We discover that under the fine parameters tuning the free fall of the electron in the Coulomb, magnetic and the polarized electromagnetic fields results in the existence of non-dispersing wave packets moving on triangular trajectories.
We demonstrate the existence of stable non-dispersing two-electron Trojan-like wave packets in the helium atom in combined magnetic and circularly polarized microwave fields. These packets follow circular orbits and we show that they can also exist in quantum dots. Classically the two electrons follow trajectories which resemble orbits discovered by Langmuir and which were used in attempts at a Bohr-like quantization of the helium atom. Eigenvalues of a generalized Hessian matrix are computed to investigate the classical stability of these states. Diffusion Monte Carlo simulations demonstrate the quantum stability of these two-electron wave packets in the helium atom and quantum dot helium with an impurity center.