Journal of Physics B: Atomic, Molecular and Optical Physics最新文献

{"title":"Addendum: Multichannel quantum defect theory of strontium bound Rydberg states (2014 J. Phys. B: At. Mol. Opt. Phys. 47 155001)","authors":"C L Vaillant, M P A Jones and R M Potvliege","doi":"10.1088/1361-6455/ad76f0","DOIUrl":"https://doi.org/10.1088/1361-6455/ad76f0","url":null,"abstract":"Newly calculated multichannel quantum defect theory parameters and channel fractions are presented for the singlet and triplet S, P and D series and singlet F series of strontium. These results correct those reported in Vaillant et al (2014 J. Phys. B: At. Mol. Opt. Phys.47 155001).","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laser-assisted radiative recombination in a cold hydrogen plasma","authors":"I I Fabrikant and H B Ambalampitiya","doi":"10.1088/1361-6455/ad75f6","DOIUrl":"https://doi.org/10.1088/1361-6455/ad75f6","url":null,"abstract":"We study the process of laser-assisted radiative recombination of an electron with a proton in a cold hydrogen plasma employing the semiclassical Kramers’ approach which involves calculation of classical trajectories in combined laser and Coulomb fields and the use of the correspondence principle. Due to the Coulomb focusing effect, recombination is the most effective when the initial electron momentum is parallel to the laser polarization. Orders of magnitude enhancement of the cross section, as compared to the laser-free case, is observed in this case. With increasing angle between the electron momentum and polarization, the recombination cross section drops. However, even after averaging over Maxwellian velocity distribution we obtain a substantial enhancement of the recombination rate constant, as compared to the zero-field case. For the field intensities in the range 30–350 MW cm−2, the enhancement occurs in the region of the radiation wavelength from 5 to 20 µm and for the plasma temperature from 20 to 300 K.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Absolute nuclear charge radius by Na-like spectral line separation in high-Z elements","authors":"A Hosier, 0000-0001-6675-8509Dipti3, S A Blundell, R Silwal, A Lapierre, J D Gillaspy, G Gwinner, J N Tan, A A Kwiatkowski, Y Wang, H Staiger, A C C Villari, Yu Ralchenko, E Takacs","doi":"10.1088/1361-6455/ad717b","DOIUrl":"https://doi.org/10.1088/1361-6455/ad717b","url":null,"abstract":"We describe a novel technique to determine absolute nuclear radii of high-<italic toggle=\"yes\">Z</italic> nuclides. Utilizing accurate theoretical atomic structure calculations together with precise measurements of extreme ultraviolet transitions in highly charged ions this method allows for precise determinations of absolute nuclear charge radii based upon the well-known nuclear radii of their neighboring elements. This method can work for elements without stable isotopes, and its accuracy may be competitive with current methods (electron scattering and muonic x-ray spectroscopy).","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perspective for in-volume machining of solid materials by undersurface focusing of x-ray pulses","authors":"Ichiro Inoue, Beata Ziaja","doi":"10.1088/1361-6455/ad7551","DOIUrl":"https://doi.org/10.1088/1361-6455/ad7551","url":null,"abstract":"In this perspective article we propose and discuss a possible technique of in-depth material processing based on undersurface focusing of intense x-ray pulses. Currently, x-ray free-electron lasers can produce such intense x-ray pulses with femtosecond pulse durations, reaching intensities sufficiently high to cause ultrafast melting of a material after a single laser shot. Here, on the example of silicon crystal we will demonstrate that with a proper choice of pulse parameters and focusing parameters, the already existing nanofocusing setup has a capability to focus hard x rays down to several hundreds micrometers below the material surface. This can trigger the required structural modification in the focal point, without damaging the material above. Potential applications of the new technique are discussed.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracking dissociation pathways of nitrobenzene via mega-electron-volt ultrafast electron diffraction","authors":"Kareem Hegazy, Phil Bucksbaum, Martin Centurion, James Cryan, Renkai Li, Ming-Fu Lin, Bryan Moore, Pedro Nunes, Xiaozhe Shen, Stephen Weathersby, Jie Yang, Xijie Wang, Thomas Wolf","doi":"10.1088/1361-6455/ad7431","DOIUrl":"https://doi.org/10.1088/1361-6455/ad7431","url":null,"abstract":"As the simplest nitroaromatic compound, nitrobenzene is an interesting model system to explore the rich photochemistry of nitroaromatic compounds. Previous investigations of nitrobenzene’s photochemical dynamics have probed structural and electronic properties. These investigations paint, at times, a convoluted and sometimes contradictory description of the photochemical landscape. We investigate the ultrafast dynamics of nitrobenzene triggered by photoexcitation at 267 nm for the first time using a structural probe with femtosecond time