IF 1.8

Atoms Pub Date : 2023-07-22 DOI: 10.3390/atoms11070107

J. Sims, B. Padhy, María Belén Ruiz Ruiz

{"title":"Exponentially Correlated Hylleraas–Configuration Interaction Studies of Atomic Systems. III. Upper and Lower Bounds to He-Sequence Oscillator Strengths for the Resonance 1S→1P Transition","authors":"J. Sims, B. Padhy, María Belén Ruiz Ruiz","doi":"10.3390/atoms11070107","DOIUrl":"https://doi.org/10.3390/atoms11070107","url":null,"abstract":"The exponentially correlated Hylleraas–configuration interaction method (E-Hy-CI) is a generalization of the Hylleraas–configuration interaction method (Hy-CI) in which the single rij of an Hy-CI wave function is generalized to a form of the generic type rijνije−ωijrij. This work continues the exploration, begun in the first two papers in this series (on the helium atom and on ground and excited S states of Li II), of whether wave functions containing both linear and exponential rij factors converge more rapidly than either one alone. In the present study, we examined not only 1s2 1S states but 1s2p 1P states for the He I, Li II, Be III, C V and O VII members of the He isoelectronic sequence as well. All 1P energies except He I are better than previous results. The wave functions obtained were used to calculate oscillator strengths, including upper and lower bounds, for the He-sequence lowest (resonance) 1S→1P transition. Interpolation techniques were used to make a graphical study of the oscillator strength behavior along the isoelectronic sequence. Comparisons were made with previous experimental and theoretical results. The results of this study are oscillator strengths for the 1s2 1S→ 1s2p1P He isoelectronic sequence with rigorous non-relativistic quantum mechanical upper and lower bounds of (0.001–0.003)% and probable precision ≤ 0.0000003, and were obtained by extending the previously developed E-Hy-CI formalism to include the calculation of transition moments (oscillator strengths).","PeriodicalId":8629,"journal":{"name":"Atoms","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2023-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45323309","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

Towards Understanding Incomplete Fusion Reactions at Low Beam Energies: Modified Sum Rule Model 理解低束流能量下的不完全聚变反应:修正和规则模型

IF 1.8

Atoms Pub Date : 2023-07-21 DOI: 10.3390/atoms11070106

Bhushan Bhujang, Pragya Das

引用次数: 0

On Invariant Vectors in the Presence of Electric and Magnetic Fields 电场和磁场存在下的不变向量

IF 1.8

Atoms Pub Date : 2023-07-20 DOI: 10.3390/atoms11070105

J. Pain

引用次数: 0

Role of Simple Spatial Gradient in Reinforcing the Accuracy of Temperature Determination of HED Plasma via Spectral Line-Area Ratios 简单空间梯度在提高谱线面积比法测定HED等离子体温度精度中的作用

IF 1.8

Atoms Pub Date : 2023-07-12 DOI: 10.3390/atoms11070104

G. Riggs, M. Koepke, T. Lane, T. Steinberger, P. Kozlowski, I. Golovkin

引用次数: 0

Role of Gas Pressure in Quasi-Phase Matching in High Harmonics Driven by Two-Color Laser Field 气压在双色激光场驱动的高次谐波准相位匹配中的作用

IF 1.8

Atoms Pub Date : 2023-07-07 DOI: 10.3390/atoms11070103

S. Stremoukhov

引用次数: 0

Variational Approaches to Two-Dimensionally Symmetry-Broken Dipolar Bose–Einstein Condensates 二维对称破缺偶极玻色-爱因斯坦凝聚的变分方法

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":" ","pages":""},"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":" ","pages":""},"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

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