08:00:35 So, thanks everyone for coming. It's been two days of exciting talks and discussions.
08:00:43 Today's our last day and the talks will be centered around gravity, although there will also be talks about interferometry and mo methods.
08:00:55 And our first speaker.
08:00:58 Let's first speaker will be Harmut Grote, who will tell us about quantum enhanced interferometry for new physics.
08:01:08 So please take it away.
08:01:13 Hard.
08:01:24 Hello everyone.
08:01:26 Yeah, thanks for this interesting conference and for the opportunity to speak. And before I start, I would like to mention that. And for those of you who know the quantum technologies program in the US, we have a similar program in the UK, which was actually
08:01:45 inspired by the US model and so, and I'm talking about the work mostly today but not only have one of these candid consults Yeah.
08:01:58 So, we have been funded for quantum enhance in interferometry for new physics that means for experiments, trying to discover new physics, of course, we are a consortium of five UK universities and international partners.
08:02:16 And just to mention some of the under the consortium funded working for example on the topics that already have been covered like for example of the UK atom interferometer, and in is one of the consultants and an atomic clock network for example.
08:02:35 Okay, so we are working on two themes the nature of dark matter and the nature of space time using interferometry.
08:02:45 And to start with the first team national dark matter which is of course a very large topic. And I found this diagram with which is supposed to be a pie chart.
08:02:56 And that is from the 90s from the cosmologist microphone and so that's his.
08:03:18 time. It seems axioms, and at least in his mind were already a viable candidate, but as history went of course as you know there was a larger focus in experiments on the very promising wimp.
08:03:35 And so our first two experiments we we have all four experiments that we are doing are supporting and the first one is as much for ACCION as possible Dark Matter candidate in the Galactic Halo.
08:03:37 Dark Matter candidate.
08:03:54 So, these are not the axioms that directly would solve the CP problem which, as you know, originally motivated the axioms but if you didn't decouple the coupling constant from the mass then you have an old landscape which is more wellness motivated, but
08:04:16 it.
08:04:18 And there's a range of experiments and searching for these.
08:04:21 And so one of the famous ones for example is a DMX.
08:04:25 And, which is actually looking for the CP Maxi on. And, but we are building a new tabletop experimented such for the actions in the Galactic Halo so if you will.
08:04:40 And the second experiment is a so called light shining in the wall experiment in which you will generate the excellence in the experiments and also detect them there.
08:04:49 This is an interferometry halos called.
08:04:54 So the question is, is only secondary, if you will, it's a new particle search.
08:05:01 And so, ACCION.
08:05:05 Yeah, pretty much behave drastically as a feared because they are masters so low that you have very large occupation numbers and so they are described as appears after year, as we have heard before.
08:05:19 And it was only a few years ago pointed out that in fact, and they induce face difference between the left and right polarized light.
08:05:31 And that does not need an external magnetic field so it relies on the self interaction of the ACCION with, with the light field so whereas MADMX for example as you know uses an extended magnetic fields to convert axioms two photons.
08:05:47 And it's possible to see this polarization retain rotation effect just on a laser beam in the Galactic Halo so the hypothesis of course that the Galactic Halo is composed of ACCION dark matter.
08:06:02 And so this this has further developed in a series of papers. It was originally proposed maybe for implementation in a gravitational wave detector and but now it's realized that it's probably better to do this as a separate experiment.
08:06:19 So, what, what we are building and I've been consulting as a tabletop, which essentially consists of offering cavity so you have a laser that is resonant in this ring cavity.
08:06:33 And then you turn ACCION induced rotation of polarization effectively, you get some side bands and an offset frequency which in a ring frequency which generating cavities and resonate at slightly different frequency, and has a tuning cavity attached to
08:06:50 this way you can couple of the other polarization so the, the signal field and resonant we enhance this as well and so you can tune the whole set up for different ACCION losses and further than sensitivities increased with the application of squeezed
08:07:13 Okay, if you just look at the and read solid graph here this is a possible explanation plot for an hour tabletop set up in the mass range, down to 10 to minus 16, perhaps, he has a DMX comparison.
08:07:31 light.
