Study On The Mechanism Of Rabi Oscillation In QPC Measurement

Electronic spin can be used as a qubit in quantum communication due to the advantages of long coherence time and easily operated. Interaction between the electronic spin and the environment can cause the decoherence, which lead to the quantum noise. Quantum point contact(QPC) can be used as a detector to measure the decoherence mechanism of the single charge state in the quantum dots model. The main content includes the effects of decoherence and local field correction(LFC) on the Rabi oscillation in QPC measurement.Our research jobs are as follows:1.By theoretical simulation, the quantum dots system in dense medium is simplified to be a two level system. Based on the phenomenological theory, the QPC which is introduced as a detector is used to measure the decoherence mechanism of the single charge state in our research of the effects of decoherence on Rabi oscillation in the quantum dots system. Two factors are considered in the results.We simulate the Rabi oscillation of the electronic spin states for the system asymmetric qubit being zero and the tunnel energy with the effect of decoherence. We found that the Rabi oscillation changes from equal amplitude period to periodic decay oscillation when the asymmetric qubit is zero and the amplitude changed into alternately periodic decay oscillation when the asymmetric qubit reach tunnel energy.2. We also investigate the effect of Local field correction on Rabi oscillation states in quantum dots system. Meanwhile,we research the electronic spin states with the local field correction increased gradually in the case of different system asymmetric qubit. We found that the frequency of Rabi oscillation increased fast when the local field increased.