量子カオスのモデリング手法に重大な欠陥を発見(IBS Researchers Uncover Major Flaw in Popular Method for Modeling Quantum Chaos)

2025-08-06 韓国基礎科学研究院(IBS)

韓国・基礎科学研究院(IBS)の研究チームが、量子物理で広く使われてきた「共形写像法(CMM)」が、相対論的量子系では誤った結果を導く可能性があることを数学的に証明した。CMMは、相対論的粒子(例えばニュートリノ)が閉じた空間内でどう振る舞うかを模擬するために用いられてきたが、粒子を境界内に閉じ込めるという基本条件を満たしていないことが判明。この問題は、過去にCMMを使って観測された量子スカー(古典軌道の痕跡)の研究結果にも疑問を投げかける。研究チームは、代替手法として「境界積分法(BIM)」を推奨しており、理論物理における近似手法の厳密な検証の重要性を強調している。

量子カオスのモデリング手法に重大な欠陥を発見(IBS Researchers Uncover Major Flaw in Popular Method for Modeling Quantum Chaos)
Figure 1. The left part shows the outgoing current using the eigenstates computed with BIM, the right one those computed with CMM. For the BIM, the outgoing current vanishes along the boundary as required by the BC, whereas for the CMM, it clearly deviates from zero.

<関連情報>

相対論的量子ビリヤードにおける等角写像法の失敗 Failure of the Conformal-Map Method for Relativistic Quantum Billiards

Barbara Dietz
Physical Review Letters  Published: 15 July, 2025
DOI: https://doi.org/10.1103/vj94-kc98

Abstract

In H. Xu et al. [Phys. Rev. Lett. 110, 064102 (2013)], a numerical method is introduced—an extension of the conformal-map method of Robnik [J. Phys. A 17, 1049 (1984)] for nonrelativistic quantum billiards—for the quantization of relativistic neutrino billiards consisting of a massless noninteracting spin-1/2 particle confined to a two-dimensional domain. We demonstrate in this Letter that this method does not provide solutions of the associated Weyl (Dirac) equation, nor does it fulfill the boundary conditions imposed on the spinor eigenfunctions to ensure confinement of the particle to the domain of the billiard. We review in detail the wave equation, boundary conditions, and quantization of neutrino billiards and derivation of relevant equations to make the proof comprehensible for the general reader. Our results are corroborated with numerical ones for nonrelativistic and relativistic quantum billiards whose shapes depend on a parameter, which allows the study of the properties of their eigenstates as the classical dynamics experiences a transition from regular to chaotic dynamics.

1701物理及び化学
ad
ad
Follow
ad
タイトルとURLをコピーしました