Controlled high-fidelity navigation in the charge stability diagram of a double quantum dot

Abstract

We propose an efficient control protocol for charge transfer in a double quantum dot. We consider numerically a two-dimensional model system, where the quantum dots are subjected to timedependent electric fields corresponding to experimental gate voltages. Our protocol enables navigation in the charge stability diagram from a state to another through controllable variation of the fields. We show that the well-known adiabatic Landau-Zener transition -when supplemented with a time-dependent field tailored with optimal control theory -can remarkably improve the transition speed. The results also lead to a simple control scheme that requires only a single parameter obtained from the experimental charge stability diagram. Eventually, we can control the system at the fastest speed allowed by the quantum dynamics and with a high fidelity.

Fast optical control of a coded qubit in a triple quantum dot

“…the ability to change the quantum state of the system in a reliable and repetitive way with a very high fidelity is most stringent. In recent years there has been an increasing interest in controlling quantum phenomena in molecular systems and nanodevices [10][11][12][13][14][15][16][17][18]. The coherent quantum control of electrons in quantum dots exposed to electromagnetic radiation is of great interest, not only in quantum information processing but in many technological applications as charge transport devices [19][20][21].…”