Quantum Weirdness

[Dancing David]

Ah, but if you understood the Multiverse Interpretation of QM then you would

ROTFLMAO!

That means somewhere people actualy laugh at my jokes!

 

[Dancing David]

Rolfe, I made it though part of that Milgron,

I skiped the interpretation of the history of quantum mechanics, it seemed to be reasonable. But suffering from the usual errors.

Number One error: the observer thingy, it is not the act of observation that makes for QM wierdness, it is the ineraction that leads to the observation!


Then they proceded to talk about quantum entangle ment and time travel.

They pepper heavily with phrases from QM, and even drags out Heisenberg and Schroedinger and maxwell. But it is all the asme as.

Placing a copy of a reasearch paper of a guns shot wound and saying that the magic of the reseach shall heal the wound.

The person is a quack, you can not apply the effects of micro scale to the macro scale, the wave forms cancel out the quantum wirdness.

I am very supised they did not invoke Bose-Einstiens Condensate somewhere and the left out the Cosmic Microwave radiation.

I think that it could be dome just as well with a computer proram insertin scientific phrases into a crack pot scheme.

 

[Humphreys]

Number One error: the observer thingy, it is not the act of observation that makes for QM wierdness, it is the ineraction that leads to the observation!

David, I always believed it was the interaction that caused the photon to be absorbed, and not observation or consciousness.

Can you verify this as fact? Or are you not certain?

Personally I know of no tests that prove consciousness causes the collapse. They all use an instrument to make the measurement and it is the instrument that causes it.

So why do so many believe consciousness plays a part?

 

[Rolfe]

If you don't chastise people for wearing certain clothes, or decorating their houses in certain ways, why should you chastise them for buying small bottles of water? He applied a similar argument to comparing the suppliers of homeopathic remedies, with the suppliers of fashion clothing, cosmetics and the like.

Supplemental, Friday.

This sort of touchy-feely rationalisation of homoeopathy as a harmless lifestyle choice is disturbingly common. Anyone who is tempted to go along with it should read today's Commentary.

I recently had a client approach me regarding the death of her 6-year-old daughter. This girl had been diagnosed with leukemia about a year before her death. .... She (the mother) claimed that during her daughter's treatment she came across a book written by a "Homeopathic" practitioner. This book claimed that chemotherapy was, in fact, the cause of most cancer patient's problems, and not the cure. .... the mother took her daughter off all of her medications and refused any further chemotherapy treatment. .... The little girl died shortly thereafter, from what the mother described as a lack of nutrition and over-medication. The mother wanted to sue the doctors for making her daughter sick with chemotherapy and failing to treat her per her own recommendations.

Read the full article, it's heartbreaking. It isn't all harmless placebos being dispensed by kindly quacks to competent adults who don't have anything serious wrong with them, not by any means.

Another quote:

To her (the mother), modern medicine was a conspiracy, and homeopathic medicine was the truth that it sought to undermine.

This is a viewpoint frequently propounded by homoeopathy, and it's just frightening.

I would even take issue with Randi's remark at the end, that "Most homeopaths, in my experience, are genuinely taken in by the nonsense, and convince themselves that it works, despite the contrary evidence." Regarding the ones who are qualified medics and vets, just how far can wilful refusal to look at that evidence go before it becomes deception? And regarding the lot of them - if the basic theory on which their entire edifice rests is true (the proposition that these solute-free preparations cause recognisable symptoms in healthy individuals, what they call a "proving"), then any one of them (or even us) should be able to pick up the JREF million any time they like. Many of them know this. Many of us make a point of telling them exactly how at any possible opportunity. However, to date not one single one of these "genuine, convinced" loons has tried for the money, or even agreed to an informal "just between us mates" trial to see if they can actually tell whether what they've been given is a real remedy or a sham. Even though the assertion that they can is their strongest argument when challenged by sceptics.

I wish it was me who'd thought up the phrase "ducks like a quack"

By the way, thanks for your comments, Dancing David.

Rolfe.

 

[wipeout]

I believe the decoherent histories approach to quantum theory has made very real progress in eradicating quantum weirdness, if not the quantum weirdos.

Wave function collapse itself is actually a mathematical shortcut and not a physical effect, hence the reason it seems so strange but gives correct results. It's mathematical, not physical. And it's not necessary for the decoherent histories approach either.

