We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-ly...We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-lying excited states to the 1s-muon state can lead to the production of electron-positron pairs.We show that the Breit interaction determines the transition probabilities for states with nonzero orbital momentum.We show that the pair production arises mainly from the decay of the 2p states.Thus,the Breit interaction governs electron-positron pair production in bound-bound muon transitions.This process offers a unique opportunity to explore quantum electrodynamics in strong fields,as well as a class of nonradiative transitions involving electron-positron pair production.展开更多
We take the （μ^±e^-＋） system as an example, but restrict ourselves to highlight the states with quantum number J^P = 0^-, to explore the different contents of the instantaneous Bethe-Salpeter （BS） equation ...We take the （μ^±e^-＋） system as an example, but restrict ourselves to highlight the states with quantum number J^P = 0^-, to explore the different contents of the instantaneous Bethe-Salpeter （BS） equation and its analog, the relativistic version of Breit equation, by solving them exactly. The results show that the two equations are not equivalent, although they are analogous. Furthermore, since the Breit equation contains extra un-physical solutions, so we point out that it should be abandoned if one wishes to have an accurate description of the bound states for the instantaneous interacting binding systems.展开更多
[Objectives] The aim was to study chemical components of cultivated and wild Pinellia ternate(Thunb.) Breit and Typhonium flagelliforme(Lodd.) Blume by metabolomics technology based on UPLC-ESI-HRMS^n. [Methods] Chemi...[Objectives] The aim was to study chemical components of cultivated and wild Pinellia ternate(Thunb.) Breit and Typhonium flagelliforme(Lodd.) Blume by metabolomics technology based on UPLC-ESI-HRMS^n. [Methods] Chemical components of 27 samples of cultivated and wild P. ternate and T. flagelliforme were detected by using UPLC-ESI-HRMS^ntechnology. Differential markers between P. ternate and T. flagelliforme as well as cultivated and wild P. ternate were screened and identified by principal component analysis(PCA) and orthogonal partial least square-discriminate analysis(OPLS-DA). [Results]12 components of P. ternate(cultivated and wild variety) and T.flagelliforme and three components of cultivated and wild P. ternate were screened and identified by OPLS-DA. N-Acetyl-6-hydroxy-L-tryptophan and N-Phenylacetylglutamic were not detected in P. ternate,and these two components can be used as potential markers of P. ternate and T. flagelliforme. [Conclusions]UPLC-ESI-HRMS^n-based metabolomics technology could be used to quickly identify the chemical constituents of P. ternate and effectively distinguish P. ternate and T. flagelliforme,which has reference significance for the quality control of P. ternate.展开更多
We theoretically investigate the electron transmission through a seven-layer semiconductor heterostructure with the Dresselhaus spin-orbit coupling under two applied oscillating fields. Numerical results show that bot...We theoretically investigate the electron transmission through a seven-layer semiconductor heterostructure with the Dresselhaus spin-orbit coupling under two applied oscillating fields. Numerical results show that both of the spindependent symmetric Breit-Wigner and the asymmetric Fano resonances appear and that the properties of these two types of resonance peaks are dependent on the amplitudc and the relative phases of the two applicd oscillating fields. The modulation of the spin-polarization efficiency of transmitted electrons by the relative phase is also discussed.展开更多
The transition energies, E1 transitional oscillator strengths of the spin-allowed as well as the spin-forbidden and the corresponding transition rates, and complete M1, E2, M2 forbidden transition rates for 1s^(2), 1s...The transition energies, E1 transitional oscillator strengths of the spin-allowed as well as the spin-forbidden and the corresponding transition rates, and complete M1, E2, M2 forbidden transition rates for 1s^(2), 1s2s, and 1s2p states of He I, are investigated using the multi-configuration Dirac–Hartree–Fock method. In the subsequent relativistic configuration interaction computations, the Breit interaction and the QED effect are considered as perturbation, separately. Our transition energies, oscillator strengths, and transition rates are in good agreement with the experimental and other theoretical results. As a result, the QED effect is not important for helium atoms, however, the effect of the Breit interaction plays a significant role in the transition energies, the oscillator strengths and transition rates.展开更多
