10:44:58 Great. 10:44:59 Thank you very much, so it's my great pleasure to announce the last speaker of the, of this morning session that is john g from Gila knees and University of Colorado Boulder, he's going to tell us about his exciting work on clock quantum manager and fundamental 10:45:18 physics. Thank you very much john Dune for joining us today. 10:45:23 Thank you, Anna Maria I presume you can see my slides Yes, Yes, yes, everything's working. Well thank you, and Doug and Josephine for organizing this bringing the community together to catch up virtually. 10:45:38 And I also want to thank Dave, for such a fantastic talk, and of course the Mariana, that makes my job a little easier I will focus a little bit on the neutral Adam side off the clock. 10:45:47 One thing I want to add, you know really emphasize, I think, Mariana said that during her talk is really exciting time where that quantum Science Advances. 10:45:57 The, the precision of measurement frontiers, which brings us this discovery potentials for fundamental physics. So, if I made on, let's see. 10:46:10 Let me start on this in our building a clock, you emphasize on coherence as Dave mentioned, use the coherence to advance precision allow you to check all the systematics, and in right now, the community of quantum science and the majority are working 10:46:25 together to to get entangled states into the capture of clock making as well. 10:46:30 to get entangled states into the capture of clock making as well. So, so all of this, of being able to do a precise quantum state preparation, maintaining quantum coherence to optimum clock measurements and so long. 10:46:41 Allow us to advance the precision frontier. At the same time, of course quantum science that's getting a very exciting stage people want to build a quantum computer quantum information science building systems with large scale quantum systems in tangled 10:46:55 resources will be used, and adapt together, of course is advancing the quantum science volunteer, and you can see this volunteers are merging and creating opportunities for fundamental physics. 10:47:06 And since we were talking about coherence let me actually somebody asked that question about coherence. Let me just give you a very quick sort of a animation of the time scale of the Columbia talking about University has that changed to the 18 seconds 10:47:19 of 15 billion years, a quantum pendulum and such as what they've talked about single track that in has as you heard from him and it'll quantum pendulum period typically on this time skill femtosecond tend to the minus 15 second, you take a geometrical 10:47:33 meaning of those two extremes of timescales you leave you arrived that is a timescale which was quite sensible we human experience. In the case of strontium Adam so we actually have coherence time. 10:47:48 The atomic a lifetime of under 60 seconds in the in the excited to clock state. And we are pushing now quantum coherence to a matter of a minute. At the moment in the laboratory So, so this is getting to a point where you know you can think of a pendulum 10:48:03 swing out of the entire lifetime has a quality factor of 10 to the 17, that happens to be the same quality factor that one second of the time elapsed. 10:48:13 In our human experience verse, the entire age of the universe. 10:48:18 And the clock being a connection of the space time. 10:48:28 Fundamentally, provide this new opportunities to probe, whether its existing physics, but it was new capabilities, or beyond standard model of physics. 10:48:35 And this is what Maria and I talked about in in her spirit of the seminar. What I'm going to tell you a little bit about, is it a possible we can advance close to the level of st tantamount is 21 so on, where you can start to see the curvature is of space 10:48:49 time inference, the main body entanglement. 10:48:54 Can you be able to close to probe space time ripples, such as gravitational waves. 10:49:00 You, we already heard talks about using clocks to put an upper limits, and eventually by making clocks bad and about 10 miles 21 building a network of those. 10:49:11 That won't be able to constrain the document and maybe eventually discovered the existence of document or through other thing astrophysical observations. 10:49:23 So, so I would say the clock really provides us a giant telescope, allow us to look into the universe, looking for gravitational waves dark matter, but also provides a high rate of low resolution microscope looking back on Earth, and looking at all these 10:49:37 God. 10:49:38 Gravity effects and relative relative of psychiatry obviously and so on. 10:49:45 So we have seen the summary of the clock elevators over the time and optical clock has clearly surpassed the microwave based the time standards, and now by currently by two orders of magnitude. 10:49:58 And you can think of all of this advances are. We can think the technology development over the past two decades, and a number of them, which made the enabling breakthroughs. 10:50:12 Why is a high quality factor optical transitions we heard from Dave is I'm going to tell you about your items. 10:50:18 New laser stabilization now, allowing you to build an article called heroes. For many 10s of seconds. 10:50:25 For many 10s of seconds. We can put Adams ultra quote Adams in optical lattices engineering anybody quantum states. There's optical frequency frequency calm that allows you to connect article phase to the microwave face and so on. 10:50:38 And all of that contributed to the current clock, state of the art of measurement uncertainty attendance 18 level, and the measurement precision not approaching beyond one part tend to the 19. 10:50:51 And I think that certainly it's very exciting that we as we move towards gentleman's 20 tournaments 21 beyond that, there will be a lot of opportunities coming out of these clocks, for, for fundamental physics. 10:51:04 Just a quick slide about the current state of the art of stable lasers. These are built on silicon crystals, and you're cool these crystals down to a zero cost them on zero crossing temperature off of the material, these, these cavities are exceedingly 10:51:18 stable. In fact, we have been tracking these cavities for over three years now. Each each day, it moves the frequency of by two hertz and we know exactly how much it moves to a with a with a residual uncertainty at the level of fuel plus 10 to the 17 10:51:38 And if you beat to such independent cavities together and you can actually reveal the coherence of these new stabilizers here shows the language of eight megahertz hundred 51.5 micron weirdness already. 