Fault lines in Theoretical Physics

[peter]

I had not realised that Schrodingers wave equation had divided the scientific community to an extent where to this day, some eighty years after it's publication it is still a scource of division in our understanding of 'how the world works'. I read Michio Kaku's explanation of why this is so in The future of the Mind but am still alas, not clear as to what the beliefs of the respective camps are in respect of this division. Also, I believe the far reaches of theoretical physics are somewhat divided as to the correctness or otherwise of 'string theory' as an answer to the paradoxes created by quantum theory. Lastly I'm not 100% clear on what is meant by 'the Copenhagen Interpretation' - or indeed what alternative interpretations exist either [although I do believe that Nils Bhor was the architect of this 'interpretation in his lab in Copenhagen, hence it's name.

Would it be a massive job to throw a little light on these areas [as simplistically as possible without totally destroying the content ] for me and also point out other places where there is significant disagreement as to the state of affairs at a fundamental level.

[Zarathustra]

The Copenhagen Interpretration is basically, "there is no deep reality." The phenomenal world is real, but it "floats" upon a quantum layer that isn't real in the same way. Electrons exist, but they don't have definite properties (position, momentum, etc.) until we measure them. Prior to that, they "smear" between all possible states with a certain probability of having definite values according to Schrodinger's wave equation.

One alternate interpretation would be the "many worlds" model, which states that every possible state for every particle actually exists, in another parallel universe. Each time we make an observation or measurement, we are splitting off the universe into one with those particular values.

Obviously, these are pretty extreme models of reality we're talking about here. But this level of extremity is necessitated by the wild, counter-intuitive facts of quantum mechanics. We know the theory is true, even though we're not sure how to understand it, or reconcile it with our commonsense experience of the world.

[Vraith]

I had not realised that Schrodingers wave equation had divided the scientific community to an extent where to this day, some eighty years after it's publication it is still a scource of division in our understanding of 'how the world works'. I read Michio Kaku's explanation of why this is so in The future of the Mind but am still alas, not clear as to what the beliefs of the respective camps are in respect of this division. Also, I believe the far reaches of theoretical physics are somewhat divided as to the correctness or otherwise of 'string theory' as an answer to the paradoxes created by quantum theory. Lastly I'm not 100% clear on what is meant by 'the Copenhagen Interpretation' - or indeed what alternative interpretations exist either [although I do believe that Nils Bhor was the architect of this 'interpretation in his lab in Copenhagen, hence it's name.

Would it be a massive job to throw a little light on these areas [as simplistically as possible without totally destroying the content ] for me and also point out other places where there is significant disagreement as to the state of affairs at a fundamental level.

I started writing something...and it started showing signs of being monstrous and beyond my control. So I killed it in favor of just a couple things:
On Copenhagen:
There exist other interpretations...
I don't know much about them other than that they solve certain problems/paradoxes/inconsistencies/incompletenesses inherent in Copenhagen, but can't come close to explaining or predicting on the scale demonstrated by Copenhagen. They can conjugate the verb "to be," but can't reveal Hamlet, explain Mermaids, but not tell the whole story. [].

String Theory is the most explored/examined [so far] "theory of everything." But physicists are more than just "somewhat divided."
It's pretty. It solves some problems.
#1 Unfortunately: so far, no actual testable predictions [lately a few different hints/suggestions of performable tests have been proposed...not that we can perform NOW, I don't think, but that we will be able too sometime relatively soon].
#2 Unfortunately: there are so MANY possible string theories. Even sorting them out a bit with M-theories you end up with GOOGOLS of possibilities.
There's other stuff, too. Here's a link with brief info on string and some of its competitors.

www.newscientist.com/article/dn18612-kn ... 2e9ePldW_Z

[SerScot]

Vraith,

#1 Unfortunately: so far, no actual testable predictions [lately a few different hints/suggestions of performable tests have been proposed...not that we can perform NOW, I don't think, but that we will be able too sometime relatively soon].

That's a big problem for any hypothesis offered in Science. Can the "String Idea" even be called a hypothesis as there is no way to test it?

[Vraith]

Vraith,

#1 Unfortunately: so far, no actual testable predictions [lately a few different hints/suggestions of performable tests have been proposed...not that we can perform NOW, I don't think, but that we will be able too sometime relatively soon].

