Talk:Field (physics)
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Reviewing Cheatsheet
WikiProject Physics' Reviewing Cheatsheet (11:16, 8 July 2008 (UTC)) Do not remove the elements, but rather strike them as they becomes useless or irrelevant (i.e write
<s>text to be struck</s>) to indicate that this element was verified and found to be alright. Add/Expand
Categorize
Cleanup
Copyright Disambiguation
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Miscellaneous remarks
Edits to cheatsheet thru (at least) 07:44, 31 August 2010 (UTC)
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Missing stuff
[edit]what is missing here: field properties, e.g: homogeneous vs. nonhomogeneous, conservative vs. dissipative, central field, curl-field...
—Preceding unsigned comment added by 15:45, 27 August 2005 (talk • contribs) Icare
Don't we want all sorts of things in here, such as 4-Lagrangians, Lorentz covariance, tensor notation, Euler-Lagrange equations for a field, examples of Classical Electrodynamics, the metric as a potentials for gravitation etc? -Masud 17:18, 3 November 2005 (UTC)
(Re-org)
[edit]Heavily re-organised the page, and linked to classical field theory. -Masud 03:06, 29 November 2005 (UTC)
(Continuous random fields)
[edit]Added continuous random fields, because the relationship between quantum fields and continuous random fields is my research interest. It's possible to formulate quantum fluctuations in a continuous random field formalism, as well as and distinct from thermal fluctuations. The significance of such is TBD. What I've added to the Field (physics) page is probably not contentious, whereas my research is. Linking to details in other pages seems appropriate for a Field (physics) page, rather than the details of 4-Lagrangians etc. being here -PeterQ 14:44, 30 May 2006 (UTC)
- Dear Peter
- I have read your section on Continuos Fields, but I do not understand what you are talking about. Would you be so kind to provide context:
- what definition of random processes you are assuming
- how would this be different from anything we use in QM - we have random processes over space time all times (collapsing wave functions)
- how does temperature pops in???
- why do you say we assume two times differentiability? we do use distributions all times - even before Scwartz formalised them Dirac did so and before him Heaviside too..
- In summary: it is difficult to udnerstand what you haev got in mind!
- Thanks Peter
- Massimo Massimo.banfi (talk) 11:34, 10 May 2023 (UTC)
("Physical" link)
[edit]Quick note: the "physical" link in the first line goes to a disambiguation page in which there are no references to physics, the branch of science.
—Preceding unsigned comment added by 86.128.13.27 (talk) 16:35, 3 July 2007
Alert! Heavy Bias
[edit]This article is heavy biased towards the fields of high energy and elementary particle physics, and this problem must be corrected as soon as possible.
"In modern physics, the most often studied fields are those that model the four fundamental forces." -Actually, modern physics also includes quantum stat-mech, solid state physics, condensed matter physics, where fields that model things other than fundamental forces are common.
The only example of fields under classical fields are the elementary fields such as electromagnetic and gravitational. What about other classical fields that are ubiquitous in areas outside elementary physics, such as velocity, density, pressure fields in fluid dynamics?
The examples given under quantum fields are again, the elementary particle fields. What about the quantum fields used in condensed matter physics?
I am not an expert in any of these subjects, as I am myself a high energy particle physicist. If someone could rectify this problem, that would by much appreciated.