I believe the measurement problem, EPR paradox, Hardy's paradox, Schroedinger's Cat and other alleged weirdness have been analysed and resolved by the recent work. No more consciousness-creates-reality, faster-than-light effects or simultaneously alive and dead cats. They're all gone for good.

I hope.

The decoherent histories approach (also called consistent histories) is local and agrees with relativity, is purely quantum mechanical and has no hidden variables, has nothing travelling backwards in time, and has no observers, human or otherwise.

In other words, it's sensible.

It was developed mainly by Robert Griffiths, Roland Omnes and the better known Jim Hartle (as in the famous Hartle/Hawking "wavefunction of the universe" work with Stephen Hawking) and the Nobel Laureate Murray Gell-Mann (as in quarks, eightfold way, strangeness, etc.).

Richard Feynman saw early work on it by Gell-Mann and Hartle and said he agreed with every word of it. I'm sure Stephen Hawking is well aware of it too, not just because it involves his friend and collaborator Jim Hartle but also because it was partly developed for quantum cosmology because the Copenhagen interpretation was inadequate for it.

It's obviously not just any old quantum theory with guys like Gell-Mann and Hartle working on it and other guys like Feynman and Hawking apparently not seeing anything wrong with it. Other accomplished scientists have been positive about it too.

Anyhow, a book on quantum theory that doesn't feature something about decoherent histories is out of date, so beware.

I only know of a few that even mention it, though. Murray Gell-Mann's book The Quark and the Jaguar and Roland Omnes' book Quantum Philosophy both have some nontechnical details of the approach, but are only partly about it and it's not that easy to follow. But as Omnes says, if it was easy to explain then it would be easy to understand and then it wouldn't have taken so long to fix it.

I really hope decoherent histories is the end for quantum weirdness. Or the weird bits that aren't necessary, anyhow.

 

[Interesting Ian]

I believe the decoherent histories approach to quantum theory has made very real progress in eradicating quantum weirdness, if not the quantum weirdos.

Wave function collapse itself is actually a mathematical shortcut and not a physical effect, hence the reason it seems so strange but gives correct results. It's mathematical, not physical. And it's not necessary for the decoherent histories approach either.

This "decoherent histories approach" is more promising than the idea that consciousness collapses the wave function? How so? If this is true then I'll be surprised, but I certainly would not believe that it makes sense to talk about a material world in abstraction from our sensory perceptions. Metaphysical nonsense I'm afraid.

 

[jj]

that consciousness collapses the wave function?

Who made up that whopper?

Unless you're asserting a random photon, rambling along its way, is somehow concious ...

Ridiculous as usual, Ian, ridiculous as usual.

 

[Interesting Ian]

Who made up that whopper?

Unless you're asserting a random photon, rambling along its way, is somehow concious ...

Ridiculous as usual, Ian, ridiculous as usual.

Well what else could do apart from consciousness?

 

[wipeout]

This "decoherent histories approach" is more promising than the idea that consciousness collapses the wave function? How so?

In decoherent histories, you don't actually need a collapse of the wavefunction in quantum theory at all, and so it avoids a lot of the related problems.

 

[hammegk]

In decoherent histories, you don't actually need a collapse of the wavefunction in quantum theory at all, and so it avoids a lot of the related problems.

To me it sounds like it may have some of its' own problems though .... can it be validated by experiment as different from predictive-with-observer QM?

http://www.math.rutgers.edu/~oldstein/papers/qts/qts.html

Tez, Stimpy, help!

(Or go ahead jj, tell us what it means. )

 

[Dancing David]

David, I always believed it was the interaction that caused the photon to be absorbed, and not observation or consciousness.

Can you verify this as fact? Or are you not certain?

Personally I know of no tests that prove consciousness causes the collapse. They all use an instrument to make the measurement and it is the instrument that causes it.

So why do so many believe consciousness plays a part?

Because they aren't taking thier meds!

I think that somebody used the term observation at soem point and it went on from there. They don't understand QW, they just want an excuse to believe they are right, I guess.

I am not a student of QM, so when I say that it is the interaction leading to an observation that causes the intersection of the wavefunction(they don't collapse), I am hedging my bets in case JJ,Taz or Zombie tell me I am wrong.

