相关论文: The 2S-2P Lamb Shift in He+

A two-step, two-color laser spectroscopy technique has been used to measure the hyperfine splitting of the 7p$_{1/2}$ excited state in $^{203}$Tl and $^{205}$Tl, as well as the isotope shift within the 7s$_{1/2}$ - 7p$_{1/2}$ transition.…

We consider the time evolution of the occupation probabilities for the 2s-2p transition in a hydrogen atom interacting with an external field, V(t). A two-state model and a dipole approximation are used. In the case of degenerate energy…

Using first-principles calculations, we identify magic wavelengths for the 2s-2p and 2s-3p transitions in lithium. The ns and np atomic levels have the same ac Stark shifts at the corresponding magic wavelength, which facilitates…

The evolution of the electromagnetic coupling, alpha, in the momentum-transfer range 1800GeV^2 < -Q^2 < 21600GeV^2 is studied with about 40000 Bhabha-scattering events collected with the L3 detector at LEP at centre-of-mass energies…

We report on measurements on the 5S-6P rubidium transition frequencies for rubidium isotopes with an absolute uncertainty of better than \SI{450}{kHz} for the 5S $\rightarrow$ 6P$_{1/2}$ transition and \SI{20}{kHz} for the 5S $\rightarrow$…

An experiment is proposed to excite the 'forbidden' 1s2s 3S1 - 1s2s 1S0 magnetic dipole (M1) transition at 1557 nm in a collimated and slow atomic beam of metastable helium atoms. It is demonstrated that an excitation rate of 5000 /s can be…

Let f be a classical holomorphic cusp form for SL_2(Z) of weight k which is a normalized eigenfunction for the Hecke algebra, and let \lambda(n) be its eigenvalues. In this paper we study "shifted convolution sums" of the eigenvalues…

The last unknown contribution to hydrogen energy levels at order m alpha ^7, due to the slope of the Dirac form factor at three loops, is evaluated in a closed analytical form. The resulting shift of the hydrogen nS energy level is found to…

The Lamb shift in muonic hydrogen was measured some time ago to a high accuracy. The theoretical prediction of this value is very sensitive to the proton-finite-size effects. The proton radius extracted from muonic hydrogen is in…

Recently, important updates were made for the hadronic contribution to the theoretical prediction of g-2. The isospin-breaking-corrections, needed in the comparison of the two pion spectral functions from tau decays and e+e- annihilations,…

We report precision measurement of aluminum atoms ${^{2}P_{1/2}}-{^{2}S_{1/2}}$ transition at 394 nm and ${^{2}P_{3/2}}-{^{2}S_{1/2}}$ transition at 396 nm in a hollow-cathode lamp (HCL). Both absorption spectroscopy and saturated…

The nuclear size effect on the one-loop self energy and vacuum polarization is evaluated for the 1s, 2s, 3s, 2p_{1/2}, and 2p_{3/2} states of hydrogen-like ions. The calculation is performed to all orders in the binding nuclear strength…

A simple but effective method for regularization-renormalization (R-R) is proposed for handling the Feynman diagram integral (FDI) at one loop level in quantum electrodynamics (QED). The divergence is substituted by some constants to be…

Over a two-year duration, we have compared the frequency of the 199Hg+ 5d106s 2S 1/2 (F=0)<-> 5d9 6s2 2D 5/2 (F=2) electric-quadrupole transition at 282 nm with the frequency of the ground-state hyperfine splitting in neutral 133Cs. These…

Frequency shifts of the ^199Hg^+ 5d^10 6s ^2S_1/2 (F=0, M_F=0) to 5d^9 6s^2 ^2D_5/2 (F=2, M_F=0) electric-quadrupole transition at 282 nm due to external fields are calculated, based on a combination of measured atomic parameters and ab…

In order to explain discrepancies between theoretical predictions and experimental data for the helium fine structure, we check and recalculate all theoretical contributions up to orders m\alpha^7 and m^2/M\alpha^6. The previous result for…

New corrections to the energy of $S$-levels of positronium of order $m\alpha^6$ which are as large as several hundred kilohertz are obtained. A new recoil correction of order $\alpha(Z\alpha)^5(m/M)m$ to the Lamb shift in hydrogen is…

We present the first observation of the 1s2p 3P2 ? 1s2s 3S1 transition in He-like uranium. The experiment was performed at the internal gas-jet target of the ESR storage ring at GSI exploiting a Bragg crystal spectrometer and a germanium…

The uncertainty in the contribution to the Lamb shift in muonic hydrogen, $\Delta E^{subt}$ arising from proton polarizability effects in the two-photon exchange diagram at large virtual photon momenta is shown large enough to account for…

Methods of bound-state QED that treat the self-energy contributions to the Lamb shift within the partial-wave expansion usually face the problem of slow convergence of the latter. Inspired by an approach formulated in [J. Sapirstein and K.…