10:51:54 So, to just give you a scale off, people mentioned about building networks in space. 10:52:00 Lasers like this now can span a distance over hundreds and millions of kilometers, and he still maintains the face coherence in fact Earth to the Sun, the distance is only a minute and, and if the face coherence, time is exceeding a minute or approaching 10:52:16 a minute. This is heading up astronomical scale that you can maintain optical coherence you can't allow you connect the two satellites and maintaining their formation of the Flying together. 10:52:30 And Dave mentioned this key aspect of success of a single trapped iron clock, where they were able to enter this thanks to the menu pioneers the mentioned deployment as one of them. 10:52:43 The idea. The basic idea is that you can separate the internal degrees of freedom from this clock states ground and excited state, and the excellent degrees of freedom where the motion or degrees of freedom is quantization. 10:52:57 And as you drive the transition from clock ground state to the excited state, the emotional degrees of freedom is a well controlled by doing that you remove Doppler from the o'clock transition. 10:53:10 You also remove the photon recoil effect. And you can you can do this, do that such as the trapping itself. The act of the very act of the trapping the particles is not influencing the frequency measurement you're making between the two clocks states. 10:53:24 And now of course in your items, we would like to expand this to multiple particles because the more quantum particles you use in your clock, the better the position what improve by a square root of X number of particles to us. 10:53:37 Yeah, and this is not even talking about quantum entanglement. If you can implement entanglement or spin squeezing, then the improvement is goes further beyond the square root of the particle numbers. 10:53:49 So, so this is the really the recent advances by holding atoms in the so called a magical light ball, where the basic idea of using optical tweezers holding atoms in the, in the track formed by the optical beam itself is a symbol it's been being here 10:54:07 for a couple of decades, but typically an optical track would result in a state dependent position dependent state frequency shift that would say for the atom was actually traveling the optical trap the actual optical frequency of the clock transition 10:54:25 is no longer accurate, but if you were able to find a particular wavelength of a particular species where the optical trapping potential can be engineered such that both the ground, and the excited o'clock states experienced the exact same is sofa a stock 10:54:42 shift. They can essentially achieve similar conditions as we have heard from chopped onions weather trapping potential for the most relaxed and emotional degrees of freedom is then disentangled from the internal degrees of freedom where you're driving 10:54:57 the clock transition. 10:54:59 And once you achieve that particular attracting condition. 10:55:05 The rest of becomes that relatively simple. You can have it. In fact, you can have a single laser beam going being reflected by a mirror that forms a standing wave in the so puddle, forming a one dimensional optical lattice. 10:55:14 And you can visualize this as a stack of pancakes where each one of those can have a dozen also atoms trapped there. 10:55:22 And that's the place where you can use precision spectroscopy, to just tell you that you know the dramatic effect of combining these atoms in optical lattices. 10:55:32 Let's start with Adam in free space, and it will you have cool these items, down to a temperature offer just a few Michael Calvin, and yet you still have the Doppler broadening of your 10s of Keller has just because optical frequency is such a high. 10:55:46 It is such a high value. 10:55:48 But as soon as you put it, Adams into a shallow article is that a discussed in the previous slide, you can immediately see that as you probe the top row transition of these items. 10:56:15 a little deeper and a little bit deeper. What do you start to see is this look the development of so called emotional side events, the language that we learned from trapped I am community. And the idea of course is very similar where the emotional degrees 10:56:18 of freedom, along the trapping. This is Johnny confined directions prioritized, and you can try to transition on so called a carrier where the, the harmonic emotional quantum state is not changing the quantum number, but you can also drive the so called 10:56:32 Data n equals two plus one side band, this is the color blue side band, and the separation between the carrier and blue side when equals exactly the top frequency of atoms that can't find in these optical lattices with emotional degrees of freedom, and 10:56:48 is also on the blue side and on the red side and sorry. You can also drive the motion or quantum number from one to zero, for example, under the so called a minus one. 10:56:58 But if the Addams I want to do. 10:57:01 Cool to the emotional ground state, of course, then the sexual rest IBM disappears as you can see there's a profound asymmetry between the blue in a race I've been spending some time on this because later, I'm going to come back to the idea of how do 10:57:14 we, quantum state engineer, these, these atoms in the emotional degrees of freedom. 10:57:20 So, so now you put these bunch of atoms in the individual pancakes, as I visualized here, and you can zoom into one of them, and as you start to drive the clock transitions, of course they are coherent state, the light field is driving the spin sort of 10:57:36 spin half system. Putting them from so far the blogosphere from initially pointing to the south pole to the equatorial plane where you have a coherent superposition putting down in the Upstate. 10:57:49 And then these atoms are left in dark state for a while, where you watch how the clock is evolving, the individual spin is evolving with respect to the rotation frame of your laser. 10:58:02 But if these items actually interact with each other, these items we picked up with a firm yarns. And you have to the Air Force, and he summarized the wave functions. 