Austrian physicist Erwin Schrödinger (1887-1961), one of the giants of contemporary science, considered entanglement the most interesting property in quantum mechanics. In his view, it was this phenomenon that truly distinguished the quantum world from the classical world. Entanglement occurs when groups of particles or waves are created or interact in such a way that the quantum state of each particle or wave cannot be described independently of the others, however far apart they are. Experiments performed at the University of São Paulo’s Physics Institute (IF-USP) in Brazil have succeeded in entangling six light waves generated by a simple laser light source known as an optical parametric oscillator.