 

[Solitaire]

Where is the electron when it is in the discontinuous phase,
I mean what kind of place is that, or where is it?????

Even worse, what happens if it hits a virtual antielectron while in
the discontinous phase? That'd force a virtual electron to become
real somewhere else and really mess up the universe.

 

[Solitaire]

Well what else could do apart from consciousness?

Psuedotime

 

[epepke]

Because they aren't taking thier meds!

I think that somebody used the term observation at soem point and it went on from there. They don't understand QW, they just want an excuse to believe they are right, I guess.

As I think I pointed out, there is a lot of detritus left over from the days when QM was understood much more poorly than it is now. The concept of the observer is one of these ideas. It's a natural idea, because people set up experiments to observe things.

I am not a student of QM, so when I say that it is the interaction leading to an observation that causes the intersection of the wavefunction(they don't collapse), I am hedging my bets in case JJ,Taz or Zombie tell me I am wrong.

I am. A student of quantum behavior, that is. I've done some collaborations on visualizations of quantum chromadynamics and quantum chemistry.

The "collapse" of the wavefunction is an idea that comes from some interpretations of QM. It has a number of problems. One that I think hasn't been thought about nearly enough is that if the wavefunctions collapse, something about them must then again "de-collapse," because you can use the same electrons over and over again, and nobody's watching then.

The trouble is that there does not seem to be a way to distinguish between the interpretations. I've seen some suggestions, but so far, all the ones I've seen have been flawed.

I'm going, based on pure intuition and nothing else, for the coherence and decoherence idea, where coherence is a relative term, and everything in the universe is coherent to some degree, though possibly a degree that in many useful cases may be so slight as to be ignorable.

Some days, I feel that amplitudes are all that there are, that whether Schroedinger's cat is alive or dead in some absolute sense is a meaningless question, just that the state of the cat (alive or dead) has amplitudes that cohere with my perception of the cat (trying to scratch me or unusually stinky).

 

[jj]

Well what else could do apart from consciousness?

Perhaps you should study the field, Ian.

A photon here, a photon there, pretty soon you're talking a real light beam!

 

[jj]

The "collapse" of the wavefunction is an idea that comes from some interpretations of QM.

But I think "collapse" is just a way to say that a photon, say, "observed" an electron, so that the probabilistic path of both intersected THIS TIME.

It has a number of problems. One that I think hasn't been thought about nearly enough is that if the wavefunctions collapse, something about them must then again "de-collapse," because you can use the same electrons over and over again, and nobody's watching then.

Yup, on the other hand, if electrons, for example, just have the probabilistic properties described by Schroedinger (or something newer that hasn't hit the street yet, perhaps, no, I don't know of any such thing), there's no collapse, no big problem, it's just a question of an "observation" being an interaction between particles. The fact that a particle has interacted doesn't at all mean that it's not going to keep going in some direction. Given h, we don't even know exactly where it was going or where it is (take your choice) to some extent, of course, so we keep the probabilistic nature fully engaged even during the "observation".

Some days, I feel that amplitudes are all that there are, that whether Schroedinger's cat is alive or dead in some absolute sense is a meaningless question, just that the state of the cat (alive or dead) has amplitudes that cohere with my perception of the cat (trying to scratch me or unusually stinky).

(heh)

Schrodinger's cat doesn't bother me at all. The decision is "made" by the detected decay (and one must say "detected decay" not just "decay"). Spit happens. Our opening the box is just letting in a lot more particles and exposing the cat and his state to humans.

Let's not forget, for example, the cat already knows (briefly) (Ian, care to grab that one and run away with it? ), and the detector that detected the decay has either done so, or not.

And then there's the question of information leakage from the box, which also pollutes the question.

In my book the word "observation" should be replaced by "interaction of particles".

I'm not aware, still, of anything that invalidates this particular interpretation.


Oh, and have you digested QCED yet? I think it may offer another alternative to it all.

 

[wipeout]

To me it sounds like it may have some of its' own problems though .... can it be validated by experiment as different from predictive-with-observer QM?

I've heard it said that decoherent/consistent histories can't be directly validated by experiment as it makes no predictions different from well-known quantum mechanics. But it was never meant to, I don't think, or it maybe wouldn't really be quantum mechanics anymore.