10:58:12 Nevertheless, if you have a long coherence times, even if the two atoms cannot have the so called it the symmetrical emotional degrees of freedom interaction the sofa, so every interaction you have to have an odd partial waves, or the odd cemetery ization 10:58:29 of the special degrees of freedom, because things are in the total, total symmetrical state. 10:58:36 In this case this interaction is much weaker than the for the particles what's Rosen as a firming balls arms, but nevertheless because the coherence time we're pushing is for multiple seconds, those very weak interaction still gives rise to the interaction 10:58:51 shifts in fact that we can actually see this those individuals things become entangled the quantum fluctuation become correlated. And you can actually describe this as sort of a system spin that that has been caught a single access twisting whether it 10:59:09 is szu represents the collective of spin degrees of freedom of all the atoms. And it turns out by the coordinating their spring degrees of freedom, you will have for this quantum noise in twisted, as you as you probe the clock transition. 10:59:26 So this gives rise on one hand, interesting, degrees of freedom to entangle these items. On the other hand, it gives rise to frequency shift, unless you're completely understand what's going on with this entanglement generations in squeezing process, 10:59:40 well as lost in the in the process. So, this led to two possible directions one is make really big to the pancakes, where interaction goes to zero, and I'm going to tell you some very recent results along this direction, or you will make a really tiny 10:59:56 3d cells where atoms are quantifies to such a high level where interactions so large and that themselves becomes monetized, and therefore can be well accounted for in the transition. 11:00:10 So let me first talk about these 3d firmly lattice clock that basically ideas very simple really. 11:00:17 By cooling the atoms to very low temperatures and build article that is not in one dimension, but in also the dimensions, with the fermion. You hope they will be able to use the potty exclusion principle where one Adam occupies at one site that followed 11:00:37 And if you just do a daydreaming about scaling up with a quantum system, you put 100 by 100 by 100 optical that is this one atom per site. If you have a coherence time of hundred 62nd, you can actually reach the precision of a few plus 10 to the minus 11:00:54 20, and it just the one second of average in time. This is the fact of thousand better than the current record that we hold, and it was second it was three times 10 minutes 17. 11:01:06 And the same similar ideas of course, gives rise to it quite an interesting with this is a very densely packed quantum material, and as you drive these things. 11:01:16 There's a real interesting questions about Fermi Hubbard model. How do you deal with these relative with energy skills of tunneling verse, outside interactions with Holly blocking for me statistics and so on. 11:01:29 So it's actually turns into a real interesting quantum simulation platform to understand some of the outstanding Hamiltonian in Congress metaphysics, in yet we are turning this into an exquisite sensors are fundamental physics. 11:01:43 And I also want to point out this type of approach has now inspired this full up working optical tweezers. This particular pictures were taken by Adam Kaufman's group inshallah, where he was able to do both one dimensional or two dimensional optical to 11:02:11 arrays, to push the coherence time. Also in the strong using strontium 88 ball Sonic systems to a few 10s of seconds. Maybe I would skip this slide, this is just talking about is using SEO aim to prepare single for me see at a very, very fast speed timescale 11:02:22 so that we can have a single, single spin Fermi's the system was 10s of thousands of atoms was was temperature for me temperature was temperature of overwhelming temperature of point oh seven indicating strongly or deeply degenerate quantum systems have 11:02:38 a single string, single nucleus being quantum systems that we are ready to love these atoms into the three dimensional optical artist and and so, so this is the picture of ideally you want it to one atom per site. 11:02:53 And if you do that, you'll do clock spectroscopy, you cannot observe three sets of savings that I mentioned on the emotional side bands earlier. You have three different distinguished assignments because you have a three dimensional space, and all three 11:03:07 dimensions are quantifies was the emotional degrees of freedom, and there's no expectation level on the red side of the on the spectrum. That's because the atoms are pulled cool down to the emotional ground state. 11:03:21 If you're worrying about that we didn't do a clean enough job that atoms were left with multiple nucleus beings strontium at seven forgot to mention has a nucleus being nine half. 11:03:32 So when I mentioned earlier have to spin polarization going to a single nuclear spin that you can you can visualize this as you know one single color here but if you are the spin for purification is not a is not 100% complete the other items, or it can 11:03:58 by different colored balls left in the system that in principle these atoms to not have to have a party expression principle that because they are distinguishable. So you're putting these atoms in the optical lattice, they can cause frequency shift, as I mentioned earlier. 11:04:05 Fortunately, because they are your confinement is so strong, the interactions with distinguished fermion, so strong that they are, in fact, separated from the main carrier, which, that's why I called a quantifies interactions and turns out, as long as 11:04:20 you're anti semitic much for eyes away functional between two particles which can come from either the nuclear degrees of freedom, or from the electronic degrees of freedom, energy represents ground and excited clock states. 11:04:36 So the total wave function is always at summit rise, but it can come from either nuclear or the electronic degrees of freedom and that that manifested as to see bands of one to one side. 11:04:55 these side band has frequencies of a few kilohertz. Why are the carriers can be made as narrow as tans Milla hurts. So they are far offset from the actual clock transition, and they no longer cause in your frequency shifting effects to the clock at the 11:05:08 at the level of 10 to minus 21 tenements 22 level, we actually go beyond just having visualization of two atoms in one cell we can actually have 345 atoms in these cells, and all of these interactions that can, as you can tell, a contest and and turns 11:05:28 out you can have both cemeteries, or anti summarized way functions of with respect to the nuclear degrees of freedom, gives rise to always to see bands, corresponding to either to Adam parasites three albums of society for Adam society, etc. 11:05:52 and all of them are well separated from the article carrier way as you're driving the clock transition, the interaction effects are no longer important in this case. 11:05:57 And it was so a single nuclear spring state, whether we are working on right now is to create it so far the band insulator clock, where the clock, are the latest is occupied one Adam parasite. 