Chinese Physics最新文献

{"title":"Shadow and photon ring of black hole in asymptotically safe gravity","authors":"None Li Hui-Ling, None Huang Yu-Meng, None Yang Cheng-Yu","doi":"10.7498/aps.72.20231233","DOIUrl":"https://doi.org/10.7498/aps.72.20231233","url":null,"abstract":"In this paper, we focus on discussing the influence of thin disk accretion and asymptotically safe (AS) gravity correction parameter on the shadow and photon ring of black holes. For the thin disk accretion, the dark region is the shadow of the black hole, and the bright photon ring is composed of Direct image, lensing ring and Photon ring. For the specific intensity of the radiation source of the accretion disk, we consider three different emission profile models. For the second-order attenuation function model in which emission starts from the innermost circular orbit, Direct image, lensing ring and Photon ring can be clearly distinguished. The Direct image contributes most of the brightness, and the lensing ring contributes a small portion, while the contribution of the Photon ring can almost be ignored. And the peak value of the corresponding observed intensity decreases with the increase of the AS gravity parameter, that is, the corresponding brightness of the photon ring darkens as correction parameter increases. For the third-order attenuation function model in which the emission begins at the radius of the photon sphere, lensing ring and Photon ring are superimposed on the direct radiation. Thus a new extreme value of the observed intensity emerges, and the extreme value increases with the increase of the AS gravity parameter, which leads to observed photon ring brighter. For the anti-trigonometric attenuation function model in which the radiation starts from the event horizon, the superposition range of lensing ring and Photon ring on the direct radiation becomes larger, which makes photon ring wider. The smaller the AS gravity parameter is, the more difficult it is to distinguish the lensing ring and Photon ring, and the photon ring gets brighter. In short, the results show that the shadow radius decreases with the increase of the AS correction parameter. For different AS gravity correction parameters, the light intensity of emission source, especially emission profiles of the observed intensity are significantly different, resulting in obvious differences for the shadow and bright photon ring of the black hole.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136202698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on space charge packet migration combining the electron beam irradiation technique and real-time space charge distribution measurement by piezo-PWP method","authors":"None Pan Jiaping, None Zhang Yewen, None Li Jun, None Lv Tihua, None Zheng Feihu","doi":"10.7498/aps.73.20231353","DOIUrl":"https://doi.org/10.7498/aps.73.20231353","url":null,"abstract":"The space charge packet is a special sort of space charge phenomenon that is characterized by the migration of aggregated space charge in the form of a packet within the sample. Currently, most of the experimental and simulation studies on the generation and migration of space charge packets are focused on the space charge packets with positive polarity in polyethylene and its cross-linking products, while the characteristics of the space charge packets with negative polarity are yet to be studied. This paper presents an integrated experimental system for the researches on space charge packet with negative polarity, which enables experimental studies combining electron beam irradiation technique and real-time space charge distribution measurement. The beam flux for electron beam irradiation is controlled by a metal grid with an optical fiber-electric relay and the space charge distribution measurement is performed by the piezo- pressure wave propagation method. The system achieves a withstand voltage value of 17 kV and a measuring resolution of 25 ns for space charge distribution measurement and is suitable for experimental studies of various material samples with different thickness ranges under different electric fields. In this paper, the migration behavior of space charge packets with negative polarity in polypropylene (PP) and polymethyl methacrylate (PMMA) samples under different applied electric field (15-20-25-30 kV/mm) were studied using the experimental system. The relationship between the migration properties of carriers with negative polarity (electrons) and the electric field can be extracted from the experimental results. The \"negative differential mobility\" phenomenon was found for both materials, i.e., the migration rate decreases with the increase of the electric field. The threshold electric field for the \"negative differential mobility\" phenomenon of electrons in PP samples is about 26.0 kV/mm while the threshold electric field for the \"negative differential mobility\" phenomenon of electrons in PMMA samples is 19.5 kV/mm and the phenomenon disappears at an electric field of 27.5 kV/mm. The electric field where the \"negative differential mobility\" phenomenon of electrons appears and disappears within different materials can be extracted using the experimental system proposed in this paper.