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Revealing excited states of rotational Bose-Einstein condensates

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The Innovation 2024年第1期5卷 41-48页

作者： Jianyuan Yin Zhen Huang Yongyong Cai Qiang Du Lei Zhang School of Mathematical Sciences Laboratory of Mathematics and Applied MathematicsPeking UniversityBeijing 100871China Department of Mathematics National University of SingaporeSingapore 119076Singapore Department of Mathematics University of CaliforniaBerkeleyBerkeleyCA 94720USA School of Mathematical Sciences Beijing Normal UniversityBeijing 100875China Department of Applied Physics and Applied Mathematics and Data Science Institute Columbia UniversityNew YorkNY 10027USA Beijing International Center for Mathematical Research Center for Quantitative BiologyCenter for Machine Learning ResearchPeking UniversityBeijing 100871China

Rotational Bose-Einstein condensates can exhibit quantized vortices as topological *** this study,the ground and excited states of the rotational Bose-Einstein condensates are systematically studied by calculating the stationary points of the Gross-Pitaevskii energy *** excited states and their connections at different rotational frequencies are revealed in solution landscapes constructed with the constrained high-index saddle dynamics *** excitation mechanisms are identified:vortex addition,rearrangement,merging,and *** demonstrate changes in the ground state with increasing rotational frequencies and decipher the evolution of the stability of ground states.

关键词： method rotational excited

From Euler disk to phonon bottleneck effect: excited state physics

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The Innovation 2024年第3期5卷 7-8页

作者： Xinnian Lin Shaohua Fu Yanni Zhai Wenhui Wang Haochen Li Ruizhi Zhang Sheng Meng Jimin Zhao School of Physics Xi’an Jiaotong UniversityXi’an 710049China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China

The Euler disk,known since 1765,1 describes a solid disk that rotates on a smooth,firm surface,similar to a coin spun by a finger on a table,before its energy dissipates and it falls on the table.2 It represents a typical nonequilibrium excited state in classical *** most striking characteristic of an Euler disk is that it exhibits a sharply enhanced sound frequency when approaching the critical time,tc,after which the disk instantly ceases rotation and *** the excited-state-to-ground-state transition,its frequency abruptly changes from infinite to *** quasi-divergent and suddenly disappearing behavior is intriguing,revealing that this is a shared physical property in the microscopic quantum regime.

关键词： state excited sharply

excited STATE STIMULATED RAMAN SCATTERING FROM SODIUM VAPOR

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Chinese Physics Letters 1989年第1期6卷 12-15页

作者： WANG Shumin QIAN Shixiong LI Yufen Physics Department Fudan UniversityShanghai

Under the Na vapor,states was near resonant radiation field-atom interaction in large population difference between 3^(2)P_(1/2)and 3^(2)P_(3/2)generated,then occurred the excited state stimulated Raman Scattering(ESSRS).By the sequential four-wave mixing(FWM)process,multi-line ESSRS and the buffer gas effeet have been observed.A theory has been developed to explain the experimental results.

关键词： resonant excited mixing

Enhanced blue-light excited cyan-emitting persistent luminescence of BaLu_(2)Al_(2)Ga_(2)SiO_(12)∶Ce3+,Bi3+phosphors for AC-LEDs via defect modulation

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Light(Science & Applications) 2022年第7期11卷 1542-1554页

作者： Weihong Yuan Ran Pang Shangwei Wang Tao Tan Chengyu Li Chaowei Wang Hongjie Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China Hefei 230026China Zhongke Rare Earth(Guangzhou)Co. LtdGuangzhou 510700China

Alternating current light-emitting diodes(AC-LEDs)have received significant attention from both academia and industry due to their remarkable benefits of more compact volume,cheaper manufacturing cost,greater energy usage efficiency,and longer service *** of the most significant challenges for AC-LEDs is the flicker effect,which is mainly caused by the unavoidable 5-20 ms dimming *** to reduce the flicker effect,we designed a series of excellent blue-light excited cyan-emitting persistent luminescence(PersL)phosphors BaLu_(2)Al_(2)Ga_(2)SiO_(12)∶Ce^(3+),Bi^(3+)via defect engineering of co-doping Bi^(3+).Interestingly,we found that co-doping Bi^(3+)not only effectively enhanced the PersL intensity,but also regulated the PersL lifetime of this *** the Bi^(3+)co-doping concentration increases to 0.01,the T80 value(the time when the PersL intensity decreases to 80%of the initial intensity)increases from 0.24 to 19.61 ms,which proves to be effective in compensating the flicker effect of AC-LEDs.A new method of generating white light emission during the dimming time through adding the blue-light excited cyan PersL phosphor to the original orange-red PersL phosphor was proposed and an AC-LED lamp with a decreased percent flicker of 48.15%was fabricated,which is significantly better than the other currently reported AC-LED devices based on PersL *** results demonstrate that BaLu_(2)Al_(2)Ga_(2)SiO_(12):Ce^(3+),Bi^(3+)might be an attractive material for low-flicker AC-LEDs.

