 Но все-таки, я думаю, начинка не очень важна для рекординга. В принципе, когда Тибо просил мне уйти сюда, я даже не показал в последнюю неделю, что я буду делать. И, в принципе, я сделал редакцию моей функции только вчера. Окей, и мы дадим так называемые «бла-бла-бла-ток». У нас есть уровень математического ригра. Но это будет связано, в принципе, с главным вопросом «бла-бла-бла-ток», если я понимаю правильно, с интерпретацией quantum mechanics. Но давайте начнем с «сгай». Потому что у нас были команды, нет экспериментных доказаний в quantum gravity, это, конечно, ронг, потому что космология, что мы делали сейчас, дали нам экспериментный доказатель в quantum gravity, реально в quantum gravity. Когда «Нью-Йорк-таймс» написали, что «байс-эп» реально был первый доказатель в quantum gravity, это опять ронг, в spite того, что в «Нью-Йорк-таймс»... Нет, в «Нью-Йорк-таймс», в принципе, не всегда правильные вещи. Окей, давайте быть дипломатически правильными. Потому что, если «байс-эп» «байс-эп» finding будет правильным, то будет показать, что два degrees of freedom of gravitational field are really quantized, just, actually, this transverse degree of freedom. But quantization of longitudinal degree of freedom, which is induced by the matter, was proved in numerous CMB experiments, because prediction of quantum cosmological perturbation series happened to be an excellent agreement with what people found on the sky. And because these people, who were looking on the sky, they had no idea, what they are expected to find, then we can trust them 100%. And not only because of that. These are thousands of people, who are involved there. So now, how is this kind of finding, raise question related with interpretation of quantum mechanics. If you start in very early universe, this vacuum state, for instance, for simplicity, then you amplify this state in the very early universe. Early universe is a great amplifier. Then, what you will get, you will get wave functional. Okay? Which describe, let me write like this one, all kind of configurations for the energy density distribution. The wave functional. But initial state is translational invariant. Right? Universe is homogeneous. Therefore, final state should be translational invariant. Now, what we see today on the sky doesn't remind any kind of translational invariance at all. Correct? So, for instance, if you will look, the Andromeda or whatsoever is located in particular place. And then you ask, at which moment translational invariance was broken. Because in the original result, if I solve Schrodinger equations, there will be full translation invariance. And here we have to refer to Mr. Bohr, because according to Copenhagen interpretation, I would say, or Bohr would say, I would never say it. Okay? First astronomer looked at the sky, and then he made reduction of this translation invariant wave functional. Okay? To the wave functional, where Andromeda is located in particular place. But in original wave functional, if you would expand it, of course, there would be all positions for Andromeda. I don't understand why everybody is laughing. Why? Because everybody says that if you will ask people on the street, not on the street, I mean physicist, Bohr interpretation of quantum mechanics. But as Braith David wrote once, people who say that they believe in Bohr say, that they believe in Bohr interpretation quantum mechanics, remind him American, who believes in bill of right, or American constitution without even reading it. So normally people have no idea what they are talking about, of course. And okay, now I will continue with the talk, which I think gave only twice, after I left Soviet Union, but in Soviet Union I gave it 300 times with the same success, so it means was complete failure. But then when I came in United States, I saw that it's free democratic country, as therefore, okay, physicist also open minded. And for instance, first time, I gave talk on interpretation of quantum mechanics in Brooklyn College, and it was just interview talk. As a result, of course, I collapsed my way function to the state when job disappeared, and everybody was running from me like I'm crazy. Perhaps they had reason. Now, second time, second time, okay, third time, it was 2003 in Stanford, there was conference paid by Templeton Foundation on multiverse and anthropic principle, but there was mostly physicist, okay, Lenny Saskin was there, Andrey, of course, Renato Tegmark was organized by Paul Davis mostly, and of course, there was one theologist, one philosopher, but here I make no comment. And then actually, I gave talk also interpretation of quantum mechanics after my talk I decided to make pool. I asked who believes in Copenhagen interpretation of quantum mechanics? Nobody raised hand. I asked who believes in many world interpretation of quantum mechanics? Nobody raised hand. I asked who do not care? Nobody raised hand. Up to now I still try to find good interpretation of these facts, because, okay, when I was doing similar pool, okay, among students in Munich, nobody, okay, 50% raised hand for many world, no, no, Bomi, I don't even mention, okay, because as Einstein said, okay, he doesn't want to discuss trivialities, okay, but, for instance, other thing, which was very interesting also, that in Soviet Union you understand that interpretation of quantum mechanics had practical applications, because it was ideologically important. And I will tell you two real stories. At the time when I started to be interested in it, of course, I found everywhere reference to Wigner-Frendt paradox. And reference was to this book Collection of Papers by Wigner, symmetries and reflections, I guess. Then I have Russian translation of the book. I went through it line by line, but I could not find anything like this one. And I didn't know why people refer always to this book, where I didn't find anything. But puzzle I resolved in 1988, when I went to United States for the first time and took English copy of this book. And then I discovered that two papers from this book during translation were kept. One was about nuclear disarmament, because Wigner had map, where in Russia were located all missiles. Everybody in America knew, but for Russians it was impossible. They prohibited to know this thing. And second paper was called Two Kind of Realities. You see? And of course Two Kind of Realities. And of course it was in complete contradiction with