Our work on realizing a single-atom heat engine in the quantum world has been published in Nature Communications (DOI:10.1038/s41467-021-22222-z). We realize an Otto cycle in the spin-manifold of single Caesium atoms. We can show that the engine not only works at high efficiency, but it also combines high power output and small output power fluctuations. Experimentally, we have achieved this by coupling the quantized heat exchange between engine and an atomic bath to spin exchange processes. Thereby we could at every time deduce the amount of heat exchanged from the spin state of the engine. More details can be found in the press release of TUK or in our paper.