Computing in a Parallel Universe
Dateline: 08/19/00
By David Harris
This week's article is pretty mind-blowing so take your time and
don't worry if it seems bizarre at first - it is! To help you out,
here is a contents page through the article if you want to digest it
in bite-sized pieces and return for seconds or thirds later.
When
One Universe Just Isn't Fast Enough... - The need for speed
The
mystery of the quantum - When all else fails, use new laws of
physics
The
power of the quantum - Multi-universe multitasking
The
killer app - Cracking the world's most secure codes
Five
bits big - woohoo!
More
information
Modern computers are pretty fast. You can play amazing games with
lifelike graphics, you can simulate the behaviour of large
collections of molecules in the virtual space of a supercomputer's
universe, you can even crack the world's best secret codes. Hang on
a sec, you can't do that last one. But two out of three ain't bad,
don't you think?
Well, sometimes two out of three just isn't good enough. What
happens if you do feel the need for real speed? In that case, the
computers we have just can't handle the job. Especially in the case
of cracking secret codes and keeping information secure. (We'll get
on to that detail in the killer
app section.)
What are the ways to make a computer faster? One way is use
better chips to run your PC but that means waiting until they are
invented and the difference won't be that big anyway. You could get
a lot of chips and run them in parallel, but that is going to cost
more money and take more energy to run. You could also use up all
the spare clock cycles on people's home computers just like the
SETI@home project and the GIMPS prime hunt.
However the best approach to really intense computing
applications is to do all the various calculations you need
simultaneously with the same processor. If you don't think that a
computer can do that, think again because a new breed of computer is
on the way and they play by a completely different set of rules. You
could even say that the new types of quantum computer can do all the
calculations needed in parallel universes, thereby eliminating the
need to buy more than one processor while still using massively
parallel techniques.
This isn't science fiction. It's turning up in a physics lab near
you.
Richard Feynman received the Nobel prize for his contributions to
understanding the quantum theory of light and yet, in his landmark
paper Simulating Physics with Computers, International
Journal of Theoretical Physics, vol 21, 1982, p467, he said:
| ... we always have had (secret, secret,
close the door!)... a great deal of difficulty in
understanding the world view that quantum mechanics
represents. At least I do, because I'm an old enough man that
I haven't got to the point that this stuff is obvious to me.
Okay, I still get nervous with
it. |
When a Nobel prize winner gets nervous, you know something odd is
afoot. However, now that we know more about quantum physics and by
following Feynman's lead, we are able to use the mysteries of the
quantum to our advantage and in technologies.
Feynman thought hard about what computers could really do. One of
his major realisations was that while computers relied on classical
physics to operate, there was no way that they could perfectly
simulate quantum systems. Not wanting a little matter like the
currently accepted laws of physics as applied to computing get in
the way, his response was to propose a new regime of computing,
based on quantum mechanical principles. It is physics we know and
use regularly but had never applied to computing before.
Using new laws of physics means some pretty dramatic changes in
the way the computers will operate and we'll get on to that in a
minute.
It has taken some doing but quantum computers are now a hot
research topic around the world with a race on to build the first
functioning large scale quantum computer. This race is quite intense
with different schemes proposed and some of them already developed
on a small scale but everybody is searching for the way to put a
quantum computer on a desktop instead of in a well-equipped physics
lab.
Just this week, IBM
announced they have managed to build a quantum computer that has
a 5 bit processor and memory. In other words, it can count from 0 to
31. That might sound like a pretty feeble effort for 18 years of
research and development from the physics community but wait until
you hear what it can do and what the possibilities are when we push
that number of bits a little higher.
Next page The power of the quantum
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