Anyons can be used to realize quantum computation, because they are two-level systems in two dimensions. In this paper, we propose a scheme to simulate single-qubit gates and CNOT gate using Abelian anyons in the Kita...Anyons can be used to realize quantum computation, because they are two-level systems in two dimensions. In this paper, we propose a scheme to simulate single-qubit gates and CNOT gate using Abelian anyons in the Kitaev model. Two pairs of anyons （six spins） are used to realize single-qubit gates, while ten spins are needed for the CNOT gate. Based on these quantum gates, we show how to realize the Grover algorithm in a two-qubit system.展开更多
The optical properties of three linear conjugated oligomers （F-P, F-P-F, and P-F-P-F-P）, where phenothiazine （P） and fluorene （F） groups arrange alternately, are investigated. With the enhancement of the π-conj...The optical properties of three linear conjugated oligomers （F-P, F-P-F, and P-F-P-F-P）, where phenothiazine （P） and fluorene （F） groups arrange alternately, are investigated. With the enhancement of the π-conjugated system, their absorption and emission bands both gradually red shift, and their two-photon properties are also improved. Meanwhile, their fluorescence dynamic traces are analyzed with continuous rate distribution model, exhibiting that their decay rates gradually accelerate and the rate distribution width become narrower. The quantum chemical calculation offers their molecular structures and transition mechanism, showing that the enhancement of π-conjugated system should be responsible for tile improvement of two-photon properties.展开更多
Kitaev model has both Abelian and non-Abelian anyonic excitations. It can act as a starting point for topological quantum compu- tation. However, this model Hamiltonian is difficult to implement in natural condensed m...Kitaev model has both Abelian and non-Abelian anyonic excitations. It can act as a starting point for topological quantum compu- tation. However, this model Hamiltonian is difficult to implement in natural condensed matter systems. Here we propose a quantum simulation scheme by constructing the Kitaev model Hamiltonian in a lattice of coupled cavities with embedded A-type three-level atoms. In this scheme, several parameters are tunable, for example, via external laser fields. Importantly, our scheme is based on currently existing technologies and it provides a feasible way of realizing the Kitaev model to explore topological excitations.展开更多
Quantum circuit model has been widely explored for various quantum applications such as Shors algorithm and Grovers searching algorithm.Most of previous algorithms are based on the qubit systems.Herein a proposal for ...Quantum circuit model has been widely explored for various quantum applications such as Shors algorithm and Grovers searching algorithm.Most of previous algorithms are based on the qubit systems.Herein a proposal for a universal circuit is given based on the qudit system,which is larger and can store more information.In order to prove its universality for quantum applications,an explicit set of one-qudit and two-qudit gates is provided for the universal qudit computation.The one-qudit gates are general rotation for each two-dimensional subspace while the two-qudit gates are their controlled extensions.In comparison to previous quantum qudit logical gates,each primitive qudit gate is only dependent on two free parameters and may be easily implemented.In experimental implementation,multilevel ions with the linear ion trap model are used to build the qudit systems and use the coupling of neighbored levels for qudit gates.The controlled qudit gates may be realized with the interactions of internal and external coordinates of the ion.展开更多
A generalization of the geometric measure of quantum discord is introduced in this article, based on Hellinger distance. Our definition has virtues of computability and independence of local measurement. In addition i...A generalization of the geometric measure of quantum discord is introduced in this article, based on Hellinger distance. Our definition has virtues of computability and independence of local measurement. In addition it also does not suffer from the recently raised critiques about quantum discord. The exact result can be obtained for bipartite pure states with arbitrary levels, which is completely determined by the Schmidt decomposition. For bipartite mixed states the exact result can also be found for a special case. Furthermore the generalization into multipartite case is direct. It is shown that it can be evaluated exactly when the measured state is invariant under permutation or translation. In addition the detection of quantum phase transition is also discussed for Lipkin–Meshkov–Glick and Dicke model.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No. 10874098the National Basic Research Program of China under Grant Nos. 2009CB929402, 2011CB9216002the Specialized Research Fund for the Doctoral Program of Education Ministry of China under Grant No. 20060003048
文摘Anyons can be used to realize quantum computation, because they are two-level systems in two dimensions. In this paper, we propose a scheme to simulate single-qubit gates and CNOT gate using Abelian anyons in the Kitaev model. Two pairs of anyons （six spins） are used to realize single-qubit gates, while ten spins are needed for the CNOT gate. Based on these quantum gates, we show how to realize the Grover algorithm in a two-qubit system.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China. （No.21103161. No.11274142, No.11304058, No.11274034. and No.11004080） and the China Postdoctoral Science Foundation （No.2011MS00927 and No.2013T60319）.
