Finite Square Well Analysis: Odd Bound States & Scattering States

In summary, the conversation discusses a problem with the finite square well and the analysis of odd bound states. The speaker must examine the limiting cases and determine if there is always at least one odd bound state. The question arises about the nature of E=0 as a solution and whether it corresponds to a bound state or a scattering state. The conversation also briefly touches on the definitions of bound and scattering states. The conclusion is that E=0 does not correspond to a bound state and the wave function is not normalizable.
  • #1
broegger
257
0
Hi,

I have a problem with the finite square well. I have to analyze the odd bound states of the finite square well,

[tex] V(x)=
\begin{cases}
-V_0 & \text{for } -a<x<a\\
0 & \text{otherwise}
\end{cases}.
[/tex]​

Specifically, I have to examine the limiting cases (wide, deep well and narrow, shallow well) and find out, if there is always at least one odd bound state.

When I try to determine the energies of these odd states, I find that E=0 is always a solution. Is E=0 a bound state, a scattering state or what?

Also, what exactly are scattering states?
 
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  • #2
broegger said:
Hi,

I have a problem with the finite square well. I have to analyze the odd bound states of the finite square well,

[tex] V(x)=
\begin{cases}
-V_0 & \text{for } -a<x<a\\
0 & \text{otherwise}
\end{cases}.
[/tex]​

Specifically, I have to examine the limiting cases (wide, deep well and narrow, shallow well) and find out, if there is always at least one odd bound state.

Okay,did you find the "normal" /general sollution...?Odd states refer to the behavior of wavefunctions under parity...In your case,depending on the E:V,it could be only [itex] \sin [/itex] or [itex] \sinh [/tex].

Bound states are normalizable states,physical states according to I-st postulate...In your case,which would be those...??
Scattering states would correspond to nonnormalizable states...

Daniel.
 
  • #3
Scattering states are those that satisfy the Somerfeld Radiation Condition, which is obeyed if a state behaves like a plane wave at infinity. Drop a rock in a water wave, say from a speed boat. The wave pattern will settle down and stabilize-- the original wave will still be going, as will "scattered waves" generated by the rock -- and these waves will behave like free waves, once they've gone out a bit from the rock's splash.
Regards,
Reilly Atkinson
 
  • #4
dextercioby said:
Okay,did you find the "normal" /general sollution...?Odd states refer to the behavior of wavefunctions under parity...In your case,depending on the E:V,it could be only [itex] \sin [/itex] or [itex] \sinh [/tex].

Bound states are normalizable states,physical states according to I-st postulate...In your case,which would be those...??
Scattering states would correspond to nonnormalizable states...

Daniel.

My question is really, does E=0 correspond to a bound state? I hope not, because this implies that there is always one odd, bound state (and there isn't according to the book).
 
  • #5
No,the wave function is a "sine",which is not a bound state...It's not normalizable...

Daniel.
 
  • #6
Ok, thanks!
 

1. What is a finite square well?

A finite square well is a model used in quantum mechanics to describe a potential energy barrier with a finite range. It is a simple yet useful system for studying the behavior of particles in confined spaces.

2. What are bound states and scattering states in a finite square well?

Bound states are energy states that are allowed within the finite square well potential. These states have discrete energies and are confined within the well. Scattering states, on the other hand, are energy states that are not allowed within the well, but have the potential to escape or tunnel through the well. They have continuous energies and represent particles that are scattered by the well.

3. How are odd bound states and scattering states different from even bound states and scattering states?

Odd bound states and scattering states have wavefunctions that are antisymmetric, meaning they change sign under spatial inversion. This results in a node, or point of zero amplitude, at the center of the well. Even bound states and scattering states have wavefunctions that are symmetric and have no nodes at the center.

4. How are odd bound states and scattering states affected by the depth and width of the finite square well?

The depth and width of the finite square well affect the energies of the odd bound states and scattering states. As the well becomes deeper, the energies of the odd states decrease and the energies of the even states increase. As the width of the well increases, the energies of both the odd and even states decrease.

5. What are some applications of finite square well analysis?

Finite square well analysis has applications in various fields such as solid-state physics, nuclear physics, and quantum computing. It is used to study the behavior of electrons in semiconductor devices, the properties of atomic nuclei, and the design of quantum computing algorithms. It can also be applied to other quantum systems with similar potential energy barriers.

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