Dynamics of ferromagnets: averaging methods, bifurcation diagrams, and thermal noise effects

Driving nanomagnets by spin-polarized currents offers exciting prospects in magnetoelectronics, but the response of the magnet to such currents
remains poorly understood. For a single domain ferromagnet, I will show that an averaged equation describing the diffusion of energy on a
graph captures the low-damping dynamics of these systems. In particular, I compute the mean times of thermally assisted magnetization reversals
in the finite temperature system, giving explicit expressions for the effective energy barriers conjectured to exist. I will then outline the problem of extending the analysis to spatially non-uniform magnets, leading to a transition state theory for infinite dimensional Hamiltonian
systems.