Talk:Phase transition

message: I noticed the phase transition is described with latent heat (under Modern classification) and as in which derivative a discontinuity is found.
In my opinion, first or higher order phase transitions are most easily understood mathematically by looking at it from a Landau theory point of view. One could describe the phase transition as such, that in a first order phase transition the stable state is the disordered one (order parameter = 0) at high temperature. As the temperature decreases, a metastable is formed which corresponds to an ordered state. As temperature decreases more, the ordered state order parameter can increase even further. At the critical temperature, the free energy of the metastable ordered state is equal to that of the disordered state, after which the ordered state becomes the stable state if temperature decreases further. At the critical temperature, a discontinuous jump in order parameter (of which the physical interpretation is the phase) occurs.
For a continuous (second order or higher) phase transition, the ordered state also is stable from a certain temperature downwards, but this state will grow more ordered from the disordered state as temperature is decreased. So instead of a jump, the order parameter of a stable state continuously grows from zero.
Perhaps a connection to Landau theory in this section is wise as well. And a graph of the order parameter versus the temperature, where the metastable state can be drawn in a dotted line for the first order phase transition.
Hopefully I explained it well enough for you to understand what i want to add. Please consider that this is my first addition to wikipedia, meaning feedback is very much welcome but let it be constructive.
LotteUU (talk) 11:26, 16 November 2021 (UTC)
thread_title:  More strictly defining the relation between the order or a phase transition and the order parameter of the stable state under Ehrenfest classification 

message: From the sentence "A phase of a thermodynamic system and the states of matter have uniform physical properties, because of their different mass."
I don't understand the part "because of their different mass", and I'm pretty sure it's wrong.  I would just remove it, but I wanted to see if anyone objects. Muaddib131 (talk) 16:34, 4 August 2014 (UTC)
thread_title:  "because of their different mass" in opening paragraph 

message: Is there no literature on whether the temperature of a phase change for a particular element or compound can be predicted from current physics (i.e. quantuum mechanics)?
Does current physics explain why mercury is a liquid in its "normal" state but Oxygen is a gas in its "normal" state?
Should the success or failure of physics to be able to predict such a thing be part of this article?
69.250.30.203 (talk) 18:04, 16 January 2010 (UTC)
thread_title:  Prediction of temperature of phase change 

message: It would be nice to include sample (possibly schematic) phase diagrams for a few typical systems, e.g. water (P vs. T), a ferromagnet (H vs. T), and superconductivity (H vs. T).  The same diagrams should be included on the respective pages, and perhaps discussed in more detail there.  Steven G. Johnson 21:28, 24 Mar 2004 (UTC)
thread_title: Diagrams

message: The article represents third and higher order phase transitions as a theoretical possibility. Have they actually been observed in practice? --137.111.13.34 22:47, 14 Oct 2004 (UTC)
thread_title:  Higher-order phase transitions 

message: Most people probably think of the liquid/gas system as having a first order phase transition. I think a couple of extra sentences could help explain what is continuous in this system. Ie the change in density across the phase coexistance line as a function of (T-Tc). Although I'm not confident enough that I won't make it worse to clarify this myself.
:Er, it is a first-order transition (except at the critical point). -- CYD
It is not first-order past the critical point. Itamblyn (talk) 13:58, 17 June 2009 (UTC)
thread_title:  liquid/gas possible confusion 

message: Why were the references and some of the interwiki links removed? I'm restoring them, but if there is a good reason to remove them, let me know. Salsb 17:56, 22 September 2005 (UTC)
thread_title: Removal of references and links 

message: The article on phase change should be merged into this one since it addresses a small subset of phase transitions — those between solid, liquid and gas.  Those issues can be perfectly well discussed in the introductory material to the present article.
The section of phase change on the technology behind DVD and CD writers should be given its own article, and phase change should simply become a redirect to phase transition.
Once this is done, I propose that :Category:Phase changes be renamed to :Category:Phase transition.
Thoughts? — WebDrake 00:43, 19 October 2005 (UTC)
replies: text: Category:Phase transitions probably? Agree with all the rest. --ACrush ?!/© 10:49, 19 October 2005 (UTC)
thread_title:  Propose to merge [[Phase change]] into the present article 

