A Direct Measurement Scheme of Two Quantum-Dot Qubits Quantum Correlation via Detector Current

By using the rate equation method we have investigated a scheme for measuring the quantum discord between two double quantum dot qubits via the current in quantum point-contact devices. The current of the detectors is same in-phase as the time-dependant of the quantum discord, and we can read out the most important time point when the quantum discord or quantum correlation reaches its maximum or minimum. Furthermore, in a special initial condition, the current can reflect the quantum discord. The shot noise of the detectors is calculated numerically. Which is dominated by the measured signal in single shot experiments.