Help: Planck Scale and Fine Structure Constant

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SUMMARY

The discussion centers on the relationship between the Fine Structure Constant (FSC) and the Planck Constant, specifically the reduced Planck constant (h-bar). The FSC is a unitless constant defined as α = e²/(ħc4πε₀), illustrating its independence from any scale or system of units. The reduced Planck constant is inversely proportional to the FSC and is influenced by several factors, including the electron mass and the Rydberg constant, as shown in the equation h-bar = mec²α²/(2cR). Both constants are integral to fundamental physics equations, highlighting their universal significance.

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1Truthseeker
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Could someone explain the relationship between the FSC and the Planck Scale? What are they in relation to each other. I know what the Planck Scale is, and I even have a loose understanding of the FSC, but what of them in contrast and comparison? And how does the FSC affect QM, if at all?

Thanks!

-Truth

PS - my apologies, it should read "Planck Constant"!
 
Last edited:
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I am not sure I understand your question. One of the beauties of the fine structure constant is that it is unitless, i.e., independent of any scale or system of units.
Bob S
 
Both describe the very very tiny. I would like to know the difference between them. And how they are related, if at all?
 
\alpha = \frac{e^2}{\hbar c\,4\pi\epsilon_0}
That's the relationship... both of them are numbers that keep popping up in important physics formulas. They're universal constants. I'm not really sure what else you're after.
 
diazona said:
\alpha = \frac{e^2}{\hbar c\,4\pi\epsilon_0}
That's the relationship... both of them are numbers that keep popping up in important physics formulas. They're universal constants. I'm not really sure what else you're after.

Why is the reduced Planck constant inversely proportional to the fine structure constant?
 
Last edited:
1Truthseeker said:
Why is the reduced Planck constant inversely proportional to the fine structure constant?
The reduced Planck constant is given by

h-bar = e2/(4πε0cα).

So the reduced Planck constant is scale dependent on a lot of factors, excluding only 4, π, and α, which are scale independent (unitless).

A better question is why does the reduced Planck constant depend quadratically on the fine strucure constant in

h-bar = mec2α2/(2cR)

where mec2 is the electron mass and R is the Rydberg constant.

Most fundamental is the ratio of the Rydberg energy RE = 13.606 eV to the electron mass:

RE//mec2 = α2/2 which is unitless and therefore scale independent.

Bob S
 

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