MIT wants quasars to help put free will to rest

The last of three loopholes held to remain in Bell's Theorem, “setting independence”, is under the spotlight with an MIT research group saying that quasars could be used as random number generators and help prove* the validity of quantum mechanics. (*The Register is well aware that quantum mechanics has withstood the most …

[ecofeco]

Does this mean...

... the cat will no longer even be in the box?

Wait, who took my coat?!

[tony2heads]

Re: Does this mean...

That was a cat walking off with it

http://www.youtube.com/watch?v=mdFeYZVQKmY

[Paul J Turner]

...cannot possibly have any “causal contact” in the last 14 billion years.

Unless all very old matter in the universe is somehow entangled at birth since it was all a very small volume that went bang!

If so, they could still be 'in contact' because how can you assert that the distance between them is a sufficient safeguard if (as I think I heard here somewhere) entanglement effects are FTL?

[Richard 12]

Only if it's quantum

I think the idea here is to completely disprove classical mechanics, so if the only way it can work is because of quantum at either end, then it still works.

It's probably quantum.

[Ashton Black]

Re: ...cannot possibly have any “causal contact” in the last 14 billion years.

I think you've misunderstood. They're not suggesting an entanglement between two particles 14 billion light-years apart, but suggesting that any observer bias could be mitigated by using quasars as random switch controllers for the standard "Bell's Inequality" experiment which has been done many times, always finding in favour of the Quantum Mechanics theory, over a theory of locality.

You are right about the effects of entanglement, however, they do seem to be FTL, but since no usable information is passed, without a classical channel, it does not, the theory goes, breach the relativity barrier.

[Paul J Turner]

Re: ...cannot possibly have any “causal contact” in the last 14 billion years.

I understood, I was just wondering 'what if the two quasars aren't as mutually random as we suppose'. Then using an observation of some characteristics of them might result in not mutually random observations via the switch controllers.

[Ashton Black]

Re: ...cannot possibly have any “causal contact” in the last 14 billion years.

Ahh, I lounge corrected. That is a valid point. Whatever this characteristic, it would be another unknown. I know you could entangle a subatomic particle, but at the macro level of a quasar?

[dan1980]

Re: ...cannot possibly have any “causal contact” in the last 14 billion years.

Ashton & Paul

I think Richard's response seems sensible - if there is some kind of entanglement between the two quasars that biases the result then that entanglement itself is a quantum (and thus non-classical) effect and would therefore presumably count 1 for QM.

I'm no physicist (or really much of anything) but that does seem logical. That said, if a scientific proposition seems logical to me then that would suggest I probably have misunderstood it.

[Julian Bond]

There's a thing in here that always does my head in. "quasars that are so far apart, they cannot possibly have any “causal contact” in the last 14 billion years" So there can be a pair of quasars that are both in our light cone but are not in each other's light cone within the current life of the universe. Uh-huh?

[Destroy All Monsters]

Because inflation blasted things apart faster than "c" from each other, so currently every observer is getting more and more light from the universe that was thrown out beyond his "event horizon" way back when.

So we are in the middle and already see both ... but they don't see each other yet. Unless the universe is smaller than expected.

[Anonymous Coward]

So if this test succeeds, the correctness of quantum theory will then rest on the correctness of the inflation theory? I'm not sure that adds up to a great deal of advance given the relative amount (and precision) of testing each theory has received so far.

[Jonathan Richards 1]

It still all happens in a lab. right here

“In other words, the perception of quasar A determines the settings to detect particle A, and the perception of quasar B sets the detector for particle B,” MIT might have stated. “If, after multiple measurements with this experimental setup, scientists seem to have found that the measurements of the particles were correlated more than predicted by the laws of classical physics, Kaiser says, then, ummm, hold on...”

HTH :)

[John Smith 19]

Intriguing.

Now what if the level of correlation is only at the level of classical quantum physics?

BTW I think this is a very tricky experiment because you're not looking to null out an effect.

My instinct is it will take some very careful hardware design to ensure that no part of the signal received from Pulsar A seeps into the hardware chain of Pulsar B (and vice versa) causing their outputs to be more correlated than the classical result.

But that result is exactly what you expect to happen in this experiment.

[Destroy All Monsters]

Re: Intriguing.

Yeah it's easier to do the experiments based on what the government's left and right hand are doing.

Fully uncorrelated.

[Grikath]

Re: Intriguing. @ destroy all monsters

Wouldn't work, I'm afraid.

It's a well-known fact that direct observation of any part of government will make that part cease to function, thus defeating the purpose of getting any useful information out of it.

One could try indirect observation, by measuring the effect of government interference on normal processes, but a buttered-toast/carpet test to validate those results invariably indicates Malevolence. You'd first have to apply Deja-Fu to make those results useable.

Edit: Or leave it overnight to Soak.

(Had to squeeze that one in...)

[fLaMePrOoF]

Seems flawed to me as everything in existence had causal interactions at the big bang if space and time are not precedant to quantum interactions but rather are a product of them...

[Charles 9]

I think that's the intention. See if there is a correlation between two things 13 billion light years apart, then how would classical mechanics explain it (since under that, it would take that long for one to react to the other simply due to the limitations of the speed of light)? And I would assume the two quasars would be chosen such that we wouldn't be equidistant between them, removing that possible coincidence.

[Eguro]

“If, after multiple measurements with this experimental setup, scientists found that the measurements of the particles were correlated more than predicted by the laws of classical physics, Kaiser says, then the universe as we see it must be based instead on quantum mechanics.”

I feel as if that last part is quite absolute: "must be based" - perhaps "must be presumed to be based" - or "is very much more likely based" - or "is as far as we can tell based"

I know it probably relates to press releases and such things, but I never really like it when scientists speak with absolute certainty, especially about such cutting edge stuff.

[dan1980]

@Eguro

My correction would read:

“If, after multiple measurements with this experimental setup, scientists found that the measurements of the particles were correlated more than predicted by the laws of classical physics, Kaiser says, then the universe as we see it cannot be based on the laws of physics dictated by the classical model.”

The follow-up would be to say that such a result would be a strong indicator for the quantum mechanical model given that it is currently the best framework to explain the otherwise anomalous events.

[James Loughner]

Not real

Since from the point of view of a photon there is zero distance between objects and the universe has stopped. It shows that relativity like quantum mechanics just is a limit to what us electromagnetic beings can measure. Yes think about it everything we know is from electromagnetic fields. Bang you hand on a table that is the result of electrons repelling one another.

Relativity is based on the fact that we must use electromagnetic things to measure the universe and are thus restricted to the speed of light which cause distortions in our measurements. Like quantum mechanics is limited because we can not measure things exactly because we change what we measure by measuring it. So both are more a statement of our ability to measure the world then the true nature of the world.

[Michael Wojcik]

Re: Not real

So both are more a statement of our ability to measure the world then the true nature of the world.

The hypothesis that there is a "true nature" of the world which exceeds our ability to observe (directly or through any system of proxies) is a purely metaphysical one, since by definition no such "nature" can have any observable consequence for us. Where epistemology stops, there science stops too. You can say anything you like about this purported essence, and your audience may find your ideas more or less persuasive; but they will remain forever nothing more than matters of belief.