ITensorChemistry Electron to Fermion Mutual Information Maps

ITensor Julia Questions
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Hi,

I’m using the method that we discussed in [this topic](http

s://itensor.discourse.group/t/mutual-information-matrix/1167) to compute the Mutual Information Maps.

I’ve checked the result obtained by the snippet of code that I’ve implemented, with the GS obtained by ED of the Heisenberg Model Hamiltonian for a 3x3 lattice.
The results are the same.

Now, I’ve moved on the part on which I am more interested, which is Molecular Hamiltonian.
Using ITensorChemistry, I’ve computed some GS of some molecules (H2, H2O, etc) and using the Mutual Information snippet I’ve obtained the Mutual Information Maps.

H2O_sto-3g
H2O_sto-3g700×500 7.71 KB

This are obtained with a MPS in which the sites are Electron, but I would like to have fermionic sites, so instead of N spin orbitals, I’d like to have the MPS as 2N spatial orbitals.

I was looking at the source code and found that I can pass the sitetype = “Fermion”/“Qubit” and obtained the desired MPS as fermions.
Computing the MI map, I’ll obtain the following map

H2O_sto-3g_fermio
H2O_sto-3g_fermio700×500 8.66 KB

So, the question is In the mapping from Electron to Fermion, the final position of spatial orbitals will be up,down,up,down,… , right? Or, Am I misunderstanding this part of the code?

Is there a way to place all the up spatial orbitals in the first N sites and down orbitals in the second group of N sites?

Best,
Fabio.