 Maybe we can zoom on a tissue, okay, a tissue, I think we can start. Okay. Okay, thank you, Paulo. So welcome all of you to this colloquium on ego and Virgo, the past, present and future of the physics of gravity waves. I'm very happy I'm very pleased that Professor cuts cut some of us and Professor Chella, they agreed to travel and being here present in person and campus on this occasion. And I hope that all the students will benefit from, you know, interacting with them. I was not able to, I'm not able to attend in person today because of COVID quarantine. So, but I look forward to the talk online. Let me say a few words about the speakers today. I'm a young car load cell. He's a senior researcher at the INFN. And he has worked at the National Institute of nuclear physics. He has worked in high energy physics and that is guest theories and his current main interests are in gravitational waves, both from from a phenomenological and from the detection perspective. I'm a member of the Virgo collaboration. Since 1996, and currently is the data analysis coordinator of Virgo and co chair of the LIGO Virgo Kagura collaboration, which as you know is this consortium of these various gravity detectors. We have a data analysis council and group leader of the Virgo PISA group. And then Professor Stavros cuts on us is a professor exceptional classic exceptional at the University of Paris, the director of the European gravitational observatory, which is caused by the name of ego, hosting the gravitational antenna in PISA. And he has also been the director of the laboratory of astroparticle physics and cosmology in Paris, deputy director of National Institute of nuclear and particle physics and CNRS and first chair of the European consortium of astroparticle physics. He is his work in particle and astroparticle physics and is working now at the interface of physics and geo science and art and science. Also, and he has received the order to show value and the show value of the national demerite demerite in France and physics prize of the Academy of Athens. So, ego is the was created about 20 years ago, together with the French CNRS, the central national that I research scientific and the Italian INFN, which is this Institute of nationality, physical and nuclear. And for the last 20 years, Virgo experiment was constantly updated and improved with the expectation that it will detect gravitational waves sooner or later, and these extraordinary efforts were rewarded in 2015. Then the gravitational waves were detected. As you all know, we've heard a kind of, so I should tell the speakers that the audience is really primed. They have heard a very nice introduction to the subject from our direct medallist Alessandra Bonanno, just last couple of weeks ago, as part of the salam distinguished lecture series. And it's, it's a really fascinating and exciting field of research that is really going to open up new vistas onto the universe. And so it's a particularly appropriate that now it's being followed up these lectures by the what is possible observationally to do in the coming years. So I would request Professor Caminelli to moderate the questions and answers following the presentations. And without further ado, I would leave the floor to the speakers to explain to us these exciting experiments that are taking place. Thank you. I would like to thank everybody for inviting me in this wonderful place. And my plan is to discuss, I would like to discuss a lot of material but there is a limited time so I choose to collect several slides but I will tell you during my presentation, only the basic So it's okay now. Okay, so my plan is just to move through the slide and tell you the basic point. But please, there are several details that I will not be able to comment on. So if you are interested in more depth information about some particular issue. Tell me a question and we'll try to do my best to answer. So, moving on, I, I tried to put together something which has to do with the very good life of science and science is not only science or what we observed but also science about the way in which we are able to observe the way in which, the way in which we build our detector and the way in which we try to make it as much sensitive as possible. And what we are looking is gravitational waves, which is waves, as you, everybody of you knows, is a standard prediction of general activity. It is standard, but it's interesting to note that for several years there was controversy about the fact that these were real or not. Now there is no doubt, of course, that they are real. And, but, okay, all is based on the basic equation of the general activity, which is the, let me try to do this. This is the Einstein equation, which by taking by itself is a complicated equation. It's really a system of 10 differential partial differential equation, no linear. And so it is difficult to solve it unless you use some particular assumption about symmetry, for example, or you use some particular approximation, for example, weak fields. In fact, it is from looking at this equation from the point of view of weak fields that we can understand what gravitational wave is. In the most common framework, you get a basic solution, a very simple solution for the Einstein equation, for example, the Mankowski space, and you perturb it a bit. And if you look at the linear equation that describes this little perturbation, you see that essentially this small perturbation follows a wave equation. And at the end, we understand that as this perturbation or perturbation of the metric, this is often described by saying