Conservation of Spin Parity (Fermion parity in fermion langage)


I have a question about conducting DMRG with fixed symmetries using ITensor. I am currently working on a system with “S=1/2”, where the sum of Sz is not conserved and there is no U(1) symmetry, but the parity (even or odd) of the PRODUCT of Sz is preserved as a Z_2 parity symmetry. This corresponds to fermion parity when performing a Jordan-Wigner transformation. However, despite some research, I have not been able to find a method to perform DMRG under these conditions and calculate the expectation values of certain quantities. Is there a way to achieve this?

Thank you for your assistance.