08:07:32 So, this is solid line is what we potentially can reach, but the technology should be possible to scale up to larger set up so if you scale it up for popular meters.
08:07:45 For example, you could get down here.
08:07:47 And I just, I'm not a theorist but I just learned recently that there are also some new models predicting ACCION like particles, possibly in this mass range which could which could be reached here.
08:08:01 Okay, and our second experiment is a support to allow to experiment so that's the so called light shining football experiment.
08:08:11 So I have mentioned a DMX, which uses this remark of process on the upper right, Feynman diagram here, so you have an axiom field that in the case of our DMX that supposedly a stock meantime that interacts with a setting kinetic field and generates the
08:08:29 But, as I mentioned, you can also try to generate ACCION with the inverse process and detect them in the very same experiment and so you have wall in between and then left and right side of the experiment.
08:08:47 So on the left side here, we have a strong pump demon electromagnetic wave.
08:09:01 Laser wave. Then we have an extended magnetic field. And this generates ACCION travel and optical barrier, which the photons cannot pass, and then reconverted so you do conversion and detection in the same experiment.
08:09:16 That's it. That's electronic football experiment.
08:09:18 They had already been a few of them that have published early results.
08:09:25 what is currently under construction.
08:09:27 And it's dz in Germany and work is the art to experiment. So, and this is a photograph of the installation of the magnets which has just been finished.
08:09:39 So this is to 120 meter beam line so it's really a linear set up folded into one photograph we're looking at the Central and area here which contains this, and one on the left hand side we have the 120 meters string, generating axioms on the right hand
08:09:57 side it.
08:10:00 And we try to detect this and particular what we are focusing, as, as an improvement in in the UK is for example to generate to the to make it better signal for Tony detector.
08:10:15 So, one of the methods to then search for ACCION is to look for individual photons. So, in principle, as I said this right hand side should become completely dark and.
08:10:29 And so you can look for individual photons on the air as, as small as you can get. Background noise.
08:10:39 And so, it is done. One method to do this is with the transition edge sensor at chronic temperatures.
08:10:48 So, he has another sketch of this, what we call the production cavity we have a standing wave 450 kilowatts there. So these optical cavities that that enhance the in going light.
08:11:02 And what is new for this set up is there's also a resonant cavity on the right hand side.
08:11:09 And so the the difficulty of this experiment is really to, to keep the right hand side cavity also on resonance for the axiom fear so on the same optical frequency, on the left as on the left hand side.
08:11:24 So, this is done with some auxiliary laser fields, or this is part of the difficulty.
08:11:35 And, and guys I said this is under construction. Now, and he has some details for those of you who may be familiar with test detector So, and we are working on some innovative, test, test detector was very luck with very low count right and 26 per second.
08:11:59 And we also have some, some ideas, and how to include the second detector on the device as a cosmic cosmic particle beetle, and so on and so, supposedly, we can improve the background noise with, with this test detector.
08:12:22 Okay, and this is the these these blue lines in the exclusion landscape is what apps can reach. And you can compare this to cast for example, which is another type of search for ACCION switch, such as far as the ones that are generated in the sun.
08:12:45 So it's, it's a cube pointed to the sun with a large magnetic fields where then axons from the sun can, can we convert them into photons.
08:12:58 And there are also some ideas, let's say how this could be scaled up so the light shining through all experiment.
08:13:06 And in on the kilometers. So we are now at hundred 20 meters care and, of course, people are thinking about, about kilometer scale.
08:13:18 And, but the the scaling is, it's it's very difficult to to get substantially.
08:13:26 Further, so maybe we need some, some new technologies there as well.
08:13:32 Okay so speaking of kilometer size extensions. I want to make a small x excursion yard side remark on gravitational wave detectors.
08:13:46 And so one of the ideas is indeed that maybe when such innovation gravitational wave detectors come online at some point. These facilities that you know like Google and also maybe CAGR at some point may become obsolete for the detection of gravitational
08:14:04 waves so that's that's really 2030 years down the line.
08:14:08 And, but then these these facilities may be could be used for other fundamental physics and experiments. And so this ACCION search type.
08:14:23 Allah scope might be might be one idea. I just wanted to, to remark.