that wave, gravitational wave are simply perturbation of the fabric of the space time that are free to propagate. And another prediction of general relativity is that they propagate at the light speed. This is an expected consequence of relativity, and as the source of the gravitational wave is the Timor-Newt answer, they are expected to carry direct information about mass and energy of the source. This is also true that the coupling is quite small. On the negative side, this means that to produce a relevant quantity of gravitational wave, you need very massive, very compact and very fast sources, but on the other end, this is also in some sense a bonus, because direct consequence of this is that the gravitational wave produced in the first instance of the life of the universe are able to propagate essentially undisturbed and carry to us relevant information in principle about the source they generated. So at the end is the effect of a gravitational wave. You can try to figure out a set of test particles which are mass, which are unaffected by any kind of interaction apart from the interaction with the gravitational one, and the effect of the gravitational wave which is passing is depicted in this animation. General relativity also predict that there are only two different independent degree of physical degree of freedom, which we call transverse and tensorial perturbation. In principle, there are several generalizations possible of the theory that predict that also other physical polarization or other physical degree of freedom can be present. Anyway, what we do in Virgo and LIGO is try to catch this and instead of these small dot red dots test masses, we use mirror, which are not really in free falling because we need to suspend them, but in the appropriate regime of frequency, they can be considered essentially equivalent to freely falling masses. Well, what is the scientific output that we can get from by studying gravitational wave. For example, it is a new tool for testing general relativity. And an important point is that this is a test that can be done about general relativity in a regime which is both dynamic and strong field, which is not the case for example the classical test about mercury precession or things like that. So this is something that we can access only in this way. And as I mentioned before, this is also a way in principle to look at signals that are generated in the very early universe. So also the possibility for specific source to look together to the generated gravitational wave and also other kinds of messenger, for example, optical electromagnetic or neutrino one, and by putting all together we can gain a lot from different and complimentary perceptive about the source. Right, you see that starting from the general activity which is the unique to be with a massless metric field, you can have a huge amount of possible generalization, and each of them give a particular prediction about the peculiarity of how these gravitational waves are composed that I mentioned before polarization but this is not the only point, and also unique information about the way in which they are generated by a specific source. So, in perspective, this is also a way to not only to test the general relativity, but maybe also to constrain and to choose between possible alternative. And I will try to improve our observation, the basic observation of course has to be something that is independent on the coordinator this is important point in general relativity, because the general activity is built from scratch, in such a way that it is independent on the particular reference frame and coordinate which are, which is chosen to describe it. And one simple observer, which is gauge independent in this sense is just what we measure we send light toward a mirror, and we measure with our timer, what is the time it makes to come back and forth. This is basically the principle, and there are several way to describe these in the context of how an interferometer work, which are coordinate dependent in some coordinate the mirror is moving as an effect of the gravitational wave. Another, this is not true, and the fact is only on the propagation on the laser speed, but at the end, whatever is the way, whatever is the way we use to describe the apparatus, the final observable is always asked to be always the same. In a particularly same simple picture, which is the one which has experiment experimentalist we prefer because it is the one that most simply can allow us to incorporate also noise effect in the description. So we, we can just put ourselves in a local Lawrence and coordinate frame. And in this way, essentially, the one mirror is not moving the other is moving and this movement is proportional to the distance from the first one. That's the reason why we needed to make an interferometer of three kilometers or four kilometers of land, because as much as as larger is it is as better it is. It is just a simple factor amplification of the signal. Of course, the real detector is a bit more complicated. We are not only a single mirror, we have a two mirror, and we send to a laser which is pleated and recombined and essentially what we look at is the difference of the round trip of the laser in different directions, which if you remember the picture I showed you before of a gravitational wave which we which stretch one direction and enlarge the other is in some sense of the optimal things to do. Okay, I can skip this because it's a bit more technical, just to say that the real interferometer is still more complicated for reason improving the signal to