----- Original Message ----- 
From: "Jesse Mazer" <[EMAIL PROTECTED]>
Sent: Thursday, August 12, 2004 4:28 PM
Subject: Re: Quantum Rebel

> Is Unruh saying that in figure 2 without the absorber, the amplitude of a
> photon travelling along path 4 is zero, but with the absorber in place,
> there is some nonzero amplitude for a photon to travel along path 4 but
> be scattered into the "wrong" detector? If he's not suggesting the
> possibility the absorber will scatter photons without absorbing them is
> relevant here, then I wouldn't think he'd say the possibility the wires
> scatter photons without absorbing them is relevant to Afshar's experiment.
> When you say "the mathematics of quantum mechanics assures this", did you
> actually do a calculation of the effects of scattering in Afshar's
> experiment?
> Jesse Mazer
    Until the photon reaches the detector, the mathematics of quantum
mechanics are the essentially the same as that of a classical wave, but are
not the same as the 'ray tracing' approximation. Without the wires there,
according to quantum meachanics, the photon will travel like a wave, passing
through both initial slits, forming a diffraction pattern, and eventually
producing a superposition of two different states corresponding to the two
detectors having been hit. This superposition is unstable and decoheres
(thats what makes them 'detectors'; if instead you had two new slits, you
could leave the photon to perform more interference shenanigans). The
presence of the wires shows that the 'state vector collapse' occurs after
the photon reaches the detectors, not at the slits, which is obvious with a
flat screen as the detector, but the two detectors positioned at the
geometrically significant positions creates the illusion of each photon
having traced a single ray-like path. Essentially Ashfar's experiment
involves fooling himself (and perhaps a few others) with a new single-path
photon thoery, then undermning the new theory, whcih was not quantum

--Chris Collins

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