ICEPP-QUP Quantum Workshop 2026

18 May 2026, 10:00 → 19 May 2026, 18:00 Asia/Tokyo

Koshiba Hall, The University of Tokyo

Koji Terashi (University of Tokyo (JP)), Masaya Ishino (University of Tokyo (JP)), Tatsumi Nitta (KEK), Toshiyuki Azuma (KEK)

Short URL: https://indico.global/e/IQWS2026

Over the past decade, quantum technologies have progressed at an extraordinary pace. Advances in quantum computing and quantum sensing, together with the development of fundamental quantum algorithms and a growing range of quantum applications, have brought the realization of quantum advantage increasingly close.

Building on this momentum, this workshop aims to provide a forum for discussing the current state and future directions of quantum technologies. The workshop is organized around quantum theory, quantum computation, and quantum sensing as central themes, while exploring their experimental and theoretical applications across diverse areas such as particle physics, cosmology, and nuclear physics.

By bringing together researchers from different communities and highlighting forward-looking ideas as well as state-of-the-art quantum technologies and computational techniques, the workshop seeks to foster discussions on new opportunities, including novel quantum error-correction strategies, applications to fault-tolerant quantum computing, and advanced quantum sensing enabled by cutting-edge quantum algorithms.

Invited Speakers :

• Yutaro Iiyama (ICEPP, UTokyo)
• Yoshiro Takahashi (Kyoto U.)
• Takaaki Takenaka (NTT)
• Shion Chen (Kyoto U.)
• Tatsumi Nitta (KEK QUP)
• Atsushi Noguchi (UTokyo)
• Keisuke Fujii (Kyoto U.)
• Masazumi Honda (RIKEN)
• Seiji Yunoki (RIKEN)
• Nobuyuki Yoshioka (ICEPP, UTokyo)

(Japanese alphabetical order)

 Those who want to present talk or poster are asked to submit via the “Call for Abstracts” page (submission is closed).

Participation registration is open now. The registration is closed.

Note: We plan to organize this workshop in a "mixed" language mode, i.e, the presentation slides will be prepared in English, while the oral talk and discussion will be given in Japanese.

Monday 18 May

10:00 → 12:30 Session 1

Convener: Koji Terashi (University of Tokyo (JP))

10:00 Introduction

Speaker: Toshiyuki Azuma (KEK)

10:05 New physics search using ultracold atoms

In this talk, I will report our recent experiments of precision measurement for new physics beyond the Standard Model. Owing to the existence of ultranarrow optical transitions between the ground and metastable states and many isotopes we search for a new hypothetical particle mediating a force between an electron and a neutron, through precision isotope-shift measurements using ultracold bosonic Yb atoms in a magic-wavelength lattice. Implications of the results on some specific models of elementary particle theory as well as nuclear physics are also mentioned. In addition, we only briefly report on our progress towards quantum computing using Yb atom tweezer array.

Speaker: Yoshiro Takahashi (Kyoto University)

10:50 Dark Matter Search with a Superconducting Quantum Processor

A system of transmon qubits is proposed as a potential platform to detect dark matter (DM) [1]. The sensitivity of the detector was shown to be enhanced by entangling a large number of qubits under the assumption that the hidden photon associated with the DM acts equally on all qubits as the same unitary operator $U_\mathrm{DM}$. We call this signal collective noise.