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136202984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of laser induced discharge plasma and its extreme ultraviolet radiation","authors":"None Wang Jun-Wu, None Xuan Hong-Wen, None Yu Hang-Hang, None Wang Xin-Bing, None Vassily S. Zakharov","doi":"10.7498/aps.73.20231158","DOIUrl":"https://doi.org/10.7498/aps.73.20231158","url":null,"abstract":"Laser induced discharge plasma is one of the important technical means for extreme ultraviolet light source. In this paper, a radiation magneto-hydrodynamic model based on a global equation of state model, an atomic structure calculation model and a collision radiation model is proposed to simulate the dynamic characteristics of laser induced discharge plasma and its extreme ultraviolet radiation characteristics. The simulation reproduced the pinch phenomenon during the discharge process, and the conversion efficiency of extreme ultraviolet light obtained was consistent with the experiment result.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136202995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced production of <sup>199</sup>Hg cold atoms based on two-dimensional magneto-optical trap","authors":"None Yu Ze-Xin, None Liu Qi-Xin, None Sun Jian-Fang, None Xu Zhen","doi":"10.7498/aps.73.20231243","DOIUrl":"https://doi.org/10.7498/aps.73.20231243","url":null,"abstract":"Efficient preparation of cold atoms plays an important role in the precision measurement including optical lattice clocks (OLCs). Fast preparation of cold atoms reduces Dick noise by shortening dead time in a clock interrogation cycle, which improves the stability of OLCs. Here, we increase the loading rate of the three-dimensional magneto-optical trap (3D-MOT) in the ultra-high vacuum environment by utilizing the two-dimensional magneto-optical trap (2D-MOT) with a push beam, reduce the temperature of cold atoms with the compressing-MOT technique which is implemented by decreasing the detuning of 3D-MOT rapidly at the end of atom preparation, and realize the enhanced production of cold atoms for ¹⁹⁹Hg OLCs. To achieve 3D-MOT and 2D-MOT of mercury atoms, a deep ultraviolet laser (DUVL) system composed of three DUVLs is developed with one working in lower power for frequency locking and the other two in high power for laser cooling. Such configuration improves the long-term frequency stability and shows greater robustness than our previous system consisting of two DUVLs. To maximize the 3D-MOT loading rate, we orderly optimize the detuning and the magnetic field gradient of 3D-MOT and those of 2D-MOT as well as the detuning and the power of the push beam. After the optimization of all parameters, we measure the maximum loading rate of 3D-MOT to be 3.1×10⁵/s and prepare cold atoms of 1.8×10⁶ in 9 s. The loading rate is greatly enhanced by a factor of 51 with 2D-MOT and the push beam. To improve the efficiency that cold atoms transfer from 3D-MOT to optical lattice, we use the compressing-MOT technique to reduce the temperature of cold atoms and produce cold ¹⁹⁹Hg atoms of about 45 μK, below the temperature expected by Doppler cooling theory. By achieving the high gain of the 3D-MOT loading rate under the ultra-high vacuum and reducing the temperature of cold atoms, this enhanced preparation of cold atoms based on 2D-MOT effectively shortens the preparation time of cold atoms and improves the transfer efficiency of optical lattice, which provides a significant scheme for the efficient preparation of cold mercury atoms in other experiments.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136203344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on The Technology of Optical Fiber High-Temperature Pressure Sensor with Weak Temperature Sensitivity","authors":"None Wang Wei, None Li Jin-Yang, None Mao Guo-pei, None Yang Yan, None Gao Zhi-Qiang, None Ma Cong, None Zhong Xiang-yu, None Shi Qing","doi":"10.7498/aps.73.20231155","DOIUrl":"https://doi.org/10.7498/aps.73.20231155","url":null,"abstract":"In aerospace, petrochemical, gas turbines and other high-temperature environments, pressure measurement of equipment has always been a challenge to be solved. The electrical high temperature pressure sensor has the problem of component failure in the high temperature environment, and it is difficult to use in the high temperature environment for a long time. The detection device of the optical fiber sensor does not include electrical components, so it has the advantages of high working temperature, high measurement accuracy, anti-electromagnetic interference and so on. In order to measure pressure in high temperature environment with sensor, a temperature-weakly sensitive optical fiber Micro-Electro-Mechanical System (MEMS) pressure sensing technology is proposed. The technique uses Extrisic Fabry-Perot Interference (EFPI) model. It uses the MEMS pressure chip to passively modulate the optical signal of the interference, and then realizes the pressure signal measurement. Among them, MEMS