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RIKEN Hakubi Research Teams Analytical Quantum Complexity RIKEN Hakubi Research Team

RIKEN Hakubi Team Leader: Tomotaka Kuwahara (Ph.D.)

Research Summary

Tomotaka Kuwahara (Ph.D.)

The field of revealing the computational complexity of quantum many-body system simulations when using a classical computer (or quantum computer) is called Hamiltonian Complexity. In particular, from the viewpoint of quantum supremacy of quantum computers and quantum algorithms employing NISQ (i.e., a small quantum computer without error correction), Hamiltonian complexity has become one of the most important research topics in the field of quantum information. Our research aims to solve open mathematical problems in Hamiltonian complexity.

Selected Publications

  • 1. T. Kuwahara, K. Saito,
    "Exponential Clustering of Bipartite Quantum Entanglement at Arbitrary Temperatures"
    Physical Review X, 12, 021022 (2022)
  • 2. T. Minato, K. Sugimoto, T. Kuwahara, and K. Saito,
    "Fate of Measurement-Induced Phase Transition in Long-Range Interactions"
    Phys. Rev. Lett. 128, 010603 (2022)
  • 3. T. Kuwahara, K. Saito,
    "Lieb-Robinson Bound and Almost-Linear Light Cone in Interacting Boson Systems"
    Phys. Rev. Lett. 127, 070403 (2021)
  • 4. A. Anshu, S. Arunachalam, T. Kuwahara, M. Soreimanifar (alphabet order),
    "Sample-efficient learning of quantum many-body systems,"
    Nature Physics, 17, 931–935 (2021)
  • 5. T. Kuwahara, A. M. Alhambra, and A. Anshu,
    "Improved thermal area law and quasi-linear time algorithm for quantum Gibbs states,"
    Physical Review X, 11, 11047 (2021)
  • 6. T. Kuwahara, K. Saito,
    "Absence of Fast Scrambling in Thermodynamically Stable Long-Range Interacting Systems"
    Physical Review Letters, 126, 030604 (2021)
  • 7. T. Kuwahara, K. Saito,
    "Area law of noncritical ground states in 1D long-range interacting systems"
    Nature Communications, 11 4478 (2020)
  • 8. T. Kuwahara, K. Saito,
    "Strictly Linear Light Cones in Long-Range Interacting Systems of Arbitrary Dimensions,"
    Physical Review X, 10, 031010 (2020)
  • 9. T. Kuwahara, K. Kato, F. Brandao,
    "Clustering of Conditional Mutual Information for Quantum Gibbs States above a Threshold Temperature,"
    Physical Review Letters, 124, 220601 (2020)
  • 10. T. Kuwahara, Keiji Saito,
    "Eigenstate Thermalization from the Clustering Property of Correlation"
    Physical Review Letters, 124, 200604 (2020)

Recent Research Results

Related Links

Lab Members

Principal investigator

Tomotaka Kuwahara
RIKEN Hakubi Team Leader

Contact Information

RIKEN Main Research Building 335,337
2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Email: tomotaka.kuwahara [at] riken.jp