| Information science plays an enormous role in human life and the development of science and technology. However, the existing information system, including computer and communication network, its information function has been opened up close to the limit. In this case, the quantum information science arises. Quantum information science is a new frontier crossed discipline combining with quantum mechanics, computing science and information science, which can accomplish the task that is very difficult to finish in classical computer, besides, has attracted lots of interest in theory and experiment in past decades due to its potential application prospect. So far, quantum information processing can be realized in different physical system, such as linear optics, nuclear magnetic resonance, ion trap, quantum dot and cavity quantum electrodynamics, etc. In the above mentioned programs, cavity quantum electrodynamics scheme is regard as one of the earlier investigation, faster developmental and the most effective schemes in the quantum information field, to date. During my master study, the achievements are summarized as follows:1. We have proposed a scheme to achieve the arbitrary quantum state transfer between two A type three-level atoms based on the atom-cavity-laser system utilizing the adiabatic passage method. If two atoms initially pass through the cavity with the same velocity along the opposite direction, under the common action of the cavity field and laser field, by elaborately adjusting the Rabi frequencies of the laser and the detuning, we can achieve the atomic quantum state transfer successfully and efficiently. It is widely believed that the system unavoidably interacts with the environment in the experimental situation. Thus, we employ the Markov master equation to numerically simulate the dynamical evolution process of the full system in the case of dissipation environment. It shows that the noise reduce the quantum state transfer’s efficiency in some extent according with the experimental fact. Our scheme demonstrates that it is important to rigidly consider the effect of external environment when we employ the adiabatic passage technique for quantum information process, and, it also plays the positive role in the promoting quantum information science’s development.2. We have proposed a scheme to generate controllable photonic Fock state based on the cavity QED system by employing the adiabatic passage technique. In our scheme, when two two-level atoms initially travel through the cavity with the same velocity along the opposite direction, under the common action of the laser field and cavity field, by elaborately adjusting the detuning and the laser’s Rabi frequency, we can achieve the generation of the controllable Fock state with high success rate. By comparing the two photon’s generation with the single photon case, it shows that the generation of two photonic Fock state requires stronger coupling strengths, and that the cavity and atomic dissipation play different roles in the generation of the cavity photons, in which the dissipation could reduce the production of the photon.3. We have proposed a scheme to entangle macroscopic quantum samples based on the hybrid quantum system. In our case, we investigate a hybrid quantum system that consists of two spatially distant quantum dot nuclear spin ensembles interacting with a common nanomechanical resonator, under the collective strong coupling mechanism between the single nuclear spin ensemble and single nanomechanical resonator, and we achieve the macroscopic entanglement between these two nuclear spin ensembles. It shows that a high amount of entanglement between the nuclear spin ensembles can be generated even in the case of considering the nuclear spin ensembles and the nanomechanical resonator’s dissipation. Our scheme can be applied to the entanglement among the multiple nuclear spin ensembles and is of certain theoretical guiding significance to the development of the quantum network. |
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