We propose an all-optical,single-laser-pulse scheme for generating a dense relativistic strongly magnetized electron-positron pair plasma.The scheme involves the interaction of an extremely intense(I■10^(24) W/cm^(2)...We propose an all-optical,single-laser-pulse scheme for generating a dense relativistic strongly magnetized electron-positron pair plasma.The scheme involves the interaction of an extremely intense(I■10^(24) W/cm^(2))circularly polarized laser pulse with a solid-density target containing a conical cavity.Through full-scale three-dimensional particle-in-cell simulations that account for quantum electrodynamic effects,it is shown that this interaction results in two significant outcomes:first,the generation of quasi-static magnetic fields reaching tens of gigagauss,and,second,the production of large quantities of electron-positron pairs(up to 10^(13))via the Breit-Wheeler process.The e^(-)e^(+)plasma becomes trapped in the magnetic field and remains confined in a small volume for hundreds of femtoseconds,far exceeding the laser timescale.The dependence of pair plasma parameters,as well as the efficiency of plasma production and confinement,is discussed in relation to the properties of the laser pulse and the target.Realizing this scheme experimentally would enable the investigation of physical processes relevant to extreme astrophysical environments.展开更多
For the observed line at 799.23°A in tungsten EBIT experiment,which was assigned to be^(3)F_(4)^(o)−^(3)F_(3)^(o)([Ar]4s^(2)4p^(5)4d)of W^(38+)ion,there were noticeable deviations for most calculated wavelengths ...For the observed line at 799.23°A in tungsten EBIT experiment,which was assigned to be^(3)F_(4)^(o)−^(3)F_(3)^(o)([Ar]4s^(2)4p^(5)4d)of W^(38+)ion,there were noticeable deviations for most calculated wavelengths from the measured value.To clarify this issue,we carry out an extensive calculation for energy levels and transition properties of W^(38+)ion using the multi-configuration Dirac–Hartree–Fock and relativistic configuration interaction method,in which more deeper inner core electron correlations are included,and different forms of Breit interaction as well as quantum electrodynamics corrections are investigated.It is found that the inner core electron correlations can affect the total energy of levels,while only slightly modify the excited energy of levels in 4s^(2)4p^(5)4d complex.The present calculated wavelengths agree with the corresponding measured values excellently except the line at 799.23Å.Thus we are strongly suspicious this line should be misidentified,and suggest that new experiment with higher resolution and spectra analysis based on more accurate atomic data should be performed for W^(38+)ion.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1602501)the National Natural Science Foundation of China(Grant No.12011530060)+1 种基金supported solely by the Russian Science Foundation(Grant No.22-12-00043)supported by the Chinese Academy of Sciences(CAS)Presidents International Fellowship Initiative(PIFI)(Grant Nos.2018VMB0016 and 2022VMC0002),respectively。
文摘We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-lying excited states to the 1s-muon state can lead to the production of electron-positron pairs.We show that the Breit interaction determines the transition probabilities for states with nonzero orbital momentum.We show that the pair production arises mainly from the decay of the 2p states.Thus,the Breit interaction governs electron-positron pair production in bound-bound muon transitions.This process offers a unique opportunity to explore quantum electrodynamics in strong fields,as well as a class of nonradiative transitions involving electron-positron pair production.
文摘We take the （μ^±e^-＋） system as an example, but restrict ourselves to highlight the states with quantum number J^P = 0^-, to explore the different contents of the instantaneous Bethe-Salpeter （BS） equation and its analog, the relativistic version of Breit equation, by solving them exactly. The results show that the two equations are not equivalent, although they are analogous. Furthermore, since the Breit equation contains extra un-physical solutions, so we point out that it should be abandoned if one wishes to have an accurate description of the bound states for the instantaneous interacting binding systems.
