Quantum computing is rapidly evolving as a novel scientific field and technology, poised to facilitate significant scientific breakthroughs. While numerous quantum algorithms and protocols were discovered in the previous century, the past decade has been particularly fruitful, yielding exciting results that underscore the advantages of quantum computation in various domains.

In 2023, we successfully held the first Shonan meeting on quantum computing (NO.198), focusing on “New Directions in Provable Quantum Advantages.” After the meeting, several exciting discoveries have been made in quantum algorithms, quantum learning, and quantum cryptography. This is a reunion meeting that focuses on the progress of recent developments in the past two years. We plan to invite leading researchers who have made pivotal contributions in this field as well as rising junior researchers. We aim to stimulate in-depth discussions and encourage creative brainstorming among researchers engaged in diverse topics. We hope that the meeting will fortify collaborations across various research communities, particularly on fostering ties between Asian and non-Asian researchers.

The meeting will primarily focus on the following three topics.

1. Quantum distributed computing

After Le Gall and Magniez (PODC 2018), Le Gall, Rosmanis and Nishimura (STACS 2019), and Izumi and Le Gall (PODC 2019) presented the first evidence of the superiority of quantum distributed algorithms, quantum distributed computing has been the subject of intensive investigations. After the our first Shonan meeting, in particular, there have been several exciting further developments (STOC 2024, TQC 2024) that showed the potential of quantum distributed algorithms in the fundamental LOCAL model. The objective of this seminar will be to both give an overview of these recent developments and further investigate the computational power of quantum distributed algorithms. A first target will be finding more examples in which quantum distributed algorithms can outperform classical distributed algorithms and especially developing new ones. A second goal will be investigating the limitations of quantum distributed computing by clarifying the relations with the more developed area of two-party quantum communication complexity. For this purpose, the seminar will invite participants with different backgrounds, in particular some experts of classical distributed algorithms interested in quantum computation and experts in quantum communication complexity interested in distributed computing.

2. Quantum learning algorithms

Recent findings suggest that quantum computers and quantum technologies could play a pivotal role in the future of machine learning. For instance, research has demonstrated that quantum computers could provide exponential advantages in learning classical objects when the inputs are encoded as quantum data, as quantum data could provide certain information that seems to be inaccessible by classical devices. Beyond learning classical objects, a more intriguing question has arisen in the past couple of years: how can we learn the properties of a quantum system? This question is arguably one of the most fundamental problems in quantum computing, which is also important for the future development of largescale quantum computers. Over the past few years, there has been a surge of progress in learning quantum systems, including shallow quantum circuits, quantum Pauli channels, quantum stabilizer states, and more(STOC 2024, PRL 2024, ITCS 2023). The research of these learning algorithms has led to several novel mathematical tools. One such tool, Pauli analysis, which is the Fourier analysis on the spaces of operators and the spaces of super-operators and serves as the quantum counterpart of the analysis of Boolean functions, has emerged in recent years as a versatile method in designing quantum learning algorithms (STOC 2024). Consequently, this field has garnered attention from researchers with diverse backgrounds. This seminar aims to elucidate fundamental concepts underlying quantum learning and provide an overview of exciting advancements and open directions in this field. We will invite researchers from different backgrounds, including computer science, mathematics, information theory, and physics, to share their insights and focus on quantum learning.

3. Quantum cryptography

This sub-topic aims to advance new findings on both quantum algorithmic advantages on post-quantum cryptography and quantum cryptographic advantages in realizing copy protection and other primitives. Since our prior meeting, there have been active developments, including a number by our participants. Two advances are particularly remarkable. One is a breakthrough result that appeared in June 2024, where for the first time a provably secure pseudorandom unitary, a long pursued object in quantum cryptography and complexity, was shown. The other is a novel way of capitalizing the quantum advantage experiments on NISQ device, turning them into new basis for constructing cryptographic primitives. In this proposed upcoming meeting, our focus will be on these two fronts: 1) pseudorandom unitaries with new properties as well as identifying more applications of pseudorandom unitaries in building cryptography and beyond; and 2) investigating the new assumptions from quantum advantage experiments both from a cryptanalysis perspective and employing them for new constructions. Some of our participants are among the main contributors on these topics (e.g., Mingnan Zhao, Penghui Yao and Fang Song have shown a new pseudorandom unitary construction based on their work presented in the prior meeting; Tomoyuki Marimae’s team has developed cryptographic assumptions based on quantum advantages), who will be invited again. We also expand our invitees to foster new interdisciplinary collaborations.