Theoretical Research On Quantum Information Transport And Non-adiabatic Quantum Computation

Quantum information science is an interdisciplinary subject that applies quantum mechanics to many disciplines such as computer science,information science and cryp-tography,its main research content is relatively safe quantum information transport and reliable quantum computing.In terms of confidentiality and transmission effi-ciency,quantum information has incomparable advantages over classical information.At present,there are many physical carriers for quantum information transport,and the QED system and the interaction of light and matter for quantum information pro-cessing have been extensively studied both theoretically and experimentally.Because of the long life of atoms and photons,it has good anti-decoherence.In particular,the successful development of high-quality factor resonators in recent years has made the cavity QED system one of the most promising candidates for the future practical ap-plication of quantum information processing.Quantum computing can effectively solve some problems that have proved difficult in classical computers,such as the problem of large-scale factorization.In the study of quantum computing,quantum gates are the basic unit for large-scale quantum computing,especially distributed quantum comput-ing.Therefore,constructing and implementing quantum logic gate operations is the core operation of quantum computing,and it is also a necessary condition for realizing quantum computers.In this paper,the effects of dipole-dipole interaction between atoms on single pho-ton transport,fidelity analysis of cyclic three-level system based quantum routing and the construction of general quantum logic gates,and how to achieve high-fidelity non-adiabatic quantum computation in the NV center.The main results and innovations are summarized as follows:1.Coupled-resonator waveguide perfect transport single-photon by the influence of interatomic dipole-dipole interaction.The dipole-dipole interaction is a form of interaction between two atoms.In this scheme,we theoretically investigate single-photon coherent transport in a one-dimensional coupled-resonator waveguide coupled to two quantum emitters with dipole-dipole interactions.The numerical simulations demonstrate that the transmission spec-trum of the photon depends on the two atoms dipole–dipole interactions and the photon-atom couplings.The dipole–dipole interactions may change the dip positions in the spectra and the coupling strength may broaden the frequency band width in the transmission spectrum.We further demonstrate that the typical transmission spectra split into two dips due to the dipole–dipole interactions.2.Fidelity analysis of cyclic three-level system based quantum routing.A quantum router can guide information from one quantum channel to another.Thus,it has an increasingly important role in complex quantum networks in the future.Here,we verify that the quantum router proposed by Zhou.etal.achieves quantum-state high fidelity.We find that when the transition strengths match g_a=g_b,the fidelity of the atom decreases from the maximum value after a period of time and then rises to a maximum value of 1;if the transition strengths do not match,the fidelity will not be able to reach 1.This shows that quantum routers can not only transmit quantum information but also maintain information.3.Quantum iSWAP gate in optical cavities with a cyclic three-level system.To achieve quantum computing,we must construct a universal quantum logic gate,and the iSWAP gate is one of the core units that make up a complex quantum logic gate.Therefore,we have proposed a scheme for one-step implementing iSWAP gate with a cyclic three-level system interacting with a microwave cavity.In this scheme,the interaction of the atomic combination with the strong coupling of the two-cavity mode and the classical field can cause the excited state of the atom to be adiabatically eliminated.Moreover,the scheme is robust against atomic spontaneous emission.We also discuss the influence of the atomic spontaneous emission and the decay of the cavity modes on the photon loss and gate fidelity.The theoretical results show that the scheme has high fidelity under actual noise.4.High-fidelity non-adiabatic holonomic quantum computation on solid-state spins in Nitrogen-Vacancy centers.The high-speed implementation and robustness of non-adiabatic complete quantum computing provides a new way to overcome the difficulty of quantum system and envi-ronment to easily decoherent,which realizing large-scale quantum computer construc-tion.We show that a high-fidelity quantum gates to implement non-adiabatic holonomic quantum computation under electron spin states in Nitrogen-Vacancy centers,providing an extensible experimental platform that has the potential for room-temperature quan-tum computing.Compared with the previous method,we can implement both the one-and two-qubit gates by varying the amplitude and phase of the microwave pulse applied to control the non-Abelian geometric phase acquired by Nitrogen-Vacancy centers.