The contents of the paper are explained by Christian Will in this video abstract: Link to YouTube
We study the cooling effect of laser-cooled beryllium ions that are coupled via image currents through a wire to a single trapped proton. A resonator (LC circuit) enhances the image currents to speed up the cooling rate at the cost of introducing noise with 10 K temperature - counteracting the cooling. In our study, we find the coupling the beryllium ions with a large detuning from the resonator can reduce the temperature by a factor 1000 below one of the LC circuit. The implementation of this cooling scheme will be a significant step forward towards high-precision measurements on ultra-cold protons and antiprotons!