ИСТИНА

Nowadays semiconductor quantum dot units are one of the most promising candidates for the large scale quantum computer. In present work the nonequilibrium diagram technique (NDT), established already in 1964 [1], is applied to the second-quantized model of a semiconductor quantum dots (QDs) system. The localized electron states of arbitrarily connected quantum dots are coupled via quantum tunneling to each other and to 2 conducting electron reservoirs (source and drain) and are also coupled electrostatically to several electrodes (gates). Apart from known analytical solutions [2], the NDT enables comprehensive numerical modeling of electron transport through the QDs in presence of Coulomb repulsion between localized electrons (of Anderson type [3]) with arbitrary voltages supplied to electrodes. In present work, several combinations of numerical optimization algorithms and iterative refinement methods are applied to obtain self-consistent numerical solution of NDT equations determining Green functions for tightly interacting localized electrons. As a result, renormalized multi-electron energy spectrum is revealed; coordinate energy diagrams, IV-curves and charge stability diagrams are presented. Finally, the intrinsic connection between Green functions and reduced density matrix of QDs system is used to determine the level of quantum entanglement between localized electron states and their quantum entropy. 1. L.V. Keldysh "Diagram Technique for Nonequilibrium Processes". JETP, 20, pp. 1018-1026, 1965. 2. N.S. Maslova, P.I. Arseev, V.N. Mantsevich et al. "Quantum interference effects in multi-channel correla-ted tunneling structures". Nature Sci. Rep., 11, № 17676, pp. 1-11, 2021. 3. P.W. Anderson "Localized Magnetic States in Metals". Phys. Rev., 124, pp. 41-53, 1961.