Optimal control of a charge qubit in a double quantum dot with a Coulomb impurity

D. S. ACOSTA CODEN; R. H. ROMERO; A. FERRÓN; S. S. GOMEZ

PHYSICA E

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 86 p. 36 - 43

1386-9477

We study the efficiency of modulated external electric pulses to produce efficient and fast charge localization transitions in a two-electron double quantum dot. We use a configuration interaction method to calculate the electronic structure of a quantum dot model within the effective mass approximation. The interaction with the electric field is considered within the dipole approximation and optimal control theory is applied to design high fidelity ultrafast pulses in pristine samples. We assessed the influence of the presence of Coulomb charged impurities on the efficiency and speed of the pulses. A protocol based on a two-step optimization is proposed for preserving both advantages of the original pulse. The processes affecting the charge localization is explained from the dipole transitions of the lowest lying two-electron states, as described by a discrete model with an effective electron-electron interaction.