message: The following paragraph appears:
"The presence of symmetry-breaking (or nonbreaking) is important to the behavior of phase transitions. It was pointed out by Landau that, given any state of a system, one may unequivocally say whether or not it possesses a given symmetry. Therefore, it cannot be possible to analytically deform a state in one phase into a phase possessing a different symmetry. This means, for example, that it is impossible for the solid-liquid phase boundary to end in a critical point like the liquid-gas boundary. However, symmetry-breaking transitions can still be either first- or second-order."
I can't make sense of it.  While this could certainly be my mistake, I think it could be made clearer.  Could someone look it over and make sure the wording is as clear as possible?  Thanks.  207.157.43.71 14:06, 18 July 2006 (UTC)
thread_title: Question:

message: Hello physicists,  I was trying to learn about order parameters, which i get the vague notion sort of describe something about how something changes during a phase transition. great!!  but -- the page for Order Parameters redirects to this page, and this page says "... order parameters, which we will describe later ..."  lies! there are no later descriptions!  silly physicists... now i still don't understand order parameters.
:Have you read Landau theory on second order phase transitions? TomyDuby (talk) 01:57, 14 July 2008 (UTC)
thread_title:  Order Parameters 

message: The article lists the change from liquid to gas as boiling/evaporation. Surely evaporation is the change from liquid to vapour, not gas. That's why it is called eVAPORation. 86.133.202.12 20:53, 12 May 2007 (UTC)
replies: text: I assumed vapor and gas were interchangeable, apparently not.  After a quick skim of their articles, it seems like the term is used correctly, although it could perhaps have been named more sensibly in the first place.Bistromathic 15:27, 20 May 2007 (UTC)

text: boiling is the phenomena where a gas phase forms within the bulk liquid phase.  It takes a little more energy to nucleate (start) a bubble than it does to evaporate an equal amount of liquid at an existing gas-liquid interface.  Boiling requires that the liquid be superheated.  —Preceding unsigned comment added by Pvkeller (talk • contribs) 15:58, 4 December 2008 (UTC)
thread_title:  Evaporation 

message: Could anyone explain in more detail the difference between the two classification systems?  I assume they are equivalent in most cases, is this true?  Is the Ehrenfest system actually disused?  This system was taught to me in a recent lecture, albeit by a rather hopeless lecturer...  He also kept going on about  Lambda Transitions, which do not seem to be as important as the impression he gave, as they are not mentioned in this article (please ignore me if I have had a bout of stupidity and / or blindness and missed it).Bistromathic 15:32, 20 May 2007 (UTC)
thread_title:  Ehrenfest classification system 

message: The first diagram showing the phase changes indicates that "Sublimination" is a phase change. The term is in fact--as the table later shows--"sublimation." "Sublimination" isn't related to physics--it might be a paranormal term but it's definitely wrong here.66.174.92.168 04:06, 25 July 2007 (UTC)
thread_title:  Diagram Labeling Error 

message: The phase diagram shown in the article has a small error, but I am no good at editing images so I was hoping I could raise the awareness and someone might fix it up.  The dotted line showing the phase transition from solid to liquid for water is drawn in as a very curvy line.  In every phase diagram of water I have ever seen it looks more like a straight line with more of an obviouse 'negative' slope.  The line stays straight at least until 200+ atmospheres of pressure.  Also, where the dotted line first branches out from the solid line at first it appears to have a slightly positive slope, and this is definately incorrect...Thanks, and comments much appreciated. CoolMike 00:51, 2 August 2007 (UTC)
thread_title:  Phase Diagram 

message: This article seems to deal primarily with discontinous/first order phase transitions. E.g. "The order parameter is the quantity which is indeterminate at the critical point" this is true for a discontinous phase transition but not for a continous/second order phase transition. /Lokal_Profil 12:43, 3 March 2008 (UTC)
thread_title:  Discontinous phase transitions 

