We study convergence rates of the Trotter splitting $e^{A+L} = \lim_{n \to \infty} (e^{L/n} e^{A/n})^n$ in the strong operator topology. In the first part, we use complex interpolation theory to treat generators $L$ and $A$ of contraction semigroups on Banach spaces, with $L$ relatively $A$-bounded. In the second part, we study unitary dynamics on Hilbert spaces and develop a new technique based on the concept of energy constraints. Our results provide a complete picture of the convergence rates for the Trotter splitting for all common types of Schr\"odinger and Dirac operators, including singular, confining and magnetic vector potentials, as well as molecular many-body Hamiltonians in dimension $d=3$. Using the Brezis-Mironescu inequality, we derive convergence rates for the Schr\"odinger operator with $V(x)=\pm |x|^{-a}$ potential. In each case, our conditions are fully explicit.
翻译:我们研究了强算子拓扑下 Trotter 分裂 $e^{A+L} = \lim_{n \to \infty} (e^{L/n} e^{A/n})^n$ 的收敛速率。在第一部分,我们利用复插值理论处理 Banach 空间上压缩半群的生成元 $L$ 和 $A$,其中 $L$ 相对于 $A$ 是有界的。在第二部分,我们研究了 Hilbert 空间上的酉动力学,并基于能量约束的概念发展了一种新技术。我们的结果为所有常见类型的 Schr\"odinger 算子和 Dirac 算子的 Trotter 分裂收敛速率提供了完整的描述,包括奇异势、约束势和磁矢势,以及三维 ($d=3$) 分子多体 Hamilton 量。利用 Brezis-Mironescu 不等式,我们推导了具有 $V(x)=\pm |x|^{-a}$ 势的 Schr\"odinger 算子的收敛速率。在每种情况下,我们的条件都是完全显式的。