Pub Date : 2024-03-04DOI: 10.1088/1361-6455/ad2b6f
J C de Aquino Carvalho, R S N Moreira, J W R Tabosa
We report on the measurements of magnetically assisted dispersion and gain in a Zeeman degenerate two-level system associated with the closed D2 hyperfine transition Fg=3→Fe=2 cold cesium atoms. We use a Mach–Zehnder interferometer to measure the dispersive properties of this system in the presence of a magnetic field, transversal to the quantization direction, when the atomic system is excited by a coupling and probe beams with orthogonal polarizations. We have measured the spectrum of the refraction index for different magnitudes of the external magnetic field and different coupling beam intensities. A previously published theoretical model, using a simpler atomic transition Fg=1→Fe=0, accounts reasonably for the experimentally observed gain and dispersive lineshapes.
{"title":"Measurement of steep dispersion associated with magnetically assisted gain in Zeeman degenerate two-level system of cold atoms","authors":"J C de Aquino Carvalho, R S N Moreira, J W R Tabosa","doi":"10.1088/1361-6455/ad2b6f","DOIUrl":"https://doi.org/10.1088/1361-6455/ad2b6f","url":null,"abstract":"We report on the measurements of magnetically assisted dispersion and gain in a Zeeman degenerate two-level system associated with the closed <italic toggle=\"yes\">D</italic>\u0000<sub>2</sub> hyperfine transition <inline-formula>\u0000<tex-math><?CDATA $F_mathrm{g} = 3 rightarrow F_mathrm{e} = 2$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi>F</mml:mi><mml:mrow><mml:mi mathvariant=\"normal\">g</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>3</mml:mn><mml:mo stretchy=\"false\">→</mml:mo><mml:msub><mml:mi>F</mml:mi><mml:mrow><mml:mi mathvariant=\"normal\">e</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>2</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"bad2b6fieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> cold cesium atoms. We use a Mach–Zehnder interferometer to measure the dispersive properties of this system in the presence of a magnetic field, transversal to the quantization direction, when the atomic system is excited by a coupling and probe beams with orthogonal polarizations. We have measured the spectrum of the refraction index for different magnitudes of the external magnetic field and different coupling beam intensities. A previously published theoretical model, using a simpler atomic transition <inline-formula>\u0000<tex-math><?CDATA $F_mathrm{g} = 1 rightarrow F_mathrm{e} = 0$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mi>F</mml:mi><mml:mrow><mml:mi mathvariant=\"normal\">g</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>1</mml:mn><mml:mo stretchy=\"false\">→</mml:mo><mml:msub><mml:mi>F</mml:mi><mml:mrow><mml:mi mathvariant=\"normal\">e</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>0</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"bad2b6fieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>, accounts reasonably for the experimentally observed gain and dispersive lineshapes.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"62 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316252","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 : 2024-03-04DOI: 10.1088/1361-6455/ad2b72
W Biela-Nowaczyk, F Grilo, P Amaro, A Warczak
We explore the dielectronic recombination structures at the electron beam ion trap at Jagiellonian University in Cracow, emited by cerium that is produced by the high-current cathode made of iridium and cerium. Small amounts of these elements evaporate from the cathode and form low-intensity admixtures within the electron-ion plasma in the EBIT. Their presence and specific ionic population can be observed by examining the spectral characteristics resulting from the DR process. Results have been compared with flexible atomic code calculations, working in unresolved transition array mode, providing identification of the charge states. Here we show that this mode provides quick calculations of very complex data with enough reliability for experimental comparison. These observations highlight which DR features and corresponding charge states that should be present in spectra obtained in EBITs with similar cathode specifications.
