10:45:50 Thank you very much and Josephine I'm so since I'm the last speaker so let me for, especially for tank. Doug on MIT and Josephine for organizing this wonderful workshop, along with Lance and Ted, and all the audiences and they asked fabulous questions 10:46:00 and all the speakers. 10:46:02 So it was, it has been excellent. 10:46:04 You know, experience for masters. 10:46:07 Okay, so with this. And let me share with all of you what I have been thinking with some of my colleagues and about spin entanglement witness for gravity on. 10:46:19 So I'm from University of Copenhagen. And the idea is to collide. 10:46:25 Surely in your kitchen. So how do I collide for inject kittens, that's the kind of questions we have, we are going to explode. And the things which we haven't just speak today is quite generic. 10:46:35 You can use for fifth, fourth position just for low energy QED dark matter and various other applications which one can think about. 10:46:45 Let me also thank my collaborators with whom I have been working on this, and he just not spoken about his work and Casimir and fabulous things which we have learned from him, and my longtime collaborators who got to both with whom I have been bouncing 10:47:02 some of these ideas on and off for the past 10 years and. 10:47:06 And that has resulted in this collaboration, which involved. 10:47:19 Okay so, so what what we are actually after Soviet is a fundamental to your city, very humbled question, nothing very complicated but not very perhaps a very ambitious, but very simple question at the simplest level I want to understand the properties 10:47:40 of gravity, and the gravity is being mediated at the quantum level at the level of quantum field theory no spin to grab it on. So I want to understand whether they spend two grand on this tower mass, that if it's masters, what are the degrees of freedom 10:47:55 which propagates between say space time points. Does it have any Tachyon or ghosts or any kind of interesting, degrees of freedom so I want to understand these degrees of freedom. 10:48:06 Yeah. 10:48:09 And not only for general relativity, but you can also extend this to any high derivative extension extension of general relativity because you know that gr is derivative cherries must if it's master list is delegated theory, you can add for the terms 10:48:34 curvature, cubic order and hired a local and non local contributions. And so you can look at many many gems at the effective level. Yeah. So you want to I want to understand some of these aspects, but I want to understand also some quantum good relations 10:48:40 as well. 10:48:42 And as you know that any tensor quantity can be recast in terms of tensor degrees of freedom vector degrees of freedom scalar degrees of freedom, and this has been known since the days of Peter van new invasion and many other standards have discussed 10:48:56 this in 50s and 60s especially rarely worse when he was very lecturer at the Imperial College when he joined in 60s. 10:49:05 So some of the things which I'm going to talk about the techniques has been known for almost half a half a century. 10:49:12 Okay, so the basic assumption is very simple as the quantum field theory of gravity budget but you point them to do that. 10:49:20 So since we are working on quantum field theory framework so quantum mechanics and relativity are the only two important ingredient. We believe in the Litecoin structure nothing goes outside the Litecoin structure as well as information is concerned, 10:49:48 the origin of force and is essentially due to exchange of quanta example you cover, you pick up your karma prolonged interaction intense potential. So all these potentials and the non relativistic limit. We are imagining do to exchange of some sort. 10:49:53 So this is the basic assumption, basic underlying principle and based on this will discuss the rest of the top. 10:49:59 So plan of my talk is garbage on. Can I think about it as a quantum entity. 10:50:07 So, and in order to set up the stage, what I will do is that I would discuss the quantum divide for gravity. And then I will discuss the protocol which with Andy and Sue Got to have all involved in. 10:50:29 And, and then I discuss various experimental challenges there is no dearth of experimental challenges. And at the end of the day I'll discuss, we need a collaboration, which is really international collaboration because it's slightly hard to do this kind 10:50:43 of experiments in one's own law. 10:50:47 So what is the quantum device so let's say that we want to treat 10:50:53 matter pot and the gravity on equal footing. Let's say that we want to if we want to quantifies matter we want to quantify grab it on at least around the weaker which limit. 10:51:02 Okay. So, suppose. 10:51:06 So let's say, Vika which limit would be, let's take around mentors the space time. 10:51:10 And let's imagine for the timing that we want to discuss the non relativistic aspects. So essentially my Lagrangian is simply given by my mass of the particle which I'm going to take into account, and its interaction with me right now. 10:51:29 Let's place ourselves in a fairly normal coordinate system server nine approach. So, in this coordinate system is very easy to see how it's quite transparent to see how gravity interacts with matter. 