关键词： excited luminescence defect

excited State Properties of Fucoxanthin Aggregates

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Chemical Research in Chinese Universities 2019年第4期35卷 627-635页

作者： ZUO Jialing TAN Liming XU Yi MA Yingchao DONG Jia WANG Peng ZHANG Jianping Department of Chemistry Renmin University of China Beijing 100872 P. R. China

The structure and excited state properties of the H- and J-aggregates of the marine carbonyl carotenoid, fucoxanthin(Fx), were studied by various spectroscopic methods, and compared with those of Fx monomers in polar organic solvents. The fluorescent analysis indicated tliat the higher vibronic states of S2 contribute more to populating the S1 state, from which fluorescent emission mainly originates. Resonance Raman and density functional theory calculations confirmed the ‘card-packed' and chead-to-taiF structures of the H- and J-aggregates of Fx, respectively. An fs time-resolved absorption study proved the coexistence of Si and intramolecular charge transfer relaxation pathways upon excitation to the S2 state for both tlie monomers and aggregates.

关键词： Fucoxanthin aggregate Resonance Raman fs Time-resolved absorption excited state property Singlet fission

Data-driven models for ground and excited states for Single Atoms on Ceria

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npj Computational Materials 2022年第1期8卷 1636-1643页

作者： Julian Geiger Albert Sabadell-Rendón Nathan Daelman Núria López Institute of Chemical Research of Catalonia(ICIQ) The Barcelona Institute of Science and Technology(BIST)Avinguda Països Catalans 1643007TarragonaSpain Universitat Rovira i Virgili Avinguda Catalunya3543002TarragonaSpain

Ceria-based single-atom catalysts present complex electronic structures due to the dynamic electron transfer between the metal atoms and the semiconductor oxide *** these materials implies retrieving all states in these electronic ensembles,which can be limiting if done via density functional ***,we propose a data-driven approach to obtain a parsimonious model identifying the appearance of dynamic charge transfer for the single atoms(SAs).We first constructed a database of(701)electronic configurations for the group 9–11 metals on CeO_(2)(100).Feature Selection based on predictive Elastic Net and Random Forest models highlights eight fundamental variables:atomic number,ionization potential,size,and metal coordination,metal–oxygen bond strengths,surface strain,and Coulomb *** these variables a Bayesian algorithm yields an expression for the adsorption energies of SAs in ground and low-lying excited *** work paves the way towards understanding electronic structure complexity in metal/oxide interfaces.

关键词： theory excited states

The critical role of hot carrier cooling in optically excited structural transitions

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npj Computational Materials 2021年第1期7卷 1061-1066页

作者： Wen-Hao Liu Jun-Wei Luo Shu-Shen Li Lin-Wang Wang State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijingChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Beijing Academy of Quantum Information Sciences BeijingChina Materials Science Division Lawrence Berkeley National LaboratoryBerkeleyCAUSA

The hot carrier cooling occurs in most photoexcitation-induced phase transitions(PIPTs),but its role has often been neglected in many theoretical simulations as well as in proposed ***,by including the previously ignored hot carrier cooling in real-time time-dependent density functional theory(rt-TDDFT)simulations,we investigated the role of hot carrier cooling in *** IrTe2 as an example,we reveal that the cooling of hot electrons from the higher energy levels of spatially extended states to the lower energy levels of the localized Ir–Ir dimer antibonding states strengthens remarkably the atomic driving forces and enhances atomic kinetic *** two factors combine to dissolute the Ir–Ir dimers on a timescale near the limit of atomic motions,thus initiating a deterministic kinetic phase *** further demonstrate that the subsequent cooling induces nonradiative recombination of photoexcited electrons and holes,leading to the ultrafast recovery of the Ir–Ir dimers observed *** findings provide a complete picture of the atomic dynamics in optically excited structural phase transitions.

关键词： transition excited transitions

Ab initio investigation of excited state dual hydrogen bonding interactions and proton transfer mechanism for novel oxazoline compound

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Chinese Physics B 2019年第10期28卷 309-314页

作者： Yu-Sheng Wang Min Jia Qiao-Li Zhang Xiao-Yan Song Da-Peng Yang College of Physics and Electronics North China University of Water Resources and Electric PowerZhengzhou 450046China State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Owing to the importance of excited state dynamical relaxation, the excited state intramolecular proton transfer(ESIPT) mechanism for a novel compound containing dual hydrogen bond(abbreviated as "1-enol") is studied in this *** density functional theory(DFT) and time-dependent density functional theory(TDDFT) method, the experimental electronic spectra can be reproduced for 1-enol compound. We first verify the formation of dual intramolecular hydrogen bonds, and then confirm that the dual hydrogen bond should be strengthened in the first excited state. The photo-excitation process is analyzed by using frontier molecular orbital(HOMO and LUMO) for 1-enol compound. The obvious intramolecular charge transfer(ICT) provides the driving force to effectively facilitate the ESIPT process in the S1 state. Exploration of the constructed S0-state and S1-state potential energy surface(PES) reveals that only the excited state intramolecular single proton transfer occurs for 1-enol system, which makes up for the deficiencies in previous experiment.

关键词： excited state intramolecular proton transfer potential energy surface intramolecular charge transfer infrared vibrational spectra

Ground States and excited States in a Tunable Graphene Quantum Dot

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Chinese Physics Letters 2011年第6期28卷 248-250页

作者： WANG Lin-Jun CAO Gang TU Tao LI Hai-Ou ZHOU Cheng HAO Xiao-Jie GUO Guang-Can GUO Guo-Ping Key Laboratory of Quantum Information University of Science and Technology of ChinaChinese Academy of SciencesHefei 230026

We prepare an etched gate tunable quantum dot in single-layer graphene and present transport measurement in this *** extract the information of the ground states and excited states of the graphene quantum dot,as denoted by the presence of characteristic Coulomb blockade diamond *** results demonstrate that the quantum dot in single-layer graphene bodes well for future quantum transport study and quantum computing applications.

关键词： quantum excited states