Hello,

I am trying to obtain the ground state of a Hubbard model (I am adapting the "exthubbard" example) where the hopping terms are given by

for(int b = 1; b < N; ++b)

{

ampo += -t1*exp(ii*(-0.5)*chi),"Cdagup",b,"Cup",b+1;
ampo += -t1*exp(ii

*(+0.5)*chi),"Cdagup",b+1,"Cup",b;

ampo += -t1

*exp(ii*(+0.5)

*chi),"Cdagdn",b,"Cdn",b+1;*

ampo += -t1exp(ii

ampo += -t1

*(-0.5)*chi),"Cdagdn",b+1,"Cdn",b;

}

where

ii is the imaginary constant, and chi and t1 are real constants.

The initial wavefunction MPS is given like in the example (Neel state). Upon running I get

libc++abi.dylib: terminating with uncaught exception of type std::runtime_error: Error condition in diagHermitian

Is there any change I should make to the MPOs to allow for these complex numbers?

Best regards,

Rafael