Jc. Shi et Yt. Yan, EXPLICITLY INTEGRABLE POLYNOMIAL HAMILTONIANS AND EVALUATION OF LIE TRANSFORMATIONS, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 48(5), 1993, pp. 3943-3951
We have found that any homogeneous polynomial can be written as a sum
of integrable polynomials of the same degree, with which each associat
ed polynomial Hamiltonian is integrable, and the associated Lie transf
ormation can be evaluated exactly. An integrable polynomial factorizat
ion has thus been developed to convert a sympletic map in the form of
a Dragt-Finn factorization into a product of exactly evaluable Lie tra
nsformations associated with integrable polynomials. Having a small nu
mber of factorization bases of integrable polynomials enables one to c
onsider a factorization with the use of high-order symplectic integrat
ors so that a symplectic map can always be evaluated with the desired
accuracy. The results are significant for studying the long-term stabi
lity of beams in accelerators.