Are coordinate operators Hermitian?

In summary, the coordinate operator is a continuous operator that can be interpreted in the Schrödinger picture. It satisfies the canonical commutation relation and is self-adjoint on its maximal domain of definition. However, understanding it fully requires advanced mathematical concepts such as Rigged Hilbert Spaces and the Generalized Spectral Theorem. It is recommended to first study simpler treatments of quantum theory before delving into the rigorous treatment of the coordinate operator.
  • #1
Heisenberg
2
0
I can't figure this one out given that the coordinate operator is continuous, it's hard to imagine "matrix elements". But presumably since the coordinates of the system (1d free particle) are always real valued, would this make the coordinate operator Hermitian?
 
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  • #2
Coordinate operators make most sense and are to be directly interpreted in the Schrödinger picture, where one builds a representation of the canonical commutation relation [x,p] =ihbar on a Hilbert space. One can show that on the maximal domain of definition, these operators are self-adjoint.
 
  • #3
Sure - its the position operator.

But its not a matrix - it requires Rigged Hilbert Spaces and the Generalized Spectral Theorem to fully flesh out what's going on.

Be warned however the rigorous treatment of such is HARD.

Work your way up to it from Ballentine then a mathematically more orientated treatment like Hall - Quantum Theory For Mathematicians.

Thanks
Bill
 
  • #4
Thanks for the feedback. I appreciate it.
 

1. What does it mean for a coordinate operator to be Hermitian?

A coordinate operator is considered Hermitian if it satisfies the Hermitian property, which states that the operator's adjoint is equal to the operator itself. In simpler terms, this means that the operator's conjugate transpose is equal to the operator itself. This property is important in quantum mechanics, as it ensures that the operator will yield real-valued eigenvalues for its corresponding eigenstates.

2. How can I determine if a coordinate operator is Hermitian?

To determine if a coordinate operator is Hermitian, you can use the Hermitian property mentioned above. Take the operator's adjoint, which is the transpose of its complex conjugate, and compare it to the original operator. If they are equal, then the operator is Hermitian. You can also check if the operator's eigenvalues are real by solving its corresponding eigenvalue equation.

3. Are all coordinate operators Hermitian?

No, not all coordinate operators are Hermitian. For a coordinate operator to be Hermitian, it must satisfy the Hermitian property. If the operator does not satisfy this property, then it is not considered Hermitian. However, many commonly used coordinate operators, such as position, momentum, and angular momentum, are Hermitian.

4. What is the significance of a coordinate operator being Hermitian?

The Hermitian property of a coordinate operator is important in quantum mechanics because it ensures that the operator's corresponding eigenstates will have real eigenvalues. This allows for the physical interpretation of these eigenvalues and their corresponding eigenstates, making it easier to understand and model quantum systems.

5. Can a non-Hermitian coordinate operator still be used in quantum mechanics?

Yes, non-Hermitian coordinate operators can still be used in quantum mechanics. However, they may not have real eigenvalues, making their physical interpretation more difficult. Non-Hermitian operators also do not have the same mathematical properties as Hermitian operators, which may make them less useful in certain applications.

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