pressure sensitive chip is the core component of the sensor. The MEMS pressure sensitive chip adopts the design method of all solid state vacuum absolute pressure. Changes in environmental pressure will deform the membrane. This phenomenon can cause changes in the cavity of the EFPI cavity. Therefore, stress information can be obtained by measuring changes in EFPI cavity. The thermal stress and temperature parasitical response introduced by thermal expansion of the material are calculated by simulation. The influence of temperature signal on chip displacement is analyzed by the above results. On this basis, combined with the sub-micron white light interference response technology and low thermal stress packaging technology, the high temperature pressure sensor prototype is developed. In order to test the actual measurement ability of the sensor, this paper does the pressure test and high temperature test respectively. When the pressure changes from 0kpa to 100kpa, the spectral intensity of the sensor output has a linear relationship with the pressure. During the temperature change from 20℃ to 400℃, the spectral intensity of the sensor output did not change significantly. The experimental test results show that the pressure measurement of 0~100kPa can be satisfied in the range of 20~400℃, and the measurement error introduced by temperature change is less than 4%. Therefore, the fiber pressure sensor can be used to measure pressure in high temperature environment.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136053983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The carrier ladder effect regulates the dissociation and scattering of the triplet excitons in OLED","authors":"None Bao Xi, None Guan Yun-Xia, None Li Wan-jiao, None Song Jian-Yi, None Chen Li-jia, None Xu Shuang, None Peng ke-Ao, None Niu Lian-Bin","doi":"10.7498/aps.72.20230851","DOIUrl":"https://doi.org/10.7498/aps.72.20230851","url":null,"abstract":"Triplet exciton-charge interaction (TQI) has two forms: dissociation and scattering, However, it is still unclear how the hole injection layer affects the dissociation and scattering of triplet excition and the transition between positive and negative values of magneto-conductance (MC). In this paper, HAT-CN, which can produce carrier ladder effect, is used as hole injection layer (HIL), and magnetic effect is used as a tool to study it. The results show that there are three characteristic magnetic fields in the device: hyperfine, dissociation and scattering, which are verified by fitting the MC with Lorentzian and non-Lorentzian functions. The hyperfine characteristic magnetic field results from the magnetic field suppressing superfine field-induced charge-spin mixing. With the enhancement of magnetic field, hole injection layer/hole transport layer interface produces carrier ladder effect, which improves the hole injection efficiency. The triplet excitions are separated by the hole, then the secondary carriers are produced, which makes the device’s luminous brightness and efficiency reach to 43210 cd/m² and 9.8 cd/A, respectively. The carrier ladder effect will also lead to a large accumulation of injected charges, resulting in the scattering of charge carriers by triplet excition, thereby reducing their mobility, which is not conducive to the formation of excited states nor device luminescence. The MC is modulated by <i>K</i>_S/<i>K</i>_T (recombination rate ratio), and when the electric field is small <inline-formula><tex-math id=\"M5\">begin{document}$ {K}_{{rm{S}}}gg {K}_{{rm{T}}} $end{document}</tex-math><alternatives><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"21-20230851_M5.jpg\"/><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"21-20230851_M5.png\"/></alternatives></inline-formula>, the recombination ratio is relatively large, resulting in positive MC. With the increase of electric field <inline-formula><tex-math id=\"M6\">begin{document}$ {K}_{{rm{S}}}approx {K}_{{rm{T}}}=K$end{document}</tex-math><alternatives><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"21-20230851_M6.jpg\"/><graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"21-20230851_M6.png\"/></alternatives></inline-formula>, <i>K</i>_S/<i>K</i>_T approaches 1 at this time, resulting in an MC, which is negative in a low temperature environment. This work provides a novel approach for regulating and effectively utilizing triplet excitons.