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From: helmut@cosy.sbg.ac.at (Helmut Mayer)
Subject: Re: Random Number Generator Effects
Message-ID: <D972ov.E4u@wst.edvz.sbg.ac.at>
Sender: news@wst.edvz.sbg.ac.at (USENET News System)
Reply-To: helmut@cosy.sbg.ac.at
Organization: University of Salzburg / Austria
References: <3prg6q$j5r@ixnews3.ix.netcom.com>
Date: Fri, 26 May 1995 16:48:31 GMT
Lines: 39

Jonah Thomas writes

# What people want for a rng for digital machines, is to be able to read off a 
# series of 1's and 0's that aren't correlated to anything, that each have 
# probability one half.  Is there a body of theory built up that explains just  
how 
# resistors make their noise?

Yes. In classical terms the theory of statistical mechanics can be transponed  
to electrons. That's why we speak of "electron gas" in a  
metal.(Maxwell-Boltzmann-Distribution). Copper (not actually used as resistor  
material, but it also shows resistance above a very low (some Kelvin)  
temperature) has a free electron density of 1.15*10^20 per mm^3. All these  
electrons move randomly due to temperature (in sum there is no electric flow  
without an external electric field).

# If the theory isn't fully developed about resistors, then 
# I'd strongly prefer a hardware device where people at least believe they know 
# what's going on.

Exactly because it's fully developed, you don't know what's going on..;-) i.e.  
all physical parameters are averaged parameters with a certain probability  
distribution, but you can't say what happens with a single (group of)  
electron(s) and you never will, as long as nobody proves the  
Heisenberg-inequality to be wrong.
So I understand your and others concern about the repeatability of PRNG, but in  
practical terms a good (again, what is good?) PRNG doesn't have to be  
repeatable but hopefully very random.

Best regards,

Helmut
---
Helmut A. Mayer, University of Salzburg, Department of Computer Science
*** Member of siGis ***
Jakob-Haringer-Strasse 2, A-5020 Salzburg, AUSTRIA
Tel.: +43-662-8044-6315  Fax: +43-662-8044-611
"...All I want is PEACE and LOVE on this planet, aint how that GOD planned  
it?..." - Chuck D.
