Cosmology, Quantum Mechanics & Consciousness Message Board › Electron Entanglement

Electron Entanglement

A former member
Post #: 2
Has anyone else seen the article "Strange and Stringy" in the (already out) January Scientific American? To quote from the summary : "The electrons that perfuse materials can undergo their own transitions, which involve inherently quantum properties of matter. These states arise from an unimaginably complex web of entanglement among the electrons" (e.g. in supercoduction). The author (field condensed matter) explains very clearly how electrons, usually anti-social fermions, "[can] become strongly entangled with one another, and can no longer be viewed as individual particles". This is not new, of course, but the author has for once found a use for string theory, not by applying it directly but by transposing it -- "those of us studying quantum states of matter can go to the library, look up a possible solution to a stringy situation and translate it....to the entanglement situation". He also introduced the (to me) new concept of a 'superfluid' "which is just like a superconductor except that it is electrically neutral....there is flow without any friction". But read the article, the author himself says he doesn't understand string theory and there is no mathematics in it as usual for Sci. American articles. Robert Mules
A former member
Post #: 185
Robert, I spotted that article on the web after you mentioned it, I skimmed some of it, and now I can't find it! So no, I haven't actually read it but I picked up that it was about a researcher using string theory maths to help with problems in electron physics in the area of quantum entanglement. I was waiting to see if anyone else would respond to this proper scientific topic (hooray!) raised by a keen new member of the group. So far not, so here are some comments from my purely amateur perspective.

 I have always had doubts about string theory, since I first read about it. Hard to say why, just a feeling that it is way too complicated and hard to understand for a 'theory of everything'. My hobby in this area of fundamental physics is to pick up an idea, to read a bit, to apply some common sense principles and see if I like the new idea or not. String theory failed the test!  More recently proper scientists such as Lee Smolin have come out with specific doubts and criticisms of the theory (which of course is the idea that everything in the universe is made of tiny vibrating strings of energy). So I'm glad to enjoy the observer bias that an eminent scientist agrees with me! 

 I think you have pointed to a genuinely interesting item, a hint maybe that string theory is on the right track if it can explain electron entanglement and even aid computation. But I will remain sceptical for now. I am not sure that string theory explains the fundamental mysteries of quantum mechanics, such as state superposition. None of the interpretations of QM is called 'string theory'. Instead string theory builds on space-time and, I think, QM as well,  incorporating gravity by avoiding the paradoxical picture of point particles that we get from the most developed standard formulation of QM.

The idea I spotted in the article is that entangled electrons are observed by us as the 4d perspective of a more holistic object or wave function in higher dimensional space-time. Sounds good! And string theory helps with the sums because that theory does already assume that we live in a universe with extra hidden dimensions and a lot of the maths has been worked out. 

Yes, superposition may be explained by extra dimensions. You could say that the Earth is in a state of superposition without this having anything to do with QM. The superposed state is called an orbit around the sun and is explained by the time dimension. Take a slice of time and the superposed orbit state 'collapses' into the state of being in one particular observed state of orbital position. That may be something like what's going on in the physics of QM as well. That is indeed the sort of picture being described by the maths of quantum states.  But QM is more complicated because there are different sorts of observable states such as spin, charge and so on. Do we then need lots of extra dimensions to cater for superposition between other kinds of states as well?  Yes indeed, the full mathematical picture of QM does involve a space with unlimited numbers of dimensions, the so-called Hilbert space. But I don't think anyone is seriously suggesting that Hilbert space is the 'real' underlying physical picture, it's just a mathematical description of something that we don't yet truly understand.