What it does differently is give another way to arrive at the same results as other interpretations but without doing things like, for example, violating special relativity on the way to these results, and this is obviously preferable.

I've been trying to get my head around exactly what is going on in the decoherent histories interpretation of the EPR paradox and, ironically, not too far away from me is Griffiths' introductory textbook on the subject, Consistent Quantum Theory, and it includes an analysis of the paradox, but it's for my Xmas so I can't look at it. LOL!

However, I think the crucial difference that people can miss about decoherent/consistent histories and things like theEPR paradox is that particles have the measured properties before they are measured.

(That is, when the particles are measured along the same direction as agreed in advance.)

On his website, Griffiths uses an example of different coloured cards sent in envelopes to different cities. Open one envelope and see the colour of the card in one city and you immediately know the colour of the card in the envelope in the other city.

In his book, The Quark and the Jaguar, Gell-Mann uses an example of the mathematician Bertlmann's different coloured socks. See the colour of the sock on one ankle and you immediately know the colour of the sock on the other.

If they wanted to demonstrate the EPR paradox in the well-known way they would be talking of the colours being undetermined until the card or sock were looked at. They are clearly not doing this.

In both examples used, the arrangement of the cards or socks existed before measurement, after measurement and even if you never measure it at all, measurement here obviously being just looking at the thing.

This is the point I believe they are trying to get across. Like I said, the collapse of the wavefunction isn't a necessary part of decoherent histories and so I guess we might expect something else to be happening.

Griffiths has a question and answer page:

http://quantum.phys.cmu.edu/quest.html

For example, one can show that a properly constructed measuring apparatus will reveal a property that the measured system had before the measurement, and might well have lost during the measurement process. The probabilities calculated for measurement outcomes (pointer positions) are identical to those obtained by the usual rules found in textbooks. What is different is that by employing suitable families of histories one can show that measurements actually measure something that is there, rather than producing a mysterious collapse of a wave function.

And more from the same page, the coloured cards example I mention....

Colored slips of paper, one red and one green, are placed in two opaque envelopes, which are then mailed to scientists in Atlanta and Boston. The scientist who opens the envelope in Atlanta and finds a red slip of paper can immediately infer, given the experimental protocol, the color of the slip of paper contained in the envelope in Boston, whether or not it has already been opened. There is nothing peculiar going on, and in particular there is no mysterious influence of one "measurement" on the other slip of paper. The quantum mechanical situation considered by EPR is more complicated than indicated by this example in that one has the possibility of measuring more than one property of system A and also considering more than one property of system B. However, when one does a proper analysis, the conclusion is just the same as in the "classical" case of the colored slips of paper.

See what I mean? Removing wave function collapse seems to have removed the idea that an entangled particle gains its properties only when it is measured and then instantaneously transmits it to its distant partner.

I've seen some criticism by some people online that Gell-Mann must not actually understand things like the EPR paradox if he is making the claim that it is no different from just ordinary classical experience, but I think it's perhaps almost certain that people are unaware of this important point about the properties being there in advance of measurement and then are wondering what the hell Gell-Mann is on about.

Even though I'm only beginning to learn quantum mechanics, I know all this stuff because I decided, since the field seemed such a conceptual mess, I'd make sure I knew what was going on by finding out what very smart guys like Feynman and Gell-Mann thought first before I trusted anyone else.

 

[Peter Soderqvist]

A REPLY TO EPEKE AND WIPEOUT

Epepke wrote 11-15-2003 02:16 AM: The "collapse" of the wave function is an idea that comes from some interpretations of QM. It has a number of problems. One that I think hasn't been thought about nearly enough is that if the wave functions collapse, something about them must then again "de-collapse," because you can use the same electrons over and over again, and nobody's watching then. The trouble is that there does not seem to be a way to distinguish between the interpretations. I've seen some suggestions, but so far, all the ones I've seen have been flawed.

Soderqvist1: The moon is not there when I am not looking at it!
The Moon is a huge collection of quantum objects which spreads like a wave, though very sluggish because it is an average out phenomenon between theses quantum objects! And Consciousness collapses the wave function when we see the moon, consciousness transform this wave of possibility into actuality, and spreads again like a wave when we stop looking at it! I don't say it is truth, but it is a consistent interpretation, which is not yet testable! Amit Goswami is Professor of physics at the University of Oregon!

