Pub Date : 2020-08-16DOI: 10.1103/physreva.102.053113
Kai Li, M. Labeye, P. Ho, M. Gaarde, L. Young
We present a theoretical study of temporal, spectral, and spatial reshaping of intense, ultrafast x-ray pulses propagating through a resonant medium. Our calculations are based on the solution of a 3D time-dependent Schrodinger-Maxwell equation, with the incident x-ray photon energy on resonance with the core-level 1s-3p transition in neon. We study the evolution of the combined incident and medium-generated field, including the effects of stimulated emission, absorption, ionization and Auger decay, as a function of the input pulse energy and duration. We find that stimulated Raman scattering between core-excited states $1s^{-1}3p$ and $2p^{-1}3p$ occurs at high x-ray intensity, and that the emission around this frequency is strongly enhanced when also including the similar $1s^{-1}-2p^{-1}$ response of the ion. We also explore the dependence of x-ray self-induced transparency (SIT) and self-focusing on the pulse intensity and duration, and we find that the stimulated Raman scattering plays an important role in both effects. Finally, we discuss how these nonlinear effects may potentially be exploited as control parameters for pulse properties of x-ray free-electron laser sources.
{"title":"Resonant propagation of x rays from the linear to the nonlinear regime","authors":"Kai Li, M. Labeye, P. Ho, M. Gaarde, L. Young","doi":"10.1103/physreva.102.053113","DOIUrl":"https://doi.org/10.1103/physreva.102.053113","url":null,"abstract":"We present a theoretical study of temporal, spectral, and spatial reshaping of intense, ultrafast x-ray pulses propagating through a resonant medium. Our calculations are based on the solution of a 3D time-dependent Schrodinger-Maxwell equation, with the incident x-ray photon energy on resonance with the core-level 1s-3p transition in neon. We study the evolution of the combined incident and medium-generated field, including the effects of stimulated emission, absorption, ionization and Auger decay, as a function of the input pulse energy and duration. We find that stimulated Raman scattering between core-excited states $1s^{-1}3p$ and $2p^{-1}3p$ occurs at high x-ray intensity, and that the emission around this frequency is strongly enhanced when also including the similar $1s^{-1}-2p^{-1}$ response of the ion. We also explore the dependence of x-ray self-induced transparency (SIT) and self-focusing on the pulse intensity and duration, and we find that the stimulated Raman scattering plays an important role in both effects. Finally, we discuss how these nonlinear effects may potentially be exploited as control parameters for pulse properties of x-ray free-electron laser sources.","PeriodicalId":8441,"journal":{"name":"arXiv: Atomic Physics","volume":"142 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77808804","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}
Pub Date : 2020-08-14DOI: 10.1103/physreva.102.053327
Scott Eustice, K. Cassella, D. Stamper-Kurn
We propose the application of laser cooling to a number of transition-metal atoms, allowing numerous bosonic and fermionic atomic gases to be cooled to ultra-low temperatures. The non-zero electron orbital angular momentum of these atoms implies that strongly atom-state-dependent light-atom interactions occur even for light that is far-detuned from atomic transitions. At the same time, many transition-metal atoms have small magnetic dipole moments in their low-energy states, reducing the rate of dipolar-relaxation collisions. Altogether, these features provide compelling opportunities for future ultracold-atom research. Focusing on the case of atomic titanium, we identify the metastable $a ^5F_5$ state as supporting a $J rightarrow J+1$ optical transition with properties similar to the D2 transition of alkali atoms, and suited for laser cooling. The high total angular momentum and electron spin of this state suppresses leakage out of the the nearly closed optical transition to a branching ratio estimated below $sim 10^{-5}$. Following the pattern exemplified by titanium, we identify optical transitions that are suited for laser cooling of elements in the scandium group (Sc, Y, La), the titanium group (Ti, Zr), the vanadium group (V, Nb), the manganese group (Mn, Tc), and the iron group (Fe, Ru).
