Pub Date : 2024-06-25DOI: 10.1088/1361-6455/ad5893
D V Rezvan, A Pier, S Grundmann, N M Novikovskiy, N Anders, M Kircher, N Melzer, F Trinter, M S Schöffler, T Jahnke, R Dörner and Ph V Demekhin
We investigate experimentally and theoretically the N 1s photoionization of fixed-in-space N2 molecules at a photon energy of 880 eV. In our experiment, we employed circularly polarized synchrotron radiation for the photoionization and coincident electron and fragment-ion detection using cold target recoil ion momentum spectroscopy. The accompanying angle-resolved calculations were carried out by the multichannel single-center method and code within the frozen-core Hartree–Fock approximation. The computed emission distributions exhibit two distinct features along the molecular axis, which are the results of a superposition of the direct and nearest-neighbor scattering amplitudes for the photoemission from two nitrogen atoms. In the electric-dipole approximation, these peaks are symmetric with respect to both nitrogen atoms. Including nondipole (retardation) effects in the calculations results in a simultaneous increase and decrease of the scattering peaks towards the nitrogen atoms pointing in the forward and backward directions along the light propagation, respectively. These theoretical findings are in agreement with our experimental findings.
我们从实验和理论上研究了光子能量为 880 eV 时固定在空间中的 N2 分子的 N 1s 光离子化。在实验中,我们采用了圆偏振同步辐射进行光离子化,并利用冷靶反冲离子动量谱进行了电子和碎片离子的同步探测。伴随的角度分辨计算是通过多通道单中心方法和冷冻核心哈特里-福克近似代码进行的。计算得出的发射分布沿分子轴线呈现出两个明显的特征,这是两个氮原子光发射的直接散射和近邻散射振幅叠加的结果。在电偶极子近似中,这些峰值相对于两个氮原子是对称的。将非偶极子(延迟)效应纳入计算会导致散射峰同时增大和减小,分别指向沿光传播的前向和后向的氮原子。这些理论结果与我们的实验结果一致。
{"title":"Nondipolar photoelectron angular distributions from fixed-in-space N2 molecules","authors":"D V Rezvan, A Pier, S Grundmann, N M Novikovskiy, N Anders, M Kircher, N Melzer, F Trinter, M S Schöffler, T Jahnke, R Dörner and Ph V Demekhin","doi":"10.1088/1361-6455/ad5893","DOIUrl":"https://doi.org/10.1088/1361-6455/ad5893","url":null,"abstract":"We investigate experimentally and theoretically the N 1s photoionization of fixed-in-space N2 molecules at a photon energy of 880 eV. In our experiment, we employed circularly polarized synchrotron radiation for the photoionization and coincident electron and fragment-ion detection using cold target recoil ion momentum spectroscopy. The accompanying angle-resolved calculations were carried out by the multichannel single-center method and code within the frozen-core Hartree–Fock approximation. The computed emission distributions exhibit two distinct features along the molecular axis, which are the results of a superposition of the direct and nearest-neighbor scattering amplitudes for the photoemission from two nitrogen atoms. In the electric-dipole approximation, these peaks are symmetric with respect to both nitrogen atoms. Including nondipole (retardation) effects in the calculations results in a simultaneous increase and decrease of the scattering peaks towards the nitrogen atoms pointing in the forward and backward directions along the light propagation, respectively. These theoretical findings are in agreement with our experimental findings.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"33 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512343","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}
Pub Date : 2024-06-25DOI: 10.1088/1361-6455/ad5895
Ling-Zheng Meng, Li-Chen Zhao, Thomas Busch and Yongping Zhang
While usually the optical diffraction limit is setting a limit for the lengthscales on which a typical alkali Bose–Einstein condensate can be controlled, we show that in certain situations control via matter waves can achieve smaller resolutions. For this we consider a small number of impurity atoms which are trapped inside the density dip of a dark soliton state and show that any grey soliton state can be obtained by selectively driving the impurity atoms. This allows to fully control the position and velocity of the dark soliton, and also study controlled collisions between these non-linear objects.
