Kondo Phase in Twisted Bilayer Graphene -- A Unified Theory for Distinct Experiments

A number of interesting physical phenomena have been discovered in magic-angle twisted bilayer graphene (MATBG), such as superconductivity, correlated gapped and gapless phases, etc. The gapped phases are believed to be symmetry-breaking states described by mean-field theories, whereas gapless phases exhibit features beyond mean field. This work, combining poor man's scaling, numerical renormalization group, and dynamic mean-field theory, demonstrates that the gapless phases are the heavy Fermi liquid state with some symmetries broken and the others preserved. We adopt the recently proposed topological heavy fermion model for MATBG with effective local orbitals around AA-stacking regions and Dirac fermions surrounding them. At zero temperature and most non-integer fillings, the ground states are found to be heavy Fermi liquids and exhibit Kondo resonance peaks. The Kondo temperature $T_K$ is found at the order of 1meV. A higher temperature than $T_K$ will drive the system into a metallic LM phase where disordered LM's and a Fermi liquid coexist. At integer fillings $\pm1,\pm2$, $T_K$ is suppressed to zero or a value weaker than RKKY interaction, leading to Mott insulators or symmetry-breaking states. This theory offers a unified explanation for several experimental observations, such as zero-energy peaks and quantum-dot-like behaviors in STM, the Pomeranchuk effect, and the saw-tooth feature of inverse compressibility, etc. For future experimental verification, we predict that the Fermi surface in the gapless phase will shrink upon heating - as a characteristic of the heavy Fermi liquid. We also conjecture that the heavy Fermi liquid is the parent state of the observed unconventional superconductivity because the Kondo screening reduces the overwhelming Coulomb interaction (~60meV) to a rather small effective interaction (~1meV) comparable to possible weak attractive interactions.Comment: DMFT calculations for the THF model and discussions on possible symmetry-breaking states are adde

N 2,N 2,N 5,N 5-Tetra­kis(2-chloro­ethyl)-3,4-dimethyl­thio­phene-2,5-dicarboxamide

In the title compound, C16H22Cl4N2O2S, the two imide groups adopt a trans arrangement relative to the central thienyl ring, so the four terminal 2-chloro­ethyl arms adopt different orientations. In the crystal, mol­ecules are linked by weak C—H⋯Cl and C—H⋯O hydrogen bonds into a three-dimensional network

Anchor Retouching via Model Interaction for Robust Object Detection in Aerial Images

Object detection has made tremendous strides in computer vision. Small object detection with appearance degradation is a prominent challenge, especially for aerial observations. To collect sufficient positive/negative samples for heuristic training, most object detectors preset region anchors in order to calculate Intersection-over-Union (IoU) against the ground-truthed data. In this case, small objects are frequently abandoned or mislabeled. In this paper, we present an effective Dynamic Enhancement Anchor (DEA) network to construct a novel training sample generator. Different from the other state-of-the-art techniques, the proposed network leverages a sample discriminator to realize interactive sample screening between an anchor-based unit and an anchor-free unit to generate eligible samples. Besides, multi-task joint training with a conservative anchor-based inference scheme enhances the performance of the proposed model while reducing computational complexity. The proposed scheme supports both oriented and horizontal object detection tasks. Extensive experiments on two challenging aerial benchmarks (i.e., DOTA and HRSC2016) indicate that our method achieves state-of-the-art performance in accuracy with moderate inference speed and computational overhead for training. On DOTA, our DEA-Net which integrated with the baseline of RoI-Transformer surpasses the advanced method by 0.40% mean-Average-Precision (mAP) for oriented object detection with a weaker backbone network (ResNet-101 vs ResNet-152) and 3.08% mean-Average-Precision (mAP) for horizontal object detection with the same backbone. Besides, our DEA-Net which integrated with the baseline of ReDet achieves the state-of-the-art performance by 80.37%. On HRSC2016, it surpasses the previous best model by 1.1% using only 3 horizontal anchors

Flexible surface acoustic wave resonators built on disposable plastic film for electronics and lab-on-a-chip applications

Flexible electronics are a very promising technology for various applications. Several types of flexible devices have been developed, but there has been limited research on flexible electromechanical systems (MEMS). Surface acoustic wave (SAW) devices are not only an essential electronic device, but also are the building blocks for sensors and MEMS. Here we report a method of making flexible SAW devices using ZnO nanocrystals deposited on a cheap and bendable plastic film. The flexible SAW devices exhibit two wave modes - the Rayleigh and Lamb waves with resonant frequencies of 198.1 MHz and 447.0 MHz respectively, and signal amplitudes of 18 dB. The flexible devices have a high temperature coefficient of frequency, and are thus useful as sensitive temperature sensors. Moreover, strong acoustic streaming with a velocity of 3.4 cm/s and particle concentration using the SAW have been achieved, demonstrating the great potential for applications in electronics and MEMS

