Signatures of strong correlation effects in RIXS on Cuprates

Recently, spin excitations in doped cuprates are measured using the resonant inelastic X-ray scattering (RIXS). The paramagnon dispersions show the large hardening effect in the electron-doped systems and seemingly doping-independence in the hole-doped systems, with the energy scales comparable to that of the antiferromagnetic magnons. This anomalous hardening effect was partially explained by using the strong coupling t-J model but with a three-site term(Nature communications 5, 3314 (2014)). However we show that hardening effect is a signature of strong coupling physics even without including this extra term. By considering the t-t'-t"-J model and using the Slave-Boson (SB) mean field theory, we obtain, via the spin-spin susceptibility, the spin excitations in qualitative agreement with the experiments. These anomalies is mainly due to the doping-dependent bandwidth. We further discuss the interplay between particle-hole-like and paramagnon-like excitations in the RIXS measurements.Comment: 7 pages, 6 figure

Bar-induced central star formation as revealed by integral field spectroscopy from CALIFA

We investigate the recent star formation history (SFH) in the inner region of 57 nearly face-on spiral galaxies selected from the Calar Alto Legacy Integral Field Area (CALIFA) survey. For each galaxy we use the integral field spectroscopy from CALIFA to obtain two-dimensional maps and radial profiles of three parameters that are sensitive indicators of the recent SFH: the 4000\AA\ break (D$_n$(4000)), and the equivalent width of H$\delta$ absorption (EW(H$\delta_A$)) and H$\alpha$ emission (EW(H$\alpha$)). We have also performed photometric decomposition of bulge/bar/disk components based on SDSS optical image. We identify a class of 17 "turnover" galaxies whose central region present significant drop in D$_n$(4000), and most of them correspondingly show a central upturn in EW(H$\delta_A$) and EW(H$\alpha$). This indicates that the central region of the turnover galaxies has experienced star formation in the past 1-2 Gyr, which makes the bulge younger and more star-forming than surrounding regions. We find almost all (15/17) the turnover galaxies are barred, while only half of the barred galaxies in our sample (15/32) are classified as a turnover galaxy. This finding provides strong evidence in support of the theoretical expectation that the bar may drive gas from the disc inward to trigger star formation in galaxy center, an important channel for the growth/rejuvenation of pseudobulges in disc galaxies.Comment: 19 pages, 10 figures, ApJ accepte

Capacity of a simultaneous quantum secure direct communication scheme between the central party and other M parties

We analyze the capacity of a simultaneous quantum secure direct communication scheme between the central party and other $M$ parties via $M+1$-particle GHZ states and swapping quantum entanglement. It is shown that the encoding scheme should be secret if other $M$ parties wants to transmit $M+1$ bit classical messages to the center party secretly. However when the encoding scheme is announced publicly, we prove that the capacity of the scheme in transmitting the secret messages is 2 bits, no matter how big $M$ is.Comment: 3 page

Where to Display What? Using AR to Improve Work Performance

Augmented reality (AR) is emerging as a next-generation interactive technology with the ability to display information in the immediate field of vision (i.e., near-eye display). This study investigates the interplay between information provision channels and information types on worker performance. A field experiment reveals that workers who follow instructions shown on AR glasses achieve higher work attentiveness and work performance than workers who receive this information on a mobile phone. Moreover, the effects of AR on work performance are moderated by information type. When the instructional information is highly dependent on the physical context, AR is more helpful in improving work performance. However, when the information is highly complex, the superiority of AR is weakened. This work contributes to the IS and HCI literature by revealing the value of AR in industrial organizations, and the boundary conditions for which AR affects worker performance

Action to Acquisition—Boost Students’ English Learning Motivation with Filmmaking Project

In Taiwan, English is more a major subject matter for student to “study” in school rather than a language for people to use in real life situations. Under the situation, students tend to have lower learning motivation when come to English classes, especially in higher academic settings, like universities. In order to boost students’ learning motivation as well as to encourage their productivity and creativity at the same time, a preliminary action research was conducted by two researchers collaboratively whereas one researcher is the instructor simultaneously. The major focus of the action research is concerning the application of “filmmaking” as a potentially effective tool to attract students into the classroom activities as well as the lesson content. For four semesters successively, a semester project has been assigned to 10 classes. By the end of each semester, reflections from students and the instructor were collected for refining purpose. From the students’ reflection and random interviews, an interesting comment appeared repeatedly: although the filmmaking project required them much effort and time, the results brought them the excessive fun and sense of accomplishment