10:51:44 And essentially interacts with your Phantom 01 components, essentially, and this is a effectively This is the interaction, and it would get. 10:54:19 Yeah, so it's good okay thanks Thank you very much. So yeah, so let's, let's say that we wanted to do matter and gravity on equal footing. 10:54:19 And let's say that we want to discuss physics around weaker which a limit around the list, let's say Mikulski space time because majority of the experiment which we are doing in laboratory space time is a fairly good you know space time. 10:54:29 And let's place ourselves in a, in a coordinate system of world line of my particle trajectory. So this is for me normal coordinate system. It's a very simple and convenient way to describe physics, special, and for the non relativistic systems which 10:54:48 we are discussing. So in this frame you. I mean you can know you can read the interaction between the matter and the gravitate on and you can actually then just assume the canonical quantization for rabbit on around them in the background, as well as 10:55:07 for the match. 10:55:09 Okay. Now suppose you asked yourself just a very simple question you asked that. Suppose I want to trace out all the matter degrees of freedom. 10:55:18 And so this is the interaction. And as you can see that this interaction is actually dictated by your connection with gravity, the interaction with gravity on, as well as your x square. 10:55:29 And you can see very easily in this effectively is dictated by Epicurus principle. As soon as x goes to zero the interaction effectively goes to zero, between gravity and matter. 10:55:41 And in this set of setup in this golden system. If you say that, look, let's trace out the magic degrees of freedom because that's the simplest thing which we can do perhaps. 10:55:50 And if you do that, then what you find very interestingly is that for the gravity on sector, you get a displaced vacuum. So displace coherent state so your comments, your vacuum state for gravity on gets displaced, essentially, and corresponding to this 10:56:08 displace current state, you get a number operator. So you can talk about the number of gravity ons associated with your system, same SM. 10:56:18 And amazingly, if you do this as a very simple calculation. 10:56:25 Down to Earth calculation. And so this is what I tried to show you is that we had a coupling between matter and grab it on. 10:56:29 I traced out all the matter degrees of freedom and I'm left with the purely gravity on sector, then the number of Gravity Forms, corresponding to this displaced vacuum amazingly release this quantity called GM square. 10:56:42 gz nutrients con constant m is the mass. And this, again relates to nothing but your area of your dark hole. 10:56:50 And again it rings the bell that familiar Bell, what you know our many astronomers have talked about holographic principle from top to and from also from many other people have talked about the holographic principle, but what it is you at the end of the 10:57:06 the day that the number of Gravity Forms is inherently connected with the mass associated with the system, you know you're associating with the mass is less than me blank same time. 10:57:20 I'm sorry, but the way you're talking about. 10:57:23 Because if you save the logistics system. 10:57:27 It's not accounting great and it's a, it's kind of instantaneous interaction, which is not counting any number of items at all. 10:57:40 Okay, yeah, it's good question let's come back to it, I will discuss now, I'm sorry, just to interrupt. Yeah. 10:57:48 Good that you asked me this question. Yeah. 10:57:51 So, the number of gravity fans in this context, as it was telling you that for a math lesson plan which is roughly genders to minus five grand is effectively less than one. 10:58:03 And for any astrophysical backhoes if you take it becomes very large. And so this this relationship is actually not completely new per se. It was first discussed by Buffini way back in 1960s, and then perhaps some of you know that Dr has been proposing 10:58:21 this idea of teaching Blackboard as a cop's color theory, and essentially when they're also you get the same relationship. 10:58:29 But in this, in this case he actually assumes that the black hole is made up of a number of graphic tones, and then he proceeds and shows that yes the Hawking evaporation rate, and many of the aspects of Bradford can be understood in this very simple 10:58:43 language. 10:58:45 But the idea is that the number of gravitas becomes very, very large, then what happens is that extracting the quantum information becomes also very hard. 10:58:55 So system, effectively geez like a classical almost classical. 