Perturbations and quantum relaxation
  We investigate whether small perturbations can cause relaxation to quantum
equilibrium over very long timescales. We consider in particular a
two-dimensional harmonic oscillator, which can serve as a model of a field mode
on expanding space. We assume an initial wave function with small perturbations
to the ground state. We present evidence that the trajectories are highly
confined so as to preclude relaxation to equilibrium even over very long
timescales. Cosmological implications are briefly discussed.
