Angular Momentum and Hamiltonian Commutation

In summary, the task is to prove that the squared angular momentum operator and the Hamiltonian commute in spherical coordinates. This can be achieved by considering the eigenvalues of both operators and understanding how they act on the components of the Hamiltonian. By applying the commutation relation, it becomes apparent that the task is straightforward, although it may seem different at first glance."
  • #1
jtgurkin
1
0
I am working on a problem for homework and am supposed to show that the angular momentum operator squared commutes with H and that angular momentum and H also commute. This must be done in spherical coordinates and everything I see says "it's straightforward" but I don't see it. At least not yet. Can someone help?
 
Physics news on Phys.org
  • #2
I would suggest considering the eigenvalues for both the angular momentum and square of the angular momentum operator. Then think about which parts of either angular momentum (squared or not squared) operator act on the components of the Hamiltonian. Finally, what does the commutation relation tell you about when the operator commutes with the Hamiltonian? I think you should find the problem is actually straight forward, just a little different when you first see it.
 

FAQ: Angular Momentum and Hamiltonian Commutation

1. What is angular momentum?

Angular momentum is a measure of an object's rotational motion. It is defined as the product of an object's moment of inertia and its angular velocity.

2. How is angular momentum related to Hamiltonian commutation?

Angular momentum and Hamiltonian commutation are related through the principle of conservation of angular momentum. This principle states that the total angular momentum of a closed system remains constant, unless acted upon by an external torque. In quantum mechanics, this conservation is expressed through the commutation relations between the angular momentum operators and the Hamiltonian operator.

3. What is the significance of Hamiltonian commutation in quantum mechanics?

Hamiltonian commutation is significant in quantum mechanics because it allows us to determine the energy spectrum of a quantum system. By solving the commutation relations between the Hamiltonian operator and other operators, we can find the allowed energy values of a system.

4. How do angular momentum and Hamiltonian commutation apply to atomic and molecular systems?

In atomic and molecular systems, angular momentum and Hamiltonian commutation play a crucial role in determining the electronic and rotational energy states. The quantum numbers associated with angular momentum, such as the azimuthal quantum number, are used to describe the allowed energy levels of electrons in atoms and molecules. Additionally, the commutation relations between the angular momentum operators and the Hamiltonian operator help to determine the energy levels of molecular rotations.

5. Can angular momentum and Hamiltonian commutation be applied to macroscopic systems?

Yes, angular momentum and Hamiltonian commutation can also be applied to macroscopic systems. In classical mechanics, the angular momentum of a macroscopic object is defined as the product of its moment of inertia and its angular velocity. And in quantum mechanics, the commutation relations between the angular momentum operators and the Hamiltonian operator can be used to describe the energy levels of macroscopic systems, such as spinning objects or rotating molecules.

Back
Top