--TriTertButoxy (talk) 17:42, 12 January 2008 (UTC)
- No problemo,I agree with you. I fix that( you should have,too!). — Preceding unsigned comment added by 5.151.82.5 (talk) 23:45, 6 November 2012 (UTC)
Metaphysical statements are presented as statements of natural fact. Specifically that a field is a physical object. This is consistent throughout the article in a variety of guises. The best justification that is offered is that it has high descriptive utility. I don't see a place for personal or institutional philosophical prejudices & metaphysics in an article intending to describe a mathematical representation of a physical theory. No? 50.247.101.139 (talk) 03:53, 3 June 2015 (UTC)
Particle/field principle
[edit]I see in many articles the statement that there is a particle associated with a field, but this statement is non-obvious. I believe this article should explain this idea better. Is there a name for this principle? Is this particle/field mapping unique? If so, how can unified field theory be justified? 70.247.169.197 (talk) 18:10, 21 August 2010 (UTC)
Agreed. This is an attribute of the field of high energy particle physics, not fields in general. Particle physics content should go in particle physics articles, not in general physics articles. Reading this article one would leave with the belief that the only physics is particle physics. Considering how conceptually flawed & incomplete that enterprise is, it is not the appropriate means for conveying the ideas of physics in general. — Preceding unsigned comment added by 50.247.101.139 (talk) 04:00, 3 June 2015 (UTC)
About that cheatsheet
[edit] The "Reviewing Cheatsheet", now a box among the other headers in the lead section, started out as a full-width first section (before all the chronologically earlier discussion), apparently in conjunction with the accompanying article being designated as a WikiProject's article of the week (i.e., i presume, to encourage concerted effort upon it). That was via two edits on 8 July 2008; a single entry was actually ever made, a week shy of two months later (2008-09-01), to what apparently was an insertion of two versions of some boilerplate. Two more years (and one new comment) on it appears to me to have been mostly an intimidating obstruction.
I don't recall ever seeing anything to compare to it on any talk page, so it may either be a persistent peculiarity of the Physics WkProj, or have been a passing one. (The most recent physics article i recall editing, that even remotely approached the accompanying article in theoretical emphasis, was Diode bridge -- 14th and 18th edits to the page, in the first quarter of 2004! -- so how would i know....) But IMO, my taming it into a box among the other header boxes -- with "Skip to ToC" links available before and after reading the talk-page header -- should preserve its apparently small usefulness, without significant loss of ease of use, while making it easier to bypass.
--Jerzy•t 08:30, 31 August 2010 (UTC)
Illustrations
[edit]I added new illustrations also showing the direction of the field(s). I suppose this looks better, but I am open to suggestions. Is the relationship between direction and colour clear? Should I remove the "colour legend" (lower right corners) or add some arrows to it? Please let me know. I was honestly surprised to see the original greyscale illustrations survive for so long on multiple wikipedias. Vegard (talk) 18:20, 5 July 2012 (UTC)
- Thanks! The illustrations are colourful, but I'm sorry to say they didn't help me. I can see how intensity would map to magnitude, but my brain can't map hue to direction. Is blue up? Red down? Green left? What's right? Also there seems to be some artifact: the field should taper off smoothly, but it seems to have a hard edge to it. Sorry to be a wet blanket. I'm more of a "field of little arrows" person. Woz2 (talk) 11:43, 13 July 2012 (UTC)
- I'll try to explain it here, maybe we can work it into the image page or something. Do you see that circle in the lower right corner? That's the "legend" showing how colours map to directions; red maps to left, cyan maps to right, yellow/green maps to up, and purple/blue maps to down. So if you dropped a particle at any point which is mostly red, the particle would accelerate leftwards. For the first illustration (the one with two equally charged particles), there is a black part in the middle; if you dropped a particle exactly in the center there, it would stay perfectly still. If you dropped it slightly to the left or to the right, it would swerve to the center; if you dropped it slightly above or below, it would drift away from the center. About the hard edge, you are right: This is an artifact. The magnitude is capped at a threshold, i.e. you can't distinguish between two magnitudes above this threshold. The reason is simply that force is proportional with the square of the distance, so as you get closer to the center of the particle, the force quickly goes beyond what you can actually display on a screen. What I could try to do is to make those parts above the threshold fade to white, but then you'd lose some information about the direction again... I'll give it a shot and see if it's better. Thanks for the feedback! Vegard (talk) 09:44, 14 July 2012 (UTC)
- So I tried to use HSL instead, which first makes a transition from black -> fully saturated -> white: [1][2][3] (different strengths). I think it looks worse, because it's not actually clear, intuitively, what white represents (it actually represents "incredibly strong force") and it hides the direction of the field. It also actually doesn't help the problem with the artifacts, I just created another problem. So here's another one that shows the logarithmic magnitude: [4]. I think this is the only way to really get around the problem of displaying very strong forces, but the viewer has to keep in mind that intensity now corresponds to log-magnitude. Vegard (talk) 13:40, 14 July 2012 (UTC)
- I added some topographic lines (at exponentially increasing intervals) and quantised the colours: [5] Vegard (talk) 18:38, 14 July 2012 (UTC)
- I like the log version best. I didn't get what the inset was for: I would remove it and instead add words in the caption "hue represent the field direction: red means left, cyan means right, yellow/green means up, and purple/blue means down." Cheers! Woz2 (talk) 19:48, 14 July 2012 (UTC)
- Logarithmic magnitudes and contour lines. Better? Two positive charges. One positive and one negative charge. Vegard (talk) 19:29, 15 July 2012 (UTC)
- I like the log but I prefer them without the contour lines. My $0.02. Cheers! Woz2 (talk) 20:45, 15 July 2012 (UTC)
- Logarithmic magnitudes and contour lines. Better? Two positive charges. One positive and one negative charge. Vegard (talk) 19:29, 15 July 2012 (UTC)
More illustrations
[edit]Nice electric field images added by Vegard. Thanks!
