Category talk:Concepts in physics

What is fundamental?

What qualifies as a fundamental physics concept? I ask this because while I can see approximation being somewhat fundamental (and it is not in this category), it seems odd that spherical cows are considered fundamental (but is in this category). Should concepts be "fundamental" in the sense of being part of the foundations of physics, the sense of being introductory concepts that newcomers should hear of, or something else entirely? Saligron 23:47, 15 March 2007 (UTC)

Thanks for your question. I confess to adding most of the categories within the last few days. I had several discussions with colleagues on just what constitutes a fundamental physics concept. What we decided was that a fundamental physics concept was one that any physicist would need to be familiar with before embarking on a specialized experimental or theoretical track. By "familiar" we meant being able to solve problems at the end of the chapter on that topic. We did include various approximation methods (eg. perturbation theory, Hartree-Fock, etc.) but we did not include "approximation" itself. That seemed too general and amorphous. I am afraid we added the spherical cow reference as a bit of comedy that has made it into the physics culture and terminology (see references). We think all physicists shoud be familiar with the lesson of the spherical cow (One of the reasons that Heisenburg failed to develop a bomb, among others, was that he made his reactor spherical to make calculations easier). However, one may argue that the concept is more humorous than fundamental and I would not complain if a serious-minded person removed it.Complexica 17:57, 16 March 2007 (UTC)

Please take this conversation to Wikipedia talk:WikiProject Physics. I'm not feeling very charitable right now, so my gut impression is that this whole category should be nominated for deletion, precisely because the inclusion criteria are vague. All physics is fundamental, that's how we know its physics and not something else. Instead, if you wish, please devote your energies to Category:Introductory physics, which is what I think is what people were looking for. linas 20:36, 16 March 2007 (UTC)

Linas, I am sorry, but your response has irritated me. Why in the world would experts want to contribute to wikipedia if their contributions are sumararily dismissed. This category was populated by several experienced and working physicists and expresses their opinion on what is a fundamental knowledge base for the field. Introductory concepts are just that, those concepts that introduce you to the field. They are a subset of fundamental concepts.Complexica 14:50, 17 March 2007 (UTC)

Yes, they are a subset. But are they a proper subset? How do you decide that something is NOT fundamental? How about a few examples of physics articles which should NOT be in this category. JRSpriggs 11:09, 18 March 2007 (UTC)

An example of something that is a fundamental physics concept but is not an introductory concept is

• curved spacetime.

Examples of items that are not necessarily fundamental concepts are

• Laser - The concept of stimulated emission is included, which is the basic underlying concept of the laser, but the actual device built upon the concept is not included. Similarly for transistor.
• Physical astronomical or cosmological phenomena inferred from basic concepts are not included. These include Black Hole (although the underlying concept of singularity is included), neutron star, white dwarf, red giant, etc.
• Other applications of fundamental principles are not included, such as Tokamak physics, plasma waves (plasma (physics) is included), Alfven waves, sound waves (although the basic concept of waves is included), plasmons, phonons (although the basic concept of Bloch waves is included), antenna theory, radar, Larmor formula, synchotron radiation (although the more sweeping cerenkov radiation is included), x-ray, gamma ray, (these are specific types of electromagnetic radiation), and solar wind.
• Mathematical techniques such as partial differential equations, linear algebra, or calculus are not included, although the fundamental concepts of linearity and nonlinearity (superpositon) and curved spacetime are included.
• Computational techniques such as artificial viscosity are not included, although fundamental appoximation techniques such as perturbation theory are included.
• Derived theories such as Inhomogeneous electromagnetic wave equation that contain the same information as a more familiar presentation (Maxwell's equations) are not included unless they lead to a fundamental insight. An example of this is the reformulation of the source-free Maxwell's equations into the Electromagnetic wave equation leads to the identification of elecromagnetism with light.

The list of fundamental concepts is based roughly on the "Theoretical Minimum" of Lev Landau. Complexica 12:12, 18 March 2007 (UTC)

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