{"title":"Laser cooling of transition-metal atoms","authors":"Scott Eustice, K. Cassella, D. Stamper-Kurn","doi":"10.1103/physreva.102.053327","DOIUrl":"https://doi.org/10.1103/physreva.102.053327","url":null,"abstract":"We propose the application of laser cooling to a number of transition-metal atoms, allowing numerous bosonic and fermionic atomic gases to be cooled to ultra-low temperatures. The non-zero electron orbital angular momentum of these atoms implies that strongly atom-state-dependent light-atom interactions occur even for light that is far-detuned from atomic transitions. At the same time, many transition-metal atoms have small magnetic dipole moments in their low-energy states, reducing the rate of dipolar-relaxation collisions. Altogether, these features provide compelling opportunities for future ultracold-atom research. Focusing on the case of atomic titanium, we identify the metastable $a ^5F_5$ state as supporting a $J rightarrow J+1$ optical transition with properties similar to the D2 transition of alkali atoms, and suited for laser cooling. The high total angular momentum and electron spin of this state suppresses leakage out of the the nearly closed optical transition to a branching ratio estimated below $sim 10^{-5}$. Following the pattern exemplified by titanium, we identify optical transitions that are suited for laser cooling of elements in the scandium group (Sc, Y, La), the titanium group (Ti, Zr), the vanadium group (V, Nb), the manganese group (Mn, Tc), and the iron group (Fe, Ru).","PeriodicalId":8441,"journal":{"name":"arXiv: Atomic Physics","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84592839","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}
Pub Date : 2020-08-14DOI: 10.1103/PHYSREVRESEARCH.2.043083
V. Tulsky, D. Bauer
Short-time filtering of the photoionization amplitude extracted straight from the numerical solution of the time-dependent Schr"{o}dinger equation (TDSE) is used to identify dominant pathways that form photoelectron spectra in strong fields. Thereby, the "black-box nature" of TDSE solvers only giving the final spectrum is overcome, and simpler approaches, e.g., semi-classical based on the strong-field approximation, can be tested and improved. The approach also allows to suppress intercycle quantum interference between pathways removing patterns that are usually washed out in experiments.
{"title":"Numerical time-of-flight analysis of the strong-field photoeffect","authors":"V. Tulsky, D. Bauer","doi":"10.1103/PHYSREVRESEARCH.2.043083","DOIUrl":"https://doi.org/10.1103/PHYSREVRESEARCH.2.043083","url":null,"abstract":"Short-time filtering of the photoionization amplitude extracted straight from the numerical solution of the time-dependent Schr\"{o}dinger equation (TDSE) is used to identify dominant pathways that form photoelectron spectra in strong fields. Thereby, the \"black-box nature\" of TDSE solvers only giving the final spectrum is overcome, and simpler approaches, e.g., semi-classical based on the strong-field approximation, can be tested and improved. The approach also allows to suppress intercycle quantum interference between pathways removing patterns that are usually washed out in experiments.","PeriodicalId":8441,"journal":{"name":"arXiv: Atomic Physics","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82148788","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}
Y. Jiao, N. L. R. Spong, O. D. Hughes, Chloe So, T. Ilieva, K. Weatherill, C. Adams
We demonstrate a single-photon stored-light interferometer, where a photon is stored in a laser-cooled atomic ensemble in the form of a Rydberg polariton with a spatial extent of $10 times1times1mu m^3$. The photon is subject to a Ramsey sequence, i.e. `split' into a superposition of two paths. After a delay of up to 450 ns, the two paths are recombined to give an output dependent on their relative phase. The superposition time of 450 ns is equivalent to a free-space propagation distance of 135 m. We show that the interferometer fringes are sensitive to external fields, and suggest that stored-light interferometry could be useful for localized sensing applications.
