  Quantum fluctuations are of central importance in itinerant ferromagnets; in
the case of the Stoner Hamiltonian, with contact interactions, they deliver a
rich phase diagram featuring a first order ferromagnetic transition preempted
by a spin spiral and a paired density wave. However, to date all analyses of
fluctuation corrections neglect the finite ranged nature of the Coulomb
interaction. We develop the formalism to consider the effects of fluctuations
with a realistic screened Coulomb potential. The finite ranged interaction
suppresses the tricritical point temperature of the first order ferromagnetic
transition, bringing theory into line with experiment, whilst retaining the
exotic spin spiral and paired density wave. In an ultracold atomic gas a finite
ranged interaction damps the competing molecular instability, permitting the
observation of ferromagnetic correlations.
