IV curve of a single Josephson junction

[sabinomaggi]

To learn how to use superconductor I am trying to calculate the IV curve of a single Josephson junction. The best I have been able to do so far is:

CIRC_initialize();
add_JJ("J0", 0, 1, 1.0, 1.0);
add_JJ("JJ", 1, 2, 0.4, 0.25);
add_CS("IDC", 2, 0, 0.1);
add_R( "R0", 1, 0, 1.0);

CIRC_STEPT=0.1;
CIRC_build_trees();

t=new_buffer();
graph(t);
set_flush(t,0);

ICSTEPS=100;
ICAMP=PI*2.0;

INTT=800.0;

IVAMP=1.0;
IV("JJ","IDC",t);
IVAMP=-1.0;
IV("JJ","IDC",t);

write_all("iv");
exit(0);

where I get this (as expected):

I cannot avoid to have a second JJ (J0) + R0 in series with the real juntion, which should act as a control source. Inserting a real current/voltage source does not work, as soon as JJ switches to the 0 voltage state, you get +/- nan for the voltage across the junction.

[adewes]

Thanks for this @sabinomaggi , I'll have a look at it these days and add some examples.