我们在克拉科夫雅盖隆大学的电子束离子阱中探索了由铱和铈组成的大电流阴极产生的铈发射的介电子重组结构。少量这些元素从阴极蒸发，在 EBIT 中的电子-离子等离子体中形成低强度混合物。通过检查 DR 过程产生的光谱特征，可以观察到它们的存在和特定的离子群。研究结果与灵活的原子代码计算结果进行了比较，后者以非解析过渡阵列模式工作，提供了电荷状态的识别。我们在此表明，这种模式可以快速计算非常复杂的数据，其可靠性足以用于实验比较。这些观察结果强调了在具有类似阴极规格的 EBIT 中获得的光谱中应该存在的 DR 特征和相应的电荷状态。
{"title":"L-Mn dielectronic recombination of cerium ions in a room-temperature EBIT","authors":"W Biela-Nowaczyk, F Grilo, P Amaro, A Warczak","doi":"10.1088/1361-6455/ad2b72","DOIUrl":"https://doi.org/10.1088/1361-6455/ad2b72","url":null,"abstract":"We explore the dielectronic recombination structures at the electron beam ion trap at Jagiellonian University in Cracow, emited by cerium that is produced by the high-current cathode made of iridium and cerium. Small amounts of these elements evaporate from the cathode and form low-intensity admixtures within the electron-ion plasma in the EBIT. Their presence and specific ionic population can be observed by examining the spectral characteristics resulting from the DR process. Results have been compared with flexible atomic code calculations, working in unresolved transition array mode, providing identification of the charge states. Here we show that this mode provides quick calculations of very complex data with enough reliability for experimental comparison. These observations highlight which DR features and corresponding charge states that should be present in spectra obtained in EBITs with similar cathode specifications.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"63 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316092","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 : 2024-03-04DOI: 10.1088/1361-6455/ad2b73
Balázs Tóth, Attila Tóth, András Csehi
We study the three-photon ionization of atomic lithium by intense, short light pulses, via numerically solving the time-dependent Schrödinger equation. Two-photon Rabi oscillations are induced between the 2s and 4s states, which are damped due to single-photon ionization to the p continuum. Developing a minimal three-level model, we analyze the spectral features of the Autler–Townes (AT) doublet that is formed upon the resonant coupling with the laser pulse. Furthermore, we show that this 2s→→4s→pcontinuum pathway is the dominant process, if the duration of the laser pulse exceeds a certain value. For shorter pulses, ionization through the 2p state (2s→2p→4d→fcontinuum) gradually becomes the dominant process, provided that the pulse is strong enough to induce several Rabi floppings. Here, we trace the competition of these ionization pathways by observing the structural changes in the shape of the AT doublet.
我们通过数值求解随时间变化的薛定谔方程，研究了原子锂在强光短脉冲作用下的三光子电离。在 2s 和 4s 状态之间诱发了双光子拉比振荡，由于单光子电离到 p 连续体，这种振荡被阻尼。我们建立了一个最小三电平模型，分析了与激光脉冲共振耦合后形成的 Autler-Townes (AT) 双态的光谱特征。此外，我们还证明，如果激光脉冲的持续时间超过一定值，这种 2s→→4s→p 连续通路是主要过程。对于较短的脉冲，通过 2p 态（2s→2p→4d→f 连续波）的电离逐渐成为主导过程，前提是脉冲强度足以诱发数次拉比翻转。在这里，我们通过观察 AT 双顶体形状的结构变化来追踪这些电离途径的竞争情况。