noise ratio we build a cavity on each arm, and this is something that can allow us to have in some longer cavity, effective longer cavity than three kilometers. This is not completely true because of course there is no noise which not scale always as we want, but this is the basic principle. So, the basic takeaway. Okay, before the takeaway, I show you how detector is able to respond to gravitational wave which comes from a particular direction, and this is the picture by this kind of been picture, which is a polar diagram of the coupling as a function of the action of the arrival, and you see that there are some blind spots, but apart from that, the response to the coupling to gravitational wave of interferometric detector is not particularly an isotropic. We have several of them. The most sensitive are the two lack of like of four kilometers and and here go. The right there is also geo that historically is important and it is also important from experimental point of view, because it is important test the bed for advanced technology, and now we have also Kagra, which is entering in the game, still not with the good sensitivity but we think that this will improve a lot in the following month. And, okay, before proceeding, just keep in mind what is the anatomy of a detector output. We have several of them. So we have a detector index and for like over go Kagra, and we have two pieces, which are addictive, we have the noise of the apparatus which of course depend on the detector, and we have the signal which comes to from a particular reaction of the gravitational perturbation of the metric to obtain it with a tensor which described the tensor geometry. And from the point of view of the senior, it is useful to look at this in a very large vector space in which one, why very large because we register we record a time series with many, many, many and so you can have to look at vector space with such huge dimension. The noise is a vector in this space, which is random, we don't know exactly of course what will be the, the noise of the detector in a particular measurement, while the senior typically will know about that and we know what direction is this and the important byproduct of this representation is that if you look at the picture of in the first event of in the first detection without any kind of cleaning, you see nothing you see just a huge amount of noise. But the first lesson is that there is a part of the noise which can be clearly distinguished by the signal essentially by taking the only part that can be confused with the signal is the projection of this noise vector over the signal vector and if you remove these you can see the picture which you see in the paper in which you see something which is still affected by the noise, but it is clearly recognizable as a way for. And few words about the fundamental noise, which are the enemy that we are trying to fight with. And, okay, we remove the noise from this and one is. Okay, maybe I can skip this. This is a general picture. And this general picture tells us that a convenient way to represent the performance of our detector is to show the spectral amplitude of our noise as a function of the frequency. This is the amount of the energy of the noise in the senior theory sense, which is inside the given frequency bin. And so, from here you learn that we are sensitive in the window, which is more or less between a couple of 10 of us toward a few kilos. In this region, we reach a sensitivity, which is of the order 10 to the minus 23 or less, which is a sensitivity in a spectral amplitude of the strain and the strain you can picture the strain in an intuitive way as a relative deformation of space. This is small. And if you scale this to four kilometer you see that you have to be sensitive to a moment of the mirror of the order 10 to the man minus 18 meter, which is quite quite small. And of course, the problem is not that if there is no noise, if there is no noise, we are sensitive, essentially to everything. But the point is to understand that what is the perturbation, which can mimic a senior which is introduced by the noise. This is seismic motion, seismic motion, earth is moving continuously, and the scale of this motion is one meter on typically, which is many, many other magnitude larger than 10 to the man minus 18. So it is not possible to put the mirror on on directly on the earth that we should isolate them from the ground. And this is done essentially with a long chain of pendulum, the transfer function of the pendulum is something like that. And you see that above the resonance of the pendulum, you have a reduction of the noise. And this is reduction is much steeper if you have several stage, you got additional bonus of one omega square power for each stage of the pendulum. And so in this way, you can reach what respect, which is essentially in the relevant frequency region, a reduction for factor of 15 order of magnitude, which is which I think could seem impossible, but we are doing that. Another important source of the thermal noise which is the fundamental limit in the most interesting and most sensitive range of our detector is thermal noise, which is just the coupling to the environment in the statistical sense. And we are trying to reduce we are continuously trying to reduce this one way is to enlarge the spot of the beam, which given average, larger average of the fluctuation of the thermal fluctuation the surface. Another point is that to remember that the fluctuation dissipation theorem tell that the fluctuation is proportional to the dissipation. And so we needed to reduce