What does the delayed-choice quantum eraser experiment tell us?

The delayed-choice quantum eraser experiment investigates a paradox. If a photon manifests itself as though it had come by a single path to the detector, then “common sense” (which Wheeler and others challenge) says that it must have entered the double-slit device as a particle.

Can quantum information be marked or erased by its entangled twin?

The which-path or both-path information of a quantum can be marked or erased by its entangled twin even after the registration of the quantum. Content may be subject to copyright. This paper reports a “delayed choice quantum eraser” experiment proposed by Scully and Dr¨ uhl in 1982.

How does a quantum eraser work?

A simple version of the quantum eraser can be described as follows: Rather than splitting one photon or its probability wave between two slits, the photon is subjected to a beam splitter.

Can quantum entanglement delay the determination of particlelike or wavelike behavior?

The experimental results demonstrate the possibility of delayed determination of particlelike or wavelike behavior via quantum entanglement. The which-path or both-path information of a quantum can be marked or erased by its entangled twin even after the registration of the quantum.

Why use entangled photons for quantum erasers?

Furthermore, use of entangled photons enables the design and implementation of versions of the quantum eraser that are impossible to achieve with single-photon interference, such as the delayed-choice quantum eraser, which is the topic of this article. Figure 2.

Is there a classical equivalent of the quantum eraser?

Versions of the quantum eraser using entangled photons, however, are intrinsically non-classical. Because of that, in order to avoid any possible ambiguity concerning the quantum versus classical interpretation, most experimenters have opted to use nonclassical entangled-photon light sources to demonstrate quantum erasers with no classical analog.

Can photons in the present alter events in the past?

While delayed-choice experiments have confirmed the seeming ability of measurements made on photons in the present to alter events occurring in the past, this requires a non-standard view of quantum mechanics.