resolution. Our probe complements previous measurements of nitrobenzene’s electronic structure evolution and aids in determining the photochemical dynamics with less ambiguity. We employ megaelectronvolt ultrafast electron diffraction to follow nitrobenzene’s structural evolution within the first 5 ps after photoexcitation. We observe ground state recovery within <inline-formula>\u0000<tex-math><?CDATA $160 pm 60$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:mn>160</mml:mn><mml:mo>±</mml:mo><mml:mn>60</mml:mn></mml:mrow></mml:math><inline-graphic xlink:href=\"bad7431ieqn1.gif\"></inline-graphic></inline-formula> fs through nonadiabatic dynamics. Based on comparisons of the experimental signal with molecular dynamics simulations, we exclude a significant population of the triplet manifold. Furthermore, we do not observe fragmentation of nitrobenzene within the investigated time window, which indicates that previously observed photofragmentation reactions take place in the vibrationally ‘hot’ ground state on timescales considerably beyond 5 ps.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atom number fluctuations in Bose gases—statistical analysis of parameter estimation","authors":"T Vibel, M B Christensen, R M F Andersen, L N Stokholm, K Pawłowski, K Rzążewski, M A Kristensen, J J Arlt","doi":"10.1088/1361-6455/ad7458","DOIUrl":"https://doi.org/10.1088/1361-6455/ad7458","url":null,"abstract":"The investigation of atom number fluctuations in quantum gases at finite temperatures showcases the ongoing challenges in understanding complex quantum systems. Recently, the microcanonical nature of atom number fluctuations in weakly interacting Bose–Einstein condensates was observed. This motivates an investigation of the thermal component of partially condensed Bose gases, due to the conservation of the total atom number. Here, we present a combined analysis of both components, including a comprehensive analysis of the uncertainties in the preparation and parameter extraction of partially condensed quantum gases. This enables a complementary observation of the thermal atom number fluctuations and yields and improved value of the peak BEC atom number fluctuations <inline-formula>\u0000<tex-math><?CDATA $Delta N_mathrm{p,0}^2 = (3.7pm7)times10^5$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:mi mathvariant=\"normal\">Δ</mml:mi><mml:msubsup><mml:mi>N</mml:mi><mml:mrow><mml:mi mathvariant=\"normal\">p</mml:mi><mml:mo>,</mml:mo><mml:mn>0</mml:mn></mml:mrow><mml:mn>2</mml:mn></mml:msubsup><mml:mo>=</mml:mo><mml:mo stretchy=\"false\">(</mml:mo><mml:mn>3.7</mml:mn><mml:mo>±</mml:mo><mml:mn>7</mml:mn><mml:mo stretchy=\"false\">)</mml:mo><mml:mo>×</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mn>5</mml:mn></mml:msup></mml:mrow></mml:math><inline-graphic xlink:href=\"bad7458ieqn1.gif\"></inline-graphic></inline-formula> close to the critical temperature. This corresponds to a reduction by 41% with respect to previous analysis and corroborates the microcanonical nature of the fluctuations. The analysis of noise contributions due to the preparation and evaluation of partially condensed Bose gases is based on Monte Carlo simulations of optical density profiles. Importantly, this allows for an estimation of the technical noise contributions to the atom number and temperature, which is generally applicable in the field of ultracold atoms.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anisotropy-driven magnetic phase transitions in SU(4)-symmetric Fermi gas in three-dimensional optical lattices","authors":"Vladyslav Unukovych, Andrii Sotnikov","doi":"10.1088/1361-6455/ad6b63","DOIUrl":"https://doi.org/10.1088/1361-6455/ad6b63","url":null,"abstract":"We study an SU(4)-symmetric ultracold fermionic mixture in a cubic optical lattice with a variable tunneling amplitude along one particular crystallographic axis in the crossover region from the two- to three-dimensional spatial geometry. To theoretically analyze the emerging magnetic phases and physical observables, we describe the system within the framework of the Fermi–Hubbard model and apply dynamical mean-field theory. We show that in two limiting cases of anisotropy, there are two phases with different antiferromagnetic orderings in the zero temperature limit and we determine a region of their coexistence. We also study the stability regions of different magnetically ordered states and density profiles of the gas in the harmonic optical trap.