Hi Miles,

I have a question regarding the MPS in infinite DMRG calculations. When trying to compute the expectation of an operator O, there are two ways of contracting the edge indices, as shown in the figure (please forgive my drawing..)

I think the lower one makes more sense, by definition of MPS, but the upper one is used in the sample codes. Also, the two methods give close but not exactly equal numerical results. Can you explain a little about the (in)equivalence thereof? Thanks!

Best,

Chengshu

Additional "experimental" fact