Time Dependent Schrodinger Equation

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SUMMARY

The discussion centers on demonstrating that the wave function ##\Psi(x,t)=Asin(kx-ωt)## does not satisfy the Time-Dependent Schrödinger Equation (TDSE). Participants analyze the equation ##-\frac{\hbar}{2m}\frac{\partial^2\psi(x,t)}{{\partial}x^2}+V(x,t)\psi(x,t)=i\hbar\frac{\partial\psi(x,t)}{{\partial}t## by substituting the wave function and simplifying the resulting differential equation. Key insights include the necessity of performing second derivatives with respect to x and first derivatives with respect to t, and the assumption of a potential V=0 for simplification. Ultimately, the discussion concludes that for a wave function to satisfy the TDSE, it must reduce to the form ##\hbar\omega=\frac{\hbar^2k^2}{2m}+V_o##.

PREREQUISITES
  • Understanding of the Time-Dependent Schrödinger Equation (TDSE)
  • Knowledge of differential equations, specifically second-order partial derivatives
  • Familiarity with wave functions in quantum mechanics
  • Basic concepts of quantum potential energy (V) in the context of wave functions
NEXT STEPS
  • Review the derivation of the Time-Dependent Schrödinger Equation
  • Study the implications of potential energy in quantum mechanics
  • Learn about wave function normalization and its significance
  • Explore the relationship between wave functions and energy eigenvalues in quantum systems
USEFUL FOR

Students of quantum mechanics, physicists, and educators looking to deepen their understanding of the Time-Dependent Schrödinger Equation and wave function analysis.

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Homework Statement


Show that the wave function ##\Psi(x,t)=Asin(kx-ωt)## does not satisfy the time dependent Schrödinger Equation.


Homework Equations



##-\frac{\hbar}{2m}\frac{\partial^2\psi(x,t)}{{\partial}x^2}+V(x,t)\psi(x,t)=i\hbar\frac{\partial\psi(x,t)}{{\partial}t}##

The Attempt at a Solution


So first step is I plug in the wave function:

##-\frac{\hbar}{2m}\frac{\partial^2Asin(kx-ωt)}{{\partial}x^2}+V(x,t)Asin(kx-ωt)=i\hbar\frac{{\partial}Asin(kx-ωt)}{{\partial}t}##

From here, I have a differential equation, which, I'm pretty sure I can't solve, but I'm mostly going off the fact that the question says to show that this wave function "does not satisfy.."

But I'm really unsure on how to show this..I don't remember a lot from DiffEq, but I can see that I can't do separation of variables here.
 
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Quote "I don't remember a lot from DiffEq". Time to do a good review, isn't it? To keep it simple assume V = 0 and do the partial derivatives. What do you get?
 
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I couldn't agree more.

##\frac{\hbar^2}{2m}Ak^2sin(kx-{\omega}t){\partial}x+0=-i{\hbar}A{\omega}cos(kx-{\omega}t){\partial}t##
 
Why have you written \partial x and \partial t at the end of the partial derivatives? That doesn't make sense. Just derive two times wrt. to x on the one side and once by t on the other and check that the given function doesn't fulfill the equation after you've sorted out all the constants.
 
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Got it, I've forgotten a lot. It's been over year since DiffEq, and a year before that since Cal 3. Thank you.

EDIT:

Actually, one last thing. Why can I let V=0?

EDIT: Nevermind, I think I see what is going on.

This may be overly simplistic, but basically in order for a wave function to satisfy the Time-Dependent Schrödinger equation, do we have to be able to reduce the equation down to:

##\hbar\omega=\frac{\hbar^2k^2}{2m}+V_o##
 
Last edited:

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