TISE solutions should be combinations-of-eigenstates, why this is not?

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Discussion Overview

The discussion centers around the Time-Independent Schrödinger Equation (TISE) and the nature of its solutions, particularly regarding the linear combinations of eigenstates. Participants explore the implications of linear combinations in the context of free particles and the differences when compared to the Time-Dependent Schrödinger Equation (TDSE).

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that the TISE is a linear equation and suggests that linear combinations of solutions should also be solutions.
  • Another participant questions the formulation of the original question and suggests that modeling a traveling wave with a time-independent model is not feasible.
  • A different participant emphasizes that the TISE encompasses multiple equations, each corresponding to different eigenvalues, and that linear combinations yielding new solutions only occur in cases of degeneracy.

Areas of Agreement / Disagreement

Participants express differing views on the nature of solutions to the TISE, with some agreeing on the linearity of the equation while others challenge the applicability of linear combinations in certain contexts. The discussion remains unresolved regarding the implications of these points.

Contextual Notes

There is a lack of clarity regarding the mathematical formulation of the original question, and assumptions about the nature of eigenstates and degeneracy are not fully explored.

JackeTheDog132
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TL;DR
Why a wave pocket is not a solution of the TISE?
I would really appreciate some help with a question I have aboute the TISE (Sch. tipe indipendent equation). This is a linear equation and linear combination of the solution should be solution too. The problem is that for the free particle, which solution can be written like exp[-ikx], a linear combination using gaussian coefficient is not anymore a solution (we should get a wave pocket this way). Of course taking a combination considering the temporal dipendence give a solution to the TDSE. My question is why that does not appen in the TISE case.
 
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Can you express your question more mathematically? I'm not sure what you are asking.
 
PeroK said:
Can you express your question more mathematically? I'm not sure what you are asking.
I agree. It also sounds like you are trying to model a traveling wave with a time-independent model, which of course will not work.
 
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JackeTheDog132 said:
This is a linear equation and linear combination of the solution should be solution too.
Careful. What you are calling the "TISE" is not a single equation. It is many different equations, one for each different eigenvalue. So the only case where you can form a linear combination of solutions to get another solution is degeneracy, i.e., there are multiple eigenvectors with the same eigenvalue.
 

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