The Ultimate, Apocalyptic Laptop nytimes.com
Meanwhile, on the entropic information front, this from today's NYT. Black holes in your laptop and everything. I would cross reference this with LRP's Message 14216900 and Message 14216989, but as a longtime Microsoft follower, this particular interpretation is more comprehensible.
Some people may be convinced that they already have a black hole
laptop, imploding at the worst possible moments and irretrievably
swallowing data. Owning the real thing would surely be even worse.
But, let's put that in context:
Now that he had put an upper limit on speed, Dr. Lloyd wanted to see
how big he could make the machine's memory — how many bits of
information could be stored and manipulated at those blazing speeds.
Every atom or even every electron could be used to register a 1 or a 0,
depending on which way it was spinning. But to store the maximum
amount of information, the little processors would have to be free to
assume as many different states as possible. At intense energies,
information might be encoded not just by the spin of a particle but also by
the speed and direction in which it was moving inside the machine.
"In order to take full advantage of the memory space available, the
ultimate laptop must turn all its matter into energy," Dr. Lloyd said. "A
typical state of the ultimate laptop's memory looks like a thermonuclear
explosion or a little piece of the Big Bang! Clearly, packaging issues
alone make it unlikely that this limit can be obtained, even setting aside
the difficulties of stability and control."
An object like this, so packed with energy that its particles are as free as
they can possibly be, is said to be in a state of maximum entropy. Though
more commonly thought of as a measure of disorder — a vaporized
laptop being less orderly than one at room temperature — entropy is also
intimately related to information. The higher an object's entropy, the
greater the number of different states its particles can assume, and the
greater the amount of information it can store.
For the ultimate laptop, the maximum entropy corresponds to an
information capacity of about 2.13 x 1031 bits — a billion trillion times
more than today's laptops.
Achieving so vast a memory might not be as unrealistic as it sounds. In a
kilogram of matter there are approximately 1025 atomic nuclei, each of
which could store a bit without vaporizing the entire mass. "One can get
quite close to the ultimate physical limit of memory without having to
resort to thermonuclear explosions," Dr. Lloyd said.
Until this point, Dr. Lloyd had been constraining himself to a laptop with
a volume of one liter. If he could make it even smaller, he knew, he could
pack the kilogram of particle-size components even tighter, speeding up
the information flow and shortening the time it takes to do long,
step-by-step calculations. He would be sacrificing memory (there would
be less room to store information) for speed.
So in the final act of his thought experiment, he programmed the ultimate
laptop to solve a formidable problem (cracking a secret code or
something like that) and imagined it shrinking and shrinking — to the size
of a wallet, then a credit card, then a postage stamp. Smaller and smaller
until its radius is a mere centimeter (10-2 meters), then a millionth of a
meter (10-6), then a billionth (10-9).
When the laptop has shrunk to 10-27 meters (a billionth the size of a
proton), it crosses what is called the Schwarzschild radius: So much mass
is packed into so little space that the whole thing collapses, sucking itself
into a tiny black hole.
Some people may be convinced that they already have a black hole
laptop, imploding at the worst possible moments and irretrievably
swallowing data. Owning the real thing would surely be even worse.
According to some theories, however, information thrown down a black
hole does not disappear, but is displayed on the hole's surface. Each
pixel of this screen would occupy one square Planck length, 10-35 by
10-35 square meters, the smallest area conceivable by the laws of
physics.
Some theorists, in fact, believe that the information about everything that
falls into any black hole is projected in this manner — that each one of
these sinkholes is, in a sense, processing information. Viewed this way,
exercises like Dr. Lloyd's could have implications for physics and
cosmology.
"I would hope that the long-term consequence of this work is not building
a black hole computer, which would be a dangerous thing to do," Dr.
Lloyd said, "but seeing whether we can understand how nature itself
processes information."
If particles trade bits of data as readily as they trade energy, then the
universe itself is the ultimate computer. And physics is a matter of
deciphering its program.
Cheers, Dan. |
