Maximally entangled states in the Hydrogen molecule: The role of spin and correlation

TL;DR

This paper investigates the entanglement properties of the hydrogen molecule's electronic states using ab initio methods, highlighting the influence of spin and correlation effects on entanglement.

Contribution

It demonstrates that accurate correlation modeling reveals maximally entangled states in H2, linking entanglement to spin and magnetic properties.

Findings

Maximally entangled states occur in nonmagnetic (S=0) configurations.

Magnetic fields can induce entanglement in degenerate states.

Correlation effects are crucial for understanding entanglement in molecules.

Abstract

By going beyond Hubbard Hamiltonian we reflected correlation effects accurately in the wavefunctions of H2. Using ab initio e-e interaction parameters resulted maximally entangled ground and third excited states. We assigned this maximally entangled character to the nonmagnetic (S=0) property of these states and also the minimally entangled character of the first excited states to its magnetic property. By switching on a magnetic field an entangled state with Sz = 0 can be extracted from a minimally entangled degenerate magnetic state. We suggest that presence of a moderate correlated system and a non-magnetic (Sz = 0) electronic state can be two criteria for finding maximally entangled electronic states in a realistic molecular system.