Radiative corrections to the light muonic atoms decay rate

Radiative corrections to the decay rate in low-Z hydrogen-like muonic atoms are considered. The correction is due to the Uehling potential and it has the relative order of α. The numerical results are reported for the 2p → 1s transition for atoms with nuclear charge up to Z = 10.     

Self-energy correction to the wave function in the effect of parity violation for the amplitude of the 6s–7s transition in the 133Cs atom

The quantum electrodynamic self-energy correction to the wave function in the effect of parity violation for the amplitude of the 6s–7s transition in the ¹³³Cs atom is calculated in explicit form without using the nonrelativistic approximation for the self-energy operator. The result obtained refines some previous estimates and indicates that the correction to the parity violation may be comparable with the corresponding correction to the vacuum polarization. The necessity of taking complete relativistic account of all the quantum electrodynamic corrections in calculations of the electroweak charge Q _W in atomic systems is shown.     

Analytical expressions for the evaluation of vacuum-polarization potentials in muonic atoms

Exact analytical expressions in terms of known transcendental functions are given for the evaluation of the Uehling vacuum-polarization potential induced by a static spherically-symmetrric charge distribution.     

Vacuum polarization by a Coulomb center and a strong magnetic field. Uehling's correction

The problem of vacuum polarization by the Coulomb field of the nucleus and a constant homogeneous magnetic field is examined by the proper time method. For this the magnetic field is exactly taken into account, and the Coulomb field is considered by perturbation theory. In the case of a magnetic field equal to zero, we calculate the change of the Coulomb potential which results from vacuum polarization. The result obtained coincides with the well-known Uehling correction.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 86–92, September 1986.     

Vacuum Polarisation Effects in the Lorentz Violating Electrodynamics

In this work we reconsider the one loop calculation for the vacuum polarisation tensor in the Lorentz violating quantum electrodynamics. The electron propagator is “dressed” by a Lorentz breaking extra term in the fermion Lagrangian density. We check gauge invariance and use the Schwinger–Dyson equation to discuss the full photon propagator. After a discussion on a possible photon mass shift, we show how a finite quantum correction can be chosen in a unique way in order to ensure—in the spirit of spontaneously broken theories—the standard normalisation conditions for the vacuum polarisation tensor. Then we comment on possible observable physical consequences on the Lamb-shift.     

Messung der zirkularen Polarisation der inneren und äußeren Bremsstrahlung

The polarisation of the internal bremsstrahlung γ's was detected by the Compton-forward-scattering with polarised electrons for three differentβ-decays: 1. for the allowed transition (P³²), 2. for the unique forbidden transition (Sr⁹⁰+Y⁹⁰), and 3. for the forbidden transition with forbidden spectrum (Bi²¹⁰=RaE). The detected polarisation values of P³² and (Sr⁹⁰+Y⁹⁰) agree with the theoretical values for the allowed transitions. The detected polarisation values for Bi²¹⁰ are smaller than the theoretical values of the allowedβ-transition by a factor of 0.62±0.08. The polarisation of the external bremsstrahlung was measured as a function of the atomic number (Z) using thick absorbers. The polarisation of the external bremsstrahlung decreases slowly with the increase of the atomic number. The polarisation of bremsstrahlung, which was extrapolated to an absorber with atomic numberZ=0, is in well agreement with the theoretical values of the infinitively thin absorbers.     

Pauli principle corrections in particle-hole state densities

A recent method for calculating particle-hole state densities is shown to be exact only when the number of excited particles equals the number of excited holes. Modifications are proposed for the cases wherep ≠ h. For thep=h case, comparisons of the exact results with the Williams analytical formula had pointed to inadequacies in the latter, but were made without considering the need for an energy dependent Pauli correction term. More careful investigation supports the continued use of the Williams formula with the appropriate Pauli correction term.     

The effect of vacuum polarisation in the calculation of internal conversion coefficients

The effect of vacuum polarisation on internal conversion coefficients is investigated for the nuclear charge numbersZ=26 andZ=80; it contributes less than one percent to the conversion rate.     

Thermodynamics and relativistic kinetic theory for <Emphasis Type="Italic">q</Emphasis>-generalized Bose–Einstein and Fermi–Dirac systems

The thermodynamics and covariant kinetic theory are elaborately investigated in a non-extensive environment considering the non-extensive generalization of Bose–Einstein (BE) and Fermi–Dirac (FD) statistics. Starting with Tsallis’ entropy formula, the fundamental principles of thermostatistics are established for a grand canonical system having q-generalized BE/FD degrees of freedom. Many particle kinetic theory is set up in terms of the relativistic transport equation with q-generalized Uehling–Uhlenbeck collision term. The conservation laws are realized in terms of appropriate moments of the transport equation. The thermodynamic quantities are obtained in a weak non-extensive environment for a massive pion–nucleon and a massless quark–gluon system with non-zero baryon chemical potential. In order to get an estimate of the impact of non-extensivity on the system dynamics, the q-modified Debye mass and hence the q-modified effective coupling are estimated for a quark–gluon system.     

