13,002 research outputs found
Assessment of the Fluorescence and Auger Data Base used in Plasma Modeling
We have investigated the accuracy of the 1s-vacancy fluorescence data base of
Kaastra & Mewe (1993, A&AS, 97, 443) resulting from the initial atomic physics
calculations and the subsequent scaling along isoelectronic sequences. In
particular, we have focused on the relatively simple Be-like and F-like
1s-vacancy sequences. We find that the earlier atomic physics calculations for
the oscillator strengths and autoionization rates of singly-charged B II and Ne
II are in sufficient agreement with our present calculations. However, the
substantial charge dependence of these quantities along each isoelectronic
sequence, the incorrect configuration averaging used for B II, and the neglect
of spin-orbit effects (which become important at high-Z) all cast doubt on the
reliability of the Kaastra & Mewe data for application to plasma modeling.Comment: 19 pages with 6 figures, AAS TeX, accepted for publication in Ap
On Exchange of Orbital Angular Momentum Between Twisted Photons and Atomic Electrons
We obtain an expression for the matrix element for a twisted
(Laguerre-Gaussian profile) photon scattering from a hydrogen atom. We consider
photons incoming with an orbital angular momentum (OAM) of ,
carried by a factor of not present in a plane-wave or pure
Gaussian profile beam. The nature of the transfer of units of OAM from
the photon to the azimuthal atomic quantum number of the atom is investigated.
We obtain simple formulae for these OAM flip transitions for elastic forward
scattering of twisted photons when the photon wavelength is large
compared with the atomic target size , and small compared the Rayleigh range
, which characterizes the collimation length of the twisted photon beam.Comment: 16 page
Time Ordering in Kicked Qubits
We examine time ordering effects in strongly, suddenly perturbed two-state
quantum systems (kicked qubits) by comparing results with time ordering to
results without time ordering. Simple analytic expressions are given for state
occupation amplitudes and probabilities for singly and multiply kicked qubits.
We investigate the limit of no time ordering, which can differ in different
representations.Comment: 26 pages, 5 figure
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