Effects of tourmaline on growth of three kinds of microorganisms

Tourmaline is a kind of widespread minerals and has been used in many fields of society. Owing to the special electric properties, tourmaline can destroy the hydrogen bond between water molecules. The growth of microorganism may be affected with addition of tourmaline; therefore the effects of tourmaline on three different kinds of microorganisms were studied using microcalorimetric method. The kinetic parameters of growth process were obtained through the thermogenic curves. The results show that high concentration tourmaline inhibited the growth of prokaryotic cells (the growth rate constant of Escherichia coli and Staphylococcus aureus decreased 68.77 and 35.25% at tourmaline concentration of 160 g/L), while promoted eukaryotic cell (the growth rate constant of Candida albicans increased 40.73% at tourmaline concentration of 160 g/L). However, the low concentration tourmaline had complex effects on growth of the studied microorganisms.Key words: Microcalorimetric, water cluster, growth rate, inhibitory ratio

Real-space hole-doping titration and manipulation of correlated charge density wave state in 1T-TaS2

The complex correlated charge density wave (CDW) phases of 1T-TaS2 have attracted great attention due to their emergent quantum states, such as intricate CDW phase, Mott-Hubbard state, superconductivity and quantum spin liquid. The delicate interplay among the complex intra-/inter-layer electron-electron and electron-lattice interactions is the fundamental prerequisite of these exotic quantum states. Here, we report a real-space titration-like investigation of correlated CDW state in 1T-TaS2 upon hole-doping via low-temperature scanning tunneling microscopy (LT-STM). The gradual increased hole-doping results in the sequential emergence of electron voids, phase domains, stacking disordering and mixed phase/chiral domains attributed to the reduced electron correlations. The achiral intermediate ring-like clusters and nematic CDW states emerge at the intralayer chiral domain wall and interlayer heterochiral stacking regions via the chiral-overlapping configurations. The local reversible CDW manipulation is further realized by the non-equilibrium transient charge-injections of STM field-emission spectra. Our results provide an in-depth insight of this intricate correlated CDW state, and pave a way to realize exotic quantum states via the accurate tuning of interior interactions in correlated materials

Characterization of the soybean KRP gene family reveals a key role for GmKRP2a in root development

Kip-related proteins (KRPs), as inhibitory proteins of cyclin-dependent kinases, are involved in the growth and development of plants by regulating the activity of the CYC-CDK complex to control cell cycle progression. The KRP gene family has been identified in several plants, and several KRP proteins from Arabidopsis thaliana have been functionally characterized. However, there is little research on KRP genes in soybean, which is an economically important crop. In this study, we identified nine GmKRP genes in the Glycine max genome using HMM modeling and BLASTP searches. Protein subcellular localization and conserved motif analysis showed soybean KRP proteins located in the nucleus, and the C-terminal protein sequence was highly conserved. By investigating the expression patterns in various tissues, we found that all GmKRPs exhibited transcript abundance, while several showed tissue-specific expression patterns. By analyzing the promoter region, we found that light, low temperature, an anaerobic environment, and hormones-related cis-elements were abundant. In addition, we performed a co-expression analysis of the GmKRP gene family, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) set enrichment analysis. The co-expressing genes were mainly involved in RNA synthesis and modification and energy metabolism. Furthermore, the GmKRP2a gene, a member of the soybean KRP family, was cloned for further functional analysis. GmKRP2a is located in the nucleus and participates in root development by regulating cell cycle progression. RNA-seq results indicated that GmKRP2a is involved in cell cycle regulation through ribosome regulation, cell expansion, hormone response, stress response, and plant pathogen response pathways. To our knowledge, this is the first study to identify and characterize the KRP gene family in soybean

Simulation study of BESIII with stitched CMOS pixel detector using ACTS

Reconstruction of tracks of charged particles with high precision is very crucial for HEP experiments to achieve their physics goals. As the tracking detector of BESIII experiment, the BESIII drift chamber has suffered from aging effects resulting in degraded tracking performance after operation for about 15 years. To preserve and enhance the tracking performance of BESIII, one of the proposals is to add one layer of thin CMOS pixel sensor in cylindrical shape based on the state-of-the-art stitching technology, between the beam pipe and the drift chamber. The improvement of tracking performance of BESIII with such an additional pixel detector compared to that with only the existing drift chamber is studied using the modern common tracking software ACTS, which provides a set of detector-agnostic and highly performant tracking algorithms that have demonstrated promising performance for a few high energy physics and nuclear physics experiments