The Pryce(e)spin and position operators of the quantum theory of Dirac's free field were re-defined and studied recently with the help of a new spin symmetry and suitable spectral representations[Eur.Phys.J.C 82,1...The Pryce(e)spin and position operators of the quantum theory of Dirac's free field were re-defined and studied recently with the help of a new spin symmetry and suitable spectral representations[Eur.Phys.J.C 82,1073(2022)].This approach is generalized here,associating a pair of integral operators acting directly on particle and antiparticle wave spinors in momentum representation to any integral operator in configuration representation,acting on mode spinors.This framework allows an effective quantization procedure,giving a large set of one-particle operators with physical meaning as the spin and orbital parts of the isometry generators,the Pauli-Lubanski and position operators,or other spin-type operators proposed to date.Special attention is paid to the operators that mix the particle and antiparticle sectors whose off-diagonal associated operators have oscillating terms producing Zitterbevegung.The principal operators of this type,including the usual coordinate operator,are derived here for the first time.As an application,it is shown that an apparatus measuring these new observables may prepare and detect oneparticle wave packets moving uniformly without Zitterbewegung or spin dynamics,spreading in time normally as any other relativistic or even non-relativistic wave packet.展开更多
Employing both the Dirac R-matrix and the relativistic distorted wave with independent process and isolated reso- nance approaches, we report resonance enhanced electron impact excitation data （specifically, effectiv...Employing both the Dirac R-matrix and the relativistic distorted wave with independent process and isolated reso- nance approaches, we report resonance enhanced electron impact excitation data （specifically, effective collision strengths） among the lowest 41 levels from the n = 3 configurations of Cu XV. The results show that the latter approach can obtain resonance contributions reasonably well for most excitations of Cu XV, though a comparison between the two approaches shows that the close-coupling effects are truly significant for rather weak excitations, especially for two-electron excitations from the 3s3p4 to 3s23p23d configuration. Resonance contributions are significant （more than two orders of magnitude） for many excitations and dramatically influence the line intensity ratios associated with density diagnostics.展开更多
文摘The Pryce(e)spin and position operators of the quantum theory of Dirac's free field were re-defined and studied recently with the help of a new spin symmetry and suitable spectral representations[Eur.Phys.J.C 82,1073(2022)].This approach is generalized here,associating a pair of integral operators acting directly on particle and antiparticle wave spinors in momentum representation to any integral operator in configuration representation,acting on mode spinors.This framework allows an effective quantization procedure,giving a large set of one-particle operators with physical meaning as the spin and orbital parts of the isometry generators,the Pauli-Lubanski and position operators,or other spin-type operators proposed to date.Special attention is paid to the operators that mix the particle and antiparticle sectors whose off-diagonal associated operators have oscillating terms producing Zitterbevegung.The principal operators of this type,including the usual coordinate operator,are derived here for the first time.As an application,it is shown that an apparatus measuring these new observables may prepare and detect oneparticle wave packets moving uniformly without Zitterbewegung or spin dynamics,spreading in time normally as any other relativistic or even non-relativistic wave packet.
基金supported by the National Natural Science Foundation of China(Grant Nos.11076009 and 11374062)the Chinese Association of Atomic and Molecular Data,the Chinese National Fusion Project for ITER(Grant No.2015GB117000)the Leading Academic Discipline Project of Shanghai,China(Grant No.B107)
文摘Employing both the Dirac R-matrix and the relativistic distorted wave with independent process and isolated reso- nance approaches, we report resonance enhanced electron impact excitation data （specifically, effective collision strengths） among the lowest 41 levels from the n = 3 configurations of Cu XV. The results show that the latter approach can obtain resonance contributions reasonably well for most excitations of Cu XV, though a comparison between the two approaches shows that the close-coupling effects are truly significant for rather weak excitations, especially for two-electron excitations from the 3s3p4 to 3s23p23d configuration. Resonance contributions are significant （more than two orders of magnitude） for many excitations and dramatically influence the line intensity ratios associated with density diagnostics.
