A generalized type of spiral Bessel beam has been demonstrated by using a spatially displaced helical axicon （HA）. The topological charge of the spiraling Bessel beams is determined by the order of the input Laguerr...A generalized type of spiral Bessel beam has been demonstrated by using a spatially displaced helical axicon （HA）. The topological charge of the spiraling Bessel beams is determined by the order of the input Laguerre Gaussian （LG） beam and the topological charge of the HA. The obtained spiraling Bessel beams have an LG type of modulation along their propagation direction and exhibit annihilation-reconstruction properties. Theoretical analysis is presented, including that of the stability, propagation distance, topological charge, and spiraling dynamic characteristics. The mathematical and numerical results show that the propagation distance and helical revolution of the spiraling Bessel beams can be controlled through choosing appropriate radius of the HA.展开更多
We consider a model which consists of two coupled superconducting charge qubits by sharing a large Josephson junction.The time evolution of entanglement between two Josephson charge qubits is investigated by employing...We consider a model which consists of two coupled superconducting charge qubits by sharing a large Josephson junction.The time evolution of entanglement between two Josephson charge qubits is investigated by employing the concurrence.We examine the influence of the initial mean photon number,the relative phase and the amplitude of the two qubits on the time evolution of entanglement.The results show that the initial mean photon number,the relative phase and the amplitude of the two qubits play an important role in the evolution of entanglement.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2011CB301801)the National Natural Science Foundation of China(Grant Nos.10974039,11047153,10904027,61008039,and 11104049)+1 种基金the Doctoral Program of Higher Education of China(Grant No.20102302120009)the Fundamental Research Funds for the Central Universities of China(Grant No.2009038)
文摘A generalized type of spiral Bessel beam has been demonstrated by using a spatially displaced helical axicon （HA）. The topological charge of the spiraling Bessel beams is determined by the order of the input Laguerre Gaussian （LG） beam and the topological charge of the HA. The obtained spiraling Bessel beams have an LG type of modulation along their propagation direction and exhibit annihilation-reconstruction properties. Theoretical analysis is presented, including that of the stability, propagation distance, topological charge, and spiraling dynamic characteristics. The mathematical and numerical results show that the propagation distance and helical revolution of the spiraling Bessel beams can be controlled through choosing appropriate radius of the HA.
基金by the National Basic Research Program of China under Grant No 2011CB301801 and the National Natural Science Foundation of China under Grant No 10974039.
文摘We consider a model which consists of two coupled superconducting charge qubits by sharing a large Josephson junction.The time evolution of entanglement between two Josephson charge qubits is investigated by employing the concurrence.We examine the influence of the initial mean photon number,the relative phase and the amplitude of the two qubits on the time evolution of entanglement.The results show that the initial mean photon number,the relative phase and the amplitude of the two qubits play an important role in the evolution of entanglement.