as much as possible dissipation inside our detector. We can also try to use cryogeny but this is not an option for LIGO for Birgo. It will be for a future detector and for Kaggle. Maybe this is specific kind of thermal noise that I can skip on that. Another important noise is quantum noise. This is interesting because tell us that we are so sensitive that at least in some frequency region we are quantum limited and we are limited essentially by the indetermination principle. It seems that this is an inescapable limitation but this is not true. And the point is that we do not really need to measure the motion of the mirror, we just need to get information about the force that is moving the mirror. This is something that can be done by evading a quantum limit with several different, there are several different proposals and one in particular which is the inaction of a squeezed state of light in the detector is the one which is currently adopted and we are seeing it at work. It is also true that in our detector we are seeing the interplay at a microscopic level between classical and quantum physics. Okay, maybe these are also other details that you can skip from now if you are interested. Let me know. And maybe also this. Finally, just a word to tell us that there is Newtonian noise. Newtonian noise is just the effect, for example, the motion of the earth, but not direct. This is not the fact that it is shaking the mirror. It is the fact that this motion is generating a progression of the mass density in the background, for example, and this generate a fluctuating gravitational field, which is not a propagating gravitational wave, but locally can mimic the fact of a gravitational wave. And this is also something that. Maybe it is more. Sorry. I'm not able to come back. Okay. Okay, so this is something that we are starting to see now. We are in the low frequency region and we are trying to mitigate it by testing super subtraction techniques. We measure the motion of the ground and we try to gain information about the noise and to predict or another option is to move in a place which is a good from the point of view assessment for example in Sardinia. This is not a story about senior we are hunting for several kind of senior. They are classified roughly from the point of view of the shape of the signal. There are bussing, which are quite short, and they can be generated, for example, typically by core collapse on massive stars but also from peculiar phenomena, for example, from kings and cusp in cosmic stealing the loop. Coalescent binaries and now there is this green cross that tells us that we see we saw both the black or black or new society and black or new society coalescent binary now. We have a signal which is well known theoretically and we know the template and we can compare the template with the data in order to check if it is inside our data or not. We have a more longer continual signal quasi periodic signal, which comes from spinning neutral style. We can be isolated or not. And finally, there is a stochastic background, which can be generated by astrophysical sources but also, and this make this very interesting for a simple scientific point of view by several mechanism in the early universe. This is the same picture, classified in terms of the frequency, and you see that we are here, essentially, and we are able to look at some class of sources but there are several others, which are out to the realm of the possible source for detection as I said a few years ago, but there will be an option for future detector of different kinds, but this is, again, another story. Okay, I think I can stick keep this. Now I will concentrate on the class of senior that we were able to detect that until now, which is the collapse, coalescent binaries. As I said, they are welcome. Well under control from a theoretical point of view. Essentially, the picture is that you have two compact object. And these two compact objects are orbiting one around each other by doing this generate gravitational wave lose energy, and at the end merge together. This is the first phase of this evolution, which is there so called a spiral one in which the source are still quite far away. And this is well under control using perturbative techniques post Newtonian expansion, for example, but at some point the two objects become so near that large gravity effect starts to play a relevant role and this is a realm in which we have to use numerical relativity prediction. How we look at this. As I said, we are looking at this by using the optimal an optimal search, which is the one that we can apply to the signal, if we know what we know what is the shape of the signal, which is to compare the data. The signal is in blue, the red one is a template that we are comparing and below you find just the scholar product of one of the red on the blue, and you see that when the template match the expert signal there is a big. I said that we know the signal, but as a matter of fact we know the signal as a function of some unknown parameter, for example the masses of the two objects. And so the search is really more complicated. We have to do several comparison as the one depicted in the last part of this picture. And we have to test a huge amount of different template. This is a representation of the of this template bank with the density of the template on the parameter space of the two masses. And the density depends on the fact that we have to space it not so so they are not to be too much space because it is if this is so a senior can not be touched with good efficiency. If it is not near