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479 results on '"Wang, Yanqi"'

1. A holographic model of magnetohydrodynamics with fortuitous SO(3) symmetry

Author

Wang, Yanqi, Hu, Peng-Ju, and Pang, Yi

Subjects
High Energy Physics - Theory, General Relativity and Quantum Cosmology
Abstract

We study magnetohydrodynamics using holography. The gravity model is closely related to the STU supergravity in five dimensions and admits an analytical black brane solution carrying the conserved charge dual to the magnetic 1-form symmetry of the magnetohydrodynamic system. The black brane solution features a fortuitous SO(3) symmetry, providing a new symmetry principle for describing the magnetohydrodynamics. Since the bulk theory contains multiple 2-form gauge fields, the resistivity becomes matrix-valued. We find that the antisymmetric part of the resistivity matrix exhibits novel features depending on the UV cut-off of the theory. We also compute the shear and bulk viscosities and find that the bulk viscosity is proportional to the shear viscosity. Remarkably, the proportionality constant is exactly what is required for conformality, despite the zeroth-order energy-momentum tensor not being trace-free., Comment: 24 pages, 5 figures

Published
2024

3. The dynamical second-order transport coefficients of smeared Dp-brane

Author

Wu, Chao, Wang, Yanqi, and Wang, Yi-An

Subjects
High Energy Physics - Theory
Abstract

The smeared Dp-brane is constructed by having the black Dp-brane uniformly smeared over several transverse directions. After integrating the spherical directions and the smeared directions, the smeared Dp-brane turns out to be a Chamblin-Reall model with one background scalar field. Within the framework of the fluid/gravity correspondence, we not only prove the equivalence between the smeared Dp-brane and the compactified Dp-brane by explicitly calculating the 7 dynamical second-order transport coefficients of their dual relativistic fluids, but also revisit the Correlated Stability Conjecture for the smeared Dp-brane via the fluid/gravity correspondence., Comment: 25pages, 2 tables

Published
2023

5. Effects of Vegetation Restoration Patterns on Soil Water-stable Aggregates Composition and Their Stability in the Water Level Fluctuation Zone of the Heilongtan Reservoir

Author

BAI Qinfei, WANG Yanqi, BAO Yuhai, HE Xiubin, LUO Peng, and WEI Jie

Subjects
hilly region of central sichuan basin, water level fluctuation zone, vegetation restoration, soil water-stable aggregates, aggregate stability, Environmental sciences, GE1-350, Agriculture
Abstract

[Objective] This study aimed at elucidating the effects of different vegetation restoration modes on soil water-stable aggregates and stability in the water level fluctuation zone (WLFZ). [Methods] The characteristics of soil water-stable aggregates and their stability indexes were determined and analyzed by the wet sieve method on the soil under artificially and naturally restored vegetation in the WLFZ in the hilly region of central Sichuan Basin. [Results] The content of >0.25 mm water-stable macroaggregates in WLFZ soils was 4.21% lower compared to unflooded area. The soil water stability macroaggregates content decreased by 12.27% under naturally restored vegetation and increased by 3.84% under artificially restored vegetation compared to unflooded area; With the rise of water elevations, the soil water stability macroaggregates content showed an increasing trend, the microaggregates content showed an overall decreasing trend, and the soil aggregate stability gradually increased with the rise of water elevations; The soil water-stable aggregates composition differed significantly (p

Published
2024
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11. Compactified AdS black holes, Chamblin-Reall background, and their dual non-conformal relativistic fluids