That's a big problem for any hypothesis offered in Science. Can the "String Idea" even be called a hypothesis as there is no way to test it?

Yea, it is a big problem...and in earlier ages an absolute bar.
The problem with the problem NOW is we got here by demonstrated methods.

In a way, it is Quantum part 2. Lots of folk hated quantum. There is some evidence that folk prior to and simultaneous with but independent of Einstein and the birth of it [and the man himself certainly did] said "the math says...but that CAN't be, that is INSANE, and no one will EVER be able to show it in reality."
But the best of those ways of thinking ended up making predictions, being testable, and being proven...not just once, but more successfully than anything ever before in all of science.
Much of it happened pretty quickly in quantum...because hard as it is to believe quantum was a helluva lot easier. I mean, in a vastly oversimplified, step-skipping way, all you needed to BEGIN to test quantum was a stack of uranium. It seems we need a stack of universes to begin testing string and such. That's a big difference. [and might not be true....cuz....
It is a quandary...for NOW. But, like I said...hints are arising that the 'untestable" might very well BE testable. [one involves some measurements involving the solar system and orbits or some such thing] The big problem on the horizon is some way of sorting options cuz we just plain don't have the time, literally, to test every single one even when tests are available.
We need a "sorting hat."

[Hashi Lebwohl]

That's a big problem for any hypothesis offered in Science. Can the "String Idea" even be called a hypothesis as there is no way to test it?

I suppose they could use the word "conjecture" until someone comes up with a way to test it, at which point it can revert to "hypothesis".

In general, I concur with Copenhagen--at the quantum level there is no reality like we normally know it. Our mathematics and understanding are not yet sufficiently advanced to understand what is happening at that level but that is something which will change in the future. At some point, someone will make a breakthrough and we will understand what is really going on at the quantum level more completely and correctly; when that happens the scientific community will adjust its views accordingly and keep moving forward.

I don't think that when a waveform collapses and reality actualizes that it makes a difference to the universe as a whole--reality is localized. A supernova which happens 20 light years away is not going to alter the timing of the next lunar eclipse, for example, even though photon coupling apparently has no limitation of distance as we measure it--the effects are instantaneous, meaning that some sort of supraluminal communication or cause/effect phenomenon is happening. I suspect that photons are connected at one of the higher dimensions from string or M theory and that dimension does not have a cosmic speed limit or may not have a time arrow like we have here in our measly four dimensions.
Anyway....wild conjecture like that is what will lead to the next breakthrough and then the person who made the wild conjecture will have to spend the next 10 years trying to backtrack their experimental evidence via mathematics to connect it to all the proven math which came before.

[Zarathustra]

I suppose they could use the word "conjecture" until someone comes up with a way to test it, at which point it can revert to "hypothesis".

In general, I concur with Copenhagen--at the quantum level there is no reality like we normally know it. Our mathematics and understanding are not yet sufficiently advanced to understand what is happening at that level but that is something which will change in the future. At some point, someone will make a breakthrough and we will understand what is really going on at the quantum level more completely and correctly; when that happens the scientific community will adjust its views accordingly and keep moving forward.

It's not our mathematics that is lacking. We understand the quantum world mathematically better than any other theory humans have ever devised. We've also proven it empirically to a greater degree of accuracy than any theory in history.

The problem is that it seems to be at odds with our commonsense, macro-level, everyday undersanding of reality. So the problem lies with our commonsense understanding of reality, not our understanding of the quantum world. Evolution has given us a brain that uses approximations on a different level than what is strictly true.

I don't think that when a waveform collapses and reality actualizes that it makes a difference to the universe as a whole--reality is localized.

This is absolutely false:

Bell himself managed to dvise such a proof which rejects all models of reality possessing the property of "locality." This proof has since become known as "Bell's theorem. It asserts that no local model of reality can underlie the quantum facts."

...Bell's result does not depend on the truth of quantum theory. The Clauser-Aspect experiements show that Bell's inequality is violated by the facts. This means that even if quantum theory should someday fail, its successor theory must likewise violate Bell's inequality when it comes to explaining the twin state. Physics theories are not eternal. When quantum theory joins the ranks of phlogiston, caloric, and the luminiferous ether in the physics junkyard, Bell's theorem will still be valid. Because it's based on facts, Bell's theorem is here to stay.

