Putting Quantum Systems to Work

Engines in cars and airplanes are thermal machines that are capable of doing work. Scientists have recently demonstrated the existence of so-called quantum thermal machines, tiny versions of engines and refrigerators consisting of only a few quantum-mechanical units. When calculating how much work such microscopic systems can accomplish, quantum effects such as coherence and entanglement must be taken into account. Now, researchers have shown that systems in which quantum effects are pronounced can store more energy than systems that are purely classical.