{"title":"Controlling dark solitons on the healing length scale","authors":"Ling-Zheng Meng, Li-Chen Zhao, Thomas Busch and Yongping Zhang","doi":"10.1088/1361-6455/ad5895","DOIUrl":"https://doi.org/10.1088/1361-6455/ad5895","url":null,"abstract":"While usually the optical diffraction limit is setting a limit for the lengthscales on which a typical alkali Bose–Einstein condensate can be controlled, we show that in certain situations control via matter waves can achieve smaller resolutions. For this we consider a small number of impurity atoms which are trapped inside the density dip of a dark soliton state and show that any grey soliton state can be obtained by selectively driving the impurity atoms. This allows to fully control the position and velocity of the dark soliton, and also study controlled collisions between these non-linear objects.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"23 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512344","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}
Pub Date : 2024-06-16DOI: 10.1088/1361-6455/ad3ff4
G Baskaran and A R May
The year 2024 marks the 100th anniversary of the first article on Bose statistics. Bose breathed life into the Planck distribution of radiation by a microscopic derivation (Bose 1924 Z. Phys.26 178), adding a new insight, namely indistinguishability into the then evolving quantum theory. Einstein recognized the importance of this article and got it published. Using Bose statistics Einstein wrote an article on the theory (Einstein 1924 Sutzungsber. Preuss. Akad. Wiss Phys.-Math Kl. 261) of an ideal Bose gas and Bose–Einstein condensation. The groundbreaking discovery of Bose, an unveiling of a secret of quantum mechanics, continues to reverberate after a century. Bose’s paper is considered the fourth important paper in old quantum theory, following Planck’s (1900) article (Planck 1900 Verh. Disch Phys. Ges.2 202), Einstein’s (1905) photoelectric effect (Einstein 1905 Ann. Phys., Lpz.17 132) and Bohr’s model (1913) of the atom (Bohr 1913 London, Edinburgh Dublin Phil. Mag. J. Sci.26 1). Dirac (1926 Proc. R. Soc. A 112 661) coined the name boson for one of the two families of indistinguishable particles, the other family being fermion. The edifice of modern quantum field theory, many-body quantum theory, quantum-information and quantum-computing are built on bosons, fermions and anyons. The ever-blooming quantum garden of bosons has photons, gluons, W-bosons, mesons, Higgs-bosons, gravitons, phonons, magnons, excitons, plasmons, polaritons and so on. We present a brief historical account of Bose’s life and his discovery, followed by a bird’s eye view of the impacts of bosons in modern science and technology: from Bose’s distribution of 3-degree background radiation reaching us in the form of cosmic microwave background from the big bang era to boson sampling, a novel quantum computing method. Bosogenesis before Baryogenesis?: And God said, Let there be light: and there was light (Genesis, 1:4)
{"title":"Boson bloom","authors":"G Baskaran and A R May","doi":"10.1088/1361-6455/ad3ff4","DOIUrl":"https://doi.org/10.1088/1361-6455/ad3ff4","url":null,"abstract":"The year 2024 marks the 100th anniversary of the first article on Bose statistics. Bose breathed life into the Planck distribution of radiation by a microscopic derivation (Bose 1924 Z. Phys.26 178), adding a new insight, namely indistinguishability into the then evolving quantum theory. Einstein recognized the importance of this article and got it published. Using Bose statistics Einstein wrote an article on the theory (Einstein 1924 Sutzungsber. Preuss. Akad. Wiss Phys.-Math Kl. 261) of an ideal Bose gas and Bose–Einstein condensation. The groundbreaking discovery of Bose, an unveiling of a secret of quantum mechanics, continues to reverberate after a century. Bose’s paper is considered the fourth important paper in old quantum theory, following Planck’s (1900) article (Planck 1900 Verh. Disch Phys. Ges.2 202), Einstein’s (1905) photoelectric effect (Einstein 1905 Ann. Phys., Lpz.17 132) and Bohr’s model (1913) of the atom (Bohr 1913 London, Edinburgh Dublin Phil. Mag. J. Sci.26 1). Dirac (1926 Proc. R. Soc. A 112 661) coined the name boson for one of the two families of indistinguishable particles, the other family being fermion. The edifice of modern quantum field theory, many-body quantum