Marxism, Leninism, therefore also it was skipped. Moreover, how I got in this kind of affairs with quantum mechanics, I asked in 1984 I think there appeared paper by Hartley Hawking, and I told to my supervisor Markov, who was at this time I think already 85, that we have to invite somebody to give talk about interpretation of the way function of the universe. And then Markov told, come on, there is no in Soviet Union who really is specialist in this question and the biggest specialist Markov said he is. Why? Because in 1948 he wrote paper for the journal Questions of Philosophy about bore interpretation of quantum mechanics and Marxism, Leninism and he tried to reconcile both things and he did it quite nicely, I have to tell. And of course paper was approved even by KGB guys. But somebody perhaps missed something so next day or maybe in a week after that some official Russian newspaper, правда wrote paper about Markov calling him that his philosophical cantavros have horse, have human and of course what would be the consequence for Markov they already, his wife told that they already packed their things and were prepared to go to this Stalin concentration camp. So you see how important is interpretation of quantum mechanics. But again they were saved, why? Because Kurchatov called directly to Beria and told that if you will not leave physicist alone and if philosophers will interfere with physics we will not guarantee that this bomb which we are doing will explode and after that physics will exist in very well without philosophical intervention. As you know very well. Then also of course when I was giving talks it was always the same question. Ginsburg was coming to me. I again forget what is Schrodinger and etc. Why would I tell? Ok yes. I already reserved for you seminar in a week, 2 hours but of course during 2 hours I could speak only 5 minutes because after that all 300 people were speaking simultaneously. As you know interpretation of quantum mechanics and the arrow of time together with entropy makes everybody crazy. And everybody cares about it much more than about 26 or 11 dimensions as you know. Why? Because people take it seriously. But let me now go ok to something and remind you because Timo was speaking about Everett but he was covered mostly quantum cosmology Let me tell you what was known before Everett in fact actually everything including non-demolition measurement theory you can find in the best ever written book on the foundation of quantum mechanics and you know this best ever written book is von Neumann book mathematical foundation of quantum mechanics Everything is there concerning measurement theory, even non-demolition measurement theory and after that ok I will let what after that Everett and Bryce David added to this picture and there's a good example let me start with the example of Stern-Gerlach experiment because it's most obvious thing, very simple but it's very representative to explain all the main concepts which became very popular very recently in relation with quantum computers ok, so let me take silver atom located in some position at the beginning one silver atom so it's wave function which describe position then this is spin state spin up spin down be down and then as a spin how I do it in that direction I put here slightly in homogeneous magnetic field and then I send this silver atom within this in homogeneous magnetic field then I can solve Schrodinger equation because it's more or less trivial problem exactly and then what I will find happens with I know what happens with this wave packet here it starts to split in the solution of Schrodinger equation and then part of the wave packet goes up and the other part of the wave packet goes down like this one finally they do not overlap anymore then what you do next in the measurement of course you have to detect this atom then you put somewhere here for instance amplifiers or detectors like for particles connect them with wires with some kind of device what is device for me it's some kind of big thing which I can see with my eyes and which has pointer here before it will get signal from here or from here or if for instance it gets signal from here then pointer goes in this position if it gets signal from here pointer goes in this position but let me now include device also in the wave function of course it's complicated wave function in some kind of multi-dimensional many-dimensional Hilbert space but this Hilbert space you can divide anyway on the blocks for instance and say that at the beginning when pointer was here wave function for this detector was like D, 0 yeah this means not precise value of the wave function but it means that it belongs to some subclass in the Hilbert space for instance one electron can change situation but pointer will be still here it's microscopic thing then okay for instance pointer will go on the left side then wave function I will denote the detector has seen this thing in this position when on the right side pointer goes then it would correspond to wave function D okay down something like this one now for the fun also I want to include myself when I see on this kind of when I look at this device because I'm not very different from device I have not so high opinion about two kind of reality in my head, okay I am like normal robot nothing contradicts to this thing so let me write here also wave function observer and here I will write either 0 up or down depending what I will see with my eyes now I started some moment before experiment before the experiment began with the state okay alpha this kind of state which should be multiplied 0 okay to include device then after that it should be still multiplied by observer also which didn't see the state of the pointer, okay now if I will solve Schrodinger equation of course you can tell me how can I solve Schrodinger equation of degrees of freedom but in fact you know its solution because you know that if spin would be up for sure if this coefficient would be equal to 0 then pointer for sure would go on the left right and after that you just apply superposition principle to this kind of initial state and as a result of the unitary evolution what you are getting initial state alpha psi up its wave function which went along this up direction then you have spin up then you have detector which has seen or registered which had arrow pointer which went on the left and of course observer who