incomprehensible quantum world my guest is doctor of physical and mathematical sciences, professor of the faculty of physics of moscow state university and head of the scientific group of the russian quantum center, professor of the russian academy of sciences alexei nikolaevich rubtsov alexei nikolaevich hello, thank you very much for taking the time to come to the studio. hello, thank you very much for the invitation. glad. here to be a premium. uh. given for experimental work using. as far as i understand, correct me better technology at the time of these experiments. and so, on the very, very aste of the possible, nevertheless, these experiments. they say something about hmm ours. views on the structure of

quantum mechanics, they also have a theoretical significance, what these experiments tell you about the nature of the world. come on, it’s very interesting, the nobel prize and it’s interesting, because it was given for the results that were obtained in the development of discussions and in the development of, let’s say, an analysis that lasted, well, i would say 100 years. yes, almost 100 years, almost 100 years, and in a sense experiments. sp - this is a test of bell's inequalities - this is the final chord or one of the final chords in the symphony, in which the main part is , of course, the discussion of einstein's boreas about the very nature of the world about the nature of quantum mechanics, its finality, as a quantum theory and specifically quantum properties of our world. the most famous of them is probabilistic,

nature, and physical measurements, what does quantum mechanics say, what did it say? bohr what is quantum reality that exists objectively and which is completely different from the classical perception of the world in which we exist, in which we think, a certain bridge must be built between these two big pictures. and this incomprehensible quantum reality is transmitted, and into our understanding through some laws, which are very difficult to accept not even what is on faith, but to accept their reality, to accept that they are really counter-intuitive. they go intuitive in their purest form, and not even our usual intuition, but the intuition of a person like einstein einstein gave in and said that it couldn't be wrong. do you think that einstein objected

to the essence of the probabilistic probabilistic nature of quantum mechanics einstein in no way doubted the quanto. a theory, because a lot of experiments by that time showed that the quantum theory is correct, but there is some deeper theory from which quantum mechanics follows as a consequence and which is simultaneously free from the probability of that choice is free from the probable choice. although we know that e quantum mechanics is any experiment that we do in quantum mechanics. he is the majority in the vast majority, the outcome of the same initial situation is unpredictable. oh predictable. only the probability that this this this or this will happen einstein hardly objected to this, and einstein objected precisely to this, he believed that relatively speaking, each particle is a kind of converter that is contained inside.

well, a color card. here is the color of this card. we don't know, we can only guess we can suppose that, for example, in half of the cards, eh? and inside the paper half is red. here's a probabilistic choice many grabbed. hey, an envelope. we don't know what color the paper will be. we say she is either senya or the red probability is 1/2 of both outcomes. let's make a complete clarification. as they say, the probabilistic nature is denied, and the probability comes from our ignorance. they are from the fundamental nature of the world just like that, but the devil or vice versa, another supernatural creature or artificial experimenter. he could follow. which pieces of paper were put in which envelope and would say no probability, in fact, in this sense, einstein denied the probability, the choice said no probability. in fact, there is no piece of paper of a certain color. its colors are

the hidden parameter of the theory, if we get to the bottom of these hidden parameters. we are probabilistic choice or minimize. i'm just e, i'll take this opportunity, the word non-locality will probably still appear today, and it means that you said when something that happens here affects something almost instantly. e, there i even said, yes, when there is some kind of supercomputer or ether, in general, there is some kind of out-of-spatial connection connecting all points in the universe and instantaneous time in violation of all lawful causality in violation. eh, so to speak, the rules that you can not go beyond the light cone and let's decide. we don't like it as soon as there are non-local hidden options. we say that for reasons close to einstein with his special theory of relativity. we don't like the theory with it's local hidden. we know that such theories can be constructed. but yes, this is not necessary simply because of the excessive

complexity of our picture of the world. is it possible to build theories with local hidden parameters , and at that moment bell appears on the scene, exactly like this ? prove that hidden parameters local hidden parameters. no, he came up with some equalities. actually bell's inequality which must be fulfilled for any theory with hidden parameters. that is, if, as it were, they say, ah, there are envelopes that electrons know about, but we don’t know anything, then, perhaps, using these envelopes, you peep what is written there. the electron will exhibit certain properties, and these are hidden parameters and thus.

he emulates. uh, the conclusions of quantum mechanics were talking and you said that whatever envelopes so that it is not written there. you can't, uh, achieve the same thing that quantum mechanics does. naturally, that's the truth. so i'm very conceptually high, but i'm giving bell's result because it's completely unusual, it's not a story about what can be done or how something can be done. this is a story about what can not be done. we will not try to come up with new hidden pair theories. we will define the properties to which any such theory must satisfy, i.e. here the inequality was this constraint, which any theory is forced to satisfy. using your metaphor, colored envelopes invisible to us inside there, no matter how these envelopes are organized, such a theory must satisfy a certain inequality. if they violate these famous bell's inequalities, then these envelopes cannot work. yes, these

