Can thinking about collapsing a wave form bring about measurement in quantum mechanic

maninasia

I understand that to collapse a wave function and pin down the state of a particle in quantum mechanics you need to make an observation. Traditionally I took that to mean light is shone on the particle and that the measurement is caused by the light waves interacting with the wave.

But recently I heard some scientists think it may be possible to collapse the wave by just thinking about it, is this possible?

http://discovermagazine.com/2009/feb/13-is-quantum-mechanics-controlling-your-thoughts

'Physicists describe quantum reality in an equation they call the wave function, which reflects all the potential ways a system can evolve. Until a scientist measures the system, a particle exists in its multitude of locations. But at the time of measurement, the particle has to “choose” just a single spot. At that point, quantum physicists say, probability narrows to a single outcome and the wave function “collapses,” sending ripples of certainty through space-time. Imposing certainty on one particle could alter the characteristics of any others it has been connected with, even if those particles are now light-years away. (This process of influence at a distance is what physicists call entanglement.) As in a game of dominoes, alteration of one particle affects the next one, and so on.'

Then this article talks about collapsing of the wave.

http://io9.com/5528321/how-smart-do-you-need-to-be-to-collapse-a-wave-function

It seems it's not clear how waves collapse and therefore what constitutes an observation, although I believe it's mostly an interaction with an atomic scale particle or chain of particles.

Professor_Fink

maninasia wrote: »

Traditionally I took that to mean light is shone on the particle and that the measurement is caused by the light waves interacting with the wave.

But recently I heard some scientists think it may be possible to collapse the wave by just thinking about it, is this possible?

That isn't what happens. The quantum classical transition is explained entirely by decoherence, and there has never been any evidence for collapse. What would appear to happen is that the system interacts with the environment, leading to an entangled state. When only part of the state is accessible, certain phases are ill-defined (as the system really cannot be properly described by a pure state of the reduced system). This results in what looks like stochastic behaviour (though I won't argue about whether it fundamentally is or isn't).

There is absolutely no way in which thinking about a system can make the wave-function collapse, as should be clear from the above. Anyone who says otherwise is simply ill informed.

maninasia

Professor Fink, you make dogmatic statements but then you state 'what appears to happen is....'

I think you should admit that the issue is unresolved on how the system interacts with the environment. You say there is 'no way' yet it is not known how the system interacts with the environment, from my reading of the subject.

There is also 'no way' the spin of two entangled particles should be able to react instantenously to each other...yet they do!

Professor_Fink

maninasia wrote: »

Professor Fink, you make dogmatic statements but then you state 'what appears to happen is....'

I think perhaps you misunderstand me. The mechanism for decoherence is well understood. That is exactly how we know how to create decoherence free subspaces and how to do dynamic decoupling. These have been experimentally realised many times, and in fact dynamic decoupling of H nuclei is a standard technique in NMR.

I hedged with the 'what appears to happen...' as regards collapse of the wave function, since while there is absolutely no evidence for this happening, the Copenhagen interpretation of quantum mechanics does allow for collapse, while the Everett interpretation does not, and this really isn't an issue of interpretations.

maninasia wrote: »

I think you should admit that the issue is unresolved on how the system interacts with the environment. You say there is 'no way' yet it is not known how the system interacts with the environment, from my reading of the subject.

We know exactly how many systems interact with the environment: You have relatively long range dipole-dipole interactions, short range exchange interactions, spontaneous emission of photons, Zeeman splittings and Lamb shifts due to environmental fields, phonon bath couplings, etc. etc. etc.

There are many ways in which systems can interact with the environment, and these depend strongly on the composition of the system and the composition of the environment.

maninasia wrote: »

There is also 'no way' the spin of two entangled particles should be able to react instantenously to each other...yet they do!

No they don't. There is a preserved quantity in the measurement outcomes which leads to a stronger set of correlations than possible within a hidden variable theory, but it doesn't imply any kind of instantaneous change. It simple says that you will always get correlations in measurement results.

