Dear forum,

I want to check if the ground state returned by DMRG is identical to the valence bond ground state of the AKLT model

( https://en.wikipedia.org/wiki/AKLT_model ).

For this purpose, I need to project a pair of spin-1/2 particles on adjacent sites onto the spin-1 (or triplet) subspace using the projection operator as shown on the following link

https://1drv.ms/u/s!ApS6tTYbSmDBjFXFmQdES0QnV7yw

where the symbols “+”, “0” and “−” label the standard spin-1 basis states.

I have been able to construct the first and last terms of this operator using the pre-built operator “Proj” discussed on the webpage http://itensor.org/docs.cgi?page=classes/siteset but I have not been able to construct the second term (the one with |0>). Could you please help me? Thanks in advance.

Regards,

Niraj