Physics duo describe a way to guarantee true randomness

May 08, 2012 by Bob Yirka weblog
Physics duo describe a way to guarantee true randomness
Illustration of the bipartite set-up. Image (c) Nature Physics (2012) doi:10.1038/nphys2300

(Phys.org) -- In the natural world, it seems randomness is all around. Walk through a forest for example and it appears completely random, despite the fact that natural patterns emerge at almost every turn. In the human world, randomness is valued by all manner of people in a variety of circumstances, from testers of systems to ensure that weaknesses show up before products are sold to the public, to cryptologists, to those that run casinos where randomness ensures the house will win far more often than not. Unfortunately, guaranteeing true randomness is not something that comes easy. Take the lowly coin toss for example. A slight difference in weight on the “heads” side may cause the “tales” side to turn up a hundredth of a percentage point more often. Because of this, new work by a pair of physicists is catching the attention of people across a wide swath of interests.

Roger Colbeck and Renato Renner, as they describe in their paper published in Nature Physics, have figured out a way to virtually guarantee randomness in a constant stream of information. They say their technique can also transform a stream of not quite random data, to one that is truly random.

Their work is based on experiments done with quantum entanglement, whereby two particles appear to coexist in separate places. What happens to one, happens to the other at exactly the same time. Scientists don’t yet know how it happens, but they are now able to make it happen whenever they want. In looking at studies of quantum entanglement, Colbeck and Renner noted that physicists involved in the study tended to assume that the measurements used to study the phenomenon were originally random.

Because of this, the two calculated what would likely happen if a stream of data that was only partially random was correlated with other variables, thus ensuring that bits of information would not be random. If those bits of information were used to choose measurements on paired particles that were entangled that were caused to go down different paths the outcome would have to be independent of the other variables, which would mean true had been achieved.

The two say that this process could be applied to real world data to create true random data streams that could be used in virtually any application that requires the use of truly random numbers.

Explore further: Physicists design zero-friction quantum engine

More information: Free randomness can be amplified, Nature Physics (2012) doi:10.1038/nphys2300

Abstract
Are there fundamentally random processes in nature? Theoretical predictions, confirmed experimentally, such as the violation of Bell inequalities, point to an affirmative answer. However, these results are based on the assumption that measurement settings can be chosen freely at random, so assume the existence of perfectly free random processes from the outset. Here we consider a scenario in which this assumption is weakened and show that partially free random bits can be amplified to make arbitrarily free ones. More precisely, given a source of random bits whose correlation with other variables is below a certain threshold, we propose a procedure for generating fresh random bits that are virtually uncorrelated with all other variables. We also conjecture that such procedures exist for any non-trivial threshold. Our result is based solely on the no-signalling principle, which is necessary for the existence of free randomness.

via ScienceNews

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User comments : 38

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rrubin5
3.2 / 5 (5) May 08, 2012
The tititle uses the phrase " guarantee true randomness " while the abstract says " virtually uncorrelated". Is this just semantics or is it a headline writer being zealous?
antialias_physorg
3.8 / 5 (4) May 08, 2012
To qualify as a truly random sequence you need a sequence of inifinite length (because your fourier transfrom needs to be totally flat and that can only be the case for infinite length series).

The article describes how you can get randomness to any arbitrary degree. For a series of finite length this equates to true randomness (i.e. to a sequence that is as random as possible).
Lurker2358
3.4 / 5 (7) May 08, 2012
True randomness is non-falsifiable, because there could always be a pattern more complicated than what the observer considers.

There could even be a pattern beyond human or computerized comprehension, and it still would not be random.
Royale
5 / 5 (5) May 08, 2012
Can we at least agree that this could mean a much higher degree of randomness over a random number generator?
CHollman82
4.4 / 5 (7) May 08, 2012
If the "random" sequence is dependent on initial conditions (if it can be seeded) then it is not truly random.
antialias_physorg
2.3 / 5 (3) May 08, 2012
True randomness is non-falsifiable, because there could always be a pattern more complicated than what the observer considers.

