IF 1.8

Atoms Pub Date : 2023-07-06 DOI: 10.3390/atoms11070102

Yongchang Zhang, F. Maucher

引用次数: 1

Mean-Field Description of Cooperative Scattering by Atomic Clouds 原子云协同散射的平均场描述

IF 1.8

Atoms Pub Date : 2023-06-29 DOI: 10.3390/atoms11070101

N. Piovella

引用次数: 1

Decay of Persistent Currents in Annular Atomic Superfluids 环形原子超流体中持续电流的衰减

IF 1.8

Atoms Pub Date : 2023-06-20 DOI: 10.3390/atoms11080109

K. Xhani, G. Del Pace, F. Scazza, G. Roati

{"title":"Decay of Persistent Currents in Annular Atomic Superfluids","authors":"K. Xhani, G. Del Pace, F. Scazza, G. Roati","doi":"10.3390/atoms11080109","DOIUrl":"https://doi.org/10.3390/atoms11080109","url":null,"abstract":"We investigate the role of vortices in the decay of persistent current states of annular atomic superfluids by solving numerically the Gross–Pitaevskii equation, and we directly compare our results with the 6Li experiment at LENS data. We theoretically model the optical phase-imprinting technique employed to experimentally excite finite-circulation states in the Bose–Einstein condensation regime, accounting for imperfections of the optical gradient imprinting profile. By comparing simulations of this realistic protocol to an ideal imprinting, we show that the introduced density excitations arising from imperfect imprinting are mainly responsible for limiting the maximum reachable winding number wmax in the superfluid ring. We also investigate the effect of a point-like obstacle with variable potential height V0 on the decay of circulating supercurrents. For a given obstacle height, a critical circulation wc exists, such that for an initial circulation w0 larger than wc the supercurrent decays through the emission of vortices, which cross the superflow and thus induce phase slippage. Higher values of the obstacle height V0 further favor the entrance of vortices, thus leading to lower values of wc. Furthermore, the stronger vortex-defect interaction at higher V0 leads to vortices that propagate closer to the center of the ring condensate. The combination of both these effects leads to an increase in the supercurrent decay rate for increasing w0, in agreement with experimental observations.","PeriodicalId":8629,"journal":{"name":"Atoms","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42663710","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}

引用次数: 3

Scattering of X-ray Ultrashort Laser Pulses on Bound Electrons in Dense Plasma x射线超短激光脉冲在致密等离子体中束缚电子上的散射

IF 1.8

Atoms Pub Date : 2023-06-16 DOI: 10.3390/atoms11060100

E. Khramov, V. Astapenko

引用次数: 0

Neutron Interferometer Experiments Studying Fundamental Features of Quantum Mechanics 研究量子力学基本特征的中子干涉仪实验

IF 1.8

Atoms Pub Date : 2023-06-15 DOI: 10.3390/atoms11060098

Armin Danner, H. Lemmel, R. Wagner, S. Sponar, Y. Hasegawa

{"title":"Neutron Interferometer Experiments Studying Fundamental Features of Quantum Mechanics","authors":"Armin Danner, H. Lemmel, R. Wagner, S. Sponar, Y. Hasegawa","doi":"10.3390/atoms11060098","DOIUrl":"https://doi.org/10.3390/atoms11060098","url":null,"abstract":"Quantum theory provides us with the best account of microscopic components of matter as well as of radiation. It was introduced in the twentieth century and has experienced a wide range of success. Although the theory’s probabilistic predictions of final experimental outcomes is found to be correct with high precision, there is no general consensus regarding what is actually going on with a quantum system “en route”, or rather the perceivable intermediate behavior of a quantum system, e.g., the particle’s behavior in the double-slit experiment. Neutron interferometry using single silicon perfect crystals is established as a versatile tool to test fundamental phenomena in quantum mechanics, where an incident neutron beam is coherently split in two or three beam paths with macroscopic separation of several centimeters. Here, we present quantum optical experiments with these matter-wave interferometers, studying the effect of the quantum Cheshire Cat in some variants, the neutron’s presence in the paths of the interferometer as well as the direct test of a commutation relation. To reduce disturbances induced by the measurement, the interaction strength is lessened and so-called weak interactions are exploited by employing pre- and post-selection procedures. All results of the experiments confirm the predictions of quantum theory; the observed behaviors of the neutron between the pre- and post-selection in space and time emphasize striking and counter-intuitive aspects of quantum theory.","PeriodicalId":8629,"journal":{"name":"Atoms","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48200877","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}

引用次数: 1

Measurement of the Tensor-Analyzing Power Component T20 for Incoherent Negative Pion Photoproduction on a Deuteron 氘上非相干负质子光产生的张量分析功率分量T20的测量

IF 1.8

Atoms Pub Date : 2023-06-15 DOI: 10.3390/atoms11060099

A. Kuzmenko, V. Gauzshtein, E. Darwish, A. Fix, M. Kuzin, M. Levchuk, A. Loginov, D. Nikolenko, I. Rachek, Y. Shestakov, D. Toporkov, A. Yurchenko, B. Vasilishin, S. Zevakov

