Schneibster Posted February 19, 2014 Posted February 19, 2014 (edited) There are two possible interpretations of entanglement, and we don't know which is correct. One interpretation is that entangled particles share hidden state information, which is revealed when either particle is measured. The same measurement on the other particle yields the complementary value (not always either the same or the opposite, but always related the same way for any given entangled pair production method- see Aspect Experiment). Another interpretation is that entangled particles truly have no values, until the first measurement of either particle, but that once the measurement is made that state is superluminally transmitted to the other particle. However, as several folks have pointed out, no information other than that state can be sent, and the state cannot be known until measured, and it is not affected by local conditions; in fact, local conditions cause the state to be lost, by decoherence. The measurement got made but the observer never saw the result, is what decoherence means. Which of the two or three major subsets of interpretations of quantum mechanics you understand the most easily generally depends upon which of these interpretations of the outcomes of Bell's Inequlity experiments, such as Aspect, you most easily accept. As a relativist I tend toward the opinion that data cannot be transferred superluminally and therefore like the first alternative, with hidden varibles. However, it's also necessary to understand that the first alternative rules out simple hidden variable theories. I am tempted to say that I think it's hidden states, not hidden variables. And I think there's a big conversation about TIQM/Wheeler-Feynman Absorber Theory and reverse causality and Everett/Many Worlds and other nontraditional interpretations that we all have to have. Personally I'm most comfortable with Consistent Histories and decoherence; it seems to me that this interpretation works well with the Fluctuation Theorem, which is also extremely important in all of this since it explains entropy and the limits of entropy. What you really want to do, Addictive Science, is go start a conversation in the Speculative section about "ansibles." Those are FTL communication devices. There are some amusing suggestions along this line, but nothing so far anyone has come up with beats relativity. It's not really possible to, you know; the shape of time dictates the speed of light limit. You can't tell if "something has happened to the entangled states". To see what state it's in you have to measure it, and then it's not entangled anymore. Precisely. I should say that I define "amusing" as "not contrary to known physics but way far away from a testable hypothesis" and "interesting" as "maybe testable in the foreseeable future but not now" and "provocative" as "probably testable soon" and "fascinating" or "captivating" or "worth watching" as "imminently testable or just tested." Edited February 18, 2014 by Schneibster 1
Implicate Order Posted February 19, 2014 Posted February 19, 2014 (edited) There are two possible interpretations of entanglement, and we don't know which is correct. Great post Scneibster. The interpretations you are referring to are from the perspective of particle interpretations. Bell's inequality and Aspect's confirmatory experiment fully reflects that quantum theory dictates that for entanglement to occur, the explanatory theory must either be counterfactually indefinite or non-local in nature. When dealing with those theories that talk in terms of entangled particles, we are dealing with issues of non-locallity. Any theory that posits that the fundamental nature of that theory is particulate in nature therefore must account for non-local interactions. All hidden variables theories that are 'local' in nature fail in this test. Those hidden variable theories that allow for non-locality such as Bohm's hidden variable theory can still survive this crucial test. However if you drop the notion of particles and assume that they are mere classical representations of an underlying wavefunction that describe the state of a particle (counterfactually indefinite) then entanglement gets much easier to understand. When you deal with theories that are fundamentally counterfactually indefinite such as theories that drop the notions of particles and simply deal with superpositions of states described as wavefunctions, then entanglement ceases to be an issue. Superpositions of classical eigenstates are simply described in the wavefunction and continue to be described for the life of that superposition. Upon measurement, a further 'classically contrived' superposition is superimposed on the wavefunction from a measurement to reveal how that wavefunction will classically collapse into a classical reality of 'particles in a spacetime context' A superposition commences at the quantum event and is maintained over the life of the Schrodinger wavefunction until it is interfered with by a further superposition by either decoherence or measurement. Assuming that environmental decoherence has not occurred and dealing with a carefully contrived experiment where a measurement is undertaken to collapse a wavefunction, when an observer in a particular frame of reference classically collapses the wavefunction then his/her interrogation of the entangled superimposed wavefunction is resolved. The wavefunction classically collapses from his reference frame but still exists in a superposition from the frame of reference of another observer's reference frame that may be widely seperated and causally disconnected. What is the determining factor in relation to what both observers record is the speed with which information can be sent between both parties to reveal the measurements from both their reference frames. The entangled connection however has been in existence from the commencement of the quantum event. The delayed choice experiment of Wheeler hammers home this principle. The classical particle resolution of the 'which way' path can be resolved 'now' from wavefunction collapse