08:14:26 And because we use interferometry for fundamental physics I wanted to make a remark on the sensitivity of these instruments and already mentioned yesterday the remarkable sensitivity of interferometry so if we, if we compare what what we achieve today
08:14:44 with my cousins interpreter. From the late 1800s.
08:14:51 So here the sensitivity of tend to minus nine relative, roughly, and today we have 14 orders of magnitude more sensitivity, mostly because of some optical enhancements of the basic my cousin schemes.
08:15:10 You can see the basic Microsoft scheme that you know, on the left side in spirit and to end mass.
08:15:16 And in the modern reputation we have detect us. This is enhanced with optical resonators in the arms, and so called power recycling. All of these, you can simply think of just the they increase the laser power and so they, they reduce the quantum noise.
08:15:34 One of the quantum more sources is before don't continue.
08:15:38 sort of squeezed vacuum non classical light to reduce the quantum noise so this is injected from the rear end of the interferometer and lowers the quantum noise.
08:16:05 So there is a remarkable sensitivity today of tend to minus 19 tend to minus 20.
08:16:13 meters which is tend to minus five of the proton size, which of course is only possible by averaging over, and a pretty large area on the surface of a mirror that naturally begs the question, And how can this be used for for the fundamental physics questions.
08:16:37 So, just to point out that soon the Eisenberg's uncertainty limit of these particular grand taskmasters will, will be reached. So, the measurement and it's so precise that in, in, in one moment, and if we take one measurement, the test master sketch,
08:16:56 a kick, which makes the next measurement a bit more precise so there are techniques to to counteract that with so college frequency dependent squeezing.
08:17:10 So of course, you cannot go around the Heisenberg uncertainty, but you can, and modify this squeezed vacuum in a way that you can go below the standard quantum limit.
08:17:24 Okay and another interesting connection is of course between potentially between documented and reputational waves and I found this mind map interesting format on the archive you can see here, there are all sorts of could be all sorts of connections between
08:17:40 gravitational wave and documented documented is of course not the only topic of fundamental physics but, and we can explore what what is already being explored, for example, is read part on the right hand side, so called environmental effects, which come
08:18:00 from Dark Matter around binary binary is binary codes for example which may affect the total murder rate, which may lead to slide waveform defacing and lead phase of inspiring.
08:18:15 And also, which can lead to classy continuous wave.
08:18:29 And I want to point out here another branch, which are the direct, such as for dark matter with Intel from meters and so in this case we use the very sensitive gravitational wave detectors directly as dark metal detector and not mediated by gravitational
08:18:37 If you have by the super radiance effect, black holes in particular this one last one already has been searched for.
08:18:46 waves.
08:18:48 And there's some examples, because there's not so much time I just mentioned, and more detail on but there has been already publications for like a duck photon such, and some other ideas.
08:19:03 We recently have been working on for called scalar field, dark matter for the geo detector. This is a small prototype gravitational wave detector 600 meter long arms.
08:19:16 In Germany, which is particularly suited for the scale of your document as such, because it does not have these activities you see in Lego. And so, the effect is quite simple to understand, as was mentioned in the one of the earlier talks and this kind
08:19:31 of you attack the attack any tool that variation of fundamental constants.
08:19:36 And this happens that the frequency of the scalar field.
08:19:42 And so this this variation of fundamental constants in fact makes all objects objects have fled in in science at this frequency. And so the argument for long time was the gravitation were detected as cancers to first order because the test masses both
08:20:07 get bigger and smaller. In, at the same time and receive cancers, however, that isn't a cemetery in each into from each IDs, if you set up the beam splitter in a certain way.
08:20:20 So in these interpreters the beam splitter is a piece of glass a few centimeters thick, and you have this been splitting surface here. And so as this.
08:20:26 Inspector oscillates in thickness then this reflection surface goes back and forth and this, in effect, makes a net, the differential effect in the interpreter, which you can use to to search for a scale of your dark matter.
08:20:40 So we recently completed such a search with data from the geo 600 detector, and we could set these green shaded new elements so we didn't find any surviving candidate for for dark matter but it's quite interesting that even with this first touch, we can
08:21:01 set some interesting you know upper limits and the others, of course not expected. In the future, especially if you make some small design changes to the gravitational wave detector you can significantly enhance sensitivity.
