The Quantum Eraser and the Delayed Choice

The Quantum Eraser

Remember the double slit experiment? The one where you got an interference pattern? The Quantum Eraser experiment, first suggested by Martin Scully and Kai Drühl in 1982, uses such an apparatus, but with slight modifications.

The Original Double Slit
Scully and Drühl’s quantum eraser experiment

The Delayed Choice

Another interesting experiment, is the Delayed choice experiment. Suggested by John Wheeler in 1980. (Wheeler was the teacher of Richard Feynman!) This, just like the quantum eraser, modifies another apparatus, this time of the beam splitter experiment. The apparatus is given below. If you’re wondering how does one split a beam, a beam splitter is a half silvered mirror, which allows half the light to pass through, and reflects half the light.

The original beam splitter experiment
The Delayed Choice Experiment, where O is the photon detector.

The Delayed Choice Quantum Eraser

This part may confuse some reader. If you are confused, then skip to the last paragraph, but I suggest you read it, since the results are amazing.

The delayed choice quantum eraser

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