Multiple two-qubit operations for a coupled semiconductor charge qubit

We investigate functional two-qubit operations in coupled semiconductor charge qubits, where two spatially separated electrons are coherently excited. Their time-evolutions are investigated for an ideally closed system as well as for a realistic semiconductor device with some decoherence and dephasing processes. We find various types of quantum operations can be performed each in a single step just by adjusting the energy biases of the two qubits. These operations are promising for generating strong quantum correlation between spatially separated electrons.