World's tiniest engine is the size of an ATOM: Breakthrough paves the way for powerful quantum machines

Scientists have created the smallest engine ever, in which the piston and connecting rod are replaced by a single atom of calcium.

By alternately heating and cooling the electrically-charged atom, an ion of calcium-40, they were able to turn heat energy into useful work.

In principle, this is exactly the same process as occurs in the petrol-powered internal combustion engine in a car, but this unimaginably small motor could prove to be many times more efficient .... http://www.dailymail.co.uk