Dear Kamal, It appears that your questions mostly relate to the background physics knowledge and are not specific to Kwant. There is vast literature explaining how quantum transport works, and it provides a much more detailed and systematic answer to your questions than this mailing list can do. Best regards, Anton Akhmerov On Fri, Oct 28, 2016 at 12:44 PM, kamal ghosh wrote:

Hi all, Many thanks to all the developers of kwant not only for the strong potential development of the code but very specially also for the help to solve coding and related physics problems. Presently, I am wondering how to calculate current in a device, say a QWR, connected to source and drain through two infinite leads! Applying the Landauer relation, I require no. of channels M upto the level of Fermi and Transmission probabilities per channel. To me, this appears very involved programming; because (i) first to find the Fermi first and next to find the no. of channels below that (ii) secondly, for any channel the all energies upto the Fermi I have to calculate and (iii) finally to sum up. Then we may get the total transmission probability. I am not sure that is it right to think of a constant probability in a particular channel? I think it is "no". However, I noticed a tutoring correspondence from Joe and Akhmerov in a correspondence with an user working with calculating the current like me. I could not understand the solution because current carried by scattering state is written by a code which I am afraid how to write that code in high level python text? Please, bear with me on this trifling matter. Should we wait for the version kwant2? All the best wishes and awaiting your wise advise. K.K.Ghosh