I guess from the rather adversarial tone you have taken that you are trying to make me look stupid. That would be a mistake given that I know more about this topic than essentially anything else.

Professor_Fink

maninasia wrote: »

Professor Fink, you make dogmatic statements ...

As regards my statements, I can provide either mathematical proofs or very strong experimental evidence for everything I have said.

maninasia

And I'd guess sometimes you can't see the wood for the trees. No-ones doubting your understanding of this subject, what I doubt is that the subject is well understood! Parts of it are well understood, but then again atomic theory and how the table of the elements was constructed was well worked out when quantum mechanics came along.


Now take this statement-
'No they don't. There is a preserved quantity in the measurement outcomes which leads to a stronger set of correlations than possible within a hidden variable theory, but it doesn't imply any kind of instantaneous change. It simple says that you will always get correlations in measurement results.'

Is there anyway you could put it in plainer English? There seem to be hugely varying interpretations of what is going on here. From an observer's standpoint these entangled changes have been seen to operate at least at huge multiples of the speed of light and perhaps instantaneously. They seem to negate the effects of space and time in our classical sense. Unless they have been pre-programmed from the start, however it seems most scientists in this area don't lean towards this interpretation.

I have seen in my own area of expertise in another area of science dogmas getting trashed time and time again, especially when the dataset is narrow, tools are rough and general understanding of the subject is poor.

Professor_Fink

maninasia wrote: »

And I'd guess sometimes you can't see the wood for the trees. No-ones doubting your understanding of this subject, what I doubt is that the subject is well understood! Parts of it are well understood, but then again atomic theory and how the table of the elements was constructed was well worked out when quantum mechanics came along.

Fair enough, I won't take offense then. But I'm afraid I have to correct you on some points. First off quantum theory is very well understood. We have a concrete mathematical theory based on several postulates. Decoherence is well understood, though the mechanisms are dependent on the particular physical system being considered.

Atomic theory was not understood at all before quantum mechanics. There was no satisfactory explanation for atomic spectra, or even why there should be discrete spectral lines.

maninasia wrote: »

Now take this statement-
'No they don't. There is a preserved quantity in the measurement outcomes which leads to a stronger set of correlations than possible within a hidden variable theory, but it doesn't imply any kind of instantaneous change. It simple says that you will always get correlations in measurement results.'

Is there anyway you could put it in plainer English? There seem to be hugely varying interpretations of what is going on here.

This is not a philosophical question. Philosophers like to agonize over local realism, etc., but I assume you want to talk about the physics rather than the philosophy.

Putting it in plain English is hard, because quantum mechanics is a mathematical theory, and it is impossible to express accurately without relying on mathematics. I think this is what gives rise to the idea that physicists don't understand what is going on. We do, it's just hard to explain to someone who doesn't know anything about the subject because the theory is built on hundreds of years of progress in both mathematics and physics of which the vast majority of people are ignorant, and explaining all the building blocks takes a large chunk of an undergraduate course. Trying to squeeze this in over cocktails is therefore impossible. So you end up giving people an extremely dumbed down, analogy based approximation to the theory, which breaks down in many places. This is just as true of full length pop-sci books as it is of shorter pieces, interviews or discussions. This is why after reading many pop-sci books on quantum mechanics you will still not be able to calculate the spectrum for Lithium.

I will, however, attempt to explain this better. I take it you know what correlations are? Imagine I choose a card at random from a deck of cards, tear it in half and send both halves to different people (Alice and Bob). The state of the system can be described as a classical probability distribution with 52 possibilities for the card chosen, so the probability of either party revealing a particular card is exactly 1/52 (assuming I shuffled well). There is however a correlation between the two bits of card, however. The both must match. Looking at one card does not alter the state of the other card. It simply reveals to you which random state the card was in, and you can infer from the correlation the state of the other card, but you can certainly not alter it. So the correlation here is a conserved quantity of the state. No matter what the state of the two bits of cards, we know that they both must match.

