Population dynamics in sideband cooling of trapped ions outside the Lamb-Dicke regime

Abstract

We present the results of simulations of optical sideband cooling of atomic ions in a trap with a shallow potential well. In such traps, an ion cannot be Doppler cooled near to the Lamb-Dicke regime (${\eta }^2(2n+1)\ll 1$). Outside the Lamb-Dicke regime, the sideband cooling dynamics are altered by the existence of various Fock states where the cooling becomes very slow. A calcium ion trapped in our Penning trap realises such a situation, hence single stage cooling is inefficient to prepare the ion in the motional ground state. For these systems, it is necessary to study the cooling dynamics in detail and we show that it is possible to implement an optimised cooling sequence to achieve efficient ground state cooling. We also present the simulated cooling dynamics of two ions trapped in a Penning trap, where the presence of an additional motional mode requires a complicated cooling sequence in order to cool both axial modes to the ground state simultaneously. Additionally we investigate sideband heating of a single ion in a Penning trap.

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Cited by in corpus (8)

• Penning micro-trap for quantum computing
• Sideband cooling of the radial modes of motion of a single ion in a Penning trap
• Coherently displaced oscillator quantum states of a single trapped atom
• Coherence properties of highly-excited motional states of a trapped ion
• Efficient motional-mode characterization for high-fidelity trapped-ion quantum computing
• Fast Laser Cooling Using Optimal Quantum Control
• Stabilization of cat-state manifolds using nonlinear reservoir engineering
• Pulse optimization for high-precision motional-mode characterization in trapped-ion quantum computers