Variations of the Bipartite Entanglement in a Metal Nanosphere Plasmonic Environment

• Main Authors: Wan-Yu Liu, 劉宛育
• Other Authors: 陳光胤
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/50231789744657171170

碩士 === 國立中興大學 === 物理學系所 === 105 === The metal surface, in general, contains infinite modes of free-charge oscillation, and thus causes dissipations to the quantum system coupled to it. However, recent studies have shown that as a two-level system is positioned very close to the metal surface, the strong coupling between them will change the spectral density of surface-plasma fields from smooth to structured. This can lead to different dynamics of that quantum system from purely exponential decay. In this thesis, we therefore investigate the variations of excitonic dynamics and bipartite entanglement of the double two-level systems which are placed close to the metal surface. We apply the Master equation to compute the density matrix of the system, and then calculate the entanglement dynamics. We find that the entanglement can be revival due to quantum interference for both the initial state being in one of the two-level systems or in entangled state. The results show that the structured surface-plasmon-field environment can not only play a role of pure dissipations but help to protect the quantum coherence of the system coupled to it.