How to compute expectation values guide, issue #473

[esraayantuna]

Added a Jupyter notebook explaining how to compute expectation values with ffsim.

[esraayantuna]

Hi @0sophy1! Can you review this PR, please?

[0sophy1]

Hi @0sophy1! Can you review this PR, please?

Thank you so much for this awesome work Esra,

I found these 5 expectation functions

state.spin_square
reduceDensityMatrix.expectation
expectation_one_body_product
expectation_squared_diag_coulomb
SingleFactorizedHamiltonian.expectation_product_state

and wonder if these are also good to be added to this guide.

@kevinsung Your input will be very helpful and valuable!

[kevinsung]

Hi @0sophy1! Can you review this PR, please?

Thank you so much for this awesome work Esra,

I found these 5 expectation functions

state.spin_square reduceDensityMatrix.expectation expectation_one_body_product expectation_squared_diag_coulomb SingleFactorizedHamiltonian.expectation_product_state

and wonder if these are also good to be added to this guide.

@kevinsung Your input will be very helpful and valuable!

No, we shouldn't mention those functions. This guide should only show how to get expectation values with Scipy LinearOperator and np.vdot. I will review this PR (hopefully soon).

[0sophy1]

Hi @0sophy1! Can you review this PR, please?

Thank you so much for this awesome work Esra,
I found these 5 expectation functions
state.spin_square reduceDensityMatrix.expectation expectation_one_body_product expectation_squared_diag_coulomb SingleFactorizedHamiltonian.expectation_product_state
and wonder if these are also good to be added to this guide.
@kevinsung Your input will be very helpful and valuable!

No, we shouldn't mention those functions. This guide should only show how to get expectation values with Scipy LinearOperator and np.vdot. I will review this PR (hopefully soon).

Thank you @kevinsung ! I believe this tutorial meets your expectations.

[kevinsung]

Thanks Esra!

• The notebook file should go in docs/how-to-guides/. Also, the filename should use hyphens - instead of underscores _.
• Add a title and format the notebook to use traditional Markdown headings
• Use MolecularHamiltonian instead of DiagonalCoulombHamiltonian
• Only using the diagonal is not a valid method, it only worked because you created a diagonal Hamiltonian.