Hi,

I am not sure if kwant can really compute supercurrent in JJ. I think kwant superconducting simulation does not compute pairing potentials self-consistently. As such, the current continuity condition is not guaranteed and the current is not accurate.  I would suggest that you first plot current as a function of position (in 1D or 2D or whatever geometry you are considering) to see if the continuity condition is satisfied.


Best,

Amrit


On Wed, Jun 17, 2020 at 8:51 AM <mohit.gupta9607@gmail.com> wrote:
Dear Abbout,
I apologize for not being clear in my question. My system is infinite (that is there are leads attached to the system) and I mounted virtual leads at points where I wanted kwant to evaluate green's function. Sorry about that.

The formula that I am using is from the supplementary material of the following  paper:
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.047702
It is possible that I am misinterpreting the formula as given in the paper as am very new to the subject.

I want to evaluate critical current in the Josephson Junction by maximizing current-phase dependency, for that I need total current in the system as a function of phase difference phi, I am not sure how to do that with local current operator in kwant.

Thank you for clarifying the output of green's function I am now sure that I was reading the output wrong which must have been the primary reason for getting zero.

I again apologize if I am not clear about what I am saying.