Top Diaries

Any experimental verification of superluminal communication?

Kind of.

And also here.

I can understand the group velocity argument, but what bothers me is that the rationale for 'proving' that superluminal communication can't happen seems very similar to the one that was being used to 'prove' with absolute relativistic certainty that the group velocity has to be less than c.

This doesn't 'prove' anything about what's possible, but it does make me suspicious of the rigour of the arguments that are being used.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Wed Jan 2nd, 2008 at 04:59:35 PM EST
[ Parent ]

Re: Now Way Past Entanglement (none / 0)

Oh, that!Faster than a Speeding Light Wave - UFO Evidence

Researchers have now measured many group velocities higher than c. "It's just not true what they say in the textbooks," says Raymond Chiao of the University of California at Berkeley. For example, a Gaussian shaped light pulse can travel faster than c through some highly absorbing materials. The explanation is that the central piece of the pulse is attenuated more than the earliest piece. Although the pulse shape is unchanged, it comes out smaller, and the "leading edge" of the input pulse is transformed to become the peak of the emerging pulse, a process called "reshaping." So no part of the pulse is actually transmitted faster than c, says Chiao.

That doesn't constitute a test of superluminal transmission of information, though I can imagine an experiment being designed on the basis of this phenomenon.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 05:24:41 PM EST
[ Parent ]

Decoherence (4.00 / 3)

I understand that the unmitigated connections are at the quantum level, so when you say they don't rise above the mesoscopic, that does not come as any particular shock.

You are asking me to explain how a new theory of Quantum Mechanics would allow Quantum Mechanics to solve our problems. But there is no way I would expect that.

And not only because our problems are not going to get solved.

Rather, my guess is that a correct understanding of Quantum Mechanics would be a new model of the world, and that model would suggest many things, not only about Quantum Mechanics. It would suggest things that would compel us to CORRECT OUR BEHAVIOR.

What might those things be? We'll know if it happens.

The Fates are kind.

by Gaianne on Wed Jan 2nd, 2008 at 12:57:51 PM EST
[ Parent ]

I feel compelled to take a stab at a diary on quantum mechanics and ontology.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 01:01:01 PM EST
[ Parent ]

Hooray!

Any idiot can face a crisis - it's day to day living that wears you out.

by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 01:17:01 PM EST
[ Parent ]

You do have a degree in philosophy, right? I'll need backup.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 01:26:15 PM EST
[ Parent ]

okay, I'll move to the office and get all the big books out.

Any idiot can face a crisis - it's day to day living that wears you out.

by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 01:29:36 PM EST
[ Parent ]

Only after I've posted the diary, though :-)

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 01:41:55 PM EST
[ Parent ]

Well it is only upstairs, if I can get the pile of cats off me.

Any idiot can face a crisis - it's day to day living that wears you out.

by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 01:43:38 PM EST
[ Parent ]

Are you Dr. Strangelove in disguise?

Index of Frank's Diaries

by Frank Schnittger (mail Frankschnittger at hot male dotty communists) on Wed Jan 2nd, 2008 at 03:45:14 PM EST
[ Parent ]

Football chant?

Any idiot can face a crisis - it's day to day living that wears you out.

by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 08:15:34 PM EST
[ Parent ]

Re: Decoherence (4.00 / 2)

By the way, the problem that decoherence attempts to solve is how it is possible that out of quantum mechanics arises a macroscopic world that is more or less consistent with the Western metaphysics you lambast.

That is the real problem. How do you construct a metaphysics that at the same time contains heuristics for the microscopic and for the macroscopic.

I agree with a lot of people that quantum gravity is likely to result in this new heuristics, but I honestly fail to see how 1) any quantum gravity is going to be testable other than by internal consistency (which you lambast), that is, how experiments are going to be accessible; 2) how knowledge of quantum gravity could affect (or would have affected) political economy.

Feynman once said that the problem with hard-nosed scientists is not that they lack imagination but that what they imagine is constrained by everything they know to be approximately true.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 01:06:03 PM EST
[ Parent ]

"other than by internal consistency (which you lambast)"

???

The Fates are kind.

by Gaianne on Wed Jan 2nd, 2008 at 02:11:29 PM EST
[ Parent ]

http://www.watchingyou.com/woowoo.html

Maybe I misread you as to at what point Mathematics went wrong.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 02:15:35 PM EST
[ Parent ]

Mathematics went wrong (4.00 / 2)

Well, my complaint was, that 30 years after Goedel showed mathematics was not exactly planted on solid bedrock, mathematicians were still pretending that it was.