[Vraith]

I mostly agree with your response to Hashi, Z. Our common sense...even our senses themselves...somewhat mislead us in the comprehensions of micro/macro. OTOH---there IS a real problem between the micro and macro that is not purely the result of being one-eyed in a blind kingdom.
There is undiscovered country between them...and we may be permanently stuck with [though able to refine] the maps and never directly know the territory.

The other part I think, over reaches. Locality seems forbidden in any UNIverse. But in a "reality" that is multi-versal? Not so sure...not in the way those wackos on the fringes thing of "local." I suspect any survivable -verse will have A quantum aspect, it needn't be OUR quantum, ours needn't be THE quantum...though they'll probably have a family resemblance.

[peter]

Fantasic response guys - you have my gratitude. Can I just drag it back to the simple level of 'cats in boxes' to try to ensure I got what Z. was saying in his first post.

If I understand it, on the one hand, you have the situation where Schrodingers cat is in the live/dead smeary state that collapses into one or the other on the act of making an observation. On the other [the many worlds hypothesis] the cat already exists in both the live state in one universe and the dead state in another. Here the act of observing will occur at a 'bifurcation' in which the observer will follow either the path leading to an observation of a live cat, or a path leading to the observation of a dead cat. [However the 'or' in the above sentence is in reality an 'and'. ie since both Universes exist, both results occur, but in each case the observer is only aware of the one that occurs in the particular Universe he experiences].

Strange, I got the idea from the book [perhaps erroniously] that Schrodinger actually proposed the cat thought experiment because he wanted to show the deep water that quantum theory had navigated theoretical physics into, rather than as an explanation of what was really going on. BUT - another book I read once said that every time you turned on a tv, or a transistor radio, you verified the truth of quantum theory, since just about all of the technology that has found its way into our homes over the last three decades is a direct descendant of that quantum universe revealed in the theory and if it weren't true none of it would work. I like that.

[Zarathustra]

If I understand it, on the one hand, you have the situation where Schrodingers cat is in the live/dead smeary state that collapses into one or the other on the act of making an observation. On the other [the many worlds hypothesis] the cat already exists in both the live state in one universe and the dead state in another. Here the act of observing will occur at a 'bifurcation' in which the observer will follow either the path leading to an observation of a live cat, or a path leading to the observation of a dead cat. [However the 'or' in the above sentence is in reality an 'and'. ie since both Universes exist, both results occur, but in each case the observer is only aware of the one that occurs in the particular Universe he experiences].

Sounds good to me.

Strange, I got the idea from the book [perhaps erroniously] that Schrodinger actually proposed the cat thought experiment because he wanted to show the deep water that quantum theory had navigated theoretical physics into, rather than as an explanation of what was really going on. BUT - another book I read once said that every time you turned on a tv, or a transistor radio, you verified the truth of quantum theory, since just about all of the technology that has found its way into our homes over the last three decades is a direct descendant of that quantum universe revealed in the theory and if it weren't true none of it would work. I like that.

Perhaps you're right about Schrodinger's reasonings. I think the same thing happened with Alan Turing's "Turing Test," it was originally proposed as a way to demonstrate just how hard the problem of AI is, and now people take it merely as a sufficient criterion to achieve AI or prove that you've achieved it. I think Einstein also proposed some thought experiments which were supposed to prove a reductio ad absurum on quantum mechanics, but then just ended up proving how absurd reality is, lending strength to quantum mechanics.

Anyway, you're right that one strong proof of quantum mechanics lies in the technology we build from it. However, we also send satellites to distant planets using Netwonian mechanics, so the proof isn't always in the application. However, if you can't build a working technology based on some theory or branch of science, especially the fundamental, physical sciences like physics/chemistry/biology, then you're talking philosophy or religion, not science. As I used to point out in evolution/creationism debates: no one has ever built anything using "creation science." That's one big clue that it's not really science, but religion masquerading as science.

[Hashi Lebwohl]

I don't think that when a waveform collapses and reality actualizes that it makes a difference to the universe as a whole--reality is localized.