message: The article says: "The second class of phase transitions are the continuous phase transitions, also called second-order phase transitions." Two paragraphs later: "Several transitions are known as the infinite-order phase transitions". Can I from this deduce that infinite order phase transitions are second order phase transitions?
I think that this needs clarification.
TomyDuby (talk) 03:23, 17 October 2008 (UTC)
thread_title:  Second class of phase transitions -- there is some confusion 

message: I made an edit earlier that was promptly reversed by adding /Fusion next to Melting in the phase change table. I believe these terms are synonymous and it should be reflected in the article.
Reference:
Chang, R., Chemistry, 7th Ed, McGraw-Hill (2002)
I've also seen this my physics and physical chemistry text books as well as online dictionaries.
Jaa6c6 (talk) 22:47, 9 November 2008 (UTC)
replies: text: Thanks for citing a reference; I will unrevert the change. Here on Wikipedia, we are really sensitive to information that seems like it is just randomly entered. -- penubag  (talk) 22:57, 9 November 2008 (UTC)

text: As a linguistic activist, I must say that I think a more proper use of the word fusion (with respect to melting) comes from the Oxford English Dictionary: "fusion, n. 3.a. The union or blending together of different things (whether material or immaterial) as if by melting, so as to form one whole; the result or state of being so blended."  This use the term "fusion" is related to but distinct from the term "melting".  This definition expresses the idea "fusing-by-melting" or "melt-fusion".  Using the word "fusion" as a synonym for "melting" itself is potentially confusing because fusion seems to relate more to the process of freezing, where molecules fuse together to form rigid structures. --Zeroparallax (talk) 05:41, 10 August 2012 (UTC)
thread_title:  Melting and fusion are synonymous 

message: This is a minor but common point: phase transition or phase-transition; phase change or phase-change ? I see that both forms are used in the article at the moment; maybe one should fix one form according to the style of wikipedia. --PMajer (talk) 12:39, 4 December 2008 (UTC)
thread_title:  Dash? 

message: In the table of transitions plasma is reached only from gas/fluid. But this is not so obvious from the P-T diagram - there it seems that if P is high enough maybe solid-to-plasma transition can occur. It is not very clear, because plasma is not shown on the P-T diagram. So, we should eighter mention solid-to-plasma or change the P-T diagram so that it shows a negative slope on the solid/liquid line after some point so that there is no solid-to-plasma. In eighter case the plasma phase should be added to the P-T diagram. Alinor (talk) 17:49, 4 October 2009 (UTC)
thread_title:  solid to plasma transition 

message: Dear Friends,
I found a line saying one of the earlier attempts to formulate a scientific law of phase transitions was by Engels. I thought it was irrelevant and deleted it promptly.  —Preceding unsigned comment added by Pteradactyle (talk • contribs) 22:50, 4 December 2009 (UTC)
thread_title:  Where does Engels come into this??? 

message: about Mistake - is liquid/gas first or second order?
The article says the liquid/gas transition is first order, but then later says it has the same critical exponents as the uniaxial (a term which is not explained) ferromagnet, which is second order. The comment "Mistake" above makes a related point. Paulhummerman (talk) 10:59, 23 September 2010 (UTC)
replies: text: The ferromagnetic phase transition between magnetic moment up and magnetic moment down is a first order transition. The transition line lies at external field h=0. But for increasing temperatures, this transition line ends in a critical point, beyond which only one phase, the paramagnetic phase, exists. The same is true for liquid-gas transition. At lower temperatures, the phase transition is first order, but for increasing temperatures it ends in a critical point, above which neither gas not liquid exists, but just single homogeneous phase (you may want to have a look at the phase diagram of water to better understand what I am saying). This brings with it the interesting consequence that liquid and gas are only distinguishable in pactice, not in principle. Alas, this is a source of a lot of problems in describing what seems to be an everyday phenomenon; and I've not seen a good physical explanation, yet. Most things I've seen mix up the transition between liquid and gas and the transition between "liquid and gas can exist" and "only one phase can exist" in an erroneous manner (for instance, this very article says that "The order parameter is normally a quantity which is 0 in one phase (usually above the critical point), and non-zero in the other. [...] For liquid/gas transitions, the order parameter is the density.", which is clearly self-contradictory).  --timo (talk) 21:50, 26 May 2011 (UTC)
thread_title:  About "Mistake" - order of liquid/gas transition 