I had no complaint about internal consistency--but what we were getting was faith. In a sense there was no choice about that, but I thought that in that case we should own up to it.

Then again, a non-formal proof of consistency, might serve, but--and now I am wandering off-topic, perhaps those funny little symbols were not as important as everybody thought? I was slowly coming around to the intuitionist view that mathematics should be comprehensible. Even if the intuitionists treated Cantor very badly--which they did--they weren't wrong about everything. Hilbert's project had its uses, but the core of it had failed. It was time to let mathematics be done in a style appropriate to its content.

So during this period, it was the logicians, not the mathematicians, who were my guides. They wanted proof of consistency but knew they had not gotten it, and owned up. They knew they needed to do something about it, too, even if what they did lay outside of logic.

The Fates are kind.

by Gaianne on Wed Jan 2nd, 2008 at 02:51:24 PM EST
[ Parent ]

Re: Mathematics went wrong (4.00 / 2)

Personally I think we'd be well served by taking a constructivist approach to mathematics. A lot of the apparent paradoxes and monsters of functional analysis go away if you take a constructivist approach. Which, in fact, is good for applied mathematics such as physics because a lot of conundrums just melt away.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 03:10:32 PM EST
[ Parent ]

Re: Decoherence (4.00 / 11)

Gaianne:

It would suggest things that would compel us to CORRECT OUR BEHAVIOR.

It's actually not hard to understand what the problem is. Although the Western Mind (including Colman's, at a guess) shrinks back in horror from mysticism and explicit dualism, it still works on the assumption that Mind is separate from Reality, and that the only way to understand Reality is by making Mind (i.e. abstracted pattern recognition) and Reality as separate as possible.

You can experiment on Reality, but you're not allowed to admit that you take part in the experimental experience directly. That's called being subjective, and it's a terrible sin.

Put simply, we don't see ourselves as an organic part of the physical world. We see ourselves as separate and detached from it. It happens to us and around us, but it's not a deeply felt or experienced part of us.

So physics is still a theory of distant-mindedness rather than a theory of participation, and Goedel is the inevitable result of trying to find a theory of mind which isn't grounded in experience - a castle in the air with no foundation, because foundational axioms are based in participation and experience and can't be derived from pure pattern matching.

Relativity and QM have been suggesting - inconclusively, so far - that participation is a pre-requisite for deep understanding.

This is very uncomfortable for rational dualists, and they're still not sure what to make of it.

Inevitably the disconnection leads to ravings and mania like the international economic system, where pure algorithms of value disconnect from reality so completely that they're in serious danger of destroying themselves.

This won't change until the detachment ends. It doesn't have to end in a naive participation mystique, because that's often every bit as superficial as it seems to be. Doing lots of drugs and saying 'Hey, wow, that's like, really cool' isn't any more insightful and useful than it seems to be.

But the common factor among mystics is that they don't feel the separation, either between themselves and physical reality, or between themselves and others. And that makes them consicous participants with a personal relationship to their surroundings, rather than slightly confused and anxious passengers who feel embattled and detached from them.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Wed Jan 2nd, 2008 at 05:23:42 PM EST
[ Parent ]

Re: Decoherence (4.00 / 3)

Excellent, tbg, the future is participative, or there is no future...

"The future is already here -- it's just not very evenly distributed" William Gibson

by ChrisCook (cojockathotmaildotcom) on Wed Jan 2nd, 2008 at 05:34:10 PM EST
[ Parent ]

I try for concision (none / 1)

but you achieve it.

Very neat and clean. :)

The Fates are kind.

by Gaianne on Wed Jan 2nd, 2008 at 06:32:39 PM EST
[ Parent ]

Re: Decoherence (4.00 / 2)

Although the Western Mind (including Colman's, at a guess) shrinks back in horror from mysticism and explicit dualism, it still works on the assumption that Mind is separate from Reality, and that the only way to understand Reality is by making Mind (i.e. abstracted pattern recognition) and Reality as separate as possible.

