Title
Numerical Methods and Comparison for the Dirac Equation in the Nonrelativistic Limit Regime.
Abstract
We analyze rigorously error estimates and compare numerically spatial/temporal resolution of various numerical methods for the discretization of the Dirac equation in the nonrelativistic limit regime, involving a small dimensionless parameter \(0<\varepsilon \ll 1\) which is inversely proportional to the speed of light. In this limit regime, the solution is highly oscillatory in time, i.e. there are propagating waves with wavelength \(O(\varepsilon ^2)\) and O(1) in time and space, respectively. We begin with several frequently used finite difference time domain (FDTD) methods and obtain rigorously their error estimates in the nonrelativistic limit regime by paying particular attention to how error bounds depend explicitly on mesh size h and time step \(\tau \) as well as the small parameter \(\varepsilon \). Based on the error bounds, in order to obtain ‘correct’ numerical solutions in the nonrelativistic limit regime, i.e. \(0<\varepsilon \ll 1\), the FDTD methods share the same \(\varepsilon \)-scalability on time step and mesh size as: \(\tau =O(\varepsilon ^3)\) and \(h=O(\sqrt{\varepsilon })\). Then we propose and analyze two numerical methods for the discretization of the Dirac equation by using the Fourier spectral discretization for spatial derivatives combined with the symmetric exponential wave integrator and time-splitting technique for temporal derivatives, respectively. Rigorous error bounds for the two numerical methods show that their \(\varepsilon \)-scalability is improved to \(\tau =O(\varepsilon ^2)\) and \(h=O(1)\) when \(0<\varepsilon \ll 1\). Extensive numerical results are reported to support our error estimates.
Year
DOI
Venue
2017
10.1007/s10915-016-0333-3
J. Sci. Comput.
Keywords
Field
DocType
Dirac equation, Nonrelativistic limit regime, Finite difference time domain method, Symmetric exponential wave integrator, Time splitting, Spectral method, $$\varepsilon $$ε-Scalability
Discretization,Dirac equation,Mathematical analysis,Spectral method,Numerical analysis,Temporal resolution,Mathematics
Journal
Volume
Issue
ISSN
71
3
1573-7691
Citations 
PageRank 
References 
1
0.37
9
Authors
4
Name
Order
Citations
PageRank
Weizhu Bao163895.92
Yongyong Cai28011.43
Xiaowei Jia310.37
Qinglin Tang4537.29