The smaller the better, and in a world of fast-developing technology, that's called innovation. Just this month, a desk-sized turbine capable of powering a small town was announced to be under development. A few days later, a heat engine powered by only a single atom comes onto the scene.
Using a "Paul trap" (an ion trap that captures charged particles using electric fields), the team captured an electrically charged calcium ion, which was heated through an electrically generated noise, and cooled using a laser beam. The result? A thermodynamic cycle.
The repeated heating and cooling caused the atom to move back and forth within the trap, working like a piston in an engine. The results showed that this extremely small engine generates power up to 10-22 watts at a percent efficiency of 0.3. If scaled up from the mass of the atom, this energy output could equal that of a car engine.
Moreover, the atom not only generates power, but stores it as well.
Further research on how to improve the single-atom engine and its possible applications are already being planned out by the work group. According to Johannes Rossnagel, first author of the study, they could also create a single-atom refrigerator by reversing the cycle that the atom was subjected to.
However, main goal of the study was to observe thermodynamics on a particle level. The team announced their work in Physical Review Letters two years ago (2014), which they now have accomplished, opening new possibilities for constructing novel types of engines on a much smaller scale.