However you can verify that the pattern that might be there needs more information to encode than the random noise you observe (in that case the pattern makes no sense for the using it)

Patterns are a means to represent an event (observation) with LESS information than required to store the even in its entirety.
Anything else is just fitting superfluous algorithms to a dataset.
El_Nose
1 / 5 (1) May 08, 2012

@chollman
-- i have am going to look into that statement - i don't know if that is perfectly true -- but my instincts tell me that is false ... my counter example is pi (which btw cannot be proved to NOT be random) and any trancendental number

remember that random does not mean it cannot be reproduced, just that the sequence is random. if you make a million copies of the same sequence is that sequence any less random??
CHollman82
4.2 / 5 (5) May 08, 2012
If the same initial conditions produce the same sequence every single time then it implies that EACH element of the sequence is either somehow tied to those initial conditions or to one or more of the elements that precede it, hence not random.

A truly random infinite sequence should be impossible to reproduce, otherwise it depends on SOMETHING... we may never figure out what though.

The decimal value of Pi may or may not be infinite, but it is not random.
CHollman82
4 / 5 (4) May 08, 2012
A better description of each successive digit of Pi is that it is unpredictable because we don't (yet) understand it's relationship to the previous digits. However, since the value is always the same given the same initial condition (that being that the value is the ratio of a circles circumference to it's diameter), then a relationship must exist.
kaasinees
1.4 / 5 (10) May 08, 2012
Randomness just means incalculable by a majority of people.
Randomness in the abstract sense does not exist, it only exists in a point of view where it cant be calculated.
Royale
1 / 5 (2) May 08, 2012
I'd say that's pretty accurate kaasinees.. at least in the way I picture its meaning..
I'm in the thought grouping that given enough information you could predict anything..
Perhaps even everything that happened after the big bang... I mean why not? If you've never read this Asimov short story: http://www.multiv...ion.html I think it sums up the idea pretty well...
CHollman82
3.7 / 5 (3) May 08, 2012
Royale, you realize that the modern understanding of quantum physics via Bell's inequality disagrees with your assertion of a deterministic basis for reality?

I am undecided on the issue. I understand the evidence favors a non-deterministic reality, but that's a damn hard pill to swallow.
Silverhill
5 / 5 (1) May 08, 2012
Such things as the Navier-Stokes equations, and the mathematics of complexity (a.k.a. chaos), seem to show that no finite amount of initial data can lead to an exact solution; so determinism appears to be impossible. (See also: Heisenberg uncertainty limit.)
antialias_physorg
3.7 / 5 (6) May 08, 2012
Double slit experiment. How can one argue for determinism if you can show that you cannot determine which slit photons or electrons travel through?
No amount of 'hidden variables' is going to make interference go away.
kaasinees
2.1 / 5 (11) May 08, 2012
Oh please we still hardly know what a photon exactly is, ofcourse we can hardly predict anything it does.

Sure we have a few models that fit for a photon but thats about it.
antialias_physorg
2.3 / 5 (6) May 08, 2012
We can see photons interfere. We can see ELECTRONS interfere in a double slit experiment. Not with each other but with THEMSELVES. They pass through both slits at the same time.

We have the tunnel effect where electrons pass through energy potentials for which they don't have enough energy. No amount of deterministic mumbo jumbo is going to explain that.

Quantum physics doesn't work at all if you go at it with determinism. But quantum physics works!

Observation trumps wishful thinking every time. And if observation says (as it does): "determinism is wishful thinking" then out the window it goes.
kaasinees
2.2 / 5 (10) May 08, 2012
We can see photons interfere.

Can you give me an article? Cause it sounds interesting.

We can see ELECTRONS interfere in a double slit experiment. Not with each other but with THEMSELVES. They pass through both slits at the same time.

I know about the double slit experiment but i didnt know we can see electrons interfere with themselves, article please?

