10:00:22 Alright welcome everybody to the second part of this morning session, I will wait one more minute to allow people to rejoin, em, would have to experimental talks, and also where this discussion breaks.
10:00:42 A or not break but the discussion session in the middle.
10:02:06 Alright, so let me start the session now it's my pleasure to introduce our next speakers David Hume. He's a workout nice a on the, the iron storage group, and he's going to tell us about quantum metrology, and test of fundamental physics, with drop iTunes,
10:02:25 Dave, thank you very much for speaking today.
10:02:29 Yeah, thanks a lot. Anna Maria, thanks to the organizers for this opportunity.
10:02:35 I really appreciate the format of this workshop where you've given a whole lot of time for discussion so I'm looking forward to more that today and in the next couple of days.
10:02:49 So what I'm going to be talking about really falls along real well with what we just heard from Marianna, which is optical clock measurements for testing fundamental physics.
10:03:03 She did a great introduction to the kinds of fundamental physics and experimental systems that we work with.
10:03:10 So I won't have to spend as much time on a lot of that but I'll focus in on some of the experimental techniques that we use with trapped ions in particular, and hopefully give you an idea of the state of the field and where we're going in the coming years.
10:03:34 So here's an outline I want to just give an introduction to precision measurements with trapped ions. Here I'm really talking about clock type measurements and the kinds of tests the fundamental physics that have been done recently with those systems,
10:03:50 and then I want to spend some time discussing, you know how we're, we're trying to extend the reach of these chap Dion measurements, both in terms of the kinds of atomic systems that are accessible for these measurements, as well as the stability and
10:04:08 the accuracy that were able to achieve with them.
10:04:12 So we'll talk about some recent work related to both quantum logic spectroscopy which is a key technique for enabling measurements on otherwise inaccessible systems, and the work that we've done to improve measurements stability.
10:04:30 So I'll start out just giving you an introduction you know this idea goes back many years now to sort of the vision of Han's day mount. And as he described it for trapped on systems, it's a single atomic particle forever floating at rest and free space
10:04:47 and if you, you know, go back to those papers he would actually turn that into an acronym which is barely pronounceable, but it's a really nice.
10:04:58 You know ideal that we continue to work with and what it's pointing to is several things. One of them is quantum limited experiments so we're really working with a single or individual trapped particles.
10:05:15 Forever floating we can achieve very long interaction times. In fact, in some cases, a single eye on the self same ion can be stored for months at a time.
10:05:25 We can use laser cooling to bring these ions all the way to the ground state of motion which, in the context of optical clocks means very small relativistic shifts, which is important for systematic uncertainty and free space.
10:05:42 That's an idealization but it points to the fact that we have really good control of the environment. so we can achieve very small perturbations from electromagnetic fields.
10:05:55 So, you know, this is a really nice vision and we've been working towards this for a long time. And I'll just say, a long time ago this is going back to the 1980s, the resolution that day males predicted for these kinds of clocks was at the level of 10
10:06:15 to the minus 18. And, you know, just in recent years we've been able to achieve that level of systematic uncertainty, and that level of measurement uncertainty as well.
10:06:28 More recently there been of course a whole lot of developments and, you know, developing the toolkit that enables us to do this but one thing I want to point out in particular, the ideas coming from Dave Weiland and his work over many years in the eye
10:07:04 storage group. We can now also implement very strong and controllable interactions between ions, and that allows for some of the experiments I'll describe it allows for generating entangled states between ions so it's just a really interesting addition
10:07:04 to this toolbox that's become very important.
10:07:09 So, Marianna has already shown a really similar slide to this so I can kind of skip over it, but the basic idea is that we're locking a laser to an internal resonance in an atom, you know here it's shown as an STP transition, where it's the electron that
10:07:28 serves as your very stable oscillator. In the atomic system.