Qubits can be protected from collective noise by the so-called noiseless subsystem [2]. Consider a system of 3 qubits. Using the permutation symmetry of collective noise, it can be shown that there is a unitary transformation $U_E \in U(2^3)$, such that [2]
$$ U_E^\dagger (U_\mathrm{DM}^{\otimes 3})U_E|0\rangle |\phi\rangle| \psi\rangle = |0\rangle |\phi\rangle U_\mathrm{DM}|\psi\rangle. $$ $|\phi\rangle$ is immune to noise under this error-avoiding encoding. We take $|\phi\rangle=|0\rangle$ and $|\psi \rangle \in {|0\rangle, |+\rangle, |y+\rangle}$ in the following. [1] showed that the sensitivity of the proposed detector is $\propto n_q^2 \delta^2$, where $n_q$ is the number of qubits that participate in the entanglement and $\delta=\eta \tau$ is a small parameter where $\eta$ is a coupling parameter between hidden photon DM and transmons and $\tau$ is the integration time in detector. In this new proposal, deviation of the measurement outcome from the no-noise case is proportional to $\sin \delta\sim \delta$, although the sensitivity enhancement factor may not be literally $\sim 1/\delta$ if the standard quantum limit is taken into account, for example. The output state $|00\rangle$ of the first two qubits signals that the noise is collective. In our talk, we will introduce the quantum circuit implementing $U_E$ and propose a QPU design that can be fabricated within near-future technology. $[1]$ Chen, Shion and Fukuda, Hajime and Inada, Toshiaki and Moroi, Takeo and Nitta, Tatsumi and Sichanugrist, Thanaporn, Phys. Rev. D **110**, 115021 (2024) $[2]$ G\"ung\"ord\"u, Utkan and Li, Chi-Kwong and Nakahara, Mikio and Poon, Yiu-Tung and Sze, Nung-Sing, Phys. Rev. A 89, 042301 (2014)

Speaker: Mikio Nakahara (IQM Quantum Computers)

11:15 Break

11:45 Toward Practical Quantum Advantage on Early Fault-Tolerant Quantum Computers

We present a perspective on achieving practical quantum advantage in the era of early fault-tolerant quantum computers (early FTQC). We begin with a brief overview of recent progress in quantum error correction, which has demonstrated initial error suppression but remains far from large-scale fault tolerance, and then identify the central bottlenecks for early FTQC, including the substantial space–time overhead of error correction, the cost of non-Clifford operations, and limitations in decoding and control. To address these challenges, we introduce our group’s recent advances in architecture, compilation, and error correction, including methods for reducing T-count, enabling efficient logical analog rotations, and developing scalable low-overhead decoding strategies. Finally, we present resource estimates for scientifically and industrially relevant applications, highlighting regimes in which early FTQC devices with realistic physical error rates and qubit counts may achieve meaningful computational advantage.

Speaker: Keisuke Fujii (Kyoto University)

12:30 → 14:00 Lunch

14:00 → 16:25 Session 2

Convener: Ryu Sawada (University of Tokyo (JP))

14:00 Exploring Many-Body Physics with Quantum Computers: Quantum Dynamics and Quantum-HPC Hybrid Computation

Quantum computers are opening new opportunities for exploring quantum many-body systems, both as programmable platforms for studying nonequilibrium dynamics and as computational tools within hybrid quantum-classical workflows. In this talk, I will present recent progress in these two directions, focusing first on quantum dynamics experiments on digital quantum processors [1-4] and then on hybrid quantum-HPC computation for many-body physics and chemistry [5-7].

I will begin with recent experiments on nonequilibrium quantum dynamics in programmable superconducting-qubit systems, including Floquet many-body dynamics in regimes that are difficult to access with classical simulations alone. These studies demonstrate that present-day quantum processors can already serve as valuable experimental platforms for exploring complex many-body phenomena, especially when combined with classical verification methods such as tensor-network simulations.

I will then discuss quantum-classical hybrid computation that integrate quantum hardware with high-performance classical computing to address problems beyond the reach of conventional exact diagonalization. Representative examples include selected configuration interaction approaches for ground-state calculations, as well as quantum-enhanced tensor-network approaches. Enabled by close integration between on-premise quantum processors and large-scale supercomputers such as Fugaku, these approaches illustrate how hybrid architectures can extend the frontier of practically tractable computation.

