Dear all,
I have an inhomogeneous lattice problem and I try to measure a "local" bondoperator, e.g., the current over one bond only. I get the following error from the sparsediag application
Did not parse to end of string '(one-bond)/4(i)'
when I try to do a "MEASURE_AVERAGE". I get no error if I use "MEASURE_LOCAL". I am a bit puzzled that "MEASURE_LOCAL" does something all together as my operator contains more than one site, which is in violation to a condition on local measurements on the alps webpage. I paste a minimal (silly) set of configuration files which produces this error below. Help would be greatly appreciated.
Sebastian
lanczosconf:
MODEL="simple"; LATTICE="2x2" LATTICE_LIBRARY="graph.xml" MODEL_LIBRARY="model.xml" COMPLEX=true; t=-1; Nup_total=1; Ndown_total=1; CONSERVED_QUANTUMNUMBERS="N,Sz"; NUMBER_EIGENVALUES=2; TRANSLATION_SYMMETRY=false; MEASURE_AVERAGE[one-bond]=one-bond; {U=1;}
graph.xml:
<LATTICES>
<GRAPH name="2x2" dimension="2" vertices="4" edges="9"> <VERTEX id="1" type="0"><COORDINATE>0 0</COORDINATE></VERTEX> <VERTEX id="2" type="0"><COORDINATE>1 0</COORDINATE></VERTEX> <VERTEX id="3" type="0"><COORDINATE>0 1</COORDINATE></VERTEX> <VERTEX id="4" type="0"><COORDINATE>1 1</COORDINATE></VERTEX> <EDGE source="1" target="2" id="1" type="1" vector="1 0"/> <EDGE source="2" target="1" id="2" type="2" vector="1 0"/> <EDGE source="3" target="4" id="3" type="3" vector="1 0"/> <EDGE source="4" target="3" id="4" type="4" vector="1 0"/> <EDGE source="1" target="3" id="5" type="5" vector="0 1"/> <EDGE source="2" target="4" id="6" type="6" vector="0 1"/> <EDGE source="3" target="1" id="7" type="7" vector="0 1"/> <EDGE source="4" target="2" id="8" type="8" vector="0 1"/> <EDGE source="1" target="4" id="9" type="9" vector="1 1"/> </GRAPH>
</LATTICES>
model.xml
<MODELS> <SITEBASIS name="fermion"> <QUANTUMNUMBER name="Nup" min="0" max="1" type="fermionic"/> <QUANTUMNUMBER name="Ndown" min="0" max="1" type="fermionic"/> <OPERATOR name="Splus" matrixelement="1/2"> <CHANGE quantumnumber="Nup" change="1"/> <CHANGE quantumnumber="Ndown" change="-1"/> </OPERATOR> <OPERATOR name="Sminus" matrixelement="1/2"> <CHANGE quantumnumber="Nup" change="-1"/> <CHANGE quantumnumber="Ndown" change="+1"/> </OPERATOR> <OPERATOR name="Sz" matrixelement="(Nup-Ndown)/2"/> <OPERATOR name="Nup" matrixelement="Nup"/> <OPERATOR name="Ndown" matrixelement="Ndown"/> <OPERATOR name="c_down" matrixelement="1"> <CHANGE quantumnumber="Ndown" change="-1"/> </OPERATOR> <OPERATOR name="cdag_down" matrixelement="1"> <CHANGE quantumnumber="Ndown" change="1"/> </OPERATOR> <OPERATOR name="c_up" matrixelement="1"> <CHANGE quantumnumber="Nup" change="-1"/> </OPERATOR> <OPERATOR name="cdag_up" matrixelement="1"> <CHANGE quantumnumber="Nup" change="1"/> </OPERATOR> <OPERATOR name="n" matrixelement="Nup+Ndown"/> <OPERATOR name="n_up" matrixelement="Nup"/> <OPERATOR name="n_down" matrixelement="Ndown"/> </SITEBASIS>
<BASIS name="fermion"> <SITEBASIS ref="fermion"/> <CONSTRAINT quantumnumber="Nup" value="Nup_total"/> <CONSTRAINT quantumnumber="Ndown" value="Ndown_total"/> </BASIS>
<BONDOPERATOR name="one-bond" source="1" target="2"> I*(cdag_up(1)*c_up(2)-cdag_up(2)*c_up(1)) </BONDOPERATOR>
<HAMILTONIAN name="simple"> <PARAMETER name="U" default="1"/> <BASIS ref="fermion"/> <SITETERM site="i"> U*n_up(i)*n_down(i) </SITETERM> </HAMILTONIAN>
</MODELS>