Optical dipole-force cooling of anions in a Penning trap

Abstract

We discuss the possibility of using optical dipole forces for Sisyphus cooling of ions stored in a Penning trap by addressing the specific case of the molecular cooling candidate ${{\mathrm{C}}_{2}}^{\ensuremath{-}}$. Using a GPU accelerated code for Penning trap simulations, which we extended to include the molecule-light interaction, we show that this scheme can decrease the time required for cooling by an order of magnitude with respect to Doppler cooling. In our simulation we found that a reduction of the axial anion temperature from $10\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ to $50\phantom{\rule{0.28em}{0ex}}\mathrm{mK}$ in around $10\phantom{\rule{0.28em}{0ex}}\mathrm{s}$ is possible. The temperature of the radial degrees of freedom was seen to thermalize to $150\phantom{\rule{0.28em}{0ex}}\mathrm{mK}$. Based on the laser-cooled ${{\mathrm{C}}_{2}}^{\ensuremath{-}}$, a study on the sympathetic cooling of anions with masses 1--50 nucleon was performed, covering relevant candidates for investigations of chemical anion reactions at ultracold temperatures as well as for antimatter studies.