Author

Wu, Chao and Wang, Yanqi

Subjects
High Energy Physics - Theory
Abstract

The Chamblin-Reall background is a static solution of Einstein gravity coupled with a background scalar field and a dynamical domain wall, with the potential of the scalar field being of Liouville type. It can be got by dimensionally reducing a higher dimensional background with a constant potential. Compactified AdS black holes are black hole backgrounds constructed by wrapping one or more spatial directions of a higher dimensional AdS black hole on a torus and then integrating them out. The compactified AdS black hole background is asymptotically flat, non-conformal, and of Chamblin-Reall type. In this work, we derive all the 7 dynamical second-order transport coefficients for the relativistic fluids dual to compactified AdS black holes of various dimensions via fluid/gravity correspondence. Through this work, we achieve three main goals: (1) We prove that all the gravitational backgrounds that can be used to extract analytical results for second-order transport coefficients hitherto are all Chamblin-Reall type backgrounds. (2) We generalize the results in previous studies on the second-order transport coefficients of the relativistic fluids dual to 5-dimensional Chamblin-Reall model into general dimensions. (3) We offer a thorough study on the Kanitscheider-Skenderis proposal and find its physical accounts., Comment: 38 pages and 2 tables

Published
2021
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20. Second order transport coefficients of nonconformal fluids from compactified Dp-branes

Author

Wu, Chao and Wang, Yanqi

Subjects
High Energy Physics - Theory
Abstract

All the 7 dynamical second order transport coefficients of the nonconformal fluids that correspond to Dp-branes with one or more world-volume directions compactified are derived via fluid/gravity correspondence. The conditions considered in this paper include D4-brane with 1, 2 or 3 compact directions, D3-brane with 1 or 2 compact directions, as well as D2-brane with 1 direction compactified. The derived second order transport coefficients satisfy the Haack-Yarom, Romatschke and Kleinert-Probst relations., Comment: 41 pages, 2 tables

Published
2020
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24. Image and Video Style Transfer Based on Transformer

Author

Sun Fengxue, Sun Yanguo, Lan Zhenping, Wang Yanqi, Zhang Nianchao, Wang Yuru, and Li Ping

Subjects
Encoder, neural network, transformer, style transfer, STLTSF, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

The essence of image style transfer is to generate images that both maintain in the original content image and present the effect with artistic features under the guidance of style images. Deep learning’s quick rise has resulted in even more achievements in image style transfer, an otherwise popular study area. Nevertheless, due to the limitations of Convolutional Neural Networks (CNN), extracting and retaining the input images is problematic. Therefore, image style transfer based on traditional CNN is biased in the representation of content images. To address the above problems, this paper proposes STLTSF (Style Transfer based on Transformer), a transformer-based method that may achieve image style transfer based on the long-range dependencies of the input images. Compared with traditional visual transformers, STLTSF has two different transformer encoders, one for generating domain-specific content and the other for generating styles. We may convert the encoder to a decoding method that can be styled based on content sequences by using numerous layers of transformers. The suggested STLTSF approach outperforms traditional CNN-based methods in both qualitative and quantitative experiments.

Published
2023
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39. Clinical and biomarker analyses of sintilimab versus chemotherapy as second-line therapy for advanced or metastatic esophageal squamous cell carcinoma: a randomized, open-label phase 2 study (ORIENT-2)

Author

Xu, Jianming, Li, Yi, Fan, Qingxia, Shu, Yongqian, Yang, Lei, Cui, Tongjian, Gu, Kangsheng, Tao, Min, Wang, Xiuwen, Cui, Chengxu, Xu, Nong, Xiao, Juxiang, Gao, Quanli, Liu, Yunpeng, Zhang, Tao, Bai, Yuxian, Li, Wei, Zhang, Yiping, Dai, Guanghai, Ma, Dong, Zhang, Jingdong, Bai, Chunmei, Huang, Yunchao, Liao, Wangjun, Wu, Lin, Chen, Xi, Yang, Yan, Wang, Junye, Ji, Shoujian, Zhou, Hui, Wang, Yan, Ma, Zhuo, Wang, Yanqi, Peng, Bo, Sun, Jiya, and Mancao, Christoph

Published
2022
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40. Interplay of symmetry breaking and topological order

Author

Wang, Yanqi

Subjects
Physics, Condensed matter physics, Quantum physics, Algebraic topology, Bulk-edge correspondence and edge network, Quantum dynamics, Quantum spin liquids, Symmetry breaking, Topological phases of matter
Abstract