The difference with entanglement is that correlations in quantum mechanics can potentially be stronger than in the classical world, but ultimately the same phenomenon is occurring. Imagine only two possible cards, labeled A and B. We take the measurement operator Z_i to result in +1 for the 0 state on the ith piece of card and -1 for the 1 state.

Clearly in the classical case we always have the correlation Z_1 * Z_2 = 1, since either both result in +1 or both in -1.

Now imagine the card is quantum mechanical, so we can prepare a superposition of it. Clearly if we tear it in two the two halves have to match when measured, so the classical correlation above is preserved. Imagine the superposition is 1/sqrt(2)((state 0) + (state 1)). When torn in two it becomes 1/sqrt(2)((state 0)(state 0) + (state 1)(state 1)). It is easy to confirm the ZZ condition from earlier still holds. However, note that if we have an operator X_i which flips the state of a single piece of card from 0 to 1 and 1 to 0, that applying X_1 and then X_2 results in the same state. This is equivalent to measuring in a different basis: determining locally whether each piece of card is in the state 1/sqrt(2)((state 0) + (state 1)) or 1/sqrt(2)((state 0) - (state 1)). So this is different measurement, so we obtain the additional correlation X_1 * X_2 = 1 (because applying one then the other keeps the state the same). These two correlations represent a maximally entangled state. If Alice and Bob choose to measure in either X or Z they will obtain the same result provided they both measured in the same basis. This is absolutely nothing to do with collapsing wave functions or signaling, or anything of the sort. It is simply that the two card pieces have a special correlation.

One last comment on this, because X_i*Z_i = - Z_i*X_i this means that there is an uncertainty relation: measuring one destroys any information about the outcome of the other measurement, so you never get to know what would have been. (This is important as it avoids any possibility of a paradox).

maninasia wrote: »

From an observer's standpoint these entangled changes have been seen to operate at least at huge multiples of the speed of light and perhaps instantaneously. They seem to negate the effects of space and time in our classical sense. Unless they have been pre-programmed from the start, however it seems most scientists in this area don't lean towards this interpretation.

No, they haven't. Actually the experiments you refer to are violations of Bell's inequalities (essentially measurements of these correlations). The entire point of separating the qubits and then making simultaneous measurements is to prove that a signal cannot pass between them (it is one of three possible loopholes). Actually the statistics of the experiments are used to prove that they cannot have been pre-programmed at the start. That is the whole point. They disprove a "hidden variable" model.

The point is that there is no effect passing from one place to another, it is simply a property of the correlations that certain measurement outcomes must match up, just as with the case of the cards classically. It is simply that these new quantum correlations allow for different statistics than can be possibly accomplished with classical correlations (which is how they disprove the pre-programming).

maninasia wrote: »

I have seen in my own area of expertise in another area of science dogmas getting trashed time and time again, especially when the dataset is narrow, tools are rough and general understanding of the subject is poor.

Theoretical physics isn't like other areas of science. It is by far the most fundamental and results within it take the form of mathematical theorems based on a very small number of postulates, which are then compared with experiment to determine the validity of the postulates. There isn't room for dogma in the way you suggest.

I will happily admit that there is almost certainly some dogma as regards what mathematics should be used to tackle which results, though I can't really think of any at the moment, but these do not alter the validity of the results. A theorem is a theorem, no matter how it is proved.

craggles

I admire your persistence, Professor Fink.

maninasia

Thanks for the detailed post, that's helped me out a lot, much appreciated. I have to read up on a few things.