theory, quantum-information and quantum-computing are built on bosons, fermions and anyons. The ever-blooming quantum garden of bosons has photons, gluons, W-bosons, mesons, Higgs-bosons, gravitons, phonons, magnons, excitons, plasmons, polaritons and so on. We present a brief historical account of Bose’s life and his discovery, followed by a bird’s eye view of the impacts of bosons in modern science and technology: from Bose’s distribution of 3-degree background radiation reaching us in the form of cosmic microwave background from the big bang era to boson sampling, a novel quantum computing method. Bosogenesis before Baryogenesis?: And God said, Let there be light: and there was light (Genesis, 1:4)","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"24 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505624","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}
Pub Date : 2024-06-13DOI: 10.1088/1361-6455/ad53ae
T Vibel, M B Christensen, M A Kristensen, J J Thuesen, L N Stokholm, C A Weidner and J J Arlt
The accurate determination of atom numbers is an ubiquitous problem in the field of ultracold atoms. For modest atom numbers, absolute calibration techniques are available, however, for large numbers and high densities, the available techniques neglect many-body scattering processes. Here, a spatial calibration technique for time-of-flight absorption images of ultracold atomic clouds is presented. The calibration is obtained from radially averaged absorption images and we provide a practical guide to the calibration process. It is shown that the calibration coefficient scales linearly with optical density and depends on the absorbed photon number for the experimental conditions explored here. This allows for the direct inclusion of a spatially dependent calibration in the image analysis. For typical ultracold atom clouds the spatial calibration technique leads to corrections in the detected atom number up to and temperature up to in comparison to previous calibration techniques. The technique presented here addresses a major difficulty in absorption imaging of ultracold atomic clouds and prompts further theoretical work to understand the scattering processes in ultracold dense clouds of atoms for accurate atom number calibration.
{"title":"Spatial calibration of high-density absorption imaging","authors":"T Vibel, M B Christensen, M A Kristensen, J J Thuesen, L N Stokholm, C A Weidner and J J Arlt","doi":"10.1088/1361-6455/ad53ae","DOIUrl":"https://doi.org/10.1088/1361-6455/ad53ae","url":null,"abstract":"The accurate determination of atom numbers is an ubiquitous problem in the field of ultracold atoms. For modest atom numbers, absolute calibration techniques are available, however, for large numbers and high densities, the available techniques neglect many-body scattering processes. Here, a spatial calibration technique for time-of-flight absorption images of ultracold atomic clouds is presented. The calibration is obtained from radially averaged absorption images and we provide a practical guide to the calibration process. It is shown that the calibration coefficient scales linearly with optical density and depends on the absorbed photon number for the experimental conditions explored here. This allows for the direct inclusion of a spatially dependent calibration in the image analysis. For typical ultracold atom clouds the spatial calibration technique leads to corrections in the detected atom number up to and temperature up to in comparison to previous calibration techniques. The technique presented here addresses a major difficulty in absorption imaging of ultracold atomic clouds and prompts further theoretical work to understand the scattering processes in ultracold dense clouds of atoms for accurate atom number calibration.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"186 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512345","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}
Pub Date : 2024-06-07DOI: 10.1088/1361-6455/ad4fd2
Cai-Yun Zhao, Hui-Li Han, Ting-Yun Shi
We investigate the effects of p-wave interactions on Efimov trimers in systems comprising two identical heavy fermions and a light particle, with mass ratios larger than 13.6. Our focus lies on the Borromean regime where the ground-state trimer exists in the absence of dimers. Using pair-wise Lennard–Jones potentials and concentrating on the