If it's ok, I plan to add more field-line diagrams for other fields like classical and relativistic gravity, EM (including electric/magnetic monopoles), and quark-gluon fields for colour charge... Maschen (talk) 02:24, 27 August 2012 (UTC)
Static field
[edit]I removed the entire section; of the 4 references, none meets the reliability standard for a science article, and some of the (referenced) statements are outright false. — Arthur Rubin (talk) 05:41, 6 January 2013 (UTC)
plasma field interaction to create motion
[edit]with a simple glass plasma globe filled with various gasses,and the interaction with a non magnetic stainless steel mesh placed over said globe, the interaction with the vacuume of space can be observed.with the use of newer thyristor material ,general circuitry ,a second plasma field, a 1 to 1 induction transformation device and a coil of wire ,a varying field can be set up in said coil and the interaction with a magnetic field will result in the observable up and down motion of said coil. a source of negative ions needed to complete the one wire circuit from mesh on active plasma globe can easily be achieved by the interaction with you the observer , a wire to earth,ie. ground or another piece of non magnetic stainless steel. the plasma globe acting as a positive source of ions due to its attraction with the chromium/carbon content outside the vacume. you will find that all elements in the carbon group all hold interesting phenomenon, when interacting either with the initial plasma field or with other plasma fields and their various gasses initiated by their interaction with the primary plasma field.Ronald sykes (talk) 01:38, 22 July 2013 (UTC)
Can someone verify the basic supposition of this article, please?
[edit]I wonder at the presumption that (in physics) fields are "real", "occupy" space, and are measurable (ie physical quantities)? I thought there were a variety of fields which either are not (directly) measurable (ie QFT ψ) and/or do NOT "exist" in Newtonian 3-Space nor Minkowskian/Riemannian 4-space. Aren't there an enormous number of examples of fields in phase spaces which do not (directly) "exist" in "normal" space? Also (and excuse my ignorance) are spinors and tensors "measurable" physical quantities? (I thought they were more abstract objects than those we can physically "measure"). I'm not very knowledgeable here, but it seems to me that this article presupposes a certain set of classical and quantum fields as the ONLY ones to be included here, ignoring many others. Its also not clear to me why "real 'things'" are so emphasized here. I'd argue that most things of interest in science are abstractions rather than "real" objects (energy, entropy, time, space, conservation/symmetry as examples). I realize some of this has to do with ontology and what "real" or "physical" actually mean... But how can we claim "field X" is "real" when it be speculative (Supersymmetric extensions to the standard model, M-theory, ...)? Asserting the reality of an abstraction seems to me to be without much meaning. Surely no Classical 'field' is 'real' since its an approximation to the relativistic or quantum?Abitslow (talk) 21:06, 17 July 2014 (UTC)
- The lede here needs a lot of work. For one there needs to be a distinction between dynamical fundamental fields (like the EM field, quark/letpon fields, gauge fields etc.) on the one hand. Which (in some sense) are real objects. More real anyway than e.g. particles. And non-dynamical fields that merely describe physical quantities, like e.g. temperature or wind speed.TR 10:55, 18 July 2014 (UTC)
- Timothy: Good point. The weather forecast example in the first paragraph is mine, I was trying to give a more concrete example to follow on from the first sentence "A field is a physical quantity that has a value for each point in space and time." (Previously it just went straight into "A field can be classified as a scalar field..." which seemed completely offputting.) However, I think you're right - the rest of the article purely treats fields as carriers of interactions, but what the first sentence defines is really just a function of position and time. I agree with you that the lede needs work, and I think that (if nothing else) the example I wrote should be replaced with a better one - maybe the Earth's gravity? Having said all of that, I don't think this answers Abitslow's question! Djr32 (talk) 22:12, 19 July 2014 (UTC)
- I actually like your weather map example. It is something everybody can visualize and has seen. Moreover, it is a field. Fields like that are very common in physics.TR 18:38, 20 July 2014 (UTC)
- The basic presumptions are fine.