{"title":"Competition of multiphoton ionization pathways in lithium","authors":"Balázs Tóth, Attila Tóth, András Csehi","doi":"10.1088/1361-6455/ad2b73","DOIUrl":"https://doi.org/10.1088/1361-6455/ad2b73","url":null,"abstract":"We study the three-photon ionization of atomic lithium by intense, short light pulses, via numerically solving the time-dependent Schrödinger equation. Two-photon Rabi oscillations are induced between the 2<italic toggle=\"yes\">s</italic> and 4<italic toggle=\"yes\">s</italic> states, which are damped due to single-photon ionization to the <italic toggle=\"yes\">p</italic> continuum. Developing a minimal three-level model, we analyze the spectral features of the Autler–Townes (AT) doublet that is formed upon the resonant coupling with the laser pulse. Furthermore, we show that this <inline-formula>\u0000<tex-math><?CDATA $2s rightarrow rightarrow 4s rightarrow p~continuum$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mn>2</mml:mn><mml:mi>s</mml:mi><mml:mo stretchy=\"false\">→→</mml:mo><mml:mn>4</mml:mn><mml:mi>s</mml:mi><mml:mo stretchy=\"false\">→</mml:mo><mml:mi>p</mml:mi><mml:mtext> </mml:mtext><mml:mi>c</mml:mi><mml:mi>o</mml:mi><mml:mi>n</mml:mi><mml:mi>t</mml:mi><mml:mi>i</mml:mi><mml:mi>n</mml:mi><mml:mi>u</mml:mi><mml:mi>u</mml:mi><mml:mi>m</mml:mi></mml:math>\u0000<inline-graphic xlink:href=\"bad2b73ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> pathway is the dominant process, if the duration of the laser pulse exceeds a certain value. For shorter pulses, ionization through the 2<italic toggle=\"yes\">p</italic> state (<inline-formula>\u0000<tex-math><?CDATA $2s rightarrow 2p rightarrow 4d rightarrow f~continuum$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mn>2</mml:mn><mml:mi>s</mml:mi><mml:mo stretchy=\"false\">→</mml:mo><mml:mn>2</mml:mn><mml:mi>p</mml:mi><mml:mo stretchy=\"false\">→</mml:mo><mml:mn>4</mml:mn><mml:mi>d</mml:mi><mml:mo stretchy=\"false\">→</mml:mo><mml:mi>f</mml:mi><mml:mtext> </mml:mtext><mml:mi>c</mml:mi><mml:mi>o</mml:mi><mml:mi>n</mml:mi><mml:mi>t</mml:mi><mml:mi>i</mml:mi><mml:mi>n</mml:mi><mml:mi>u</mml:mi><mml:mi>u</mml:mi><mml:mi>m</mml:mi></mml:math>\u0000<inline-graphic xlink:href=\"bad2b73ieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>) gradually becomes the dominant process, provided that the pulse is strong enough to induce several Rabi floppings. Here, we trace the competition of these ionization pathways by observing the structural changes in the shape of the AT doublet.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"199 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316188","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 : 2024-03-01DOI: 10.1088/1361-6455/ad2b70
Samim Akhtar, Jayanta K Saha, Md Mabud Hossain
We present an azimuthal phase-dependent scheme to study the spatially dependent electromagnetically induced transparency (EIT) and the generation of spatial light in a closed-loop four-level Y-type system. A structured control beam and a microwave (MW) field are adopted in the closed-loop structure. Interestingly, the weak non-vortex probe beam responses explicitly depend on the orbital angular momentum (OAM) of the control beam along with the MW-assisted quantum interference. The regions of spatially dependent EIT are demonstrated at different azimuthal angles. It is found that the intensity of the structured control beam and the relative phase arising out of the beams participating in the closed-loop can be used as the controlling knobs to tailor the shape and the angular location of the spatially dependent EIT.
