Related papers: Two-Loop Bethe Logarithms for Higher Excited S Lev…
We present results on the self-energy correction to the energy levels of hydrogen and hydrogenlike ions. The self energy represents the largest QED correction to the relativistic (Dirac-Coulomb) energy of a bound electron. We focus on the…
A search for double beta decays of $^{110}$Pd and $^{102}$Pd into excited states of the daughter nuclides has been performed using three ultra-low background gamma-spectrometry measurements in the Felsenkeller laboratory, Germany, the HADES…
We review the Bethe-Salpeter equation (BSE) approach to the calculation of electronic excitation energies of molecular systems. We recall the general Green's function many-theory formalism and give the working equations of the BSE approach…
Variational calculations of excited electronic states are carried out by finding saddle points on the surface that describes how the energy of the system varies as a function of the electronic degrees of freedom. This approach has several…
A specific combination of $s$-state Lamb shift $\Delta E_L(1s_{1/2}) - n^3 \Delta E_L(ns_{1/2})$ is considered. Its value is calculated both in the hydrogen and deuterium atoms for $n$ up to 12. The result inludes all correction which can…
A Hubbard-like model with SU(4) symmetry for electrons with two-fold orbital degeneracy is studied extensively. Exact solution in one dimension is derived by means of Bethe ansatz, where the sites are supposed to be occupied by at most two…
The new charmed resonance $ D_2^*(3000) $ was observed by the LHCb Collaboration in $ B $ decays. In this paper, by assigning it as four possible excited states of the $ 2^+ $ family, we use the instantaneous Bethe-Salpeter method to…
Correlated excitations in a plane circular configuration of identical atoms with parallel dipole moments are investigated. The collective energy eigenstates, their level shifts and decay rates are computed utilizing a decomposition of the…
We have completed measurements of two low-lying excited-state electric-dipole (E1) transition amplitudes in lead. Our measured reduced matrix elements of the $(6s^2 6p^2)^3P_1 \to (6s^2 6p7s)^3P_0$ transition at 368.3 nm and the 405.8 nm…
The quantum entanglement for the two electrons in the excited states of the helium-like atom/ions is investigated using the two-electron wave functions constructed by the B-spline basis. As a measure of the spatial (electron-electron…
We theoretically study an extension of the Dicke model, where the single-particle Hamiltonian has three energy levels in Lambda-configuration, i.e. the excited state is coupled to two non-degenerate ground states via two independent…
A brief review on double beta decay to excited states of daughter nuclei is given. The ECEC(ov) transision to the excited states are discussed in association with a possible enhancement of the decay rate by several orders of magnitude.
In this work we develop and implement a method for calculation of the Bethe logarithm for many-electron atoms. This quantity is required to evaluate the leading-order quantum electrodynamics correction to the energy and properties of atomic…
We discuss the epsilon-method as used in various recent QED bound-state calculations by considering mathematical model examples. Recently obtained results for higher-order self-energy binding corrections at the two-loop level are reviewed.…
We compute the energy level displacement of the excited np states of kaonic hydrogen within the quantum field theoretic and relativistic covariant model of strong low-energy bar-KN interactions suggested in EPJA21, 11 (2004). For the width…
In an atom, the interaction of a bound electron with the vacuum fluctuations of the electromagnetic field leads to complex shifts in the energy levels of the electron, with the real part of the shift corresponding to a shift in the energy…
In this paper we report calculations of potential energy curves in the $1.2 a.u.\le R\le100 a.u.$ range at Multireference Configuration Interaction (MRCI) level for doubly excited states of the H$_2$ molecule. We have focused on the $Q_2$…
We construct a novel family of solutions of the holographic superfluid model with the excited states in the probe limit. We observe that the higher excited state or larger superfluid velocity will make the scalar hair more difficult to be…
Electromagnetic transitions from deformed structures based on $\alpha$ configurations or on heavier clusters are discussed, drawing the link between multiparticle-multihole excited bands and cluster structures. Enhanced E2 and E1…
Discharge and electron-impact excitation lead to the production of metastable helium atoms in two metastable states, 2$^1$S$_0$ and 2$^3$S$_1$. However, many applications require pure beams of one of these species or at least a detailed…