A practice problem with Schrodinger equation

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SUMMARY

The discussion centers on the application of the time-independent Schrödinger equation, specifically when the energy E is set to 0. Participants confirm that the equation simplifies to $$-\frac{\hbar^2}{2m}\psi''(x) + V(x)\psi(x) = 0$$, indicating that the right-hand side becomes zero. The conversation highlights the importance of recognizing that the wave function, $$\psi(x)$$, must include a constant term, particularly in the context of the simple harmonic oscillator potential, $$V(x) = -\frac{1}{2}kx^2$$. Additionally, the concept of separating variables into spatial and temporal components, specifically $$\phi(x)$$ and $$\psi(t)$$, is discussed, emphasizing that time dependence is not a concern when solving the non-time-dependent equation.

PREREQUISITES
  • Understanding of the time-independent Schrödinger equation
  • Familiarity with wave functions and energy eigenstates
  • Knowledge of potential energy functions in quantum mechanics, particularly for harmonic oscillators
  • Basic concepts of quantum mechanics, including separation of variables
NEXT STEPS
  • Study the derivation and implications of the time-independent Schrödinger equation
  • Explore the potential energy function for the simple harmonic oscillator in detail
  • Learn about the separation of variables technique in quantum mechanics
  • Investigate the role of constants in wave functions and their physical significance
USEFUL FOR

Students and professionals in quantum mechanics, particularly those studying wave functions and the Schrödinger equation, as well as educators looking for practical examples in teaching quantum concepts.

drop_out_kid
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Homework Statement
In the comment section
Relevant Equations
Schrodinger equation
1649895929014.png


So my question is.. Is Schrödinger equation for this problem like this?:
1649896912516.png


How to use the condition that E=0?

Thank you
 
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The time-independent Schrödinger equation is
$$-\frac{\hbar^2}{2m}\psi''(x) + V(x)\psi(x) = E\psi(x).$$ When you set ##E=0##, the righthand side becomes 0.
 
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vela said:
The time-independent Schrödinger equation is
$$-\frac{\hbar^2}{2m}\psi''(x) + V(x)\psi(x) = E\psi(x).$$ When you set ##E=0##, the righthand side becomes 0.
Exactly. And I solve it as this:
1649897690574.png


Could you take a look if it's right? I thought this is probably too trivial that xmin is just 0?
 
I'd expect there should be a constant term as well.

The given wave function is one of the energy eigenstates for the simple harmonic oscillator. What's the potential energy function for the simple harmonic oscillator?
 
vela said:
I'd expect there should be a constant term as well.

The given wave function is one of the energy eigenstates for the simple harmonic oscillator. What's the potential energy function for the simple harmonic oscillator?
-1/2kx^2?

So where is the constant come from ?? the phi(x) got cancelled..

Thank you so much for answering my question!
 
##\psi''## should have two terms. Neither term disappears when you divide by ##\psi##.
 
vela said:
##\psi''## should have two terms. Neither term disappears when you divide by ##\psi##.
Thank you so much... I am doing it again
 
vela said:
##\psi''## should have two terms. Neither term disappears when you divide by ##\psi##.
So yes there's a constant! And I got another question: should I time a sai(t)? I am not familiar with it but I saw that phi(x,t) usually written to phi(x)*sai(t) and sai(t) is usually an exponential
 
drop_out_kid said:
So yes there's a constant! And I got another question: should I time a sai(t)? I am not familiar with it but I saw that phi(x,t) usually written to phi(x)*sai(t) and sai(t) is usually an exponential
I have no idea of what is a sai(t). But if you are solving the Schrödinger ///non-time-dependent/// equation (the one you posted (missing an E of energy) at the first post) you should not worry with time.
 
  • #10
LCSphysicist said:
I have no idea of what is a sai(t). But if you are solving the Schrödinger ///non-time-dependent/// equation (the one you posted (missing an E of energy) at the first post) you should not worry with time.
Yes I think so. Now I got last problem of my assignment and last hour of due, thank you !
 

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