Re: Parallel universe machine theory

From: Anders Sandberg (asa@nada.kth.se)
Date: Mon Jan 20 2003 - 01:15:14 MST


On Sun, Jan 19, 2003 at 05:35:18PM -0600, Damien Broderick wrote:
>
> You have a double slit interference set-up, with optional shutter on one
> slit, and evacuated photon paths from a splitter one light-day long (the
> tricky part to arrange, no doubt).
>
> You agree to open the shutter at 8 pm on the day of the next Lotto draw iff
> the winning numbers are 3, 15, 27, 28, 31 and 45.
>
> Is it the case that in those universes where this number set doesn't win,
> versions of you will all see punctate recordings on the detector, while in
> the n million fewer universes where it *does* win, you'll all see an
> interference fringe? Or does the presence of a closed shutter in most
> universes obliterate interference in *all* worlds?

Hmm, winning the lottery is such a large scale effect that decoherence
would get you. But you could do a quantum mechanical version,
"Schrödinger's fringe", where the device is in a large box and
controlled by a radioactive decay. As far as I understand things, then
you would get the fringes change as if the probability amplitude of the
potentially blocked photon was decreased (how much depends on your
setup). So for a very unlikely blocking you would get the fringes nearly
as in the typical two-slit experiment, and for a more likely blocking
they would move towards a no-fringe pattern.

> In the 1 in n million test universes where fringes do show, you'll invest in
> a ticket and be rich the next day. Better than *none* of you winning...
>
> (As I recall, the mere possibility of closing the shutter forces the
> non-interference, but maybe that gets finessed in this approach?)

You still need the photons to get to the photographic film to get
something measurable, so they will have to take the day to pass down the
beam path.

-- 
-----------------------------------------------------------------------
Anders Sandberg                                      Towards Ascension!
asa@nada.kth.se                            http://www.nada.kth.se/~asa/
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y


This archive was generated by hypermail 2.1.5 : Tue Jan 21 2003 - 17:10:21 MST