我们提出了一种与方位角相位相关的方案，用于研究闭环四级 Y 型系统中与空间相关的电磁诱导透明（EIT）和空间光的产生。闭环结构中采用了结构化控制光束和微波（MW）场。有趣的是，微弱的非涡旋探针光束响应明确取决于控制光束的轨道角动量（OAM）以及微波辅助量子干涉。不同方位角的空间依赖性 EIT 区域得到了证实。研究发现，结构化控制光束的强度和参与闭环的光束产生的相对相位可用作控制旋钮，以调整空间相关 EIT 的形状和角度位置。
{"title":"Azimuthal phase-dependent electromagnetically induced transparency and the generation of spatial light in a microwave-assisted four-level Y-type system","authors":"Samim Akhtar, Jayanta K Saha, Md Mabud Hossain","doi":"10.1088/1361-6455/ad2b70","DOIUrl":"https://doi.org/10.1088/1361-6455/ad2b70","url":null,"abstract":"We present an azimuthal phase-dependent scheme to study the spatially dependent electromagnetically induced transparency (EIT) and the generation of spatial light in a closed-loop four-level Y-type system. A structured control beam and a microwave (MW) field are adopted in the closed-loop structure. Interestingly, the weak non-vortex probe beam responses explicitly depend on the orbital angular momentum (OAM) of the control beam along with the MW-assisted quantum interference. The regions of spatially dependent EIT are demonstrated at different azimuthal angles. It is found that the intensity of the structured control beam and the relative phase arising out of the beams participating in the closed-loop can be used as the controlling knobs to tailor the shape and the angular location of the spatially dependent EIT.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"44 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316074","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 : 2024-02-23DOI: 10.1088/1361-6455/ad2861
Fatma Zouari Ahmed, Mohammed Tayeb Meftah, Tommaso Roscilde
Quantum degeneracy is the central many-body feature of ideal quantum gases stemming from quantum mechanics. In this work we address its relationship to the most fundamental form of non-classicality in many-body system, i.e. many-body entanglement. We aim at establishing a quantitative link between quantum degeneracy and entanglement in spinful ideal gases, using entanglement witness criteria based on the variance of the collective spin of the spin ensemble. We show that spin-1/2 ideal Bose gases do not possess entanglement which can be revealed from such entanglement criteria. On the contrary, ideal spin-1/2 Fermi gases exhibit spin entanglement revealed by the collective-spin variances upon entering quantum degeneracy, due to the formation of highly non-local spin singlets. We map out the regime of detectable spin entanglement for Fermi gases in free space as well as in a parabolic trap, and probe the robustness of spin entanglement to thermal effects and spin imbalance. Spin entanglement in degenerate Fermi gases is amenable to experimental observation using state-of-the-art spin detection techniques in ultracold atoms.
{"title":"Quantum degeneracy and spin entanglement in ideal quantum gases","authors":"Fatma Zouari Ahmed, Mohammed Tayeb Meftah, Tommaso Roscilde","doi":"10.1088/1361-6455/ad2861","DOIUrl":"https://doi.org/10.1088/1361-6455/ad2861","url":null,"abstract":"Quantum degeneracy is the central many-body feature of ideal quantum gases stemming from quantum mechanics. In this work we address its relationship to the most fundamental form of non-classicality in many-body system, i.e. many-body entanglement. We aim at establishing a quantitative link between quantum degeneracy and entanglement in spinful ideal gases, using entanglement witness criteria based on the variance of the collective spin of the spin ensemble. We show that spin-1/2 ideal Bose gases do not possess entanglement which can be revealed from such entanglement criteria. On the contrary, ideal spin-1/2 Fermi gases exhibit spin entanglement revealed by the collective-spin variances upon entering quantum degeneracy, due to the formation of highly non-local spin singlets. We map out the regime of detectable spin entanglement for Fermi gases in free space as well as in a parabolic trap, and probe the robustness of spin entanglement to thermal effects and spin imbalance. Spin entanglement in degenerate Fermi gases is amenable to experimental observation using state-of-the-art spin detection techniques in ultracold atoms.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"45 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140006055","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 : 2024-02-23DOI: 10.1088/1361-6455/ad23f7
Liping Zou, Pengming Zhang, Alexander J Silenko
The use of a (quasi)uniform magnetic field opens new possibilities for the production of twisted particles having orbital angular momenta. We ascertain these possibilities. Quantum states suitable for the creation of charged particles in a uniform magnetic field are determined. The particle penetration from a solenoid to vacuum or another solenoid is analyzed in detail. It is shown that a previously proposed approach can be utilized for the successful production of twisted positrons and positroniums. We also find a new effect of increasing the uncertainty of the phase of the particle rotation with the distance passed by the particle in the solenoid. This effect, based on the fundamentals of quantum mechanics, leads to exciting new possibilities for the production of twisted particles in real solenoids without additional particle sources therein.
