Quantum Zeno Paradox

 

In the wonderful book Quantum Biology by Jim Al-Khalili and Johnjoe McFadden, they explain why on a microscopic level, the kettle that is watched will not boil. Zeno's paradox was the idea that if you try to catch someone by halving the distance to them in every move, you will never reach them because they will always remain half a move away. In the quantum world, it is slightly different. A watched particle retains its particle nature - you know where it is. When not watched, it also has a wave nature - a wave of probability. This means that there is a much wider space in which it might be. But by watching it, you collapse the wave function and make it stay in the same place. Hence on a quantum level, particles in my kettle would stay on the same level and not reach boiling point. The kettle is too big a system to apply this - it is an analogy - but I was amazed to discover that you can stop radioactive nuclei from decaying by watching them!