We have the tunnel effect where electrons pass through energy potentials for which they don't have enough energy. No amount of deterministic mumbo jumbo is going to explain that.

That is purely assumptious..

Quantum physics doesn't work at all if you go at it with determinism. But quantum physics works!

Alchemists probably said the same thing...

Observation trumps wishful thinking every time. And if observation says (as it does): "determinism is wishful thinking" then out the window it goes.

That is where the problem is, in our POV we simply dont have the tools to observe at that level.
MrVibrating
1 / 5 (1) May 08, 2012
I envision true randomness as unpredictability due to acausality - rather than, say, mere complexity. So yep, as a devout determinist i consider that objectively impossible. From what i can understand of this article though (and the gramar ain't great) the proposed form of randomness is fully dependent on causality, plus of course a colleague to perform the entanglement - it's subjective randomness for Alice, but not Bob...
simplicio
3.7 / 5 (7) May 08, 2012
We have the tunnel effect where electrons pass through energy potentials for which they don't have enough energy. No amount of deterministic mumbo jumbo is going to explain that.

That is purely assumptious..

No it is not. Quantum tunneling is well known QM property. Look it up.

Quantum physics doesn't work at all if you go at it with determinism. But quantum physics works!

Alchemists probably said the same thing...

You are wrong - see Bell's theorem.
From wiki: "No combination of local deterministic and local random variables can reproduce the phenomena predicted by quantum mechanics and repeatedly observed in experiments".

Also what has ancient Alchemists to do with modern reality understanding?

That is where the problem is, in our POV we simply dont have the tools to observe at that level.

We have very good tools and most successful theory informing us. You need more research.
kaasinees
2.5 / 5 (8) May 09, 2012
We have very good tools and most successful theory informing us. You need more research.

You didnt understand my point i was trying to make.

I am not saying the observations are assumptious i am saying the mechanism behind it proposed is highly assumptious.
Just as gravity is a well observed phenomena, but the proposed mechanisms behind it is still highly speculative since we have no tools to research it or very "primitive" tools that might come close to a slightly better understanding.

That is just how the evolution of technology goes. Everything seems random until you grow a better understanding mostly because of knowledge on a lower scope of things.

Poeple behind "QM" can claim all they want, it doesnt make it true.
We simply dont understand anything at all on lower scopes, in that way in our POV yes thinks seem random, but they arent. Its an oxymoron in an absolute POV things simply CANT be random.

Why is science becoming so religious?
antialias_physorg
1 / 5 (2) May 09, 2012
Can you give me an article? Cause it sounds interesting.


http://en.wikiped...periment

They have done the experiment with single emission of photons, electrons (and even entire buckyballs!) which interfered with themselves
Single emission means: The intensity of the source is so low that on average less than one patricle is in the apparatus at any one time so as to exclude multiple entities interfering with each other.

Alchemists probably said the same thing...

but lechemists couldn't sho that it worked. they couldn't turn lead nito gold. Quantum physics CAN show that it works (see above).

To quote from the site linked above:
Richard Feynman called it "a phenomenon which is impossible ... to explain in any classical way, and which has in it the heart of quantum mechanics.
antialias_physorg
2.3 / 5 (3) May 09, 2012
i am saying the mechanism behind it proposed is highly assumptious.

I think you have a very basic flaw in your understanding of what science can and cannot do.

While science can never say "this is the definite rule and we will never find anything deeper" science is very well able to say "this is definitely NOT the rule - no matter how deep we go".

E.g. once we found Relativity we can - with definite authority - state that Newtonian gravity isn't correct. Irrespective of what we discover in the future it Newtonian gravity will never be correct.
No matter whether we find anything that describes gravity in a more fundamental way than Relativity or not.

