Probably a stupid question, but will we ever have something like a microwave to make things cold? Is there a reason this can't exist?
(lemmy.dbzer0.com)
You can dump energy into something by blasting photons at it, because photons carry energy. You can't do the reverse because you'd need to use particles with negative energy. Either that, or you'd need to suck photons out of the food, but it doesn't work that way; things radiate photons at a specific frequency and intensity (called blackbody radiation) depending on how hot they are, and you can't make them emit more energy except by getting them hotter.