A single-atom heat engine

TLDR

We report the experimental realization of a single‑atom heat engine. An ion in a tapered linear Paul trap is alternately coupled to hot and cold reservoirs, its output power drives a harmonic oscillation, and direct measurements of the ion dynamics reveal the thermodynamic cycles for various temperature differences. The engine achieves up to 342 yJ of power and 0.28 % efficiency, matching analytical predictions and demonstrating that thermal machines can be reduced to the ultimate limit of single atoms.

Abstract

We report the experimental realization of a single-atom heat engine. An ion is confined in a linear Paul trap with tapered geometry and driven thermally by coupling it alternately to hot and cold reservoirs. The output power of the engine is used to drive a harmonic oscillation. From direct measurements of the ion dynamics, we determine the thermodynamic cycles for various temperature differences of the reservoirs. We use these cycles to evaluate power $P$ and efficiency $\eta$ of the engine, obtaining up to $P=342\,$yJ and $\eta=0.28 \,\%$, consistent with analytical estimations. Our results demonstrate that thermal machines can be reduced to the ultimate limit of single atoms.