A new approach to laser cooling vastly extends this technique to many more species and even macroscopic objects, as demonstrated by cooling a highly charged ion to under 200 $\ensuremath{\mu}$K---close to the quantum-mechanical ground state.

arXiv:2102.12427Physical Review XDec 10, 202125 citations

Sideband Thermometry of Ion Crystals

Ivan Vybornyi, Laura S. Dreissen, Dominik Kiesenhofer +7 more

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arXiv:2308.05158

Indirect Cooling of Weakly Coupled Trapped-Ion Mechanical Oscillators

Pan‐Yu Hou, Jenny J. Wu, Stephen D. Erickson, Giorgio Zarantonello, A. D. Brandt, Daniel C. Cole, A. C. Wilson, D. H. Slichter, Dietrich G. Leibfried

Published Aug 9, 2023• 0 citations

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Abstract

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crystals. This approach can be generally applied to any Coulomb crystal where certain motional modes cannot be directly cooled efficiently, including crystals containing molecular ions, highly-charged ions, charged fundamental particles, or charged macroscopic objects.

DOI: 10.48550/arxiv.2308.05158

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1/N^2

with the number of ions. By iterating the pulses, we measure mean phonon occupations

<2\cdot10^{-4}

. For large crystals in the coherent regime, we further show that the spin-motion dynamics becomes largely independent of the initial phonon statistics. Through spin measurements, the state-swap mechanism can be utilized to probe the phonon distribution in the mode.