The string theory community are desperate to see some actual physical evidence that their huge efforts will be rewarded and will not be a waste of their time, indeed their working lives. The LHC at CERN might uncover something relevant. Meanwhile, this slim piece of evidence looks a bit like clutching at straws. What do you (or anyone else) think?
A former member
Post #: 70
I have no idea how string theory originated, but I assume it began with the premise that fundamental particles might be manifestations of tiny ‘strings’ vibrating at different frequencies. Given that there are certain properties known about ‘particles’, the frequency is adjusted to give those properties. In other words, it started with an ad hoc physical description and the mathematical values were adjusted to give results matching the observed data. If that is a fair account then it is no surprise that string theory has some applications in other fields.

The difficulty I have with string theory (apart from doing the sums) is that I don’t know how it is supposed to work. As far as I can tell the claim is that some particles, being almost as old as the universe, have been ‘vibrating’ for the best part of 14 billion years. The big bang was a big twang, but I don’t understand what string theorists think is keeping the vibration going. As far as I can tell the only plausible mechanism is the continuing expansion of the universe, the ‘physical’ stuff it is made of. I happen to think that if the universe began very small and is now very big, it has an extraordinary capacity for expansion (well, duh!) If it began as a single expanding field, then when it was the size of a marble any point in it had an extraordinary capacity for expansion, same when it was the size of a planet or a galaxy and there’s no reason to stop there; so today, any point in the universe has an extraordinary capacity for expansion. Since ‘particles’ are made of this stuff they have an extraordinary capacity for expansion; but as they are is some way ‘bound’, I can well imagine them wriggling.

Since, to my mind, ‘particles’ are ‘fountains of universe stuff’ (needs work), be they point like or string like, the fact that any number can produce a ‘sea’ of universe stuff that has the appearance of a single entity seems entirely reasonable. And if some of the maths of string theory works in this case, that’s splendid.
A former member
Post #: 186
I reckon that synopsis covers the basics. In particular the concept that every minuscule bit of stuff at the quantum level has the innate capacity to blow up very rarely to something huge is consistent with how some cosmologists have tried to unite quantum theory with cosmology. In brief: the Big Bang was born from a quantum fluctuation in a pure vacuum, other universes exist elsewhere for the same reason, there must be countless zillions of other universes, they probably differ in their physics owing to random variation in the physical constants of Nature, we live in the one universe that luckily has the right physics for our sun,  planet, chemistry and biology. Voila: everything simply explained by that one idea. 

String theory comes to the same conclusion via a different motivation: the discovery that there are indeed zillions of different possible universes described by different versions of string theory. So, to justify their abstract maths as something to do with the real world, which so far they have failed to do, they postulate that all these hypothetical universes actually exist, riding on the back of the cosmologists. That idea has been called the string theory landscape. Every point on the map represents a whole universe. 

Personally I don't buy this idea. Far too many universes, all invisible to us and to any future technology. What's wrong with just one universe, recycling over aons and  varying Nature's physical constants as it does so, in order to provide the anthropological explanation of our own existence? Much simpler, so it passes the test for me. I once asked Roger Penrose (advocate of a recycling universe) about that and he agreed that the additional idea of the varying physics with the anthropological explanation was viable. I also asked Leonard Susskind the same question via email after hearing him at a talk (he is a strong advocate of the string landscape idea) and he did not reply. Draw your own conclusions!
lan B.
user 10895495
London, GB
Post #: 289

Yes, a good summing up by Andrew in the foregoing posting. String theory remains for the moment intriguing, but so far little else apart from, possibly, unintended applications in unexpected fields. (Which, when you come to think about it, surely qualifiers it, if snything, as part of maths, rather thn physics, as Ian Roxburgh, head of the Astronomy Department at QMUL, occasionally used to ruefully point out!)

I too distrust lack of parsimony.

Will, clearly the universe is expanding -- and, apparently, accelerating -- but the most parsimonious -- and least logically question-begging -- assumption is that it always has been infinite, and expanding. The only net change over time apart from its increase in entropy and the wavelengths of emitted radiations is the fact that its density has always been decreasing with the passage of time.

Otherwise, if it actually began finite, you end up with yet another, arbitrary, fundamental physical constant, don't you? To wit, the "radius" of the cosmos at time T(0) (!!!)


