  In this work, we study the quantum entanglement for doubly excited resonance
states in helium by using highly correlated Hylleraas type functions to
represent such states of the two-electron system. The doubly-excited resonance
states are determined by calculation of density of resonance states under the
framework of the stabilization method. The spatial (electron-electron orbital)
entanglement measures for the low-lying doubly excited 2s2, 2s3s, and 2p2 1Se
states are carried out. Once a resonance state wave function is obtained, the
linear entropy and von Neumann entropy for such a state are quantified using
the Schmidt-Slater decomposition method. To check the consistence, linear
entropy is also determined by solving analytically the needed four-electron
(12-dimensional) integrals.
