tag:blogger.com,1999:blog-3832136017893749497.post3558639823694033103..comments2023-09-29T08:49:30.765-04:00Comments on Elliptic Composability: Florin Moldoveanuhttp://www.blogger.com/profile/01087655914212705768noreply@blogger.comBlogger47125tag:blogger.com,1999:blog-3832136017893749497.post-38471114874318509762016-08-17T07:16:00.170-04:002016-08-17T07:16:00.170-04:00I think there is some relationship, maybe a dualit...I think there is some relationship, maybe a duality, between symmetries that are nonlocal and those that are local, or that define causal processes by light cone condition, time ordering etc. If so this would remove a vast number of local symmetries or amplitudes from the real physics. <br /><br />Lorentz invariance is a pretty strong bedrock. If spacetime is built up from entanglement then Lorentz invariance is a manifestation of QM in some manner. If so there is then some relationship between nonlocal and local physics. Something very subtle lies here.<br /><br />Nonlocal physics does not violate causality or locality. Nonlocality does not involve causal influences or the transmission of information along spacelike intervals. Even when there is a nonlocal correlation this can only be realized to an observer through the transmission of a classical signal. This converts an entangled state, say a state involving two spins that has no ontological meaning to those component spins, into the nonentangled state where the qubit content of the entangled state is transferred to the new form as component spins. <br /><br />I am a bit curious about what Lubos is claiming, and so far he has not illustrated how teleportation of states can occur classically. He is not always right about things. I checked his blog recently where he states that regions of Asia and Africa were maybe better off under the European empires. That is a bit of a long claim.Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-7047987370543290662016-08-16T22:38:10.397-04:002016-08-16T22:38:10.397-04:00Lawrence Crowell,
Ok!I did not see it at that time...Lawrence Crowell,<br />Ok!I did not see it at that time.But now this is becoming clearer.What are locality and non-locality, is a matter of furious debate!Many people (specially Lubos) take locality as synonymous with Lorentz invariance. I am mostly with him on that issue. e.g. our usual field theory is called local field theory.As I mentioned once before, Bell unfortunately used the word non locality for non-factorizability. I am not sure if you and/or Florin use the word 'non-locality'in the same sense or have deeper meaning in mind. It seems that both of you believe in Lorentz invariance. So I would like to understand your 'non-locality' better. Is it a matter of semantics only or not?kashyap vasavadahttps://www.blogger.com/profile/10732897306667764590noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-24812757022198090182016-08-16T20:40:58.602-04:002016-08-16T20:40:58.602-04:00This comment has been removed by the author.kashyap vasavadahttps://www.blogger.com/profile/10732897306667764590noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-5231126227089529752016-08-16T19:18:48.748-04:002016-08-16T19:18:48.748-04:00That was what I wrote about the other day. Particl...That was what I wrote about the other day. Particles 1 and 4 can be a correlated through teleportation, which does not require a direct interaction of the particles. As I said, teleportation is a case of nonlocality and it is not something in classical mechanics.Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-33339797247783632872016-08-16T16:10:15.043-04:002016-08-16T16:10:15.043-04:00Ok! I now see that this picking of 1 of 4 outcomes...Ok! I now see that this picking of 1 of 4 outcomes is what you guys are calling filtering.So the other three do not result in entanglement of 1 and 4. Now I am even more curious about Zeilinger's or someone else's set up for swapping or teleportation.I guess the devil is in details! kashyap vasavadahttps://www.blogger.com/profile/10732897306667764590noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-2544368077150782152016-08-16T16:02:44.825-04:002016-08-16T16:02:44.825-04:00This comment has been removed by the author.kashyap vasavadahttps://www.blogger.com/profile/10732897306667764590noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-81824269300617421462016-08-16T15:17:26.367-04:002016-08-16T15:17:26.367-04:00Excellent question: The past is the past and canno...Excellent question: The past is the past and cannot be changed, However one can discover correlations about events in the past. But the story is subtle. Charlie's measurement can have one of 4 outcomes. In 25% of the cases one uncovers the past correlation. The one in 4 cases is itself a random outcome. Think of Charlie result of measurement as the key to unlock the correlation which otherwise would remain hidden.Florin Moldoveanuhttps://www.blogger.com/profile/01087655914212705768noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-60083054320451961442016-08-16T15:11:45.473-04:002016-08-16T15:11:45.473-04:00Drawing is messed up, now I have to write another ...Drawing is messed up, now I have to write another post with the proper picture to explain it. <br /><br />So yes, THERE IS A COUNTEREXAMPLE!Florin Moldoveanuhttps://www.blogger.com/profile/01087655914212705768noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-58863750409221491642016-08-16T15:09:37.334-04:002016-08-16T15:09:37.334-04:00I like Pilsen beer by the way.
