TeNPy Forum

Thank you very much! I just realized I met the problem because there is Sz conservation in XXZChain. Once I set conserve to None, it works well!

Hi, thank you for your reply! I did use Haar-random state as initial state rather than an eigenstate of Sz when I use exact diagnalization to calculate the time evolution, and this make the Sx and Sy non-zero. May I know how can I get the expectation value of Sx and Sy for random initial state? Than...

Hi, thanks you for your reply! When I try to use exact diagonalization to calculate the time evolution, I find the expectation values of Sx and Sy of the final state are not zero. Also, assume the reduced density matrix of a single site is ([a b],[c,d]), if the expectation values of Sx and Sy are ze...

Hi, I want to calculate the expectation value of Sx, Sy and Sz after TDVP evolution. I use psi.expectation_value('Sx'),psi.expectation_value('Sy'),psi.expectation_value('Sz') to do the calculation but it appears error information: ValueError: <Site, d=2, ops={'Sz', 'Id', 'Sp', 'Sm', 'JW'}> doesn't h...

Hi, I want to calculate the expectation value of Sx, Sy and Sz in the above code after TDVP evolution. I use psi.expectation_value('Sx'),psi.expectation_value('Sy'),psi.expectation_value('Sz') to do the calculation but it appears error information: ValueError: <Site, d=2, ops={'Sz', 'Id', 'Sp', 'Sm'...