one of them. Well, it is also important to have the shape of the senior well under control, because we have several different cycle in the spiral phase inside our detector. And if we miss half a cycle during this time spent by the signal inside our detector. We strongly the create the grade the accumulated the signal. For this reason, also in the perturbative sense we need to move to very higher order of approximation in order to control the phase of the signal with enough precision. From the point of view of the sensitivity you have a scenario like that. Yeah, we are as a senior as a signal is quasi periodic. It makes sense to see it moving in the time in the frequency space. Here you have something that is entering from the low frequency region. At some point it becomes visible by our detector, and it stay inside the relation band of our detector until there is a merger. So this merger is, of course this merger up and yearly is the object for example the black hole are larger. And so if you have a senior which is quite if you have a very massive couple of black hole, you will have a situation which is more like that. And the signal will stay less time inside the detector band, and at some point it will not enter in any case and so to give you black hole cannot be detected by very good life. Another tool in analysis is just a base theorem. The idea is that by by applying the base theorem we can just give a posteriori distribution of the relevant parameter of our source. And this is the most complete and the most current approach that we can use to analyze your data and we show you some example in the short time. For continuous waves, it is for sure possible to think about applying a template search, but if you make some back of the envelope evaluation, you realize that in order to do this really, you need a huge amount of computational power. So, a other approach are chosen, and the typical the senior least chocolate pieces, and each of them is searching with a template and after that, there is a non coherent search about the bastard the boss is not structured and this also poorly know from a theoretical point of view from the point of view is shape. And so various me to the look at the senior using the minimal assumption, essentially they are searching an excess of energy, and clearly this reduce the sensitivity. Finally, the stochastic background stochastic background is a senior, which is not described by a given template. It's not a matter by a stochastic process. And so, all we know about this stochastic process are their main statistical parameter. So, with a single detector, it is not possible to detect stochastic background, but if we have two or more of them, we can correlate the senior measured, and the idea is that when you correlate the output of these signal, you have several correlation signal signal signal noise noise signal noise noise but one only in an average sense only the correlation of the senior which itself survive. Of course, if you assume that there are no correlation between the noise in the different. The scenario for cosmological background is very rich. There are no candidates which can be seen as promising one for a very near detection. I will say that the most, the most typical one in from the point of view detection are a bit speculative but anyway we are searching about this and we are looking for this. First five years of observation. Of course, in these five years we are we added the first detection. I think that everybody knows about this picture of the joint observation from and for the limestone of a coalescence of two black hole. And here you can see what I told you before that it is just a clean version of what you measure, because essentially we keep only the amount of noise that which is comparable that can be confused with the signal but anyway you see, there is a clear evidence of the signal which is in very good agreement with theoretical expectation but anyway, this is only a part of the story. And I have also to mention the first detection of a binary star. This is something that happened a couple of years later. And in this event that was really very important event and very and also very evident one. We see not only the effect of the coalescence of to a couple of new style, but also a gamma ray bastard, and also a plethora of other counterpart in almost every frequency range of the electromagnetic band. And this is very important from several point of view, it is, it was the first occasion to look at the possibility of gaining information about nuclear matter equation of state of Newton star, which is a very important scientific problem. Of course if you look here, and these are two predictions for the distribution of the energy of the signal for this kind of coalescence using two different variant of a question of state for the nuclear matter. And you see that the difference show just in the high frequency region which is not at the moment most sensitive one for the detector. So at the moment that we are just, we can just saying something and to exclude maybe some particular extreme model for the question of state but this is something which we expect to improve a lot in the following. And of course, I have to mention the fact that there is also, there was also the Kilanova regime during this coalescence, which was also discovered for several weeks and months after the coalescence. And now the last run, the last run we had, here you can see during the full history of our measurement with second generation detector how the number of events is And you see that there is a change of the rapidity