Local measurement of the entanglement between two quantum-dot qubits

Using the modified rate equation the local measurement of the entanglement between two quantum-dot qubits, with two isolated quantum-point-contact detectors, is investigated. It is shown that the measurement process will induce the decaying of the two-qubit entanglement, as well as the electron-occupation probabilities. Furthermore, we find an effective scheme to measure the two-qubit entanglement based on the local measurement. It is demonstrated that the entanglement between the two qubits coupled by the strong Coulomb interaction can be fully extracted according to the time-dependent variation rate of the detector current.