X-Message-Number: 11676
Date: Wed, 05 May 1999 10:35:11 +0000
From: Damien Broderick <>
Subject: billions and trillions

I wildly proposed:

< if one had a sequential linear machine
able to operate billions or trillions of times faster than a human brain >

Thomas Donaldson commented:

< I will point out that there are physical
limits to just how fast a sequential computer can work (limits for
quantum computation or parallel computation will clearly be different,
though they also exist). >

Here's a fragment morphed from the EETimes news (pictures at 11):


Researchers at Notre Dame university have demonstrated transistorless
logic gates using quantum dots.  Demonstrated designs include AND,
NOR, and OR gates each (apparently) using four quantum dots, occupying
five nanometers square.  (It's not clear if the dots or the gates are
each occupying 5 nm square.)

Projected gate densities range up to 1 trillion (yes, 1e12) gates per
square centimeter.  Note also that the power density product for these
devices is approximately one billionth that of transitor logic, and
the power dissipated is expected to be the limiting factor in


Terafying, eh?

Damien Broderick

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