Dear Anton Akhmerov,
I want to add magnetic field to a system with 6 electrodes. What gauge should I use? I tried two kinds of gauge. (1) A=(-B*y,0,0); (2) A=(0,B*x,0). But I found the conductance was different for different gauge, which was not reasonable. Can you help to solve this problem?
Best Regards, Zhang Bing
Dear Zhang Bing,
The gauge that is used for each lead _must_ be such that the hoppings are translation invariant for that lead. If you have leads with different directions, this means that you need to use different adopted gauges. It is possible to interpolate between the different gauges using a gauge transformation such that you have the same constant magnetic field vector in all of your system.
Please see footnote 4 and Reference 21 of version 1 of the Kwant paper: http://arxiv.org/abs/1309.2926v1