relating to a superposition that has been in occurrence since 13 or so billion years ago. The fact is that the superposition of states has been in existence since this quantum event (and still remains in existence for other observers who are yet to perform their measurements) and the wavefunction collapse relates to the entire collapse of the wavefunction that describes the information state of the entire causal lightcone of the particular frame of reference used in the experiment to determine the which way path. If you superimpose causal lightcones of different classical observers that are causally connected, a shared classical reality can be described where all observers agree on the sequence of events described by that information path. Fortunately the invariable c for all observers allows a synchronisation of information paths to provide an objective reality out there that we all can agree with. Edited February 19, 2014 by Implicate Order 1
Schneibster Posted February 19, 2014 Posted February 19, 2014 (edited) I'm gonna like this site. Nice post, Implicate Order. My immediate reaction is to say "Bell's Theorem implies that either locality, or local realism, is wrong, and the other is right." "Locality" means that state cannot be sent faster than light; "local realism" means that Heisenberg uncertain quantities have real values even though we can't measure them. So either we violate the "locality" postulate of Special Relativity, by sending state data instantaneously with the collapse of the wave function (and BTW also trash the relativity of simultaneity), or else we claim that Heisenberg uncertain quantities have no value, in a manner that is not consistent with local reality as we experience it, very similar to the old George Carlin joke, "And now for tomorrow's weather: tomorrow there will be no weather. (Pauses for laughs.)" This delineates the limits of what we can know. Edited February 19, 2014 by Schneibster 2
Implicate Order Posted February 20, 2014 Posted February 20, 2014 (edited) My immediate reaction is to say "Bell's Theorem implies that either locality, or local realism, is wrong, and the other is right." I like you am a relativist. I say dispatch local realism to the sin bin. What science has consistently demonstrated is that what once was regarded as 'invariant' inevitably turns out to be 'co-variant' in nature thanks to symmetry. As Emmy Noether concluded, spacetime symmetries lead to Conservation Laws. The fewer symmetries involved leads to fewer Conservation Laws. You need to peel the onion skin again and again to seach for any possible fundamental invariants. At the bottom of the classical ladder is 'c', the Planck scale quantised definition of spacetime and an ordered high entropy state to get the classical ball rolling. All other classical 'things' such as temperature, pressure, seperate space or seperate time, forces, spacetime curvature, particles/fields etc. have dissolved away as 'classical illusions' at this stage. I think we can go further in our extension of relativism than what has been achieved by GR and QM which to me represent alternate expressions (co-variant expressions) of a 'classical reality'. QM in this context is the classical expression of quantum phenomena that arises from the planck boundary. At a more fundamental level itself is the quantum domain itself which can only be described through abstract mathematics (hilbert spaces). The problem with theoretical constructions from the bottom up is that we need to comence with an infinite array of classical commencement states for our construction (reflected by the singularity). The infinite array leaves us uncertain which approach is the valid approach that describes our classical universe. I think we need to flip the way we construct a theory to a top down approach and at least recognise we need to start with the here and now (what is classically observed) and then construct our theories backwards to their initial commencement state. I think these constructions need to be information theoretic in nature in that we need to describe all the possible states that can be 'classically described' by different observers and then work backwards following causal routes backwards that commence from that 'now state' to ultimately describe the 'first cause' fundamental information unit/s from that particular frame of reference. Once we have achieved that, we then superimpose the causal histories from each possible classical frame of reference to explain the classical singularity and the uncertainty associated with the initial classical commencement point. Edited February 20, 2014 by Implicate Order
Schneibster Posted February 20, 2014 Posted February 20, 2014 You are stimulating long unused neurons. I'll see what I can do this evening; I'm helping my wife deal with upper jaw fillings so maybe not 'til tomorrow, but don't worry about me losing interest! We're getting out of astronomy/cosmology and into, IMHO, "Modern Physics." And I am totally stoked to have that conversation; if you haven't fired it up over on that forum by tomorrow I will. You've opened Noether's Theorem. This is just another look into the underlying symmetries; now you've got forces, symmetries, mathematical theorems, and conservation laws and fundamental invariances not only of the spacetime dimensions but of the dimensions in the Calabi-Yau geometry that defines our universe, which we will eventually establish the precise parameters of by physical measurement. And all of these things are tangled together in one single definition of the geometry of our universe. There are many other universes around us. They're no more than hundreds of billions of light years away. I read an article that claimed that the most probable distance to a universe containing another Schneibster almost just like me, writing almost exactly this message to you at almost exactly this time, is around 200 billion light years. Let me suggest something: how about the Anthropic Principle? String Theory says there are 10300 possible dimensional arrangements/Calabi-Yau spaces. Eternal inflation suggests that all of them get tried over time, over and over again. We look at the universe around us and it looks like a huge bunch of empty voids surrounded with a scum, or "web," or whatnot, of matter, of which our Local Group of Galaxies appears to be a microscopic crumb within a cluster of galaxies within a supercluster of galaxies within a thread of this scum web surrounding the huge voids of universes that collapsed nearby and left signatures in our CMBR. Most universes just collapse back into themselves and leave voids. These voids coexist with the scum web of matter that's left over from the original inflation on both sides of us. One side is the Sloan SDSS Her-CrB Great Wall, and the other is the recently discovered 10Gly square wall defined by GRBs. These events are what squeezed the matter that surrounds us tightly enough to form galaxies. Well I did better than I thought. 1