11:06:10 And then we have a clock laser that's driving the transition. The clock laser wavelength, and the loudest wavelength is not necessarily equal, just because of the wavelengths that we use to chop down on a given by this condition of ritual so called a 11:06:24 magical wavelength, where the ground and excited state is the stock shift the matched that we have lenses different from the clock laser that we probably the transition itself. 11:06:35 So therefore, if you put it Adams just now you believe between the lattice for the for the lightest sides, that's formed by the lightest laser and then pro by the clock. 11:06:46 You can see the between site to site you can have a face shift because the wavelength, the key back to off the probe laser of the clock is not measuring with the lattice spacing. 11:06:47 The way winners are not necessary. 11:06:57 And if the lattice is confined at a much shallower depth because we're trying to remove any ramen scattered process that's limiting the coherence time that, then the atom can actually tunnel and it because between the enabling sides they pick up a different 11:07:14 clock face shift, they become distinguishable from yawns and the so this process can actually be to frequency shift. So we are working on ideas such that such like. 11:07:25 You can make the wavelength of the clock laser, which that's fixed, but you can make the spacing of the optical lattice to become measure it or to be missed in this picture showing basically equal to the wavelength of the clock laser itself. 11:07:40 And as Adam jumping back and forth, you pick up no clock is a phase shift in doing so, you maintain this strictly Ben insulator regime to allow you to reach very high coherence time and that these are schemes that we're working on. 11:07:56 to. to drive the three dimensional optical ladders clock. 11:07:59 You can also image. This is a technique we we just, we came up with us. 11:08:05 You can combine highest spectroscopy resolution and high spatial resolution of a microscope together. And in this case, for example this is three dimensional optical it so we can apply a magnetic field gradient. 11:08:32 That gives rise to a frequency shift between that is cell by cell, and you can use this imaging techniques to actually map out the frequency shift of the optical atoms of the these atoms and combining optical lattices here the measurement position with 11:08:35 a few years ago, was this up three dimensional optical lattice reach the low parts of tender minus 19 in a few hours and new measurement capabilities we are not advancing will allow you to reach this level in just a few 10 minutes. 11:08:52 So this gives rise to this dream of extreme space time resolution. Is it possible, the fact that that Earth is, you know, we're not talking about Jake Taylor was talking about gravity. 11:09:04 Of course not. But we are talking about is curved space time, if we can start to make a colossal added the level of measurement precision of 10 to 21. 11:09:26 That was respected elevation on top of the earth. And now you have to treat these manually entanglement. and anybody stays under the curve of space time. 11:09:29 That would it be quite an interesting new regime of probing the connection between quantum physics and a gravitational physics. It's not a, it's not a quantum gravity, but it is a, allowing us to actually probe the curve to space time quantum entanglement, 11:09:44 which is a new 11:09:48 was that the three dimensional space, clock, it's still quite a, quite a year, quite a years away, to be able to reach that level of precision so we we we thought about, well let's take the other approach where you have one dimensional optical lightest 11:10:03 and we're just going to make a really really large pancakes, remember there was two different strategies so we're going to take. 11:10:09 So this is a newly rebuilt Joe strontium when we actually had a gentle stretching one system is our workhorse system for the past 15 years and this was the first system I feel when I became an assistant professor at the time. 11:10:22 In the early 2000s, and we just recently rebuild a system to make the really large pancakes and and the key idea is to put a, an intro vacuum lattice, that's being supported by a cavity. 11:10:35 Using cavities to build an optical now this is not a new French group has done that, my group did that a few years ago Angela the last group did this. 11:10:44 Also, but the What's New is actually this cavity is really inside the vacuum was very high finesse. And we because of finances so high, we, we designed the system such that the pancake is actually very large here shows, almost half a millimeter as as 11:11:01 a, as a diameter of these individual two dimensional pancakes. 11:11:06 And, and we were able to trap actually almost Adams, this optical lattice is also extremely long vertical experience, more than a millimeter. So that's a larger system. 11:11:19 In fact, and it is here's just some beautiful photos when we're putting a system together. 11:11:24 Near the end of last year. 11:11:28 So, one thing, one thing that we see immediately is that the traditional optical loudest clock that we have been working on this for many years, oftentimes have these so called a blue and the red side and I explained earlier, as you're cool the temperature 11:11:41 down, you can see the right side and disappears it's still there, a little bit. The blue sometimes it gets a little sharper and, and people may ask why the site bands have such a line shape. 