Related papers: Electric-field induced helium-helium resonances
Motivated by the particle acceleration problem in pulsars, we numerically investigate electrostatic instability of electron-positron pairs injected in an external electric field. The electric field is expected to be so strong that we cannot…
Recent results on searches for signals of physics beyond Standard Model at the ep collider HERA are reviewed. Limits obtained for contact interaction models, large extra dimensions and finite quark radius are presented. Searches for…
Precision atomic spectroscopy provides a sensitive probe of physics beyond the Standard Model. A recently reported $9\sigma$ theory-experiment discrepancy in the ionization energy of metastable helium has motivated the hypothesis of a new…
Ground state ionization potential of the He^4 atom is evaluated to be 5 945 204 221 (42) MHz. Along with lower order contributions, this result includes all effects of the relative orders alpha^4, alpha^3*m_e/m_alpha and…
Motivated by recent HAL QCD simulations of the $\phi N$ interaction in the $^4S_{3/2}$ channel and its modification in the $^2S_{1/2}$ channel, we develop a first-principles few-body framework that embeds these potentials into…
The impact of an edge radial electric field on the particle orbits and the orbital spectrum in an axisymmetric toroidal magnetic equilibrium is investigated using a guiding center canonical formalism. Poloidal and bounce/transit-averaged…
We investigate the effect of dynamic electron correlation on high-harmonic generation in helium atoms using intense visible light (\lambda=390nm). Two complementary approaches are used which account for correlation in an approximate manner:…
Measurements of the t-t and p-t coincidence events in the $^3$H ($\alpha$, ttp) reaction have been obtained at $E_\alpha$ incident energy of 67.2 MeV. Various appropriate angular configurations of detectors were chosen in order to observe…
The nonrelativistic energies of the homonuclear ion T$_2^+$ are calculated for the ground state using the Lagrange-mesh method as was done for the isotopomers H$_2^+$ and D$_2^+$ ({\it J. Phys. B: At. Mol. Opt. Phys.} {\bf 45} 065101 and…
We present an exhaustive analysis of the light-induced frequency shifts of the photoassociation lines of ultracold metastable 4He* atoms in a magnetic trap. The measurements of the shifts of several vibrational levels bound in the purely…
We present an experimental and theoretical study of the emission and absorption spectra of the Ba$^{+}$ ions and Ba$^{+\ast}$He excimer quasimolecules in the cryogenic Ba--He plasma. We observe several new spectral features in the emission…
Both isoscalar and isovector spin-dipole excitations of $^4$He are studied using realistic nuclear forces in the complex scaling method. The ground state of $^4$He and discretized continuum states with $J^{\pi}=0^-, 1^-, 2^-$ for A=4 nuclei…
We investigate multi-electron effects in strong-field ionization of Helium using a semi-classical model that, unlike other commonly used theoretical approaches, takes into account electron-electron correlation. Our approach has an…
In this paper we propose five different modifications of the hard sphere potential for the modeling a short-range repulsion and the calculation of thermodynamic and transport properties of liquid He4. We calculate the potential energy, the…
Elastic electron-helium-3 scattering is studied in the relativistic impulse approximation. The amplitudes for the three-nucleon system are obtained by solving the relativistic generalization of the Faddeev equations with a separable…
We study the spectra and response of two electrons moving on a surface of a sphere and interacting via harmonic potential, to external static and laser fields. The spectrum of such system law is analysed in the light of varying coupling…
Electric-field noise from the surfaces of ion-trap electrodes couples to the ion's charge causing heating of the ion's motional modes. This heating limits the fidelity of quantum gates implemented in quantum information processing…
We theoretically study slow collisions of NH$_3$ molecules with He atoms, where we focus in particular on the observation of scattering resonances. We calculate state-to-state integral and differential cross sections for collision energies…
We present recent results for neutron-rich Helium isotopes obtained from the hyperspherical harmonics method. Ground-state properties, like the binding energy and the point-proton radius are shown for the two-neutron halo nucleus 6He using…
We present the results of new experiments on the observation of the electric response of superfluid helium (He II) at the excitation of second-sound waves in it. We used an acoustic resonator with dielectric case, in which the measurements…