"Charlie'...I like Pilsen beer by the way. <br /><br />"Charlie's brain which is in the intersection of the two past light cones of events -measurements of particles 1,4, right?" <br /><br />-WRONG. At the time of measuring 2 and 3 by Charlie, his brain could be outside the intersection of the past light cone of the 1 and 4 measurements. Let me try drawing it here. Assume the lines are at 45 degrees and we are dealing with Bell pairs of photons<br /><br /> ( (<br /> ) ) <br />( (<br />A1 C B4<br /> 2 3<br />\ /\ /\<br /> \ / \ / \<br /> 1\/2 3\/4 \<br /> /\ /\<br /> / \ / \<br />/ \/ \<br /> /\<br /> /..\<br /> /....\<br /> /......\<br /><br />The dotted line is the intersection of the past light cones of the Alice and Bob measurements (A1 and B4). The measurement event by Charlie is C23 and is above the light cone intersection. After measurement by Alice and Bob the photons are stored in a cavity bouncing back and forth mirrors (or stored in a fiber optics loop) and they cannot interact anymore. Time needs to pass from the moment Charlie makes the measurement for his decision to reach the fiber loops to release or not the photons.Florin Moldoveanuhttps://www.blogger.com/profile/01087655914212705768noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-19355359784326578762016-08-16T14:38:32.957-04:002016-08-16T14:38:32.957-04:00"RE the box with Charlie in it: 1-2 and 3-4 a..."RE the box with Charlie in it: 1-2 and 3-4 are in a mixed state prior to Charlie observing them. Charlie is observing a mixture of 1 and 2 and 3 and 4. That is an interaction of 1 and 4. They are entangled only when they are in the same light cone."<br /><br />Incorrect on three counts:<br />- 1 and 4 never interacts<br />- 1 and 4 can get entangled even when they are not in the same light cone<br />- the condition for entanglement is the existence of the 2 Bell pairs + a joint measurementFlorin Moldoveanuhttps://www.blogger.com/profile/01087655914212705768noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-54331557006864606542016-08-16T07:45:26.420-04:002016-08-16T07:45:26.420-04:00There is no violation of locality in that no infor...There is no violation of locality in that no information is communicated faster than light. There is no signal communication faster than light. However, nonlocality in the QM sense can't itself be reduced to locality,Lawrence Crowellhttps://www.blogger.com/profile/12090839464038445335noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-54836624245569627372016-08-16T02:13:09.313-04:002016-08-16T02:13:09.313-04:00BTW my nation is the #1 drinker of beer and I am n...BTW my nation is the #1 drinker of beer and I am not avoiding ethanol in any systematic way but I am in no way a major drinker.<br /><br />In average, and almost regularly, I drink 0.5 liters of beer that has about 4% of ethanol in average. That's about 20 ml of ethanol a day in average. None of it was drunk in the vicinity of 1 hour around the moments when I was writing replies. This 1 hour is enough for the 20 ml of ethanol to get almost entirely out of the blood system.<br /><br />Beer is mostly healthy in normal enough amounts.Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-52310327577626491872016-08-16T02:09:05.165-04:002016-08-16T02:09:05.165-04:00Florin Moldoveanu: Put the beer down and read care...Florin Moldoveanu: Put the beer down and read carefully what I said: "Yes, filtering under appropriate conditions do produce correlations"<br /><br />Excellent. Now, the filtering is caused by the decision in Charlie's brain which is in the intersection of the two past light cones of events -measurements of particles 1,4, right? <br /><br />So you haven't found any counterexample to my statement, have you?Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-25547589596125136752016-08-15T22:35:59.692-04:002016-08-15T22:35:59.692-04:00Florin,