Entropic Corrections to Coulomb’s Law

Two well-known quantum corrections to the area law have been introduced in the literatures, namely, logarithmic and power-law corrections. Logarithmic corrections, arises from loop quantum gravity due to thermal equilibrium fluctuations and quantum fluctuations, while, power-law correction appears in dealing with the entanglement of quantum fields in and out the horizon. Inspired by Verlinde’s argument on the entropic force, and assuming the quantum corrected relation for the entropy, we propose the entropic origin for the Coulomb’s law in this note. Also we investigate the Uehling potential as a radiative correction to Coulomb potential in 1-loop order and show that for some value of distance the entropic corrections of the Coulomb’s law is compatible with the vacuum-polarization correction in QED. So, we derive modified Coulomb’s law as well as the entropy corrected Poisson’s equation which governing the evolution of the scalar potential ϕ. Our study further supports the unification of gravity and electromagnetic interactions based on the holographic principle.     

? expansions in semiclassical theories for systems with smooth potentials and discrete symmetries

We extend a theory of first order ? corrections to Gutzwiller’s trace formula for systems with a smooth potential to systems with discrete symmetries and, as an example, apply the method to the two-dimensional hydrogen atom in a uniform magnetic field. We exploit the C_4v-symmetry of the system in the calculation of the correction terms. The numerical results for the semiclassical values will be compared with values extracted from exact quantum mechanical calculations. The comparison shows an excellent agreement and demonstrates the power of the ? expansion method.     

The shift of atomic ground state by a limited nonresonant moderately strong laser field

The shift of the atomic ground state due to the interaction with an external limited nonresonant laser field and vacuum fluctuation is calculated in resolvent formalism. The shift operator ¯R is taken to the fourth order of perturbation expansion. It is shown that the term which mixes these two interactions gives a slight correction to the total shift, which can be expressed by the Lamb shift of the excited state.     

Breit and Quantum Electrodynamics Energy Contributions in Multielectron Atoms from the Relativistic Screened Hydrogenic Model

The correction to the Coulomb repulsion between two electrons due to the exchange of a transverse photon, referred to as the Breit interaction, as well as the main quantum electrodynamics contributions to the atomic energies (self-energy and vacuum polarization), are calculated using the recently formulated relativistic screened hydrogenic model. Comparison with the results of multiconfiguration Dirac-Hartree-Fock calculations and experimental X-ray energies is made.     

New definition for the hadronic contribution to the muon anomalous magnetic moment

A new definition is proposed for the hadronic contribution to the muon anomalous magnetic moment that is based on the inclusion of the effects of vacuum polarization by leptons into the cross section for one-photon annihilation of a lepton pair into hadrons. The formula for the hadronic contribution includes the convolution of the measured cross section for annihilation into hadrons with a certain standard function. This remark concerns radiative correction to this function. A particular form has been proposed for this correction. It has been shown that the use of the new function makes it possible to reduce the uncertainty in such contributions due to radiative correctioins to δa _h/a _h ～ 10^?4.     

Renormalization of the two-photon vacuum polarization and the self energy vacuum polarization for a tightly bound electron

The renormalization method of Bogoljubov-Parasiuk-Hepp-Zimmermann (BPHZ) is used in order to derive the renormalized energy shift due to the gauge invariant K?llén-Sabry diagram of the two-photon vacuum polarization (VPVP) as well as the self energy vacuum polarization S(VP)E beyond the Uehling approximation. It is outlined, that no outer renormalization is required for the two-photon vacuum polarization and that only the inner renormalization has to be accomplished. It is shown that the so-called nongauge invariant spurious term is absent for a wide class of vacuum polarization (VP) diagrams if one applies the widely used spherical expansion of bound and free-electron propagator. This simplifies significantly calculations in bound state quantum electrodynamics. As one result of our paper the use of the BPHZ-approach in bound state QED is established. Received 28 September 2001     

Lamb shift in muonic hydrogen—I. Verification and update of theoretical predictions

In view of the recently observed discrepancy of theory and experiment for muonic hydrogen [R. Pohl et al., Nature 466 (2010) 213], we reexamine the theory on which the quantum electrodynamic (QED) predictions are based. In particular, we update the theory of the 2P–2S Lamb shift, by calculating the self-energy of the bound muon in the full Coulomb + vacuum polarization (Uehling) potential. We also investigate the relativistic two-body corrections to the vacuum polarization shift, and we analyze the influence of the shape of the nuclear charge distribution on the proton radius determination. The uncertainty associated with the third Zemach moment 〈r³〉₂ in the determination of the proton radius from the measurement is estimated. An updated theoretical prediction for the 2S–2P transition is given.     

Corrections to the wave function and the hyperfine structure in exotic atoms

We present an analytical evaluation of radiative corrections in exotic atoms induced by the one-loop electronic vacuum polarization. We evaluate corrections to the energy levels, to the wave function (at the origin) and to the hyperfine structure. We treat all corrections analytically within a non-relativistic approximation. Agreement is found with a few available numerical results. The analytical treatment allows to determine the asymptotic forms of the corrections in the limit of a small atomic radius, which for the atomic systems considered corresponds to a large mass of the constituent particle as compared to the electron mass. The asymptotics can be verified using the effective charge approach. Received: 28 January 1998 / Accepted: 13 March 1998     

电子阻止本领Se(E)的z振荡及其计算

本文应用Hartree-Fock-Slater势能代替Thomas-Fermi势能,得出电子阻止本领S_e(E)的归一化关系式;同时,结合有效原子序数概念,得出能量对S_e(E)影响的关系式,利用前一关系式,定量计算了S_e(E)随离子和靶原子的原子序数z变化的振荡关系,计算结果与实验值相当符合,利用后一关系式,定量计算了多种离子-靶体系的S_e(E),与文献[1]的关系式比较,本文结果更好地符合实验值,而且有更广的能量适用范 关键词：