Observation of backscattering-immune chiral electromagnetic modes without time reversal breaking

A strategy is proposed to realize robust transport in time reversal invariant photonic system. Using numerical simulation and microwave experiment, we demonstrate that a chiral guided mode in the channel of a three-dimensional dielectric woodpile photonic crystal is immune to the scattering of a square patch of metal or dielectric inserted to block the channel. The chirality based robust transport can be realized in nonmagnetic dielectric materials without any external field.Comment: 16 pages, 5 figure

Gapped Topological Kink States and Topological Corner States in Graphene

Based on the tight-binding model calculations and photonic experimental visualization on graphene, we report the domain-wall-induced gapped topological kink states and topological corner states. In graphene, domain walls with gapless topological kink states could be induced either by sublattice symmetry breaking or by lattice deformation. We find that the coexistence of these two mechanisms will induce domain walls with gapped topological kink states. Significantly, the intersection of these two types of domain wall gives rise to topological corner state localized at the crossing point. Through the manipulation of domain walls, we show graphene not only a versatile platform supporting multiple topological corner modes in a controlled manner, but also possessing promising applications such as fabricating topological quantum dots composed of gapped topological kink states and topological corner states.Comment: 5 pages, 5 figures, supplementary includ

Experimental observation of non-Hermitian higher-order skin interface states in topological electric circuits

The study of topological states has developed rapidly in electric circuits, which permits flexible fabrications of non-Hermitian systems by introducing non-Hermitian terms. Here, nonreciprocal coupling terms are realized by utilizing a voltage follower module in non-Hermitian topological electric circuits. We report the experimental realization of one- and two- dimensional non-Hermitian skin interface states in electric circuits, where interface states induced by non-Hermitian skin effects are localized at the interface of different domains carrying different winding numbers. Our electric circuit system provides a readily accessible platform to explore non-Hermitian-induced topological phases, and paves a new road for device applications

Global dynamic scaling relations of HI-rich ultra-diffuse galaxies

The baryonic Tully-Fisher relation (BTFR), which connects the baryonic mass of galaxies with their circular velocities, has been validated across a wide range of galaxies, from dwarf galaxies to massive galaxies. Recent studies have found that several ultra-diffuse galaxies (UDGs) deviate significantly from the BTFR, indicating a galaxy population with abnormal dynamical properties. However, such studies were still confined within a small sample size. In this study, we used the 100% complete Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) to investigate the BTFR of 88 HI-rich UDGs (HUDGs), which is the largest UDG sample with dynamical information. We found that the HUDGs form a continuous distribution in the BTFR diagram, with high-velocity galaxies consistent with normal dwarf galaxies at 1 $\sigma$ level, and low-velocity galaxies deviating from the BTFR, in line with that reported in the literature. We point out that the observed deviation may be subject to various selection effects or systemic biases. Nevertheless, we found that the significance of the deviation of HUDGs from the BTFR and TFR are different, i.e., they either deviate from the BTFR or from the TFR. Our result indicates that a high-gas fraction may play an important role in explaining the deviation of HUDGs from BTFR.Comment: 12 pages, 9 figures, 1 table, accepted for publication in ApJ

Experimental study and weighting analysis of factors influencing gas desorption

Gas is one of the necessary contributing factors for coal and gas outburst accidents, and the gas desorbed in coal is the energy carrier in the outburst process. The study of gas desorption laws is the premise and basis for gas content determination and gas accident prevention. To solve the problem of inaccurate gas content measurement due to the unclear characteristics of rapid gas desorption in 0–10 s, the gas desorption experimental device was improved, the influence factors of gas desorption were studied experimentally, and a comprehensive analysis method was proposed based on the gas desorption rate, gas desorption efficiency, initial gas desorption amount and total desorbed gas. The experiment analysed five factors that affected gas desorption, including the degree of metamorphism, type of failure, particle size, pressure and temperature. The results show that there is a monotonically decreasing power function relationship between the initial gas desorption rate and time and a monotonically increasing logarithmic function relationship between the gas desorption amount and time; the curve has a limit value. The gas desorption amount is large in 0–10 s and increases slowly afterwards. Among the factors affecting gas desorption, their importance decreases in the order of pressure > metamorphism > particle size > failure type > temperature. This study is of great practical value for the calculation of gas losses in gas content determination, and the resulting gas desorption laws are of great importance in guiding gas control work