It’s a thermodynamic Houdini: the first material that appears to get colder as it heats up. Because of the unusual way the material interacts with infrared light, the finding, which appears October 21 in Physical Review X, could lead to camouflage against heat-sensing cameras and to efficient heating and cooling devices.
Physics textbooks explain that the hotter a body gets, the more light it radiates. This principle allows soldiers with infrared goggles to ferret out enemies even in total darkness.