On Mar 14, 2013, at 7:00 AM, Chen Ahai chenahaiphysics@gmail.com wrote:
Dear all,
I am trying to add the spin-orbit coupling term to the 1D Hubbard model. I use the standard files for 1D Hubbard model in the library and add those codes:
<BONDOPERATOR name="SOC" source="x" target="y"> cdag_up(y)*c_down(x)-cdag_down(y)*c_up(x)+cdag_down(y)*c_up(x)-cdag_up(y)*c_down(x) </BONDOPERATOR> ----------------------------------------------------------------------------------- and ----------------------------------------------------------------------------------- <BONDTERM source="i" target="j"> <PARAMETER name="t#" default="0"/> <PARAMETER name="alpha" default="0"/> -t*fermion_hop(i,j)-alpha*SOC(i,j) </BONDTERM> ----------------------------------------------------------------------------------- to the model XML file just like before. But it seems it does not work. The results keep the same when I change the parameter 'alpha' .
Can you give me some advices ? Thank you very much in advance.
As usual, without full inputs and scripts nobody will be able to really tell you what is happening. My conjecture is that you have declared Sz as a conserved quantum number, and then this term actually never acts.