Quantum entanglement for two electrons in the excited states of helium-like systems

Abstract

The quantum entanglement for the two electrons in the excited states of the helium-like atom/ions is investigated using the two-electron wave functions constructed by the B-spline basis. As a measure of the spatial (electron-electron orbital) entanglement, the von Neumann entropy and linear entropy of the reduced density matrix are calculated for the 1s2s 1,3S excited states for systems with some selected Z values from Z=2 to Z=100. Results for the helium atom are compared with other available calculations. We have also investigated the entropies for these excited states when the nucleus charge is reduced from Z=2 to Z=1. At such a critical charge, all the singly-excited states of this system become unbound, and the linear entropies and the von Neumann entropies for the excited states are approaching 1/2 and 1, respectively, the limits for the entropies when one electron is bound to the nucleus, and the other being free.

Final version to be published in Canadian Journal of Physics; more references added; more tables added; discussion expanded

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Cited by in corpus (6)

• Entanglement in indistinguishable particle systems
• Shannon Information Entropy in Position Space for Two-Electron Atomic Systems
• Entanglement entropies in the ground states of helium-like atoms
• Two-orbital quantum discord in fermion systems
• Quantification of Entanglement Entropies for Doubly Excited States in Helium
• Bipartite correlations in quantum resonance states