Talk:Metastability

From Wikipedia, the free encyclopedia
Jump to: navigation, search
WikiProject Physics (Rated Start-class, High-importance)
WikiProject icon This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Start-Class article Start  This article has been rated as Start-Class on the project's quality scale.
 High  This article has been rated as High-importance on the project's importance scale.
 
WikiProject Systems (Rated Disambig-class, Mid-importance)
WikiProject icon This page is within the scope of WikiProject Systems, which collaborates on articles related to systems and systems science.
Disambiguation page Disambig  This page does not require a rating on the project's quality scale.
 Mid  This page has been rated as Mid-importance on the project's importance scale.
Taskforce icon
This page is within the field of Dynamical systems.
 

Ferromagnetic materials[edit]

-Ferromagnetic materials also present a metastable behavior. If one considers the presence of an external magnetic field, the equilibrium state is obtained when the material aligns its magnetization with the exterior field. But if the sample already presents a residual magnetization, which is in the opposite direction of a small exterior field, then the system becomes metastable. This situation has a very good description, what makes it even more interesting. —Preceding unsigned comment added by 129.132.146.33 (talk) 11:05, 17 July 2008 (UTC)

Is this wrong?[edit]

"It is analogous to being balanced precisely at the top of a round hill, rather than safely at the bottom of a valley" - -Wouldn't that be a definition of unstable (i.e. a small disturbance moves the system further and further away from the initial point) rather than metastable? Commutator (talk) 07:45, 13 June 2008 (UTC)

Metastability vs hysteresis[edit]

I think that the article would gain from distinguishing between the words metastable equilibrium and hysteresis. A system at metastable equilibrium is well described by Statistical mechanics and the fluctuations obey the fluctuation dissipation theorem. On the other hand hysteresis refers to the fact that most physical systems do not reach equilibrium instantaneously.

EDIT: Perhaps it is better to write it the following way:

A metastable system can equilibrium system for all purposes. As an example the state of a metastable system is fully described by the value of temperature and pressure. (unsigned comment)

I added a "see also" link, but not an explanation of the difference between the two concepts. They both seem to have pretty clear definitions. If anyone feels the need to add this contrast, I would say it this way: hysteresis is the dependence of state on the history of the environment, not just the current environment (which may or may not imply equilibrium) and metastability is equilibrium (a stable state) outside the ground state. -- Beland (talk) 12:51, 6 June 2008 (UTC)

Explaining metastability[edit]

When I have to explain metastability, I always use the example of atomic nuclei. Iron is the only stable atomic nucleus. The rest of the atomic nuclei are only metastable. Nevertheless we can use statistical mechanics to describe chemical systems. The key feature here is separation of time scales. The timescale for atomic processes is much longer than the time scale of chemical reactions.

Actually chemical substances are another example of metastability. In quantum chemistry they have several methods for calculating the speed of a chemical reaction. All these methods rely on a crucial assumption that the vibration of the molecule is well described by a thermal equilibrium distribution. In other words they rely on an assumption of metastability. Once again the key assumption is separating time scales. The time needed to attain vibrational equilibrium is shorter than the inverse reaction rate.

Created two subarticles[edit]

I created two subarticles in order to be able to distinguish and specialize them.--Carl Hewitt 04:43, 21 July 2005 (UTC)

Additional note: Physics page no longer explains metastable. (unsigned comment)

I've merged several articles back into this one, so that the general scientific concept could be explained, and then applied to the various fields. Some subarticles remain. -- Beland (talk) 12:52, 6 June 2008 (UTC)

Dropped text[edit]

I dropped the following text during a merge:

Systems prone to metastable states tend to exhibit power law behavior when measured over time. This is because the interactions are scale invariant. For instance, adding a single grain to a sandpile can result in anything from a small local disturbance (common) to the collapse of almost the entire pile (rare).

I'm not sure this is correct, and it's unreferenced and rather sweeping in scope. References would be appreciated if this claim is defensible. -- Beland (talk) 01:40, 6 June 2008 (UTC)


Hello! I (wavepacket) added that text. I agree it is rather sweeping, but of course there is the usual author's tension between readable prose and mathematically precise terminology. I am not yet good at both at the same time. One reference might be Manfred Schroeder's "Fractals, Chaos, Power Laws" (1991, WH Freeman and Company). Chapter 4 (Power Laws: Endless Sources of Self-Similarity) notes that "scaling invariance results from the fact that homogeneous power laws lack natural scales...". In his references, Schroeder points to examples from RM May (Science 214 pg 1441), and a very cool power-law distribution of impact rates vs. particle size graph from Schoemaker, US Geological Survey.

Expert attention needed?[edit]

There's an expert attention needed tag in the article, but it's not particularly obvious why. (Obviously any Wikipedia article would be benefitted by having an expert view...) Unless someone suggests what specific issue should be looked at, I'll clear the tag. Djr32 (talk) 18:01, 1 August 2009 (UTC)

Done. Djr32 (talk) 20:54, 2 October 2009 (UTC)

Metastability in electronics[edit]

There's a separate article about metastability in electronics - should add a link from this section to the article —Preceding unsigned comment added by 132.68.244.59 (talk) 20:44, 15 February 2010 (UTC)

Basic attention needed[edit]

You better believe this article is "start class". It is a simple concept at its heart that is impossible to understand based on this article unless, perhaps, you already know what it is. When dictionary.com is more informative, one has to wonder what planet you guys are on. I have entered a new article on metastability on simple.wikipedia.org which actually says what metastability is, a goal that apparently is out of reach on en.wikipedia.org. —Preceding unsigned comment added by 70.232.68.182 (talk), 24 May 2010 (UTC)

Lead section inadequate[edit]

I find that the lead section is absolutely unintelligible, with too many lucubrations and too few sound concepts. By reading it, I can understand metastability only because I already know what is metastability. So, I think it is to be completely rewritten. --GianniG46 (talk) 19:11, 17 October 2010 (UTC)

Mechanics[edit]

perhaps can add a reference to the mechanical "over center" lock or latch. — Preceding unsigned comment added by Charlieb000 (talkcontribs) 00:45, 10 January 2014 (UTC)