  NRQED approach to the fine and hyperfine structure corrections of order
m$\alpha$ 6 and m$\alpha$ 6 (m/M)-Application to the hydrogen atom The NRQED
approach is applied to the calculation of relativistic corrections to the fine
and hyperfine structure of hydrogenlike atoms at orders m$\alpha$ 6 and
m$\alpha$ 6 (m/M). Results are found to be in agreement with those of the
relativistic theory. This confirms that the derived NRQED effective potentials
are correct, and may be used for studying more complex atoms or molecules.
Furthermore, we verify the equivalence between different forms of the NRQED
Lagrangian used in the literature.
