Do you have an example of a truly random phenomenon?

[Baluncore]

I believe the important thing is to avoid small numbers of quantum events. To do that look at the running average of a trillion events, where the statistical profile of the population swamps the individuals many times over.

 

[George Keeling]

Isn't Norton's dome an example of a classical system that is indeterminate (i.e. truly random)? It's a bit like

You have a device that tosses the needle so that at least sometimes that needle lands balanced on its tip.

In it a perfect ball balances on something that looks like a perfect pointy helmet (imperfectly drawn below). It either stays there for ever (like what somebody said about the needle) or it suddenly starts to roll down at a random time in a random direction. It something to do with being able to propel the ball up the helmet at such a well chosen velocity that it exactly stops at the top. And the equations are reversible.

people dispute this!

 

[Baluncore]

The problem with a single event is that it may not happen, the random generator may suffer from a halting problem. It is also predictable.
The advantage of band-limited noise, with zero crossings, is that there will always be a stream of random bits, even though they will arrive at an irregular rate.

 

[BWV]

Will an AFC or NFC team win the 2030 Super Bowl?

no possible knowledge today could predict that outcome

 

[sysprog]

Will an AFC or NFC team win the 2030 Super Bowl?

no possible knowledge today could predict that outcome

Any Given Sunday . . .

 

[sophiecentaur]

I take two of those quite independent Q free signals and band-pass limit them into two wide but separate parts of the spectrum. They cannot correlate, because their spectra share no common frequency, (the product of their Fourier transforms will always be zero).

The cross correlation of many maths functions can be zero. That doesn't mean they are random.

You'd have to explain how you are taking the Q out of your original processes. It's true to say that you can apply an appropriate filter that can 'reduce' the randomness - for instance if you put a resonator with very narrow passband (I avoided punning with "Q factor" lol) then you can be pretty certain that the volts across it will be very near what you'd expect from an ideal oscillator but the phase of what you observe will still be random ( a very low frequency phase mod) and due to Q effects in your noise source.

I think your problem is that you are ignoring the fact that deterministic processes can't be random because they follow the axioms of Mathematics. You want random out so you need random in. Adding extra steps doesn't take that away.
"Near enough' Random is much easier to achieve with a big enough computer nowadays. But you need to specify the degree of randomness to decide if it really is good enough. The processes that are used in encryption and e-currencies may be cracked one day.
Bringing chaos into this is no help because, if you actually know the initial conditions in a chaotic model (i.e. you put the numbers into a simulation) you know the result. For the outcome to be random, you need a real situation and that will be subject to QM.
An electronic random generator will be random because somewhere inside it, there is the probability of a Q mechanical process crossing some threshold at random and being interpreted by the 'observer' / Ernie machine as a discrete value.

Your example of a lava lamp being "way more" deterministic is a bit like virginity. You're either a virgin or not and your acknowledged Quantum component, way back along the track, makes it still truly random.

 

[Filip Larsen]

Your example of a lava lamp being "way more" deterministic is a bit like virginity. You're either a virgin or not and your acknowledged Quantum component, way back along the track, makes it still truly random.

I mentioned lava lamps and my point still stands, namely that the dynamics of a lava lamp is classical deterministic, whereas the Josephson junctions is not. If we want to search for a "truly random classical system" (however vain we kind of all agree such a search will be) we surely are better off starting with a classical system that exhibit unpredictable behavior (that may appear random due to lack of knowledge of the initial conditions), than with a system that has a dynamics that "directly" taps into quantum events. The lava lamp (or similar system) can be modeled with a fully deterministic (mathematical) model, whereas a model of the junctions need a stochastic process to capture the same behavior.

Norton's Dome, as mentioned earlier in the discussion, is perhaps a very good example of such an interesting system with fully deterministic dynamics and symmetry breaking (even in finite time which I hadn't considered was possible). The question is then if a system such as Norton's Dome can be regarded as example of a classical system exhibiting true random behavior?

PS: @sophiecentaur your analogy with virginity is a bit amusing considering what your "tagline" says

 

[Baluncore]

The cross correlation of many maths functions can be zero. That doesn't mean they are random.

Obviously it does not work backwards.
If the two signals do correlate, then product detection will synchronously raise the signal in the noise, which will certainly not be random.

Your example of a lava lamp being "way more" deterministic is a bit like virginity.

Not my example; but the loss of virginity, by the light of a lava lamp, could not be random.

 

[andrewkirk]

Randomness cannot be a property of phenomena. It can only be a property of models, which we use to describe and understand phenomena.

