Saturday, December 31, 2016

Delayed Choice Quantum Eraser

This is the greatest bit of scientific hokum I've run across in quite a while.  The delayed choice quantum eraser experiments are, to me, intensely amusing bits of scientific theater and sleight-of-hand.

The problem is, the scientists doing and reviewing these experiments don't get the joke.  They think it's real.

To review, a delayed choice quantum eraser involves using a clever arrangement of beam splitters and mirrors to identify (or not) which path a photon travels through, well, let's call it a maze.  They then claim than when we human's have knowledge of which path the photon took, it acts like a particle, but when we humans don't know which path it took, it acts like a wave.  Oh, and in some experiments, there appears to be a backwards in time flow of information from one part of the experiment to another.

This all has caused great consternation and debate in scientific circles.  Which just goes to show that most scientists aren't all that smart.

They all ignore one very simple thing:  scientific instruments aren't Platonian ideal instruments.  They are physical things.  To be specific, beam splitters work by selecting some photons to transmit, and some to select.  This is a mechanical action.  This selection is what seems to cause the interference patterns in these experiments.  That's it.  All these experiments serve simply to show that, by golly, the beam splitter selectively split the beam into two parts.

They completely overlook the physical nature of the half-silvered mirror.  It, by its nature and design, selects some photons for one path or another (even though the wave divides and travels both).  The specific properties of each photon determines which path it is more likely to travel.  These paths are thus deterministic but unknowable.  Similarly configured photons will follow similar paths.  And thus, the apparent interference pattern emerges from the simple act of selecting photons by the beam splitters.

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