Complex sentence: A quantum-mechanical analog of Borromean rings, that is called a Halo state or an Efimov state in literature, was predicted by physicist Vitaly Efimov in 1970.
Split into simpler sentences: A quantum-mechanical analog of Borromean rings, that is called a Halo state or an Efimov state in literature. The latter was predicted by physicist Vitaly Efimov in 1970.