Re: many worlds interpretation

From: Wei Dai <>
Date: Fri, 20 Feb 1998 02:47:47 -0800

On Fri, Feb 20, 1998 at 08:00:16PM +1000, Mitchell Porter wrote:
> Did you intend to use moduli squared, rather than moduli?
> What motivates this expression?

Yes, they should be squared. The motivation is that the RHS treats PSI_0
and PSI_1 as seperate worlds with no interference between them. (This is
circular, but I don't know how to explain it better.)

> In any case, in order make the condition that "there is little
> interference" precise, you will need to say something like:
> There is little interference when |LHS - RHS| < epsilon.
> In other words, you will need to introduce an arbitrary parameter
> into the definition of "world". I believe similar problems bedevil
> attempts to derive the projection postulate from decoherence.

Well the idea of independent, non-interfering worlds is an approximation
of reality to help intuition and perhaps make computation easier. The
epsilon says how close that approximation is to reality.

> There was also something unspecified: what sort of functions
> are PSI_0(r,t) and PSI_1(r,t)? For example, do you require that
> they also be solutions to the Schroedinger equation? Or are they
> just any time-varying functions at all?

I think they do have to satisfy the Schroedinger equation. Otherwise it
wouldn't make much sense to think of them as worlds.

Anyway, I am not an expert or proponent of the many-worlds interpretation.
I'm just trying to explain my admittedly shallow understanding of it, more
in hopes of being corrected than anything else. Please take what I say
with a grain of salt.
Received on Fri Feb 20 1998 - 02:48:29 PST

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