Analysis of quantum computers that have constraints on memory accesses

• Project/Area Number: 16K00007
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Theory of informatics
• Research Institution: Yamagata University
• Principal Investigator: Nakanishi Masaki 山形大学, 地域教育文化学部, 教授 (40324967)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Discontinued (Fiscal Year 2019)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
• Keywords: 量子計算機 / 量子オートマトン / 量子計算機シミュレータ / 量子アルゴリズム / 量子コンピュータ / 量子コンピュータシミュレータ / affineオートマトン / カウンタオートマトン / 量子計算モデル / FPGA / GPGPU / 情報基礎 / アルゴリズム

Outline of Final Research Achievements

We analyzed the computational power of quantum computers that have restrictions on memory accesses. It was shown that there is a quantum automaton that can recognize a certain language, while the classical counterpart cannot recognize it. This implies that there is a function that can be computed by a quantum automaton, while it cannot be computed by the classical counterpart; quantum computers can be more powerful than classical computers.
Moreover, we developed several methods that boost quantum computer simulators.

Academic Significance and Societal Importance of the Research Achievements

量子計算機は従来の計算機と比べて高速に問題を解くことができるため，大きな注目を集めている．量子計算機は量子状態を利用するため，その実装には高度な技術が必要となる．そのため，将来，実用規模の量子計算機が実現される初期の段階では，その動作に様々な制約が課されることが予想され，特に量子メモリについては様々な制約の下でのみアクセスが可能になると考えられる．本研究成果は，そのような実現初期段階の量子計算機を効率的に使うための指針となりうる．

Research Products

• [Int'l Joint Research] National University of Asuncion(パラグアイ)
• [Int'l Joint Research] University of Latvia(ラトビア)
• [Int'l Joint Research] National University of Asuncion(パラグアイ)
• [Int'l Joint Research] University of Latvia(Latvia)
• [Journal Article] Computational Complexity of Space-Bounded Real Numbers (2018)
  • Author(s): Masaki Nakanishi and Marcos Villagra
  • Journal Title: arXiv Volume: arXiv:1805.02572 Pages: 1-16
  • Open Access / Int'l Joint Research
• [Journal Article] Quantum pushdown automata with garbage tape (2018)
  • Author(s): Masaki Nakanishi
  • Journal Title: International Journal of Foundations of Computer Science Volume: 印刷中
  • Peer Reviewed
• [Journal Article] Exact affine counter automata (2017)
  • Author(s): Masaki Nakanishi, Kamil Khadiev, Krisjanis Prusis, Jevgenijs Vihrovs, and Abuzer Yakaryilmaz
  • Journal Title: Proc. of the 15th International Conference on Automata and Formal Languages Volume: EPTCS 252 Pages: 205-218
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Affine counter automata (2017)
  • Author(s): Masaki Nakanishi, Abuzer Yakaryilmaz
  • Journal Title: arXiv Volume: arXiv:1703.04281 Pages: 1-15
  • Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Quantum Query Complexity of Almost All Functions with Fixed On-Set (2016)
  • Author(s): A. Ambainis, K. Iwama, M. Nakanishi, H. Nishimura, R. Raymond, S. Tani, S. Yamashita
  • Journal Title: Computational Complexity Volume: 25 Issue: 4 Pages: 723-735
  • DOI: 10.1007/s00037-016-0139-6
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Cache-aware quantum circuit simulation on a GPGPU (2016)
  • Author(s): M. Nakanishi, N. Morioka, and K. Shoji
  • Journal Title: Proc. of the 16th Asian Quantum Information Science Conference (AQIS2016) Volume: n/a Pages: 11-12
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] A hardware architecture for simulating the HHL algorithm (2019)
  • Author(s): Kimika Beppu, Kanae Nakabayashi, and Masaki Nakanishi
  • Organizer: 22nd Annual Conference on Quantum Information Processing
  • Int'l Joint Research
• [Presentation] FPGAを用いた正則グラフ上の量子ウォークのシミュレーション (2016)
  • Author(s): 中鉢大喜, 中西正樹
  • Organizer: 第35回量子情報技術研究会
  • Place of Presentation: 高エネルギー加速器研究機構
  • Year and Date: 2016-11-24