10:07:33 Man, we have some tools that allow us to first lock the laser to the atom and then count the laser frequency which in our case is all the way up at about a pet a hertz that attended the 15 hertz, and that needs to be divided down without losing any of
10:07:51 the precision, which is done using a 10th of a second. Laser comm something that was invented through the work of Ted Hanson Jan Hall, and was awarded the Nobel Prize in 2005 so there's been a lot of interesting
10:08:11 tools that have been developed that are making this possible
10:08:17 we characterize the performance of clocks generally using two performance characteristics. One of them is the accuracy that's the offset frequency of the clock from its ideal unperturbed resonance frequency and the other is the stability so that has to
10:08:35 do with the statistical fluctuations in the clock frequency as measured, so its accuracy, it has to do with things like field shifts if you have a magnetic field, it can shift the frequency of the clock and lead to a systematic effects so we spent a lot
10:08:53 of time characterizing that kind of thing and trying to control it and minimize it as much as possible.
10:09:01 And then the stability.
10:09:04 In general we think about the projection noise limit, which has to do with the number of atoms that you have in the clock and that just leads to a fundamental limit in the noise that you get when you make measurements on the clock state it enters into
10:09:23 the stability here as the signal to noise ratio. So it's better with higher numbers of atoms and there are quantum tricks that we can play, which I won't be talking much about in this talk, but it's an you know really interesting avenue of research that
10:09:41 has been pursued by a lot of groups in general for the measurements that I'm going to be describing in this talk, at least on the ion side we have a single ion so the signal to noise ratio there is just one
10:09:57 there, like I've said there have been a whole lot of developments in this field over the years I want to summarize that here. We've already seen plot like this, but optical clocks have now overtaken their microwave predecessors in terms of both accuracy
10:10:15 and stability so we have 100 times more accurate clocks now based on optical transitions, then the standard for time in the world which is the cesium.
10:10:30 I refine resonance.
10:10:32 They've also for many years now approached quantum limits and precision. So that's opened up opportunities for using new quantum techniques or enhancing that precision.
10:10:46 These measurements have now been applied to a vast array of atomic species, I'll spend some time talking about this.
10:10:52 I put up the periodic table it gives you an idea of the kind of breadth of possibilities and there are out there but I have to add that there are also we're beginning to do measurements like this on molecular systems which are much more complicated level
10:11:09 structures, but some of the techniques that we've developed can now be applied there. And in addition to things like you more exotic exotic systems like highly charged ions so imagine you know taking off, many electrons from any of these items on the
10:11:26 periodic table, there's just a huge range of possibilities and interesting measurements that can be done with all of these Adam, you know atomic and I onyx systems, accessible.
10:11:43 These measurements are starting to extend across continental distances, notably in Europe they built a big network, connecting metrology institutes and other institutions with ultra stable optical fiber, links, so it's starting to the you know the size
10:12:00 of the networks are starting to spread. And as we've discussed already, we're thinking about ways to make this bigger and even going to satellite based systems.
10:12:11 And finally the subject of this workshop is that these measurements have found numerous new applications and fundamental and Applied Physics, as evidenced by this review paper from Marianna and company from a few years ago.
10:12:28 So there's just a whole lot going on, and hopefully I'll touch on some of that here so I want to start to, you know, mention some of the tests of fundamental physics that have already been done using these clocks.
10:12:42 The basic tool that we have is we can look for space time variation in the clock frequencies. So we're comparing the resonance frequency and one atom to the resonance frequency and another atom using this femtosecond calm, or measuring a ratio which is
10:13:00 not limited and its accuracy to the accuracy of the primary standards.
10:13:08 Man, you can ask the question, well what my calls these clock frequencies to vary. One thing is if the fundamental constants are not truly constant, then you can see a drift in these ratios, in particular the fine structure constant sets the scale for
10:13:26 the energy level differences in Adams and you can search for drift and the fine structure constant.
10:13:34 using atomic clock measurements.
10:13:38 Violations of relativity theory so if you have two clocks and different reference frames you can test the prediction of relativity, and look for.
10:13:53 Look for deviations from those predictions to test some of these fundamental principles like level position in various or Lorenz and variants.
