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Topic: Simple random number generator?
Replies: 24   Last Post: Jan 7, 2013 10:52 AM

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David Bernier

Posts: 3,892
Registered: 12/13/04
Re: Simple random number generator?
Posted: Dec 20, 2012 8:06 PM
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On 12/20/2012 03:15 AM, Michael Press wrote:
> In article<>,
> Phil Carmody<> wrote:

>> Michael Press<> writes:
>>> In article
>>> <>,
>>> Ben Bacarisse<> wrote:

>>>> Good quality, hardware-generated random number sequences (if our current
>>>> understanding of quantum effects is correct) are random in a different
>>>> way to the digits of pi. It helps if the terminology is be able to
>>>> distinguish between them.

>>> I do not see how quantum effects can be used to generate
>>> random sequences. Coherent systems are stable and highly,
>>> if not perfectly, predictable.
>>> Hardware generated random sequences usually read Schottky
>>> noise off some device (a sound card in a computer) and use
>>> that. This can be modeled using entirely classical physics.

>> Are you sure? Shottky noise is white noise, and thus is
>> indistinguishable from thermal (Johnson-Nyquist) noise.
>> So you can statistically model it the same way, but that
>> doesn't mean it's actually caused by classical mechanics.
>> I can't find any references to Shottky noise that don't
>> mention some quantum effect.

> _What_ quantum effect? So far I am the only one who
> does not gloss over this question. That `quantum
> effects' are involved does not imply that they
> beget stochastic effects.
> Experiment and analysis of time series show that
> radioactive decay has an unexplained component. Further
> this unexplained component is no more complicated or
> less simple than diffusion across a membrane. Bluntly,
> equivalent to deflation of a bicycle tire.
> By `quantum' I read `wave theory of matter'. The
> original Bohr theory is as good as we have for what
> might actually be happening.
> (Personally I do not adhere to any interpretation used
> to psychologically make the experiments more palatable;
> preferring to confront as best my faculties allow the
> raw facts.)

We tend to take "measurement" as an objective practice.
But I think there's a subtle interplay between theory
and practice or experimental physics.

Measuring is a phenomenon involving physicists, their
apparatus and what they're observing. (maybe? )

In practice, a sophisticated measurement relies on a long
chain of observations, calculations and assumptions on
what's negligible. These days, it will likely invoke
electro-magnetic theory, since digital measurements
are so common .

The statistics of quantum mechanics has to do with
"observed things", the result of measurement in the
wider sense (approximately).

What is "measuring" in physics, in a once-and-for-all


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