08:21:19 It's just natural gravitational wave, same time.
08:21:24 Okay. And that brings me back to the last two topics and how we use quantum and and interferometry. And so quantum aspects of space time.
08:21:35 We have two experiments there.
08:21:37 So, we call it experiment three that starts at four quantization Have a nice time.
08:21:45 And another one that look for signs of semi classical gravity.
08:21:51 Okay quantization of space time is pathetic. Of course, maybe most physicists, assume that there is some sort of quantization of face time but of course nobody knows.
08:22:06 And maybe it's what could happen at the Planck scale attend to minus 35 meters, but also that's also not known that.
08:22:15 If so, then there is of course not much chance with current office either technology, and to reach the scalar directly with experiments. However, in combination with the holographic principle.
08:22:31 And this may be possible. So this is quite speculative high risk high gain research and the theory is the under development but the holographic principle.
08:22:44 In a nutshell,
08:22:44 is the statement that you can only put as much information into a volume then fits on its surface.
08:22:52 And so that leads to some reduction of information density. And as a consequence, probably to some correlation or an entanglement between different regions of space time.
08:23:05 In terms of the information content. And so the idea is to practice with into parameters, with two independent into parameters which are closely located.
08:23:13 And then you search for correlated noise between the two interpreters were in standard physics that there should be none.
08:23:24 And it has been one experiment already in the US, which went forward with this idea of hospital for called along to experiment at family lab, which are two co located, 40 meter are affected my cousin interferon meters, and they said a few upper limits
08:23:44 for some configurations, as an instrument description as well.
08:23:49 And so, we are taking this idea forward to two laps can also so this time we are not scaling up, we are making it smaller.
08:23:59 And mostly to be more versatile. So, there are more, even though the formula Tomita has such an interesting upper limits limits the amount geometry is to test so.
08:24:12 And we want to Burt and tabletop into per meter which is more easy to maintain and reconfigure sets that we can also test 3d geometries for example and so in the future, maybe we would bend one of these arms in the middle upwards and and certain combinations
08:24:30 of of geometry that lead to different, or maybe two different predictions of North.
08:24:38 And at the same time, tabletop tabletop setup allows us to be more flexible with the technology as well so we are planning to have a higher sensitivity, though the length is shorter much with some young improved technology as time goes on, so we plan
08:24:59 to have 10 kilowatts and these tabletop interpreters for example, output Martinez, edit that needs very fast data acquisition system and we also have squeezed light with the feminine did not have as a side remark that also is a proposal of using so called
08:25:18 entangled, please state so if you cross the squeezing beams here, and you can have, in principle, some achievement if you look for correlated nice between the two different meters.
08:25:30 However, this relies on extremely low losses so it's not so clear yet.
08:25:37 Officially, but it's and it's an interesting idea to investigate.
08:25:42 So here's our plant sensitivity there's a paper that describes this type of setup.
08:25:50 So the red. Trace here is the displacement sensitivity and meters customer would have achieved by the formula Romita into four meters. Two times two months 18 meters.
08:26:06 Let's go up today from one to 25 megahertz. And so we hope we can be up to 10 times better in this basement sensitivity. With increased power and the use of squeezing.
08:26:20 And, again, here it's interesting to note that if you build very sensitive interferometer, and almost as a byproduct. It can also be again sensitive to these other questions as dark matter so again this will be sensitive at some level to still a few dark
08:26:40 matter. It's a bit less compelling at these higher frequencies but still it will be possible to, to set limits in this in this massive range of up to 200 megahertz.
08:26:52 And at the same time it's also a very high frequency gravitational wave detector. So, the gravitational waves of the Lego, Lego bands above, 10 kilohertz.
08:27:06 However, there is a recent sort of white paper copy of some ideas, and certainly some possible sources from, from the Big Bang, or from audio records and even transients signals maybe in.
08:27:30 In certain multi dimensional theories, so there there are some ideas and so as gravitational waves, proving so so the fundamental physics. It's certainly worthwhile we think also to, in principle to think about how to detect gravitational waves at at
08:27:48 higher frequencies.