10:14:03 And last week coupling to exotic particles or fields. This is something that Marianna has already talked quite a bit about and I'll mention a little bit more about but clocks are really well suited for looking for these ultra light, dark matter candidates
10:14:19 with masses in this range, well below an EV where they could lead to slow oscillations in the clock frequency.
10:14:30 So just to give you an example. This has been quite a while but quite a while ago, but we made a measurement over the course of about a year between the aluminum ion optical clock and the mercury ion optical clock at NIST, and we saw that that ratio stayed
10:14:52 constant, to the level of about eight times 10 to the minus 17 that's the one sigma uncertainty there over the course of the year and by taking into account the sensitivity of these two resonance frequencies to change in the final structure constant,
10:15:03 we could use that to put a really stringent bound on the linear drift, and the fine structure constant alpha, which is that the level of about two parts intend to the 17, per year.
10:15:16 So we've done very recently, some more measurements of all of the optical clocks at NIST and comparing them to jail so this was a big effort, involving a bunch of different groups, the, you know, in storage group, we have the aluminum ion clock, there's
10:15:36 the group of Andrew Ludlow at NIST that has the Terbium lattice clock and the group of Junichi Agila that has strontium optical lattice clocks.
10:15:48 So, three clock groups working together in conjunction with groups that are focused on making stable optical links between these institutions, so we had the group of Nate Newberry who constructed for this measurement of free space optical link, connecting
10:16:08 between the one of the towers on sees campus to the penthouse over hedonist, and then the comb groups. So, Scott diddums and Tara 14 a leading the measurement groups that just, you know, make these really precise measurements possible so it's a lot of
10:16:31 people working together, together to make this happen.
10:16:35 This is kind of typical data from a day of measurement where we've characterized the stability of these measurements, or the three possible ratios so we have you Terbium strontium and aluminum, all three possible ratios between them.
10:16:53 Starting at four the aluminum clocks about one times 10 to the minus 15 stability at one second averaging down as one over root towel. And then for the lattice blocks with higher stability, averaging down faster all the way into the range of 10 to the
10:17:14 minus 18 in less than a day. And one thing to note here is that all of the instabilities associated with the network. So, these fiber optic links the free space links the cone measurements are all well below the instabilities of the clocks themselves.
10:17:30 So, the, the precision of these measurements, is really given by the clocks, we made measurements like this over the course of several days in fact starting in
10:17:44 November of. The This was 2017 and extending through June of 2018 made a bunch of measurements that are really consistent over that time and the main output of this or one of the primary outputs of this are three numbers that are now the best known constants
10:18:03 of nature of, you know, these optical clock frequencies, we can write them down to 18 digits, and the uncertainties here correspond to total uncertainty from both systematic and statistical effects that are in the mid tend to the minus 18 range.
10:18:25 So that's something that was just published this year. And it's a really nice thing that we can use that exact same data to look for possible signatures of ultra light, dark matter so this is something I don't need to spend too much time on because Marianna
10:18:42 has already discussed this but the basic idea is that we take that data over time and we search for oscillations and the frequency ratio, that would show up at the competent frequency corresponding to the mass of the dark matter particle, and for the
10:18:59 clock measurements those frequencies tend to be in the 10 to the minus 22, up, up to 10 to the minus 17 or so easy.
10:19:09 it has which would appear as a, you know, an apparent oscillation in the fine structure constant, in this case, and there's an atom dependent sensitivity that comes in there and that's something he wanted that to pop up.
10:19:37 That's something that's really important for making these measurements and it varies from Adam to Adam so among all the measurements that I've discussed so far the mercury ion has the most sensitive sensitive transition because of relativistic effects
10:19:52 in its structure. It's about 10 times more sensitive than the next most sensitive which is the Terbium lattice clock. And, you know, despite that, much greater sensitivity improvements that we've made and measurements stability.
10:20:09 Over the last 10 years have meant that they provide competitive constraints on this dark matter coupling constant over a range of masters and you know Here I'm showing an exclusion plot for previous measurements that have been directed at this including
10:20:27 measurements on atomic disproves em and Dema boosters group and measurements between two microwave clocks at the seared group and then Adam cavity measurements that June is going to discuss more.
