add_multi_coupling vs. GroupedSite
Posted: 23 May 2022, 04:37
Hello,
I have a unit cell with 2 FermionSite and I would like to implement a term like
\(c^\dagger_{0, n+1}c^\dagger_{1, n+1}c_{1, n}c_{0, n}\),
where 0 and 1 are the sublattice indices and n runs over the unit cells.
So something like a two-body hopping term (or can be thought of as a nearest neighbor Coulomb interaction as well, I guess.
I probably can't use CouplingModel.add_coupling to do this, because there I can only provide two local operators, whereas I need four.
There's also the CouplingModel.add_multi_coupling method, however I wonder whether I should rather just build a GroupedSite instead.
What are the pros and cons of the two approaches and are both suitable for my Hamiltonian?
Thank you very much.
I have a unit cell with 2 FermionSite and I would like to implement a term like
\(c^\dagger_{0, n+1}c^\dagger_{1, n+1}c_{1, n}c_{0, n}\),
where 0 and 1 are the sublattice indices and n runs over the unit cells.
So something like a two-body hopping term (or can be thought of as a nearest neighbor Coulomb interaction as well, I guess.
I probably can't use CouplingModel.add_coupling to do this, because there I can only provide two local operators, whereas I need four.
There's also the CouplingModel.add_multi_coupling method, however I wonder whether I should rather just build a GroupedSite instead.
What are the pros and cons of the two approaches and are both suitable for my Hamiltonian?
Thank you very much.