is me who also have seen this arrow or pointer which went on the left plus there will be second comb better than psi down so its wave function normalized wave packet who went in this direction spin down then pointer head and pointer which went on the right and observer who has seen different picture for the pointer now what I got here I got here expression on the basis of which you can explain 3 or 2 most used now in quantum industry community notion like coherence entanglement so you see that after observation in spite of the fact there is no any more interaction for instance of the silver atom with any devices wave function is nevertheless not factorizable you cannot write it as a product of two wave functions in spite of the fact that there is no interaction its so called entanglement second thing how can you see the coherence you understand of course that these two states like detector spin up and detector spin down yeah wave function they should be orthogonal of course because you understand that this wave function do not develop or moreover if you have macroscopical device then if you will take two arbitrary state vectors in the Hilbert space they are nearly always orthogonal you see from here it follows that you have now de coherence so these two branches stop to communicate with each other third thing you can see here the appearance of schizophrenic state for the observer so I have to see simultaneously spin up and spin down and this is nothing more superposition of this thing this is Schrodinger ket Schrodinger ket is always there in any experiment you are getting Schrodinger ket in fact when I was speaking about wave function in the universe after amplifying this quant of fluctuation to macroscopical state I got Schizophrenic state of Schrodinger ket now what actually was the suggestion of I wouldn't say that it was boring okay, so boring was a lot of philosophical how to say 14 on the top of these rules which were formulated very well in von Neumann okay, von Neumann let me now actually just to save time do not write all the pieces of wave function just let's write misspin path which I am measuring so what von Neumann says after that okay until the moment when I was talking about wave function with macroscopical device evolution was unitary but a certain point you have to break unitary in the evolution why because otherwise you will find yourself a Schizophrenic state and nobody besides we think sick people isn't Schizophrenic state normally I cannot be simultaneously here and here therefore okay according to this von Neumann think you have to postulate that at some stage this wave function is reduced as a result of in this particular case of some kind of uncontrollable interaction not uncontrollable interaction as a result of some process either to spin up or spin down and this reduction here of course as you know very well happens with probabilities alpha squared and beta squared and this is principle in principle non-unitary evolution already this stage therefore sometimes I do not understand why people care so much about unitarities when they speak for instance in string theory about information paradox in the presence of black hole you have this kind of non-unitary evolution if you believe in something like many like Copenhagen interpretation all the time now where to put this place where you make this reduction as you have seen I can shift it for instance I can say that after splitting of two wave packets I can say that something happened and instead of two wave packets one just survived with some probability but it seems that there is no reason to say so especially if you are solving Schrodinger equation perfectly well then you say you can say that maybe you can refer this thing to the place where the signal was amplifying this detector because there are many degrees of freedom and you don't know what will happen but you have to realize that irrespectively what will happen it will not resolve the problem then the best way after many years of discussion which some people found they shifted this kind of reduction or this kind of non-unitary process in the human mind I'm not kidding ok if you will look it was precisely like this one moreover from Neumann ok this arbitrariness of the point where you are putting this kind of reduction called principle of psychophysical parallelism even you see in principle if you would say that reduction happened at the moment when two wave packets split it you still could doubt this thing yeah and you could check it happened or not happened and then you would find that you can put with the help of the other magnetic field two wave packets together and you would find that it didn't happen but when you move it in this big amplifier there is no practical as I want to stress practical way to check it you see because everything is very decaying because there is many degrees of freedom which are not under control just simply now if you put it in the human mind I don't know what you have to do you see you have to make interference experiment extra human minds and then I guess on animal of course you cannot do it because they will be defended immediately by some society but on human in principle you could do it but nevertheless practically it's impossible now what could be the possible resolution of this thing by the way Schrodinger actually when he realized this kind of thing he wrote that if he would know what would be the philosophical consequence of this theory I would never write Schrodinger equation Бор made so complicated philosophy I have read all the papers 5 years I was just studying this subject reading this interchange of messages BOR was writing so confusing philosophy which for instance I could characterize with two statements when somebody asked BOR what electron is doing between the act of emission and act of registration what electron is to be between act of emission and act of registration BOR said to be what does it mean to be itself of course it sounds very good but it doesn't reply it doesn't answer anything as you understand then after that there was discussion of separate classical reality and quantum reality what is the difference between quantum mechanics when I am teaching classical mechanics to the students when I come to Hamiltonian formalism I tell that this is great formalism you just put heads everywhere in these equations postulate PQ is equal IH and after that I leave you