10:20:43 and the next talk.
10:20:45 But all of these together, combined to make close to an order of magnitude improvement over those previous measurements over several orders of magnitude in mass.
10:20:57 So, that was published, just recently with those ratio measurements.
10:21:04 So that's, you know, a couple of examples of the kinds of things that we can constrain with this clock measurements.
10:21:12 I should say that the lower end of this, this mass is disfavored by astrophysical observations because you're getting all the way to the range where the wwa wavelength is the size of observed galaxies.
10:21:28 So that's an interesting astrophysical constraint that shows up right in the same range that we're beginning to constrain here.
10:21:38 And I just want to mention I had nothing to do with this measurement but to give you another example of the kind of measurements that have been done with ion clocks to constrain fundamental physics, this is a beautiful results from group at PTB that work
10:21:54 with single the ionized you Terbium, so there they have an S to F transition an optical transition, where they take advantage of this highly and isotopic nature of the F excited state, and by orienting the magnetic field between two clocks differently
10:22:16 and relying on the change in orientation as the Earth rotates and revolves around the sun. They can do a Lawrence symmetry test that was actually much more stringent and particular in the electron sector than what had been done previously.
10:22:39 So they show this really nice stability plot averaging down all the way to a million seconds, and they essentially see no evidence of excess oscillation.
10:22:54 In that signal in the range of frequencies that they looked at.
10:22:59 So that's just another example.
10:23:02 I think that, you know, the Terbium system is particularly interesting for this because it has this highly and isotopic excited state.
10:23:15 Okay, so that gives some flavor of the kind of measurements that we're interested in making and I want to talk about extending the reach of these trapped ion measurements and a really key tool in this is quantum logic spectroscopy which has been, you
10:23:36 you know, engine behind the aluminum ion clock and is now getting applied to other systems. So just real briefly how that works. To begin with, if you trap to ions in the same trap, because they're tightly bound together via cool repulsion.
10:23:53 If you call one of those ions you will call sympathetically, the other eye on so we immediately have the ability to call any ion from, you know, the periodic table, down to the ground state of motion, within some constraints, and the basic idea for doing
10:24:11 state detection is that because we can make these ions interact we can do a quantum gate between them, and they're there you're transferring information from the spectroscopy system to the qubit system, where you can then do measurements on it.
10:24:28 And the thing that you're overcoming here is that very few atomic systems actually have a really nice cycling transition that can be used to do fluorescence measurements.
10:24:40 So in the absence of that you have to do something different from you know the way that all of the species have been detected before.
10:24:48 The trick here is just to do a gate between the two ion species and then detect on the qubit that you've stored with, with that ion. This relies on cooling to the ground state and a couple of sideman pulses so I'll describe that process real briefly.
10:25:05 The first step is going to the emotional ground state using the qubit, and you can apply a side band pulse here on the aluminum ion system, which excites one quantum of motion dependent on the clock state of aluminum.
10:25:19 So you're trying to distinguish whether the ion is in the ground state or the excited state, you do a sideman pulse on this auxiliary transition, which inserts a quantum of motion only if the ion is in this state, you transfer that motion to the qubit
10:25:41 by doing another sideman pulse on the qubit state.
10:25:41 And there you transferred the initial superposition of the clock state and aluminum to the qubit, and then you can detect it using fluorescence measurements.
10:25:50 So this is an example from the aluminum system where we get a certain number of photon counts when it's in the ground state. And then, larger number of proton counts when the aluminum ion is in the excited state, really nice thing about this is that it's
10:26:06 so called quantum non demolition or a projected measurement.
10:26:11 So that means you can repeat the measurement many times get high fidelity, and it can also serve as state preparation. So, another necessary ingredient in doing precision spectroscopy on a atomic system is that you have to prepare the state.
10:26:27 So, this is one way that you can do it if you have this projected measurement, as I've described.