11:11:55 And that's because in the transverse direction, the atoms are still hot, they have not fully quantities. And so there's emotional degrees of freedom that's coupling between the longitudinal direction that's astronomy combined direction, and the transverse 11:12:08 direction that gives rise to these smeared out say bands within your system, allow us to cool the system down, much better and you can actually see not individual emotional states are all separated out. 11:12:21 And in fact, if we cool down a little further. The red side band went from the trees shorting red to blue, where the basically there's nothing in the right side and now in the blue Simon, essentially comes down to that single emotional degrees of freedom. 11:12:36 And the blue side, essentially comes down to that single emotional freedom. And if you probe in the transverse dimension, the temperature has been lowered by a factor of 10. 11:12:47 Typically now sitting at a few hundred, hundred 50 natural Calvin also a temperature that's comparable to what we do in the three dimensional optical is the wisdom he system. 11:12:55 And it's a really interesting picture that we have now starting to operate these optical as because atoms are so cold and very very shallow trapping death. 11:13:17 a single record energy to describe how deep the loudest is. And typically we would be operating something which is a four or five times higher than this one and our recent work even pushing this down to 10 he recoil. 11:13:27 In this case, we have seen some really interesting because these atoms are scaled vertically, you will hear more about it of course in Adam interferometer work tomorrow. 11:13:38 But here you see this block five and these are the atoms that is moving back and forth due to the gravity. In the article that is, and of course individual pancakes are spaced apart, it was energy was a gravitational potential energy of MGHH is a separation 11:13:54 between the pancakes. In this case limit over to lambda the optical wavelength, forming the optical Alice. 11:14:01 These are these blocks it winds up exceedingly coherent and in fact. In one experiment, we can use clock to measure gravitational potential, and we can use this optical block size advance to measure gravity. 11:14:14 It's not yet competitive with Adam interferometer. 11:14:35 like. 11:14:35 Yes. 11:14:38 Perfect. Perfect. Okay, okay. 11:14:50 Oh, do mute yourself. 11:14:57 Yeah, I'm sorry, gentlemen. 11:15:01 So, this is what I was going to say this is actually the image of the lattice spectroscopy in the vertical direction, you know the atoms are the lightest extends about a millimeter, and he can do these two different regions, you can image, different regions 11:15:12 and you can look at it for example the image, the top half as the bottom half and look at the coherence This is very much in the same spirit what Dave talking about in this the same lasers driving these quantum coherence and you can compare different 11:15:26 regions so you can see there's a strong correlations between the different regions, yet is effectively removing the visa know laser noise out of the picture. 11:15:35 And if you, if you do that, you can, for example, you can actually plot that the correlation between the top region was the bottom region. And you can actually see extends this all the way out to 40 something seconds, you can still see coherence between 11:15:50 the top and bottom regions of course, in the end, we should be able to go all the way out 260 seconds. That's what the clock years time should be given by the by the lifetime of excited state, but there's some other mechanisms that's limiting us for the 11:16:03 moment, but nevertheless. This is a really exciting to be able to push through this long coherence time with thousands of atoms at once. 11:16:13 And the technique like this gives rise to actually the individual systematic accurate evaluations across entire sample. We used to just make a one single measurement out of this ensemble average, but now you're looking into the guts of the clock, you 11:16:27 can actually see pancake by. Well, not quite pancake pancake, but you can start to see pixel by pixel. What is the frequency shift, and you can cancel that. 11:16:36 For example, this is the density shift as a function of the counting numbers and you wouldn't know. You went in just a long shot you're starting to measure pastiche of attendance is 18 level. 11:16:47 And, and it was this, just the one to have a one slide to tell you, this gives rise now a new capability of being able to measure 10 to the minus 919 level of precision, one time Cinemas 19. 11:17:02 In less than one hour and and this is a really exciting time that we want to see actually a gravitational redshift within this single article itself that's a millimeter scale up the corner. 11:17:16 This will have a redshift across the sample. One part 10 to the minus 19, was that I think I'm going to end here actually prepared some slides about fundamental physics but but it since Mariana and Dave or they talked about this I don't need to the accepted 11:17:33 the only difference I was going to tell you, was this cavity, Adam comparison provides, allowing you to push the energy scale to the larger mass in what they've shown that this allow you to push the corner up to the, to the larger document a candidate 11:17:49 mass. And still, and I think it was still have tons of room for improvement to continue to improve on this exclusion limit for the dark matter. 11:18:08 I was going to tell you a few slight field, few slides about the VOB calm for the nuclear clock transition but since I ran out of time. Our in here. Thinking manual for the graduate students and postdocs, as well as many collaborators from PDP from just 11:18:16 from Anna Maria, of course, Mariana, Misha looking Peter solar and so on. Thank you for your attention. 11:18:24 Thank you for the very very nice talk is so now we are open for first some questions about the particular talk and then we start broad this question of the last two or the overall the session this morning. 11:18:41 So please just, you can raise your hand or just speak up yourself. 11:18:52 So this is Jake I have a short question. 11:18:54 Go ahead, please. So June, you talked a little bit about looking at the curvature of space time. 11:19:00 And I guess I just want to get a sense of, you know, how is it different than seeing redshift and what's what's really the new physics that you have john bell. 11:19:09 Thanks. 11:19:11 Excellent Jake, um, yeah actually I think the difference really is at a man your body level, if you have a single particle. And this is all nothing but redshift. 11:19:22 And as being able to measure redshift at the level of millimeter of course is very exciting. 