Proof that the linear momentum operator is hermitian

In summary, the conversation discusses the proof of whether the linear momentum operator, Px, is hermitian or not. The individual provides their solution, which includes a sign error and a correction. They also mention the need to restrict the wave functions to those that have a certain property and suggest the use of "distributional differentiation." The conversation concludes with confirmation that the solution is acceptable if a special function is used.
  • #1
Paul Black
28
0
hello
i have to proof that Px (linear momentum operator ) is hermitian or not
i have added my solution in attachments

please look at my solution and tell me if its correct


thank you all
 

Attachments

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  • #2
There's a sign error in the last expression of the first page, but you "fixed" it in the next expression.

This looks OK to me, but of course you should explain why ##\left.\psi_b^*\psi_a\right|_{-\infty}^\infty=0##.
 
  • #3
What is the domain of the linear momentum operator that you're looking at? You can't just look at arbirary wave functions, because then ##\psi_b^*\psi_a\vert_{-\infty}^{+\infty}## will not be zero. You need to restrict to special wave function which do have that property.

Another solution is that you use "distributional differentiation".
 
  • #4
thank you for your answers
if i take a special function which satisfy the property then is my solution ok?
 
  • #5
Yea, it looks OK to me.
 
  • #6
ok thank you very much
 

Related to Proof that the linear momentum operator is hermitian

1. What is the linear momentum operator?

The linear momentum operator is a mathematical operator in quantum mechanics that represents the momentum of a particle. It is denoted by the symbol p and is defined as the product of the particle's mass and velocity.

2. What does it mean for an operator to be Hermitian?

An operator is Hermitian if it is equal to its own adjoint, which is the conjugate transpose of the operator. In simpler terms, this means that the operator is real and symmetric.

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

The Hermiticity of the linear momentum operator ensures that it has real eigenvalues, which correspond to physical observables in quantum mechanics. This is crucial for accurately predicting and measuring the behavior of particles.

4. How can we prove that the linear momentum operator is Hermitian?

To prove that the linear momentum operator is Hermitian, we can use the definition of Hermiticity and the commutator relationships between the position and momentum operators. It can also be shown using the fact that the momentum operator is the generator of translations in space.

5. Are there any other important properties of the linear momentum operator?

Yes, the linear momentum operator is also a conserved quantity in quantum mechanics, meaning that it remains constant over time. It is also an important component of the Heisenberg uncertainty principle, which states that the more precisely we know a particle's momentum, the less precisely we can know its position.

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