Nonlinear transport through quantum dot studied by the time-dependent DMRG

Nonequilibrium transport properties of quantum dot under a finite bias voltage is investigated using the adaptive time-dependent density matrix renormalization group (TdDMRG) method. The validity of the authors’ previous study was limited for relatively weak coupling parameters because the small scale Kondo energy in the strong coupling regime caused a difficulty. By taking sufficiently long system size, keeping large number of states during the TdDMRG process and utilizing the fourth order Suzuki–Trotter decomposition, we can extend calculations of current–voltage characteristics in the strongly correlated region up to the Wilson ratio RW<1.97, close to the strong coupling limit. The wide domain of applicability suggests future applications of the method to various nonequilibrium and time-dependent problems.