How Do You Write the Hamiltonian in the Basis |\theta>?

In summary, the conversation discusses the expression for the Hamiltonian in the basis of |\theta>, given by H = \frac{2e^2}{\hbar^2 C} \hat{p^2} - \frac{\hbar}{2e} I_c cos\hat\theta , where [\hat\theta , \hat{p}] = i \hbar and the attempt at a solution involves converting the expression into the basis form using the Laplace operator in spherical polar coordinates.
  • #1
TeddyYeo
4
0

Homework Statement



[itex] H = \frac{2e^2}{\hbar^2 C} \hat{p^2} - \frac{\hbar}{2e} I_c cos\hat\theta [/itex],
where [itex] [\hat\theta , \hat{p}] = i \hbar[/itex]
How can we write the expression for the Hamiltonian in the basis [itex] |\theta> [/itex]

Homework Equations

The Attempt at a Solution



I have already solved most part of the question and this is just one part of it that I am not sure how to convert into the basis form.
Is it that I just now need treat
[itex] \hat{p}] = -i \hbar ∇ which is means that it is -i \hbar frac{\partial }{ \partial \theta}[/itex]
and put
[itex] H = \frac{2e^2}{C} \frac{\partial^2}{\partial\theta^2} - \frac{\hbar}{2e} I_c cos\hat\theta [/itex]
then this is the final form??
 
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  • #2
Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
 
  • #3
TeddyYeo said:

Homework Statement



[itex] H = \frac{2e^2}{\hbar^2 C} \hat{p^2} - \frac{\hbar}{2e} I_c cos\hat\theta [/itex],
where [itex] [\hat\theta , \hat{p}] = i \hbar[/itex]
How can we write the expression for the Hamiltonian in the basis [itex] |\theta> [/itex]

Homework Equations

The Attempt at a Solution



I have already solved most part of the question and this is just one part of it that I am not sure how to convert into the basis form.
Is it that I just now need treat
[itex] \hat{p}] = -i \hbar ∇ [/itex] which is means that it is [itex] -i \hbar frac{\partial }{ \partial \theta}[/itex]
No. ##\hat{p^2}=-i \hbar ∇(-i \hbar ∇) =-h^2 \Delta##. Use the Laplace operator written in spherical polar coordinates.
 

FAQ: How Do You Write the Hamiltonian in the Basis |\theta>?

What is the purpose of writing Hamiltonian in the basis?

The Hamiltonian is a mathematical operator that describes the total energy of a system. Writing it in a specific basis allows us to understand how the system's energy is distributed among its different states. It also helps us solve the Schrödinger equation and predict the system's future behavior.

How do you write the Hamiltonian in a specific basis?

To write the Hamiltonian in a basis, we first need to express the basis states as a linear combination of the eigenstates of the Hamiltonian. Then, we use the matrix elements of the Hamiltonian to transform the basis states into the eigenstate basis. This allows us to write the Hamiltonian as a matrix in the new basis.

What is the difference between writing the Hamiltonian in the position basis and the momentum basis?

The position basis and the momentum basis are two different sets of basis states that can be used to write the Hamiltonian. In the position basis, the basis states are the different positions of the system, while in the momentum basis, the basis states are the different momenta of the system. The matrix elements of the Hamiltonian will be different in these two bases, resulting in different equations of motion for the system.

Can we always write the Hamiltonian in a specific basis?

Yes, we can always write the Hamiltonian in a specific basis. However, the choice of basis may not always be the most convenient for solving a particular problem. In some cases, it may be more beneficial to use a different basis that simplifies the equations of motion or reveals certain physical properties of the system.

What are the advantages of writing the Hamiltonian in a basis?

Writing the Hamiltonian in a basis allows us to better understand the energy distribution and dynamics of a system. It also simplifies the mathematical calculations involved in solving the Schrödinger equation and predicting the system's behavior. Additionally, it can reveal certain symmetries and physical properties of the system that may not be apparent in other representations.

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