Simultaneous Excitation Processes Research Articles

Atoms in separated resonators can jointly absorb a single photon

The coherent nonlinear process where a single photon simultaneously excites two or more two-level systems (qubits) in a single-mode resonator has recently been theoretically predicted. Here we explore the case where the two qubits are placed in different resonators in an array of two or three weakly coupled resonators. Investigating different setups and excitation schemes, we show that this process can still occur with a probability approaching one under specific conditions. The obtained results provide interesting insights into subtle causality issues underlying the simultaneous excitation processes of qubits placed in different resonators.

Angular distribution of photons for the simultaneous excitation and ionization of He-like uranium ions in relativistic ion-atom collisions

Simultaneous ionization and excitation processes are studied for initially He-like uranium ions in collisions with xenon gaseous targets at relativistic energy, $220\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}/u$. The virtue of investigating the process of simultaneous excitation and ionization is that one electron ends up in the continuum, while the other electron ends up in a hydrogen-like final state. Experimentally, this process can be identified by observing the radiative decay of the excited levels in coincidence with ions that lost one electron (U${}^{91+}$). In particular, owing to the large fine-structure splitting of H-like U, the angular distribution of photons for the simultaneous ionization and excitation into the different total angular momentum $j=1/2$ and $j=3/2$ states of the L shell is determined directly from the obser-ved yields of Ly${}_{\ensuremath{\alpha}1}$ and Ly${}_{\ensuremath{\alpha}2}$ radiation at various observation angles. The experimental data show a progress for the dependence of the alignment on the collision impact parameter. It is shown that the current results confirm the theoretical predictions based on the independent-particle approximation and first-order perturbation, for which the simultaneous ionization and excitation processes occur at small impact parameter.

Excitation of transitions of singly charged ytterbium ions terminating on levels 4f 13(2 F°7/2)5d6s(3 D) 3[L 2

The excitation of transitions of singly charged ytterbium ions terminating on odd levels 4 f 13 () 5 d 6 s ( 3 D ) 3 ( L 2 )° is experimentally studied. The generation of excited ytterbium ions occurs as the process of simultaneous excitation and ionization under single electron-atom collisions. Eighty five excitation cross sections are measured at an electron energy of 50 eV. Fifteen optical excitation functions are recorded with the energy of exciting electrons varying from zero to 200 eV.

Simultaneous excitation and ionization of He-like uranium ions in relativistic collisions with gaseous targets

The process of simultaneous excitation and ionization is investigated for He-like uranium $({\mathrm{U}}^{90+})$ ions colliding with Ar, Kr, and Xe targets at an incident energy of 223.2 MeV/u. The two-electron transitions, where one of the ground-state electrons is promoted into the continuum and the other into the L-subshell states of the projectile, are identified by the coincident observation of U Lyman-series radiation and ${\mathrm{U}}^{91+}$ ions. The experimental cross sections are compared to relativistic calculations based on the independent particle approximation and first-order perturbation theory. It is shown, that simultaneous excitation-ionization occurs preferably at small impact parameters, for which the excitation process is dominated by the monopole part of the interaction potential and the perturbation potential is largest. Good agreement is found between experimental data and calculations for the Ar target. For heavier targets the experimental results are generally smaller than predicted pointing to the invalidity of the first-order perturbation theory in this energy--target atomic number domain.

Stability of Cylindrical Shells under Random Excitation

A Lyapunov-type approach is used in the investigation, and the formulation of the problem is perfectly general in terms of the dynamic system input-output statistical correlation as well as the degree of stochastic interdependency of the excitation processes. The dynamic motion of the system considered can be described by a Hill-type equation with two stochastic parameters. Sufficient conditions are developed to ensure mean-square global stability in terms of statistical parameters of the excitation processes and physical system parameters. Stochastic convergence and mean-square global stability are defined and examined. The shell is considered to be subjected to simultaneous axial and radial stochastic loadings. The results obtained are more general than those formerly available since the present results permit any degree of system input-output correlation as well as any degree of stochastic interdependency between the simultaneous excitation processes. In addition, the techniques utilized in this analysis are capable of being extended to systems involving more than two simultaneous excitations.