引用次数: 1

Pulse Cycle Dependent Nondipole Effects in Above-Threshold Ionization 阈值以上电离中脉冲周期相关的非偶极子效应

IF 1.8

Atoms Pub Date : 2023-06-12 DOI: 10.3390/atoms11060097

Danish Furekh Dar, S. Fritzsche

引用次数: 0

Structure and Bonding Patterns in C5H4 Isomers: Pyramidane, Planar Tetracoordinate Carbon, and Spiro Molecules C5H4异构体的结构和键合模式：吡喃、平面四配位碳和螺环分子

IF 1.8

Atoms Pub Date : 2023-06-10 DOI: 10.3390/atoms11060096

Sayon Satpati, T. Roy, Sandip Giri, A. Anoop, Venkatesan S. Thimmakondu, S. Ghosal

{"title":"Structure and Bonding Patterns in C5H4 Isomers: Pyramidane, Planar Tetracoordinate Carbon, and Spiro Molecules","authors":"Sayon Satpati, T. Roy, Sandip Giri, A. Anoop, Venkatesan S. Thimmakondu, S. Ghosal","doi":"10.3390/atoms11060096","DOIUrl":"https://doi.org/10.3390/atoms11060096","url":null,"abstract":"We have theoretically investigated nine unusual isomers of the molecular formula C5H4 using coupled cluster (CC) and density functional theory (DFT) methods. These molecules possess non-classical structures consisting of two pyramidanes, three planar tetracoordinate carbon (ptC), and four spiro types of isomers. Both the pyramidanes (tetracyclo-[2.1.0.01,3.02,5]pentane; py-1 and tricyclo-[2.1.0.02,5]pentan-3-ylidene; py-2) are minima on the potential energy surface (PES) of C5H4. Among the three isomers containing ptC, (SP4)-spiro [2.2]pent-1-yne (ptC-2) is a minimum, whereas isomer, (SP4)-spiro [2.2]pent-1,4-diene (ptC-1) is a fourth-order saddle point, and (SP4)-sprio[2.2]pent-1,4-diylidene (ptC-3) is a transition state. The corresponding spiro isomers spiro[2.2]pent-1,4-diene (spiro-1), sprio[2.2]pent-1,4-diylidene (spiro-3) and spiro[2.2]pent-4-en-1-ylidene (spiro-4) are local minima, except spiro[2.2]pent-1-yne (spiro-2), which is a second-order saddle point. All relative energies are calculated with respect to the global minimum (pent-1,3-diyne; 1) at the CCSD(T)/cc-pVTZ level of theory. Quantum chemical calculations have been performed to analyze the bonding and topological configurations for all these nine isomers at the B3LYP/6-311+G(d,p) level of theory for a better understanding of their corresponding electronic structures. ptC-2 was found to be thermodynamically more stable than its corresponding spiro counterpart (spiro-2) and possesses a high dipole moment (μ = 4.64 D). The stability of the ptC structures with their higher spin states has been discussed.","PeriodicalId":8629,"journal":{"name":"Atoms","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47074064","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}

引用次数: 1

Improved Line Intensity Analysis of Neutral Helium by Incorporating the Reabsorption Processes in a Helium Collisional-Radiative Model 结合氦碰撞-辐射模型中重吸收过程的中性氦谱线强度改进分析

IF 1.8

Atoms Pub Date : 2023-06-08 DOI: 10.3390/atoms11060094

K. Lin, M. Goto, H. Akatsuka

{"title":"Improved Line Intensity Analysis of Neutral Helium by Incorporating the Reabsorption Processes in a Helium Collisional-Radiative Model","authors":"K. Lin, M. Goto, H. Akatsuka","doi":"10.3390/atoms11060094","DOIUrl":"https://doi.org/10.3390/atoms11060094","url":null,"abstract":"In this study, eight emission lines in the visible wavelength range of neutral helium were used to diagnose the electron density and temperature of the Large Helical Device (LHD) helium plasma instead of the conventional three-line method. The collisional-radiative (CR) model for low-pressure helium plasma was revised to include the optical escape factors for spontaneous transition from the n1P states to the ground state so that the influence of the absorption effect under optically thick conditions could be considered. The developed algorithm was based on fitting the number densities of eight excited states obtained using optical emission spectroscopy (OES). The electron density, electron temperature, ground-state density, and optical escape factors were selected as the fitting parameters. The objective function was set as the summation of the residual errors between the number densities measured in the experiment and those calculated using the revised model. A regularization term was introduced for the optical escape factor and optimized through bias and variance analyses. The results show that the agreement between the number density calculated by the algorithm and its counterpart measured in the experiment was generally improved compared to the method using three lines.","PeriodicalId":8629,"journal":{"name":"Atoms","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49151681","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}

引用次数: 0

Editorial of the Special Issue “General Relativistic Atomic Structure Program—GRASP” 《广义相对论原子结构程序-把握》特刊社论

IF 1.8

Atoms Pub Date : 2023-06-06 DOI: 10.3390/atoms11060093

J. Bieroń, C. Fischer, P. Jönsson

引用次数: 0

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