arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2602.04553nucl-thcs.LGphysics.comp-ph

外部复数缩放使物理引导的神经网络用于量子散射

Exterior complex scaling enables physics-informed neural networks for quantum scattering

Tongji University(同济大学);Institute of Modern Physics, Chinese Academy of Sciences(中国科学院近代物理研究所)

Jin Lei

AI总结:

本文提出通过外部复数缩放将散射边界条件转化为指数衰减波,使物理引导的神经网络首次应用于核反应问题,实现了高精度的相移计算和S矩阵准确性。

摘要:

物理引导的神经网络(PINNs)已发展为求解微分方程的强大工具,但其在核散射中的应用受散射波函数振荡、非衰减性质的阻碍。本文证明外部复数缩放(ECS)可将散射边界条件转化为适合神经网络求解的指数衰减波,使PINNs首次解决核反应问题。本文开发了驱动方程公式,其中源项被限制在实轴上,避免将核势解析延拓到复平面的需要。该方法在核子-核散射(n+⁴⁰Ca在E_lab=20 MeV)中验证,使用21个部分波,实现强吸收通道(ℓ ≤ 4)的相移精度Δδ ≲ 0.1°,以及所有通道至ℓ=10的相移精度Δδ ≤ 0.60°。进一步在重离子散射(⁶Li+²⁰⁸Pb在40 MeV)中演示,使用41个部分波和强库仑效应,弱源通道的自适应锚点暖降算法实现了S矩阵平均精度|Δ|S_ℓ|| ≈ 3 × 10⁻³,涵盖整个角动量范围,包括吸收到透明过渡区。本文为扩展PINNs到逆问题奠定了基础,其中端到端可微性使直接拟合光学势参数、耦合通道反应和少体散射成为可能,传统网格方法在此类问题中面临指数级扩展。

英文摘要:

Physics-informed neural networks (PINNs) have emerged as a powerful tool for solving differential equations, yet their application to nuclear scattering has been hindered by the oscillatory, non-decaying nature of scattering wave functions. In this work, I demonstrate that exterior complex scaling (ECS) transforms scattering boundary conditions into exponentially decaying waves suitable for neural network solutions, enabling PINNs to solve nuclear reaction problems for the first time. I develop a driven-equation formulation where the source term is confined to the real axis, avoiding the need to analytically continue nuclear potentials into the complex plane. The method is validated on nucleon-nucleus scattering (n+$^{40}$Ca at $E_{\text{lab}}=20$~MeV) with 21 partial waves, achieving phase shift accuracy of $Δδ\lesssim 0.1^\circ$ for the strongly absorbed channels ($\ell \leq 4$) and $Δδ\leq 0.60^\circ$ for all channels up to $\ell = 10$, when compared to conventional solvers. I further demonstrate the approach on heavy-ion scattering ($^6$Li+$^{208}$Pb at 40~MeV) with 41 partial waves and strong Coulomb effects, where an auto-adaptive anchor warm-down for weak-source channels yields a mean S-matrix accuracy of $|Δ|S_\ell|| \approx 3 \times 10^{-3}$ across the full angular momentum range, including the absorption-to-transparency transition region. This work establishes the foundation for extending PINNs to inverse problems where end-to-end differentiability enables direct fitting of optical potential parameters, coupled-channel reactions, and few-body scattering where traditional grid methods face exponential scaling.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