Doublet bands in 126^{126}Cs in the triaxial rotor model coupled with two quasiparticles

The positive parity doublet bands based on the $\pi h_{11/2}\otimes\nu h_{11/2}$ configuration in $^{126}$Cs have been investigated in the two quasi-particles coupled with a triaxial rotor model. The energy spectra $E(I)$, energy staggering parameter $S(I)=[E(I)-E(I-1)]/2I$, $B(M1)$ and $B(E2)$ values, intraband $B(M1)/B(E2)$ ratios, $B(M1)_{\textrm{in}}/B(M1)_{\textrm{out}}$ ratios, and orientation of the angular momentum for the rotor as well as the valence proton and neutron are calculated. After including the pairing correlation, good agreement has been obtained between the calculated results and the data available, which supports the interpretation of this positive parity doublet bands as chiral bands.Comment: Phys.Rev.C (accepted

Joint effect of the western and eastern Pacific warm pools on ENSO cycle

International audienceThe zonal displacement of the western Pacific warm pool (WPWP) and the meridional displacement of the eastern Pacific warm pool (EPWP) and their responses to wind anomalies over the tropical Pacific were investigated. Joint effect of the WPWP and EPWP on ENSO was examined based on a joint effect index, which is a combination of the standardized anomaly time series of the eastern edge of the WPWP and the southern edge of the EPWP. Results show that both WPWP and EPWP are major providers of warm water in the eastern equatorial Pacific. The anomalous eastward extension of the WPWP and abnormal southward extension of the EPWP can supply a large amount of warm water into Nino3 region of the north equator, result in dramatic local SST increase, and trigger El Niño. To the contrary, as scope of the WPWP retreats westward and the EPWP retreats northward, a La Niña will outburst. One cannot separate apart the roles played by the WPWP and EPWP on ENSO, and the joint effect of both warm pools must be considered. A joint index of 1.6 means a new El Niño event is likely to happen

Temporal sparse feature auto-combination deep network for video action recognition

In order to deal with action recognition for large‐scale video data, we present a spatio‐temporal auto‐combination deep network, which is able to extract deep features from short video segments by making full use of temporal contextual correlation of corresponding pixels among successive video frames. Based on conventional sparse encoding, we further consider the representative features in adjacent nodes of the hidden layers according to activation states similarities. A sparse auto‐combination strategy is applied to multiple input maps in each convolution stage. An information constraint of the representative features of hidden layer nodes is imposed to handle the adaptive sparse encoding of the topology. As a result, the learned features can represent the spatio‐temporal transition relationships better and the number of hidden nodes can be restricted to a certain range. We conduct a series of experiments on two public data sets. The experimental results show that our approach is more effective and robust in video action recognition compared with traditional methods

Observation of Landau quantization and standing waves in HfSiS

Recently, HfSiS was found to be a new type of Dirac semimetal with a line of Dirac nodes in the band structure. Meanwhile, Rashba-split surface states are also pronounced in this compound. Here we report a systematic study of HfSiS by scanning tunneling microscopy/spectroscopy at low temperature and high magnetic field. The Rashba-split surface states are characterized by measuring Landau quantization and standing waves, which reveal a quasi-linear dispersive band structure. First-principles calculations based on density-functional theory are conducted and compared with the experimental results. Based on these investigations, the properties of the Rashba-split surface states and their interplay with defects and collective modes are discussed.Comment: 6 pages, 5 figure

Chiral bands for quasi-proton and quasi-neutron coupling with a triaxial rotor

A particle rotor model (PRM) with a quasi-proton and a quasi-neutron coupled with a triaxial rotor is developed and applied to study chiral doublet bands with configurations of a $h_{11/2}$ proton and a $h_{11/2}$ quasi-neutron. With pairing treated by the BCS approximation, the present quasi-particle PRM is aimed at simulating one proton and many neutron holes coupled with a triaxial rotor. After a detailed analysis of the angular momentum orientations, energy separation between the partner bands, and behavior of electromagnetic transitions, for the first time we find aplanar rotation or equivalently chiral geometry beyond the usual one proton and one neutron hole coupled with a triaxial rotor.Comment: 25 pages, 10 figures, accepted for publication in Physical Review

Summer Upwelling in the Northern Continental Shelf of the South China Sea

Summer upwelling system in the northern continental shelf of the South China Sea (NCSCS) is investigated with the Pathfinder, Advanced Very High Resolution Radiometer (AVHRR) Sea Surface Temperature (SST), and a three-dimensional, baroclinic, non-linear, numerical model forced by QuikSCAT winds. The AVHRR observation and modelling results have shown the upwelling is a regular phenomenon during summer in the NCSCS. Continental shelf upwelling characteristics are clearly found in the surface and subsurface water, such as low temperature, high salinity and high potential density. They respectively locate in the east of the Hainan Island, the east of the Leizhou Peninsula and the southeast of the Zhanjiang Bay (Qiongdong Upwelling), and the inshore areas from the Shantou Coast to the Nanri Islands of Fujian Coast (Yuedong Upwelling). The centra of the upwelling are mostly located in 111°10′E、19°45′N between the Qinglan Bay and the Qizhou Archipelagoes of eastern Hainan Island, 110°15′E、18°25′N near the Lingshui Bay, 116°45′E、22°50′N of the Shantou Coast and 118°E、23°40′N near the Taiwan Shoal. It is also found that the upwelling areas and centra from modelling results are in agreement with the AVHRR SST

A characterization of compact complex tori via automorphism groups

We show that a compact Kaehler manifold X is a complex torus if both the continuous part and discrete part of some automorphism group G of X are infinite groups, unless X is bimeromorphic to a non-trivial G-equivariant fibration. Some applications to dynamics are given.Comment: title changed, to appear in Math. An

Polaronic transport induced by competing interfacial magnetic order in a La0.7_{0.7}Ca0.3_{0.3}MnO3_{3}/BiFeO3_{3} heterostructure

Using ultrafast optical spectroscopy, we show that polaronic behavior associated with interfacial antiferromagnetic order is likely the origin of tunable magnetotransport upon switching the ferroelectric polarity in a La$_{0.7}$Ca$_{0.3}$MnO$_{3}$/BiFeO$_{3}$ (LCMO/BFO) heterostructure. This is revealed through the difference in dynamic spectral weight transfer between LCMO and LCMO/BFO at low temperatures, which indicates that transport in LCMO/BFO is polaronic in nature. This polaronic feature in LCMO/BFO decreases in relatively high magnetic fields due to the increased spin alignment, while no discernible change is found in the LCMO film at low temperatures. These results thus shed new light on the intrinsic mechanisms governing magnetoelectric coupling in this heterostructure, potentially offering a new route to enhancing multiferroic functionality