Part 4/9:
To understand the delayed choice quantum eraser, it's essential first to review the double slit experiment, a simpler yet closely related setup. When quantum objects such as photons or electrons pass through two slits, they create an interference pattern indicative of wave behavior. Yet, if detectors are placed to measure which slit a particle traverses, the interference pattern vanishes, leading to an expectation-based distribution resembling that of classical particles.