Implicate Order Posted February 20, 2014 Posted February 20, 2014 (edited) I have dabbled with the multi-verse but a real shakeabout in my thoughts occurred only recently with research by Fotini Markopoulou in regards to Causal Dynamical Triangulations. In a nutshell it refers to a background independent quantum gravity approach where rather than talking in terms of multi-verses talks in terms of multiple reference frames in a classical 3D and 1T universe. The approach recognises that to put General Relativity and Quantum mechanics on the same footing to be able to unite the two frameworks we need to ensure the frames of references applied to both theories are similarily on the same footing. Namely when both theories are applied to the frame of reference of an observer embedded in the system. CFD assumes like GR that the definition of the universe is 'all that exists'. In that context it is impossible to have a frame of reference interpreting this universe from the outside. Interpretations must be done from within the universe. General relativity has always been a theory examining the universe as a system from the inside. By superimposing the different frames of reference applicable to different frames of reference we then develop a 'block universe' description of the classical reality. Quantum Mechanics until CFD however always assessed a system from the frame of reference of an observer located outside the system. To be equivalent to GR, the frame of reference of the quantum observer needs to be embedded in the system they are interrogating. This makes sense to me. CFD therefore inserts causal light cones onto the quantum lattice grid of spacetime and defines wavefunctions by the content of information contained within each light cone. Given this new approach both theories then are assessed therefore from the frame of reference of any observer located at any point in spacetime or in any state of relative motion and their associated scope of the system (the laboratory within which they conduct experiments) is defined by the light cone (or hubble volume) surrounding the observer. Provided the light cones are all causally connected then the same physics should be applicable in each light cone from both a QM and GR perspective. This approach can then use gauge symmetries to then determine how different points of view can see frame dependent attributes of 'classicalism' emerge such as spacetime, forces, particles, boundaries etc. emerge with the classical universe. The result is a multi-frame of reference viewpoint in 3D and 1T as opposed to a traditional quantum multi-verse occupying seperate universes. By superimposing the different wavefunctions associated with the information contained in each observers light cone, you can then see how a 'shared classical universe arises' where every frame of reference that shares a portion of causality with each other will agree on the classical reality that emerges. This approach is giving me so much joy as it is insisting that before we entertain the possibilities of a multi-verse, it's first best to check whether or not our classical reality which can actually be observed and verified can be understood through a theory operating within the 3D and 1T context. It appears to me that CFD and also the Holographic principle from the string theory camp are getting extremely close to a 'Theory of the Classical Universe'. After that, then we can entertain the notion of wondering whether other universes may or may not be described. Edited February 20, 2014 by Implicate Order
Schneibster Posted February 20, 2014 Posted February 20, 2014 (edited) I guess I'm pretty good with quantum theory undergoing transition to classical theory as described by the Fluctuation Theorem. Are you familiar with that? This is maybe not the place. "Modern Physics" seems more likely for a conversation about the transition from classical to quantum theories. Edited February 20, 2014 by Schneibster
imatfaal Posted February 21, 2014 Posted February 21, 2014 I guess I'm pretty good with quantum theory undergoing transition to classical theory as described by the Fluctuation Theorem. Are you familiar with that? This is maybe not the place. "Modern Physics" seems more likely for a conversation about the transition from classical to quantum theories. I had the Fluctuation theorem pegged as a statistical mechanics idea that allows (ie quantifies the exact probability that) both quantum and classical systems can seem show a potential decrease in entropy contra the second law - not as an attempt for a unification of qm and gr
Schneibster Posted February 21, 2014 Posted February 21, 2014 I had the Fluctuation theorem pegged as a statistical mechanics idea that allows (ie quantifies the exact probability that) both quantum and classical systems can seem show a potential decrease in entropy contra the second law - not as an attempt for a unification of qm and gr Yes. It defines the line between "classical" and "quantum." It's the new version of the 2LOT; it defines the size, mass, and time above which things are classical and below which they are quantum. I never said anything about unification. QM degenerates to CM in the size limit. Always has. The FT defines the size limit.