文摘The optical properties of three linear conjugated oligomers （F-P, F-P-F, and P-F-P-F-P）, where phenothiazine （P） and fluorene （F） groups arrange alternately, are investigated. With the enhancement of the π-conjugated system, their absorption and emission bands both gradually red shift, and their two-photon properties are also improved. Meanwhile, their fluorescence dynamic traces are analyzed with continuous rate distribution model, exhibiting that their decay rates gradually accelerate and the rate distribution width become narrower. The quantum chemical calculation offers their molecular structures and transition mechanism, showing that the enhancement of π-conjugated system should be responsible for tile improvement of two-photon properties.
基金supported by the National Basic Research Program of China(Grant No. 2009CB929302)the National Natural Science Foundation of China (Grant No. 91121015)+1 种基金the Ministry of Education of China (GrantNo. B06011)the U.S. National Science Foundation (Grant No. PHY-0925174)
文摘Kitaev model has both Abelian and non-Abelian anyonic excitations. It can act as a starting point for topological quantum compu- tation. However, this model Hamiltonian is difficult to implement in natural condensed matter systems. Here we propose a quantum simulation scheme by constructing the Kitaev model Hamiltonian in a lattice of coupled cavities with embedded A-type three-level atoms. In this scheme, several parameters are tunable, for example, via external laser fields. Importantly, our scheme is based on currently existing technologies and it provides a feasible way of realizing the Kitaev model to explore topological excitations.
基金supported by the National Natural Science Foundation of China(Grant Nos.61303039 and 11226336)the Fundamental Research Funds for the Central Universities(Grant No.2682014CX095)the Science Foundation Ireland(SFI)under the International Strategic CooperationAward Grant Number SFI/13/ISCA/2845
文摘Quantum circuit model has been widely explored for various quantum applications such as Shors algorithm and Grovers searching algorithm.Most of previous algorithms are based on the qubit systems.Herein a proposal for a universal circuit is given based on the qudit system,which is larger and can store more information.In order to prove its universality for quantum applications,an explicit set of one-qudit and two-qudit gates is provided for the universal qudit computation.The one-qudit gates are general rotation for each two-dimensional subspace while the two-qudit gates are their controlled extensions.In comparison to previous quantum qudit logical gates,each primitive qudit gate is only dependent on two free parameters and may be easily implemented.In experimental implementation,multilevel ions with the linear ion trap model are used to build the qudit systems and use the coupling of neighbored levels for qudit gates.The controlled qudit gates may be realized with the interactions of internal and external coordinates of the ion.
基金Supported by National Natural Science Foundation of China under Grant No.11005002 and 11475004 New Century Excellent Talent of M.O.E（NCET-11-0937） Sponsoring Program of Excellent Younger Teachers in universities in Henan Province under Grant No.2010GGJS-181
文摘A generalization of the geometric measure of quantum discord is introduced in this article, based on Hellinger distance. Our definition has virtues of computability and independence of local measurement. In addition it also does not suffer from the recently raised critiques about quantum discord. The exact result can be obtained for bipartite pure states with arbitrary levels, which is completely determined by the Schmidt decomposition. For bipartite mixed states the exact result can also be found for a special case. Furthermore the generalization into multipartite case is direct. It is shown that it can be evaluated exactly when the measured state is invariant under permutation or translation. In addition the detection of quantum phase transition is also discussed for Lipkin–Meshkov–Glick and Dicke model.