10:59:00 So you can do the same game for just for the sponsor you can think about our universe on our land, and if you chase that all the matter degrees of freedom, effective it is given by this quantity which is again the same as we're discussing the back end 10:59:14 Steins bound satisfy saturates the vegan sandbox is given by Max and blank and the Hubble expansion rate, and if you take the today's Hubble expansion rate, you find the number of dragons would be humongous Lelouch so effectively our current universe 10:59:29 is effectively a classical system. 10:59:33 Okay, but this provides this also slim chance for doing some experiment with gravity. So if the mass of the system which I'm dealing with roughly is off the order of one party internet to five grams or even less than that, then the number of gravitas 10:59:48 in this in such a system is less than one. And there is a possibility that I may be able to extract some quantum behavior of gravity. Okay. some quantum aspects which we can perhaps explode. 11:00:01 So let's take a very simple example let's say that, just for argument's sake. 11:00:07 I take the mass of the system to be one Partington is 11 grams, which is smaller than one Partington is to find and number of gravity John's in this context is way too small. 11:00:17 One part intended to 12. 11:00:19 So let's do that. My apologies my system. I have got two bosses and gravity has to be lucky because it interacts with everything. So, you cannot scream gravity, like electromagnetism, so I have bought a red box and have got a black box. 11:00:35 And let's say that the size of the roughly delta x for our practical purposes the quantum experiment has certain size, that corresponds to delta x, and they're separated by distance d, but each and individual box contains some number of Grafton states, 11:00:48 but they're so small, but still they can interact with each other through some garbage on exchange. And that has to be some options exchange. 11:00:58 Okay. 11:01:00 Now you can ask the question, if this is the setup. 11:01:03 What is the phase, it will induce. 11:01:06 Well that's also easily to compute you can compute the action, due to the two boxes to do massive systems, you can compute the action which is given by your gravitational potential, and the time that you want to observe the system, and your husband. 11:01:23 And you see that supposed to as I said that if you take the master beautifully tennis to minus 11 grand just for the of course next example, you can pick up any, any such mass. 11:01:33 And you see that this quantity nothing is nothing but your number of gravitas stood in the system. And let's assume the two masses are the same. 11:01:41 Then you, then you ask the question, suppose you want to keep this experiment alive for roughly one second. 11:01:47 Because that's the kind of time scaly would love to explore a new experiment, then the, the size between, or the distance away from each other, has to be roughly hundred microns. 11:02:00 So that's the some landscape some rough distance we are talking about. 11:02:06 But then when can ask. Okay, so this is the face, you are measuring is a good be a classical face. It doesn't have to be quantum face, but when will it be quantum. 11:02:15 Can I can I talk about some kind of like entanglement face from here. 11:02:19 The answer is yes, you can talk about some kind of entanglement face, but then the way function of the two boxes, red box in the blue box, they have to overlap with each other sufficient overlap says that there is some quantum interaction, I set up some 11:02:33 quantum interaction. 11:02:35 And in order to do that, it will be clear later on that the, the distance delta x and d so the hierarchy between D index cannot be large. 11:02:45 It has to be fairly close to. 11:02:48 Yeah, I mean to each other. So delta x over D. 11:02:52 Of course it is less than one, but it cannot be very very smaller than one, if it becomes smaller than one, then effectively the two way functions, separate sufficiently enough that the overlap becomes smaller and smaller. 11:03:05 And as a consequence, the entanglement becomes also weaker and weaker. 11:03:10 Okay. So, with this bit of theoretical background, let's ask ourselves what kind of experiment would be like to do. Now, anything to do with quantum would involve perhaps spin, which is a very nice way to think about because it gives me a ruler, I can 11:03:27 talk about spin up and spin down system. And from the experiment his perspective is very nice because they can take diamond, which is a hydrant identity object and diamond has any v centers, so it's a defect, where they can place the electron spin. 11:03:44 So, it's a defect, where they can place the electron spin. And so, a diamond becomes your quantum system, a quantum dies, and I can rule the quantum dies, and I can talk about how many times I get spin up and spin down system. 11:03:55 And fortunately for such a system, our material scientists, they understand what are the, what is the Hamiltonian at least. So, the basic Hamiltonian will be which we know from the, you know, undergraduate days the interaction between the spin of a system, 11:04:11 and external magnetic field. Since diamond is a diamond you get material. So, in presence of extended magnetic field, it will also induce induced damage, the potential. 