These developments point to a new regime of quantum computational science, in which quantum processors play a dual role: as experimental platforms for probing quantum many-body dynamics and as accelerators within hybrid computational workflows. This combined perspective offers a practical route toward scientifically meaningful quantum advantage before the advent of fully fault-tolerant quantum computing

[1] K. Shinjo, K. Seki, T. Shirakawa, R.-Y. Sun, and S. Yunoki, “Unveiling clean two-dimensional discrete time crystals on a digital quantum computer”, arXiv:2403.16718.
[2] K. Shinjo, K. Seki, and S. Yunoki, “Noise-stabilized discrete time crystals on digital quantum processors”, arXiv:2510.13577.
[3] K. Shinjo, K. Seki, and S. Yunoki, “Quantum synchronization and chimera states in a programable quantum many-body system”, arXiv:2603.11910.
[4] K. Nagao, T. Shirakawa, R.-Y. Sun, P. Prelovsek, and S. Yunoki, “Probing many-body localization crossover in quasiperiodic Floquet circuits on a quantum processor”, arXiv:2603.12675.
[5] J. Robledo-Moreno et al., “Chemistry beyond the scale of exact diagonalization on a quantum-centric supercomputer”, Science Advances 11, eadu9991 (2025).
[6] T. Shirakawa et al., “Closed-loop calculations of electronic structure on a quantum processor and a classical supercomputer at full scale”, arXiv:2511.00224.
[7] P. Yoo ei al., “Extending the handover-iterative VQE to challenging strongly correlated systems: N2 and Fe-S cluster”, arXiv:2601.08137.

Speaker: Seiji Yunoki (RIKEN)

14:45 A challenge for quantum few-body problems using machine learning with quantum annealing machine

Quantum annealing machines are attracting attention as a new type of quantum computer in addition to conventional gate-based quantum computers. They have been introduced to the market by D-Wave company and can also be used on the cloud. Many companies are also considering using and operating them in the future, and it is expected that they will also be practically used more widely in the scientific field.
Accurate computtatinal reproduction of quantum few-body systems such as hadrons,nuclei, atoms, etc have been a central interest in science　because it is fundamental research into understanding quantum systems.
In this talk, I will explain how quantum machine learning can be implemented using a quantum annealing machine to perform calculations on quantum few-body systems, and provide actual calculation examples.

Speaker: Shigeyoshi Aoyama (KEK CRC)

15:10 Break

15:40 Fault-tolerant quantum algorithms for many-body systems

Quantum computers are expected to accelerate various tasks including quantum simulation and sensing, which are holistically referred to as quantum advantage. In this talk, we review the current state-of-the-art in fault-tolerant quantum algorithms, such as the quantum signal processing in the context of state preparation and Hamiltonian simulation, and dissipative quantum simulation for finite-temperature states. Furthermore, we envision the timeline for its realization in hardwares.

Speaker: Nobuyuki Yoshioka (ICEPP, The University of Tokyo)

16:25 → 18:00 Poster Session

18:00 → 20:00 Reception

Tuesday 19 May

09:30 → 13:25 Session 3

Convener: Toshiaki Inada (ICEPP, The University of Tokyo)

09:30 Superconducting qubits and cavities for DM sensors at QUP-KEK

As governments and major technology companies lead development on quantum computers, underlying quantum technologies have undergone revolutionary advances. While many of these technologies are, in principle, applicable to particle physics experiments, applications remain limited so far.
In this talk, we will introduce the dark matter search program based on superconducting qubits conducted by KEK/QUP as an example, I will provide an overview of the new possibilities for particle physics experiments enabled by state-of-the-art quantum technologies.

Speaker: Tatsumi Nitta (KEK-QUP)

10:15 High-Q Three-Dimensional Superconducting Cavities: Development and Applications for Quantum Technologies

Quantum technologies based on superconducting circuits have advanced rapidly in recent years. Recent progress has increasingly underscored the importance of materials and microscopic loss mechanisms, particularly dielectric loss and two-level-system physics, as planar superconducting qubits enter the millisecond regime. Advances in these directions have also driven further improvements in high-Q three-dimensional superconducting cavities for quantum applications. Their exceptional quality factors and low loss enable applications such as the characterization of interface dielectric loss, long-lived quantum memories, and searches for dark photon dark matter.
In this talk, I will present our efforts to improve the quality factor of three-dimensional superconducting cavities and discuss experiments on bosonic quantum error correction in a cavity-transmon architecture, where logical information is encoded in cavity Fock states and their superpositions.

