Parallel
universes

how we could use them
by Marcus Loane
5^{th} November 2010
A possible use for multiple parallel universes.
If you have read anything on
quantum theory you will be aware of the "many worlds" interpretation
of the weird results of some experiments (eg. the
double slit experiment). This suggests that there is a branching off of
universes so that everything that can happen will happen in other universes.
A simple quantum computer has
been built which does computations in the other universes. A quantum computer,
rather than processing instructions one after the other, can process multiple
instructions in parallel (universes) before coming out with the answer. Quantum
computers are very simple at the moment and can handle only 10 to 15 bits of
information at the time of writing.
Fast forward to the future and
perhaps we will have developed quantum computers that are much more powerful.
We could reach a point where our quantum computer is able to execute a
computation that is larger than there are particles in our universe
(approximately one followed by 85 zeroes) and vastly larger than there are
nanoseconds in the entire age of the universe to date. So where did the
computation get done? There is not enough time and there are not enough
particles in our universe for it to have used our universe alone. We may have
to conclude that the parallel universes are real and not just an interpretation
 we will have accessed them to do real work.
For example Shor's algorithm for quantum computers (Peter Shor 1995) will allow extremely quick factoring of large
numbers if we can build a quantum computer to execute it. A classical computer
can be estimated at taking 10 million billion billion
years (a million billion times longer than the age of the universe) to factor a
1000 digit number, whereas a quantum computer would take around 20 minutes.
That could be a stunning demonstration of the reality of parallel universes.

Marcus Loane
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