08:27:49 So interferometry is not necessarily the best technology to to do this because of the length scaling but it will still be possible to set up elements with this setup as well.
08:28:03 Okay. And you mentioned our fourth experiment. There is an experiment with cryogenic cavities, that tries to find signatures of semi classical gravity for gravity.
08:28:20 And so you can look for self interaction of of the mirrors in a cryogenic activity, and then depending on the theory you'll get a frequency and splitting or not.
08:28:36 And also related to the theme there's a recent a new idea from two of our members of the Consortium
08:28:47 for another tabletop setup so if you were all these, these last two experiments also quantum gravity tabletop setups in a wider sense that, that look at least at some aspect of quantum gravity on quantum space time.
08:29:03 And, and so you the idea is that you bring two masters close together which interact gravitationally, and then instead of trying to detect the entanglement between them.
08:29:16 You look at the effect on the, on this this entanglement has on the light and influence of squeezing of the light.
08:29:25 And so this may make this accessible to a test as well which is described in this quite new paper, and some, some parameters here so it's quite challenging, but not not totally unfeasible so you need 10 million Kelvin, you have to take that 10 ads, very
08:29:43 high q materials, and identity.
08:29:50 Okay, and I'm almost at the end, This is just to mention that.
08:29:54 You also have funding in our consortium to new coating facilities.
08:30:02 So, pretty much all of our experiments rely on a try performance optical coatings, and.
08:30:12 And so, as a new technology. You see, in their position in development which we can make use of in our consortium and of course it. It's also useful for the wider community.
08:30:33 Okay, these are international partners. And that brings me to to a summary, if you will. So, as I pointed out, interferometry has been very nicely perfected for the purpose of detecting gravitational waves.
08:30:49 And we do already found the fundamental physics with gravitational waves not only dark metal but for example the realization that gravitational waves travel pretty much, and as the speed of light came came out of the binary neutron star detections and
08:31:05 several others.
08:31:07 And it's also possible to do direct attack meta searches as I pointed out, with gravitational waves detectors scale up here so talk photons, possibly others.
08:31:20 And that of course we, we can also then more Taylor interferometry to other questions of an amateur physics experiments.
08:31:29 And so, I showed you the example it's often type of ACCION search with and interferometry for Halo scope.
08:31:38 And I explained the light shining football experiment.
08:31:43 And, and then we have this quantization of space time experiment and the semi classical gravity.
08:31:50 Okay, thank you.
08:31:52 Okay, so thank you very much for the very nice talk and we'll open it up for discussion for about 15 minutes.
08:32:05 Any questions from the audience so you can put up your hand and. Let's see.
08:32:07 Yes. So, Tanya Lucy, go ahead.
08:32:11 Hi, thanks for a great tag. I'm so sorry about the ACCION search with the interferometry Hello scope. Can you talk a little bit about what your scan rate might be like,
08:32:21 um, Yeah, I think this these plots are made for something like one, you know, integration.
08:32:31 If I recall correctly. So, I mean, in principle, you use. Ideally you use can, as long as corresponds to the, to the coherence time. So, we expect that the Koreans time is off the order of 10 to minus six of the frequency or the the inverse of that and
08:32:55 so, and yeah there's a kind of a natural time which we integrate but this this compose sensitivity is about a year of work on of magnitude.
08:33:11 And guess. I don't understand that there must be something I'm missing so the reason a VM mixes exclusion is so narrow, is because they just you can't physically change the width and the cavity fast enough so is it just the fact that you're free, like
08:33:26 you're actually on mass is so much lower that you don't need to spend very much time at each cavity link
08:33:36 you and you can also you have much more freedom with this with this couple of couple of cavity, to change the, the resonance frequencies.
08:33:54 Got it. Thanks.
08:33:57 Mariana.
08:34:00 Thank you for a great talk. Can you talk a bit more about the experiments for semi classical graduates I don't understand what specific new physics you're looking for there.
08:34:11 Can you clarify bit more. Yeah, maybe it's more productive, if one of the authors speaks to that, I think, an image, would you would you take this on.