This is absolutely false:

What I mean by "localized" is this--if some particle physicists run an experiment and make an observation of a subatomic particle, then the observation causes a collapse of that particle's waveform into reality. Regardless of the results of that collapse it won't change what you chose to have for lunch and it won't cause any wobble in the Moon's orbit. In general, changes way over there (this is me pointing at some distant location) have no effect on what happens right here.
It is true, of course, that at the quantum level there is no such thing as "localized" because the concepts we have such as "location" or "distance" or "time" have no meaning--two coupled particles which then happen to separate by a parsec still react as if they are next to or near to each other. It is almost as if "distance" at the quantum level (or one of those higher dimensions accessible only at the quantum level) involved complex numbers for distance, which isn't outside the realm of possibility since the dilation function allows for complex results once you go past c. If one particle is at (0, 0, 0, 0, 0) and another particle is at (1, 1, i, i, i,) then their distance is sqrt{sum[x_i - y_i]^2} or sqrt[1 + 1 - 1 - 1 - 1] = sqrt[-1] = i, which has no meaning to us in four dimensions but we see the distance as sqrt(2). *shrug* I think now I am rambling and that can't be a good thing.

[Avatar]

We are all agreed that your theory is crazy. The question that divides us is whether it is crazy enough to have a chance of being correct.

--A

[peter]

[ I did try to read your post Hashi - honest ]

re the Newtonian examples Z., would not everything explainable by Newtonian Mechanics also have to be explainable by the Relativity Theory that surpassed it - and then some. [So in other words the sending of satellites would have to be possible by relativistic calculation as well as Newtonian]. Does the quantum-relativity mutual exclusivity not mean that both theories are incomplete rather than either having to be wrong?

[Vraith]

[So in other words the sending of satellites would have to be possible by relativistic calculation as well as Newtonian].

Does the quantum-relativity mutual exclusivity not mean that both theories are incomplete rather than either having to be wrong?

On the first: if you had the processing power, I'm pretty sure you could do launches/calculations as you suggest.
But why bother? Cuz it is almost unimaginably more complicated, and the result would be exactly the same...or so close to identical as to be meaningless in difference. [now...if you were trying to launch a quantum-size satellite [especially into orbit from a black hole] that's a different story.

Quantum-relativity may, one or other or both, be "wrong" in a big way...but that seems extremely unlikely at this point.

Incomplete seems most likely...and it is possible that they will ALWAYS be incomplete.
That depends on...which in another thread, we've all chattered on, I think...in what way/in what effects is math real.

For instance, IF math in some manner "physically" affects the nature and shape of reality, then it is possible that the problems between quantum and relativity aren't the result of either one being wrong or incomplete...they are true. The problem is material reality is somehow inconsistent with itself.

HEY! MAYBE somehow the Big Bang was CAUSED by the fact that those extreme conditions make those inconsistencies manifest...so it all blows up. Gravity gets trapped in an intervention by the Force Family. And his response is "Look, y'all are family, I love ya...but ya can't just randomly mess around with my stuff. So just get the hell OUT of MY ROOM!"

[Orlion]

Quantum is probability. Due to the high energy and constant fluctuating motion of particles at the quantum level, it is impossible with any of our current instruments to measure position, momentum, etc. of a, say, electron like we can with a baseball. This leads to 'uncertainty' since we can not know the exact values. We can know generalities, though. We can know that, at a certain energy level, an electron is likely to be found in a certain space and we can apply that knowledge to predict things like whether molecules can create a molecular bond.

But it is really just applied probability. Saying a cat in a convoluted box experiment is both dead and alive until observed is like saying the top card of a shuffled deck is all 52 values of that deck until you flip it over to reveal as the seven of spades. It says more about our ability to observe then what is actually happening. That card was always the seven of spades, even if we didn't know it. There are not 51 other universes where the top card (in my example) is some other value.

[Vraith]

. Saying a cat in a convoluted box experiment is both dead and alive until observed is like saying the top card of a shuffled deck is all 52 values of that deck until you flip it over to reveal as the seven of spades. It says more about our ability to observe then what is actually happening.

Well...that SHOWS the problem, it doesn't disprove or answer it.
The cat...and your deck of cards...in "real" terms, on our scale are not quantum. It's just a matter of making a guess on the odds. The macro-physical is already in some state. Opening the box [on the macro] doesn't suddenly make the dead [or living] cat real...not does lifting the lid kill or save the cat. Flipping the card doesn't MAKE it become a particular card. We can't KNOW the answer until we look...but that doesn't mean the particular state doesn't exist.