quantum theory for derivation as a homework in fact take sure after that you can get everything as you know and then you do not understand you think that classical reality at least as described by quantum mechanics as described by classical mechanics should be limiting case right? but here you are getting somehow strange things therefore the first way to escape from all these kind of paradoxes created the whole I think community also called statistical interpreters of quantum mechanics and by the way Einstein also was discussing this thing and people will say no, these quantum mechanics describe just ensemble of the experiment and the only prediction for instance which you are making for the expectation value of operator A which is measurable is nothing more than just trace rho A and therefore a function refers only to ensemble of experiment it's not the case why it's not the case because in quantum mechanics there are two kind of experiment there is experiments which you can make repeatedly on many objects which are prepared in the same state the other experiment is the sequence of experiment on the same single quantum object for instance imagine that result of the first experiment you found spin up after that you make second experiment to measure spin and then prediction is that you will find 100% probability spin up if you continues this measurement then spin up will stay always the same to explain these kind of experiment inevitably you have to make a function to particular quantum object otherwise there is no way to escape because the best thing say you can say still quantum mechanics describes it statistically right but I can nevertheless include myself also in the wave function right then if quantum mechanics describes statistically I include myself in the wave function then I should be also statistical object and there should be many copies of myself but I see only one copy of myself when I look in the mirror right where are all the other copies enough but even in this case I see only one copy but you see think how you can reconcile this thing statistical thing is good but where are all my other copies and then there is ingenious I think not ingenious really genius answer whichever it gave that what in reality quantum mechanics describes it describes the ensemble of many universes and particular definition of the particular universe is related with the fact that I am is I am let me elaborate this thing so if I will take this kind of attitude about reduction of the wave function is of course very unpleasant thing about which Einstein was very unhappy and he was telling what place dies and also he could not understand why device should be different in principle from the quantum mechanical object devices just latch from his point of view or we should be different but it was not main obstacle of Einstein and why he was unhappy the other obstacle was the fact that in quantum mechanics during practically any amplification process you are getting the states of so called alive and dead shredding gear cat you see what we know that these kind of schizophrenic states exist and we measure now why nevertheless we should not believe in these kind of schizophrenic states of course on practical side we cannot measure them because of the cahiness but nevertheless as a result of the solution of Schrodinger equation they come all the time and then you understand that after that Einstein try to make map between the object which you have or between the symbols which you have in your theory with reality so let's take this kind of state you know that if state would be like this one ok for Schrodinger cat you know that you have some universe where Schrodinger cat ok now I am drawing cat so we stay with this symbol then reality would be one to one correspondence with this symbol if the cat would be dead then it's again ok maybe not so great reality but you have here dead cat so until now it's very good but then as a result of Schrodinger solution of Schrodinger equation you are getting this kind of thing and there is no reality which would correspond to this symbol in spite of the fact that you got it as a result of unitary evolution and therefore of course you attributed to here or attributed to here but when you say you you are becoming the member of this process of attributing and what is our particular role in fact in our universe not very special you see we live in ordinary galaxy on ordinary planet and we are completely ordinary and Einstein was thinking that science really described nature irrespectively of us and he tried to find the law of nature and Schborr was writing no quantum mechanics is some kind of device which is helpful for our life and then Einstein of course as you know very well was telling that in this case I would prefer to be schumaker plumber even plumber ok so some people in fact sometimes translate Einstein also because for instance when Einstein about cosmological constant says that it was his greatest SLI people translated in English mistake blunder yes blunder but it's not blunder ok as you know very well but you understand that ok it was one of the very upsetting thing now what happened in so there was no one to one correspondence between symbols and reality and you needed always somebody who is alive, who makes sense out of quantum mechanics so it was Einstein was telling come on Universe exist without us and will still exist without us from the point of view of Bohr in spite of the fact that what I will say right now would sound have to say it stupid but nevertheless you can read and check from the point of view of Bohr if you would make logical conclusion ok all this Universe which existed in billion years makes sense only on our lifetime because otherwise what is the point to describe it especially if you start with quantum fluctuations yeah so now there is the other things also what does it mean classical limit of course we understand that if object is very large and stable then you can describe very well up to uncertain interrelations this object with classical mechanics right but in more fundamental way you should be able to describe it with quantum mechanics for instance take ball like this one ok 1 kg absolutely stable at the beginning wave packet for the center of masses like this one weight 100 billion years nothing happens with the ball right nothing happens because I just postulate absolutely stable I will solve