The Complete Characterization of Fourth-Order Symplectic Integrators with Extended-Linear Coefficients

TL;DR

This paper provides a complete analytical characterization of fourth-order symplectic integrators with extended-linear coefficients, simplifying their construction and understanding for various applications.

Contribution

It introduces an extended-linear formulation that fully characterizes fourth-order symplectic integrators, enabling straightforward derivation of forward and non-forward algorithms.

Findings

Analytical form simplifies proofs of properties.

Allows easy construction of algorithms with arbitrary operators.

Most fourth-order forward integrators derived analytically.

Abstract

The structure of symplectic integrators up to fourth-order can be completely and analytical understood when the factorization (split) coefficents are related linearly but with a uniform nonlinear proportional factor. The analytic form of these {\it extended-linear} symplectic integrators greatly simplified proofs of their general properties and allowed easy construction of both forward and non-forward fourth-order algorithms with arbitrary number of operators. Most fourth-order forward integrators can now be derived analytically from this extended-linear formulation without the use of symbolic algebra.