Quantum Eraser (Poster & Demo)

C M Chandrashekhar | QOQI Lab

""A Quantum Eraser using a Mach-Zehnder Interferometer demonstrates how the availability of which-path information affects interference. A photon entering the interferometer splits at the first beam splitter, taking two possible paths before recombining at the second beam splitter. When the paths remain indistinguishable, an interference pattern forms at the detectors. However, introducing a which-path marker, such as polarization, destroys the interference by making the paths distinguishable. If a quantum eraser, like a polarizer or additional beam splitter, removes this distinguishing information, the interference pattern reappears, showing that the mere potential to obtain which-path information determines the outcome, not just the physical setup."