Beyond the Lamb-Dicke limit, this paper investigates the squeezing properties of the trapped ion in the travelling- wave laser. It shows that the squeezing properties of the trapped ion in the travelling-wave laser ar...Beyond the Lamb-Dicke limit, this paper investigates the squeezing properties of the trapped ion in the travelling- wave laser. It shows that the squeezing properties of the trapped ion in the travelling-wave laser are strongly affected by the sideband number k, the Lamb-Dicke parameter η and the initial average phonon number.展开更多
In this study, our goal is to obtain the entanglement dynamics of trapped three-level ion interaction two laser beams in beyond Lamb-Dicke parameters. Three values of LDP, <span style="white-space:nowrap;"...In this study, our goal is to obtain the entanglement dynamics of trapped three-level ion interaction two laser beams in beyond Lamb-Dicke parameters. Three values of LDP, <span style="white-space:nowrap;"><em>η</em>=0.09, <span style="white-space:nowrap;"><em>η</em>=0.2 </span></span>and <span style="white-space:nowrap;"><em>η</em>=0.3 </span>are given. We used the concurrence and the negativity to measure the amount of quantum entanglement created in the system. The interacting trapped ion led to the formation of phonons as a result of the coupling. In two quantum systems (ion-phonons), analytical formulas describing both these measurements are constructed. These formulas and probability coefficients include first order terms of final state vector. We report that long survival time of entanglement can be provided with two quantum measures. Negativity and concurrence maximum values are obtained N = 0.553 and for LDP = 0.3. As a similar, the other two values of LDP are determined and taken into account throughout this paper. For a more detailed understanding of entanglement measurement results, “contour plot” was preferred in Mathematica 8.展开更多
In the system with two two-level ions confined in a linear trap, this paper presents a simple scheme to realize the quantum phase gate （QPG） and the swap gate beyond the Lamb Dicke （LD） limit. These two-qubit quan...In the system with two two-level ions confined in a linear trap, this paper presents a simple scheme to realize the quantum phase gate （QPG） and the swap gate beyond the Lamb Dicke （LD） limit. These two-qubit quantum logic gates only involve the internal states of two trapped ions. The scheme does not use the vibrational mode as the data bus and only requires a single resonant interaction of the ions with the lasers. Neither the LD approximation nor the auxiliary atomic level is needed in the proposed scheme. Thus the scheme is simple and the interaction time is very short, which is important in view of decoherence. The experimental feasibility for achieving this scheme is also discussed.展开更多
The interaction of a single three-level trapped ion with two laser beams has been studied theoretically. With application of two successive unitary transformations, an analytical solution to this quantum system has be...The interaction of a single three-level trapped ion with two laser beams has been studied theoretically. With application of two successive unitary transformations, an analytical solution to this quantum system has been obtained.展开更多
The fidelity of the generated Schrodinger Cat state （SCS） of a single trapped ion in the Lamb-Dicke approximation is discussed. The results show that the fidelity significantly decreases with the values of Lamb-Dick...The fidelity of the generated Schrodinger Cat state （SCS） of a single trapped ion in the Lamb-Dicke approximation is discussed. The results show that the fidelity significantly decreases with the values of Lamb-Dicke parameter η and coherent state amplitude α increasing. For η= 0.20 and α = 3, the typical values of experimental parameters, the fidelity is rather low （3070）. A scheme for generating the SCS is proposed without making the Lamb-Dike approximation in laser-ion interaction, and the fidelity of the generated SCS is about 99% for the typical values of experimental Lamb- Dicke parameters.展开更多
The interaction of a single two-level two-mode trapped ion with a laser beam has been studied theoretically. With application of a unitary transformation, an analytical solution to this quantum system has been obtaine...The interaction of a single two-level two-mode trapped ion with a laser beam has been studied theoretically. With application of a unitary transformation, an analytical solution to this quantum system has been obtained without performing the Lamb-Dicke approximation. In this system the entangled displacement Fock state is produced.展开更多
Trapping ions outside the Lamb-Dicke limit have been proven to be useful for the laser-cooling and quantum computing.Under the supposition of the Rabi frequency much smaller than the Lamb Dicke parameter,we can use a ...Trapping ions outside the Lamb-Dicke limit have been proven to be useful for the laser-cooling and quantum computing.Under the supposition of the Rabi frequency much smaller than the Lamb Dicke parameter,we can use a simple method to analytically solve the system with a single cold ion trapped and radiated beyond the Lamb Dickc limit,in the absence of the rotating-wave approximation (RWA).Discussion has been made for the limitation of our approach and the comparison of our results with the solutions under the RWA.展开更多
By applying the nonlinear interaction between internal and external degrees of a trapped ion with theassistance of two pairs or three pairs of laser beams that are perpendicular to each other, the realization of quant...By applying the nonlinear interaction between internal and external degrees of a trapped ion with theassistance of two pairs or three pairs of laser beams that are perpendicular to each other, the realization of quantumlogic operation without the limitation on the Lamb-Dicke parameter can be achieved when the lasers are tuned to thecarrier.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10374025）.
