A Modular Method for the Efficient Calculation of Ballistic Transport Through Quantum Billiards

We present a numerical method which allows to efficiently calculate quantum transport through phase-coherent scattering structures, so-called “quantum billiards”. Our approach consists of an extension of the commonly used Recursive Green’s Function Method (RGM), which proceeds by a discretization of the scattering geometry on a lattice with nearest-neighbour coupling. We show that the efficiency of the RGM can be enhanced considerably by choosing symmetry-adapted grids reflecting the shape of the billiard. Combining modules with different grid structure to assemble the entire scattering geometry allows to treat the quantum scattering problem of a large class of systems very efficiently. We will illustrate the computational challenges involved in the calculations and present results that have been obtained with our method.