A simple quantum eraser

Jean-Louis Basdevant, Jean Dalibard

Robert Garisto, Lucién Hardy

We define a new measurement of entanglement, the entanglement of projection, and find that it is natural to write the entanglements of formation and assistance in terms of it. Our measure allows us to describe a new class of quantum erasers which restore entanglement rather than just interference. Such erasers can be implemented with simple quantum computer components. We propose realistic optical versions of these erasers.

H. Kobayashi, Shuhei Tamate, Toshihiro Nakanishi +2 more

We introduce a simple experiment involving a double-slit interferometer by which one can learn basic concepts of quantum interference such as which-path marking, quantum erasers, and geometric phases. Each of them exhibits seemingly mysterious phenomena in quantum physics. In our experiment, we use the double-slit interference of visible light with the polarization as an internal state to demonstrate the disappearance of fringes by which-path marking, recovery of interference using quantum erasers, and the rapid shifting of the fringe pattern induced by the geometric phase. We also present a simple theoretical analysis of an interferometer with an internal state.

Marco Di Mauro, L M Gratton, Pasquale Onorato +1 more

We describe a simple experimental apparatus which allows the quantitative study of the classical analog of a quantum eraser. The apparatus consists of a laser diode, a thin wire, two polarizers providing the which-way information, and a third polarizer which erases that information. The experimental results are analyzed with the aid of a digital camera and the Tracker application, and are compared with a novel classical computation of the interference patterns, which is presented as well.

Hans Christian von Baeyer