What Are Feynman's Insights on QED's Limitations in Nuclear Physics?

  • Context: Graduate 
  • Thread starter Thread starter Farn
  • Start date Start date
  • Tags Tags
    Feynman Mean
Click For Summary

Discussion Overview

The discussion centers on Richard Feynman's insights regarding the limitations of quantum electrodynamics (QED) in explaining certain aspects of nuclear physics. Participants explore the relationship between QED, quantum mechanics (QM), and quantum chromodynamics (QCD), as well as the broader implications of these theories in understanding fundamental forces.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant recalls Feynman suggesting that QED cannot explain nuclear physics, questioning whether he included quantum mechanics in that statement.
  • Another participant clarifies that QED is specifically a theory of electromagnetism, while QCD addresses the strong force that governs nuclear interactions.
  • A third participant notes that all quantum theories predict behavior but do not explain the underlying causes or nature of entities involved.
  • One participant references Feynman's assertion that the nature of magnetism remains unexplained, suggesting a broader limitation in the Standard Model.

Areas of Agreement / Disagreement

Participants express differing views on the limitations of QED in nuclear physics, with some emphasizing the need for QCD to address nuclear interactions. The discussion does not reach a consensus on whether Feynman included QM in his remarks about QED's limitations.

Contextual Notes

There are unresolved questions regarding the specific aspects of nuclear physics that QED cannot explain, as well as the implications of Feynman's views on the limitations of quantum theories and the Standard Model.

Farn
As I was recalling one of the Feynam lectures, I rememberd him saying that the only phenomena QED couldn't explain are the physics of the nucleus and one other that I can't remember...gravity maybe? Anyway, since QED deals with atomic particle interactions it was the nuclier one that surprised me. I sort of got the impression that he ment both QED and QM couldn't explain nuclier physics(but not sure if he was including QM).
So my questions are: Does anyone know what aspects of nuclier physics are not explainable with QED? AND, was he including QM when he said that?
 
Physics news on Phys.org
QED, quantum electrodynamics, is a quantum-mechanical theory of electromagnetism. You can think (loosely) of the following relationship:

quantum mechanics + classical electrodynamics = quantum electrodynamics

QCD, quantum chromodynamics, is a quantum-mechanical theory of the strong force, which is the force responsible for keeping protons and neutrons together in nuclei. QCD and QED are peers, one describing electromagnetism with quantum mechanics, and one describing the strong force with quantum mechanics.

There is currently no quantum-mechanical theory of gravity, though several approaches (loop quantum gravity and string theory) are being attempted simultaneously.

- Warren
 
Maybe it's because QED = Quantum electrodynamics refers to the EM force, and for nuclear effects you should be looking at QCD = Quantum Chromodynamics which deals with the strong nuclear force that is dominant in nuclear interactions?
 
All quantum theories are predictive theories that predict behaviour. They do not explain the cause of the action or what the entities are.
There is some difficulty with this because most books fail to point out the limitations of the Standard Model (quantum theories and relativity) but Scientific American recently did a special issue on this subject and the steps being taking to find the answers.
Feyman stated in one of his lectures that no one has explained what magnetism is and in his opinion no one ever would. This appears in one of the lectures in the three volume publication of his lectures. If you have access to a copy (I do not) look up the opening lecture on magnetism.
 
Last edited by a moderator:

Similar threads

  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
5K
Replies
10
Views
3K
Replies
12
Views
4K
  • · Replies 21 ·
Replies
21
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K