We propose a scheme to create an effective magnetic field, which can be perceived by cold neutral atoms in a two-dimensional optical lattice, with a laser field with a space-dependent phase and a conventional laser fi...We propose a scheme to create an effective magnetic field, which can be perceived by cold neutral atoms in a two-dimensional optical lattice, with a laser field with a space-dependent phase and a conventional laser field acting on A-type three-level atoms. When the dimensionless parameter a, being the ratio of flux through a lattice cell to one flux quantum, is rational, the energy spectrum shows a fractal band structure, which is so-called Hofstadter＇s butterfly.展开更多
We study the magnetic effect of the checkerboard superconducting wire network. Based on the de Gennes- Alexader theory, we obtain difference equations for superconducting order parameter in the wire network. Through s...We study the magnetic effect of the checkerboard superconducting wire network. Based on the de Gennes- Alexader theory, we obtain difference equations for superconducting order parameter in the wire network. Through solving these difference equations, we obtain the eigenvalues, linked to the coherence length, as a function of magnetic field. The diagram of eigenvalues shows a fractal structure, being so-called Hofstadter＇s butterfly. We also calculate and discuss the dependence of the transition temperature of the checkerboard superconducting wire network on the applied magnetic field, which is related to up-edge of the Hofstadter＇s butterfly spectrum.展开更多
Japanese butterfly ray Gymnura japonica from twinspot butterfly ray G. bimaculata based on a pair of white spots behind eyes or not, which was not reliable. To clarify the taxonomic status of G. japonica and G. bimacu...Japanese butterfly ray Gymnura japonica from twinspot butterfly ray G. bimaculata based on a pair of white spots behind eyes or not, which was not reliable. To clarify the taxonomic status of G. japonica and G. bimaculata, the nucleotide variation between the two butterfly rays was examined using mitochondrial DNA sequence comparisons. Approximately 585 bp of 16S ribosomal RNA （rRNA） and 1,128 bp cytochrome b （cyt b） genes were sequenced from representatives of two butterfly rays species in East China Sea. The results showed that there were the same sequences of 16S rRNA gene between two butterfly rays; six sites were variable among two butterfly rays of cyt b genes, the proportion of polymorphie loci was 0.53%, and two haplotypes were defined which genetic distance was 0.5%. Combined with the morphological character and the analysis of mtDNA sequence indicated that twinspot butterfly ray G. bimaculata was a synonym of Japanese butterfly ray G. japonica.展开更多
基金supported by the Teaching and Research Foundation for the Outstanding Young Faculty of Southeast University and National Natural Science Foundation of China under Grant No.10571091
文摘We propose a scheme to create an effective magnetic field, which can be perceived by cold neutral atoms in a two-dimensional optical lattice, with a laser field with a space-dependent phase and a conventional laser field acting on A-type three-level atoms. When the dimensionless parameter a, being the ratio of flux through a lattice cell to one flux quantum, is rational, the energy spectrum shows a fractal band structure, which is so-called Hofstadter＇s butterfly.
基金Supported by the Teaching and Research Foundation for the Outstanding Young Faculty of Southeast University
文摘We study the magnetic effect of the checkerboard superconducting wire network. Based on the de Gennes- Alexader theory, we obtain difference equations for superconducting order parameter in the wire network. Through solving these difference equations, we obtain the eigenvalues, linked to the coherence length, as a function of magnetic field. The diagram of eigenvalues shows a fractal structure, being so-called Hofstadter＇s butterfly. We also calculate and discuss the dependence of the transition temperature of the checkerboard superconducting wire network on the applied magnetic field, which is related to up-edge of the Hofstadter＇s butterfly spectrum.
文摘Japanese butterfly ray Gymnura japonica from twinspot butterfly ray G. bimaculata based on a pair of white spots behind eyes or not, which was not reliable. To clarify the taxonomic status of G. japonica and G. bimaculata, the nucleotide variation between the two butterfly rays was examined using mitochondrial DNA sequence comparisons. Approximately 585 bp of 16S ribosomal RNA （rRNA） and 1,128 bp cytochrome b （cyt b） genes were sequenced from representatives of two butterfly rays species in East China Sea. The results showed that there were the same sequences of 16S rRNA gene between two butterfly rays; six sites were variable among two butterfly rays of cyt b genes, the proportion of polymorphie loci was 0.53%, and two haplotypes were defined which genetic distance was 0.5%. Combined with the morphological character and the analysis of mtDNA sequence indicated that twinspot butterfly ray G. bimaculata was a synonym of Japanese butterfly ray G. japonica.