envelopes cannot work or any basic principles, such as the principle, do not work. causality in general, in well, let's do it ein you won't get into your head. but how do we present ourselves einstein did not make such a theory that einstein liked , he proposed these inequalities in a theoretical article in the mid-to-mid-sixties. and gradually the question of the hysterical began to shift into the experimental not immediately. yes, needed here. e on the development of technology. e, he more or less immediately moved into the experimental plane, that is, bell's result was evaluated rather quickly, the leader of the group began to try to do the corresponding experiments. a, but really experimental technology was poorly developed not it was possible to make the experiment in such a way that its result was convincing, that is, free from interference, free from some speculative, but

strange schemes of introduction, but these very hidden parameters. in general, no one. for a long time i could not prove anything to myself or others, i could not do anything, but there were testimonies, but which were not proof. yes, and there were even works in which inequality was not violated. uh, in general, there was no consensus, there was no convincing result, but the joint venture proved everything to everyone, and he did, on really not a single job from a job cycle. he worked for two or three years and gradually improved and improved his installation. and let me try to talk about its main improvements, firstly, the hardware base, both now and then, to check bell's inequalities and in general to generate entangled states , pairs of photons are used, and that is essentially

quantum light, consisting of two photons flying in different sides, but confused with each other due to the common birth, due to the common birth due to the fact that they were yes born in the result of a single physical process. now the sources are so mixed up, as photons, rather very good and as jv did, as biphotons, as a result of decay. being in an excited state through an intermediate state, that is, a two-watt two-watt process, yes. through an unstable and intermediate level, two excited waves are emitted. well calcium, how many who aha how many who i honestly don't know what exactly is in his experiments. uh, used a, but it is important that he improved this technique simply

better in quantity, and decays per unit time in his installation were recorded, in my opinion, hundreds of decays per second. and that's quite a lot. this means that statistics can be collected in minutes, and a minute is a good time for an experimenter ; the parameters for setting temperature are time of day. everything, in general, is more or less stable; this result is easy to believe, there was no such thing before it. the tats have been accumulating for weeks, it is clear that during this time it is much easier to lose some initial settings. this is the first second the first is skillful, usage. ah. source of entangled photons. uh, and good statistics, that is, a lot enough a lot a lot a lot of inept use of creating a good source. suppose that with the known technologies of their

improvement, and the second - he was able to spread it, and the two halves of the bi photon are quite a long distance. these were meters, in my opinion, 5 or 6 m. why is this important this is important, because the time it takes for the source to reach the receiver, and photon a in such a scheme is already comparable to the response times of electronics, which was in his disposition. well, comparable here, you need a second, well, 10 nanoseconds. yes, it was in his possession. and this is very important, because it was very important for him to show that these photons really cannot talk to each other. well , it's speculative to imagine. here are two receivers, the circuit is slightly knocked down, one phototon is registered and when it dies, it sends a message

to another, telling about how it was registered. in which state of which in order for it to show collegiate properties means asp ruled out such processes simply, and changes in the experimental setup simply due to the fact that they carried them far enough away registration occurs simultaneously and accurately even at the speed of light, one cannot tell the other how it was registered. hurry up not immediately closed this loophole the speed of light. i understand that at first he was engaged in the fact that he had enough time to rotate the orientation to measure the polarization. this is the next thing i wanted to say. i am of course, uh, describing the last experiment in this series that everyone has already been convinced it means that it was still really important for him, but to exclude situations when, in some surprising way, in the process of radiation, the photon learns how it

will be recorded. and he did this in the following way. here at first speculatively he did not do so. there should be a polarization sensor there, and it would be necessary to make sure that in what basis the polarization will be measured, how this sensor will be rotated, it was not yet known at the moment when the photon is emitted. well, this, of course, is unthinkable, and the polarization analyzer is such macroscopic glass. and i can't turn back. yes, that's why he put two analyzers with shifted corners in each shoulder. and after that i put it in a circuit that throws the beam on one or the other and does it. this is already after the photons are deflated. thus. he definitely excluded knowledge. e of the emitted biphoton on how it will be recorded. well, at least in my

picture of the world, the three whales that allowed the tsa to really, but demonstrate to the world that yes, bell's inequality is violated, he caught a lot photons, that is, i accumulated all sorts of really good statistics, and the sources of error were two orders of magnitude smaller than the value at which the inequality was violated, and here it is, and after making a big stop with a large spread, i made this scheme with an instantaneous change in bases, in which it is measured, ruled out all sorts of, and speculation about how photons can tell each other in the framework of the theory with hidden parameters. so how they will be measured inequality has been violated. it's installed experimental fact, and as in the light. this is a reconstructed experiment of an experimental fact. you are a professional person who has to

imagine how electrons are endowed with those properties that electrons or photons, describing the entire system as a whole, we cannot say anything about its specific part, nevertheless, some properties come in this shoulders and correlated properties . in this shoulder, they acquire their properties, when and how , a biphoton is born either when a pair of electrons with interchangeable spinal components of the wave function are born and scatter in different directions. and this is really an essentially quantum thing in my third year, they taught me to describe it, but in the language of formulas, but in the language of words, how this word is described is quite difficult. and let me try again, and return to the analogy with envelopes. if there were hidden parameters, what