Consciousness and Quantum Measurement by Amit Goswami
The interpretational difficulties of quantum mechanics can be solved with the hypothesis (von Neumann, 1955; Wigner, 1962) that consciousness collapses the quantum wave function. The paradoxes raised against this hypothesis have now all been satisfactorily solved (Bass, 1971; Blood, 1993; Goswami, 1989, 1993; Stapp, 1993). There is, however, one question that continues to be raised: Is consciousness absolutely necessary for interpreting quantum mechanics? Can we find other alternatives to collapse and consciousness as the collapser? Some of these alternatives propose to modify quantum mechanics in a major way (for example, nonlinear theories); others are not philosophically satisfactory (for example, decoherence theories); still others invoke other questionable physical theories in order to make sense of quantum mechanics (Cramer's, 19; Penrose, 1994). But there are two theories, one due to David Bohm (19), and the other called the many worlds theory (Everett, 1957), that still attract a lot of adherents.
http://www.swcp.com/~hswift/swc/Summer99/goswami9901.htm

An Interview with Amit Goswami
http://www.twm.co.nz/goswintro.htm

I have read Goswami 's book, The Self-Aware Universe!
What do you say of his way of reasoning?

 

[Peter Soderqvist]

Wipeout wrote 11-14-2003 04:31 PM: Wave function collapse itself is actually a mathematical shortcut and not a physical effect, hence the reason it seems so strange but gives correct results. It's mathematical, not physical. And it's not necessary for the de-coherent histories approach either.

Soderqvist1: David Bohm has said in Paul Davie's book, The Ghost in The Atom, that the wave function is a nonlocal informational wave which as pilot tells faster than light the "classical particle" how it shall move about in space, and thus Einstein's relativity is only an statistical theory. Bohm' 's interpretation is testable according to John Gribbin 's book, Schrodinger 's Kittens, but not yet carried out! But on the other hand Paul Davies has said that, the wave is a mathematical equation, which compute where the "electron" is most likely to be found! Just as a wave of crime in New York City has probabilities for felonies, since there the distortion or amplitude is as highest, there is the highest probability for a crime, or felony too!

I only know of a few that even mention it, though. Murray Gell-Mann's book The Quark and the Jaguar and Roland Omnes' book Quantum Philosophy both have some non-technical details of the approach, but are only partly about it and it's not that easy to follow. But as Omnes says, if it was easy to explain then it would be easy to understand and then it wouldn't have taken so long to fix it.

Soderqvist1: I have both these books in my bookcase, and I am reading for the moment The Quark and the Jaguar, Part Two- Quantum Universe, page 176 Swedish translation! His Many History Interpretation is very interesting; I am just in the beginning of his exposition!

11-15-2003 11:56 AM: However, I think the crucial difference that people can miss about decoherent/consistent histories and things like the EPR paradox is that particles have the measured properties before they are measured.

Soderqvist1: Measured properties before measured?
I think you mean properties are there before measurement!
How is that reality compatible with violation of Bell's inequality theorem?

On his website, Griffith 's uses an example of different colored cards sent in envelopes to different cities. Open one envelope and see the color of the card in one city and you immediately know the color of the card in the envelope in the other city.

Soderqvist1: this is only two colors, Alain Aspect 1982 used "triplets of colors", triplets of angular momentum! A "two color" experiment is pointless since we already know the answer; we simply need triplets in the experiment!

 

[Rolfe]

We seem to have some new participants in this thread who can at least persuade me that they know what they're talking about. Can I therefore repeat my request to have a look at a couple of pseud papers where QM is invoked as a mechanism of action for homoeopathy, and see if you can describe in a form comprehensible to the layman just why these authors are full of it? Dancing David already had a look, but the more the merrier, y'know.

Weingärtner, What is the therapeutically active component of homeopathic potencies?

Milgrom, Patient-practitioner-remedy (PPR) entanglement. (This is the first of a series of three papers, but one is probably enough.)



Would the "decoherent histories" approach nix their case if it was universally accepted? (What am I saying? They don't have a "case". They have demented fantasies. Maybe nothing will ever nix demented fantasies.) Still, it would be nice to be able to say something sensible if anyone ever calls me on my assertion that their maunderings are based on "a misunderstanding and misapplication of quantum theory".

Rolfe.