Copenhagen Interpretation
This group tends to relate concepts back to MWI. Perhaps CI is a useful way to think as well... At a given point in time, a thinking entity is only aware of a small subset of its surroundings. This suggests an ensemble of all mathematical possibilities that are consistent with that mind in that current state of awareness. This sounds like CI which uses the concept of superposition of states *before* an experiment is performed. - David --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.797 / Virus Database: 541 - Release Date: 11/15/2004
Re: Copenhagen interpretation Beables (to be or not to be?)
Title: Re: Copenhagen interpretation Beables (to be or not to At 18:40 +0100 19/07/2002, Gordon ([EMAIL PROTECTED]) wrote: Everett was not center around mind either ask David about (I believe) his 1977 conversation with Everett in which he said his theory was Manyworlds and NOT many minds! Yes but remember the remark he made about the mouse being multiplied, not the universe, at least not at once, but only at the speed of decoherence (in modern talk). My own interpretation of QM is better described by Many-Worlds. In particular I don't appreciate Albert-Loewer many-minds because they are obliged to postulate the probabilities. Now David Deutsch use the comp hypothesis explicitly, and, unless I have been wrong comp entails that the laws of physics originates from what the consistent (immaterial) machines/programs/relative-numbers are able to anticipate correctly. There is no magic there, just Theoretical Artificial Intelligence + some amount of arithmetical platonism. (Very well defended by David also). Mind object are just object like the game of Bridge, numbers, programs, software, and plausibly quarks and gluons too ... I would say every sentences in FOR is compatible with comp, but most of them are deducible from a deeper theory which is just number theory + inside views captured by the logic of incompleteness phenomena and variants. The main point is that with comp I don't see how such a move is avoidable. I will try to write a longer and clearer English paper. I insist I am not a defender of the comp hypothesis. I am just telling to those who believes in the comp hyp, that the mind body problem is, for them, twice as much difficult than usually thought. This because with comp you need not only to solve the qualia/consciousness problem but also the problem of the origin of empirical laws. This is not obvious! Then I show also that comp + modern math gives non trivial hints for both part. Beside I thought you said your theory had nothing to do with QM,sounds alot like you are trying to give a interpretation to it to me? I just show that with the comp hyp Physics need to redefined as the study of a---hard to make precise (it's part of the MP problem)---measure on all computations. In fact with comp we will redo all physical discoveries in the reverse direction. Comp gives first a machine psychology then many histories interpretation, then it should gives gravitations, then weak force, then eventually electro-magnetism ... (perhaps in ten centuries). From the comp view the classical Poisson part of physics will be the hardest part to derive., and then geometry ... (I speculate a little bit here but it is to give an idea). Of course we can dig on the two sides: machine psychology (eternal self reference logic and variants) and human evolving physics; why not? Hoping you are not too much confused, (I am also confused!, but it is too early to pretend comp refuted, and with comp the psycho/physico reversal is not an idea: it is a theorem(*)). Regards, Bruno (*) if someone find a flaw or even imprecisions I would be grateful letting me know it. (links http://www.escribe.com/science/theory/m3044.html ) -- http://iridia.ulb.ac.be/~marchal/
Re: Copenhagen interpretation
MWI is a fully deterministic theory, but it is not the only deterministic theory consistent with QM. I believe that 't Hooft's theory is more natural from the point of view that universes are programs. It is hard for me to understand how you get interference between ``nearby´´ universes or programs. According to 't Hooft QM would arise in a ``single universe´´ References: [1] Quantum Gravity as a Dissipative Deterministic System http://arxiv.org/abs/gr-qc/9903084 [2] Determinism in Free Bosons http://arxiv.org/abs/hep-th/0104080 [3] How Does God Play Dice? (Pre-)Determinism at the Planck Scale http://arxiv.org/abs/hep-th/0104219 [4] Quantum Mechanics and Determinism http://arxiv.org/abs/hep-th/0105105 - Oorspronkelijk bericht - Van: Bruno Marchal [EMAIL PROTECTED] Aan: [EMAIL PROTECTED] Verzonden: vrijdag 12 juli 2002 17:30 Onderwerp: Copenhagen interpretation Saibal wrote: This all assumes that photons, electrons, etc. are real. We don't know that. If you were Einstein, and you were faced with Bell's result, you could have concluded that the nonexistence of local hidden variables implies that elementary paricles don't exist. They are mere mathematical tools to compute the outcome of experiments. The real underlying theory of Nature could be still be deterministic. Recently 't Hooft has shown how QM can emerge out of a deterministic theory. In this case QM has to be interpreted according to the Copenhagen interpretation. But QM-without-collapse *is* a fully deterministic theory. In QM-without-collapse the indeterminism is a first person indeterminism quite comparable to what appears in classical self-duplication process (if I may repeat myself). It seems to me that 't Hooft theory is very speculative, but then I am not sure I fully understand it, for sure. Bruno Yahoo! Groups Sponsor -~-- Save on REALTOR Fees http://us.click.yahoo.com/Xw80LD/h1ZEAA/Ey.GAA/pyIolB/TM -~- Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Re: Copenhagen interpretation
