu CS, Lin HW. Very Robust Spray-Synthesized CsPbI 3 Quantum Emitters with Ultrahigh Room-Temperature Cavity-Free Brightness and Self-Healing Ability. ACS NANO 2021; 15:11358-11368. [PMID: 33729770 DOI: 10.1021/acsnano.1c00733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Although colloidal lead halide perovskite quantum dots (PQDs) exhibit desirable emitter characteristics with high quantum yields and narrow bandwidths, instability has limited their applications in devices. In this paper, we describe spray-synthesized CsPbI3 PQD quantum emitters displaying strong photon antibunching and high brightness at room temperature and stable performance under continuous excitation with a high-intensity laser for more than 24 h. Our PQDs provided high single-photon emission rates, exceeding 9 × 106 count/s, after excluding multiexciton emissions and strong photon antibunching, as confirmed by low values of the second-order correlation function g(2)(0) (reaching 0.021 and 0.061 for the best and average PQD performance, respectively). With such high brightness and stability, we applied our PQDs as quantum random number generators, which demonstrably passed all of the National Institute of Standards and Technology's randomness tests. Intriguingly, all of the PQDs exhibited self-healing behavior and restored their PL intensities to greater than half of their initial values after excitation at extremely high intensity. Half of the PQDs even recovered almost all of their initial PL intensity. The robust properties of these spray-synthesized PQDs resulted from high crystallinity and good ligand encapsulation. Our results suggest that spray-synthesized PQDs have great potential for use in future quantum technologies (e.g., quantum communication, quantum cryptography, and quantum computing).
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Affiliation(s)
- Bo-Wei Hsu
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yung-Tang Chuang
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chun-Yuan Cheng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Center for Quantum Technology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chien-Yu Chen
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208 United States
| | - Yen-Ju Chen
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Center for Quantum Technology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Alexandra Brumberg
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208 United States
| | - Lin Yang
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yu-Sheng Huang
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Richard D Schaller
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208 United States
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439 United States
| | - Lih-J Chen
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chih-Sung Chuu
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Center for Quantum Technology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Hao-Wu Lin
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
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Hu YY, Ding YY, Wang S, Yin ZQ, Chen W, He DY, Huang W, Xu BJ, Guo GC, Han ZF. Compact quantum random number generation using a linear optocoupler. OPTICS LETTERS 2021; 46:3175-3178. [PMID: 34197409 DOI: 10.1364/ol.430043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/02/2021] [Indexed: 06/13/2023]
Abstract
To date, various quantum random number schemes have been demonstrated. However, the cost, size, and final random bit generation rate usually limits their wide application on-shelf. To overcome these limitations, we propose and demonstrate a compact, simple, and low-cost quantum random number generation based on a linear optocoupler. Its integrated structure consists mainly of a light emitting diode and a photodetector. Random bits are generated by directly measuring the intensity noise of the output light, which originates from the random recombination between holes of the p region and electrons of the n region in a light emitting diode. Moreover, our system is robust against fluctuation of the operating environment, and can be extended to a parallel structure, which will be of great significance for the practical and commercial application of quantum random number generation. After post-processing by the SHA-256 algorithm, a random number generation rate of 43 Mbps is obtained. Finally, the final random bit sequences have low autocorrelation coefficients with a standard deviation of 3.16×10-4 and pass the NIST-Statistical Test Suite test.
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Lim K, Choi BS, Baek JH, Kim M, Choe JS, Kim KJ, Ko YH, Youn CJ. Countermeasure for security loophole caused by asymmetric correlations of reference frame independent quantum key distribution with fewer quantum states. OPTICS EXPRESS 2021; 29:18966-18975. [PMID: 34154140 DOI: 10.1364/oe.427055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/25/2021] [Indexed: 06/13/2023]
Abstract
One of the challenging issues in free-space quantum key distribution (QKD) is the requirement of active compensation of the reference frame between the transmitter and receiver. Reference frame independent (RFI) QKD removes active compensation, but it requires more quantum states. A recent proposal can effectively reduce the required quantum states, but this can be achieved assuming the correlations defined in RFI QKD are symmetric. In a real QKD system, such symmetric correlations cannot always be satisfied owing to the device imperfections and optical misalignment. We theoretically analyze the effect of asymmetric correlations. Consequently, we report that the asymmetry causes security loopholes and provide a countermeasure to prevent them. Furthermore, we provide the experimental results of a free-space RFI QKD system to verify the countermeasure for the aforementioned problem. In conclusion, our work provides feasibility of the practical RFI QKD system with fewer quantum states by effectively preventing the security loophole.
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