Regarding this statement below, I couldn't agree with it myself, there are too many unknowns in how the universe was created, string theory, many world theory etc. Some of those unknowns could throw your experimental results way out of whack, or at least point to the large gap in knowledge that exists. A bit like the way Newton has his 3 laws worked out, but when relativty came along it showed us, literally, a whole new dimension to our universe. Also, your experimental results depends on a) what you are looking for b) how well your experiment is setup c) what tools you have on hand d) your objectivity
e) timing and location and other variables that you try to limit but may be impossible e.g. say you had a rare particle that only passed through the earth once in a hundred years, well you could have everything else ready but you would have to wait for that particle to arrive to really prove it's existence or not! If you research theories behind earthquakes you will see they have this exact same problem, huge gaps in knowledge due to limited dataset, events occuring longer than our historical timescale


- 'Theoretical physics isn't like other areas of science. It is by far the most fundamental and results within it take the form of mathematical theorems based on a very small number of postulates, which are then compared with experiment to determine the validity of the postulates. There isn't room for dogma in the way you suggest.'

Professor_Fink

maninasia wrote: »

Regarding this statement below, I couldn't agree with it myself, there are too many unknowns in how the universe was created, string theory, many world theory etc.

Many worlds is simply a philosophical interpretation of quantum mechanics. It doesn't change anything (other than reducing the total number of axioms).

String theory -is- a quantum field theory. Neither contradict quantum mechanics. In fact, any post-quantum theory will have to match quantum mechanics on the scales we have tested QM, just as quantum mechanics and relativity both match up with Newtonian mechanics in the regime it had been tested prior to the late 19th century.

I don't think it is necessarily easy to appreciate, but quantum mechanics is a spectacularly accurate theory, on a scale completely unknown in any other science. By this I mean quantum electro-dynamics makes predictions measured to be correct up to 12 significant digits. Show me any other science that has even come close to that level of accuracy. Fundamental physics simply is not like other subjects.

maninasia wrote: »

Some of those unknowns could throw your experimental results way out of whack, or at least point to the large gap in knowledge that exists. A bit like the way Newton has his 3 laws worked out, but when relativty came along it showed us, literally, a whole new dimension to our universe. Also, your experimental results depends on a) what you are looking for b) how well your experiment is setup c) what tools you have on hand d) your objectivity
e) timing and location and other variables that you try to limit but may be impossible e.g. say you had a rare particle that only passed through the earth once in a hundred years, well you could have everything else ready but you would have to wait for that particle to arrive to really prove it's existence or not! If you research theories behind earthquakes you will see they have this exact same problem, huge gaps in knowledge due to limited dataset, events occuring longer than our historical timescale.

Quantum mechanics is a fundamental theory in the sense that it underlies everything. It is fundamentally different from emergent phenomen (like earth quakes), and so is studied in a very different way. I am not saying that it must be correct, simply that it has a far stronger theoretical underpinning than other sciences, in that it is based on postulates that have been verified on a scale unknown outside of fundamental physics.

Also, it explains everything you have ever seen or ever will see.

maninasia

So you are saying quantum mechanics is the absolute fundamental unit of physics theory..then why can't there be a unified theory? In addition you must admit that their are many unknown parts still in quantum mechanics, we can't exactly reach the Planck energy to test them. We don't know how many 'layers' of particles even exist, is there a limit?

Another issue, assuming something is very accurate because of number of digits is a MASSIVE mistake, simply because we don't know where other phenomena suddenly pop up , such as the effects of relativity are only obvious on gravity with specialised tools (satellites) or events (Venus eclipses). Before general relativity nobody knew to look at eclipses of Venus more closely, when we knew what to look for it was patently clear Newton's theories could not explain what we could see! Quantum mechanics may explain everything we can see but maybe only because we don't know what to look for and we don't have the tools to look deeper.

Also the choice of number of digits for level of precision is entirely ARBITRARY, dependent on the observers own satisfaction of measurement and limits of his tools. Your scale might be good in relation to other 'emergent' phenomena, yet may still be completely inaccurate compared to reality!

This is the part that I find curious..time and again scientists have been proven to have an incomplete understanding yet the latest generation continues to make assumptions according to their worldview. As I also come from a scientific background, I am very suspicious of the word fundamental.

Professor_Fink

maninasia wrote: »

So you are saying quantum mechanics is the absolute fundamental unit of physics theory..then why can't there be a unified theory?

