Talk:Compton wavelength

message: This page says the Compton wavelength of the electron
is .39 times 10-12 meters.  Everyone else says it's
about 2.42 times 10-13 meters.  So, I'm going to change this, to keep people from getting a wrong figure.
But, as the above comment suggests, more careful thought needs to be put into this page.  John Baez 22:11, 23 December 2005 (UTC)
thread_title: Compton wavelength of the electron

message: "The Compton wavelength can be thought of as a fundamental limitation on measuring the position of a particle, taking quantum mechanics and special relativity into account. This depends on the mass m of the particle."
I disagree. It depends on the rest energy of the particle, not the mass.
:\lambda_C = {h c \over E_{rest}} 
and
:{\lambda_C \over 2 \pi} = {\hbar c \over E_{rest}} 
GoldenBoar 18:27, 4 January 2006 (UTC)
replies: text: You are aware that rest mass and rest energy are equivalent, right? --Christopher Thomas 00:44, 8 January 2006 (UTC)
thread_title: Rest mass vs. rest energy

message: What is the image suppose to add to this article?
It seems like it just explores different relations between the various constants. It tries to assign some meaning to this and there is no reference. Also the image contains 6 different quantities, but the text below mentions only 5. 
If this image should remain there should be at least one reference to confirm its claims.  — Preceding unsigned comment added by 130.79.154.17 (talk) 11:16, 6 March 2013 (UTC)
thread_title:  Hijacked by crackpots? 

message: The article contains an error in Relationship to Other Constants, when it claims the non-reduced Compton wavelength applies in the Thomson scattering cross section.  Actually it is the reduced Compton wavelength, as shown in this article:
http://en.wikipedia.org/wiki/Thomson_scattering
Also, I have a physics textbook source: Nuclear and Particle Physics, Second Edition, B.R. Martin, pg 30.
Fastman99 (talk) 23:15, 7 August 2013 (UTC)
thread_title:  Formula for photon scattering WRONG 

message: I find the following paragraph rather questionable.
:Relationship between the reduced and non-reduced Compton wavelength
:The reduced Compton wavelength is a natural representation for mass on the quantum scale. Equations that pertain to mass in the form of mass, like Klein-Gordon and Schrödinger's, use the reduced Compton wavelength. The non-reduced Compton wavelength is a natural representation for mass that has been converted into energy. Equations that pertain to the conversion of mass into energy, or to the wavelengths of photons interacting with mass, use the non-reduced Compton wavelength.
This appears to be a rule of thumb for handling or remembering formulas, or a remark about conventions that are observed in formulas. As such, it is a student's remark, rather than a fundamental physical interpretation. 
I would prefer to express it this way: the relationship is a factor of 2π.
If there is a more fundamental meaning to the "relationship", it should be noted, otherwise this paragraph should be omitted. 84.226.185.221 (talk) 09:08, 12 October 2015 (UTC)
thread_title:  Reduced versus non-reduced paragraph seems to be rather soft 

message: There's a basic lack of flow, or incoherence, in the section entitled "Limitation on measurement".
The goal is to find a fundamental lower bound for the uncertainty Δx in the position of the particle. There are two slightly disparate explanations given.
In the beginning of the section, the position is measured by hitting the particle with a photon. The photon must have a small wavelength in order to measure the position accurately. But then the photon has a high energy, and risks producing a new particle of the same type, which renders the position measurement meaningless. So this gives a fundamental lower bound on Δx.
In the second half of the second, there is not longer any photon. Instead, we work directly with the Heisenberg uncertainty principle Δp Δx ≥ ħ/2 for the particle is invoked. It is combined with an inequality  Δp ≤  mc, because we don't want so much energy uncertainty ΔE as to risk producing a new particle. So again we get a lower bound on Δx.
I realize that these two ways of discussing position-uncertainty are related (it is a very time-honored relationship). But they are not the same argument.
What is confusing is that the two discussions are not clearly distinguished. They kind of merge into one another, as if the second one were a continuation of the first one. One consequence of this is that the first discussion (with the measuring photon) is not brought to its quantitative conclusion. On the other hand, the second discussion (with Δp Δx) seems to have developed amnesia for the photon in the first discussion.
If I "YouRang" contributed any of this, feel free to delete it; it's mostly wrong-headed in a way that I sometimes do.  — Preceding unsigned comment added by YouRang? (talk • contribs) 20:56, 1 September 2016 (UTC)
thread_title:  Inconsistency in the section "Limitation on measurement" 

message: Substituted at 12:08, 29 April 2016 (UTC)
thread_title: Assessment comment

message: Can we have a list of Compton wavelength for all known particles? Jackzhp (talk) 03:42, 24 November 2020 (UTC)
thread_title: A list of Compton wavelength for all known particles

message: The following statement about the Compton wavelength in the introductory part of the current version bothered me.
"It is equivalent to the de Broglie wavelength with v = c."
The formula for the de Broglie wavelength is h/p. In the non-relativistic case this is h/(mv) and of course v=c can formally be set and the Compton wavelength is obtained. But that doesn't make any sense to me. Since the special theory of relativity applies for v->c, the formula in
https://en.m.wikipedia.org/wiki/Matter_wave#Special_relativity
has to be used. Then, de Broglie wavelength -> 0 for v -> c (and v=c for electrons is not physically possible here).
I'm not really an expert in the field. Could someone check? There is also a reference to de Brogli in the text.
 Lojypeityr (talk) 19:56, 17 July 2022 (UTC)
replies: text: Yes, the real speed at which de Broglie and Compton wavelengths are the same is at  v = \frac{c}{\sqrt{2}} . I also saw the error and fixed it before seeing this, same error was on the page for matter waves. Strange-attractor (talk) 18:25, 14 August 2022 (UTC)
thread_title:  Compton and de Broglie wavelength