Schrodinger equation for this ball what will I get in one 100 billion years I will get wave packet like this one so what does it mean this thing of course according to Bohr observer should come look at this thing and then make reduction of the wave function to one of the positions and he tells that the ball in principle could move to this position because you cannot fix precisely ok the initial moment because there is uncertain interrelation right but how you will be getting classical limit from quantum mechanical equations in this case how do you think the mass is very large mass is very large but nevertheless wave function weight billions of billions of billions of years wave function will become like this one very very widely spread and especially if there is some kind of potential here how you would get actually because according to so called R&F theorem I don't know what is if you will take some kind of positions then you have to take expectation value and then this expectation value should satisfy classical equation correct but after you will weight 100 billion years where wave function will spread anyway it will spread ok you will take this expectation value you will find that ok it doesn't satisfy classical equation but nothing changed it will start again to satisfy classical equation if ok observer will come and make out of this wave function with the act of observation reduction you see for instance one of the simplest examples it was again considered by Einstein sorry Slava I don't see why I cannot simply say that repeating measurement should give the same answer no repeated measurement will give the same answer why do I need to talk wait you measured first then after that you waited for very long time you got as a result of the solution of Schrodinger equation after that you want to take this something and still get ok classical limit because by definition our ball was 1 kg and was infinitely stable then you say ok you got wave function as a result of the solution Schrodinger equation without making measurements there and then how you would actually recover with this wave function classical limit which is very leastable would be many many atoms so you would have many interactions and you would have... no no no wait wait wait as I said let's consider ideal situation for a minute I don't want actually huge electron or something huge electron whatsoever you can write some object it's not real actually it's a big problem but nevertheless you have to get and as I said you can easily take one ball use some kind of amplification mechanism and then get for this ball one ball as I said wave function which has two peaks around two coordinates x1 x2 and ball 1 kg you see it's actually what Einstein hated he was discussing the example where the wave function of the moon has two peaks in the opposite orbits of the moon he was telling ok he has never seen this kind of reality but you are getting it very easily and here for instance if you denoted psi 1 and this one psi 2 and will start to calculate expectation values for instance if you had this superposition alpha psi 1 plus beta psi 2 then you can easily convince yourself if there is potential like x cube here then classical equation was x2 dot plus x squared one third ok is equal to zero now if you will take x in this particular case expectation value which will be psi x psi then of course this x bar coordinate will never satisfy equation ok you can add here terms which are proportional to the plant constant if you want it will never satisfy equation like this one Moreover you can check yourself that if you will take expectation value over this function then equation for x will be like alpha alpha alpha squared then here in brackets s1 2 dot plus x1 squared plus beta squared x2 2 dot plus x2 squared is equal to zero up to corrections proportional to h so you see what you got as a result you have big ball which wave function but you have just some of two classical equations what does it remind you it reminds you that this wave function describes at least two universes in which of which you have classical limit excuse me you take a classical limit and it shows you equation it's pretty well known that you have to do the right statement so if you write a classical equation that equation has a classical limit it has a meaning from the equation it depends what you take classical limit for Samsung it's okay you always have to do right thing and I am telling you how to do right thing therefore I can reformulate for you everything in terms of Hamiltonian approach even in terms of operators not in terms of wave function it's a little bit more convenient because otherwise if you no wait it's not confusing we can discuss it a little bit later but I am sure that a lot of people can start to object right now and then I will never end up as you understand I'm taking a direct book on quantum mechanics it's written how to take classical limit let me say the classical limit I did some check of the equation which decides an infinite number of classical that's correct but it's correct that limit of the equation which makes sense in the classical equation actually what I wanted to say very simple thing that you can make from quantum mechanics classical limit if you have large object for which you can define so called macroscopic variables which we discussed for 5 hours you can see but today is the go but you see you nevertheless has to do it in a smart way and here what I showed you when you have superposition of like this one for the ball 1 kg mass you have to make classical limit you have to assume there are two classical universes and in one universe ok you have the same equation with different initial conditions you see and moreover I do not see anywhere in mathematics why why universe should be preferable compared to the other universe you have again to bring more if you want to tell that one is realistic the other is non realistic you don't want to have so exceptional mind about myself that got created quantum mechanics for my personal use you see we are just normal robots somehow now whatever I did in fact whatever I did ever did great sync which I think was never appreciated even by John Wheeler you see because I am recorded I will skip a lot of quotes for instance when I asked once Ginsburg quote Landau about interpretation of quantum mechanics ok answer was not very diplomatic therefore I will not quote it here