X-Message-Number: 18450
Date: Thu, 31 Jan 2002 14:42:17 +0100
From: Henri Kluytmans <>
Subject: simulation, can 813 coupled qubits simulate the universe

Yvan Bozzonetti wrote :

>To simulate the Universe (ten billion light years in radius for ten billion 
>years) you need 10^244 Planck's cubes ( One Planck's unit for each dimension 
>in space and time). This could be run by a quantum computer with a 813 bits 
>word in a single computation cycle, something as a billionth of a second. 

Ehhh ???

A quantum computer of 813 coupled qubits can only store a superposition 
of all 2^813 possible combinations of 813 normal bits. And it can perform 
operations on all those 2^813 combinations in only one single operational 

But it can not store or operate on 10^244 (~= 2^813) bits! The possible 
combinations of that number of bits are 2^(10^244) !!! 

Furthermore, does a Planck cube contain only 1 bit of information ?

>This illustrates the potential power of quantum computers and the 
>effect of state superposition in quantum mechanics.

Sorry, but this seems to be a huge misconception about the 
potential power of quantum computers.


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