640 research outputs found
QED theory of the nuclear recoil effect in atoms
The quantum electrodynamic theory of the nuclear recoil effect in atoms to
all orders in \alpha Z is formulated. The nuclear recoil corrections for atoms
with one and two electrons over closed shells are considered in detail. The
problem of the composite nuclear structure in the theory of the nuclear recoil
effect is discussed.Comment: 20 pages, 6 figures, Late
Virial relations for the Dirac equation and their applications to calculations of H-like atoms
Virial relations for the Dirac equation in a central field and their
applications to calculations of H-like atoms are considered. It is demonstrated
that using these relations allows one to evaluate various average values for a
hydrogenlike atom. The corresponding relations for non-diagonal matrix elements
provide an effective method for analytical evaluations of infinite sums that
occur in calculations based on using the reduced Coulomb-Green function. In
particular, this method can be used for calculations of higher-order
corrections to the hyperfine splitting and to the g factor in hydrogenlike
atoms.Comment: Invited talk at PSAS 2002, St.Petersburg; 19 pages, 1 figur
Interelectronic-interaction effect on the transition probability in high-Z He-like ions
The interelectronic-interaction effect on the transition probabilities in
high-Z He-like ions is investigated within a systematic quantum electrodynamic
approach. The calculation formulas for the interelectronic-interaction
corrections of first order in 1/Z are derived using the two-time Green function
method. These formulas are employed for numerical evaluations of the magnetic
transition probabilities in heliumlike ions. The results of the calculations
are compared with experimental values and previous calculations
Two-loop self-energy contribution to the Lamb shift in H-like ions
The two-loop self-energy correction is evaluated to all orders in Z\alpha for
the ground-state Lamb shift of H-like ions with Z >= 10, where Z is the nuclear
charge number and \alpha is the fine structure constant. The results obtained
are compared with the analytical values for the Z\alpha-expansion coefficients.
An extrapolation of the all-order numerical results to Z=1 is presented and
implications of our calculation for the hydrogen Lamb shift are discussed
QED corrections to the parity-nonconserving 6s-7s amplitude in Cs
The complete gauge-invariant set of the one-loop QED corrections to the
parity-nonconserving 6s-7s amplitude in Cs is evaluated to all orders
in using a local version of the Dirac-Hartree-Fock potential. The
calculations are peformed in both length and velocity gauges for the absorbed
photon. The total binding QED correction is found to be -0.27(3)%, which
differs from previous evaluations of this effect. The weak charge of
Cs, derived using two most accurate values of the vector transition
polarizability , is for and for . The first value
deviates by from the prediction of the Standard Model, while the
second one is in perfect agreement with it.Comment: 4 pages, 1 figure, 2 table
Two-loop self-energy correction in H-like ions
A part of the two-loop self-energy correction, the so-called P term, is
evaluated numerically for the 1s state to all orders in Z\alpha. Our
calculation, combined with the previous investigation [S. Mallampalli and J.
Sapirstein, Phys. Rev. A 57, 1548 (1998)], yields the total answer for the
two-loop self-energy correction in H-like uranium and bismuth. As a result, the
major uncertainty is eliminated from the theoretical prediction for the Lamb
shift in these systems. The total value of the ground-state Lamb shift in
H-like uranium is found to be 463.93(50) eV.Comment: RevTex, 29 pages, 5 figure
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