# Chapter 9. Quantum mechanics

## SUMMARY

In QFT the paradoxes of QM have simple answers:

- There is no wave-particle duality because there are no particles. The particle-like behavior is explained by the fact that field quanta live and die as a unit. This phenomenon is called quantum collapse.
- The Uncertainty Principle is simply a statement that fields cannot be localized; they spread out.
- There is no role of the observer. Quantum collapse happens whether or not someone is looking.
- Entanglement is a more elaborate example of quantum collapse that occurs when two quanta are created together.

Is that all there is to it? Did I give too little space to discussing these “profound” paradoxes? Well, that’s really all there is to it. In QFT everything is fields. They spread out, they collapse, and they do all this without requiring an observer. When I hear people complaining about the weirdness and inaccessibility of modern physics, I want to ask, “What part of Quantum Field Theory don’t you understand?”