Quantum mechanics - finite square well

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The discussion focuses on the relationship between transmission (T), reflection (R), and the parameters of a finite square well in quantum mechanics. It highlights confusion regarding how the width and height of the potential well affect T and R, specifically questioning the role of the wave number (k) in these calculations. The formulas for T and R are reiterated, emphasizing their dependence on k, which is derived from the potential energy and the particle's energy. Clarification is sought on the definitions and applications of k in the context of these formulas. Understanding these relationships is crucial for accurately predicting particle behavior in quantum wells.
Graham87
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Homework Statement
In which case would you expect the reflection coefficient to largest, for a particle with energy E?

For which of the energy levels would you expect that the tansmission coefficient would be largest?
Relevant Equations
##R=\frac{|A|^2}{|B|^2}##

##T=1-R##

##k=\sqrt{\frac{2m(V_0-E)}{h}}##

##\psi(x)=Ae^{kx}+Be^{-kx}##
5B8339D6-25BE-4C8D-8B2F-C3F02DEAF4B3.jpeg

In a) I get that T should be largest where V_0 is least wide, because when V_0 is infinitely wide the particle would be fully reflected.
But I don't get how height in b) and energy levels height in c) correlates to T and R.

Is it because of their k? I get the opposite answer from the correct one when I plug k in the R formula. ##R=\frac{|A|^2}{|B|^2}##

##T=1-R##

##k=\sqrt{\frac{2m(V_0-E)}{h}}##

##\psi(x)=Ae^{kx}+Be^{-kx}##Thanks!
 
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Graham87 said:
But I don't get how height in b) and energy levels height in c) correlates to T and R.

Is it because of their k? I get the opposite answer from the correct one when I plug k in the R formula.
You need to define what you mean by ##k##. And what formulas are you using for ##T## and ##R##?
 
vela said:
You need to define what you mean by ##k##. And what formulas are you using for ##T## and ##R##?
Done!
 
I want to find the solution to the integral ##\theta = \int_0^{\theta}\frac{du}{\sqrt{(c-u^2 +2u^3)}}## I can see that ##\frac{d^2u}{d\theta^2} = A +Bu+Cu^2## is a Weierstrass elliptic function, which can be generated from ##\Large(\normalsize\frac{du}{d\theta}\Large)\normalsize^2 = c-u^2 +2u^3## (A = 0, B=-1, C=3) So does this make my integral an elliptic integral? I haven't been able to find a table of integrals anywhere which contains an integral of this form so I'm a bit stuck. TerryW

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