message: Hello, I'm not well versed on the propper form of Wikipedia editing so if I'm doing something wrong I apologize in advance.
What I wanted to discuss is that this article on phase transitions isn't general enough to describe what phase transitions actually are. It states in the opening statement that "A phase transition is the transformation of a thermodynamic system from one phase or state of matter to another." and this is merely one of the many kinds of phase transitions there are. A phase transition is the physical process through which a system (thermodynamical, classical, quantum...) undergoes a discontinuous behavioral shift. Condensed Matter physics is ripe with examples of this: not only the thermodynamical "matter phase transitions" but Bose-Einstein condensation (fluid-superfluid transition) or Superconductivity which can actually be seen as a change in the nature of matter (from fermionic to bosonic!) and other fields of Physics deal with phase transitions. As another example, the Higgs mechanism implies a phase transition on the Standard Model, and most inflationary processes in Cosmology are models that create a phase transition in the early Universe.
It is my belief that presenting phase transitions as a purely thermodynamical mechanism is misleading and detracts from their position as one of the most important mechanisms to understanding the natural world. The Wikipedia article on Landau Theory is a great place to start for those whose interest is picked. My suggestion is that a tag is added to the article saying it needs to be generalized so it will hopefully garner the attention of an expert (the current incarnation of the article could be the "Thermodynamical Phase Transitions" Section). I might even help out if needed (the field is so incredibly vast that rewriting this article in those lines is a very, very daunting task).
And in case you're wondering, no, I'm not a phase transition academic that wants to see my field of work get more recognition :) I'm just a Physics grad student that has been marvelled by the subject ^^
Capelo (talk) 17:49, 20 January 2011 (UTC)
thread_title:  Lack of Generality of the Article 

message: The article (or someone here) should answer these questions: In the modern classification scheme, are there solid rules for defining the transition categories, or is it more like a loose collection of similar phenomena (like classification in biology)?  Is there an easy way to define infinite-order phase transitions other than saying "They are continuous but break no symmetries."?  (And do the other continuous transitions always break symmetries?)  Also, if the second-order transitions are characterized by divergences, do infinite-order transitions lack such divergences?  --Zeroparallax (talk) 06:02, 10 August 2012 (UTC)
thread_title:  Modern Classification 

message: Right now we just have a gas/liquid/solid phase phase diagram in pressure temperature. Since plasma seems to be singled out as "the fourth phase", it would be nice to also add on the plasma phase to the P-T diagram, although I'm not sure what the generic form of this is. For example, I suppose that upon heating a molecular substance it first decomposes into a polyatomic gas, and then finally begins to ionize. To avoid that extra intermediate phase we could consider a more simple specie, perhaps cesium. 
It sounds like some such experiments have been done with cesium. This paper offers some insights however the diagram is not quite what we want (pressure-volume or axes instead of pressure-temperature). A few key things we can note:
* The transition to plasma seems to be gradual as temperature is increased. The parameter alpha only varies gradually. This seems to indicate that it is not really a proper phase transition, but rather more resembles the gradual transition from liquid to supercritical fluid. Possibly it could also be a second order phase transition. If so, it is not clear to me where the critical point of the gas-plasma transition is.
There is also this diagram (similar axes) which says that many of the very high temperature phase transitions are only continuous transitions... --Nanite (talk) 07:44, 19 February 2014 (UTC)
thread_title:  plasma phase transition on phase diagram 

message: Stars are plasma, gas giants are gas, rocky planets have liquids/solids. The relevance of phase transitions in cosmology is in the stars/planets themselves. The symmetry breaking stuff sounds like a mathematician went crazy. Wavyinfinity (talk) 12:26, 11 November 2014 (UTC)
thread_title:  Relevance to Exoplanets/Stars 

message: How is this even logically possible? - needs to be rewritten.
"A spinodal decomposition, in which a single phase is cooled and separates into two different compositions of that same phase."Wikibearwithme (talk) 21:54, 16 January 2016 (UTC)
thread_title:  spinodal decomposition 