11:19:27 The DLD and it's on the fox I like that is very excited about that. But, but what's really interesting to me I think will be when you start to have it within that pancake. 11:19:37 Yeah, you'll build entanglement. And the link between pancake pancake pancake to the actually have this in a different gravitational read redshift potential. 11:19:48 So, so will be interesting to allow you to have these packets to be tunneling back and forth, and watching how the hell how the entanglement survives. 11:19:58 During that kind of a code of space time. So that's different from single particle redshift. 11:20:03 Thanks. 11:20:05 Great. 11:20:07 More questions. 11:20:13 Yeah, go ahead. 11:20:14 I have a related question actually so in your proposed experiment, and this is amazing work and it's very exciting to see this new strontium one clock. 11:20:26 How would it actually manifest itself so you have fewer different pain cake levels, and let's say you have entanglement in the system. And so, what do the signature would be. 11:20:41 In this case, offer in your think which is, which you don't expect. 11:20:46 I would say if you if you cheated on you know suppose you do not assume there is, if you do this experiment in International Space Station, and away from the gravitational potential pole they, I would imagine the coherence time or the entanglement time 11:21:05 In the end, if you understand if you treat the problem with the proper reference frame with coats space time probably there will be no surprise. 11:21:11 is actually different from when the curved space time is there yet. 11:21:15 you can run your lattice clock horizontally, where the individuals pancakes will have no gravitational redshift was verticals, where you have the individual pancakes half gravitational Asia. 11:21:34 Yes, your measurement precision actually reach to the level where the block observation is occupying you know 10 sites or hundred sites with all the hundred microns. 11:21:47 We are not quite there yet we only reach to that community meter at the moment, then you will have, I would I do if you're just naive retreat as a flat space time. 11:21:53 There's two systems will display a different entanglement dynamics. 11:21:59 Very interesting if I if I may, a related question, but in the case of sort of the next experiment. When you can actually see, perhaps, just a shift the big difference and hide buttons, you know parts of the pancake. 11:22:19 Can you directly compare some frequency in a different ism punky sites. 11:22:25 Yeah, that's actually what the there was a plot I went through so fast I didn't didn't show, but there was a plot with, I was averaging down to 10 almost nine. 11:22:35 Well, basically just one times 10 of us tend to minus 19 first thing that was not a single pancake. That was a collection of pancakes about hundreds of pancakes list at a bar at the top. 11:22:52 those two regions. And that I think is starting to be really exciting in fact that you can do that you can also compare all these other, we actually did the first thing we get in the back in January this year was, we were able to categorize all the magnetic 11:23:06 magnetic field gradient we never were able to just at the level of 10 almost 20 level, I showed a a b squared home, but uh, but I didn't really have time to go into it but these are the effects that we can show that at a high precision. 11:23:21 That gives you a more sort of a confidence they are systematic uncertainty because we are seeing the entire neighborhood. We're not just reporting a single number. 11:23:30 Now, at ensemble averages single number but rather exploring. Not only that single number but also the gradient around it. 11:23:52 And it's only one last question if me let me come in one related to that kills Mariana to something that we have been thinking in that direction. So, June will have in his in his optical art is different of mm, the classical mgh difference, but these 11:23:53 in principle with accumulate a different face, but in their presence for example of the wave or his wave interactions, there is going, also to be at the coherence effect from these interactions. 11:24:04 So the interesting part would be see we can model these with the classical flat space and try to see that ego curious how these a, the coherence will change. 11:24:13 For example, if, and if, for example, we need to really include corporate space. I mean, if there are gravity I mean we can do it with fixed gravitational potential. 11:24:25 But if something might happen is that we have to have it that batteries from side to side. So that would be I mean this is still classical and not quantum but if you would really need to start to corpus space that they g changes, not, it's not costing 11:24:43 the radical changes that that could be very very exciting. Just a comment now on that. Those very exciting. So, in the list of practical question for the thing D it takes a generally a longer time to prepare as a larger so that type of the longer. 11:24:54 So what about this new strong film, strengthen one clock there's no such a large largest what's at that time would be. 11:25:02 If you have is one ensemble. 11:25:05 That time right now is, yes. So, what I spoke about is this coherence spectroscopy, which is what Dave also talking about that you try to look at the correlation between the top and bottom region so you can sort of remove the laser noise out of that picture, 11:25:20 but if you use this whole entire system to compare supposed to be able to have those, and I start to compare them, then this actually goes to what David showed again. 11:25:30 The this Boto clock network where you have the clock laser would be caught up in the noise process. And, and it's sold the duty duty cycle is what limit limit as duty cycle is essentially how long you need to prepare the quantum samples. 11:25:46 There are different techniques out there you can, of course, in one will vacuum chamber you can prepare to such quantum samples, so that you can alternate when you're using sample a the sample be prepared. 11:25:58 You go to sample bu and sample is being prepared so so there's just a new quantum resources you can you can assign to the system to remove the doubt time, Andrew. 11:26:07 Andrew does a lot had done some of that work already. 11:26:12 The current that that time we have is about. 11:26:17 Once second in preparing the entire samples, but not as we push the coherence time to 10 seconds or longer. At that time becomes a less less of a problem but it's still there. 