2023 Fiscal Year Final Research Report

Nonequilibrium quantum thermodynamics of information processing in small scale quantum device circuits

Research Project

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Project/Area Number	20H01827
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 13010:Mathematical physics and fundamental theory of condensed matter physics-related
Research Institution	Mie University
Principal Investigator	Utsumi Yasuhiro 三重大学, 工学研究科, 准教授 (10415094)
Co-Investigator(Kenkyū-buntansha)	都倉康弘筑波大学, 数理物質系, 教授 (20393788) 高橋和孝三重大学, 工学研究科, 特任准教授(研究担当) (70415214)
Project Period (FY)	2020-04-01 – 2024-03-31
Keywords	メゾスコピック量子輸送 / 完全計数統計理論 / 熱力学的不確定性関係・速度限界 / 計算機科学 / 情報量揺らぎ / 非平衡統計力学・揺らぎの定理
Outline of Final Research Achievements	This study aims to explore the physical limits of the performance of small-scale solid-state quantum nano-device circuits by utilizing recent achievements in stochastic thermodynamics, such as thermodynamic uncertainty relations, speed limits, and fluctuation relations. The goal is to identify circuits and protocols that reduce heat production, computation time, and error rates. The following results were obtained: 1) For Brownian computers, it was shown that calculations can be performed without heat generation, requiring only the thermodynamic cost of resetting. An upper bound on the signal-to-noise ratio of the fluctuating computation time was derived based on the thermodynamic uncertainty relations. 2) An upper bound on errors, expressed using the Fisher information metric, was obtained for classical annealing computation. 3) The thermodynamic cost of the switching for the CMOS NAND gate was derived through the stochastic thermodynamics of computation and the fluctuation theorem.
Free Research Field	数理物理および物性基礎関連
Academic Significance and Societal Importance of the Research Achievements	過去20年にわたり、確率熱力学の概念に基づいて、メゾスコピック固体量子素子を用いた低温物理分野で、熱・情報・量子に関する非平衡量子熱統計力学的研究が進展してきた。また、量子計算機や確率ビット回路など、量子素子を集積した回路の実証も進んでいる。本研究は、量子素子の非平衡統計力学を、情報処理機能を持つ量子素子回路に拡張したという学術的意義がある。現在、半導体集積回路ではリーク電流や情報伝達に伴う発熱が問題となっているが、本研究はそれを回避し、熱揺らぎを利用する可能性を示したという点で社会的意義がある。