IT’S a cardinal rule that heat flows from the hot end of an object to the cold, no matter which end you heat. But now researchers have suggested a way to build a device that conducts heat in only one direction. The idea has only been tested in a computer simulation, but if it works in practice it could lead to circuits that run on heat instead of electricity.
Heat makes molecules vibrate, and the jostling of molecules by their hot neighbours is what makes heat flow. This usually happens in any direction, but now Michel Peyrard of École Normale…