you know that as Landau normally say all these questions about Einstein paradox actually you have to address to board and then after that ok take board paper about Einstein paradox 30 pages blah blah blah as the end you are confused even more than at the beginning what I would say this is very good for political discussion right but this was the way how science should work now whatever I did therefore let me actually just summarize he invented what people called many world interpretation of quantum mechanics but the name I think was given by either Bryce Bryce gave this name so what ever I did let's write this schizophrenia state for spin up yeah so for spin up and then observer also spin up and plus beta spin down ok and then detector spin down etc etc etc he said that not only one of this system has reality but also this superposition has reality and in fact to what it correspond it correspond to many parallel world and in fact quantum mechanics in principle is the science which simultaneously describe ensemble of the worlds different worlds not worlds because we had very long discussion I think in some way in civilia with Gelman was participating should we distinguish worlds from worlds we have to distinguish it somehow but as you correctly say how much did you have drink before ok then it's ok and then whatever I said that in this particular case there are this way function describe whole ensemble of universes how many we can discuss separately we are in alpha squared percentage spin is up in beta squared ok multiplied by n universes spin is down and appropriately of course detector here is in this state in this universes in the other universes detector is in different state now if I would not include detectors I could not even define this world because after that rearranging basis for decomposition I could speak about worlds where spin for instance has value which is perpendicular in next direction now when the meaning of world starts to make sense only when there appears some object which we can recognize is macroscopically because we are macroscopical objects you see and in this particular case when I am distracting interference or I am getting decaherence the notion of world gets particular meaning otherwise you cannot speak about different worlds it's actually they are all together you see it's like the same thing different worlds in this case would not make too much sense because these worlds interfering too much you see for instance like statement imagine that you have two protons and electron makes one thousand rotation around this electron and then jumps here makes one rotation jumps back to this proton then you say that electron belongs to this center now if it would be different situation if electron would be making one thousand rotation here and then jumping here once you would say that electron belongs to this center but if it would be jumping between them you would not actually say this kind of thing now worlds are not completely non observable because if there is even decaherence there are effects which are proportional to the Planck constant you see and each of them you can just define making the decomposition of the wave function which describes everything in some kind of sum c n t psi preferable preferable n okay like this one which also you can take as a function of t by the way and then all this kind of preferable function you can define after identifying so called macroscopical variables which we can see with our eyes like location of the ball one kilogram right and then all this set of macroscopical variables I would describe by the set of operators m n yeah and then would request expectation values for them over the preferable by this component satisfy classical equation with the accuracy which is like ratio of Planck constant to the typical action which is related with this kind of process you see if I will claim that I want to get quantum mechanics classical mechanics as a limiting case of quantum mechanics then the set of ever at parallel universes is unambiguously defined now what we get as a result of this kind of blah blah blah for one and half hour first of all we are in this case we are not puzzled anymore with collapse of the wave function you are not actually as a result of determining spin up or down make any reduction you just discover in which branch you are located therefore no collapse no collapse so for the ensemble of universes what doesn't oh sorry I thought that perhaps I could give talk without microphone it would be more entertaining so ok good so now now ok thank you now in a sense science again becomes deterministic you take Schrodinger equation for the whole universe and you determine everything so it's you can speak for Schrodinger equation boundary condition problem because in Schrodinger equation there is no even time but this is not Laplace determinism because it describes you just deterministically the whole ensemble of the universes on one side is deterministic but on the other side you see you could have many parallel universes with the same past up to this moment of time but with different future you see therefore even if you know your past completely 100% nevertheless you cannot predict your future so on one side is determinist for the whole ensemble of the universe but you yourself identifying each particular universe when you go along your world line and ok your copies are identifying themselves differently but one of the important statement here that in for instance if quantum mechanics has reality and it has reality because it was proved by the measurement then all copies of myself are as real as myself I don't always say that they are real I say they are as real as I you see it doesn't mean I am real or I can imagine that you are all my imagination or maybe in the other parallel universe I am criticizing ever it perhaps but this is but this is but York this is very unlikely event so the number of the universes where I criticize ever it is extremely small now second thing ok we are getting one to one correspondence correspondence between reality and science you see I think it's also great thing is the dream of Einstein that science makes sense even in our absent and we are nothing more than just automats ok more complicated than even Japanese robots little bit now classical limit in each particular universe you always get when you have big enough object for which you can forget