Physicists build world’s smallest engine

For most people the word ‘engine’ conjures up images of what lies under the bonnet of a car, or of a steam locomotive pulling a train. But a team of physicists, including TherMiQ researcher Prof Eric Lutz, have just built an engine from a single atom – some 10,000 times smaller than the previous record holder.

Large-scale engines generally operate by converting the thermal energy in a fluid into work, a process involving an exchange between hot and cold ‘reservoirs’. To create the same effect at the level of a single atom, the researchers used electric field noise to provide the heat, and a laser cooling technique to provide the cold reservoir. The fluid substance of the engine is composed of a charged ion, trapped in a conic electric trap, where the noise is turned up at one end of the trap and the laser-cooling turned on at the other. The atom, as a result, shoots up and down the cone rather like a piston.

This single-atom engine, admits lead author Johannes Roßnagel, is not intended to be put to practical use. But the research could provide great insight into the thermodynamics of single particles.

The paper setting out the results, ‘A single-atom heat engine’, was published by the prestigious Science journal today, 15 April 2016.


Johannes Roßnagel, Samuel T. Dawkins, Karl N. Tolazzi, Obinna Abah, Eric Lutz, Ferdinand Schmidt-Kaler, Kilian Singer, ‘A single-atom heat engine’, Science, 15 Apr 2016: Vol. 352, Issue 6283, pp. 325-329

DOI: 10.1126/science.aad6320