Question about a barrier potential E<V

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SUMMARY

The discussion focuses on calculating the transmitted coefficient (T) and reflected coefficient (R) for a quantum mechanical barrier potential where the energy (E) is less than the potential (V). The user presents wave functions for three regions: incident (Ψ_I), potential barrier (Ψ_II), and transmitted (Ψ_III). The key equations used are R = |J_ref/J_inc| and T = |J_tran/J_inc|, where J represents the probability current. The user encounters an indeterminate form (0/0) for both R and T when analyzing the wave functions in the potential barrier region, indicating a need for further clarification on the interpretation of these coefficients.

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Homework Statement


Question_________________________________________________________________________________
Find transmitted coefficient and reflected coefficient in case barrier potential E<V ?
determine.
##Ψ_{I} = Ae^{ikx}+Be^{-ikx}##
##Ψ_{II} = De^{βx}+Ee^{-βx}##
##Ψ_{III} = Ce^{ikx}##

Homework Equations


___________________________________________________________________________________________
##R = |\frac{J_{ref}}{J_{inc}}|##
##T = |\frac{J_{tran}}{J_{inc}}|##
and J is Probability current (https://en.wikipedia.org/wiki/Probability_current)
__________________________________________________________________
For transmitted coefficient and reflected coefficient between ##Ψ_{I}## and ##Ψ_{III}##
where
incident wave = ## Ae^{ikx} ##
reflect wave = ## Be^{-ikx} ##
transmit wave = ## Ce^{ikx} ##
I can find a solution for this case.
https://en.wikipedia.org/wiki/Rectangular_potential_barrier#E_<_V0 << Here is the answer.
___________________________________________________________________________________________

The Attempt at a Solution


But my question is asked in the case transmitted coefficient and reflected coefficient between ##Ψ_{II}## and ##Ψ_{III}##.
I know
incident wave = ## De^{βx} ##
reflect wave = ## Ee^{-βx} ##
transmit wave = ## Ce^{ikx} ##

I checked it
##J = \frac{ħ}{2mi}(Ψ^* \frac{dΨ}{dx}-Ψ\frac{dΨ^*}{dx})##
I seen that incident wave and reflect wave are real function.
So ##J_{inc}=0## and ##J_{ref}=0##
Because ##Ψ^* \frac{dΨ}{dx}-Ψ\frac{dΨ^*}{dx}=Ψ\frac{dΨ}{dx}-Ψ\frac{dΨ}{dx}=0##
But transmit wave is complex function.
So ##J_{tran}=\frac{ħk}{m}|C|^2##
From Eq.
##R = |\frac{J_{ref}}{J_{inc}}|##
##T = |\frac{J_{tran}}{J_{inc}}|##
in this case ##R = \frac{0}{0}## and ##T = \frac{ \frac{ħk}{m}|C|^2}{0}##
what does mean?
##R = \frac{0}{0}## and ##T = \frac{ \frac{ħk}{m}|C|^2}{0}##
Or i miss something ? please re check my solution
 

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Check out the wavefunctions for the step function potential
(you can always add solutions to the homogeneous equation - as long as they sum up to zero)
 
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