about uncertainty relation there is no obstacle about getting classical limit for macroscopical superpositions you just take one of the component of preferable basis and then classical limit you can recover in the limit when plan constant goes to zero because you should not forget that quantum mechanics is different from classical and to respect one is uncertainty relation and the other thing there appear all the time Schrodinger gets everywhere as a result of natural amplification of macroscopical event why some amplifier and this superposition do not disappear when you take h goes to zero Schrodinger get after you created it doesn't disappear after you took h goes to zero but on the other side to get Schrodinger get you needed to have at the beginning h non equal zero so third thing classical limit is well defined and I describe how to define now what about statistic should I postulate because I still have 5 minutes so should I postulate statistic or it's already there within the whole scheme here and what I will try to show you you should not postulate born rule you can get it somehow in a natural way very short nearly trivial calculation yeah but again no mathematical rigor see therefore do not just blame me for the absence of this thing but I am sure that we can discuss with you can make it completely rigorous good so what I want to get derives the rule that if my electron was in the state alpha up plus beta down then if I will take n electrons or silver atoms better to say in the same state then in the limit when n goes to infinity the number of electrons of silver atoms we spin up will be like this one and the number of electrons we spin down will be beta squared multiplied by n and of course here also because it's finite number of experiments I will have uncertainty how to call this arrow like square root of n correct because this alpha squared n makes sense only when n goes to infinity now let me derive this formula for that let me make experiment taking n copies of spin up alpha up plus beta down and cetera and cetera alpha up plus beta spin down ok and this should be multiplied by detector with n channels for all outcomes of the result of the experiment on each particular silver atom right but just to simplify formula you understand that you keep in mind detector but let's skip this term just for simplification if you want you can restore it let's write alpha spin up plus beta spin down in power n and let's write it explicitly what is this of course you know very well what is this because it's sum overall n then here alpha in power n beta in power n capital minus n and you have also sub sum this permutation all kind of possible permutation of spin up ok down and cetera but in this sum the number of spin up is n n n small and the number of spin down here spin up is n small spin down is n capital minus n now let's take this thing and say that it's a wave function where as a result of measurement you are getting n small outcome for spin up n capital minus n small for spin down and let's normalize it on unity then you know there's a number of permutations here is n factorial and then here divided by n factorial n capital minus n factorial correct now if you want to have this normalization for wave function square of course as it should be you have to divide this thing by square root of n capital divided by n small n capital minus n small factorial and of course appropriately you have to multiply this thing also by square root n factorial divided by n n minus n factorial and now let's look limit when n goes to infinity and let's take for instance you can take any power of this function square and then you will get here alpha absolute value and then what will be this distribution this distribution for the coefficient in front of the appropriate component will be n factorial divided by n minus n n factorial n n small factorial alpha magnitude 2 n beta 2 n minus n and you know also that alpha square plus beta square is equal 1 so what you got you got binomial distribution and this binomial distribution is like this one okay so it's centered when n goes to infinity it's Gaussian distribution with the center n capital multiplied by alpha squared you see and how bright it is precisely square root of n now you understand that when you take n goes to infinity limit then in this superposition only coefficient in front of the wave functions with the right statistic will survive all other will disappear and in such a way you are getting also okay internal description of statistic in this so called many world interpretation also now what became measurement last sentence so normally look I can tell you that I hate Lagrangian formalism and I just love Hamiltonian formalism because Hamiltonian formalism plus commutation relation everything is done for quantum mechanics, quantum field series whatsoever but there is one nice great thing about Hamiltonian formalism because if you want to have the series of non demolition measurement when you want to measure some quantity, it's human that your system was in eigenstate of this quantity if you want to do it on practical level it's very easy to formulate this thing in terms of the Hamiltonian formalism for instance actually in fact the whole series of non demolition measurement is made on prototype which von Neumann introduced in his book namely in the Hamiltonian you are adding the quantity gamma which is coupling constant x which is the quantity which you want to measure and some p where p is the conjugated operator to the observable which you can see with your eyes and von Neumann considered non demolition measurement for instance for the position of electron and using this Hamiltonian what he did he took electron in the same location 1 kg okay, introduce this interaction and as a result of this interaction depending on the strength of gamma electron stays in the same position but this big ball goes on the right 1 km you see so nice interaction but how to realize it practically is big question but from where you are getting energy from this coupling it's clear that for any measurement you have to have coupling now even for the measurement of electromagnetic field which actually was describing a very sophisticated way by Bohr and Zommer Rosenfeld where you have to have compensation mechanism you can get very easily in 3 lines if you start with Hamiltonian first as ever you go to the Lagrange where you try to