- The Earth's gravitational field is a description of how an object would be affected by gravity if it were placed somewhere near the Earth. It's a measurable thing, i.e. you could put a rock on a table in your house, or in an orbit 1000 km above the equator, and you could see how it is affected by gravity. On the other hand, you can't put an object in all possible places, and even if you could, they would be affected by each other as well... Even if our model of gravity is wrong (whether in the mathematical details - if it were to actually drop off faster than 1/r2 at large distances - or the whole picture - things fall to the ground because invisible pixies move them) the interaction still exists, and the concept of a "field" is still a useful one, it just means that our model of the field is wrong.
- I think you're wrong to get hung up on measurability here. (I was surprised to find that the article doesn't contain the word "measure", "measurement" or anything similar.) Tensors are certainly measurable things, e.g. the Cauchy stress tensor of a solid body is real and measurable in exactly the same sense that the pressure (a scalar quantity) is for a gas.
- Real things are important because the goal of physics is to describe the real world. Energy, entropy, time, ... are all real things (though they aren't "objects"). Models contain simplifications and abstractions, but ultimately the point of physics isn't the models, it's the reality that they are trying to model. Djr32 (talk) 23:00, 19 July 2014 (UTC)
What should content of the lead be?
[edit]IP person says it should be concise & neutral
The following content from this conversation was removed by IP: 74.95.15.9, see [6]. I am restoring it here because it prompted the conversation that follows. If the author of this content wishes to retract this, then the proper thing to do is to strike it through using this.
Measurability is not the issue. The issue is the unquestioned presumption hidden here: that fields are real physical objects. Usually this problem is in referring to EM or gravitational fields. This is quite different than the utility of fields in general as with the weather example. The bias systematically hides the underlying physical processes which it's utility is meant to represent, due to the conceptual picture it sells. "Fundamentally" fields are a book keeping tool for interactions of matter, nothing more. The mathematical utility of the field concept in the more general usage is confused with the conjecture in foundational physics. These problems seem to originate in quoting particular authorities in particle physics out of context. The principle defense appears to be "utility". The utility of the field relevant for this page is in quantifying interactions. The utility as a conceptual aid to putting forth a particular philosophy is not useful here. 2607:F140:6000:0:1140:E52C:9A9A:30EF (talk) 04:44, 3 June 2015 (UTC)
- Anonymous IP Person, please revert your deletions of material from this article. You have removed material that is interesting, useful, and which, in many cases, includes citations from notable physicists. You might, personally, disagree with some of the content, but that is not grounds for removing the material you have removed. I am notifying several editors of this on-going situation. @Maschen @Materialscientist @John Isambard Kingdom (talk) 23:48, 3 June 2015 (UTC)
- I'm happy to remove anything that is unreasonable, but you need to be more specific. These are cleanup edits, not personal disagreements or "mischief". This page is very much in need of cleanup: it is incomprehensible, inaccurate, & filled with philosophical bias. Evidently you prefer the stability of wrong, to moving toward something more sensible. What I've done is to remove a few of the controversial bits that were taken out of context, are outdated (by 50 years), or highly speculative & controversial. I am happy to discuss any specifics with editors of this page & help them to clean it up. However, randomly pulling in quotes from Feynman because they sound interesting & cool, is not my idea of responsible editing. Thanks for bringing this to talk, rather than rapid firing the undo as you were before, with little explanation or thoughtful analysis.
