Spinless fermions tutorial

[afeiguin]

Besides spin chains, it would be nice to have more examples with fermions (for ED and DMRG)

[marcusr2ML]

@afeiguin Did you have a specific model in mind? Like Heisenberg XXZ model mapped to spinless Fermion Hamiltonian via JW transform? Or some sort of t-J model using Abrikosov Fermions? etc.

[Ooolab]

I will work on this model today and create an initial version of the tutorial. If anything extra needs to be added (from @afeiguin ), we can always update it later. So, give me a day or two.

[marcusr2ML]

@Ooolab I am already writting an introduction mapping the XXZ Heisenberg model to interacting spinless fermions using JW. Could you work on the next stage of this?

[Ooolab]

@marcusr2ML Ok. To be clear, you added me to a forked branch yesterday. Are you using that branch to work on the spineless fermion tutorial? I will check that branch for your updates.

[marcusr2ML]

@Ooolab I just updated my branch. I did an introduction detialing JW and how spin became a U(1) symmetry. I might trim it down.

Also adding in a few tutorials for finding GS energy. I'm not too invested in these, so deleting/reconfiguring them if there is overlap is fine.

[Ooolab]

I added a simulation page to your branch. Please check. Anything to be changed?

[marcusr2ML]

@Ooolab We made the same simulations, more or less.

I kept your module as is. I decided to add supplements: open vs closed BC and spinless fermoins vs hardcore bosons. These illustrate some assertions made in the text. Also added a module on diagonlizing based off particle number sector.