11:04:21 So these are the two important terms, where the spin can actually interact with each can see the external magnetic field, and the diamond can also feel the external magnetic field. 11:04:32 Okay. 11:04:34 Now if you want to understand a little bit of gravity on, just very similar in essence in the spirit wise is very similar to exploring that makes physics at LSE. 11:04:42 So our, our colleagues from the Higgs physics from Atlas CMS is the similar experiment. They are colliding the proton proton beam, someone can think about that. 11:04:52 Okay, they are also like Allison Bob system they are proposed my quantum system, I'm boosting in the center of mass energy roughly around 14 TV in the LSC. 11:05:04 And as a consequence, in this in the process of collision, I'm trying to understand the property of pigs. So what's happening is that, and the way I'm witnessing it is, why am I just one particular channel will be mine for left on Channel. 11:05:16 In the final leg I get the full leptons. These are this is the fitness. I can also have different channels such as default on channels and so on so forth. 11:05:25 So in the same essence in the same way, we can also think about suppose if I bring in two particles, Allison Bob, if I of course if I collect them. Of course I will excite some grab it on. 11:05:37 And the question is, by looking at the final stage. Can I figure out some properties of gravity, like whether the gravity on his master list or what kind of degrees of freedom does it have, and so on and so forth. 11:05:49 So, when it comes to understand these aspects. So, in a we need to rely on certain quantum properties like in old days in the left when people were talking about, you know, he blessing minus machine, they were talking about BACKWARD FORWARD scattering 11:06:13 events, and you know you could show the symmetry, and that was precisely because the, in the, in the case of electron machine, you have the Hennessy in the electrons sector, and you can compute this kind of like a similar similar kind of a symmetry, perhaps 11:06:22 me, maybe we can do it, even the case of gravity, so that we can understand, basically depending because now I can use my spin and spin as the head of city up and down, I can play district, perhaps, to see if I can extract some aspects of gravity on property 11:06:36 here on. 11:06:39 So, this is what I meant when I say that I want to collide the show ninja kitchen, so I can create now showing estate for my two masses, and I bring them sufficiently close to each other. 11:06:54 Of course this experiment is, I'm doing this, we're doing this expanding the non relativistic limit, but in principle, it can think about doing this experiment even religious chicken. 11:07:02 Nothing stops you from doing it religious you just give a boost you scatter the two masses, and then hybrid extremely extremely high energy limit, you can compute the staffing cross section, and you can talk about the spin states, and had a city states. 11:09:13 So, because of the spin, I can talk about. So this is my metrics, went from initial defining state. I essentially I have a right right so essentially left and right I have two states and corresponding, both the left and right I have a spin up and spin 11:09:29 down so I can talk about spin up, spin down down up down and down up so all possible for possible states I can construct. And as a consequence, I can talk about the normalization, and this is in the in the quantum information language this is known as 11:09:44 the magic state. 11:09:46 And people can compute the conference with this kind of state. 11:09:50 So, so this is essentially the experiment which we propose with our colleagues with Andy and so Gato. 11:09:58 This is in 2017, and also the same day there was a paper by black goo and my little from Oxford, they also had the same similar paper similar kind of idea, along with us. 11:10:11 So, in principle, you can compute the concurrence, or you can also compute the witness, but experimentally, it is easier to compute the witness, because you can say you have a system one, and you have got a system to now system money is a stronger lack 11:10:28 of politics system to is also stronger like apologists, and after the completion of the experiment, you're measuring the spin, spin up so you get a spin up and spin down so you can have 5050 probability, or you can have slightly different, like, up up 11:10:45 up down down up. So there is this, there's a way you can build a correlation between the spins and spins coming from the final state from system one, and the spins coming from the state of spin to. 11:10:57 And you can construct a basis dependent witness, and you can compute. In this particular basis dependent you can compute the entanglement whether the system is satisfied. 11:11:19 that at least the system one and system two are entangled and provided there's no other interaction, other than gravity. And that's the big big challenge and it's no no way one can achieve it so easily, but suppose if we can achieve it. 11:11:25 The only interaction between the two systems purely gravity, then we can say that at least is gravity on which we are talking about as a mediator has certain quantum properties. 