A former member
Post #: 71
Andrew: “I reckon that synopsis covers the basics. In particular the concept that every minuscule bit of stuff at the quantum level has the innate capacity to blow up very rarely to something huge is consistent with how some cosmologists have tried to unite quantum theory with cosmology.”

As it happens, I think ‘every miniscule bit of stuff’ is blowing up all the time. I think there are two ways to interpret ‘the expansion of the universe’; one being the apparent rushing away from each other of all the galaxies, the other that the stuff the universe is made of is spreading. That stuff is what makes ‘particles’; there isn’t anything else they could be made of.

If we accept that the universe has ‘grown’ in size from something very small to something very big then I can imagine that the colossal ‘pressure’ in the early stages caused ‘turbulence’ in a growing sea of universe stuff. Some of the vortices became tangled up with others and that is what ‘particles’ are; basically knots of vortices. Only some such knots are stable, coincidentally the same ones that make up the standard model, wouldn’t you know? When you smash them in accelerators the debris, mostly individual vortices, spin off on curved paths and in most cases unravel, ceasing to exist as ‘particles’. The ‘fact’ that the stuff they are made of is still expanding/spreading is what gives particles their enormous ‘energy’ and why so much stuff can be created by collisions, including, silly me, things that might look very like a Higgs boson.

Ian: "I too distrust lack of parsimony.

Will, clearly the universe is expanding -- and, apparently, accelerating -- but the most parsimonious -- and least logically question-begging -- assumption is that it always has been infinite, and expanding."

Well, my version reduces to: There was nothing, then there wasn’t and it grew. The end. But in one sense you could be right, it’s yer basic Zeno of Elea. If something is ‘infinite’ then our sense of scale is irrelevant. If we could observe the universe from outside (ho hum) we might conclude that it is growing, but from the inside there is the same amount of infinitely divisible ‘stuff’, the density of which has always been decreasing. Hence a particle travelling from one side to the other takes as long whether the universe is a millimetre or fourteen billion light years across from a god’s eye view. Since size is how long light takes to get from one point to another, size doesn't matter. From such a perspective something which is ‘infinitely small’ will take infinitely long to achieve any appreciable size to a god, but they can wait, they’re immortal after all.

The accelerating expansion of the universe is in the sense of the galaxies moving apart, I think they are being driven apart by the expansion of the universe stuff, dark energy if you will.
lan B.
user 10895495
London, GB
Post #: 290


Thanks Will. Hope that a felicitous Xmas/New Year was experienced by all and .. er .. I fully realise that almost certainly no-one has done, but it's customary to .. you know .. say the right thing (as the entropy continues inexorably to increase and so on) .. er ..

So: Not sure why you put quotes -- scary or otherwise -- around "energy". Unlike the notion of "particle" it is a venerable and well-verified piece of physics. (As long as we stick faithfully to its dimensional formulation and rigidly eschew any recently acquired psychoanalytical or New Agey connotations, all of which it should go without saying are absolute bollocks.)

Yes, you say that "size doesn't matter" and of course Sir Roger Penrose's identification of the state of maximum-entropy dispersion of the "precursor cosmos" with the Big Bang conditions of its immediate successor is entirely consistent with what you say. I kind of like Sir Roger's proposal, without definitely committing myself to it in the absence of current identification of concentric rings of gravitational waves stemming from supermassive black hole mergers which happened within the precursor cosmos. Another way of representing a spatially infinite universe within a finite compass is of course Poincaré's dinner-plate cosmos, in which radial distances from the centre of the "plate" emulate convergence toward an infinite limit by treating each successive distance-increment as greater than the first-defined unit distance.

