Local equilibria and state transfer of charged classical particles on a   helix in an electric field
  We explore the effects of a homogeneous external electric field on the static properties and dynamical behavior of two charged particles confined to a helix. In contrast to the field-free setup which provides a separation of the center-of-mass and relative motion, the existence of an external force perpendicular to the helix axis couples the center-of-mass to the relative degree of freedom leading to equilibria with a localized center of mass. By tuning the external field various fixed points are created and/or annihilated through different bifurcation scenarios. We provide a detailed analysis of these bifurcations based on which we demonstrate a robust state transfer between essentially arbitrary equilibrium configurations of the two charges that can be induced by making the external force time-dependent. 
J. Plettenberg, J. Stockhofe, A. V. Zampetaki, P. Schmelcher
physics.class-ph cond-mat.other physics.atom-ph