Thank you for attributing idiotic views to me. I always appreciate that, especially when they're diametrically opposed to my actual views. I guess I'll just have to become a mystic so I can truly understand things. <sigh>

Turns out that earlier I was discussing with Migeru in IM that the distinction between observer and the observed is entirely artificial. Mind you, mysticism doesn't help at all, because it moves the observer further from the observed, not closer - the observer is really outside reality, floating around in a higher state of consciousness with the other enlightened souls, man.

by Colman (colman at eurotrib.com) on Wed Jan 2nd, 2008 at 07:38:21 PM EST
[ Parent ]

distinction between observer and observed (none / 0)

the distinction between observer and the observed is entirely artificial.

Could you develop that point further, or any chance of posting that segment of your IM chat?

(Or maybe Migeru is already planning to include it in his diary on quantum mechanics and ontology?)

Truth unfolds in time through a communal process.

by marco on Wed Jan 2nd, 2008 at 08:10:30 PM EST
[ Parent ]

Re: distinction between observer and observed (4.00 / 3)

No, the diary on ontology is going to be on boring stuff such as

what is an object?
take the physics of quasiparticles and the whole idea of objects falls apart
what constitutes the identity of an object?
take the physics of fermion, boson, anyon statistics and compare with maxwell-boltzmann; take the Gibbs paradox
but if these topics are a prerequisite for discussing ontology, who can take part in the discussion?
it takes the fun out of philosophy
</lecture>

As for the requested discussion on the separation between subject and object:

Migeru: it's funny how QM philosophical problems always end up at the conscious observer
... but I think it's about philosophy, not about quantum consciousness
Colman: Yes.
Migeru: it's like the philosophhy of probability: it's also broken
Colman: It's an artificial split between system and observer. Or somethign along those lines.
Migeru: do you know about the holographic principle in quantum gravity?
Colman: I've heard of it. But I forget...
Migeru: it says roughly... you can put a boundary wherever you want
the area of the boundary is a bound on the information entropy of either half
it appears likely to be a key principle of the new theory
but quite what it has to do with consciousness...
though it does seem to have something to do with these boundaries between systems
Colman: Hm.
Migeru: subject and object, etc
Colman: Could do. The distincition is artifical.
Migeru: the problem is
since we don't understand consciousness
we can't do a toy model of a self-aware entity
Colman: No.
Migeru: so there's no way to put that in QM
and talking about QM as the basis of consciousness just confuses things even more!

Flame away!

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 08:21:53 PM EST
[ Parent ]

Re: distinction between observer and observed (none / 0)

How is the Philosophy of probability broken?

Any idiot can face a crisis - it's day to day living that wears you out.

by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 08:31:14 PM EST
[ Parent ]

Re: distinction between observer and observed (4.00 / 3)

One of the main ways IMHO is that the frequentist probability interpretation confuses the definition of probability with the operational way in which probabilities are measured. It takes the law of large numbers as the definition of probability, which makes the conceptual edifice dangerously close to circular.

A big problem with the interpretation of Quantum Mechanics is actually disentangling the philosophy of probability from specifically quantum mechanical conceptual problems.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 08:35:27 PM EST
[ Parent ]

Re: distinction between observer and observed (none / 0)

now that's going to take at least a pint, a bath, and an hour of thinking to come up with an answer to.

Any idiot can face a crisis - it's day to day living that wears you out.

by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 08:52:44 PM EST
[ Parent ]

Re: distinction between observer and observed (4.00 / 3)

You guys are in danger of disappearing up your own arses, so a bath would be good. I'm told that long threads are almost always the result of flame wars and there hasn't been a bit of excitement here all night! Can someone please light a fire under these guys so I can scramble some lieutenants?

Index of Frank's Diaries

by Frank Schnittger (mail Frankschnittger at hot male dotty communists) on Wed Jan 2nd, 2008 at 09:17:53 PM EST
[ Parent ]

Re: distinction between observer and observed (4.00 / 4)

But aren't there interpretations which don't assume consciousness is necessary?

This seems to be a good thing because otherwise you end up in a solipsistic universe, where you personally are a cause of the Big Bang and all 13 and a bit billion years of everything that happened afterwards. (For varying and approximate values of 'you', at least.)

Assuming consciousness is essential seems to be another spin around the implicit dualism of mind over matter. Although it looks as if it's saying that mind and matter are linked, the implication is really that matter only appears when mind decides it does - which could be a little bit suspect, I think.

