Quantum computation with three-electron double quantum dots at an optimal operation point

The author analyzes quantum computation with the hybrid qubit (HQ) that is encoded using the three-electron configuration of a double quantum dot. All gate operations are controlled with electric signals, while the qubit remains at an optimal operation point that is insensitive to noise. An effective single-qubit description is derived, and two-qubit interactions are suggested using Coulomb and exchange interactions. Universal quantum control is described and numerically simulated using realistic parameters for HQs in Si and GaAs. High-fidelity quantum computing at the threshold of quantum error correction is possible if the Coulomb interactions between the HQs stay weak.