How it works An atom in a cavity between two mirrors (left) acts as a heat engine in a driven-dissipative quantum system in which energy is continuously added and lost to the environment. The fluctuations in the escaping light (centre) are reduced (right) if only the atom but not the light is described quantum mechanically. (Courtesy: Enrique Sahagún/Scixel / University of Basel, Department of Physics)"> How it works An atom in a cavity between two mirrors (left) acts as a heat engine in a driven-dissipative quantum system in which energy is continuously added and lost to the environment. The fluctuations in the escaping light (centre) are reduced (right) if only the atom but not the light is described quantum mechanically. (Courtesy: Enrique Sahagún/Scixel / University of Basel, Department of Physics)

Can engines made of atoms and light do useful work?…