How much of a mind do you need before it's conscious enough to start deciding observables?

by ThatBritGuy (thatbritguy (at) googlemail.com) on Wed Jan 2nd, 2008 at 08:53:28 PM EST
[ Parent ]

Re: distinction between observer and observed (none / 0)

Why would it have to be you? perhaps your existence is only guaranteed by the existence of another individual who is the actual observer. That would mean that the biblical "thou shalt not kill" might be to guarantee your own existence and that of the universe, by maintaining the life of the observer.

Any idiot can face a crisis - it's day to day living that wears you out.

by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 09:03:26 PM EST
[ Parent ]

Re: distinction between observer and observed (none / 1)

That's why I asked about how much consciousness you need.

There's a neat paradox which says that if you try to kill yourself in a quantum experiment, you can't do it. If you did you wouldn't be able to observe the result of the experiment. So it would never happen.

Your colleagues meanwhile can see a quantum suicide note, and possibly a dead body.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Wed Jan 2nd, 2008 at 09:21:13 PM EST
[ Parent ]

Re: distinction between observer and observed (4.00 / 2)

The flip side of that one is that we're all immortal, we only see other people die and there's at least one history of the universe in which the observer persists.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 09:22:33 PM EST
[ Parent ]

Re: distinction between observer and observed (none / 0)

So that makes the worlds militarists, those who are not taking Pascal's wager in that form.

Any idiot can face a crisis - it's day to day living that wears you out.

by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 10:42:47 PM EST
[ Parent ]

Re: distinction between observer and observed (4.00 / 4)

You're right, there are interpretations that do not require a conscious observer: "consistent histories" for instance. But here's the thing: most of these interpretations address primarily the problem of decoherence, that is, the passage from quantum-mechanical interference of complex amplitudes to classical addition of real (and positive) probabilities. What none of them address is the (not quantum-mechanical but probabilistic) problem of actuality (which of the actual histories is realised), which is basically the (probabilistic, not quantum mechanical) problem of assigning a probability to a single event.

Finally, there's an additional twist to this whole discussion which is that decoherence is supposed to be about breaking entanglement, a concept which figures prominently in gaianne's writeup and seems central to the "everything is connected" woo-woo (excuse me) narratives. Now the twist is that entanglement itself is not well defined. It is possible to write down a state of three particles such that depending on the result of a measurement made on A, B and C may or may not be entangled (and cyclic permutations of A, B and C). So, "connectedness" of A, B and C means that "connectedness" of B and C depends on what happens to A far away. This state is called sometimes a Borromean state, by analogy with the borromean rings which are not linked pairwise, but are linked as a set of three.

Back to the beginning, consciousness is not essential but unless a conscious observer is involved, philosophical problems with quantum mechanics seem rather mild to nonexistent, which again suggest a philosophical problem, not a problem with quantum mechanics. The central question is: how are entanglement or interference perceived? Remember Bohr's "no phenomenon is a phenomenon unless it is an observed phenomenon".

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 09:20:25 PM EST
[ Parent ]

Re: distinction between observer and observed (none / 1)

"'woo woo' is not shorthand, it's rudeness."--Bertrand Russell

There are 41 statements to the Woo Woo credo, many of which demonstrate that it is a term coming out of Usenet flamewars--or somesuch. To understand if a person is a woo woo, one would have to run their comments via the list--and if they matched up, you can then call them "woo woos" and start an argument--it's an argumentative term, with some humour but clearly aimed at a certain Usenet type of character (the kind who reports you to the sys admin etc.) The list does have some enjoyable moments. I recommend numbers 4, 8, 9, 12, 22...wow, 22! But I don't recommend using it as shorthand because it is clearly meant to be derogatory.

Don't fight forces, use them R. Buckminster Fuller.

by rg (leopold dot lepster at google mail dot com) on Thu Jan 3rd, 2008 at 04:55:21 AM EST
[ Parent ]

Re: distinction between observer and observed (none / 1)

But there's another interpretation which is a kind of extremist Copenhagen view. It says that QM is a tool which calculates probabilities. And that's all it is.

It doesn't try to define what really happens, it doesn't assume that wave functions are 'real' or even that they evolve. All it says is that if you measure a system at time t, the probabilities of the different outcomes are the real part of etc.

The fact that states can be in various baroque non-local superpositions before the interaction doesn't change this. The probabilities will still be consistent and computable.

What none of them address is the (not quantum-mechanical but probabilistic) problem of actuality (which of the actual histories is realised), which is basically the (probabilistic, not quantum mechanical) problem of assigning a probability to a single event.

"It's random within probabilistic constraints" seems to be all that QM can tell you.