08:34:31 Yes, sure.
08:34:38 An image, we can't heal this one or the next one.
08:34:44 This one, yes I can talk about this one is this one. Mariana, Yep.
08:35:11 sort of semi classical from Newton.
08:35:15 And what the basic sort of fact is that Newtonian gravity depends only on the relative position of the two masses.
08:35:24 So, if you think of the interaction between the masses ENB in the common and differential mode, the effect of the gravity's only in the differential mode.
08:35:36 But that is not true for the Schrodinger Newton type model where the effect of that gravity appears in both in the common and the differential mode so that is basically what we are proposing to detect as a way of either verifying one or rolling out the
08:35:51 other.
08:35:53 Okay, thanks so much.
08:35:59 Um, yeah Can you elaborate a little bit more on that what what is Schrodinger Newton gravity.
08:36:04 Ah, so this is one of these semi classical models of gravity where the matter is to get quantum mechanically but the space time only responds to the average sort of the expectation value of the masses, not in a quantum sense but in the classical sense
08:36:22 that it's the expectation values of those, and effect.
08:36:28 So, basically, in Einstein's equations, on the right hand side you substitute and the expectation value. Yes. what a manager momentum tensor. Yeah. Okay.
08:36:40 Yeah, I mean it. I must point out that this is sort of one of the numerous umpteen candidate, but I
08:36:49 think it is already known that it has other issues like not being referenced in variant and allowing Supra liminal communication and such things.
08:37:05 But I don't know there may be other people who are greater experts are shooting a Newton models than I am.
08:37:13 in the audience me.
08:37:16 some years ago, there was a partially tongue in cheek experiment on by Don page and I think it was a student kilter testing that semi classical Einstein equation and showing that it's not valid.
08:37:36 Is there a conceptual problem with that experiment or does it not test the same thing that you're talking about trying to test here. I think they use the Geiger counter to do two years in the placement of masters and then did the statistics of experiment,
08:37:52 yes look like referring to this other the 1980s page glider experiment. Yes.
08:37:59 Yeah, so that I think.
08:38:01 Yeah, it fell fall for various reasons, one of which was it sort of relied on a specific interpretation of quantum mechanics this many words interpretation and so on and seemed not to be very transparent in other sort of interpretations to quantum mechanics.
08:38:22 So if you go look at the original paper and PRL there were sort of comments to the editor and so on and so forth that sort of argued on this kind of topic.
08:38:32 But I don't know if this specifically addressed shearling a Newton Imus.
08:38:39 Yeah, I mean with the same arguments not apply to, why do they not also apply to this experiment I guess that's the question what's the key difference between this and paging bill.
08:38:55 I don't think they were saying that there was a difference in the common and the different modes of the motion of the masses if I remember correctly.
08:39:10 Okay.
08:39:12 Are Katie, just trying to follow you know this discussion, because I still want to know, was it.
08:39:21 I mean, I imagined that you know this law in some ways, but if it isn't about kind of your slow moving board is where, you know, kind of Newton approximation, as we operate.
08:39:37 Then, I just quantum mechanics. So, in this way.
08:39:45 This kind of Lawrence ingredients was legalized gravity. I wonder how would end this, if, If it's kind of kind of just a slow moving objects, it will be where you can use just a normal quantum mechanic.
08:40:05 I mean, not.
08:40:06 I mean, not chicken, a lot in some ways but but that may be a long about it so. So, at which point, this HTC ethic, enters into the play. No, no, so So, in, in what we are proposing in the, in the slide you see on the screen, yeah has nothing to do with
08:40:22 relativistic masses order MC video that was a comment I made it really about the theoretical analysis of the Schrodinger Newton model. Yeah, yeah so so it's like you don't get that were bending over light, light there.
08:40:39 When you have a ton of life you are using admin relativistic nature of the light right so so you're saying I mean UX in this experiment this also enters.
08:40:50 They get it right.
08:40:52 No, no. In this experiment, there is nothing to do with the relativistic nature the masses are I mean they're, as I said linear eyes, basically very slowly moving and.