The two most prevalent classes of ordered states in quantum materials are those arising from spontaneous symmetry breaking (SSB) and from topological order. However, a systematic study for their coexistence in interacting systems is still lacking. In this thesis, we will investigate how the topological configuration in order parameter spaces from SSB interplays with the symmetry protected/enriched topological orders in two spatial dimensions. We start from a phenomenological model of the domain wall structure in chiral spin liquids with domains of opposite chiralities. Based on a standard model, we obtain a spatially varying, self-consistent mean-field solution for the spinons that describes both the gapless edge modes and the change of chirality at the domain wall. We derive the non-universal properties, such as the velocity of the topologically protected domain wall edge states and its modification to domain wall tension. Then we discuss the interplay between topological orders from a more formal point of view. We consider two-dimensional topologically ordered systems with coexisting long-range orders, where the only gapless excitations in the spectrum are Goldstone modes of spontaneously broken continuous symmetries. We show that the universal properties of point defects and textures are determined by the remnant symmetry enriched topological order in the symmetry-breaking ground state with non-fluctuating order parameters, and provide a classification for their properties using algebraic topology. We further investigate the quantum dynamics that can happen at the domain wall of topological orders, where particle-hole scattering leads to linear-in-temperature resistivity of edge modes. Finally, we introduce an effective edge network theory to characterize the boundary topology of coupled edge states generated from various types of topological insulators.

Published
2023

42. High-pressure study on novel structure, mechanical properties and high energy density of RuN4.

Author

Duan, Juyi, Zhang, Jinquan, Wang, Meidi, Tang, Libiao, Wang, Yanqi, Li, Song, Ju, Meng, Jin, Yuanyuan, and Zhang, Chuanzhao

Subjects
ENERGY density, PHASE transitions, VICKERS hardness, EVOLUTIONARY algorithms, CRYSTAL structure, NITROGEN
Abstract

Novel structures with high energy density could be created with the addition of transition-metal elements into polymeric nitrogen. Based on ab initio evolutionary algorithm for crystal structure prediction and first-principles calculations, we have conducted a comprehensive search on the crystal structure of RuN4 under the pressure range of 0−300 GPa and uncovered its pressure-induced phase transition. The consequences indicate that RuN4 decomposes into Ru and N2 under ambient pressure. Subsequently, RuN4 can stabilise with the triclinic P $ \bar{1} $ 1 ¯ -RuN4 phase at 37 GPa, which transforms into the tetragonal P4/mbm-RuN4 structure at 62 GPa. Interestingly, the P $ \bar{1} $ 1 ¯ -RuN4 phase contains RuN6 distorted octahedron and extended chain (N∞), while the P4/mbm-RuN4 structure is composed of RuN8 rectangles and N2 units. Mechanical property analyses have revealed that the P $ \bar{1} $ 1 ¯ -RuN4 and P4/mbm-RuN4 crystals possess high hardness, excellent compression resistance and strong rigidity. Intriguingly, the Vickers hardness value for the P4/mbm RuN4 phase can reach 33.50 GPa. In addition, the electronic structure calculations demonstrate both phases are metallic. Moreover, strong Ru−N and N−N covalent bonds exist in both structures. At ambient conditions, the P4/mbm RuN4 phase has an energy density of 2.81 kJ/g and a volumetric energy density of 18.70 kJ/cm3, which is considered as an excellent high-energy density material. Hence, the P4/mbm RuN4 crystal is a newly multifunctional material that possesses both high hardness and high-energy density. The P4/mbm-RuN4 consists of RuN8 rectangles and N2 polymers. In the RuN8 rectangular unit, the ruthenium atoms occupy the centre of the tetragonal lattice and the upper and lower lateral prisms, and each ruthenium atom is surrounded by eight equally spaced nitrogen atoms. [ABSTRACT FROM AUTHOR]

Published
2024
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