There may be a theory which defines the ontology in more detail. But QM doesn't seem to be it.

The only difference between an observer and a non-observer is that the observer is consciously aware of a measured value. But that doesn't define the value.

What's annoying about QM is that it tries to conflate different issues. There's a difference between the physical interaction needed to make a measurement and the mental process of experiencing the measurement. There's also non-locality, which supposedly makes everything very spooky and has somehow - for some reason which has never been properly explained, because it's not really needed - been linked to mental experience, even though it's completely distinct.

Consciousness
Micro to macro amplification ('measurement')
Non-locality etc
'It's all one' woo woo

are all different. I'll take the middle two. I won't accept the other two until someone does an experiment in which two observers measure two contradictory observables from the same quantum system at the same time.

Remember Bohr's "no phenomenon is a phenomenon unless it is an observed phenomenon".

That's almost makes sense, but doesn't, because in the limit it says that nothing in the universe exists unless it's observed. Which seems unlikely - otherwise you're back to solipsism again, with every possible wave function in the entire history of the universe converging on your viewpoint.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Thu Jan 3rd, 2008 at 06:13:12 AM EST
[ Parent ]

Re: distinction between observer and observed (none / 0)

Great comment.

Regarding Bohr, isn't that very similar to what Kand said about noumenon and phenomenon? Aren't there serious epistemological issues at the core of all this?

ThatBritGuy:

"It's random within probabilistic constraints" seems to be all that QM can tell you.
There may be a theory which defines the ontology in more detail. But QM doesn't seem to be it.
The only difference between an observer and a non-observer is that the observer is consciously aware of a measured value. But that doesn't define the value.

Which is why I want to make a diary referring to a number of out-there models and experiments from Quantum Mechanics and ask people to hash out the ontology. Because things like "what is an object" are not quite clear. And it is a lot easier to say "the universe is purely relational" than to build any useful model out of that insight, which is why a lot of physicist will talk in those terms around a pool table, but few papers get written.

We have met the enemy, and he is us — Pogo

by Carrie (migeru at eurotrib dot com) on Thu Jan 3rd, 2008 at 06:21:27 AM EST
[ Parent ]

Re: distinction between observer and observed (none / 0)

And it is a lot easier to say "the universe is purely relational" than to build any useful model out of that insight, which is why a lot of physicist will talk in those terms around a pool table, but few papers get written.

sniff, sniff Chris, is that you cooking up another batch of your pudding somewhere?

Truth unfolds in time through a communal process.

by marco on Thu Jan 3rd, 2008 at 06:48:39 AM EST
[ Parent ]

Re: distinction between observer and observed (none / 1)

Regarding Bohr, isn't that very similar to what Kand said about noumenon and phenomenon? Aren't there serious epistemological issues at the core of all this?

That depends what you expect physics to do. There's a difference between explaining reality, modelling reality, and defining reality.

I think realistically (sic) the best you can hope for is models of increasing sophistication and usefulness. Explaining reality is best left to theologians. (Not that they have a clue either, but it keeps them busy.)

No one should be trying to define reality, ever, but it's easy to fall into the trap of believing that a theory with predictive power is what's going on ontologically.

Too much physics is still cursed by Platonism. According to Penrose et el., models supposedly float around outside reality telling it what to do.

But there's a huge gap between using experimental recipes to predict what's going to happen next, and assuming there's a Central Recipe Database running things behind the scenes.

One is pattern recognition, the other is metaphysics. One assumes that reality works consistently and the consistency can be enumerated. The other makes unwarranted assumptions about the mechanisms which create that consistency.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Thu Jan 3rd, 2008 at 10:19:21 AM EST
[ Parent ]

Colman:

Turns out that earlier I was discussing with Migeru in IM that the distinction between observer and the observed is entirely artificial.

It's not artificial, it's a useful way of relating to the world.

What it isn't is the only useful way of relating to the world.

And there's a bit of a gap between thinking it as an interesting concept and living it, even a little.

Colman:

Mind you, mysticism doesn't help at all,

If you know it's all lazy woo woo by definition, it wouldn't.

Colman:

the observer is really outside reality, floating around in a higher state of consciousness with the other enlightened souls, man.

It's lucky you never find any of that in science, isn't it?

by ThatBritGuy (thatbritguy (at) googlemail.com) on Wed Jan 2nd, 2008 at 08:34:39 PM EST
[ Parent ]