TeNPy Forum

Hello everyone,
I have a simple question (I guess). I'm trying to find the expectation value of the number operatore using the BH model but I'm really stuck. Does anyone know how to do it? Thanks!

I assume you mean the Bose Hubbard model?
In what state do you want to take the expectation value?
If you want it in the groundstate, you can take an MPS psi resulting from DMRG and use
psi.expectation_value('N'), which gives you the particle number on every single site.

Hello, thanks for your reply.
Yes, I meant in the ground state! What would be the complete code line?

Have a look at these examples that simulate groundstate expectation values
https://tenpy.readthedocs.io/en/latest/ ... _dmrg.html