What is the difference between qcd and qed

It is a theory that describes the interactions of charged particles with electromagnetic fields. For example, it can describe the interactions between light and matter which has charged particles. Moreover, it describes the interactions between charged particles as well.

So, it is a relativistic theory. Besides, this theory has been considered as a successful physical theory since the magnetic moment of particles, such as muons, agree with this theory to nine digits. Basically, the exchange of photons acts as the force of the interaction because particles can change their speed and direction of movement when releasing or absorbing photons. Moreover, photons may be emitted as free photons which appear as light or another form of EMR — Electromagnetic radiation.

The interactions between charged particles occur in a series of steps with increasing complexity. That means; first, there is only one virtual unseen and undetectable photon, and then in a second-order process, there are two photons that involve in the interaction and so on. Here, the interactions occur via exchange of photons. QCD is quantum chromodynamics. It is a theory that describes the strong force a natural, fundamental interaction that occurs between subatomic particles. The theory was developed as an analogy for QED.

According to QED, electromagnetic interactions of charged particles occur via absorption or emission of photons, but with uncharged particles, it is not possible.

Primarily, QCD describes the interactions between quarks and gluons. There are two types of colour-neutral particles as baryons and mesons. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 2 years, 11 months ago. Active 2 years, 11 months ago. Viewed 2k times. Improve this question. Philipsmett Philipsmett 31 4 4 bronze badges. Add a comment. Active Oldest Votes.

Here's a Venn diagram to illustrate the relationships: By the way, the relationship between particles and fields is not always straightforward. Improve this answer. Chiral Anomaly Chiral Anomaly Maybe Feynman was referring to what I called "subtleties. But in most models like QED with non-zero charge , the relationship between them is more subtle at best, and often very complicated. Maybe that's what Feynman meant. The words are not always used consistently, and I don't know how Feynman preferred to use them.

Even discussions of the standard model talk about fundamental particles. Just because there is more precise language doesn't mean it is always useful. Featured on Meta. Now live: A fully responsive profile.