RE the box with Charlie in it: 1-2 and 3...Florin, <br /><br />RE the box with Charlie in it: 1-2 and 3-4 are in a mixed state prior to Charlie observing them. Charlie is observing a mixture of 1 and 2 and 3 and 4. That is an interaction of 1 and 4. They are entangled only when they are in the same light cone.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-2150230256465706922016-08-15T13:06:56.815-04:002016-08-15T13:06:56.815-04:00I forgot to mention one thing. Is this a matter of...I forgot to mention one thing. Is this a matter of delayed choice where 2 and 3 interact in future, but affect 1 and 4 which happened in past?kashyap vasavadahttps://www.blogger.com/profile/10732897306667764590noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-41717277721064572212016-08-15T11:59:50.717-04:002016-08-15T11:59:50.717-04:00There is one thing for which most physicists would...There is one thing for which most physicists would agree is Lorentz Invariance (no FTL) which is called 'locality' by many people. So let us agree on that first and then proceed further! I thought particles 2 and 3 are sent to Charlie for Bell type measurement which entangles them. I do not understand why Charlie has control over 1 and 4 which are really under control of Alice and Bob.I guess one has to understand how experiment is done. Perhaps Zeilinger(if my recollection is right), father of such experiments, can weigh on this.Is it possible to invite him to write a comment or guest blog? I am sure he will not question Lorentz invariance, but he can resolve other issues.kashyap vasavadahttps://www.blogger.com/profile/10732897306667764590noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-11038458404961361722016-08-15T11:37:27.315-04:002016-08-15T11:37:27.315-04:00Put the beer down and read carefully what I said: ...Put the beer down and read carefully what I said: "Yes, filtering under appropriate conditions do produce correlations"<br /><br />"How could you question that the filtering is the *reason* for the correlation?" I am not. Please comment when you are not drunk.Florin Moldoveanuhttps://www.blogger.com/profile/01087655914212705768noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-27444901777065909922016-08-15T11:26:46.815-04:002016-08-15T11:26:46.815-04:00Filtering doesn't produce correlations "a...Filtering doesn't produce correlations "automatically" i.e. always but it obviously creates correlations in this case - and most others.<br /><br />Charlie is simply releasing the pair when their properties are the same, and otherwise kills them. How could you question that the filtering is the *reason* for the correlation? You must be not just an obnoxious anonymous troll but a complete imbecile not to understand this.Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-72398756374297813052016-08-15T11:24:21.920-04:002016-08-15T11:24:21.920-04:00"filtering is the process that is producing m..."filtering is the process that is producing many/most correlations in the most general situations."<br /><br />BINGO: you just contradicted yourself.<br /><br />Yes, filtering under appropriate conditions do produce correlations and this contradicts your overreaching incorrect statement: "Whenever there's some correlation in the world – in our quantum world – it's a consequence of the two subsystems' interactions (or common origin) in the past.". <br /><br />This is the point of the post: interaction between particles is not ALWAYS needed to produce correlations.Florin Moldoveanuhttps://www.blogger.com/profile/01087655914212705768noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-55460587600819427112016-08-15T10:32:20.236-04:002016-08-15T10:32:20.236-04:00no , it is not obvious at all . filtering out part...no , it is not obvious at all . filtering out particles does not automatically create interaction between particles. I start to believe Lubos is masking his incompetence by vulgarity.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-76190266170340475622016-08-15T09:37:25.973-04:002016-08-15T09:37:25.973-04:00Florin:
"S1 does not imply nonlocality, but ...Florin:<br /><br />"S1 does not imply nonlocality, but nonrealism"<br /><br />It does not imply non-locality for the particle that is measured, but implies non-locality for the distant particle. You measure one particle here and you create the value of the spin for both entangled particles (including the one that is far away).<br /><br />AndreiAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-79129789903701312662016-08-15T09:23:36.737-04:002016-08-15T09:23:36.737-04:00If two particles are released by Charlie when they...If two particles are released by Charlie when they have the same property, and not released when they have the opposite property, then obviously both of these particles are being affected by the same interaction in their shared past light cone - the thinking processes in Charlie's brain.<br /><br />I have explained this trivial thing just on this thread about 4 times. A smart kid would get it after the 1st explanation.