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Date: Thu, 07 Aug 1997 21:12:15 -0400 From: John Young <jya@pipeline.com> Subject: Shor's Algorithms: Mad, Bad and Dangerous

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From a WSJ nook review today of "The Fabirc of Reality," by David Deutsch (Allan lane, 390 pp., $29.95):

Using something called "Shor's algorithm," a quantum computer can factor giant numbers and thereby break secret codes that no conventional computer could touch.

The only way it could do this, Mr Deutsch argues, is by distributing its operations over many parallel universes. "To those who cling to a single-universe world-view," he writes with evident asperity," I issue the challenge: *explain how Shor's algorithms works.*"

From an existential perspective it is simply another way of viewing the Hamiltonian of the wave equation. In short the Many World theory says that all possible outcomes are available in parallel, you only get to experience one of them. The standard model says the Hamiltonian collapses from its n-element state to a single valued state at the time of measurement (ie the system is in no state unless measured). Which was Schroedingers explicit complaint, in his cat model the question he was asking (that gets dropped by modern physicist because it is so subversive to the Standard Model) is "Doesn't the cat know what state it is in?". The implicit (and never stated) assumption in the Standard Model is that a particle's state is defined by

The Many Worlds Hypothesis was developed by David Bohm and is an alternate way of looking at the Uncertaintly Principle, which gets its origin from the collapse of wave functions used to describe the potential states of a wave. The advantage of using a Many Worlds Hypothesis is that it allows you to do away with Bohms, Schroedinger, Einstein, etc. objections to the standard model, God playing with dice. the particles and their interactions that surround it AND the particle is comletely unaware of it. Which brings questions like "How does the electron know to be in the S1 orbital if it doesn't have any way of knowing its energy state?". This is especialy problematic since a base assumption is that the only way to effect an electron is through a photon. A good extension is consider the insanity of the Moon disappearing when you aren't looking at it. Look at the Moon and the tides appear, look away from the Moon and the tides go away...

Combining the many-universes notion with quantum probablity,

You can't combine them, the whole point of the Many Worlds theory is to explicity eliminate quantum probability and bring the mechanism into the deterministic model used at higher levels of scale (ie Newtonian Mechanics). The goal is to build a system that is consistent across questions of scale.

and adding elements of Darwinism and Karl Popper's theory of knowledge, Mr. Deutsch apsires to nothing less than a complete understanding of "the fabric of reality." Arrogant in tone and marred by leaps of logic, his book nonetheless bristles with subversive insights about virutal reality, time travel, mathematical certainty and free will. Intellectually speaking, Mr. Deutsch is mad, bad and dangerous to know.

Sounds like a bunch of wishfull thinking and serious misunderstanding of Bohm, Schroedinger, etc.'s work. ____________________________________________________________________ | | | Participation requires more than just bitching! | | | | _____ The Armadillo Group | | ,::////;::-. Austin, Tx. USA | | /:'///// ``::>/|/ http:// www.ssz.com/ | | .', |||| `/( e\ | | -====~~mm-'`-```-mm --'- Jim Choate | | ravage@ssz.com | | 512-451-7087 | |____________________________________________________________________|