338 research outputs found
Anderson transition and mobility edges on hyperbolic lattices
Hyperbolic lattices, formed by tessellating the hyperbolic plane with regular
polygons, exhibit a diverse range of exotic physical phenomena beyond
conventional Euclidean lattices. Here, we investigate the impact of disorder on
hyperbolic lattices and reveal that the Anderson localization occurs at strong
disorder strength, accompanied by the presence of mobility edges. Taking the
hyperbolic and lattices as examples, we
employ finite-size scaling of both spectral statistics and the inverse
participation ratio to pinpoint the transition point and critical exponents.
Our findings indicate that the transition points tend to increase with larger
values of or curvature. In the limiting case of , we
further determine its Anderson transition using the cavity method, drawing
parallels with the random regular graph. Our work lays the cornerstone for a
comprehensive understanding of Anderson transition and mobility edges in
non-Euclidean lattices.Comment: 7+6 pages, 5+3 figure
Enhanced Short Text Modeling: Leveraging Large Language Models for Topic Refinement
Crafting effective topic models for brief texts, like tweets and news
headlines, is essential for capturing the swift shifts in social dynamics.
Traditional topic models, however, often fall short in accurately representing
the semantic intricacies of short texts due to their brevity and lack of
contextual data. In our study, we harness the advanced capabilities of Large
Language Models (LLMs) to introduce a novel approach termed "Topic Refinement".
This approach does not directly involve itself in the initial modeling of
topics but focuses on improving topics after they have been mined. By employing
prompt engineering, we direct LLMs to eliminate off-topic words within a given
topic, ensuring that only contextually relevant words are preserved or
substituted with ones that fit better semantically. This method emulates
human-like scrutiny and improvement of topics, thereby elevating the semantic
quality of the topics generated by various models. Our comprehensive evaluation
across three unique datasets has shown that our topic refinement approach
significantly enhances the semantic coherence of topics.Comment: 6 pages, 4 figure
Novel approach to investigate decays via
To avoid the impact from the background events directly from
annihilations or decays, we propose a novel approach to investigate
decays, in particular for its rare or forbidden decays, by using
produced in decays at the
charm factories. Based on the MC studies of a few typical decays,
, , , as well as
, the sensitivities could be obviously improved by taking
advantage of the extra constraint of . Using one trillion
events accumulated at the Super -Charm facility, the precision on the
investigation of decays could be improved significantly and the
observation of the rare decay is even accessable.Comment: 7 pages, 6 figure
Determining the macroinvertebrate community indicators and relevant environmental predictors of the Hun-Tai River Basin (Northeast China): A study based on community patterning
[EN] It is essential to understand the patterning of biota and environmental influencing factors for proper rehabilitation and management at the river basin scale. The Hun-Tai River Basin was extensively sampled four times for macroinvertebrate community and environmental variables during one year. Self-Organizing Maps (SOMs) were used to reveal the aggregation patterns of the 355 samples. Three community types (i.e., clusters) were found (at the family level) based on the community composition, which showed a clearly gradient by combining them with the representative environmental variables: minimally impacted source area, intermediately anthropogenic impacted sites, and highly anthropogenic impacted downstream area, respectively. This gradient was corroborated by the decreasing trends in density and diversity of macroinvertebrates. Distance from source, total phosphorus and water temperature were identified as the most important variables that distinguished the delineated communities. In addition, the sampling season, substrate type, pH and the percentage of grassland were also identified as relevant variables. These results demonstrated that macroinvertebrates communities are structured in a hierarchical manner where geographic and water quality prevail over temporal (season) and habitat (substrate type) features at the basin scale. In addition, it implied that the local-scale environment variables affected macroinvertebrates under the longitudinal gradient of the geographical and anthropogenic pressure. More than one family was identified as the indicator for each type of community. Abundance contributed significantly for distinguishing the indicators, while Baetidae with higher density indicated minimally and intermediately impacted area and lower density indicated highly impacted area. Therefore, we suggested the use of abundance data in community patterning and classification, especially in the identification of the indicator taxa. (C) 2018 Elsevier B.V. All rights reserved.This work was supported by the National Natural Science Foundation of China (51779275, 41501204, 51479219) and the IWHR Research & Development Support Program (WE0145B532017).Zhang, M.; Muñoz Mas, R.; Martinez-Capel, F.; Qu, X.; Zhang, H.; Peng, W.; Liu, X. (2018). Determining the macroinvertebrate community indicators and relevant environmental predictors of the Hun-Tai River Basin (Northeast China): A study based on community patterning. The Science of The Total Environment. 634:749-759. https://doi.org/10.1016/j.scitotenv.2018.04.021S74975963
Design and optimization of dispersion-flattened microarray-core fiber with ultralow loss for terahertz transmission
The paper establishes a late-model of microarray-core based polymer optical fiber with flattened dispersion and ultra-low losses. Its transmission properties are calculated by virtue of the beam propagation approach. From the simulation results, it finds that the modelled fiber has a near-zero dispersion property of 0.29 ± 0.16 ps/THz/cm in a frequency area of 1.05 THz to 1.78 THz, a high birefringence of 1.6 × 10-3, an ultra-low confinement loss of 3.78 × 10-10 dB/m, an effective mode field zone of 4.6 × 105 μm2, and a nonlinear coefficient of 1.2 km-1·W−1. With these good properties, the modelled fiber could be applied for ethanol detection and polarization maintaining THz applications
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