<br /><br />Is it surprising for you that a person who can cherry-pick pairs can introduce a correlation for the survivors? Is this "miracle" what encourages you to believe in your other nonlocality miracles? Cherry-picking or filtering is the process that is producing many/most correlations in the most general situations.<br /><br />The information isn't carried just by the particles. It's also carried by the door that may open and release them or not, and the wires that control these doors. It's this information that you completely overlook that is critical and where the correlation is created. All this information that decides about the subsequent correlation always propagates by the speed of light and every correlation always has events in the shared light cones of the relevant objects that fully explain this correlation.Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-21924667079382891032016-08-15T09:11:20.612-04:002016-08-15T09:11:20.612-04:00Andrei,
S1 does not imply nonlocality, but nonre...Andrei, <br /><br />S1 does not imply nonlocality, but nonrealism. Guilty of that :)Florin Moldoveanuhttps://www.blogger.com/profile/01087655914212705768noreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-72811636026708869992016-08-15T04:41:42.316-04:002016-08-15T04:41:42.316-04:00Florin,
"Not sure how you arrived at S1 and ...Florin,<br /><br />"Not sure how you arrived at S1 and S2"<br /><br />I have tailored the argument against Lubos'position, sorry if that was not clear. Nevertheless, S1 and S2 are the only possibilities available to explain the observed correlations. The spins are created at the time of measurement or they are not created at that time (they existed before).<br /><br />The argument is simple. If you go with S1 you have non-locality. It is a kind of non-locality that cannot be used to send a signal because you cannot controll the result of the measurement (Lubos claimed that any non-locality can be used to send a signal, so he is wrong on this one too). S2 is the local-realistic point of view.<br /><br />Now, Lubos wants the best of both worlds. He wants the non-realism of S1 (because he believes in free-will or whatever non-scientiffic reason) and the locality of S2. He is not merely saying that the spins did not exist before measurement but they do afterwards. He is saying that untill the measurement takes place, the spins do not exist, but after the measurement you can say, after all, that they existed even before the measurement. This is the contradiction. He wants to have two contradictory accounts for the same situation (the state of spins before measurement).<br /><br />As far as I can tell from your post, you go with S1 so you agree that physics is non-local. So, it seems to me Lubos was right to accuse you of pushing non-local ideas.<br /><br />Andrei Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3832136017893749497.post-45707152660380155912016-08-15T02:42:23.250-04:002016-08-15T02:42:23.250-04:00If J_z is the only property of the 4 spins that is...If J_z is the only property of the 4 spins that is ever measured, the entanglement works along *identical* rules to classical correlations of e.g. Bertlmann's socks, and that's why the discussion and explanations of all the correlations in these quantum experiments and their relationship with locality and causation are *identical* to the classical correlations, e.g. Bertlmann's socks.<br /><br />It's absurd that ER=EPR supports nonlocality. Just search for the word "locality" in arXiv:1306.0533, the ER=EPR paper. You will find some 10 hits. A big part of the paper - a key point of it - is explaining why locality isn't violated. For example, the paper starts with:<br /><br />Spacetime locality is one of the cornerstones in our present understanding of physics. By locality we mean the impossibility of sending signals faster than the speed of light. Locality appears to be challenged both by quantum mechanics and by general relativity. Quantum mechanics gives rise to Einstein Podolsky Rosen (EPR) correlations [1], while general relativity allows solutions to the equations of motion that connect far away regions through relatively short “wormholes” or Einstein Rosen bridges [2]. It has long been understood that these two effects do not give rise to real violations of locality. One cannot use EPR correlations to send...<br /><br />Maldacena and Susskind explain that the "violations of locality" in both pictures, GR and QM, are just apparent and no violation of locality ever emerges.Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.com