{"title":"Single-Photon Stored-Light Interferometry.","authors":"Y. Jiao, N. L. R. Spong, O. D. Hughes, Chloe So, T. Ilieva, K. Weatherill, C. Adams","doi":"10.15128/r18k71nh124","DOIUrl":"https://doi.org/10.15128/r18k71nh124","url":null,"abstract":"We demonstrate a single-photon stored-light interferometer, where a photon is stored in a laser-cooled atomic ensemble in the form of a Rydberg polariton with a spatial extent of $10 times1times1mu m^3$. The photon is subject to a Ramsey sequence, i.e. `split' into a superposition of two paths. After a delay of up to 450 ns, the two paths are recombined to give an output dependent on their relative phase. The superposition time of 450 ns is equivalent to a free-space propagation distance of 135 m. We show that the interferometer fringes are sensitive to external fields, and suggest that stored-light interferometry could be useful for localized sensing applications.","PeriodicalId":8441,"journal":{"name":"arXiv: Atomic Physics","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81091120","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}
In the framework of a quasi-molecular approach, the formation of hydrogen atom in the pre-recombination period of evolution of the universe is analysed quantitatively. Calculations in an adiabatic multi-level representation enable estimates of probabilities of radiative transitions. The quasi-molecular mechanism of recombination allows the formation of hydrogen molecular ion, $H_2^+$, in its ground state. The probability of this process is comparable with the probability of the creation of atomic hydrogen. The participation of a second proton in the recombination increases the binding energy of an electron and decreases the rate of recombination of hydrogen.
{"title":"Influence of a quasi-molecular mechanism of recombination on the formation of hydrogen in the early Universe","authors":"T. Kereselidze, I. Noselidze, J. Ogilvie","doi":"10.1093/mnras/staa3622","DOIUrl":"https://doi.org/10.1093/mnras/staa3622","url":null,"abstract":"In the framework of a quasi-molecular approach, the formation of hydrogen atom in the pre-recombination period of evolution of the universe is analysed quantitatively. Calculations in an adiabatic multi-level representation enable estimates of probabilities of radiative transitions. The quasi-molecular mechanism of recombination allows the formation of hydrogen molecular ion, $H_2^+$, in its ground state. The probability of this process is comparable with the probability of the creation of atomic hydrogen. The participation of a second proton in the recombination increases the binding energy of an electron and decreases the rate of recombination of hydrogen.","PeriodicalId":8441,"journal":{"name":"arXiv: Atomic Physics","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88558032","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}
State-of-the-art magnetic field measurements performed in shielded environments with carefully controlled conditions rarely reflect the realities of those applications envisioned in the introductions of peer-reviewed publications. Nevertheless, significant advances in magnetometer sensitivity have been accompanied by serious attempts to bring these magnetometers into the challenging working environments in which they are often required. This review discusses the ways in which various (predominantly optically-pumped) magnetometer technologies have been adapted for use in a wide range of noisy and physically demanding environments.
{"title":"Sensitive magnetometry in challenging environments","authors":"K. Fu, G. Iwata, A. Wickenbrock, D. Budker","doi":"10.1116/5.0025186","DOIUrl":"https://doi.org/10.1116/5.0025186","url":null,"abstract":"State-of-the-art magnetic field measurements performed in shielded environments with carefully controlled conditions rarely reflect the realities of those applications envisioned in the introductions of peer-reviewed publications. Nevertheless, significant advances in magnetometer sensitivity have been accompanied by serious attempts to bring these magnetometers into the challenging working environments in which they are often required. This review discusses the ways in which various (predominantly optically-pumped) magnetometer technologies have been adapted for use in a wide range of noisy and physically demanding environments.","PeriodicalId":8441,"journal":{"name":"arXiv: Atomic Physics","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74607579","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}
A. Aleksanyan, R. Momier, E. Gazazyan, A. Papoyan, C. Leroy
We have analyzed the magnetic field dependences of intensities of all the optical transitions between magnetic sublevels of hyperfine levels, excited with $sigma^+$, $pi$ and $sigma^-$ polarized light, for the $D_1$ and $D_2$ lines of $^{87}$Rb and $^{85}$Rb atoms. Depending on the type of transition and the quantum numbers of involved levels, the Hamiltonian matrices are of $1times 1$, $2times 2$, $3times 3$ or $4times 4$ dimension. As an example, analytical expressions are presented for the case of $2times 2$ dimension matrices for $D_1$ line of both isotopes. Eigenvalues and eigenkets are given, and the expression for the transition intensity as a function of $B$ has been determined. It is found that some $pi$ transitions of $^{87}$Rb and $^{85}$Rb get completely canceled for certain, extremely precise, values of $B$. No cancellation occurs for $sigma^+$ or $sigma^-$ transitions of $D_1$ line. For matrices with size over $2times 2$, analytical formulas are heavy, and we have performed numerical calculations. All the $B$ values cancelling $sigma^+$, $pi$ and $sigma^-$ transitions of $D_1$ and $D_2$ lines of $^{87}$Rb and $^{85}$Rb are calculated, with an accuracy limited by the precision of the involved physical quantities. We believe our modeling can serve as a tool for determination of standardized values of magnetic field. The experimental implementation feasibility and its possible outcome are addressed. We believe the experimental realization will allow to increase precision of the physical quantities involved, in particular the upper state atomic levels energy.
