Laser-induced operations with charge qubits in a double-well nanostructure

TL;DR

This paper investigates laser-driven charge qubit operations in a double quantum dot system, identifying optimal laser tuning strategies and providing analytical and numerical results for quantum gate implementation.

Contribution

It introduces a theoretical approach to optimize laser-induced charge qubit operations in double quantum dots, including pulse parameter determination for quantum gates.

Findings

Optimal laser frequency tuning between excited states enhances operation fidelity.

Analytical results agree with numerical simulations.

Pulse parameters for quantum NOT operation are specified.

Abstract

We present the results of theoretical studies on operations with charge qubits in the system composed of two tunnel-coupled semiconductor quantum dots whose two lowest states (localized in different dots) define the logical qubit states while two excited states (delocalized between the dots) serve for the electron transfer from one dot to another under the influence of the laser pulse. It is shown that in the case of small energy separation between the excited levels, the optimal (from the viewpoint of minimal single-qubit operation time and maximum operation fidelity) strategy is to tune the laser frequency between the excited levels. The pulse parameters for implementation of the quantum NOT operation are determined. Analytical results obtained in the rotating-wave approximation are confirmed by rigorous numerical calculations.