Perturbation Theory and Atomic Resonances Since Schrödinger’s Time

Resonances and convergence of perturbation theory for N-body atomic systems in external AC-electric field

It is proved that the action of a weak external AC-electric field of frequency 03C9/203C0 shifts all non-threshold bound states and resonances of any N-body atomic system into resonances of the AC-Lo Surdo-Stark effect, defined as eigenvalues of the complex scaled Floquet Hamiltonian. In marked contrast with the cc~ = 0, DC-field case, the Rayleigh-Schrodinger perturbation expansion converges t...

Two- and Three-Photon Partial Photoionization Cross Sections of Li+, Ne8+ and Ar16+ under XUV Radiation

In this work, we present the photon energy dependence of the twoand three-photon cross sections of the two-electron Li+, Ne8+ and Ar16+ ions, following photoionization from their ground state. The expressions for the cross sections are based on the lowest-order (non-vanishing) perturbation theory for the electric field, while the calculations are made with the use of an ab initio configuration ...

N+CPT clock resonance

In a typical compact atomic time standard a current modulated semiconductor laser is used to create the optical fields that interrogate the atomic hyperfine transition. A pair of optical sidebands created by modulating the diode laser become the coherent population trapping (CPT) fields. At the same time, other pairs of optical sidebands may contribute to other multiphoton resonances, such as t...

Resonances in n-body quantum systems with dilatation analytic potentials and the foundations of time-dependent perturbation theory*

A Rational Approach to the Resonance Region

The Chiral Lagrangian organizes the physics of the strong interactions at low energy as an expansion in powers of momentum and masses of the lightest pseudoscalar fields. Since all the heavier states of QCD are integrated out, their physics is encoded in a set of Low Energy Constants (LECs). These LECs are indispensable to make definite predictions in Chiral Perturbation Theory. However, while ...