- If you like, feel free to start with the opening lines: "A field is a bookkeeping tool for accounting for the interactions of physical quantities. In more rigorous terms it is a mathematical representation of a physical quantity that can be represented as a function whose parameters include the position in space and the time instant (and possibly other parameters). " The purpose of the edit is to change the definition of a field to what it is in physics--see above, from what it is not--a physical object. It certainly is not an obvious "edifice" of the "foundations" of all of physics. 24.130.26.146 (talk) 01:36, 4 June 2015 (UTC)
- A productive way to proceed is to suggest text that represents an obvious improvement. So, your (seeming) assertion that fields are not real, but merely mathematical objects, should, in general, be cited. The article, as it stands, may not be supported by as much citation as is ideal, but we need to improve that. I can see that the article, as it stands, does make some confusing mix of discussion of "fields" that are real (under my interpretation), such fields that have energy, momentum, and which characterize the (very real) nature of electromagnetic radiation (are you suggesting that EM radiation is not "real"?). At other points the article is using the word "field" as, yes, a mathematical description, such as for weather maps. Our job here, is to improve the article in light of conventional interpretations. Isambard Kingdom (talk) 13:30, 4 June 2015 (UTC)
- No, I am not suggesting that radiation of any sort is not "real", radiation is real. You are confusing radiation with the concept of a field as a physical object. The problem with the article is not for lack of of citations. The problem is primarily that it doesn't make any sense, i.e. it is not conceptually consistent. A secondary problem is that it is filled with bias & interpretation. I am removing these, not adding to them. Finally, the root of these problems ( in my interpretation ), is that the solution to these problems appears to be that the editors of this page increase the number of citations & remove thoughtful work on it without themselves thinking about what they are doing. I'm not attempting to be mean, I'm explaining what I am seeing here--rapid fire undo based on argument from authority. — Preceding unsigned comment added by 2602:306:CE2F:6990:F418:DA9F:274B:4195 (talk) 21:28, 4 June 2015 (UTC)
- But the text you seem to want to remove uses the expression "physical entity" or "quantity", not "physical object". That seems to be a carefully chosen description: electromagnetic fields are "physical entities". At other place, yes, it says "physical object", so you might accept "physical entity" for those instances? Again, can you supply a draft paragraph that specifically addresses you concerns and which has citations to reliable sources? That would help, certainly, otherwise we will continue to go in circles, I'm afraid. Isambard Kingdom (talk) 21:53, 4 June 2015 (UTC)
- I added a citation to Feynman's lectures, and I've noted a quote from those lectures: "A “field” is any physical quantity which takes on different values at different points in space." Perhaps this is sufficient to address the IP's concerns. Isambard Kingdom (talk) 23:50, 4 June 2015 (UTC)
- I added a citation in the lead to an article entitled "The Origins of the Field Concept in Physics" by McMullin. Isambard Kingdom (talk) 14:13, 8 June 2015 (UTC)
- Feynman is not the end all be all, arbiter of truth, I'm sure he was wrong about plenty of important things. You clearly believe that it is self evident & obvious what a physical field is, no? If you wish to make a stronger statement, then the self evident & quite clear one you have removed 10 times, I believe you need to provide stronger support than a couple of self-evident-to-you citations.
