Show that Momentum Operator is Hermitian: Q&A

In summary, the task is to show that the momentum operator is hermitian and a link has been found to help solve the problem. However, there are two steps that the person doesn't understand and requires clarification. The definition of hermitian is known, but there is uncertainty on how it applies to the specific situation. It is suggested to start with understanding what it means for an operator to be the same as its complex conjugate and how it relates to inner products.
  • #1
krootox217
51
2

Homework Statement


Hi, my task is to show that the momentum operator is hermitian.

I found a link, which shows how to solve the problem:

http://www.colby.edu/chemistry/PChem/notes/MomentumHermitian.pdf

But there are two steps that I don't understand:

1. Why does the wave function approach zero for long distances (for a confined particle)? Can someone explain me this?

2. I don't understand the last step. I got
xMHR6K1.png


And now i don't know how to use the last equation on the paper to show that it is the same.

Can someone help me?

Homework Equations


See above

The Attempt at a Solution


See above[/B]
 
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  • #2
Do you know the definition of hermitian?
 
  • #3
I know what a hermitian matrix is. But here I'm not sure. I guess that the operator is the same as the complex conjugate of the operator?
 
  • #4
You should start there then. There's no need to guess. The definition should be explained on your textbook or notes. You want to figure out specifically what it means when you say an operator is the same as its complex conjugate. It's probably explained in terms of inner products.
 

1. What is the definition of a Hermitian operator?

A Hermitian operator is a linear operator that is equal to its own adjoint. In other words, the operator is equal to its complex conjugate transpose.

2. Why is it important for the momentum operator to be Hermitian?

A Hermitian operator is important because it has real eigenvalues and its eigenvectors form a complete set. This allows for the easy calculation of expectation values and for the operator to be used in quantum mechanics.

3. How do you show that the momentum operator is Hermitian?

To show that the momentum operator is Hermitian, we need to show that it is equal to its own adjoint. This can be done by using the definition of the momentum operator and its adjoint, and then showing that they are equal through algebraic manipulation.

4. Can you explain why the momentum operator is not Hermitian in classical mechanics?

In classical mechanics, the momentum operator is not Hermitian because it does not have complex eigenvalues. This is because classical mechanics deals with real-valued quantities, while quantum mechanics deals with complex-valued quantities.

5. How does the Hermiticity of the momentum operator relate to the conservation of momentum?

The Hermiticity of the momentum operator is related to the conservation of momentum because the eigenvalues of a Hermitian operator correspond to observable quantities. In this case, the eigenvalues of the momentum operator represent the possible values of momentum, which is conserved in a closed system.

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