Quantum Electrodynamics
Developed in the 1920s by a group of physicists, quantum electrodynamics is the quantum field theory that is employed for electrodynamics. Its general purpose is to describe how matter and light interact with each other. Physicists are able to mathematically describe all different types of phenomena that involve the electrically charged particles that are interacting by exchanging photons. Because quantum electrodynamics has been known to provide tremendously accurate predictions – especially in cases of the anomalous magnetic moment of the electron – that one physicist referred to quantum electrodynamics as the "the jewel of physics."
History of Quantum Electrodynamics
In 1927, the research in the quantum field began to change from an understanding on individual particles to waves. This brought about a total change in how research was conducted. While there were early contributors of the work – Dirac, Wolfgang Pali, Weisskopf and Jordan – the true research did not culminate until the 1940s. Richard Feynman, Freeman Dyson, Julian Schwinger and Sin-Itiro Tomonaga put together the modern day understanding of quantum electrodynamics. They won the Nobel Prize in 1965.
Physical Understanding of Quantum Electrodynamics
What quantum electrodynamics does is describe, physically, what is going on with the charged particles and antiparticles in regard to their interactions with each other. When they are interacting, what can be observed is the exchange of photons from one to the other. The magnitudes of these interactions are then computer; however, because QED cannot offer exact answers, but instead, near exact predictions, each magnitude is given a probability. This means that QED determines the probability that one specific magnitude has a specific probability. Then a researcher is able to determine experimentally which is going to happen most likely.
In layman's terms, QED does not predict what is going to happen. However, what it does predict is the probability that something will happen. What are the chances that a particular magnitude is the one that will be exhibited? Because the QED results match experiments to such a high degree of accuracy (10-12), it has been considered one of the most accurate physical theories ever created.
Feynman's Three Basic QED Components
Feynman was one of the lead researchers are creators of QED. He wrote a book about QED is the average individual to understand called QED: The Strange Theory of Light and Matter. In it, he set out three basic components of QED. They are:
- A photon goes from one place to another place from one time to another time.
- An electron does the exact same thing, going from one to another place and from one time to another time.
- The electron either emits a photon or absorbs it a particular place and time.
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