{"title":"Production of twisted particles in magnetic fields","authors":"Liping Zou, Pengming Zhang, Alexander J Silenko","doi":"10.1088/1361-6455/ad23f7","DOIUrl":"https://doi.org/10.1088/1361-6455/ad23f7","url":null,"abstract":"The use of a (quasi)uniform magnetic field opens new possibilities for the production of twisted particles having orbital angular momenta. We ascertain these possibilities. Quantum states suitable for the creation of charged particles in a uniform magnetic field are determined. The particle penetration from a solenoid to vacuum or another solenoid is analyzed in detail. It is shown that a previously proposed approach can be utilized for the successful production of twisted positrons and positroniums. We also find a new effect of increasing the uncertainty of the phase of the particle rotation with the distance passed by the particle in the solenoid. This effect, based on the fundamentals of quantum mechanics, leads to exciting new possibilities for the production of twisted particles in real solenoids without additional particle sources therein.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"79 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140006081","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}
In our recent paper (Gangwar et al 2023 J. Phys. B: At. Mol. Opt. Phys.56 165302), we noticed a minor mistake in equations (1) and (2). In this corrigendum, we provide the corrected equations and necessary modified figures. However, overall results and conclusions of our original paper remain unchanged.
在我们最近的论文（Gangwar et al 2023 J. Phys. B: At. Mol. Opt. Phys.56 165302）中，我们注意到方程 (1) 和 (2) 中的一个小错误。在本更正中，我们提供了更正后的方程和必要的修改图。但是，原论文的总体结果和结论保持不变。
{"title":"Corrigendum: Exploring the role of beyond mean-field interaction in the structure and dynamics of one-dimensional quantum droplets (2023 J. Phys. B: At. Mol. Opt. Phys. 56 165302)","authors":"Sonali Gangwar, Rajamanickam Ravisankar, Paulsamy Muruganandam, Pankaj Kumar Mishra","doi":"10.1088/1361-6455/ad2549","DOIUrl":"https://doi.org/10.1088/1361-6455/ad2549","url":null,"abstract":"In our recent paper (Gangwar <italic toggle=\"yes\">et al</italic> 2023 <italic toggle=\"yes\">J. Phys. B: At. Mol. Opt. Phys.</italic>\u0000<bold>56</bold> 165302), we noticed a minor mistake in equations (1) and (2). In this corrigendum, we provide the corrected equations and necessary modified figures. However, overall results and conclusions of our original paper remain unchanged.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"79 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140006064","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 : 2024-02-21DOI: 10.1088/1361-6455/ad285c
Alba Jorge, Marko Horbatsch, Tom Kirchner
We use an independent electron model with semi-classical approximation to electron dynamics to investigate differential cross sections for electron emission in fast collisions of protons with ammonia molecules. An effective potential model for the electronic orbitals is introduced, and utilized in the context of the classical-trajectory Monte Carlo (CTMC) approach for single-electron dynamics. Cross sections differential in electron emission angle and energy are compared with experimental data. Compared to previous scattering-theory based quantum-mechanical results the time-dependent semi-classical CTMC approach provides results of similar quality for intermediate and high ionized electron energies. We find some discrepancies in the total cross sections for q-fold ionization between the present model and independent-atom-model calculations. The double ionization cross sections are considerably larger than recent experimental data which are derived from coincidence counting of charged fragments. The calculated triple ionization cross sections exceed the experimental coincidence data for q = 3 by several orders of magnitude at intermediate energies.