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Entanglement of a three-level atom interacting with two-modes field in a cavity","authors":"A del Rio-Lima, F J Poveda-Cuevas, O Castaños","doi":"10.1088/1361-6455/ad717d","DOIUrl":"https://doi.org/10.1088/1361-6455/ad717d","url":null,"abstract":"The dynamics of an atom of three levels in Λ configuration interacting with a quantized field of two modes in a cavity is studied within the rotating wave approximation by considering experimental values of accessible hyperfine levels of alkali atoms. The Hamiltonian model is constructed on the basis of the direct product of the atomic states with Fock states of light. This simplified basis allows us to generalize the state of light to any quantum field. The interaction term of the Hamiltonian restricts the system to a 3D Hilbert space. The system’s time evolution results show some similarities with the effective two-level system, such as the presence of collapses and revivals and the atom-field entanglement. By an analysis of the statistics of the photons, we show that when the three-level atom is interacting with a coherent field of two modes, it is possible to control experimentally the statistics of the field to be super-Poissonian or sub-Poissonian by the choice of the initial atomic state.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polarization spectroscopy of 87Rb-D2 line using structured light: controlling the line shape of closed hyperfine transition","authors":"Samim Akhtar, Aparajita Das, Md Mabud Hossain","doi":"10.1088/1361-6455/ad717c","DOIUrl":"https://doi.org/10.1088/1361-6455/ad717c","url":null,"abstract":"In this article, we present the influence of structured light on the line shape of closed hyperfine transition <inline-formula>\u0000<tex-math><?CDATA $F = 2 rightarrow F^{^{prime}} = 3$?></tex-math><mml:math overflow=\"scroll\"><mml:mrow><mml:mi>F</mml:mi><mml:mo>=</mml:mo><mml:mn>2</mml:mn><mml:mo stretchy=\"false\">→</mml:mo><mml:msup><mml:mi>F</mml:mi><mml:mrow><mml:mi>′</mml:mi></mml:mrow></mml:msup><mml:mo>=</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:math><inline-graphic xlink:href=\"bad717cieqn1.gif\"></inline-graphic></inline-formula> of ⁸⁷Rb-D₂ line by monitoring the linearly polarized probe Gaussian beam in the presence of circularly polarized pump Laguerre–Gaussian (LG) beam having different orders of orbital angular momentum (OAM). It is observed that both the amplitude and line-width of the closed hyperfine signal under polarization spectroscopy (PS) are enhanced (reduced) with the increasing values of the pump light ellipticity for the non-zero-order (zero-order) OAM. Furthermore, the dispersion-like PS signal of the closed hyperfine transition is modified by varying the pump power and angular mismatch of the pump-probe beams. The experimental results demonstrate that the anisotropy of an atomic medium can be influenced by the OAM of light and can be further modulated by tuning the ellipticity of the structured light.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protocols for x-ray transient grating pump/optical probe experiments at x-ray free electron lasers","authors":"Danny Fainozzi, Riccardo Cucini, Joan Vila-Comamala, Frederico Lima, Fernando Ardana-Lamas, Luis Bañares, Matias Bargheer, Filippo Bencivenga, Nadia Berndt, Martin Beye, Mykola Biednov, Stefano Bonetti, Marta Brioschi, Andrea Cannizzo, Pietro Carrara, Majed Chergui, Christian David, Robin Y Engel, Eugenio Ferrari, Thomas Feurer, Paul Frankenberger, Wojciech M Gawelda, Alessandro Gessini, Siti Heder, Xinchao Huang, Nupur N Khatu, Martin Knoll, Anders Madsen, Talgat Mamyrbayev, Claudio Masciovecchio, Alexei A Maznev, Christopher Milne, Riccardo Mincigrucci, Keith A Nelson, Ettore Paltanin, Giorgio Rossi, Markus Scholz, Carles Serrat, Urs Staub, Jakub Szlachetko, Renato Torre, Mano R Dhanalakshmi-Veeraraj, Han Xu, Peter Zalden, Cristian Svetina","doi":"10.1088/1361-6455/ad717f","DOIUrl":"https://doi.org/10.1088/1361-6455/ad717f","url":null,"abstract":"Transient grating spectroscopy is a specialized application of the four-wave-mixing methodology and constitutes a versatile technique for investigating the dynamics of vibrational, magnetic and electronic degrees of freedom of matter in a background-free fashion. Recent developments in free-electron laser sources have enabled the extension of this technique into the extreme ultraviolet range. Ongoing efforts to expand transient grating spectroscopy into the x-ray regime promise numerous advantages: (1) substantial penetration depths that allow for probing bulk material properties, (2) element specificity via specific core-excited states, and (3) short wavelengths that allow for excitation gratings with higher momentum transfer and improved spatial resolution. In this study, we comprehensively outline the procedures for conducting x-ray transient grating pump/optical probe experiment. The process encompasses the design and alignment of the experimental setup, as well as the subsequent steps involved in data acquisition and analysis. This paper is intended as a comprehensive guide for researchers interested in implementing x-ray transient grating spectroscopy, providing valuable insights into the intricacies of the experimental workflow required for this novel technique. Furthermore, we discuss the potential for extending this methodology to an x-ray pump/x-ray probe scheme, envisioning a future direction that holds promise for enhancing the capabilities and scope of x-ray transient grating spectroscopy, opening new opportunities for studying ultrafast processes with unprecedented temporal and spatial resolutions.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}