Singie Photon Transport Properties In Dissipative Coupled Cavity Arrays

The experimental progresses in fabricating large-scale arrays of high-quality cavities and in engineering strong interaction of photon and atom make the potential application of the coupled cavity arrays(CCAs) to real-ize quantum simulators. People looks forward to that it can be helpful to realization of quantum simulator in the quantum computers and quantum information. Photon travels at the speed of light in vacuum and medium with little decoherence, so it’s faithfully used in quantum information pro-cessing. Controllable single photon transport in coupled cavity arrays has attracted much attention in both theoretical and experimental studies due to its potential applications in quantum information processing. There-fore, many proposals have been put forward to realize quantum switches for control single photon transport in coupled cavity array.Despite the substantial progresses, a number of issues still exist. The system is usually investigated under the ideal condition. However, a re-alistic system can rarely be isolated from its environment completely. In general, the coupling to the environment will result in dissipation, deco-herence and entanglement. In the process of the single photon transports, the environment could induce an inelastic scattering because of the non-conservation of the energy of the incident photon, which would affect the photon transmission and reflection amplitudes and reduce the quantum switching in different ways.Here, we describe the new quasi-boson approach and derive the ef-fective Hamiltonian for the dissipative coupled cavity system. Its entity is to eliminate the coordinates of the baths and redescribe the dissipative scheme using an effective Hamiltonian, and then an analytical result can be obtained. We used the quasi-boson method to study three different models. In section2, we analyzed the effects of dissipations on the single photon transport in the coupled cavity arrays, with one of the cavities coupled to a two-level atom. It is shown that when an atom cavity is in tune, the atomic dissipation has a stronger effect on the single photon transmission amplitude than that the cavity dissipation does around the resonance area. When the atom and the cavity are large detuned, the dissipation of the cavity has a stronger effect on the single photon transmission amplitude; dissipations lower the peak of the single photon transmission. In section3, we discussed the single photon transport in a coupled cavity array where one of the cavities is coupled to the A-type, V-type and (?)-type three-level atoms, respectively. A more advanced single photon switch can be ob-tained. In addition, we studied the impact of the dissipations of the atom and the cavities on the single-photon transmission spectrum in particular. In section4, we investigated the effects of dissipation on the behavior of the single photon transport in the system of the coupled cavity arrays, with two nearest cavities nonlocally coupled to a two-level atom. We stud-ied two different situations of local and nonlocal couplings, respectively. Comparing the dissipative case with the nodissipative one, it reveals that the dissipation of the system increases the middle dip and lowers the peak of the single photon transmission amplitudes, and broadens the line width of the transport spectrum. It should be noted that the influence of the cavity dissipation to the single photon transport spectrum is asymmetric. Whereas in the nonlocal coupling case, when the coupling strength gets stronger, the cavity dissipation has a greater effect on the single photon transport spectrum, and the atom dissipation affection becomes weak, it can be ignored. Finally, conclusions and an outlook of this thesis are pre-sented in the last part.