Eur. Phys. J. D (2013) 67: 83
https://doi.org/10.1140/epjd/e2013-40080-y

Regular Article

Entanglement in helium

¹ CNISM and Center for Nonlinear and Complex Systems, Università degli Studi dell’Insubria, Via Valleggio 11, 22100 Como, Italy
² Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, 20133 Milano, Italy
³ Department of Information Technologies, University of Milan, Via Bramante 65, 26013 Crema, Italy
⁴ Department of Physics, University of Milan, Via Celoria 16, 20133 Milano, Italy

^a e-mail: giuliano.benenti@uninsubria.it

Received: 12 September 2012
Received in final form: 12 February 2013
Published online: 30 April 2013

Abstract

Using a configuration-interaction variational method, we accurately compute the reduced, single-electron von Neumann and linear entropy for several low-energy, singlet and triplet eigenstates of helium atom. We estimate the amount of electron-electron orbital entanglement for such eigenstates and show that it decays with energy.