{"title":"Transition cancellations of 87Rb and 85Rb atoms in a magnetic field","authors":"A. Aleksanyan, R. Momier, E. Gazazyan, A. Papoyan, C. Leroy","doi":"10.1364/josab.403862","DOIUrl":"https://doi.org/10.1364/josab.403862","url":null,"abstract":"We have analyzed the magnetic field dependences of intensities of all the optical transitions between magnetic sublevels of hyperfine levels, excited with $sigma^+$, $pi$ and $sigma^-$ polarized light, for the $D_1$ and $D_2$ lines of $^{87}$Rb and $^{85}$Rb atoms. Depending on the type of transition and the quantum numbers of involved levels, the Hamiltonian matrices are of $1times 1$, $2times 2$, $3times 3$ or $4times 4$ dimension. As an example, analytical expressions are presented for the case of $2times 2$ dimension matrices for $D_1$ line of both isotopes. Eigenvalues and eigenkets are given, and the expression for the transition intensity as a function of $B$ has been determined. It is found that some $pi$ transitions of $^{87}$Rb and $^{85}$Rb get completely canceled for certain, extremely precise, values of $B$. No cancellation occurs for $sigma^+$ or $sigma^-$ transitions of $D_1$ line. For matrices with size over $2times 2$, analytical formulas are heavy, and we have performed numerical calculations. All the $B$ values cancelling $sigma^+$, $pi$ and $sigma^-$ transitions of $D_1$ and $D_2$ lines of $^{87}$Rb and $^{85}$Rb are calculated, with an accuracy limited by the precision of the involved physical quantities. We believe our modeling can serve as a tool for determination of standardized values of magnetic field. The experimental implementation feasibility and its possible outcome are addressed. We believe the experimental realization will allow to increase precision of the physical quantities involved, in particular the upper state atomic levels energy.","PeriodicalId":8441,"journal":{"name":"arXiv: Atomic Physics","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79229075","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}
Pub Date : 2020-07-16DOI: 10.1103/physrevapplied.14.044046
P. Burdekin, S. Grandi, Rielly Newbold, R. Hoggarth, K. D. Major, A. Clark
We propose and demonstrate pump-probe spectroscopy of rubidium absorption which reveals the sub-Doppler hyperfine structure of the $^{5}$S$_{1/2} leftrightarrow$ $^{5}$P$_{3/2}$ (D2) transitions. The counter propagating pump and probe lasers are independently tunable in frequency, with the probe operating at the single-photon-level. The two-dimensional spectrum measured as the laser frequencies are scanned shows fluorescence, Doppler-broadened absorption dips and sub-Doppler features. The detuning between the pump and probe lasers allows compensation of the Doppler shift for all atomic velocities in the room temperature vapor, meaning we observe sub-Doppler features for all atoms in the beam. We detail a theoretical model of the system which incorporates fluorescence, saturation effects and optical pumping and compare this with the measured spectrum, finding a mean absolute percentage error of 4.17%. In the future this technique could assist in frequency stabilization of lasers, and the single-photon-level probe could be replaced by a single photon source.
