What makes something quantum? This question has kept a small but dedicated fraction of the world’s population – most of them quantum physicists – up at night for decades.
At very small scales, we know the universe is made up of waves and energy fields ruled by the laws of quantum mechanics, but at the scale of the everyday world around us we mostly see solid objects following the older rules of classical mechanics. When we ask what makes something quantum, we are asking where the line is between these two realms and how it can be drawn.