文摘Beyond the Lamb-Dicke limit, this paper investigates the squeezing properties of the trapped ion in the travelling- wave laser. It shows that the squeezing properties of the trapped ion in the travelling-wave laser are strongly affected by the sideband number k, the Lamb-Dicke parameter η and the initial average phonon number.
文摘In this study, our goal is to obtain the entanglement dynamics of trapped three-level ion interaction two laser beams in beyond Lamb-Dicke parameters. Three values of LDP, <span style="white-space:nowrap;"><em>η</em>=0.09, <span style="white-space:nowrap;"><em>η</em>=0.2 </span></span>and <span style="white-space:nowrap;"><em>η</em>=0.3 </span>are given. We used the concurrence and the negativity to measure the amount of quantum entanglement created in the system. The interacting trapped ion led to the formation of phonons as a result of the coupling. In two quantum systems (ion-phonons), analytical formulas describing both these measurements are constructed. These formulas and probability coefficients include first order terms of final state vector. We report that long survival time of entanglement can be provided with two quantum measures. Negativity and concurrence maximum values are obtained N = 0.553 and for LDP = 0.3. As a similar, the other two values of LDP are determined and taken into account throughout this paper. For a more detailed understanding of entanglement measurement results, “contour plot” was preferred in Mathematica 8.
基金Project supported by the Important Program of Hunan Provincial Education Department (Grant No 06A038)Department of Education of Hunan Province (Grant No 06C080)+1 种基金Natural Science Foundation of Hunan Province, China (Grant No 07JJ3013)Postdoctoral Fund of China (Grant No 20070420825)
文摘In the system with two two-level ions confined in a linear trap, this paper presents a simple scheme to realize the quantum phase gate （QPG） and the swap gate beyond the Lamb Dicke （LD） limit. These two-qubit quantum logic gates only involve the internal states of two trapped ions. The scheme does not use the vibrational mode as the data bus and only requires a single resonant interaction of the ions with the lasers. Neither the LD approximation nor the auxiliary atomic level is needed in the proposed scheme. Thus the scheme is simple and the interaction time is very short, which is important in view of decoherence. The experimental feasibility for achieving this scheme is also discussed.
基金The project supported by the Natural Science Foundation of Education Committee of Anhui Province of China under Grant No. 2004kj186
文摘The interaction of a single three-level trapped ion with two laser beams has been studied theoretically. With application of two successive unitary transformations, an analytical solution to this quantum system has been obtained.
文摘The fidelity of the generated Schrodinger Cat state （SCS） of a single trapped ion in the Lamb-Dicke approximation is discussed. The results show that the fidelity significantly decreases with the values of Lamb-Dicke parameter η and coherent state amplitude α increasing. For η= 0.20 and α = 3, the typical values of experimental parameters, the fidelity is rather low （3070）. A scheme for generating the SCS is proposed without making the Lamb-Dike approximation in laser-ion interaction, and the fidelity of the generated SCS is about 99% for the typical values of experimental Lamb- Dicke parameters.
基金The project supported by the Natural Science Foundation of the Education Committee of Anhui Province of China under Grant No.2004kj186
文摘The interaction of a single two-level two-mode trapped ion with a laser beam has been studied theoretically. With application of a unitary transformation, an analytical solution to this quantum system has been obtained without performing the Lamb-Dicke approximation. In this system the entangled displacement Fock state is produced.
文摘Trapping ions outside the Lamb-Dicke limit have been proven to be useful for the laser-cooling and quantum computing.Under the supposition of the Rabi frequency much smaller than the Lamb Dicke parameter,we can use a simple method to analytically solve the system with a single cold ion trapped and radiated beyond the Lamb Dickc limit,in the absence of the rotating-wave approximation (RWA).Discussion has been made for the limitation of our approach and the comparison of our results with the solutions under the RWA.
文摘By applying the nonlinear interaction between internal and external degrees of a trapped ion with theassistance of two pairs or three pairs of laser beams that are perpendicular to each other, the realization of quantumlogic operation without the limitation on the Lamb-Dicke parameter can be achieved when the lasers are tuned to thecarrier.
