Sample interview questions: Can you explain the concept of quantum electrodynamics and its role in understanding electromagnetic interactions between particles?
Sample answer:
Quantum electrodynamics (QED) is a quantum field theory that describes the interaction of light and matter at the subatomic level. It is one of the most successful theories in physics, having been experimentally verified to high precision.
QED starts with the idea that light is made up of particles called photons. Photons are massless and travel at the speed of light. They interact with charged particles, such as electrons and protons, by exchanging virtual photons. These virtual photons are not real photons, but they are allowed to exist for a short time by the uncertainty principle.
The exchange of virtual photons gives rise to electromagnetic forces. For example, the electric force between two electrons is caused by the exchange of virtual photons. The stronger the electric charge of a particle, the more strongly it interacts with light.
QED has been used to explain a wide variety … Read full answer