{"title":"Classical-trajectory model for ionizing proton-ammonia molecule collisions: the role of multiple ionization","authors":"Alba Jorge, Marko Horbatsch, Tom Kirchner","doi":"10.1088/1361-6455/ad285c","DOIUrl":"https://doi.org/10.1088/1361-6455/ad285c","url":null,"abstract":"We use an independent electron model with semi-classical approximation to electron dynamics to investigate differential cross sections for electron emission in fast collisions of protons with ammonia molecules. An effective potential model for the electronic orbitals is introduced, and utilized in the context of the classical-trajectory Monte Carlo (CTMC) approach for single-electron dynamics. Cross sections differential in electron emission angle and energy are compared with experimental data. Compared to previous scattering-theory based quantum-mechanical results the time-dependent semi-classical CTMC approach provides results of similar quality for intermediate and high ionized electron energies. We find some discrepancies in the total cross sections for <italic toggle=\"yes\">q</italic>-fold ionization between the present model and independent-atom-model calculations. The double ionization cross sections are considerably larger than recent experimental data which are derived from coincidence counting of charged fragments. The calculated triple ionization cross sections exceed the experimental coincidence data for <italic toggle=\"yes\">q</italic> = 3 by several orders of magnitude at intermediate energies.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"45 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140005851","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 : 2024-02-12DOI: 10.1088/1361-6455/ad23f6
S Kim, S Steinhäuser, A B Voitkiv, C Müller
Ionization-excitation of an atom induced by the absorption of a single photon in the presence of a neighboring atom is studied. The latter is, first, resonantly photoexcited and, afterwards, transfers the excitation energy radiationlessly to the other atom, leading to its ionization with simultaneous excitation. The process relies on the combined effects of interatomic and intraatomic electron correlations. Under suitable conditions, it can dominate by several orders of magnitude over direct photoionization-excitation and even over direct photoionization. In addition, we briefly discuss another kind of two-center resonant photoionization with excitation where the ionization and residual excitation in the final state are located at different atomic sites.
{"title":"Two-center resonant photoionization-excitation driven by combined intra- and interatomic electron correlations","authors":"S Kim, S Steinhäuser, A B Voitkiv, C Müller","doi":"10.1088/1361-6455/ad23f6","DOIUrl":"https://doi.org/10.1088/1361-6455/ad23f6","url":null,"abstract":"Ionization-excitation of an atom induced by the absorption of a single photon in the presence of a neighboring atom is studied. The latter is, first, resonantly photoexcited and, afterwards, transfers the excitation energy radiationlessly to the other atom, leading to its ionization with simultaneous excitation. The process relies on the combined effects of interatomic and intraatomic electron correlations. Under suitable conditions, it can dominate by several orders of magnitude over direct photoionization-excitation and even over direct photoionization. In addition, we briefly discuss another kind of two-center resonant photoionization with excitation where the ionization and residual excitation in the final state are located at different atomic sites.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"308 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769993","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 : 2024-02-12DOI: 10.1088/1361-6455/ad2546
Jakub Kopyciński, Buğra Tüzemen, Wojciech Górecki, Krzysztof Pawłowski, Maciej Łebek
We investigate dark solitons in two-component Bose systems with competing interactions in one dimension. Such a system hosts a liquid phase stabilized by the beyond-mean field corrections. Using the generalized Gross–Pitaevskii equation, we reveal the presence of two families of solitonic solutions. The solitons in both of them can be engineered to be arbitrarily wide. One family of solutions, however, has an anomalous dispersion relation, and our analyses show one of its branches is unstable. We find a critical velocity that demarcates the stable from unstable solutions. Nonetheless, gray anomalous solitons can exist inside quantum droplets and can be treated as solitonic excitations thereof.
{"title":"Propagation properties and stability of dark solitons in weakly interacting Bose–Bose droplets","authors":"Jakub Kopyciński, Buğra Tüzemen, Wojciech Górecki, Krzysztof Pawłowski, Maciej Łebek","doi":"10.1088/1361-6455/ad2546","DOIUrl":"https://doi.org/10.1088/1361-6455/ad2546","url":null,"abstract":"We investigate dark solitons in two-component Bose systems with competing interactions in one dimension. Such a system hosts a liquid phase stabilized by the beyond-mean field corrections. Using the generalized Gross–Pitaevskii equation, we reveal the presence of two families of solitonic solutions. The solitons in both of them can be engineered to be arbitrarily wide. One family of solutions, however, has an anomalous dispersion relation, and our analyses show one of its branches is unstable. We find a critical velocity that demarcates the stable from unstable solutions. Nonetheless, gray anomalous solitons can exist inside quantum droplets and can be treated as solitonic excitations thereof.","PeriodicalId":16826,"journal":{"name":"Journal of Physics B: Atomic, Molecular and Optical Physics","volume":"5 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769999","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}
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