我们提出并演示了铷吸收的泵浦探测光谱，揭示了$^{5}$ S $_{1/2} leftrightarrow$$^{5}$ P $_{3/2}$ (D2)跃迁的亚多普勒超精细结构。反向传播泵浦和探针激光器的频率可独立调谐，探针工作在单光子水平。扫描激光频率时测量的二维光谱显示出荧光、多普勒加宽吸收衰减和亚多普勒特征。泵浦激光器和探测激光器之间的失谐可以补偿室温蒸汽中所有原子速度的多普勒频移，这意味着我们可以观察到光束中所有原子的亚多普勒特征。我们详细介绍了该系统的理论模型，其中包括荧光、饱和效应和光泵浦，并将其与实测光谱进行了比较，发现平均绝对百分比误差为4.17％。在未来，该技术可以辅助激光的频率稳定，单光子级探针可以被单光子源取代。
{"title":"Single-Photon-Level Sub-Doppler Pump-Probe Spectroscopy of Rubidium","authors":"P. Burdekin, S. Grandi, Rielly Newbold, R. Hoggarth, K. D. Major, A. Clark","doi":"10.1103/physrevapplied.14.044046","DOIUrl":"https://doi.org/10.1103/physrevapplied.14.044046","url":null,"abstract":"We propose and demonstrate pump-probe spectroscopy of rubidium absorption which reveals the sub-Doppler hyperfine structure of the $^{5}$S$_{1/2} leftrightarrow$ $^{5}$P$_{3/2}$ (D2) transitions. The counter propagating pump and probe lasers are independently tunable in frequency, with the probe operating at the single-photon-level. The two-dimensional spectrum measured as the laser frequencies are scanned shows fluorescence, Doppler-broadened absorption dips and sub-Doppler features. The detuning between the pump and probe lasers allows compensation of the Doppler shift for all atomic velocities in the room temperature vapor, meaning we observe sub-Doppler features for all atoms in the beam. We detail a theoretical model of the system which incorporates fluorescence, saturation effects and optical pumping and compare this with the measured spectrum, finding a mean absolute percentage error of 4.17%. In the future this technique could assist in frequency stabilization of lasers, and the single-photon-level probe could be replaced by a single photon source.","PeriodicalId":8441,"journal":{"name":"arXiv: Atomic Physics","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78726577","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}
Yuhi Aikyo, Geert Vrijsen, T. Noel, A. Kato, M. Ivory, Jungsang Kim
We present the design and vacuum performance of a compact room-temperature trapped ion system for quantum computing, consisting of a ultra-high vacuum (UHV) package, a micro-fabricated surface trap and a small form-factor ion pump. The system is designed to maximize mechanical stability and robustness by minimizing the system size and weight. The internal volume of the UHV package is only 2 cm$^3$, a significant reduction in comparison with conventional vacuum chambers used in trapped ion experiments. We demonstrate trapping of $^{174}$Yb$^+$ ions in this system and characterize the vacuum level in the UHV package by monitoring both the rates of ion hopping in a double-well potential and ion chain reordering events. The calculated pressure in this vacuum package is about 1.5e-11 Torr, which is sufficient for the majority of current trapped ion experiments.
{"title":"Vacuum characterization of a compact room-temperature trapped ion system","authors":"Yuhi Aikyo, Geert Vrijsen, T. Noel, A. Kato, M. Ivory, Jungsang Kim","doi":"10.1063/5.0029236","DOIUrl":"https://doi.org/10.1063/5.0029236","url":null,"abstract":"We present the design and vacuum performance of a compact room-temperature trapped ion system for quantum computing, consisting of a ultra-high vacuum (UHV) package, a micro-fabricated surface trap and a small form-factor ion pump. The system is designed to maximize mechanical stability and robustness by minimizing the system size and weight. The internal volume of the UHV package is only 2 cm$^3$, a significant reduction in comparison with conventional vacuum chambers used in trapped ion experiments. We demonstrate trapping of $^{174}$Yb$^+$ ions in this system and characterize the vacuum level in the UHV package by monitoring both the rates of ion hopping in a double-well potential and ion chain reordering events. The calculated pressure in this vacuum package is about 1.5e-11 Torr, which is sufficient for the majority of current trapped ion experiments.","PeriodicalId":8441,"journal":{"name":"arXiv: Atomic Physics","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83655869","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}
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