2025-12-02 東北大学
図1．最適輸送。(a) 微小粒子の操作を「粒子位置の確率分布の変化」とみなす。初期分布と終分布の選び方に応じて、多様な操作を表現できる。(b) 理論的には、分布を地図上の点に見立て、分布間を結ぶ最短経路が、最小エネルギーコストを実現する最適輸送に対応し、分布間の「距離」がエネルギーの最小コストに対応する。(c) 1次元の場合は、左側は左に、右側は右にといったように、分布の「並び」を変えずに各部分を一定の速度で輸送するのが「最適輸送」。
＜関連情報＞
- https://www.tohoku.ac.jp/japanese/2025/12/press20251202-01-ene.html
- https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20251202_01web_ene.pdf
- https://www.nature.com/articles/s41467-025-66519-9
熱力学的に最適な輸送による最小の散逸を実験的に達成する Experimentally achieving minimal dissipation via thermodynamically optimal transport
Shingo Oikawa,Yohei Nakayama,Sosuke Ito,Takahiro Sagawa & Shoichi Toyabe
Nature Communications Published:01 December 2025
DOI:https://doi.org/10.1038/s41467-025-66519-9
Abstract
Optimal transport theory, originally developed in the 18th century for civil engineering, has since become a powerful optimization framework across disciplines, from generative AI to cell biology. In physics, it has recently been shown to set fundamental bounds on thermodynamic dissipation in finite-time processes. This extends beyond the conventional second law, which guarantees zero dissipation only in the quasi-static limit and cannot characterize the inevitable dissipation in finite-time processes. Here, we experimentally realize thermodynamically optimal transport using optically trapped microparticles, achieving minimal dissipation within a finite time. As an application to information processing, we implement the optimal finite-time protocol for information erasure, confirming that the excess dissipation beyond the Landauer bound is exactly determined by the Wasserstein distance — a fundamental geometric quantity in optimal transport theory. Furthermore, our experiment achieves the bound governing the trade-off between speed, dissipation, and accuracy in information erasure. To enable precise control of microparticles, we develop scanning optical tweezers capable of generating arbitrary potential profiles. These results provide guiding principles for information processing with saturating the trade-off.