- No, I am not suggesting that radiation of any sort is not "real", radiation is real. You are confusing radiation with the concept of a field as a physical object. The problem with the article is not for lack of of citations. The problem is primarily that it doesn't make any sense, i.e. it is not conceptually consistent. A secondary problem is that it is filled with bias & interpretation. I am removing these, not adding to them. Finally, the root of these problems ( in my interpretation ), is that the solution to these problems appears to be that the editors of this page increase the number of citations & remove thoughtful work on it without themselves thinking about what they are doing. I'm not attempting to be mean, I'm explaining what I am seeing here--rapid fire undo based on argument from authority. — Preceding unsigned comment added by 2602:306:CE2F:6990:F418:DA9F:274B:4195 (talk) 21:28, 4 June 2015 (UTC)
- Ok man, how about this: http://www.feynmanlectures.caltech.edu/II_15.html#Ch15-S4 What do you think? --Crosley 74.95.15.9 (talk) 04:01, 9 June 2015 (UTC)
- I'm sure that Feynman had a nuanced opinion about what is real, and what is not. The text you highlight demonstrates that. I am pretty sure, though, that he felt "fields" were just as real as "matter". I don't think this article needs to delve into such issues. The article does, however, need to summarize conventional interpretations (not yours, not mine) and cite authoritative sources. Feynman's definition of a field (in the physical sense) as "any physical quantity which takes on different values at different points in space" work just fine. The definition you seem to prefer is not yet backed up by any source, though it might be a suitable definition for an article that is more focussed on mathematics (but I am not sure). Isambard Kingdom (talk) 13:07, 7 June 2015 (UTC)
- "I don't think this article needs to delve into such issues." You state this, yet you consistently bias the content of the lead toward this position--field's are real. For example the last citation you added [1] reads as a treatise on this very view. Read the summary which states the purpose of the essay. To conclude the development of your fields are real argument you provide this citation [2] It's a nice & clear essay, I like his style. The field filling up the bathtub part clearly explains what you're getting at. It's also an ad for the anthropic principle. It goes in the QFT section. If you sincerely believe there is no need to delve into these issues, can we then agree to leave that particular philosophical position out of the lead & find some better place for it? --Crosley 74.95.15.9 (talk) 04:01, 9 June 2015 (UTC)
- I'm sure that Feynman had a nuanced opinion about what is real, and what is not. The text you highlight demonstrates that. I am pretty sure, though, that he felt "fields" were just as real as "matter". I don't think this article needs to delve into such issues. The article does, however, need to summarize conventional interpretations (not yours, not mine) and cite authoritative sources. Feynman's definition of a field (in the physical sense) as "any physical quantity which takes on different values at different points in space" work just fine. The definition you seem to prefer is not yet backed up by any source, though it might be a suitable definition for an article that is more focussed on mathematics (but I am not sure). Isambard Kingdom (talk) 13:07, 7 June 2015 (UTC)
- The first (referenced) sentence of the lead,
- In physics, a field is a physical quantity that has a value for each point in space and time.
- has been replaced by Crosleybendix with his own original research,
- In physics a field is a bookkeeping tool used to account for the interactions of physical quantities.
- Not only does this quaint sentence fail to give any indication of what a field is, but it offers a completely misleading analogy between the elementary discrete arithmetic used by bookkeepers and the mathematics of continuous fields. Accordingly, I have reverted the change. --Epipelagic (talk) 06:14, 8 June 2015 (UTC)
- I think your buddy Isambard at least shows some passion on the subject, & is therefore worth talking to. You, on the other hand come across as kinda douchee & out of your league. It's not clear where you are coming from, or if you have any knowledge on this subject whatsoever. If you had the slightest clue, you'd know exactly what I was saying--it's all right there after all--& you would form a constructive thoughtful reply of how to do it better. I suspect it's not the bookkeeping part that evokes this provocative word "quaint", but rather that you are a snooty sort with little to contribute, as you have thus so demonstrated. I could be wrong, but if you've got nothing to say, in my humble opinion, chiming in on the noise is less than helpful.2601:9:4501:B400:5400:A9D2:D99:F6D3 (talk) 00:31, 9 June 2015 (UTC)
- You are welcome to your "humble" if confused opinions, even though they appear confined to projections. However, continuing to post as a sock while blocked is not an acceptable practice on Wikipedia. John appears keen to encourage you on these issues, so I suggest you engage him rather than waste the time of other editors. --Epipelagic (talk) 08:58, 9 June 2015 (UTC)
- I think your buddy Isambard at least shows some passion on the subject, & is therefore worth talking to. You, on the other hand come across as kinda douchee & out of your league. It's not clear where you are coming from, or if you have any knowledge on this subject whatsoever. If you had the slightest clue, you'd know exactly what I was saying--it's all right there after all--& you would form a constructive thoughtful reply of how to do it better. I suspect it's not the bookkeeping part that evokes this provocative word "quaint", but rather that you are a snooty sort with little to contribute, as you have thus so demonstrated. I could be wrong, but if you've got nothing to say, in my humble opinion, chiming in on the noise is less than helpful.2601:9:4501:B400:5400:A9D2:D99:F6D3 (talk) 00:31, 9 June 2015 (UTC)
Has anyone reviewed this lead recently? It’s quite confusing and actually wrong about the subject. I just reviewed the edit war from 8 years ago where some editors seem to have quashed attempts to clarify things. Xp fun (talk) 11:52, 20 March 2024 (UTC)
Some loose ends
[edit]In my opinion, the article (and the lead) need to
1. Discuss divergence-free (solenoidal) fields, such as magnetic fields, and fields that have divergence, such as electric fields related to charges. 2. Need more discussion of spinor and tensor field types. 3. The lead needs better connected discussion of electromagnetic fields and light. 4. Continue adding citations to authoritative (and available) reference material.