realize the things you are getting them in 3 lines what is interaction? nothing special I am sorry measurement is just normal interaction like we all have okay as a result of which the things just amplify in this sense this kind of even non-demolition interaction is similar to amplification of this of quantum fluctuation in the early universe which gives us quantum mechanics which we see today on the sky so I started with sky and now I put the other brackets with sky I finish I like to question I mean I agree very much with what you say I have question which is not about interpretation but about reality do you believe that quantum mechanics applies to the extent that quantum computers will work I think it applies that is only technical problem the problem which I have with quantum computer I do not know what to use them for okay this is a different problem because what is quantum computer as I described it's like n computers classical computers which are working in parallel universes but communication between this which can pass from each universe only one divided by n amount of information and you have to pick up so called interesting information and actually the way how to pick up this interesting information is called quantum algorithm as we know very well and we know that up to now we have quantum algorithm based on the determination of period of periodic function including short algorithm then why its use of course if people would make quantum computers 10 years ago before they developed quantum cryptography we could solve all money problems of course because all the codes in banks could be broken within 3 minutes for that for what you are requiring for the normal computer how much time 10 billion years and it would be solved with quantum computer which consists of 200 qubits now with this quantum optics people went quite far already I think they have how many 10 or maybe 15 qubits 8 only 8 but 8 is already good because I recall that 15 years ago there was no hope to get even 2 or maybe 3 we were discussing this thing in this decaherence conference in Utrecht I think it will work the other thing not everybody needs it and moreover I do not know people who need it you see therefore people should work on quantum algorithms because its actually really from my point of view great area could be great area but since 95, past 20 years nothing principle in you compared to sure but I am not sure I have followed your argument about statistical interpretation but I heard recently maybe the same argument in a seminar on Zurich and he was claiming that all I need to assume is symmetry so suppose you take alpha equals beta equals 1 over square root of 2 then in a sense if I am going to put any probabilistic interpretation I better put a half and a half to the two states by single ok now if you accept this it sounds like a nice argument then you can easily generalize because you can just count cases is it this one perhaps what can be else in fact actually this whole thing in different form was invented already in 63 Finkelstein roses in 68 this is probably ancient but what you are doing is say there are n copies of your world and if n becomes very large very good York the only thing which I said that born ok max born got nobile price for this not derivation but for postulating that alpha squared is probability as you know very well of course most of the people most of the books on quantum mechanics that it's supposed to late if you show me one single book where these kind of arguments ok are presented and I agree with you but I don't want to surprise you with it as you understand it's just normal I mean people said the quantum mechanics applies to ensembles of many sort of identical copies yes you always say no I am sorry ok if you say that quantum mechanics is applicable only to n copies of identical system and if you are the member of the system then there should be many like you also then you have to make next step and admit many world interpretation right I mean since we discussed it let's not No, for the whole afternoon I think we fixed the things with a set of so called AS with this OS algebra it was different you see now we are discussing of course you can say that you don't care about your own copies in the other universe in principle I also can tell that I don't care our nice friend whom I don't want to I want to quote him but I will not name him he tells that about quantum mechanics shut up and calculate of course if you are enjoying just calculations shut up and calculate but somebody tells that sometimes you want to understand what is going on why we are calculating second thing you should not forget that all these kind of things my friend battalion told us okay he said like this one that equation should solve mathematician and physicist should formulate initial boundary condition problem it's our job and for formulation of this problem of course it's quite important to have right ideology I know it especially well because I have grown in Soviet Union I am in capitalistic world I know what does it mean ideology at the beginning of your talk you dismissed Bohmian mechanics and it seemed to be because it was a bit funny so my question is not why do you think Bohmian mechanics is wrong but why do you think it is ludicrous I will tell you if you take one degree of freedom you write equation Schrodinger equation let's continue the equation that you can put some word and then say that you convinced yourself that there is no problem now take two degrees of freedom and go to Bohm paper from 60 something it's already starts to look a little bit ridiculous but I can suggest you better things take quantum fields theory and try to implement this Bohmian mechanics okay interpreting what people call normally Toma Nagashwin equation so equation for quantum fields Schrodinger representation you will never ever make anything reasonable out of it also you write an equation and then put in the other collection of the words on it it doesn't mean solution of any problem when I said universes reality it's going beyond of changing of vocabulary you see what Einstein was telling about Bohmian interpretation it's better if you will read in Einstein yourself because he was not very nice with respect to the Bohmian interpretation you know what he wrote no he wrote that okay I'm not going to discuss trivialities yeah okay there are no more questions let's thank again Slava