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136299258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preface to the special topic: Energetic particles in magnetic confinement fusion","authors":"","doi":"10.7498/aps.72.210101","DOIUrl":"https://doi.org/10.7498/aps.72.210101","url":null,"abstract":"","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135152840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-Equilibrium Quantum Many-body Physics with Ultracold Atoms","authors":"None Hui Zhai","doi":"10.7498/aps.72.20231375","DOIUrl":"https://doi.org/10.7498/aps.72.20231375","url":null,"abstract":"Combining quantum many-body physics and nonequilibrium physics is an important opportunity and challenge for current physics research. Nonequilibrium quantum many-body physics is not only a subject of common interest to many branches of physics but also an indispensable theoretical foundation for developing emergent quantum technologies. Cold atom system provides an ideal platform for studying nonequilibrium quantum many-body physics. The advantages of cold atom system, as well as other synthetic quantum systems, are reflected in studying various nonequilibrium processes such as the thermalization of isolated system, dissipation induced by coupling to the environment, ramping, quench, or periodically driving physical parameters of a system. In this work, three examples from our research are discussed to show how the study of nonequilibrium quantum many-body physics with cold atoms can help us go beyond the existing framework of topological physics, uncover new methods of detecting quantum many-body correlations, and enrich the physical content of gauge theory. Such a research concerns the fundamental properties of quantum many-body system, such as topology and correlation, utilizes the advantages of cold atomic system to achieve a quantitative comparison between theory and experiment, and aims at discovering universal physical rules for nonequilibrium quantum many-body process, which can be extended to condensed matter and nuclear matter systems.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135319608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Encoding terahertz metasurface reflectors based on Geometrical phase Modulation","authors":"None Jiang Zai-chao, None Gong Zheng, None Zhong Yunxiang, None Cui Bin, None Zou Bin, None Yang Yu-Ping","doi":"10.7498/aps.72.20230989","DOIUrl":"https://doi.org/10.7498/aps.72.20230989","url":null,"abstract":"Multi-dimension and freedom modulation of polarization state based on the geometrical-phase periodic encoding metasurface has important application prospects. Here, terahertz metasurfaces composed of specially shaped metal pattern coded particles are proposed. When the coded particles are normally incident, the amplitude reflectivity of the terahertz wave is above 80% in the range of 0.50-1.80 THz. Combined with the Pancharatnam-Berry (P-B) phase theory, 8 kinds of coded particles are designed by rotating the angle of the designed unit. Three kinds of 1-bit, 2-bit, and 3-bit periodic encoding metasurfaces with different encoding sequences are used to manipulate the reflected terahertz waves splitting into multiple-beam with different deflection angles. In addition, both reflection characteristics (including amplitude, phase, phase coverage, etc) of all coded particles and the angle deflection of the designed 2-bit periodic metasurface have been measured by normal incidence and variable angle THz time-domain spectrometers, respectively. The reason for the deviation between theoretical and experimental values has been further analyzed based on generalized Snell law and experimental results, which can provide a reference for reverse design of the coded metasurfaces to aim at various practical needs.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135400182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperfine structure constants and &lt;i&gt;g&lt;/i&gt; factors of clock-states of Al-like ions","authors":"None Wang Xia, None Jia Fang-shi, None Yao Ke, None Yan Jun, None Li Ji-Guang, None Wu Yong, None Wang Jian-Guo","doi":"10.7498/aps.72.20230940","DOIUrl":"https://doi.org/10.7498/aps.72.20230940","url":null,"abstract":"The highly charged Al-like ions are the potential candidates for the next-generation atomic optical clocks, and their atomic parameters are also useful in plasma and nuclear physics. In the present work, the hyperfine interaction constants and Landé <i>g</i> factors of 3s²3p ²P_{1/2, 3/2} states in the ground configuration for Al-like ions in a range between Si⁺ and Kr²³⁺ ions are calculated by using the multi-configuration Dirac-Hartree-Fock method. Owing to the fact that hyperfine interaction constant is sensitive to electron correlation effect, we systematically investigate its influence on the hyperfine interaction constants, particularly for the high-order correlation related to the 2p electrons. According to this investigation and by taking into account the Breit interaction and QED corrections, we achieve the computational accuracy at a level of 1% and 10^–5 for the hyperfine interaction constant and Landé <i>g</i> factor, respectively, except for Si⁺ ion. Furthermore, the electronic part of hyperfine interaction constant and <i>g</i> factor each as a function of atomic number are obtained. The deviations of the hyperfine structure constant and <i>g</i> factor from these fitted formulas from the <i>ab initio</i> calculations are less than 2% and 10^–5, respectively. As a result, the hyperfine structure constants and <i>g</i> factors of all isotopes can be determined for Al-like ions with 14 ≤ <i>Z</i> ≤ 54.","PeriodicalId":10252,"journal":{"name":"Chinese Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135400735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}