Complementarity and quantum erasure with entangled-photon states
Tedros Tsegaye, Gunnar G. Bjork, Mete Atatüre, Alexander V. Sergienko, Bahaa E. A. Saleh, Malvin Carl Teich · Physical Review A · 2000
A quantum-erasure experiment was performed on superposition states of two photons in either of two spatiotemporal modes. Symmetrical tapping of energy from the two-mode state creates a four-mode entangled state. A direct measurement of one photon in two of the modes reveals the path of the second one, thereby eliminating the possibility of observing interference between the two remaining modes. It is shown that a unitary rotation of one of the two-mode states erases the path information; as a consequence, the visibility of the other two-mode state can be resurrected.