Speaker: Takaaki Takenaka (NTT)

11:00 Break

11:30 TBD

Speaker: Atsushi Noguchi (The University of Tokyo)

12:15 Searches for New Physics Using Ytterbium

Extremely high precision measurement of frequency ratio and difference realized by optical atomic clocks enables us to perform not only accurate time-keeping but also searches for new physics. One of the earliest works on this is the search for time variation of fundamental constants, such as the proton-to-electron mass ratio and the fine structure constant. Recent trend is to precisely measure isotope shifts to investigate new force between an electron and a neutron. Ytterbium is one of the most popular atoms for these purposes. Initially, transitions in Yb⁺ ions were utilized. Recently, the new clock transition at 431 nm with an f electron excited is expected to serve as an important role in these topics.

In this talk, I first describe a brief overview of the topic. I then discuss my recent work on the 431 nm transition and a search for the new force between an electron and a neutron. Finally, I will describe the future direction of the research including the search for time variation of fundamental constants in my group.

Speaker: Akio Kawasaki (NMIJ/AIST)

12:40 → 14:10 Lunch

14:10 → 17:30 Session 4

Convener: Tatsumi Nitta (KEK-QUP)

14:10 DarQ experiment - Dark matter searches using spontaneous/controlled superconducting qubit excitations

Superconducting qubits are sensitive to noise - from electromagnetic disturbances, impurities in the material, and even cosmic rays can easily perturb their quantum states and induce errors. From the quantum computer point of view, none of these are desirable. On the other hand, this very sensitivity implies that qubits can be used as highly sensitive sensors for weak fields—such as dark matter. DarQ experiment (Dark matter search using Qubits) is a research effort to search for wave-like dark matter using superconducting qubits.
In this talk, the concept, status, and prospects of the experiment are discussed, as well as the possibility of using quantum computers themselves as dark matter detectors.

Speaker: Shion Chen (Grad. School of Sci., Kyoto University)

14:55 A Multi-Front Approach to Advancing High-Energy Physics with Quantum Technologies

High-energy physics (HEP) demands not only experimental probes of known and unknown particles but also an intricate understanding of the theory of gauge fields. At ICEPP, we combine our traditional competency in experimental HEP with a rapidly developing expertise in quantum technologies, both theoretical and experimental, developing multiple research thrusts that cover a wide range of topics from table-top blackholes to real-time simulations of nonabelian lattice gauge theories. This presentation will showcase current activities and longer-term strategies of the lab.

Speaker: Yutaro Iiyama (University of Tokyo (JP))

15:40 Break

16:10 Quantum Error Correction and Lattice gauge theory

We explore relations between quantum error correction and gauge theory. They have a conceptual similarity that quantum error correction provides a redundant description of logical qubits in terms of encoded qubits while gauge theory has a redundancy to describe physical states. Motivated by the conceptual similarity and recent demand for efficient ways to put gauge theories on quantum computers, we develop a comprehensive framework for constructing quantum error correcting codes from Abelian lattice gauge theories using quantum reference frames as a unifying formalism. This talk is mainly based on a joint work with Javier P. Lacambra, Aidan Chatwin-Davies and Philipp A. Hoehn (arXiv:2604.06087).

Speaker: Masazumi Honda (RIKEN)

16:55 A Quantum Algorithm for Measuring Entanglement Asymmetry and Quantum Mpemba Effect

We propose a quantum algorithm to efficiently estimate the entanglement asymmetry, a recently introduced measure of symmetry breaking at the subsystem level that plays a key role in the quantum Mpemba effect. Our protocol combines the SWAP test with ideas from quantum phase estimation and requires a number of measurements independent of the system size, making it suitable for large quantum many-body systems and quantum field theories. As an application, we study the lattice Schwinger model with a θ term and demonstrate that our approach enables the investigation of the quantum Mpemba effect in a quantum field theory setting. We further provide resource estimates for quantum computing implementations.

Speaker: Harunobu Fujimura (大阪大学)

17:20 Summary/Concluding Remarks

Speaker: Masaya Ishino (University of Tokyo (JP))