Simple time-independent perturbation problem. QM

In summary, the conversation discusses the implementation of a delta-function potential in the center of an infinite square well and finding the first order correction to the allowed energies. It is explained that the energies are not perturbed for even n due to the wave functions being odd with respect to the center of the well.
  • #1
armis
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Homework Statement


"Suppose we put a delta-function in the center of the infinite square well:
[tex] {H^{'}} = \alpha\delta(x-a/2) [/tex] where a is a constant. Find the first order correction to the allowed energies. Explain why the energies are not peturbed for even n"

Homework Equations



The Attempt at a Solution



Just to make sure. The energies for even n are not peturbed because the wave functions are odd with respect to the center of the well, thus equal to zero at those points where the delta-function potential is (if our square well is from 0 to a). Is that correct?
 
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  • #2
Yes, that's correct!
 
  • #3
thanks
 

FAQ: Simple time-independent perturbation problem. QM

What is a time-independent perturbation problem in quantum mechanics?

A time-independent perturbation problem in quantum mechanics involves studying the behavior of a quantum system when an external influence is applied to it, without taking into account the effects of time. This allows for the calculation of the system's energy levels and wavefunctions.

How is the perturbation theory used to solve these problems?

The perturbation theory is a mathematical method used to approximate the behavior of a system when a small perturbation is applied. In the case of time-independent perturbation problems, this involves adding a perturbation term to the original Hamiltonian operator and solving for the new energy levels and wavefunctions.

What are some common examples of time-independent perturbation problems?

Some common examples of time-independent perturbation problems in quantum mechanics include the Stark effect, where an external electric field perturbs the energy levels of an atom, and the Zeeman effect, where an external magnetic field perturbs the energy levels of an atom or molecule.

How does the strength of the perturbation affect the system?

The strength of the perturbation is directly related to the size of the energy shift in the system. A stronger perturbation will result in a larger energy shift and potentially more significant changes in the system's behavior.

What are the limitations of the perturbation theory in solving time-independent problems?

The perturbation theory is based on making small approximations and is therefore not applicable to systems with large perturbations. It also assumes that the perturbation is time-independent and can only be used to approximate the behavior of a system up to a certain level of accuracy.

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