Other editors might identify additional shortcomings of this article ... Isambard Kingdom (talk) 13:20, 8 June 2015 (UTC)
- Fine, but why does all of this stuff need to go into the lead? 74.95.15.9 (talk) 03:41, 9 June 2015 (UTC)
- Both the lead and the main part of the article need work. Isambard Kingdom (talk) 09:28, 9 June 2015 (UTC)
- Perhaps a clarification of the way tensors generalise the classical field. And more indication of the wide occurrence of fields in the physical world. For example, the wide application of stress–energy tensor fields. Or various applications of the Ising model of ferromagnetism, which can describe many areas other than ferromagnetism, even emergent behaviour in biological swarms. --Epipelagic (talk) 09:48, 11 June 2015 (UTC)
- And I would even interested in possible discussion in the article as to whether or not fields can be "physical quantities". We just need some citations to reliable sources for that!
- Also some discussion about what different field properties mean physically: 1. Divergence = source/sink (charge). 2. Potential field = no work closed path. 3. Poloidal+Toroidal decomposition for divergence free-fields, and general discussion about turning vector fields into sets of scalar fields (e.g. poloidal and toroidal scalar functions). -- added by Isambard Kingdom (talk) 21:13, 11 June 2015 (UTC)
- I would avoid getting entangled in confusions about whether fields in themselves are physically real or not. That seems like a throwback to the aether theory. If a classical field is used to accurately model or describe physical quantities in the real world, such as stress and deformation in the earth's crust, then that is certainly something real in the sense that the quantities being modelled can be sampled and checked in the real world. But the field in itself is an abstract mathematical construct, a mere description, and remains just that, regardless of whether or not it is used to accurately describe physical quantities. Quantum physics has separate issues to do with what can said to exist when location itself becomes ambiguous. But those issues belong more properly to quantum physics than to field theory as such. This article is just a summary overview of fields, and should concentrate on presenting the different types of fields, how they relate to each other, and how they can be applied to the real world. --Epipelagic (talk) 15:09, 12 June 2015 (UTC)
- Okay, I understand. While I've occasionally used the word "real", in some this communication on the subject, I've come to realize that the issue of importance (as discussed by Feynman and others) is whether or not a field is a "physical quantity" (the first sentence in the lead of this article). For most practically minded people, if something can be measured (as giving a force, having momentum, etc.) then that something can be "quantified" and it is, therefore, a "quantity". Indeed, understanding things we can measure is a basic focus of physics. Those are my feelings too. I'm just saying that if there is some cited material that this is not a reasonable way of looking at things, then let's see it! I haven't seen it. Isambard Kingdom (talk) 15:44, 12 June 2015 (UTC)
- Crosleybendix has been blocked indefinitely on the grounds that he was "not here to build an encyclopedia". I'm not sure that's altogether true, though he was clearly going to be hard work. It seems he was really blocked because he was rude to an administrator. I gather the gist of his position was that there should be something in the article about the implication of the Aharonov–Bohm effect on the physicality of the electromagnetic potentials, Φ and A, in quantum mechanics. Note Lev Vaidman recently challenged this interpretation by showing the effect can be explained without the use of potentials so long as one gives a full quantum mechanical treatment to the source charges. See also: [7], [8] and [9]. Since this seems to somewhat settle the matter, perhaps a brief section on the physicality of fields might be appropriate after all? --Epipelagic (talk) 22:17, 12 June 2015 (UTC)
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"Static field" listed at Redirects for discussion
[edit]A discussion is taking place to address the redirect Static field. The discussion will occur at Wikipedia:Redirects for discussion/Log/2021 June 17#Static field until a consensus is reached, and readers of this page are welcome to contribute to the discussion. Hildeoc (talk) 11:12, 17 June 2021 (UTC)