Professor Masaki Oshikawa has been selected to receive the 2025 (71st) Nishina Memorial Prize. Established in 1955 to commemorate Dr. Yoshio Nishina, known as the “Father of Modern Physics in Japan,” the Nishina Memorial Prize is one of the most prestigious distinctions in Japanese physics today. No more than three prizes are awarded each year, recognizing achievements which have earned broad international acclaim across the full spectrum of physics.

Professor Oshikawa, together with Professor Hal Tasaki of Gakushuin University, have been selected for their groundbreaking work on “theoretical and mathematical studies of quantum spin systems”. The award ceremony is scheduled to take place on December 5th.

Professor Oshikawa established that the gapped phase of an integer-spin chain predicted by Haldane is a symmetry-protected topological (SPT) phase for odd-integer spins, thereby clarifying the topological nature of the Haldane conjecture. He further extended the closely related Lieb–Schultz–Mattis (LSM) theorem into a powerful and widely applicable form—one that constrains the possible quantum phases in arbitrary dimensions based on the (in)commensurability of particle density. This generalized LSM framework has become a universal guiding principle in the search for non-trivial quantum phases, including topologically ordered states.

Together, the achievements of Professors Oshikawa and Tasaki have significantly deepened the understanding of the Haldane conjecture and helped pioneer modern research on topological phases. Their contributions, which profoundly advanced our theoretical grasp of quantum spin and other many-body systems through mathematically rigorous analysis, are honored with this year’s Prize.

Related papers

1. I. Affleck, T. Kennedy, E. H. Lieb, and H. Tasaki, “Rigorous results on valence-bond ground states in antiferromagnets”, Phys. Rev. Lett. 59, 799 (1987); “Valence bond ground states in isotropic quantum antiferromagnets”, Commun. Math. Phys. 115, 477 (1988).
2. T. Kennedy and H. Tasaki, “Hidden Z₂×Z₂ symmetry breaking in Haldane-gap antiferromagnets”, Phys. Rev. B 45, 304 (1992).
3. M. Oshikawa, “Hidden Z₂×Z₂ symmetry in quantum spin chains with arbitrary integer spin”, J. Phys.: Condens. Matter 4, 7469 (1992).
4. F. Pollmann, A. M. Turner, E. Berg, and M. Oshikawa, “Entanglement spectrum of a topological phase in one dimension”, Phys. Rev. B 81, 064439 (2010); F. Pollmann, E. Berg, A. M. Turner, and M. Oshikawa, “Symmetry protection of topological phases in onedimensional quantum spin systems”, Phys. Rev. B 85, 075125 (2012).
5. M. Oshikawa, “Commensurability, excitation gap, and topology in quantum many-particle systems on a periodic lattice”, Phys. Rev. Lett. 84, 1535 (2000).

Related pages

• Nishina Memorial Foundation
• Oshikawa Group, ISSP, UTokyo
• 2025.10.03UTokyoFOCUSISSP NewsVisit and Special Colloquium by Professor F. Duncan M. Haldane, Nobel Laureate in Physics (2016)