# Physics subfield tags and general tag rules

Since we have a fairly broad definition for what is allowed for discussion, we'll probably end up with a number of variations on the standard physics subfield tags. What are some general rules we should devise for managing these tags?

i.e. particle-physics or just particle with physics being redundant? I've added tags with particle-physics and high-energy-physics so far. I think it's more clear to have the -physics, even though it may be redundant.

I see a tag for definition already on the front page. Valid? I tend to think not... though an argument could be made for looking up all the definition posts we'll eventually have.

• I added the tag for definition. My reasoning was that in the future, people might come to the site with questions such as "What is spin?" and then search for a definition of the topic in the search bar(i.e. spin definition). In that case, the question in which spin gets defined would hopefully be close to the top of the results, if not at the very top, if it had the definition tag associated with it. Furthermore, if I went into tags, I could click on the definition tag and come up with a glossary of physics definitions on the site without having to type anything. – Mana Nov 2 '10 at 20:34
• +1 for the question. I also agree with the tag definition. But for physics fields, we should have a definite nomenclature. – Cedric H. Nov 2 '10 at 20:58

I thought it might be useful, at least at the beginning of the site, to make a list of some canonical forms of subfield tags. Obviously it's impossible to create a comprehensive list of tags, but my idea is to have a set such that any question which is appropriate for the site could be tagged with at least one tag from the set. This will also help us out later when people get enough rep to vote on tag synonyms, since we'll already know what the community thinks the canonical forms of certain tags should be.

To begin with, these tags are already used on the site and I think they would make good subject tags:

• acoustics
• astrophysics
• atmospheric-science (physical aspects of meteorology and climatology)
• classical-mechanics (when lagrangian-mechanics and hamiltonian-mechanics and newtonian-mechanics are too specific)
• cosmology
• education (could be renamed to physics-education)
• electro-magnetism (needs to have the hyphen removed though)
• fluid-dynamics
• general-relativity
• geophysics (physical aspects of geology and seismology)
• gravity (when general-relativity and newtonian-gravity are too specific)
• hamiltonian-mechanics
• high-energy-physics
• kinematics (basic relationships between position, velocity, and acceleration)
• lagrangian-mechanics
• magnetohydrodynamics
• mathematical-physics
• medical-physics
• newtonian-mechanics
• nuclear-physics
• optics (when quantum-optics is either too specific or inappropriate)
• particle-physics (although this might fit under high-energy-physics)
• physical-chemistry
• quantum-field-theory
• quantum-mechanics
• quantum-optics
• rotational-dynamics
• special-relativity
• string-theory (also might fit under high-energy-physics)
• thermodynamics
• wave-theory

These have not been used on the site, but I think they would be appropriate subject tags:

• atomic-physics
• computational-physics
• condensed-matter-physics
• newtonian-gravity

The tags in the following list are in use, and I can see how they could be good subject tags, but I think they're either too broad or too specific, or redundant with the preceding lists. Note that I am not advocating that these tags be renamed or deleted. They're fine as tags (well most of them are fine), but I just think that any question that uses them still should have a tag from one of the previous lists. Others may disagree.

• mechanics: too broad
• climate-science: subset of atmospheric-science
• applied-physics: too broad
• experimental-physics: too broad
• standard-model: subset of high-energy-physics
• aerodynamics: subset of fluid-dynamics
• sound: typically equivalent to acoustics
• philosophy: probably off-topic, or there should be another applicable tag
• large-hadron-collider: subset of high-energy-physics
• accelerator-physics: subset of high-energy-physics
• software: equivalent to computational-physics
• nuclear-engineering: equivalent to nuclear-physics
• material-science: either equivalent to condensed-matter-physics, or the question may be off topic for this site
• electrostatics: subset of electromagnetism

Comments and suggestions are welcome and encouraged. I'm making this CW so it can be collaboratively edited (although if you change something other than fixing a typo, please leave a comment).

Another related question: what should we do with tags like elevator or such things. Should poeple able to edit tags try to retag question with a tag that is an actual physics field ?

• What tag would you add to a question with the elevator tag? mechanics? – Nick Nov 5 '10 at 18:06
• Yes why not. I mean the goal of tags is to give the possibility to "filter" questions. "elevator" is not really a keyword in physics. – Cedric H. Nov 5 '10 at 23:07

Have you considered using arxiv style tags? It's being used on both MathOverflow and CSTheory, and seems to make a lot of sense.

• We can definitely use them, but personally I'd prefer the spelled-out field name as the main tag and the arxiv tag as tag-synonym – Tobias Kienzler Nov 5 '10 at 6:40
• It makes sense if the target audience all knows the arXiv convention, i.e. the researchers. But this site does not seem to be heading in this direction (research-based), so arXiv-style tag will just make the tag system harder to follow. This has been heavily discussed on math.SE before, BTW. – kennytm Nov 5 '10 at 8:18
• @KennyTM: Yes, but Tobias Kienzler's idea still works . – Abhimanyu Pallavi Sudhir Aug 10 '13 at 18:04