한국통신학회 KICS

Eighth Intensive Course on Quantum Communication and Computation

by Joonwoo Bae, KAIST, Korea 

  Currently, quantum information technology is no longer a topic of interest in the scientific community. The era of quantum information and communication technology (QICT) that directly exploits the laws of quantum mechanics for practical information processing tasks, such as efficient computation, secure communication, and quantum network communication, is becoming a reality. Mathematical problems that are considered intractable by conventional computation can be addressed and even rendered tractable using a quantum approach. For example, the problem of prime-number factorization, for which a quantum algorithm was proposed in 1994, can be solved by a quantum computer at an exponential speed, compared to its classical counterpart. 

  The industry continues to announce record-breaking improvements annually, with an increasing number of qubits available for quantum computing and long-distance quantum communication. Therefore, when quantum technologies are available and convenient, technological innovations can be seen in all computing-related disciplines. Simultaneously, we may also encounter some unexpected issues in real life, such as security threats, owing to efficient computation. Quantum information technology affects all areas of science, technology, and society in one way or another.

  In light of these considerations, two information technology research centers (ITRCs), namely ultra-secure quantum internet (USQI)-ITRC of Korea University and quantum computing for artificial intelligence (QCAI)-ITRC of Korea Advanced Institute of Science and Technology, had organized the 8th intensive summer course on the basics of quantum information and quantum computation. The course was scheduled for a week from August 28 to September 1, 2023. This intensive course targeted the audience who were particularly concerned about the currently available quantum technologies, known as noisy-intermediate-scale-quantum (NISQ). The content ranged from the very fundamental to the most practical aspects, catering to those aiming to demonstrate quantum advantages and capabilities beyond the limitations of conventional computation. The course delved into addressing pertinent questions about noisy quantum systems and envisaging applications of quantum technologies. The era of NISQ technologies could be rephrased as an opportunity to prepare for the days of ideal quantum information processing. 

  For this purpose, the intensive course invited expert speakers from the academic and industry sides. Prof. Jun Heo (Korea University) delivered lectures on the basics of quantum information, while Dr. Jeonghwan Shin (KT) talked about the basics and practical applications of quantum communication. Prof. Joonwoo Bae provided a detailed security analysis and related discussions. The course also included a non-quantum topic by Prof. Yongwoo Lee (Inha University)—post-quantum cryptography. This topic explores a higher level of computational security by considering mathematical problems with higher computational complexity. These lectures introduced code-based cryptography, lattice-based cryptography, and the Regev system. Lectures on the applications of NISQ algorithms were offered by Prof. Joongheon Kim (Korea University), who introduced the basics of quantum algorithms to NISQ algorithms, including quantum approximate optimization algorithms.

  The audience was diverse, ranging from undergraduate students eager to glimpse the future of information technologies, to graduate students and researchers keen on tracking the recent progress in quantum communication and computing. Industry and government sectors, the frontiers bridging academic interests to real-world quantum applications, were also represented among the attendees. Questions, comments, and answers were observed during the five-day lectures. Interactions among instructors and audience fostered the generation of novel ideas, the exploration of new directions, and a deeper understanding of QICT. The 8th intensive course was the most successful, boasting the largest audience and most active interactions compared to the past. These tell why the Korean Institute of Communications and Information Sciences (KICS) should continue intensive courses in quantum technologies.

  Finally, important key results were obtained for 2023. Regev devised a polynomial speedup over the Shor algorithm, and an improvement was made after approximately 30 years. Device-independent quantum key distribution protocols were realized, achieving the highest level of security without relying on computational assumptions or implementation details, but solely on the quantum nature of the working principles. Beyond two-party communication, network information theory may also show quantum advantages in scenarios such as multiple access and interference channels. 

  From the perspective of national quantum activities, the week of the intensive course (August 28 to September 1) was rich in various quantum meetings in Korea, such as the Asian Quantum Information Science, which is the world's largest conference on advances in quantum information, and Photonics Meeting of the Optics Society of Korea in Jeju. QICT, which is becoming closer to industrial applications, will attract more people from various fields.