German physicists build smallest engine consisting of one atom

German physicists have built the world's smallest heat engine that uses just a single particle, Johannes Gutenberg University of Mainz announced on Friday.

A team of researchers led by Kilian Singer, head of the project at Mainz University, used a type of ion trap to capture a single electrically charged calcium atom, which can be heated with the help of electrically-generated noise and cooled by using a laser beam.

As a result, the atom is subjected to a thermodynamic cycle, meaning the particle moves back and forth within the trap, thus replicating the stroke of a typical engine. The atom not only acts in the same way as an engine, but also stores the energy.

The researchers state in their publication that their single particle engine can generate power of 10-22 watts and operates at 0.3 percent efficiency. If the power of the single atom engine was scaled up from the tiny mass of an atom, its output would be equivalent to that of a car engine.

"By reversing the cycle, we could even use the device as a single atom refrigerator and employ it to cool nano systems coupled to it," explained Johannes Rossnagel, first author of the study.

The project is part of the "Single ion heat engine" project funded through a research grant of the German Research Foundation and received further funding within the "Atomic nano assembler" project funded by the Volkswagen Foundation.

The study has been published in the latest edition of the journal Science. Endit