11:11:36 So that's the kind of like setup we have in mind. 11:11:40 And as I said that you can compute the entanglement phase. And you see that the point which I was making the delta x here, cannot be zero. At the moment, delta x goes to zero, the entanglement phase goes to zero. 11:11:53 So the delta x has to be fairly close to deep. And so again, for if I take the Masters to be roughly 10 years to minus 11 Graham, if I keep the system a life of one second. 11:12:06 Then, the distance is I need is roughly 200 micron the closest separation, and the delta x, roughly 100 micron. 11:12:13 But, having said so. 11:12:15 The life is not easy because diamond is a. It also has dialectic properties. And given the dialectic properties, you can immediately say that, look, even take an exchange photons. 11:12:26 So this is exactly the diagram for essentially you have got a dipole dipole is here to diapers here, and the photon interaction and just go go. 11:12:50 actually and he told us that we have to be very very careful when you approach the distance of 200 micron, because the customer can be a big headache, and indeed it does become a big headache, because this policy being used entanglement phase, and the 11:12:58 Fancy meeting used entanglement phase, and the gravity on induce entanglement phase becomes fairly close to each other. So, if you want that at least gravity should dominate. 11:13:14 At least 10 times, then you have to make sure that, you know, these masses have to be roughly around, 1% and 11, and the separation has to be close to 200 micron and the text roughly has to be hundred million. 11:13:22 So, but having said so there are many many challenges there are many problems with the chorus, what has to be very very careful with the vacuum the vacuum. 11:13:31 In order to avoid any difference from air molecules or photons catching from absorption and emission of black body photons, the temperature has to be very very cold has to be very very close to downstate, and the vacuum has to be one of the best vacuum 11:13:48 he can imagine, perhaps the best vacuum is, you know, the sun can create the one of the best vacuum, where they collide the PV system. For example, this is extremely hard to achieve with the current technology, but maybe with the help of technology we 11:14:04 can improve. And there are many many problems associated with vendetta, you have to prepare your initial a package you have to neutralize an electromagnetic charges there should not be any past potential as Andy was discussing, you have to intentionally 11:14:16 cool because diamond has phone on you, even phone on vibration can destroy the coherence. The, the process that you are switching on and off the give you some noise, which you have to do you have to create the macroscopic superposition. 11:14:30 There's also a problem with the Humpty Dumpty which was first pointed out by Scully and trigger, and only the fact that you have to maintain the spin governance of the system extremely extremely well. 11:14:41 So there are many many headaches. 11:14:44 And you have to eventually have to read the spin states. And so having sister is extremely extremely non trivial extremely extremely hard experiment, but nevertheless, you know, it can be done in future. 11:14:55 There's one way you can screen the electromagnetic interaction. if you place a conducting, what, you know, pen conducting sheet, which can actually stand electromagnetic interaction so there is a way to stream the electromagnetic interaction here. 11:15:09 But God has but the two system can still interact via gravity via gravity, because gravity cannot be screened. 11:15:17 So there are certain advantages of doing this kind of procedure, but since I already lost some time because of this I will skip some of these things and we can discuss why, in, in the discussion session if you like, but and correspond to this we have 11:15:31 also studied the D facing and D governance and witness parameter, and all points towards you see the kind of temperature which we are talking about the internal temperature of the diamond has to be 0.15 Kelvin the external temperature has to be one Kelvin 11:15:49 But one of the things which are many of our colleagues have spoken in this workshop is about the gravity Greg is nice. So any experiment we want to do with gravity. 11:15:56 states extremely extremely daunting task, which we are talking about. 11:15:58 Gravity said becomes actually a big background and big enemy for us, because any image if there is a butterfly which passes by, will induce face to my system to my interferometer system. 11:16:10 If a snakes leaders, that will also induce a face to my interferometer system. And some of these things have been analyzed in the context of Lego and vertical, and there was a very classic paper by krypton, and his colleagues were there, he analyzed, 11:16:27 essentially, some of these noises gravity gradient noise, ladies, acceleration noises. So, in order to actually change some of these noises, what we realized is, you have to really take into account of seismic noises jerks the parts that planes passing 11:16:41 by this continuous motion. There's a, you know, marching. 