[net.physics] Bell inequalities

KATZ%USC-ISIF@sri-unix.UUCP (06/03/83)

From:  Alan R. Katz <KATZ@USC-ISIF>

In response to the message about the Bell Theorem by Roger Wells, and
an old message by Fischer@Rutgers:


The Bell inequalities DO NOT provide a way to send signals faster than light!
The theorems basically examine the consequences of having a hidden variable
theory "under" Quantum Mechanics.  The question is, suppose the universe
is really deterministic, and quantum mechanics is not the final theory
(Philisophically might be nicer, but I think determinism has bit the dust).
The Bell inequality says that:

	EITHER,
		certain experiments would give different results from
 		what quantum mechanics predicts (there has recently
		been more experiments of this type and the results
		have always been exactly as predicted by Quantum mech.).

	OR
		there exist some mysterious non-local type interactions
		which we have never directly seen which travel at greater
		than the speed of light and thus violate relativity (this
		does not mean, necessarily, that you could send signal
		faster than light.  It may be you could never "modulate"
		such signals for some reason.

	OR
		the universe is NOT deterministic and if quantum mechanics
		is not the final theory, underlying theories will also
		be non-deterministic.

The first choise seems to be ruled out by various experiments done already
(latests ones reported in Physical Review letters a few months back).  Most
physics types (myself included) would feel that the third choice is probably
true.  (Who needs a deterministic universe anyway??)

Hope this clears up a few things...


				Alan (Katz@USC-ISIF)


P.S.

	If Roger Wells, who sent the original message about this recieves
	this reply, I would be interested in knowing.  I don't know if
	replies generated on Arpanet ever make it into Usenet and have
	not gotten any evidence to that effect.


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