Variational method in a finite square well

Click For Summary
SUMMARY

The discussion centers on proving the existence of one bound state for a finite square well using the variational method. Jacob initially used the trial wave function e^(-bx^2) and derived the energy equation E(b)=(hbar^2)b/2m - V, where V represents the well's depth. However, he encountered difficulties in finding a critical value for b by taking the derivative. Another participant suggested that Jacob may have miscalculated the potential, emphasizing the need to evaluate the integral -V ∫_0^a ψ*(x) ψ(x) dx, which involves error functions.

PREREQUISITES
  • Understanding of the variational method in quantum mechanics
  • Familiarity with finite square well potentials
  • Knowledge of wave functions and their properties
  • Basic calculus, particularly differentiation and integration
NEXT STEPS
  • Study the variational principle in quantum mechanics
  • Learn how to evaluate integrals involving wave functions
  • Research error functions and their applications in quantum mechanics
  • Explore different trial wave functions for bound state problems
USEFUL FOR

Quantum mechanics students, physicists working on potential wells, and researchers interested in variational methods for bound state analysis.

jcsimon89
Messages
1
Reaction score
0
I am trying to prove that there is always one bound state for a finite square well using variational method, and I am stuck. I've tried using e^(-bx^2) as my trial wave function, but I am left with E(b)=(hbar^2)b/2m - V, where V is the depth of the well. In this equation, taking the derivative in terms of b and setting it to zero doesn't lead to a critical value of b, am I doing something wrong?

Thanks,
Jacob
 
Physics news on Phys.org
I think you evaluated your potential wrong. If your well goes from 0 to a, then you need to evaluate
<br /> -V \int_0^a \psi^*(x) \psi(x) dx<br />
which should give you error functions.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 0 ·
Replies
0
Views
2K
  • · Replies 28 ·
Replies
28
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K