11:16:46 You know, army people, or whatever, you name it, there's always a problem here. 11:16:52 So you have to really tame it. And one way you can tame it is to constructor dropped our experiment, because dropped our experiment, and what happens to this is automatic drawing and drawing. 11:17:04 The best way to go underground because in the underground you have a seismic noise extremely low. 11:17:10 And you can create in various levels various layers of your capsule. So inside the innermost capsule your experiment is happening, then you're surrounded by another capsule, then you put a couple of layers, so that your vacuum gets better and better, 11:17:23 and then you let it fall fee for Rafi say 5200 meters, because that's the place where the seismic noise becomes much much weaker. 11:17:33 So there are many many challenges but it also opens up a unique possibility of performing this kind of experiments, underground. 11:17:41 And this is one reason, perhaps some of these kind of experiments can be done so cheaply. 11:17:47 But having said that other kinds of challenges. How do you really create a macroscopic superposition of roughly 100 micron, and that itself is a big thing because no one has ever. 11:18:02 You know created such a superposition for masses which we are demanding Dennis to minus 11 grants, or tenders to minus 14 kilograms, the best. 11:18:08 10 is to minus 21 kilograms. So, we are talking about six or seven orders of magnitude of jump, and whether we can do it in technologically that's itself is a very big question. 11:18:25 And so some of the things which we are working on with our colleagues here from Israel, especially around Foreman's group. And this is a recent paper which accepted in science advanced, he was able to show that this entire fizzy it was just a feasibility 11:18:40 feasibility check that one can complete a one stone girl a clue that self was a challenge, and it has been recently been performed by his experimental group by Ron Paul man for a master fleet, one party tennis to 20 rats, still you see that we have to 11:18:56 have we require a huge jump and hopefully with technology, maybe we'll be able to reach the stage, and we want. 11:19:04 But, having said so the problem becomes very very interesting, it becomes exactly like the the acceleration, how would you accelerate the proton, or how would you explain electron in a in a in a, you know, like lead machine, or in LSC similar kind of 11:19:21 problem arises that here you need the acceleration mechanism to split the superposition. Even in the stun gun not. So you have to have a very interesting configuration of the magnetic field to create large macroscopic superposition at the very first instance, 11:19:37 and today actually we had a paper. 11:19:41 Especially addressing is exactly this particular point, that How could you get large splitting for a massive shortage of kittens. So, still be a very far away from what we would love to see. 11:19:53 So you can see that this is the mass range. And you can see that the splitting is still not what we would love to have for the to perform the gravity experiment, we would still need to do one or two orders of magnitude better, but in principle, it is 11:20:06 possible to take massive roughly suggest tennis to minus 14 kilograms, and you can get a split. 11:20:13 There's a split on the superposition. So in this scheme, we could get get something like 0.01 micron. 11:20:19 But we still have to go to 10 of micrometres is still a daunting task so gradually we are still trying to see how we can, you know, get this last position, and the, essentially, though, it's an open problem right now. 11:20:36 So here we showed that how to close the interferometer because one has to see the dentist parameter gets closed, you have to see whether you know the Humpty Dumpty problem does not bite you at the end of the day, so what has to take into account of all 11:20:47 possible fluctuations including the defacing including the de coherence FX and. 11:20:53 So just took for me to conclude because I have already spent some time already with my new essence of the iPad. 11:21:02 It is an interesting protocol it unites many many aspects of physics. 11:21:06 You see that you require cooling technology you look require material science from theory aspects unique where this fundamental aspects of quantum field theory. 11:21:14 You can even probe physics beyond the Standard Model like ACCION physics to some extent. 11:21:21 Andy already pointed out, you require atom optics chop chopping transitions levitation techniques. Kindness macro system comes in because after all, you're talking about cooling this, you know diamond and roughly at the ground stage and pull on vibrations 11:21:35 and all these things you need to gain us. You have a fantastic victory then probe Casimir effects on new fifth force in this process, because of whatever I have said, you can also use it for even for charged particle charge superposition. 