would such a pair mean in a world with hidden parameters, it looks like this we take, and one piece of paper is red and the other green is sealed two envelope. well, we shuffle, we send it in different directions to moscow and sochi, after that, having opened the envelope in moscow, we instantly saw it. what color is the paper there? what color is the piece of paper in sochi quantum theory says otherwise these pieces of paper have no color until one of the envelopes is opened, as soon as one of the envelopes is opened and they look. what color is this piece of paper ? is in another envelope. and if this envelope is opened. nothing after this new. we won't know anymore. you and i u said

uh invectives, and not in the address of locality. we said, we don't like locality. now it seems to me that you are faced with the choice of realism or locality. you must sacrifice something. either they communicate instantly at a great distance, or the properties do not exist, i don’t even know, regardless of what properties arise. at what point is there a principle of causality which says what if i have at a given point? and there is some knowledge. this is more accurate if i some knowledge in our system this knowledge cannot spread arbitrarily quickly throughout the universe at least at the speed of light, it must spread, so if i say, let this card be red, the knowledge that it

will not reach sochi as red at the same moment, it will be necessary to wait for the distance divided by the speed of light. however, besides my will, let's paint it red. there is also the will of the universe. which colors this card. so, when i measure its state in a quantum mechanical experiment, then there is, in a sense, a coin is tossed, and this coin comes up on the red or green side. so here is such an arbitrary, emerging information, and the result of a random choice can occur simultaneously at several points and occurs in experiments with entanglements. no, let's calm ours. uh, viewers on the subject of whether it is possible or not possible with the help of such non-locality, to transmit

signals faster than light, to arrange quantum teleportation faster than light and other things that are so desired in beautiful and wonderful films fantasy novels, and so on. how far this is from what science fiction would like. well, we , along with science fiction writers, too, of course, we want this is another matter, does it work or not? let me make it clear. no, it is impossible to transfer information or knowledge faster than light. the properties of quantum mechanical particles arise. at what point, if we have decided, i heard you so well that they do not arise at the moment of creating a tangled pair. i can only repeat, and the properties of quantum mechanical particles that arise in the power of probabilistic choice have the right to occur

simultaneously in different parts of the universe. imagine a situation where, relatively speaking, two people play in a casino, one on jupiter, the other on earth and a casino. this is arranged in such a way that red falls out to both absolutely at the same time, or black falls out to both of them absolutely at the same time. i heard you correctly that when photons haspelet from their point of birth to the detectors. they don't each have none of them have a specific polarization. nothing to say about her nothing. but as soon as we measured the polarization in one receiver, we immediately know the polarization in another receiver, moreover, the situation is even much worse for perception, polarization does not have to be only vertical or horizontal, the angle in which the polarization plane lies is arbitrary and as soon as we set the angle our

polarization meter and this polarization was measured. immediately, the polarization becomes defined for another particle in exactly the same coordinate system, so to speak, with the same rotation of the angle in which we we have, that is, it is not a choice between red green socks. and the choice that you are a very bad example, and they are a very bad analogy metaphor, and the choice between red green and purple and and. maybe even socks and gloves that appear at the moment when you look exactly like that, but very briefly, but quantum mechanics and we will experimentally study entanglement as a resource over the next ten years. there is no signal faster than the speed of light, but there is wonderful other technologies based on confusion, as a resource, if possible very briefly. we don't have much time. i would very much like

to still get something that looks like a working quantum computer, yes, but there is only entanglement. there are not two states involved. and at least 200, if we learn how to cook such mixed states with arbitrarily controlled characteristics, we will really have a revolution for this. i don't know how serious it is in our computing facilities. everyone is talking about your forecast. he is pessimistic let me repeat what i am heard from asp himself, he was in moscow about 5 years ago. he was drinking tea and was asked about the quantum computer. he said guys when i was young, when i was doing my experiments. i heard about gravitational waves. i understood that it was, in principle, possible to try them on. but it is difficult to imagine when they will be fixed, look,

40 years have passed. i should have caught them, uh, given the nobel prize. it seems to me that now the quantum computer quantum technologies are approximately in the same state as gravitational waves, at that time, respectively, give tens of years not 10 years, but tens. well, maybe technology. now faster and more funds are thrown into the creation of quantum computing devices, maybe in 10-20 years we will wait for them. i mean, not demonstrators. i mean , practically useful devices that solve practically important problems, the quantum world hides its properties from us. and actually. say that these properties are sometimes absent, but he also allows us to use these unusual unexpected traits in order to create high

technologies. thank you very much for your story. thank you. all the best, goodbye. it's always interesting how it all starts. now everyone will see the producers of good things want and most importantly. but it's best to check.

dear friends, i am pleased to invite you to our next issue of the besogon tv author's program, it will be called in the fire of the ford. no, i hope it will be interesting. i look forward to seeing you.

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