基金Supported by Preferred Funding Plan of Science and Technology Activities Project for Overseas Students in Sichuan Province(2018-68)Key Project for Central Universities of Southwest Minzu University in 2018(2018NZD18)+1 种基金Research Project of Sichuan Province(2019YFS0174,2019YFS0191,2018JY0069)Innovative Scientific Research Project for Postgraduates of Southwest Minzu University(CX2017SZ092)
文摘[Objectives] The aim was to study chemical components of cultivated and wild Pinellia ternate(Thunb.) Breit and Typhonium flagelliforme(Lodd.) Blume by metabolomics technology based on UPLC-ESI-HRMS^n. [Methods] Chemical components of 27 samples of cultivated and wild P. ternate and T. flagelliforme were detected by using UPLC-ESI-HRMS^ntechnology. Differential markers between P. ternate and T. flagelliforme as well as cultivated and wild P. ternate were screened and identified by principal component analysis(PCA) and orthogonal partial least square-discriminate analysis(OPLS-DA). [Results]12 components of P. ternate(cultivated and wild variety) and T.flagelliforme and three components of cultivated and wild P. ternate were screened and identified by OPLS-DA. N-Acetyl-6-hydroxy-L-tryptophan and N-Phenylacetylglutamic were not detected in P. ternate,and these two components can be used as potential markers of P. ternate and T. flagelliforme. [Conclusions]UPLC-ESI-HRMS^n-based metabolomics technology could be used to quickly identify the chemical constituents of P. ternate and effectively distinguish P. ternate and T. flagelliforme,which has reference significance for the quality control of P. ternate.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10974046)Natural Science Foundation of Hubei Province of China (Grant No. 2009CDB360)the Key Project of Education Department of Hubei Province of China (Grant No. D20101004)
文摘We theoretically investigate the electron transmission through a seven-layer semiconductor heterostructure with the Dresselhaus spin-orbit coupling under two applied oscillating fields. Numerical results show that both of the spindependent symmetric Breit-Wigner and the asymmetric Fano resonances appear and that the properties of these two types of resonance peaks are dependent on the amplitudc and the relative phases of the two applicd oscillating fields. The modulation of the spin-polarization efficiency of transmitted electrons by the relative phase is also discussed.
基金Supported by the National Key Research and Development Program of China (Grant No. 2017YFA0402300)the National Natural Science Foundation of China (Grant Nos. 11774344 and 11474033)。
文摘The transition energies, E1 transitional oscillator strengths of the spin-allowed as well as the spin-forbidden and the corresponding transition rates, and complete M1, E2, M2 forbidden transition rates for 1s^(2), 1s2s, and 1s2p states of He I, are investigated using the multi-configuration Dirac–Hartree–Fock method. In the subsequent relativistic configuration interaction computations, the Breit interaction and the QED effect are considered as perturbation, separately. Our transition energies, oscillator strengths, and transition rates are in good agreement with the experimental and other theoretical results. As a result, the QED effect is not important for helium atoms, however, the effect of the Breit interaction plays a significant role in the transition energies, the oscillator strengths and transition rates.
基金supported by BMBF-Project No.05P24PF1DFG Project No.PU 213/6-3.
文摘We propose an all-optical,single-laser-pulse scheme for generating a dense relativistic strongly magnetized electron-positron pair plasma.The scheme involves the interaction of an extremely intense(I■10^(24) W/cm^(2))circularly polarized laser pulse with a solid-density target containing a conical cavity.Through full-scale three-dimensional particle-in-cell simulations that account for quantum electrodynamic effects,it is shown that this interaction results in two significant outcomes:first,the generation of quasi-static magnetic fields reaching tens of gigagauss,and,second,the production of large quantities of electron-positron pairs(up to 10^(13))via the Breit-Wheeler process.The e^(-)e^(+)plasma becomes trapped in the magnetic field and remains confined in a small volume for hundreds of femtoseconds,far exceeding the laser timescale.The dependence of pair plasma parameters,as well as the efficiency of plasma production and confinement,is discussed in relation to the properties of the laser pulse and the target.Realizing this scheme experimentally would enable the investigation of physical processes relevant to extreme astrophysical environments.
基金supported by the Science Challenge Project of China Academy of Engineering Physics(CAEP)(Grant No.TZ2018005)the National Natural Science Foundation of China(Grant Nos.12474277,12374259,12104095,12074081,and 12074082).
文摘For the observed line at 799.23°A in tungsten EBIT experiment,which was assigned to be^(3)F_(4)^(o)−^(3)F_(3)^(o)([Ar]4s^(2)4p^(5)4d)of W^(38+)ion,there were noticeable deviations for most calculated wavelengths from the measured value.To clarify this issue,we carry out an extensive calculation for energy levels and transition properties of W^(38+)ion using the multi-configuration Dirac–Hartree–Fock and relativistic configuration interaction method,in which more deeper inner core electron correlations are included,and different forms of Breit interaction as well as quantum electrodynamics corrections are investigated.It is found that the inner core electron correlations can affect the total energy of levels,while only slightly modify the excited energy of levels in 4s^(2)4p^(5)4d complex.The present calculated wavelengths agree with the corresponding measured values excellently except the line at 799.23Å.Thus we are strongly suspicious this line should be misidentified,and suggest that new experiment with higher resolution and spectra analysis based on more accurate atomic data should be performed for W^(38+)ion.