To see this, consider a model of our spacetime that consists of a list of everything that ever happens in it. Nobody in our spacetime could compile such a list but, subject to certain not too onerous restrictions, a higher-dimensional organism that observed our spacetime from outside could. Such a model contains no randomness, because for every potential phenomenon, the model tells us whether it happens or not, with absolute certainty.

An interpretation of quantum mechanics is a model that contains QM as a proper submodel. The interpretation is not falsifiable (testable), at least with our current experimental capability. That's why we only call it an interpretation rather than a theory. In Karl Popper's terms it is not science but philosophy - metaphysics to be precise.

Some (probably most) interpretations of quantum mechanics involve randomness. Some do not.

 

[Giulio Prisco]

I tried to think of a truly random phenomena thatis not related to quantum physics, and i can't. Let's take heads or tails as an example, if you had all of the data about the throwing of the coin you could tell on which side it will land.

So does anyone know a random phenomena?

Or could you? It can be argued that "having all the data" doesn't make physical sense.

See:
Time is real, real numbers are not: Nicolas Gisin
and links therein

 

[sophiecentaur]

An interpretation of quantum mechanics is a model that contains QM as a proper submodel. The interpretation is not falsifiable (testable), at least with our current experimental capability.

Fair enough. Until we can find some 'pattern' in observed QM results we can't know they are not random. Until then (could be a cosmological timescale involved) the belief in Quantum randomness is just a belief. But, just as with Infinity, we have to go along with the Mathematicians and accept their axioms. Thankfully, they haven't really let us down yet - but that's for another thread.

Or could you? It can be argued that "having all the data" doesn't make physical sense.

This has been my main point, all along. Any classical model (theoretical) needs initial conditions to be input. However you dress up such a model, there will be that unknown (aka Random) factor which will affect the outcome.
Mostly, we design our systems to suppress the random effect and we try to reduce noise to a level where, for example, an amplifier's output can be relied on as a true version of the input.

Even a Pseudo Random Noise Generator uses circuits that suppress the Q random element.

But, however much we try to cover up the presence of Q randomness, any machine we make and claim to be random, can only get its randomness from Q processes.

 

[tinfoilunderwear]

I tried to think of a truly random phenomena thatis not related to quantum physics, and i can't. Let's take heads or tails as an example, if you had all of the data about the throwing of the coin you could tell on which side it will land.

So does anyone know a random phenomena?

No but watch this. Nothing up my sleeve, watch me pull a universe out of my hat.

 

[tinfoilunderwear]

Fair enough. Until we can find some 'pattern' in observed QM results we can't know they are not random. Until then (could be a cosmological timescale involved) the belief in Quantum randomness is just a belief. But, just as with Infinity, we have to go along with the Mathematicians and accept their axioms. Thankfully, they haven't really let us down yet - but that's for another thread.

This has been my main point, all along. Any classical model (theoretical) needs initial conditions to be input. However you dress up such a model, there will be that unknown (aka Random) factor which will affect the outcome.
Mostly, we design our systems to suppress the random effect and we try to reduce noise to a level where, for example, an amplifier's output can be relied on as a true version of the input.

Even a Pseudo Random Noise Generator uses circuits that suppress the Q random element.

But, however much we try to cover up the presence of Q randomness, any machine we make and claim to be random, can only get its randomness from Q processes.

You mean like the truth ?

[Mentor Note -- fixed quoted text]

 

[MysticWizard]

I recommend you read this wiki page: https://en.wikipedia.org/wiki/Superdeterminism

I think the definition of a truly random process is hard to prove because even observing certain events changes the outcome: https://en.wikipedia.org/wiki/Observer_effect_(physics)

If you are looking for the best random phenomenon known to man my bet would be on this: https://www.nature.com/articles/s41598-019-56706-2

If you just look for an easy way to get a random number generator, I think this should cover a lot of usecases: https://www.random.org/

 

[sophiecentaur]

If you just look for an easy way to get a random number generator, I think this should cover a lot of usecases: https://www.random.org/

I seem to remember a book in the library at work that was just a list of 'random numbers'. It was the only good source we had as the Eliott 803 computer was too busy doing hard sums at a clock rate of a few kHz.
I wonder if the authors ever challenged anyone under copyright laws?

 

[MysticWizard]

I seem to remember a book in the library at work that was just a list of 'random numbers'. It was the only good source we had as the Eliott 803 computer was too busy doing hard sums at a clock rate of a few kHz.
I wonder if the authors ever challenged anyone under copyright laws?

That makes me wonder if you ask 100 people to name a number between 0 and 100, how random would that be :P

 

[green slime]

Points are fictions, because it would take infinite information to identify any point.
Same with every irrational etc etc

Just for discussion: Origo?