And determinism is one of these rules of which we can definitely state: "that's not it".
CHollman82
3 / 5 (2) May 09, 2012
By definition, there is no explanation for true randomness, it is the end of scientific inquiry.
Royale
3 / 5 (2) May 09, 2012
Double slit experiment. How can one argue for determinism if you can show that you cannot determine which slit photons or electrons travel through?
No amount of 'hidden variables' is going to make interference go away.

Wait antialias, why?
You say no amount of 'hidden variables'. If by hidden you mean yet unknown I'd have to disagree. Wave particle duality is nutty I agree, but so is determining what gives mass to everything.. perhaps muti-dimensional theory could lead some strives in this area in the future.
Picture (as best a human can) a fourth spacial dimension Where there a mini blobs of mirrors or any photon shifting medium/particles/etc. Then we could explain the mechanism of action of said photons. Right? Or is this thought somehow flawed?
Royale
1 / 5 (1) May 09, 2012
I kind of have the idea that dark energy could be energy sucked in and out of a forth spacial dimension.. probably because I like the idea of it. Course that would throw energy creation/destruction in our 'three dimensions' out the window and piss a lot a of people off...
antialias_physorg
3 / 5 (2) May 09, 2012
I kind of have the idea that dark energy could be energy sucked in and out of a forth spacial dimension.

Why do you 'like the idea'? Just because the sentence contains a few buzzwords?

perhaps muti-dimensional theory could lead some strives in this area in the future.

Even multidimensionality will not make one path out of two in a lower dimension. You cannot project a higher dimensional singular path onto a lower dimensional multiple path (only the other way around: a higher dimensional multiple path MAY - but of course need not - appear in a lower dimension as a singular path).

You can figure this out yourself: Try to come up with a single, continuous path in 3D space that, when projected onto 2D (or 1D) planes (lines), will separate into two disjoint paths. No go.
But you can find two lines in 3D that when projected on a 2D plane will appear as being joined.
Tausch
1 / 5 (3) May 09, 2012
Wonderful comments/thread.
The "no-signaling principle" is a synonym for no FTL 'events'.
As far as information is concerned.
Feel free to correct this - if this is a flawed view.
Royale
not rated yet May 09, 2012

Why do you 'like the idea'? Just because the sentence contains a few buzzwords?

lol. I'm not shallow. You agree that if you have a fourth spacial dimension, there are things that we cannot measure, right? That would mean energy could be 'lost' from the 3D world we see. Right? That's all I was saying there. Energy wouldn't actually be lost; as a bird flying above 'flatland' could never be seen by 'flatlanders', we wouldn't be able to see energy flipping in and out, and affecting things in our realm.. like gravity, for instance..
Sure this is all conjecture, but so is this whole conversation about determinism.
antialias_physorg
1 / 5 (1) May 09, 2012
That would mean energy could be 'lost' from the 3D world we see.

However, we do not observe that. We would either see a breakdown in conservation of energy - or at the very least a problem with conservation of information. None has ever been observed.

Saying what 'could' occur with extra dimensions when it doesn't is the same as saying "and unicorns could be poking me in the back all day" when they aren't.
Such buzzword statetments are completely useless unless:
a) you observe something that merits a new theory
AND
b) you have a way to test it.

Anything else is just "wanking off at the mouth".

if you have a fourth spacial dimension, there are things that we cannot measure, right?

Flatlander are able to measure the curvature of their space without going outside (by simply laying down triangles and measuring the angles).

Anything that is 'above' us (i.e. which does not interact) is irrelevant to this universe. Anything that interacts can be measured.
Royale
1 / 5 (1) May 09, 2012
haha. Well played. Fair points. (I especially loved the unicorns line).
You're right in that those things haven't been measured or observed that I'm aware of. As for the dark energy/matter things I guess they really can't try to measure them yet.. perhaps if/when we find the Higgs Boson it will help explain these things too.
Terriva
1 / 5 (4) May 09, 2012
I kind of have the idea that dark energy could be energy sucked in and out of a forth spacial dimension.. probably because I like the idea of it. Course that would throw energy creation/destruction in our 'three dimensions' out the window and piss a lot a of people off...
Actually, you can be even right with it at conceptual level. In AWT the substantial portion of dark matter is formed with neutrinos, i.e. the solitons of gravitational waves, the energy of which is residing in additional dimension space-time in similar way, like the energy of (Falaco solitons) floating on the water surface. The energy of these vortices is concentrated at the third dimension, which is directly unaccessible from 2D water surface.
Cynical1
1 / 5 (1) May 12, 2012
By definition, there is no explanation for true randomness, it is the end of scientific inquiry.