11:26:27 In fact, anytime you stop the, the laser evolution that introduced at that time because the face is being disrupted. 11:26:35 So, so that's something that you know eventually I do think that at that time doesn't have to be a problem. 11:26:43 And it is a technical problem practical problem, or one can find the practical solutions for it. 11:26:48 Thank you so much. 11:26:51 Thank you, Marina so I see him, eager, there is a comment that you want to make I see it in the chat, but I don't know if there was supposed to be for discussion or 11:27:05 maybe 11:27:09 will always be great to hear Eagles discussion point. 11:27:17 Yeah, I don't know if he's muted or. 11:27:21 Okay. Well, we can continue tomorrow in principle that they apply we have different days of discussion. So him, but I mean, still we have more time for for a boat or, I mean to discuss all the talks in the morning if we want a way to party a sorry, go 11:27:41 ahead and please ice to a two people with hands raised please just start speaking, please. 11:27:50 I have a question about. I mean one of the issues in precision gravitational physics is there's been a. I mean differences in the measurements of Newton's constant. 11:28:02 Is there any prospect ID and a inner from, I mean, trapped ions and, and so on can improve that. Of course you'd need to be sensitive to gravitational fields produced now by the earth that by some piece of matter that you could weigh separately. 11:28:22 I'm not personally aware of any proposals using trap Diane's for making a big g measurement. 11:28:29 But that could just be my own ignorance. 11:28:33 I I can't say I thought about it. 11:28:37 But it's very daunting. I think you're too small, you know, that's why. Earth is still irreplaceable. Yes, additional field is great, you know if you, if you get the entire Earth concentrated in a ball. 11:28:54 And, you know, not Rocky Mountain kind of size and you're playing a clock nearby, and your clock you can reach tend to minus 223, actually I think I made it those estimates, while ago, you can get to the competitive competitive numbers of what people 11:29:10 are doing with torsion balance and so on. And and I know that's a big dream, continue to be a problem that bothers us right because the gravitational interactions still week. 11:29:21 And that's why that's a long number, the precision of measurement metrology has not made advanced for a long time. 11:29:29 Thank you. 11:29:33 There is a question about I would like to know about what is the limiting factor for the newest regime clock in JIRA to reach 10 to the minus 20. 11:29:51 What is the limiting factor. So for measurement precision I think we are there, we will be able to report these numbers in the coming month for the systematic uncertainties, we of course need to to characterize, and the remaining thing is rated attempted 11:29:58 a PBR that we need to characterize the black body radiation. By now we actually sort of a thermometer now that's that. It's a specialty extended, we can actually see how homogeneous of the system is and and so on. 11:30:12 At the moment we actually took an approach of spatially control every single part of the vessel of the vacuum chamber, so that we are trying to make it a homogeneous Lee thermal thermal environment as homogeneous as possible. 11:30:32 Our goal is to have to show the accuracy at the level of Latinos 19. 11:30:36 For this call. 11:30:37 But in principle, in principle, June dipole dipole interactions and code lucky, their actions and all of the in canister that's very exciting. 11:30:46 That's an excellent question. And in fact, the dipole dipole interaction because we made the sample relatively dilute, and this is the one of the two approaches the 3d lattice will continue to explore dipole interaction with you. 11:30:57 But in the one D system because the system, you know, we're basically relying on building a really large system. 11:31:03 But the density is low in comparison to the 3d optical artist clock. So the Doppler effect is likely to be very small. The effect you were talking about that we earlier when we were talking with Mariana about spin orbital coupling. 11:31:18 You know when we did that work together, a few years ago when the loudest is horizontal, you can actually look at an ESOP way of interactions of animal for me also tunneling back and forth. 11:31:29 And here you will see that effect as well. This is actually part of Jake's question earlier about what's so interesting about, you know, redshift, but you will actually have to study there's a spin off with a couple of things with the redshift in in mind 11:31:43 that I think is really interesting because I would love to have a systematic effect of that order to be limiting us, but at the moment I think that we are going for low density. 11:31:53 So, so I showed a map where density shift per count is being measured out just by looking at the entire map out of the CCTV camera and ended that density the fact that we are pretty certain we can characterize below tenements 19 level 11:32:11 date in. Excellent. Is there any more questions. 11:32:19 In, an open, you're raising your hand and debt. 11:32:24 Go ahead. 11:32:25 Thanks. Thank you very much. So yes so john very nice talk I really enjoyed David and James both. So, I'm just to answer your last question so I was just wondering that since you could take john you mentioned that you can create a superposition with the 11:32:40 clock. 11:32:42 And if these clocks have certain masses and if you can put them very close. Perhaps one can measure the, even the nutrients constant, of course the problem will be that, you know, the gravity gradient noise because you know this is always present. 11:32:58 So maybe when we'll have to drop it in a drop tower or something, you know, maybe on Earth, one can do it. Maybe in grand central authority or maybe in Fermilab if I just go underground, where because I can get rid of the seismic noise and things like 11:33:11 that maybe there's possibility when can perhaps trying this kind of experiments. 11:33:18 But thanks for asking that I think putting the two atoms together, the mass is just too tiny, too. 11:33:24 So the only way to do it is one of the partners got to be massive. 11:33:28 Exactly. I mean, not that not be the atoms you need some massive part yeah yeah and so you can, you know, people actually. 