11:21:51 And you can prove the fifth force, or you can do very low energy venture of DVD experiments, so it opens up many many interesting avenues for physics and definitely we would like to see big labs, such as Fermilab or CERN some of these facilities can be 11:22:06 it can be useful, which is fantastic because the kind of vacuum which we are talking about all these, these formulas sunken ever produce mountainous to minus 15 Pascal of dentistry my 16 basket. 11:22:19 And here comes the you know the adventures taken by Jerry, and is called a colleague in northwestern was really was pioneered one of these subjects how to create one of the best vacuum in world to do these all these kind of experiments. 11:22:42 So I think it's a, it's very important for us to now think about some kind of international collaboration, it opens up various doors for how to create this massive split for massive system law splitting up quite extreme technology, a cooling and back 11:23:08 hot, but nevertheless the many things which perhaps one can do in future. So with this, let me thank all of you. Thanks for your patience, and I'm really, really sorry that I had to take a break couple of times with my iPad. 11:23:22 Thanks. 11:23:24 Thanks, and have a very nice talk. 11:23:26 Yeah, so we'll open it up for discussion. 11:23:37 Yet, Jake. 11:23:41 Thank you so much for that conversation, there's actually a lot going on and. 11:23:47 And I'm not certain what's talking about these VG and political issues but going backwards Hello there. 11:23:54 Can you hear me I can't hear Jake. 11:23:57 Oh, 11:24:00 is that better. 11:24:03 Now, I can hear Jake. 11:24:06 All right. Yeah. 11:24:10 Good. Well anyway, I'll say it and I can also type it in chat, I suppose. 11:24:19 The main question I have, has to do with coming back to the idea. 11:24:20 What do we mean by gravitational superposition, and how to quantify the size of it so you're proposing a metric which is what you call the number of rabbit towns. 11:24:33 And I guess it'd be, it'd be kind of curious your thoughts about how that metric works in some of the other types of experiments that had been proposed over the course of the last few days. 11:25:50 Yes yes we can hear you. Okay. 11:25:50 Thanks Jake thanks for asking this very nice question. So in some sense yes you can think about is like a metric fluctuations, the number of parameters here is kind of like metric fluctuations. 11:26:02 So if you imagine that if you're, you know, if your system is not very heavy, if you if you don't saturate the limit where the image of your of blank. 11:26:15 And then, essentially, you're, you're talking about system of gravity which is very weakly covered essentially the number of parameters which are exciting is very very small in some sense, 11:26:33 Arkady. Sorry, before rk speaks. So, on your palm Can you can you hear us. Can you hear everyone. 11:26:43 Okay. 11:26:47 Oh, sorry. 11:27:03 Okay, so. 11:27:06 Okay so that is a problem. 11:27:13 Yeah, maybe our Katie if you could just speak, ask a question and then maybe also type something to on your palm to communicate it to him because he can hear us. 11:27:25 Yeah. 11:27:25 I'm repeating myself, you know, I asked him during the moment when he mentioned gravy gravy dance. 11:27:34 Yeah. Here, here. 11:27:38 I disagree with a point to call it gravitas because what they what what is called latency is counting the local like number photons whatever for gluttons is, is the same. 11:27:51 And to say that, for example I am I getting the election is exchange or four times. 11:27:58 It's a, it's a little bit too much because in some way. 11:28:04 That is relation between instantaneous interaction and exchange baby of photons, indeed, but it is Lawrence invariance it's about. If you are not talking about sacred the chicken locality. 11:28:18 In, including what in some ways, but there was an interesting something is interaction and, and to call it, small or large not bow gloat and said believe it is not available, okay but but I led asked it so So, and the formula, you know what I'm asking 11:28:34 about right. Good, thanks thanks for the night in here. Unfortunately, maybe it was the internet connection from my side. Yeah so okay so. 11:28:43 Okay. 11:28:46 So I got it, I agree with you and there is also there is some amount of disagreements so I can tell you both. 11:28:59 So take an example of forgetting gravity, no no You said you should choose as you agree or disagree. Okay, so we are discussing physics. So let's say we want to forget gravity for the timing, we wanted to say electromagnetism QED experiment. 11:29:09 Let's say we take a molar sketching sketching is also like one, you know it's a photon exchange. Now, of course, you can say that from your knowledge. 11:29:18 It's not an exchange, it's what I'm trying to make a point, it's not an exchange. If you have non OTC system. 