Gordon wrote: Saibal Mitra wrote: This all assumes that photons, electrons, etc. are real. We don't know that. If you were Einstein, and you were faced with Bell's result, you could have concluded that the nonexistence of local hidden variables implies that elementary paricles don't exist. [Gordon] I dont know how you come to that? Very simply, if Nature is described by a single universe local classical deterministic theory and if local hidden variables are excluded experimentally, the only way out is that the objects to which the hidden variables are supposed to be associated with, don't exist. [Saibal] They are mere mathematical tools to compute the outcome of experiments. The real underlying theory of Nature could be still be deterministic. Recently 't Hooft has shown how QM can emerge out of a deterministic theory. In this case QM has to be interpreted according to the Copenhagen interpretation. [Gordon] Why, if anything it would be closer to Bohm(1952 Mech version) or MWI(1957 version) than saying than CI,In fact HV say that they is something beneath lower sub levels where CI dont,or aleast can explain them ! Funny thing is that 't Hooft and some other who first laught about Ontological theory are now look at them for answers, however the one they found are too simple and may have more problem when takening it onto a broader view? I would prefer to look further into Bohm/Hiley or Deutsch/Dewitt area myself! I never studied Bohm theory in any detail. From what I know it makes the same predictions for experimental outcomes as ordinary quantum mechanics. According to 't Hooft's theory QM would have to break down at the planck scale. Also, there would be a limit on the performance of quantum computers. Saibal
Copenhagen interpretation
This all assumes that photons, electrons, etc. are real. We don't know that. If you were Einstein, and you were faced with Bell's result, you could have concluded that the nonexistence of local hidden variables implies that elementary paricles don't exist. They are mere mathematical tools to compute the outcome of experiments. The real underlying theory of Nature could be still be deterministic. Recently 't Hooft has shown how QM can emerge out of a deterministic theory. In this case QM has to be interpreted according to the Copenhagen interpretation. - Oorspronkelijk bericht - Van: Bruno Marchal [EMAIL PROTECTED] Aan: scerir [EMAIL PROTECTED] CC: [EMAIL PROTECTED] Verzonden: vrijdag 12 juli 2002 12:44 Onderwerp: Re: Morality in a Block Multiverse Hi Serafino, At 23:00 +0200 10/07/2002, scerir wrote: Hal You can also have a block universe in QM with the many-world interpretation. It has a more complicated geometric structure but philosophically it is deterministic, with the same issues regarding changes, free will, etc. I'm not an Everettista, anyway let us try. Alice has photon 1, which is in a certain quantum state, unknown to Alice and unknown to anyone else. Let us say that this unknown quantum state is |psi_1 = a |0_1 + b |1_1 with |a|^2 + |b|^2 = 1 and where |0_1 and b |1_1 represent two orthogonal quantum states and a and b represent complex amplitudes. Now Alice wants to transfer (I say: transfer) her quantum state to Bob, which is remote, so she can not directly deliver it to him. But, fortunately, Alice also has a pair of entangled photons, let us say the photon 2 and the photon 3, and she already gave the photon 3 to Bob, who still has this particle. Leaving apart normalization factors we can write that the total state of those 3 photons is |psi_1,2,3 = ( |0_1 |1_2 - |1_1 |0_2 )(- a |0_3 - b |1_3 ) + ( |0_1 |1_2 + |1_1 |0_2 ) (- a |0_3 + b |1_3 ) + ( |0_1 |0_2 - |1_1 |1_2 )( a |1_3 + b |0_3 ) + ( |0_1 |0_2 + |1_1 |1_2 ) ( a |1_3 - b |0_3 ) Alice now performs a measurement on photons 1 and 2 and she projects her two photons onto one of these four states below: ( |0_1 |1_2 - |1_1 |0_2 ) ( |0_1 |1_2 + |1_1 |0_2 ) ( |0_1 |0_2 - |1_1 |1_2 ) ( |0_1 |0_2 + |1_1 |1_2 ) And consequently Bob will found his photon in one of these four states below (- a |0_3 - b |1_3 ) (- a |0_3 + b |1_3 ) ( a |1_3 + b |0_3 ) ( a |1_3 - b |0_3 ) Now Alice, who wants to transfer the unknown quantum state of photon 1 to Bob, must inform Bob, via a classical channel, about her measurement (projection) result (on photons 1 and 2). So Bob can perform (25% of times it is not required) the right simple unitary transformation on his photon 3, in order to obtain the initial quantum state |psi_1 = a |0_1 + b |1_1 Note that Alice does not get any information, from her measurement, about the quantum state she wants to transfer and about the values of those a and b amplitudes. Note also that during Alice's measurement photon 1 loses his original quantum state, as required by the no-cloning theorem. Ok, that was the basic teleportation (= trasportation) of a quantum state from Alice to Bob. Now something strange happens in the MWI version. Alice's measurement does not project the superposition of ( |0_1 |1_2 - |1_1 |0_2 ) ( |0_1 |1_2 + |1_1 |0_2 ) ( |0_1 |0_2 - |1_1 |1_2 ) ( |0_1 |0_2 + |1_1 |1_2 ) onto just one of these quantum states (above). They all exist. And all these quantum states (below) also exist (- a |0_3 - b |1_3 ) (- a |0_3 + b |1_3 ) ( a |1_3 + b |0_3 ) ( a |1_3 - b |0_3 ) and one of them (1 over 4 = 25% of times) is the same quantum state that Alice wanted to transfer to Bob. Thus it seems that in the MWI of teleportation the quantun state it is not teleported or trasported but it is already there, and it is already there, in one of those branches, from the beginning. This stuff reminds me of the block universe, at least a bit. s. [still not an Everettista] :-) Still not? Even after this nice presentation of (quantum) teleportation in the MW view? Your last remark confirms my feeling that quantum information is just classical information about which partition of the multiverse we belong (and measurement is always sort of self-localisation). Do you know the paper by Peres http://xxx.lanl.gov/abs/quant-ph/9904042 Peres shows how to teleport entanglement in the past! In the MW view there is no problem at all, neither non-locality, nor 3-indeterminacy. But Peres concludes its paper by insisting on keeping the Copenhague view. It's quite mysterious. If you have time to look at it I would appreciate your opinion. Bruno
Re: Copenhagen interpretation
Saibal Mitra This all assumes that photons, electrons, etc. are real. We don't know that. If you were Einstein, and you were faced with Bell's result, you could have concluded that the nonexistence of local hidden variables implies that elementary paricles don't exist. They are mere mathematical tools to compute the outcome of experiments. The real underlying theory of Nature could be still be deterministic. Recently 't Hooft has shown how QM can emerge out of a deterministic theory. In this case QM has to be interpreted according to the Copenhagen interpretation. Nice question. Einstein wrote a beautiful paper (1927) Does Schroedinger's Wave Mechanics Determine the Motion of a System Completely or Only in the Sense of Statistics? but it is still unpublished! It's an interesting hidden variables theory! References: -J.T. Cushing, Quantum Mechanics, Un. Chicago Press, 1994, pages 128-129, and 139-140, and 251. -D. Howard, Space-Time and Separability, in Potentiality, Entanglement and Passion-at-a-Distance, R.S.Cohen + M.Horne + J.Stachel (eds.), Kluwer A.P., 1997 -J. Stachel, Feynman Paths and Quantum Entanglement, in Potentiality, Entanglement and Passion-at-a-Distance, R.S.Cohen + M.Horne + J.Stachel (eds.), Kluwer A.P., 1997. Anyway I think that Einstein would say something like ... ' This statistical interpretation is now universally accepted as the best possible interpretation for quantum mechanics, even though many people are unhappy with it. People had got used to the determinism of the last century, where the present determines the future completely, and they now have to get used to a different situation in which the present only gives one information of a statistical nature about the future. A good many people find this unpleasant; Einstein has always objected to it. The way he expressed it was: 'The good God does not play with dice'. Schroedinger also did not like the statistical interpretation and tried for many years to find an interpretation involving determinism for his waves. But it was not successful as a general method. I must say that I also do not like indeterminism. I have to accept it because it is certainly the best that we can do with our present knowledge. One can always hope that there will be future developments which will lead to a drastically different theory from the present quantum mechanics and for which there may be a partial return of determinism. However, so long as one keeps to the present formalism, one has to have this ^ indeterminism. ' from P.A.M. Dirac, The Development Of Quantum Mechanics, Conferenza Tenuta il 14 Aprile 1972, Roma Accademia Nazionale dei Lincei, 1974 [page 6]
Re: Copenhagen interpretation
Thank you, Saibal Mitra. If I may add one remark to your position: to They are mere mathematical tools to compute the outcome of experiments. I would add: and the presupposition of such contributed to the design of those experiments with a presupposition of acceptable vs rejectable results. John Mikes [EMAIL PROTECTED] http://pages.prodigy.net/jamikes; - Original Message - From: Saibal Mitra [EMAIL PROTECTED] To: Bruno Marchal [EMAIL PROTECTED]; scerir [EMAIL PROTECTED] Cc: FoR [EMAIL PROTECTED]; [EMAIL PROTECTED] Sent: Friday, July 12, 2002 8:11 AM Subject: Copenhagen interpretation This all assumes that photons, electrons, etc. are real. We don't know that. If you were Einstein, and you were faced with Bell's result, you could have concluded that the nonexistence of local hidden variables implies that elementary paricles don't exist. They are mere mathematical tools to compute the outcome of experiments. The real underlying theory of Nature could be still be deterministic. Recently 't Hooft has shown how QM can emerge out of a deterministic theory. In this case QM has to be interpreted according to the Copenhagen interpretation. - Oorspronkelijk bericht - Van: Bruno Marchal [EMAIL PROTECTED] Aan: scerir [EMAIL PROTECTED] CC: [EMAIL PROTECTED] Verzonden: vrijdag 12 juli 2002 12:44 Onderwerp: Re: Morality in a Block Multiverse Hi Serafino, SNIP