11:33:35 parameters that you can actually measure correct victory. And there again is using earth as your experimental field on that entire earth and mass is providing the gravitational potential, and you can actually looking at it this interference of Adam interferometer 11:33:58 to allow you to constrain or measure, actually, in fact victory, but again there are lots of a systematic This is the one new approach on victory. 11:34:09 And there are some disagreement was, was the existing Kemal classical torsion parents or other techniques that that's out there, we'll see if the elemental formula will continue to advance the state of the art for clocks I think it's very challenging. 11:34:30 time. It just along that point so one member from my talk I discussed this file structure constant for gravity. 11:34:37 So the idea that we can use the sort of quantum related measurement techniques for measuring big G is is really challenging because the equivalent thing we did with electromagnetism, really relied on the structure constantly being so small. 11:34:53 So when we talk about systematics what we're saying is we have to have some really large mass, and we have to know it's where what the message is so inertial value, which we can do, but also we need to know its density and distribution. 11:35:06 And that's turned out to be a huge systematic that we don't have great way to solve. 11:35:09 So, we can solve that, then the other techniques really start to go and become important but without that very prosaic. Where's the stuff inside the sphere. 11:35:19 It turns out that it's really hard to get those next levels of you, I absolutely agree with you there. But in principle, I'm talking about technology let's say from 30 years from now 50 years from now, maybe I can think about take a diamond in bed Yeah, 11:35:32 either BM which is June was talking about which has a covenant lifetime very long. I can map it to nuclear Spain make it even longer minutes, perhaps, and then maybe I can do this kind of experiment, of course, having said so. 11:35:47 We have 42 orders of magnitude to be. 11:35:50 So good luck. 11:35:53 Have to dream big. Of course it's extremely extremely hard problem so you have to really push on, but it is a possibility and this is what I'm saying. 11:36:01 Actually, so Jake, if we can, if you can get the clock to 10 minutes 24, and I remember those estimates, and you have Asmir, I think that's the heaviest element that we can get our hands on it, make it as easy, medium, that's a meter, and they'll sphere 11:36:14 and make it appear like a Jake said it's actually really important human. That's why PTV invested so much on spherical fear of silicon, they really need to know what you know the crystal, where the masses distributed. 11:36:29 If you can make awesome em sphere and you your clock, and you move in and out of 10 of us 24 you will be able to see it, you'll see great gravitational G, but again you know if I barely seen it, to actually make a very high precision measurement. 11:36:45 It's, it's not going to be competitive yet in the next 20 years I think 11:36:55 the gravitational things just them we could right. 11:37:01 I thought I saw 100 from dead, but I don't know if any more that you have a question or you want to do in terms of the on the limit the clock comparison limits on time variation of constants in you know commensurate commensurate clocks and different elements. 11:37:23 I'm just wondering, have people looked at, is it possible to look for variations with motion of the earth, or the diurnal variations. 11:37:34 I mean I guess you would need enough stability and enough data collection to have a significant meaningful search for signals at a certain period is city but I just wonder if that's even know. 11:37:46 Is that possible now or when might it be possible 11:37:51 to 11:37:53 comment on that so that that is possible now that's one of the kinds of measurements that we've been able to do with clocks and, you know, the thing that makes that doable with clocks is that we have such good understanding and control of systematic effects 11:38:12 that we can be confident that over the span of, you know, days, weeks, months and years, that there aren't there unwanted noise terms, showing up in the clock frequency so we can look for these fundamental effects like you're talking about, as the Earth 11:38:30 rotates or as the Earth moves around the sun. 11:38:36 And that's been used for tests of, you know, local position and variants and I also showed a slide where they don't know competitive. In fact, leading constraints on rents and variants using Glocks. 11:38:57 Go ahead money I do have a comment on that or I just have a comment so this will Terbium plus paper that was six months in beta. 11:39:07 So for the Lawrence and various variations, there is no reason why it cannot be done more and they actually have their frequent measurements for comparing tutorial plus clocks. 11:39:17 So that was specifically tolerance and variance, look for is a daily variation and also for the variation was going around with the song, to be able to get. 11:39:32 She coefficients Lawrence relatively efficient. So that's exactly what type of experiments, which you're asking about. 11:39:41 Okay, I also add a comment, quick comment. I was actually share a slide that Mariana actually showed this wasn't what Dave was saying that you know you have these clocks you can build a network, you can actually look for keep a record for a long time. 11:39:42 Thank you. 11:39:57 This was a measurement record that was long time ago, back in, 2005, the first data point is actually the first strontium clock measurement we made each other that. 11:40:08 And you can see there's a sort of across three different continents Europe, Asia and in the US, North America. We kept the clock comparison for over two years. 11:40:18 And so there's two sides real period as Earth is among around the sun. The problem is the time is the only way we can compare is through the GPS, because these clocks are located very far. 11:40:30 And the only way we can connect is through cesium because that's a common, common infrastructure. To this day Saturday, we still do not have intercontinental connections optical clock so what Dave talks about the boulder area network is all within border, 11:40:44 and Europe has a European network. 11:40:49 Hopefully soon we know, putting, that's another high urgency, putting satellites, is where we can actually connect these different continents and making these type of comparisons at $10 18 and beyond level. 11:41:07 Excellent.