Well said.
However, the character of scientific inquiry will not accept that there IS an "end". To accept it belies the very nature of "scientific inquiry".
The next question would be -
WHY (a variable generator word) is there an end?
Followed by -
Since there appears to be an end - what came before?
Or what lies beyond the "end"?
IMHO the universal rule is to add a variable or 2 to each successive action - which becomes 2(number chosen randomly) variables in the next iteration, then(again, number chosen randomly - sort of) 4 in the next - and so on... Kinda like what it APPEARS these guys are doing. That just means our observation of it just lags behind the understanding of it.
Observation is thusly indicated as scalar determinate, depending on the POV of the observer.
So, I guess I am in the determinist camp...
antialias_physorg
not rated yet May 12, 2012
However, the character of scientific inquiry will not accept that there IS an "end". To accept it belies the very nature of "scientific inquiry".

Why not? Science gathers information. If there is no information to be gathered (as in the case of true randomness) then no science can be done. However, as noted before, to establish true randomness requires an infintely long series of data points. And that's not in the cards (at least not in this universe)
WHY (a variable generator word) is there an end?

See above.
Since there appears to be an end - what came before?

Ah. the old: "what do tuesdays smell like?" question.

...Ask a nonsensical question, don't expect to find a sensible answer. (In computer science we call this approach "GIGO". Garbage In - Garbage Out)
Cynical1
1 / 5 (1) May 12, 2012
Since there appears to be an end - what came before?

Ah. the old: "what do tuesdays smell like?" question.


Bacon usually. And I should have learned to not to mess with a ninja semantics master by now...
That said, however - Science, being a concept and practice of humans (ever the busy minds), has ALWAYS asked new questions of answers that were considered at end (by other humans, coincidentally). If it didn't, we wouldn't be here (on this comment thread) to even speculate on these inanities.
We can never know a true nature of a "nothing" because a POV - an observation point - can't exist there (by current definition).
When and if we can establish one (And they're probably trying) - then it is not nothing - again.
An abstract construct (usually best viewed with beer lenses) is all we can hope to know...
The REAL question is - why didn't I just take the blue pill?
antialias_physorg
not rated yet May 12, 2012
If it didn't, we wouldn't be here (on this comment thread) to even speculate on these inanities.

We have to distinguish inanity from insanity, here. (insanity in its literal sense: not sane, not logically consistent)

The reason why many of the 'big' questions haven't been answered is because they are self-defeating (oxymoronic). In some cases it's subtle (why is there something rather than nothing; what is the meaning of...anything; etc.) in other cases it's not so subtle (what is outside the universe; what was before the universe; ...). But in all cases the unspoken premise in the question already precludes an answer.

The REAL question is - why didn't I just take the blue pill?

Just take all pills and things might start to make sense.
Dark_Squirrel
1 / 5 (1) May 13, 2012
Implement this "True Randomness" in some form of encryption, put it in use on the internet. Then I give it 3 years before some random kid from Korea finds a way to break it. That is how we find if this is truly random.
Tausch
1 / 5 (2) May 14, 2012
I truly miss Cantor.
CHollman82
1 / 5 (1) May 14, 2012
Implement this "True Randomness" in some form of encryption, put it in use on the internet. Then I give it 3 years before some random kid from Korea finds a way to break it. That is how we find if this is truly random.


If the Korean kid who breaks it is truly random then this method will be vindicated!