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thread_title:  External links modified 

message: This was removed because it "appeared to be spam".  It is not spam.  The publications have a following of significant physicists and economists, and have been published in reputable physics and economics journals.  Do not confuse the "newness" of the field of econophysics with the posting of spam.  The readers can verify that the main author is being followed by the very notable economist Alan Kirman (formerly of Institute of Advanced Study, Princeton, and also IHES).  The main author was also "facebook friended" by nobel laureate in economics Edmund Phelps, whose work on partial information theory partially inspired the ideas of bounded rationality in the work.
UPSHOT:  please do your homework and read the article on Econophysics before altering this new section.  — Preceding unsigned comment added by 2602:301:772A:E580:E477:F887:DFC2:9504 (talk) 07:56, 15 December 2017 (UTC)
replies: text: The cited reports are (1) primary source and overly technical and (2) recently published and so uncited by anybody. This does not add up to a wp:rs. The IP that added the paragraph seems to be singly focussed on citing the reports. For these reasons, I will remove the material again. Thank you. Attic Salt (talk) 13:39, 15 December 2017 (UTC)

text: Twitter follows and facebook friend connections are not evidence of reliability or notability. This is an academic setting, and citations are the agreed-upon measure of notability. WeakTrain (talk) 18:31, 17 December 2017 (UTC)

text: Google scholar shows zero citations for both recently published articles. But, more generally, the IP editor needs to recognise that Wikipedia is not a farm for citing his/her favorite (or own) papers. Attic Salt (talk) 15:02, 15 December 2017 (UTC)

text: Please read WP:COI. Attic Salt (talk) 18:16, 16 December 2017 (UTC)

text: The purpose of Wikipedia is to serve as an encyclopedia. WP is not a repository for any paper you think is vaguely relevant. 19:06, 17 December 2017 (UTC)

text: As per this edit by user:WeakTrain: , this material appears to be self-promotional. The link the IP editor provides, asserting "issues with an administrator" is not about my behaviour, as can be checked. Attic Salt (talk) 15:05, 17 December 2017 (UTC)
thread_title:  section added : Phase transition in economics 

message: Type 1 has always first order phase transition, whereas type 2 has a second order phase transition only at zero magnetic field.  — Preceding unsigned comment added by 2607:EA00:107:3407:58D0:E9F4:D3AF:3F18 (talk) 06:10, 23 June 2019 (UTC)
thread_title:  Mistake with Type 1/Type 2 superconductors? 

message: The current version of this article defines a first order phase transition by the presence of latent heat according to the Landau classification (this has been included for a long time, since the 2003 version, see diff). I don't believe that this is universally accepted, as the Bose-Einstein Condensation of an ideal Bose gas has a latent heat given by 
:<math>L = \frac{5}{2} k_BT \frac{g_{5/2}(1)}{g_{3/2}(1)}<\math>,
where all symbols have their usual meanings. Huang uses this to justify calling BEC a first order phase transition in the old Ehrenfest classification. However, BEC is considered a second order phase transition (Pitaevski and Stringari) via the spontaneous breaking of gauge symmetry in the Ginzburg-landau sense (this works for both free fields and phi-4 theory).
Therefore, perhaps it would be prudent to remove any mention of latent heat from the Landau Classification, and move it to the Enrenfest classification. If this issue has already been raised and resolved, then can somebody please point me to the relevant discussion, as I cannot find it. 43.252.249.11 (talk) 15:29, 1 June 2020 (UTC)
thread_title:  Latent Heat