Finite square well potential numerical solution

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SUMMARY

The discussion focuses on the numerical solution for eigenstates in a finite square well potential using the effective length approximation. The user begins by calculating eigenstates for an infinite square well and defines an effective length as the nominal length plus 2/alpha, where alpha is related to energy (E). The iterative process converges when the energy values stabilize (En=En-1), leading to accurate eigenstates. The user questions the effectiveness of using 4/alpha instead of 2/alpha, indicating a need for deeper understanding of the iteration process and its implications on the wave function.

PREREQUISITES
  • Understanding of quantum mechanics, specifically the finite square well potential
  • Familiarity with numerical methods for solving differential equations, such as the Cooley-Numerov method
  • Knowledge of eigenstates and eigenvalues in quantum systems
  • Basic grasp of iterative methods and convergence criteria in numerical analysis
NEXT STEPS
  • Research the Cooley-Numerov method for solving the 1-D Schrödinger equation
  • Explore the concept of effective potential in quantum mechanics
  • Study the implications of different alpha definitions on wave function behavior
  • Investigate convergence criteria in numerical solutions for differential equations
USEFUL FOR

Quantum physicists, computational physicists, and students studying quantum mechanics who are interested in numerical methods for solving potential problems.

Braggplane
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hi guys i need some help with the iteration made in a numerical solution for the eigenstates in a finite square well potential using the effective length approximation

First, i find the eigenstate for a infinite square well, then i define the related alpha and i use it to define an effective length as the nominal one plus 2/alpha, and so on.

the n iteration will use the nominal length plus 2/alpha(n-1) to find the n eigenstate and to define the n alpha (which depends on E)

In this way my equations converge when En=En-1 (and i find the rigth eigenstates).

I have a conceptual doubt: when i define the new length, is the iteration trying to fit the old solution in a new well? (nominal length plus 2/alpha contain almost all the wave function)

but why if i make the same thing with 4/alpha doesn't work?
 
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Braggplane said:
hi guys i need some help with the iteration made in a numerical solution for the eigenstates in a finite square well potential using the effective length approximation

First, i find the eigenstate for a infinite square well, then i define the related alpha and i use it to define an effective length as the nominal one plus 2/alpha, and so on.

the n iteration will use the nominal length plus 2/alpha(n-1) to find the n eigenstate and to define the n alpha (which depends on E)

In this way my equations converge when En=En-1 (and i find the rigth eigenstates).

I have a conceptual doubt: when i define the new length, is the iteration trying to fit the old solution in a new well? (nominal length plus 2/alpha contain almost all the wave function)

but why if i make the same thing with 4/alpha doesn't work?

I think that we need to see a bit more explained. I am familiar with some methods (Cooley-Numerov) of numerically solving the 1-D Schrödinger equation.

What are you calculating as you iterate? What are you converging to?
 

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