How do you cool radio waves? Do waves have a temperature in the first place? Common waves are hot meaning they are noisy. There are multiple sources of noise in the generation process of waves and some of them are related to temperature. One of these sources, and probably the most difficult to remove, comes from the intrinsic random motion of atoms.
A possible solution would be to conventionally cool down the antennas that emit the waves. But even at temperatures of miliKelvin, the jiggling of atoms produce a significant amount of noise.
A group of researchers at TuDelft led by Prof. Gary Steel have managed to cool radio waves to their quantum ground state and the process is as surprising as it is difficult to grasp. They’ve placed a circuit close to the antenna that gets coupled to it via its magnetic field. This circuit then acts as a “vaccum cleaner” that absorbs entropy from the antenna cooling it down.
This cooling process and subsequent noise reduction, published in Science Advances, will be of the utmost importance in detectors in a wide range of devices and purposes: from NMR to astronomical detectors.
We made this animation with the help of Dr. Ines Rodrigues (first author of the paper) and Prof. Gary Steele to illustrate the process.