Re your dark energy posit, yes, I tend to agree with that, given the current evidence. Interestingly, an always-infinite-right-from-the-beginning­ cosmos is in a sense always "self-rescaling", such that, satisfyingly, energy is always conserved globally! Thus, although the mutually distancing acceleration of each nominal point-mass (= "clusters of galaxies" given the present (small) value of around 69 km s^1 Mpc^1) clearly requires the continuous application of forces and therefore clearly also requires the input of energy to the system, if we continue to normalise the resulting distance-increments to our (arbitrarily chosen) starting values, we find that such force-generating energy is paid for by the loss of mass of each of the receding components. (Of course, viewed alternatively, these mass-points don't "shrink", but instead what is observed is simply the continually increasing distance between them. Normalisation to a constant distance-value of "1" mandates that each marker must shrink, asymptotically converging on zero size/(mass) at time t = ∞.


A former member
Post #: 72
Happy New Year everybody.

"So: Not sure why you put quotes -- scary or otherwise -- around "energy". Unlike the notion of "particle" it is a venerable and well-verified piece of physics. (As long as we stick faithfully to its dimensional formulation ....)"

The thing is, if you stick to the dimensional formulation, all you have is an “essential, entirely general explanatory theoretical abstraction”. As Feynman said:"It is important to realize that in physics today, we have no knowledge what energy is. We do not have a picture that energy comes in little blobs of a definite amount."
In everyday terms, energy is just what one thing does to another, or could do; it is not a thing in itself.

"Yes, you say that "size doesn't matter" and of course Sir Roger Penrose's identification of the state of maximum-entropy dispersion of the "precursor cosmos" with the Big Bang conditions of its immediate successor is entirely consistent with what you say.

Entropy isn’t a thing either, it is the condition things are in, the more ground into dust, the longer the wavelength, the greater the entropy. Anyway; I think what you are saying is that the completely smooth state of things before the big bang is the same thing as the state immediately after the big bang. It seems an odd claim, but insofar as things being ground down to having no size and wavelengths being stretched flat is the same as nothing existing, I suppose I agree.

I kind of like Sir Roger's proposal, without definitely committing myself to it in the absence of current identification of concentric rings of gravitational waves stemming from supermassive black hole mergers which happened within the precursor cosmos.

Why would gravitational waves survive the big bang?

Another way of representing a spatially infinite universe within a finite compass is of course Poincaré's dinner-plate cosmos, in which radial distances from the centre of the "plate" emulate convergence toward an infinite limit by treating each successive distance-increment as greater than the first-defined unit distance.

I do wish you wouldn’t keep saying ‘of course’ about things I’ve never heard of. Now that I have heard of it, it seems to be saying that the universe tends towards infinite size by getting bigger.

Re your dark energy posit, yes, I tend to agree with that, given the current evidence. Interestingly, an always-infinite-right-from-the-beginning­ cosmos is in a sense always "self-rescaling", such that, satisfyingly, energy is always conserved globally!

It maybe that the universe began like a tightly wound spring that will eventually unwind and be flat, (heat death, boo!) In the meantime, energy, where it is the power to cause change, is the unwinding of the spring, it’s flailing about causing tangles and ripples in the body of the spring, real and virtual particles, in other words, mass. Hence the tightness of the spring can turn into mass, equally a tangle that gets untangled increases the tension in the whole spring; so whether energy is tension or tangles, there is the same amount.

Thus, although the mutually distancing acceleration of each nominal point-mass (= "clusters of galaxies" given the present (small) value of around 69 km s^1 Mpc^1) clearly requires the continuous application of forces and therefore clearly also requires the input of energy to the system, if we continue to normalise the resulting distance-increments to our (arbitrarily chosen) starting values, we find that such force-generating energy is paid for by the loss of mass of each of the receding components. (Of course, viewed alternatively, these mass-points don't "shrink", but instead what is observed is simply the continually increasing distance between them. Normalisation to a constant distance-value of "1" mandates that each marker must shrink, asymptotically converging on zero size/(mass) at time t = ∞.

Yeah. I'm not sure if the universe is more like an uncoiling spring or the magic porridge pot.

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