11:29:28 Okay, let's say, Fine, I agree with you. Let's say that for the timing that is instantaneous. 11:29:36 But even in more in a more less caffeine. I can build up my Hello city states, and I can talk about how the hell is it is are entangled. He needs to classical. 11:29:48 Here is your part, but not actually still forums. 11:29:52 Yeah, exactly. Hey, this is your party but not the football. Yeah, absolutely. And that's what I'm at I'm happy so even if I take instantaneous. I can build up entanglement between velocity of electrons and compute my forward backward scattering. 11:30:10 So, sorry. 11:30:15 No, but you know, but look at this in this interaction between say speeds are you is you can space it it's also in circumstances but of instantaneous interaction. 11:30:19 No. 11:30:30 So, I respect that. But what I'm concerned with not about instantaneous or feel what is important for me is a spin correlation. Right. 11:30:39 But you, 11:30:41 but you call it now Bob Jones anti disagree music terminology, if you like, you should not call it number gravy thumbs. 11:30:49 Okay. 11:30:56 I can call it some other way, doesn't matter. But what I, my first half of what I was showing, suppose if I chase out all the matter degrees of freedom, whatever you call it. 11:31:05 Look, I am not arguing against this a McKinsey when you call it a number of ladies don't send you if it's kind of misleading terminology. 11:31:16 Okay, what would you like to call say for instance, what you can say is it it is a MTG autopsies gravity field or whatever you can call it any way you like. 11:31:28 Right. But, I mean, but, but when they say, blame it on that you are lady implies that you can, you know, you could propagate and agree with them and it is not something system so that's the beauty, beautiful thing that we are talking about self gravitating 11:31:44 system. So what okay you may, you may not call it number of gravitas you can call it number of states, but number of states of gravitational fluctuation if you like you can call it about. 11:31:57 It's not about fluctuation. It's what I'm trying to say it's not alteration propagating rotation it's what is global, but something is proper greens whistleblowers to life, and it has its own he needs to close this up. 11:32:14 But, but when you're describing the interaction, it is this kind of, you know, you call it, sometimes I'll shell whatever so so it's not to come to go and keep him in terms of number of a great a great game of thrones exchange this, I do my sense is correct 11:32:42 There is no that savage got saved go popcorn how to live Kevin wait that was repealed or whatever, but it's a freedom, it is it's a real degrees of freedom and state, I can compute my correlation, there's nothing stopping me from writing a good addition 11:32:59 here I've written it energy, but I could have done easily number, the correlations to one correlation I could have built very easily. 11:33:06 But I still can call you not to call it. Number. 11:33:11 Number. 11:33:12 Because if it's misleading. 11:33:14 Okay. 11:33:23 Yeah. 11:33:32 What is quantum right like what is quantum because you had, like macroscopic masses right. 11:33:38 Yeah, you see the blind which I mentioned to God to assume. You don't have to go for gravity you can do even in QVD experiment electron has a healthy city state so I was, what I'm interested in is to build a correlation quantum correlation between the 11:33:51 healthy city states. And the way I built the hell city states in the gravity is by putting the spin in my diamond. So how about spin up and spin down system. 11:34:01 And now I can do an experiment where I can look into this, the gold rush and spin coalition states of maybe just repeating what is the thing Alyssa states all. 11:34:15 Yes. 11:34:19 Innovation exist. It's a classical wearable. 11:34:27 So So you use this calculation right but you do not. 11:34:32 Okay, it's not forgotten. 11:34:32 It's not about content, Quentin quantization Glenfield. You know there is, there is a difference. This is the classical level correlation and quantum correlation. 11:34:42 There is a difference 11:34:47 is the case because you can just, kind of, you know, in Gravity, for example, both charged, and local church mass and spin interaction, a fixed by experience principle. 11:35:04 So in this way. It's a lady of the classical level. So it's an action item is already classical. 11:35:10 Yeah, but in the classical correlation, you will always get 5050. 11:35:24 And this you can do the calculation, you're talking about quantum of nature, or particles or not, it's not about quantum nature, and he'll know but what is important is that if the gravity is classical, the spin correlation will always be 5050. 11:35:30 Okay. 11:35:37 I do not understand this. Yeah. Yeah. Just a classical billiard will never entangle the two systems, this is the whole point is for you for this unique one so you're saying that to that action of potential between in quantum mechanics classical I disagree 11:35:53 it's quantum. 11:35:56 Okay. 11:35:57 Okay, so let's, let's move on to a more general discussion.