This paper introduces two types of two-mode excited entangled coherent states （TMEECSs） ψ±（（α,m,n））, studies their entanglement characteristics, and investigates the influence of photon excitations on qua...This paper introduces two types of two-mode excited entangled coherent states （TMEECSs） ψ±（（α,m,n））, studies their entanglement characteristics, and investigates the influence of photon excitations on quantum entanglement. It shows that for the state （ψ＋ （α, m, m）} the two-mode photon excitations affect seriously entanglement character while the state [ ψ-（α, m, m）） is always a maximally entangled state, and shows how such states can be produced by using cavity quantum electrodynamics and quantum measurements. It finds that the entanglement amount of the TMEECSs is larger than that of the single-mode excited entangled coherent states with the same photon excitation number.展开更多
This paper introduces the generalized excited pair coherent state （GEPCS）. Using the entangled state 〈η〉 representation of Wigner operator, it obtains the Wigner function for the GEPCS. In the ρ-γ phase space, ...This paper introduces the generalized excited pair coherent state （GEPCS）. Using the entangled state 〈η〉 representation of Wigner operator, it obtains the Wigner function for the GEPCS. In the ρ-γ phase space, the variations of the Wigner function distributions with the parameters q, α, k and l are discussed. The tomogram of the GEPCS is calculated with the help of the Radon transform between the Wigner operator and the projection operator of the entangled state ｜η1, η2, τ1, τ2｜. The entangled states ｜η〉 and ｜η1, η2, τ1, τ2〉 provide two good representative space for studying the Wigner functions and tomograms of various two-mode correlated quantum states.展开更多
QUANTIZED radiation fields exhibiting nonclassical properties have been of great theoretical andexperimental interest in the last two decades. It is shown that various nonclassical states suchas squeezed state and Sch...QUANTIZED radiation fields exhibiting nonclassical properties have been of great theoretical andexperimental interest in the last two decades. It is shown that various nonclassical states suchas squeezed state and Schrodinger cat state can be generated out of coherent state in thenonlinear process of the interaction of atom and field although the radiation field in a展开更多
Recently, the quantum description of electromagnetic waves in conducting media has been performed. It has been demonstrated that in particular case, the Hamiltonian of the corresponding field can be expressed by Caldi...Recently, the quantum description of electromagnetic waves in conducting media has been performed. It has been demonstrated that in particular case, the Hamiltonian of the corresponding field can be expressed by Caldirola–Kanai Hamiltonian. In this paper, using the associated annihilation and creation operators of the above-mentioned quantized field, the time-and conductivity-dependent squeezed vacuum and one-photon squeezed states as well as their superpositions, and also the time-and conductivity-dependent excited even and odd coherent states are produced. Also,using a few well-known nonclassicality criteria, the time evolution of nonclassicality features of the above classes of obtained states, in addition to the influence of medium conductivity on them are demonstrated, numerically. It has been shown that the nonclassicality indicators may be adjusted by tuning the conductivity of media.展开更多
Light absorption and energy transfer were studied in a bionic system with donors and an acceptor.In the optimal case of uniform couplings,this seemingly complicated system was reduced to a three-level L-type system.Wi...Light absorption and energy transfer were studied in a bionic system with donors and an acceptor.In the optimal case of uniform couplings,this seemingly complicated system was reduced to a three-level L-type system.With this observation,we showed that the efficiency of energy transfer through a dark-state channel,which is free of the spontaneous decay of the donors,was dramatically improved.After the overall average transfer time was evaluated,it was revealed that the time required for transfer through this channel was not optimal.To find the optimal parameters for the present system,we defined a new quantity,output power,which characterizes the average mean output of the whole transfer process.We estimated the optimal parameters of the system to achieve the maximum output power.The splitting behaviour of the maximum power may be used to explain the phenomenon of photosynthetic systems primarily absorbing two colours of light.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10775048 and 10325523)the National Fundamental Research Program of China (Grant No 2007CB925204)the Funds from the Education Department of Hunan Province
文摘This paper introduces two types of two-mode excited entangled coherent states （TMEECSs） ψ±（（α,m,n））, studies their entanglement characteristics, and investigates the influence of photon excitations on quantum entanglement. It shows that for the state （ψ＋ （α, m, m）} the two-mode photon excitations affect seriously entanglement character while the state [ ψ-（α, m, m）） is always a maximally entangled state, and shows how such states can be produced by using cavity quantum electrodynamics and quantum measurements. It finds that the entanglement amount of the TMEECSs is larger than that of the single-mode excited entangled coherent states with the same photon excitation number.
基金supported by the National Natural Science Foundation of China (Grant No 10574060)the Natural Science Foundation of Shandong Province of China (Grant No Y2004A09)
文摘This paper introduces the generalized excited pair coherent state （GEPCS）. Using the entangled state 〈η〉 representation of Wigner operator, it obtains the Wigner function for the GEPCS. In the ρ-γ phase space, the variations of the Wigner function distributions with the parameters q, α, k and l are discussed. The tomogram of the GEPCS is calculated with the help of the Radon transform between the Wigner operator and the projection operator of the entangled state ｜η1, η2, τ1, τ2｜. The entangled states ｜η〉 and ｜η1, η2, τ1, τ2〉 provide two good representative space for studying the Wigner functions and tomograms of various two-mode correlated quantum states.
文摘QUANTIZED radiation fields exhibiting nonclassical properties have been of great theoretical andexperimental interest in the last two decades. It is shown that various nonclassical states suchas squeezed state and Schrodinger cat state can be generated out of coherent state in thenonlinear process of the interaction of atom and field although the radiation field in a
文摘Recently, the quantum description of electromagnetic waves in conducting media has been performed. It has been demonstrated that in particular case, the Hamiltonian of the corresponding field can be expressed by Caldirola–Kanai Hamiltonian. In this paper, using the associated annihilation and creation operators of the above-mentioned quantized field, the time-and conductivity-dependent squeezed vacuum and one-photon squeezed states as well as their superpositions, and also the time-and conductivity-dependent excited even and odd coherent states are produced. Also,using a few well-known nonclassicality criteria, the time evolution of nonclassicality features of the above classes of obtained states, in addition to the influence of medium conductivity on them are demonstrated, numerically. It has been shown that the nonclassicality indicators may be adjusted by tuning the conductivity of media.
基金This work is supported by the Natural Science Foundation of China through Grant nos.10935010 and 11074261.
文摘Light absorption and energy transfer were studied in a bionic system with donors and an acceptor.In the optimal case of uniform couplings,this seemingly complicated system was reduced to a three-level L-type system.With this observation,we showed that the efficiency of energy transfer through a dark-state channel,which is free of the spontaneous decay of the donors,was dramatically improved.After the overall average transfer time was evaluated,it was revealed that the time required for transfer through this channel was not optimal.To find the optimal parameters for the present system,we defined a new quantity,output power,which characterizes the average mean output of the whole transfer process.We estimated the optimal parameters of the system to achieve the maximum output power.The splitting behaviour of the maximum power may be used to explain the phenomenon of photosynthetic systems primarily absorbing two colours of light.