The quantum is different. The mind-experiment just a path/analogy to try to understand the difference.

It is not a problem of "our" ability/methods of observation. It is a problem of "observation" itself AND "actually" itself AND "happening" itself. [also minus themselves and times themselves and in groups themselves]

[peter]

Of course you would never actually do the calculation that way V., but the point is surely that if the relativity 'paradigm' is going to surplant the Newtonian one it *has* to at least be able to do everything that that the surplanted paradigm could do - if it couldn't it would not be a replacement theory. [By the way discovered where your name came fron in the TC books the other night - love it!]

I thought the uncertainty was inherrent in the quantum system - ie that *no* instruments would ever be able to establish both position and momentum of [say] an electron no matter how good they were.

The second part of Orlion's post gets exactly to where I was going next - ie Are we suppused to take the live/dead [or indeed the two Universes] state as real at the macro level of the cat in the box, or was it just an illustration put in real size objects to help us understand what was happening to the electron down at the quantum level. If I'm getting it correct V., your follow up post goes for the second option.

[Vraith]

Of course you would never actually do the calculation that way V., but the point is surely that if the relativity 'paradigm' is going to surplant the Newtonian one it *has* to at least be able to do everything that that the surplanted paradigm could do - if it couldn't it would not be a replacement theory. [By the way discovered where your name came fron in the TC books the other night - love it!]

I thought the uncertainty was inherrent in the quantum system - ie that *no* instruments would ever be able to establish both position and momentum of [say] an electron no matter how good they were.

The second part of Orlion's post gets exactly to where I was going next - ie Are we suppused to take the live/dead [or indeed the two Universes] state as real at the macro level of the cat in the box, or was it just an illustration put in real size objects to help us understand what was happening to the electron down at the quantum level. If I'm getting it correct V., your follow up post goes for the second option.

Glad you like the name...
I'm pretty sure relativity CAN do everything Newtonian does...and certainly many things it can't. But on our scale Newton is just simpler and close enough for most things.

Yes, no instruments will ever be able to...that's kinda what I was getting at in my odd way. Instrument/observer is A problem. But it isn't the ONLY one.

My understanding is that some really deep arguments...beyond my real understanding...are about the "placement" of the uncertainty. If it is IN the things, or IN the interactions, and/or if there is a meaningful difference.

From what I've read, there is little doubt that the heavy hitters in the beginning and development considered the wave function to be theoretical/conceptual/subjective...to only "represent" the state. That's still the dominant view. But not the only one...IIRC, Heisenberg shifted toward the possibility it was "real" over the course of his work. [[he did...I just went and checked]]
My overall impression is there are quite a few who don't/haven't picked a "side"
...and some who think it just doesn't matter.
It might be more precise to say, on the last, that AFAICT what they're saying is:
"We can't, ever, decide that answer by looking at it directly.
We need to look past/beyond it. If/when we "get" THAT stuff, it will tell us the answer."

[peter]

That figures. If one side or the other was 'based on sand' then surely it would rapidly fail to support any subsequent predictions based on if they *could* be tested experimentally. If none of it could ever be tested, then it is metaphysics and not physics.

[peter]

Have been giving the 'Schrodingers Cat' thing a bit of thought and just wondered what the consequenses would be if he had followed it up with an appendix experiment - 'Schrodingers Post-Grad Student' in which the place of the disinterested and unobservant cat is replaced by a very interested and very observant [not to say nervous given the motivation] acolyte of the great man. Now we have to consider what the state of affairs is from the point of view of the student actually within the ....let's give him a sealed room in the lab shall we. How does he observe his live/dead smeary [or more simply many Universe state] - or for him, is it the outside world that in in it's 'uncollapsed state' - a smeary mix of observed/un-observed smudgyness in respect of the external observers. And what if instead of the perhaps deliberate element of 'uncertainty' that Schrodinger introduced into the design of his thought experiment [re the phial of toxic gas being triggered by the intrinsically uncertain decayed or not decayed state of a radioactive isotope] we remove that element of uncertainty and instead tell the student that his much adored girl-friend has buggered off with his flatmate - and then lock him in the room instead with a fully loaded semi-automatic? And what effect does the introduction of a two-way live cctv feed - or indeed one with a ten second delay feature - have on all of this.

Surely with these kinds of extensions, paradoxes that rule out the various options are demonstrated?