Quantum mechanics is assumed to be fundamental to the universe. It has been tested far beyond any other theory. Quantum field theories, string theory and quantum gravity theories are all fundamentally quantum mechanical. The fact that general relativity doesn't match up well with quantum theory is simply a sign that either quantum mechanics or general relativity are not a correct description of the universe, and the fault is most likely with GR. This says nothing about how fundamental the theories are, simply about whether or not they are correct.

maninasia wrote: »

In addition you must admit that their are many unknown parts still in quantum mechanics, we can't exactly reach the Planck energy to test them. We don't know how many 'layers' of particles even exist, is there a limit?

No I don't, because what you have said is nonsensical. We have a mathematical theory we call quantum mechanics, which describes the dynamics of systems. This takes as an input the Lagrangian of the system, which we have had to infer from measurements at particle colliders. Reaching the planck energy has nothing to do with learning new things about quantum mechanics, and is only tangentially connected to determining whether the mathematical theory (quantum mechanics) we have is correct or not.

maninasia wrote: »

Another issue, assuming something is very accurate because of number of digits is a MASSIVE mistake, simply because we don't know where other phenomena suddenly pop up , such as the effects of relativity are only obvious on gravity with specialised tools (satellites) or events (Venus eclipses). Before general relativity nobody knew to look at eclipses of Venus more closely, when we knew what to look for it was patently clear Newton's theories could not explain what we could see! Quantum mechanics may explain everything we can see but maybe only because we don't know what to look for and we don't have the tools to look deeper.

That is again nonsense. The difference between Newtonian gravitation and general relativity can be measured in pretty much any setting if you measure to sufficient accuracy.

maninasia wrote: »

Also the choice of number of digits for level of precision is entirely ARBITRARY, dependent on the observers own satisfaction of measurement and limits of his tools. Your scale might be good in relation to other 'emergent' phenomena, yet may still be completely inaccurate compared to reality!

I don't know how to argue with you. This is simply not true. Name to me any theory from any field other than theoretical physics which can make predictions of natural phenomena to an accuracy of one in a trillion.

maninasia wrote: »

This is the part that I find curious..time and again scientists have been proven to have an incomplete understanding yet the latest generation continues to make assumptions according to their worldview. As I also come from a scientific background, I am very suspicious of the word fundamental.

I think perhaps you are making a mistake in comparing our understanding of any other phenomena with our understanding of fundamental physics. The difference between earth science or geology or biology and quantum field theory is so large as to make them incomparable. Saying 'I'm a scientist too' just doesn't cut it. The areas of expertise between fundamental physics and any other field differ so dramatically there is little in common.

maninasia

You conveniently ignored many things I have stated here. For example the limitations of tools, the accuracy requirement. The requirement to even to start to know what to look for.

Recently there have been observations made that the Voyager spacecraft is not following the expected path that it should be by current theories of general relativity, it is off by a tiny but measurable amount. This in only detectable by the latest tools at scientists disposal. After detecting this, scientists are forced to remodel the theory. Ultimately if it cannot be remodelled it must be replaced.

As you must know, higher energies are required to fully explore the quantum world (or family of particles), if you can't reach those energies you don't know what is really happening beyond the current limitations of synchroton colliders.

The fact that something can be measured to 1 in a trillion means nothing at all! It's all relative if the effect to be observed is 1 in a quadrillion for example.

I think you have to open your mind to these issues.

I don't think that quantum mechanics is more fundamental than other sciences or somehow superior. You are making an artifical distinction. It is just science at a different scale. You are allowing your observer bias to get in the way and write off my comments too quickly. There may be more fundamental layers that we don't know about yet.

sponsoredwalk

maninasia wrote: »

Before general relativity nobody knew to look at eclipses of Venus more closely, when we knew what to look for it was patently clear Newton's theories could not explain what we could see! Quantum mechanics may explain everything we can see but maybe only because we don't know what to look for and we don't have the tools to look deeper.