10:26:33 So, since this was first demonstrated on aluminum it's been applied to several different atomic systems. Here's an example showing Quantum Jumps between several different Zeman sub levels in the ground state of aluminum, and you know the trick here was
10:26:53 that you have to transfer the information without scattering a single photon from the aluminum state, because that would,
10:27:03 it would destroy the initial state that the aluminum was in so this was done a bit differently from what I just described, but nevertheless you can see that it's a projected measurement with Quantum Jumps between several different levels.
10:27:18 It's now been applied to highly charged ions and the group peach MIT.
10:27:24 doing measurements on argon 13 Plus, and also in our group and pizza group. There have been experiments on molecular ions. So here you have a much more complicated atomic structure where you have, in addition to the electronic degrees of freedom and spend
10:27:45 degrees of freedom you have rotational and vibrational degrees of freedom, but using those features that I described before, that the measurement is a project of, you know, preparation of the state, very precise measurements have been made now on molecular
10:28:07 ion systems as well.
10:28:10 So with this, you know, spreading to so many atomic systems, I guess, I wanted to just put up this, this vision that I think a lot of people in our community have in some form or another and Marianna has already mentioned, I think it's really appropriate
10:28:29 in this workshop to think about what can we do with this vast network of clocks, making measurements at the level of 10 to the minus 1810 to the minus 19, who knows how hard that will go.
10:28:46 You know all connected via stabilized links.
10:28:51 So I just want to put that up there maybe is food for thought. I think it's a really attractive.
10:28:59 Possibility it's something we're working towards. I think it has really broad science reach you can do the kinds of measurements that I've discussed some already there are opportunities for testing QED on very simple atomic systems.
10:29:13 There might be applications and gravitational waves if you have satellite based clocks.
10:29:19 It's a modular and it's an extensible thing you're not really putting all your eggs in one basket, you know you can hook your latest favorite ion or add them up to this network, and it will just enable more and more precise measurements.
10:29:36 So, just something to think about there.
10:29:40 So now I want to move on to
10:29:44 some more discussion of quantum logic spectroscopy but as it pertains to improving measurement stability, and maybe I should just ask, How much time do I have remaining now.
10:29:59 Sorry I muted.
10:30:01 The most five minutes at the most five minutes okay well this is going to have to be pretty quick. But I was going a little slow. So there are a limited number of things that you can do to improve measurements stability.
10:30:14 If you're at the projection noise limit. First thing I want to talk about is increasing the item number.
10:30:22 And this has to do with quantum logic spectroscopy because for aluminum, in order to increase the atom number we're going to have to come up with new techniques to make measurements, like what I described but on larger strings of ions, and it's not going
10:30:37 to be just applying the exact same whole sequence to longer string of ions we're going to have to adopt new, new gate schemes and probably you know borrowing from the work that's been done in quantum computing and ion traps so the, the idea is to go from
10:30:56 here to here, and then in the future you can imagine doing something that's a much larger scale.
10:31:05 The thing that we've implemented recently is shooting your cat interferometer, which is a really sensitive detection of ion emotional displacement and I'll just describe basically how this works.
10:31:18 So imagine a cubit, this is a face space picture of the motion, you start this interferometer by doing a pie have a pulse on the qubit state.
10:31:30 If you then apply a state dependent displacement you've separated and face space there's two qubit states, and a different emotional wave packets.
10:31:40 And you use that to sense some unknown displacement. So now the state, you've added this unknown displacement beta.
10:31:52 If you then recombine the emotional wave packets. you can interfere them by doing another, I have a pulse on the qubit and detecting and the or probability of detecting the ion in the ground state has something to do with this geometric phase that you've
10:32:09 built up during this interferometer. So this is just another way of getting, you know, a motion sensitive qubit measurement in a trap die on.
10:32:27 So this has been applied to a number of different things over the years it was first demonstrated in our group just showing this so called Schrodinger cat superposition state of the atom, and using it to study emotional coherence, it's the same idea has
10:32:46 been used for detecting single atom. Sorry single photon recoils.
