Taming the Delayed Choice Quantum Eraser. (arXiv:1707.07884v4 [quant-ph] UPDATED)

I discuss the delayed choice quantum eraser experiment (DCQE) by drawing an
analogy to a Bell-type measurement and giving a straightforward account in
standard quantum mechanics. The delayed choice quantum eraser experiment turns
out to resemble a Bell-type scenario in which the paradox's resolution is
rather trivial, and so there really is no mystery. At first glance, the
experiment suggests that measurements on one part of an entangled photon pair
(the idler) can be employed to control whether the measurement outcome of the
other part of the photon pair (the signal) produces interference fringes at a
screen after being sent through a double slit. Significantly, the choice
whether there is interference or not can be made long after the signal photon
encounters the screen. The results of the experiment have been alleged to
invoke some sort of 'backwards in time influence'. I argue that this issue can
be eliminated by taking into proper account the role of the signal photon.
Likewise, in the de Broglie-Bohm picture the particle's trajectories can be
given a well-defined description at any instant of time during the experiment.
Thus, it is again clear that there is no need to resort to any kind of
'backwards in time influence'.

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