I think this is a misreading of whatever source your basing this on. Astronomers knew of the discrepancies in Newtonian calculations regarding Mercury & Venus but had no theory to account for it. Also, Einstein knew what value he was looking for with regard to this aspect of GR.

You may have already seen all of these links but I'll give them to you anyway, all are to do with QM & it's predictions.

http://vega.org.uk/video/subseries/8 (worth being watched first!).
http://research.microsoft.com/apps/tools/tuva/index.html
http://boulder.research.yale.edu/Boulder-2008/public_lectures2008.html Realplayer movie file (Ramamurti Shankar of 'Principles of Quantum Mechanics' fame!).
http://www.youtube.com/user/cassiopeiaproject
http://bethe.cornell.edu/index.html

Then if you are able to foray into the world of vector calculus & linear algebra:

http://www.youtube.com/watch?v=0Eeuqh9QfNI&feature=channel

with string theorist Leonard Susskind (find out online about the 8 or so courses he has online!).

Also, I don't know what you're arguing for? I can only guess this is coming from the 'What the Bleep Do We Know' movie or something I think you misunderstand the use of 'quantum mechanics'. Qft, qcd, the standard model etc... are all quantum mechanics in that qm is fundamental to all of them. You postulating that there is something more fundamental is about as helpful as telling us invisible angels secretly push the planets.

Nobody has ruled out anything in this thread & you're just arguing with your own lack of understanding.


Also, as regards GR discrepancies: nobody has claimed GR was perfect.
It has a few anamolies but I hate it when people make bold claims like;

maninasia wrote: »

You are allowing your observer bias to get in the way and write off my comments too quickly.

when they are clearly describing themselves because the evidence is always in black & white on the very page.

Professor_Fink wrote: »

The fact that general relativity doesn't match up well with quantum theory is simply a sign that either quantum mechanics or general relativity are not a correct description of the universe, and the fault is most likely with GR. This says nothing about how fundamental the theories are, simply about whether or not they are correct.

:rolleyes:

How did your lack of observer bias miss that one?

Professor_Fink

maninasia wrote: »

You conveniently ignored many things I have stated here. For example the limitations of tools, the accuracy requirement. The requirement to even to start to know what to look for.

It's simple: you start by calculating a particular observable from your mathematical model, you then measure it as precisely as you can, and then you compare your results. Any deviation indicates a potential problem with your model. Any incorrect model will almost certainly deviate in its predictions at a high enough level of precision. And in this case "almost certainly" means with probability 1, as the set of possible measurements which don't yield any difference is a subset of measure zero of all possible measurements.

Limitations of tools play no role in this: If your tools are inaccurate you can never achieve the desired level of accuracy, and so know that you cannot decide between theories which make predictions which differ by much less than this.

maninasia wrote: »

Recently there have been observations made that the Voyager spacecraft is not following the expected path that it should be by current theories of general relativity, it is off by a tiny but measurable amount. This in only detectable by the latest tools at scientists disposal. After detecting this, scientists are forced to remodel the theory. Ultimately if it cannot be remodelled it must be replaced.

No, in practice they are stuck in the position of figuring out where their model went wrong. While it is possible that it is a flaw in relativity that causes it, it seems far more likely to be a problem with their estimation of the factors influencing the trajectories, and they get stuck trying to rule those out. Ultimately however, if they come up with some new physics that explains this anomaly, which is cannot be expressed within the framework of general relativity, then we have some new theory which is most definitely NOT general relativity. It would be incorrect to say that such an anomaly means we don't understand general relativity. To say so is to misunderstand what a theory is in theoretical physics.

maninasia wrote: »

As you must know, higher energies are required to fully explore the quantum world (or family of particles), if you can't reach those energies you don't know what is really happening beyond the current limitations of synchroton colliders.