imatfaal Posted February 21, 2014 Posted February 21, 2014 Yes. It defines the line between "classical" and "quantum." It's the new version of the 2LOT; it defines the size, mass, and time above which things are classical and below which they are quantum. I never said anything about unification. QM degenerates to CM in the size limit. Always has. The FT defines the size limit. Do you have any reference for your interpretation of the Fluctuation theorem - as that does not tally with my thoughts of it; but admittedly I have only a passing acquaintance. My reading is that Fluctuation theorem applies to both quantum systems and classical (the second law really only applies to macroscopic) and does not distinguish nor delineate. It allows the time-reversible equations (which exist in both classical and quantum systems) to be held to apply where the second law seems to imply that they could not. "quantum theory undergoing transition to classical theory" this implies a unification - it does not imply the fact that macroscopic objects are too difficult to do the maths for qm. I am also not sure about the use of "degenerate" - it is that we stop using one set and start using another. As examples of the difference I am trying to highlight GR simplifies to SR in the limit of flat space ie with no gravity, SR in the limit of slow speed is the same as newtonian mechanics. QM does not do this to GR - this is the important transition of quantum to classical.
Schneibster Posted February 21, 2014 Posted February 21, 2014 (edited) Do you have any reference for your interpretation of the Fluctuation theorem - as that does not tally with my thoughts of it; but admittedly I have only a passing acquaintance. My reading is that Fluctuation theorem applies to both quantum systems and classical (the second law really only applies to macroscopic) and does not distinguish nor delineate. It allows the time-reversible equations (which exist in both classical and quantum systems) to be held to apply where the second law seems to imply that they could not. 2LOT no longer strictly applies below size xyz, mass m, and timespan t1 - t0. Two important facts: 1. The FT is not a physics theory. It is a mathematics theorem. It has an absolute mathematical proof. You should have a look at its postulates. 2. QM does not deal with Maxwell-Boltzmann statistics; MB statistics do not have spin. QM uses Fermi-Dirac statistics for fermions, that is, half-spin particles, that is, matter, and Bose-Einstein statistics for bosons, that is, unit-spin particles, that is, force/energy. There are no "maxwellions" or "boltzmannions." The closest is Cooper pairs, which are bosons. You should be able to find out what you need to know about the FT from the Wikipedia article. It's pretty good. I've been there a lot and compared it with quite a few different articles elsewhere (like hyperphysics) and it looks like it's one of the good ones. Edited February 21, 2014 by Schneibster
Implicate Order Posted February 22, 2014 Posted February 22, 2014 I guess I'm pretty good with quantum theory undergoing transition to classical theory as described by the Fluctuation Theorem. Are you familiar with that? This is maybe not the place. "Modern Physics" seems more likely for a conversation about the transition from classical to quantum theories. Looks like I have a bit of reading to do on the 'Fluctuation Theorem'. Thanks for the heads-up. It sounds interesting. So many different system approaches arriving at similar conclusions. It is quite exciting.
Schneibster Posted February 22, 2014 Posted February 22, 2014 (edited) Reality be's, IO. Remember: Camus: To be is to do. Freud: To do is to be. Ol' Blue Eyes: Do-be do-be do. And more seriously: pay serious attention to my post directing you toward the postulates of the FT. The Wikipedia article is particularly rich in this area. Edited February 22, 2014 by Schneibster
Implicate Order Posted February 22, 2014 Posted February 22, 2014 And more seriously: pay serious attention to my post directing you toward the postulates of the FT. The Wikipedia article is particularly rich in this area. Ta Schneibster.
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