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The second (unphysical) critical charge in the three-body quantum Coulomb system of a nucleus of positive charge and mass , and two electrons, predicted by Stillinger has been calculated to be equal to and for infinite and finite (proton) mass , respectively. It is shown that in both cases, the ground state energy (analytically continued beyond the first critical charge , for which the ionization energy vanishes, to ) has a square-root branch point with exponent 3/2 at in the complex -plane. Based on analytic continuation, the second, excited, spin-singlet bound state of negative hydrogen ion H is predicted to be at −0.51554 a.u. (−0.51531 a.u. for the finite proton mass ). The first critical charge is found accurately for a finite proton mass in the Lagrange mesh method, . [ABSTRACT FROM AUTHOR]

Thermodynamics of trapped charged ideal spin-1 bosons confined in a magnetic field are investigated within semi-classical approximation and truncated-summation approach. It is shown that the critical temperature increases slightly at the first, and then decreases slowly with increasing external magnetic field. Charged spin-1 Bose gases present a crossover from diamagnetism to paramagnetism as the spin factor increases. Charged spin-1 Bose gases exhibit distinct thermodynamic behaviors from the spinless case. [ABSTRACT FROM AUTHOR]

The ASACUSA collaboration of CERN has recently carried out two-photon laser spectroscopy of antiprotonic helium atoms. Some nonlinear two-photon transitions of the antiproton at the deep UV wavelengths λ = 139.8-197.0 were excited by irradiating the atom with two counterpropagating laser beams. This reduced the thermal Doppler broadening in the observed spectral lines. Three transition frequencies were thus determined with fractional precisions of 2.3-5 parts in 109. By comparing the results with three-body quantum electrodynamics calculations, the antiproton-to-electron mass ratio was derived as 1836.1526736(23). In this paper, we briefly review these recent experimental results. [ABSTRACT FROM AUTHOR]