10:32:49 And it's been applied to very sensitive force detection in ion crystals, up to hundreds of ions in a pending trap. And this is really the idea that inspired this work that we've done now trying to scale up quantum logic spectroscopy, this is a case where
10:33:09 the ideas clearly scalable.
10:33:12 So what we do is that exact procedure where we put as the unknown displacement, some state dependent force on the aluminum ion. So here I'm showing the level structure again, the qubit and then eliminate my on it has single listeria and a triple p one
10:33:32 state. And what we've been able to do by inserting this state dependent displacement on the aluminum ion been able to see nice resonances with single magnesium and a single aluminum, and we've scaled that up to seeing resonance and residences and up to
10:33:51 three aluminum ions, and in this case it wasn't even a linear array of ions here the ions had started going to go into a zigzag configuration.
10:34:06 So this is nice. It seems like it's a pretty robust technique.
10:34:09 We've looked at the detection efficiency and now we're using this interaction to detect the clock state of aluminum.
10:34:17 One interesting thing that we found here is that it's actually more efficient. To do this detection at the Doppler limit, then using ions called to the ground state and that's just because the extra ground state cooling takes some time.
10:34:34 So, we found that it's more efficient at the Doppler limit, and as you put more detection ions in there so scaling up the number of detection ions are cubits, we get better to signal to noise ratio which is represented in this detection efficiency.
10:34:54 We've looked a little bit about how this scales in terms of reaching the projection noise limits and the overall message is just that it looks pretty good even with a single detection sequence, although you will have projection noise from both the spectroscopy
10:35:10 ions and the logic ions in a single detection sequence, you can get very close to the projection noise limit. And if you repeat it, like we do in a single experiment you can really saturate this.
10:35:24 This standard quantum limit.
10:35:28 And I think that I'm really running out of time here so I want to go quickly over this. We've done some work as well, to improve the measurements stability by not implementing a more stable laser to improve this first factor which is the quality factor
10:35:48 of the residents were probing, but using a new technique to mitigate laser noise entirely.
10:35:54 And the idea there is just that, if you have correlated.
10:35:59 Laser noise on the two systems so you're probing them with the same laser.
10:36:04 If you do your measurement right, you can still get frequency dependent signal it's dependent on the frequency difference between your two clock ions and different traps here, because in this superposition there is some component that's a D coherence
10:36:25 free subspace. So any common noise, just drops out.
10:36:30 And there we were actually able to see the lifetime limit instability.
10:36:36 For the two aluminum clocks in the low sort of 10 to the minus 16 level that's about a factor of 10 improvement over what I showed earlier in the ratio measurements that we did, that's now actually been applied to measurements between an aluminum ion
10:36:54 clock and the Terbium lattice clock, a slightly different, as soon as possible. Sorry.
10:37:00 Yeah. And with that, We've. This can be for discussion.
10:37:07 And I want to thank you for your attention, thank my group for all the work and the agencies that funded us, so thank you.
10:37:17 Thank you for the very nice dog so we have some time for for discussion same, please raise your hand or or speak up and mute yourself.
10:37:34 Maybe then I can you start asking so in John's experiment when we were trying to do the with the analog have to cut the state. We were really sensitive to center of massive to actions, and this was kind of the most important limitation for us, internal
10:37:50 setup is this also something that matters or, or, or it's less important.
10:37:56 Yeah it does matter.
10:37:58 And, you know, one difference between at least the early work that john was doing, is that we're right on resonance. Yes we are.
10:38:09 Yeah, yeah, which is which means that those fluctuations in the center of mass frequency show up more strongly.
10:38:18 So what we actually did to mitigate that was to lock in in interleaved experiments on the ion we would lock in that frequency by adjusting the trap voltages in real time.
10:38:32 And so that over the course of, you know, hours of measurement that would keep the center of mass frequency right where we had calibrated.
10:38:43 Nice great things. So, I see another an open Please go ahead.
10:38:51 First of all, David very nice talk, I just wanted to ask you, so you're very nice that you were using this rare earth materials Terbium. And so, what is the conference timescale Can you get it for these systems now.
