Takagi Quantum Information Theory Group-University of Tokyo

We work on foundational aspects of quantum information theory, aiming to understand operational significance of quantum properties using the tools in physics, information theory, and computer sciences. We are generally interested in wide range of topics in quantum information, but we have been paricularly focusing on

Quantum resource theories
Quantum entanglement theory
Quantum thermodynamics
Continuous-variable qunatum information
Quantum error correction and mitigation
Quantum algorithms

If you are interested in discussing with us or knowing more about the group, feel free to shoot an email to ryujitakagi[at]g.ecc.u-tokyo.ac.jp

news

2026 Mar	Our work showing that one can achieve the optimal work extraction rate in quantum thermodynamics without knowing the state descritption has been published in Nature Communications. Press release has also been published (in Japanese).
2026 Mar	Our work that formalized projective measurements by an operational concept known as intersubjectivity has been posted on arXiv. Joint work with Shun Umekawa.
2026 Feb	Our work that experimentally demonstrated a spin-cat code and its single-qubit logical operations has been posted on arXiv. Joint work with Toshi Kusano, Kosuke Shibata, Chih-Han Yeh, Keito Saito, Yuma Nakamura, Rei Yokoyama, Takumi Kashimoto, Tetsushi Takano, Yosuke Takasu, and Yoshiro Takahashi.
2026 Feb	Our work that showed the construction of logical Clifford group with transversal and fold-transversal gates has been posted on arXiv. Joint work with Theerapat Tanswannont and Tim Chan.
2025 Oct	Our work that introduced error mitigaiton mehod utilizing the symmetry of quantum channels has been published in PRX Quantum. Joint work with Kento Tsubouchi, Yosuke Mitsuhashi, and Nobuyuki Yoshioka. Press release has also been published (in Japanese).