Mode entanglement of electrons in the one-dimensional Frenkel-Kontorova model

We study the mode entanglement in the one-dimensional Frenkel-Kontorova model, and found that behaviors of quantum entanglement are distinct before and after the transition by breaking of analyticity. We show that the more extended the electron is, the more entangled the corresponding state. Finally, a quantitative relation is given between the average square of the concurrence quantifying the degree of entanglement and the participation ratio characterizing the degree of localization.Comment: 4 pages, 4 figures. V

An Empirical Study of the Effect of Investor Sentiment on Returns of Different Industries

Studies on investor sentiment are mostly focused on the stock market, but little attention has been paid to the effect of investor sentiment on the return of a specific industry. This paper constructs a proxy variable to examine the relationship between investor sentiment and the return of a specific industry, using the Principle Component Analysis, and finds that investor sentiment is positively correlated with the industry return of the current period and negatively correlated with that of one lag period; we classify investor sentiment as optimistic state and pessimistic state and find that optimistic investor sentiment has a positive effect on stock returns of most industries, while pessimistic investor sentiment has no effect on them; this paper further builds a two-state Markov regime switching model and finds that sentiment has different effect on different industries returns on different states of market

POLITICAL CONNECTIONS AND STOCK CRASH RISK-EMPIRICAL EVIDENCE FROM A-SHARE COMPANIES IN CHIN

Based on the sample data of 2010-2014 A-share companies in China, This thesis empirically tested the influence of political connections on stock price crash risk in the future. The results showed that both of political connections and political connections strength were remarkable negative correlation with the listed company's share price crash risk in the future. Research conclusion of this thesis has an important theoretical and practical significance both for overall understanding the economic consequences of political connections and how to guard against crash risk

RESEARCH ON INVESTMENT EFFICIENCY AND ITS INFLUENCING FACTORS OF IRON AND STEEL LISTING COMPANY

Iron and steel industry is one of the most serious duplicate construction industries, this paper reveals the micro basis of the repeated construction of the steel industry from the perspective of investment efficiency of iron and steel enterprises. This paper, based on the data of Chinese listed iron and steel company in 2010-2014, empirically tests its investment efficiency and influencing factors. The results show that over investment is consistent with inadequate investment in Chinese listed iron and steel company, and the overall performance is excessive investment. Among the influencing factors, investment opportunities, debt structure, government intervention, enterprise scale is positively related to over investment, and negatively related to the asset liability rati

Ground-state properties of the two-site Hubbard-Holstein model: an exact solution

We revisit the two-site Hubbard-Holstein model by using extended phonon coherent states. The nontrivial singlet bipolaron is studied exactly in the whole coupling regime. The ground-state (GS) energy and the double occupancy probability are calculated. The linear entropy is exploited successfully to quantify bipartite entanglement between electrons and their environment phonons, displaying a maximum entanglement of the singlet-bipolaron in strong coupling regime. A dramatic drop in the crossover regime is observed in the GS fidelity and its susceptibility. The bipolaron properties is also characterized classically by correlation functions. It is found that the crossover from a two-site to single-site bipolaron is more abrupt and shifts to a larger electron-phonon coupling strength as electron-electron Coulomb repulsion increases.Comment: 6 pages, 6 figure

Preparation and Photocatalytic Activity of Magnetic Fe 3

A simple sol-gel method was used to prepare magnetic Fe3O4/SiO2/TiO2 composites with core-shell structure. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) have been applied to investigate the structure and morphology of the resultant composites. The obtained composites showed excellent magnetism and higher photodegradation ability than pure TiO2. The photocatalytic mechanism was also discussed. The magnetic composites should be extended to various potential applications, such as photodegradation, catalysis, separation, and purification processes

PP-YOLOE-R: An Efficient Anchor-Free Rotated Object Detector

Arbitrary-oriented object detection is a fundamental task in visual scenes involving aerial images and scene text. In this report, we present PP-YOLOE-R, an efficient anchor-free rotated object detector based on PP-YOLOE. We introduce a bag of useful tricks in PP-YOLOE-R to improve detection precision with marginal extra parameters and computational cost. As a result, PP-YOLOE-R-l and PP-YOLOE-R-x achieve 78.14 and 78.28 mAP respectively on DOTA 1.0 dataset with single-scale training and testing, which outperform almost all other rotated object detectors. With multi-scale training and testing, PP-YOLOE-R-l and PP-YOLOE-R-x further improve the detection precision to 80.02 and 80.73 mAP. In this case, PP-YOLOE-R-x surpasses all anchor-free methods and demonstrates competitive performance to state-of-the-art anchor-based two-stage models. Further, PP-YOLOE-R is deployment friendly and PP-YOLOE-R-s/m/l/x can reach 69.8/55.1/48.3/37.1 FPS respectively on RTX 2080 Ti with TensorRT and FP16-precision. Source code and pre-trained models are available at https://github.com/PaddlePaddle/PaddleDetection, which is powered by https://github.com/PaddlePaddle/Paddle.Comment: 6 pages, 2 figures, 3 table