Again, I think you are misunderstanding what quantum mechanics is. It is a mathematical theory. It is not purely by definition how small stuff works. It is simply the case that our mathematical model matches with observations to a level never before achieved in any field of science.

maninasia wrote: »

The fact that something can be measured to 1 in a trillion means nothing at all! It's all relative if the effect to be observed is 1 in a quadrillion for example.

Indeed. Now, can you name a theory that has yielded such accurate predictions? No? That's because quantum mechanics is the most accurate mathematical model for the universe that we have ever had.

maninasia wrote: »

I think you have to open your mind to these issues.

I don't think that quantum mechanics is more fundamental than other sciences or somehow superior.

It is. It is simply the most accurate model we have ever had of any natural process.

maninasia wrote: »

You are making an artifical distinction. It is just science at a different scale. You are allowing your observer bias to get in the way and write off my comments too quickly. There may be more fundamental layers that we don't know about yet.

I'm not sure there is much more I can say about this. Quantum mechanics isn't a layer. It is a fundamental mistake to think that the world is build up in layers that are independent of each other. It is a set of principles which governs everything you have ever seen or ever will see. Such a thing can only be said of physical theories. For example chemistry does not underlie everything, since there are some things (photons, mesons, etc.) which are not chemical. Equally biology is studies things which are made out of molecules, but biology bares no relation to the study of metalurgy, for example.

I am certainly not saying this to rile up people from other fields, and I am not saying that work in any one field is worth more than another. I am simply saying that analogies from other sciences often cannot be applied to the study of fundamental physics. It is the one science where we are specifically not classifying emergent phenomena (though of course there are areas of physics which do so). Particle physicists are extreme reductionists in a way unknown to other field of science (though it may look more familiar to mathematicians and philosophers).

maninasia

I enjoy debating these points with you, even if most people don't seem to be interested by these questions. I don't think we can agree on some of these points but that's fine.
The problem with mathematical theories is just that, they are mathematical constructs and sometimes not representative of the true situation. You need the tools and technology and insights to know where to look to 'prove' these theories.
I know it is artificial to make a barrier between quantum and atomic and chemical and biological laws. They do indeed depend on physical properties, yes properties do 'emerge' from them. However the quantum properties may also 'emerge' from yet another layer further down... and so on. Mathematics on its own cannot give all the answers.

Professor_Fink

maninasia wrote: »

The problem with mathematical theories is just that, they are mathematical constructs and sometimes not representative of the true situation.

I certainly agree that this is the case, though for fundamental physics most mathematical models aim to be perfect descriptions of the system, which is unlike any other area where models rely on certain assumptions and approximations about lower level phenomena.

A nice example of this is indistinguishable particles: All electrons are identical. We know this because of, among other things, the observation of an exchange interaction, and because they obey Fermi-Dirac statistics. This rules out the possibility of different electrons having different internal structure. The same is not true in more complex systems. No two organisms are identical, not even all molecules are identical due to the natural abundance of isotopes.

maninasia wrote: »

You need the tools and technology and insights to know where to look to 'prove' these theories.

No. You can't prove a scientific theory, you can only gain evidence for the applicability of the model, which increases your confidence that it is an accurate description of the universe.

maninasia wrote: »

I know it is artificial to make a barrier between quantum and atomic and chemical and biological laws. They do indeed depend on physical properties, yes properties do 'emerge' from them. However the quantum properties may also 'emerge' from yet another layer further down... and so on. Mathematics on its own cannot give all the answers.

No, they don't. Quantum mechanics is not a theory about structure, it is a theory about dynamics. For example, cars are made of metal which is made of atoms which are made of electrons and nucleons. The nucleons are in turn made up of 3 quarks each. Could there be something beyond quarks? Maybe. But all levels of this obey the same dynamical laws. All of them can be accurately modeled by the Schroedinger equation, it's just impractically hard to solve for complex systems, as the number of dynamic parameters increases exponentially with size.

Mathematics alone can and does give you all the answers about quantum mechanics, which consists of a set of postulates. Whether these postulates are justified or not is an entirely different question, and one which relies on experimental verification.