I was wondering if the electron compton wavelength divided by 2pi is an
invariant quantity? A main result from compton scattering is,

lambda_C/2pi = hbar/m_e*c

Everything on the right hand side of the equation is invariant, so why
wouldn't this length be invariant?

FrediFizzx

FrediFizzx wrote in message
...
I was wondering if the electron compton wavelength divided by 2pi is an
invariant quantity? A main result from compton scattering is,

lambda_C/2pi = hbar/m_e*c

Everything on the right hand side of the equation is invariant, so why
wouldn't this length be invariant?

FrediFizzx

Old Man Thinks that freddi is correct. In anology to

(mc^2)^2 = E^2 - (pc)^2

or (mc)^2 = (E / c)^2 - p^2

wherein mc^2 is Lorentz invariant, we can write

(hbar / L_compton)^2 = (hbar / L_einstein)^2 - (hbar / L_debroglie)^2

[Old Man]

FrediFizzx wrote:
I was wondering if the electron compton wavelength divided by 2pi is an
invariant quantity? A main result from compton scattering is,

lambda_C/2pi = hbar/m_e*c

Everything on the right hand side of the equation is invariant, so why
wouldn't this length be invariant?

Are you sure the m is the rest mass?

Thanks
Bill

"Bill Hobba" wrote in message
...
| FrediFizzx wrote:
| I was wondering if the electron compton wavelength divided by 2pi is
an
| invariant quantity? A main result from compton scattering is,
|
| lambda_C/2pi = hbar/m_e*c
|
| Everything on the right hand side of the equation is invariant, so why
| wouldn't this length be invariant?
|
| Are you sure the m is the rest mass?

Why wouldn't it be?

FrediFizzx

"Old Man" wrote in message
...
|
| FrediFizzx wrote in message
| ...
| I was wondering if the electron compton wavelength divided by 2pi is
an
| invariant quantity? A main result from compton scattering is,
|
| lambda_C/2pi = hbar/m_e*c
|
| Everything on the right hand side of the equation is invariant, so why
| wouldn't this length be invariant?
|
| FrediFizzx
|
| Old Man Thinks that freddi is correct. In anology to
|
| (mc^2)^2 = E^2 - (pc)^2
|
| or (mc)^2 = (E / c)^2 - p^2
|
| wherein mc^2 is Lorentz invariant, we can write
|
| (hbar / L_compton)^2 = (hbar / L_einstein)^2 - (hbar / L_debroglie)^2
|
| [Old Man]

Thanks Old Man. Then wouldn't photon energy at the electron compton
frequency be invariant? This seems strange. From the looks of your
equation above, it isn't. We lose the rest mass energy of the electron.

FrediFizzx

FrediFizzx wrote:
I was wondering if the electron compton wavelength divided by 2pi is an
invariant quantity? A main result from compton scattering is,

lambda_C/2pi = hbar/m_e*c


That's not a "result", it's a "definition" - so in a trivial sense
it is "invariant", although not in the way we usually apply the
term. The Compton Wavelenth is not a fundamental
property, but rather a dimensional shorthand to tidy up the
expression for the wavelenth shift resulting from scattering
gamma rays off of effectively stationary electrons. The
equation can be written down just fine without it. For
dimensional reasons, you'll also see the Compton wavelenth
popping up in other contexts as well; however, if you examine
Compton Scattring in a different frame (i.e. one in which
the electrons are moving), you get a different scattering
relationship.


-Eric

Everything on the right hand side of the equation is invariant, so why
wouldn't this length be invariant?

FrediFizzx




--
-------------------------------------------------------------------
Eric Prebys, Fermi National Accelerator Laboratory
Office: 630-840-8369, Email:
WWW: http://home.fnal.gov/~prebys
-------------------------------------------------------------------

| FrediFizzx wrote:
| I was wondering if the electron compton wavelength divided by 2pi is
an
| invariant quantity? A main result from compton scattering is,
|
| lambda_C/2pi = hbar/m_e*c
|
| Everything on the right hand side of the equation is invariant, so why
| wouldn't this length be invariant?
|

Bill Hobba wrote:
| Are you sure the m is the rest mass?


FrediFizzx wrote;
Why wouldn't it be?

No particular reason except it has been a while since I looked at compton
wavelength and thought it may have been an out for the invariance. I cant
recall if it is invariant or not. A quick look at the textbooks I had left
me none the wiser.

Thanks
Bill

"Bill Hobba" wrote in message
...
|
| | FrediFizzx wrote:
| | I was wondering if the electron compton wavelength divided by 2pi is
| an
| | invariant quantity? A main result from compton scattering is,
| |
| | lambda_C/2pi = hbar/m_e*c
| |
| | Everything on the right hand side of the equation is invariant, so
why
| | wouldn't this length be invariant?
| |
|
| Bill Hobba wrote:
| | Are you sure the m is the rest mass?
|
|
| FrediFizzx wrote;
| Why wouldn't it be?
|
| No particular reason except it has been a while since I looked at compton
| wavelength and thought it may have been an out for the invariance. I cant
| recall if it is invariant or not. A quick look at the textbooks I had
left
| me none the wiser.

Eric says it is a definition, which seems to be right. We just take three
invariant constants and produce an invariant length. However, now that we
have this invariant length, what is its significance? This seems to be
somewhat mind boggling. Does this mean this length will always be the same
no matter what frame you are looking from? Seems like it would mean that.

FrediFizzx

Regarding the Compton wavelength Bill Hobba wrote:|
| No particular reason except it has been a while since I looked at
compton
| wavelength and thought it may have been an out for the invariance. I
cant
| recall if it is invariant or not. A quick look at the textbooks I had
left
| me none the wiser.


FrediFizzx replied:
Eric says it is a definition, which seems to be right. We just take three
invariant constants and produce an invariant length. However, now that we
have this invariant length, what is its significance? This seems to be
somewhat mind boggling. Does this mean this length will always be the
same
no matter what frame you are looking from? Seems like it would mean that.

Not really because one would need to know the physical meaning in other
reference frames. My recollection of the Compton wavelength is such that I
have no idea what that. Suppose you need to have a read in a textbook.

Thanks
Bill

"Bill Hobba" wrote in message
...
|
| Regarding the Compton wavelength Bill Hobba wrote:|
| | No particular reason except it has been a while since I looked at
| compton
| | wavelength and thought it may have been an out for the invariance. I
| cant
| | recall if it is invariant or not. A quick look at the textbooks I had
| left
| | me none the wiser.
|
|
| FrediFizzx replied:
| Eric says it is a definition, which seems to be right. We just take
three
| invariant constants and produce an invariant length. However, now that
we
| have this invariant length, what is its significance? This seems to be
| somewhat mind boggling. Does this mean this length will always be the
| same
| no matter what frame you are looking from? Seems like it would mean
that.
|
| Not really because one would need to know the physical meaning in other
| reference frames. My recollection of the Compton wavelength is such that
I
| have no idea what that. Suppose you need to have a read in a textbook.
|
| Thanks
| Bill

If it is just a definition, which I am sure that it is, then maybe mass is
our way out of this as you originally proposed. We know that mass can be
converted completely to energy so to me that would mean that it can't be 100
percent invariant. It is maybe only "partially" invariant. Yeah, must hit
the books for this one. But maybe it is just due to the compton wavelength
applying to a photon and the mass is applying to an electron.

FrediFizzx