Stepwise relaxation and stochastic precession in degenerate oscillators dispersively coupled to particles

Artikel i vetenskaplig tidskrift, 2017

By numerical integration, we study the relaxation dynamics of degenerate harmonic oscillator modes dispersively coupled to particle positions. Depending on whether the effective inertial potential induced by the oscillators keeps the particles confined or if the particle trajectories traverse the system, the local oscillator energy dissipation rate changes drastically. The inertial trapping, release, and retrapping of particles result in a characteristic stepwise relaxation process, with alternating regions of fast and slow dissipation. To demonstrate this phenomenon we consider first a one-dimensional minimal prototype model which displays these characteristics. We then treat the effect of dispersive interaction in a model corresponding to an adsorbate diffusing on a circular membrane interacting with its three lowest vibrational modes. In the latter model, stepwise relaxation appears only in the presence of thermal noise, which also causes a slow-in-time stochastic precession of the mixing angle between the degenerate eigenmodes.