Quantum entanglement for doubly-excited resonance states of the helium atom

Chien-Hao Lin, Y. K. Ho

Chien-Hao Lin, Y. K. Ho

Y. K. Ho, Chien-Hao Lin

In this work, we study the quantum entanglement for doubly excited resonance states in two-electron atomic systems such as the H - and Ps - ions and the He atom by using highly correlated Hylleraas type functions The resonance states are determined by calculation of density of resonance states with the stabilization method. The spatial (electron-electron orbital) entanglement entropies (linear and von Neumann) for the low-lying doubly excited states are quantified using the Schmidt-Slater decomposition method.

Alejandro González-Melan, Javier Madroñero

We calculate the amount of entanglement for bound and doubly excited singlet states below the second, third and fourth ionization thresholds in planar helium. Furthermore, we investigate the dynamics of entanglement in nondispersive two-electron wave packets generated by the resonant coupling of frozen planet states of helium. We show that it is possible to obtain a two-electron nondispersive wave packet for which the time-average entanglement is greater than for each of the unperturbed coupled states.

A. Mihelič, M. Žitnik, Mateja Hrast

Abstract We present an extended theoretical study of two-colour doubly resonant photoionization of helium involving two doubly excited states below the N = 2 ionization threshold. We model the effects of a strong laser coupling between the lowest 1 P o and the selected 1 S e , 1 P e and 1 D e doubly excited states on the photoelectron (photoion) yield by taking into account the spatio-temporal structure of the pulses and by considering the effects of the neighbouring resonance states. We show that the laser coupling results in a measurable modification of the line profiles and in a reduction of the photoelectron yield under resonant or near-resonant conditions.

Li-Guang Jiao, Y. K. Ho