10:39:06 So I'll just say the Terbium, and I'm not sure if you're talking about the Terbium ion, or you Terbium lattice.
10:39:13 For the which one you were using. Perhaps you were using in I guess. OK, so the measurements that we made yeah there was a Terbium lattice clock involved in those and that's that's in the group of Andrew Ludlow at NIST that the ultimate coherence time
10:39:30 limit in all of these clocks is given by the excited state lifetime.
10:39:35 And with the Terbium lightest clock that's on the order of 20 seconds, I don't know the exact number, it's real similar to what it is with aluminum, which is around 20 seconds.
10:39:46 So if you want to do better than that.
10:39:49 You're going to have to choose another Adam.
10:40:02 And there are certainly possibilities out there for example the strontium transition has a longer lifetime, the excited state has a longer lifetime. More than 100 seconds, and the Terbium ion which I also mentioned has essentially an infinite lifetime.
10:40:11 I don't know exactly the number but its measured in days or months or maybe even years.
10:40:21 Thank you very much. Thanks.
10:40:23 Lance, go ahead. Yeah, thanks for a great talk is fascinating, um, speaking of other systems, Miranda mentioned the thorium meta stable nuclear transition Could you say a word about the different technology that's needed to do clocks like that versus
10:40:39 the ones that you do.
10:40:41 Yeah, so we actually do in our group have just just starting up an effort at thorium ion clock.
10:40:52 So the first thing is that well for various reasons.
10:41:03 Thorium three plus, is an attractive, a candidate for using as the nuclear clock, because it has a nice structure for for laser cooling. Basically, I mean the nucleus itself doesn't care so much about exactly which is nice species you use, but you have
10:41:20 get a hold of it somehow. And so, the thorium three plus is, you know, single electron, Adam it's a simpler system. So there's the challenge in generating for him three plus and loading it into the ion trap.
10:41:38 There's a challenge in holding onto it long enough because it will undergo charge exchange collisions with background gas more readily in the single he is Adams, so it's going to be in our case, cryogenic system.
10:41:56 And then, you know, there's probably the biggest challenge in all of this is generating highly stable laser light at 150 nanometers, which is something we're going to rely on June's group, and their expertise and making.
10:42:17 You know, high harmonic cones, that can reach that wavelength So, June might have more to say about that. But there are really a number of challenges that you know they need parties have not just our group but other groups in the area.
10:42:34 Thanks a lot.
10:42:38 Great. And so we have three more minutes in, Diego you want good you have a char questions. Let's go for it. Otherwise, ABC do things long we can postpone it to the, to the discussion in linear.
10:42:53 Well it's Personally, I have to meet the discussion because I have other obligations. So just make a suggestion that there are other ways to use atomic clocks are this precise systems to the tech dark matter for is that we have a paper with Peter was.
10:43:11 We saw a leader in Europe on this. And the idea is that by discovering of the matter with your state's. You may, you may use on them, a new face, that maybe also you know i characteristic of the interactions that are happening the clock.
10:43:28 So for instance, the same that you have when you have a club you try to get rid of all the possible backgrounds that are hitting your stage.
10:43:39 Some of them. I mean, once you get to the Muslim backgrounds, you may still have that amateur background, which is generating some, some noise because of a scattering with the clock, not because it is coherently associating with it.
10:43:52 But really, because it's picking your your your atoms of the time.
10:43:56 And I said, unfortunately have to miss the discussion.
10:43:59 So, maybe tomorrow can join for this. Yes we can continue, we can continue the tomorrow and there is going to be your storage room, that's a three day workshop.
10:44:17 Great, go yeah that sounds interesting if I can just ask quickly that model of dark matter It sounds like it's heavier mass. It's like classical classical particles keeping keeping your your your atoms so I mean so many times that eventually they they
10:44:31 may have been, I mean they have may have an effect. Thank you very much. Okay, we can't get.
10:44:35 Thank you for the comment. Great. So, let me say that we sang the for the fantastic talk, and then we go to our next speaker, that is john g from Gila.