of the rate of the events that we detect, which is simply explained by the fact that we are scaling the sensitivity. And when you scale sensitivity of your detector by a factor two, you are scaling the exploited volume by a factor eight. So also relatively small from some perspective improvement and sensitivity can give us a large gain for astrophysical measurement perspective. This is the plan for the future measurement we are now here, we are preparing the O4 run and we expect to start with sensitivity, which is maybe a bit better, I will say something less than factor two compared with the previous one. This is a similar picture, a snapshot of all the 90 events that we see at the end of this series of run. And this picture is also interesting because it shows you that the number of cumulative detection scale as expected with the effective time space volume explored by the detector. This is not strictly true because at some point when we look very far we can start to look at some difference in the way of the rate depend on Z, but at the moment there is a good scaling. This is another snapshot of the estimation for some of them we have several of them. Some of them were quite peculiar and deal to peculiar work and analysis by itself, I will show you very briefly some example. This is not the way to classify them in the plan in which we have the chirp mass, which is the most relevant global mass parameter for the source and the mass ratio in the vertical axis. And you have several regions. The green one is the one in which you expect to see events from black or black or coalescence. The yellow one is the neutron star black coal coalescence part. And the pink one is different size neutron star and we have a couple of them inside. There are several analysis that we perform one is the search for gaining information about astrophysical population distribution, and we are starting to tell to obtain interesting result. This is a sector in which we really improve in the future because, as I said, the increasing sensitivity means increasing the number of detections a lot and so gain a lot in statistics. I don't think I have time to discuss the details here. Another important analysis we do in a routine way is the testing of general relativity with several different tests. And, by the way, until now, general relativity work very well. So we have no evidence of any kind of violation but we are. Okay, again, I'm moving. But again, we are searching for these both housing using some assumption or without any kind of particular assumption. Okay, maybe I think it is a bit late so I will skip about almost all the details for these events. There are events like this one in which one of the object is our uncertain origin in the sense that we are not sure about the fact that it is a black hole or a neutron star because it is an intermediate mass range which is poorly understood. In this case, we have a signal which come from a couple of objects with a very large mass of symmetry, and this trigger the announcement of higher order contribution in the signal. This is not only the basic quadrupolar mode but also higher order mode and these these allow you to do more refined test of general relativity and also to constrain better the parameter because it is much more constrained. And this is similar I will skip about that this is also interesting because was the evidence for a very massive event. The point here is that one of the source was if interpreted as a black hole is just in the region in which you don't expect that the black hole will be formed because there is a regional instability gap. There are also other possible explanation for the formation of this object, for example, it comes from the coalescence of some progenitors, but it is anyway interesting and also this explanation is not completely without problem. Okay. About the Newton star that call this is the first example of an event of this kind here, we could expect to have a tidal disruption or the new start but this is not the case in this case because the black hole was too large to create this such a large tidal force of the horizon to trigger this. And I can skip all these. And I just mentioned that we are also doing starting to do and improve multi messenger search as I said that also cosmography, we are looking at the information about double cost and from this way, which is currently not competitive with the most standard one, but it will improve when we go statistic. We are looking at gravitational lensing of gravitational wave two. And, of course, we are looking at bars that are rotating is related star and several information that comes from stochastic background search. I will skip. I have to skip about that. We are also looking for information about the possible candidates of dark matter. Here we have several possible effect. And that can be the effect of dark matter field on the dynamics of the traditional source but also diet evidence that coupling bodies with the detector. I have no time to stay here. I would say they know for we expect a huge scaling of the number of events. And I think I can stop here. The questions to later so we have the second part of the colloquium so we can have all the questions afterwards. I followed many talks about gravitational waves. I think I suggest that you use the slides of Jean Carlo because it's a very complete presentation and then it was really very interesting to me also to follow it even on the things that I thought I knew. So for me so I have the same excuse to make too many slides so I will go fast consider them as a teaser of what is coming and