Further the infinite information is impractical; just as the infinite length of every coastline relies on ever closer measurement. Sooner or later, a good approximation is good enough. :)

 

[sysprog]

The random numbers available from random.org are based on atmospheric noise.

 

[gentzen]

I think the definition of a truly random process is hard to prove because even observing ...

Indeed, the definition of a truly random process is hard. However, I don't get the "because even observing ..."

I tried my luck at a definition previously in this thread. I later realized one of its flaws (after reading reactions and other thoughts in this thread), but I didn't try to fix it and elaborate further, since the OP had left already:

The theories of probability and randomness had their origin in gambling and games more general. A "truly random phenomena" in that context would be one producing outcomes that are completely unpredictable. And not just unpredictable for you and me, but for anybody, including the most omniscient opponent. But we need more, we actually need to "know" that our opponent cannot predict it, and if he could predict it nevertheless, then he has somehow cheated.

But the most omniscient opponent is a red herring. What is important are our actual opponents.

The unpredictable for anybody is a mistake. It must be unpredictable for both my opponents and proponents, but if some entity like nature is neither my proponent nor my opponent (or at least does not act in such a way), then it is unproblematic if it is predictable for her. An interesting question arises whether I myself am necessary my proponent, or whether I can act sufficiently neutral such that using a pseudorandom generator would not yet by itself violate the randomness of the process.

(Using a pseudorandom generator gives my a reasonably small ID for reproducing the specific experiment. Such an ID by itself would not violate classical statistics, but could be problematic for quantum randomness, which is fundamentally unclonable.)

 

[MysticWizard]

Indeed, the definition of a truly random process is hard. However, I don't get the "because even observing ..."

I guess that one was meant more as: Be aware that your measurement method can influence the outcome

As for the definition, Wikipedia says:

This means that the particular outcome sequence will contain some patterns, that are detectable in hindsight, however not predictable with foresight.

I would then state that it is impossible to prove something is truly random because you would need a dataset with infinite time to predict any pattern however infrequent it may be.

 

[sophiecentaur]

That makes me wonder if you ask 100 people to name a number between 0 and 100, how random would that be :P

They’d all be trying to second guess the exercise. No one would choose zero or a hundred and also they’d avoid all the round numbers and well known multiples like the five times table. I’d bet that there would be many more ‘known’ prime numbers like 19.
This experiment must have been done. Somebody ( some random person) find a link for me please.

 

[votingmachine]

They’d all be trying to second guess the exercise. No one would choose zero or a hundred and also they’d avoid all the round numbers and well known multiples like the five times table. I’d bet that there would be many more ‘known’ prime numbers like 19.
This experiment must have been done. Somebody ( some random person) find a link for me please.

I would say pi.

 

[BWV]

Or this

https://en.wikipedia.org/wiki/Guess_2/3_of_the_average

zero is pareto optimal, but empirically people will pick a value roughly 1/5 of the highest number

 

[Dale]

That makes me wonder if you ask 100 people to name a number between 0 and 100, how random would that be :P

I always answer $\pi$, which is not random at all.

 

[256bits]

Is information finite classically?

Since there is a past and future light cone, the information from the past increase as -t; and we cannot predict the future . It would seem to be finite at the present.

 

[Dale]

Since there is a past and future light cone, the information from the past increase as -t; and we cannot predict the future . It would seem to be finite at the present.

Have you a reference that makes that argument?

 

[256bits]

Have you a reference that makes that argument?

I was rather wondering what you would reply to the fact that new information is entering a system as time progresses, and if it is a valid argument. Not sure what a reference to what a light cone is would accomplish.

 

[Dale]

I was rather wondering what you would reply to the fact that new information is entering a system as time progresses, and if it is a valid argument. Not sure what a reference to what a light cone is would accomplish.

Not a reference to a light cone. A reference to the argument that the fact that there are light cones implies that information is finite classically.

 

[256bits]

Not a reference to a light cone. A reference to the argument that the fact that there are light cones implies that information is finite classically.

sorry no reference.
i thought that it was self evident that the information that we can process is limited by our past light cone, with new information continuously arriving, information that we become aware of only as we move into the future.
Certainly we can predict from previous information gatherings, the mechanical workings of objects and state future sunrise, and say a solar eclipse, and verify the prediction when the event does occur. We had a limited set of knowledge about sunrise and now we have a bit more.

 

[Dale]

sorry no reference.
i thought that it was self evident …

No. It is not, and being a personal speculation it is not appropriate for PF.