To evade friction, try taking a quantum shortcut.
Two teams of physicists are building tiny machines designed to operate with the maximum possible efficiency. According to thermodynamics, there’s an ultimate limit to the efficiency of machines known as heat engines—including steam engines and car engines—which convert heat into motion or other types of energy. But real-world engines never reach that maximum efficiency, and often run well below it, because they lose energy to friction.
Now, quantum experiments are circumventing the limitations imposed by friction using specially designed shortcuts.