  We consider the semiclassical ballistic sigma-model as an effective theory
describing the quantum mechanics of classically chaotic systems. Specifically,
we elaborate on close analogies to the recently developed semiclassical theory
of quantum interference in chaotic systems and show how semiclassical
'diagrams' involving near action degenerate sets of periodic orbits emerge in
the field theoretical description. We further discuss how the universality
phenomenon (i.e. the fact that individual chaotic systems behave according to
the prescriptions of random matrix theory) can be understood from the
perspective of the field theory.
