Polarization of ions under geometric confinement in the strong-interacting regime: a two-ring model study.

We study the polarization and electrostatic interactions of an ionic system under geometric confinement in the strong-interacting regime. The geometric confinement is introduced via a simple two-ring model, where ions of each species are confined on a ring, respectively. The observed polarization curve exhibits staircase transitions in the low-temperature regime, due to the crossover between energy local minima. We examine the criterion for the validity of the linear response theory and introduce a simple two-state picture that illustrates the signatures of the crossover phenomena.