Order and chaos in laser cooled trapped ions

Abstract

The authors have investigated two physical mechanisms that underlie and explain the behavior of ion crystals. First, they have shown that deterministic chaos can be responsible for phase transitions between the ordered (crystal) state and the disordered (cloud) state. The crystal-cloud transition is viewed as an order-chaos transition. Chaos arises from the nonlinear interaction of Coulomb repulsion with the oscillating trap potential. Second, they have observed an unexpected laser cooling instability that limits the size of ion crystals in RF traps and can also initiate an order-chaos transition.