Laser Cooling of Trapped Ions in the High-Temperature Regime

We employ a semiclassical framework to explore the motional dynamics of trapped ion crystals with arbitrarily high energy, including the effects of laser cooling. There are two major benefits to this approach: (1) it is non-perturbative, and hence captures dynamics beyond the Lamb-Dicke regime, and (2) it reduces the computational complexity by tracking a small number of phase space coordinates instead of several high-dimensional Fock spaces. This allows us to accurately and efficiently model a variety of exotic phenomena, such as the recrystallization of ion clouds which have been imparted with thousands of motional quanta due to collisions with background particles, a potentially limiting factor of trapped ion quantum computers. We show that this approach quantitatively agrees with the familiar quantum rate equation method when operating in the Lamb-Dicke regime, but also predicts non-exponential cooling and capture ranges for EIT cooling.