08:41:05 Yeah. So, this is the not Tesla renting variants or any such thing. I see but but then them to me sounds like a normal quantum mechanic because in this way it is instantaneous interaction.
08:41:18 And in this way.
08:41:21 locality of the CD a short distance whatever does not enter you know, because you can say is it just the longest ancient something is interaction. I mean, I think, you know, no I think you're correct.
08:41:35 I think we are back to the discussion we were having yesterday. Yeah, like, towards the end.
08:41:40 Okay exactly are we testing in these experiments I think that is a valid question, I see.
08:41:52 No, I wasn't
08:41:52 even perspective, in this case, no, you're saying that his model is the same right I see no I mean yeah so so my present state of understanding as we show in this sort of its effect as I said, the basic fact is that the gravity actually in the differential
08:42:06 mode or not in the common mode. So the only affect the observable effect is a shift in the oscillation frequency of the common of the differential mode, with respect to the common mode.
08:42:21 Because.
08:42:22 Yeah, so I do not know to what extent you will interpret that. I mean that has nothing to do with quantum mechanics per se. Right.
08:42:32 Okay.
08:42:34 So, Mariana, did you have another question.
08:42:37 Yeah. So, yeah, yeah.
08:42:39 No.
08:42:40 Okay, and Igor you also had your hand up, but you don't anymore So did you have anything.
08:42:47 Alright, thanks. Well I just had a quick comment because of the question about the pH guy to experiment on shooting and use it but I think I'm you Mitch said it precisely right, there's this crucial additional assumption that you have this kind of many
08:43:01 worlds interpretation, so it's a classical experiment actually but with this additional assumption, you assume that you branch off all the time in all different possibilities.
08:43:11 And then you take the average of them. So even then classical experiments would give you some, some signature. So it is a you know a tongue in cheek experiment, like said but it is under this additional assumption.
08:43:22 So I think it's very valid also inappropriate in the quantum realm.
08:43:27 It's two different things. This experiment and page kangaroo.
08:43:31 Yeah, thanks.
08:43:37 I'm helmet, so I was also intrigued when you mentioned experimentalists were sort of preparing experiments for having to do with holography.
08:43:50 And you said that the theory was in development but I was wondering like what are the specific kinds of things that you know experiment and thinking about testing in relation to log or theme because, yeah.
08:44:05 Essentially what what we are, what we are looking for here is correlated noise between to close by, interpret meters. So which which share some part of the space time region.
08:44:22 And so, yeah, I mean, I can only say it as I, as I said, said before maybe the, the, the holography aspect or the longer fee idea here is that, due to the reduction of information so if the holographic principle holds then there must be some reduction
08:44:44 of of information in in three dimensional space time, for example, and so the consequence of that would be that the path length noise that the light accumulates when it travels in these arms.
08:45:03 Due to the space time over level these 24 meters should have some, some correlation, because the because the information in this in this volume cannot be completely independent that cannot be completely independent space time quantization noise in in
08:45:22 each plan was for example.
08:45:32 So in that sense it's quite speculative, but in, depending on how you apply it you could you could maybe see correlations between the so there's a little bit of theory work from home but not at also from work and well in that look into this idea so it's
08:45:56 it's certainly under development but the idea is there some, some correlation of noise, due to inflammation reduction pathetically.
08:46:04 I see, I see. Yeah, this is Doug, let me sharpen up that question will check and collaborators have worked on this and find that the flux in the correlated fluctuations are only on the scale of the Planck length, independent of the length of the interferometer,
08:46:17 and therefore as you already said, an observable. However, I've millennia zero propose is the effect goes as the square root of the length of the apparatus that is the variances add over length.
08:46:32 you expect you to distinguish between those two possibilities.
08:46:37 Yeah, I mean, I think.
08:46:49 The Rick and Linda are working right now on predicting Apollo spectral density so this this would be the equivalent of what we can see in the experiment, so we have to see where that where that gets us whether we can without, or not.
08:46:57 But, in that sense it's a it's a proof of principle experiment that.
08:47:02 Yeah, we can we have, we have to see whether it's whether the calculation ends up.
08:47:08 Okay, I think we have to move on to the next talk, Andrew. Maybe we can take your question to the general discussion.