Live from "Spukhafte Fernwirkung": Yoon-Ho Kim (1999): A Delayed Choice Quantum Eraser: "This paper reports a 'delayed choice quantum eraser' experiment...
...proposed by Scully and Druhl in 1982. The experimental results demonstrated the possibility of simultaneously observing both particle-like and wave-like behavior of a quantum via quantum entanglement. The which-path or both-path information of a quantum can be erased or marked by its entangled twin even after the registration of the quantum...