not the real going in depth. So, let me start presenting that you know start by the fact that it is gravitational waves is a story of patients it took 100 years since the prediction it took 40 more years. To see whether we can actually see them or not around the 80s, we had the first proper ideas about interferometers and of course as you just seen, it was only 2017 100 years later that we saw them. It's also a long story of institutional discussions and, you know, funding and etc etc. It was for instance, as I said, as it was already said the ego was founded in 2000, long before no longer for three or four years before it was a decision to start constructing Virgo. And then we approved around 2010, the advanced Virgo that finally saw what you just saw and we were actually have I started with two members CNRS and the NFN and Nick have joined this year. The NFN NFN NFN NFN NFN is a Dutch institution and of course in 2021 we were also recognized by IEEE as a IEEE historical monument of technology. Many, many people have wondering what is ego what is Virgo here I have a big list I will not go through it. Essentially it is supporting the operation the upgrades of the and also some things of representation. of societal impact, trying to increase the societal impact. It's open of course to future possible programs like for instance, the third generation Einstein telescope on gravitational waves. In comparison Virgo, it's a very large collaboration of 723 members belonging to 129 institutions in 16 countries. And you can see the effect of the discovery, double the authors and triple, no, not triple. Yeah, I think it's triple the people working on it too. So you see it's obvious and it's going on every day. And many, many, and I invite you in the summer, we have a lot of internships where they just, we see an explosion of people coming to stay and work with us for a few months during the summer. So this you have seen the different types I would be going very fast on the possibilities we'll have on each new detector that we'll be proposing. Not I will be proposing, I will be describing. And you have essentially what it was already said, the coalescing binary systems that we have seen most of it, but then we have continuous sources, we have burst sources and we have the, let's say the cosmic background or general the stochastic background. And we go from the known to the unknown. And of course, there is always the unknown and then we had these two exceptional years. I will not go through that, you just heard about it. And then we had also the fantastic event of multi-messenger announcing the multi-messenger astrophysics. And for this reason we became a very good historical milestone of technology with all the impacted head in all areas of fundamental physics from cosmology measured a value between the tension we currently have in the Hubble constant till nuclear synthesis, till astrophysics and nuclear metaphysics. I think I want to show though is this one is it is how we manage in this event, you see the spectrum on the right, how it moves from the first second till two months later. So we follow an event that happened 150 million years ago second per second in the beginning and afterwards a little bit more till two or three months. This is an extraordinary thing. And I mean, I always enjoy showing this picture to show why this is a big revolution and why we saw it. I mean, 70 observatories around the world saw that. So this is a global observation. And of course in the last run, you've just heard everything, all the things we saw, the densities we saw is just for those that have short memory to relate to that. This was called the run 03. And I also remind you the picture of the interferometer and I would like to stress the fact because this will be important that we have three fronts. The low frequency front, which is essentially environmental front. We have to see with environmental forces. The middle front, the middle frequency front, which is a thermal front. And the last one, the high frequency one, which is a quantum front. And addressing these issues is the way to go forward. I mean, actually, why doesn't go forward? Yes, and not only that, it also addresses different kinds of physics. For instance, when you want to go to low masses, you go to high frequencies. And also you saw and you see again, when you want to see the end, the ring down of the merger, you have to be good at high frequencies. In the middle frequencies give you more range. You go deeper in space. And the lower ones give you access to the higher masses. So you have to have in mind these three and this is the strategies that will be defined. Of course, there is a lot of technology around it. I don't have the time to go through it. And this is why we claim that we are promoting not only curiosity science, but also technology. And of course, there is a lot of computing, which I will not go. It's global computing between the US and Japan and Europe going back and forth. And not only that, we have what we call the distribution of the low latency signal. When we see something or when they see something, they immediately communicate to us within a minute. In the beginning, it was much longer. These days is around a minute. And we want to go even lower. And this has obvious relationships to climate, change and natural catastrophes. So what are the next steps? Now we are at the point where Giancarlo stopped. What do we call phase 04? We'll do the following thing. We will increase our frequency dependent squeezing potential. We will try to cancel the Newtonian noise that is these changes of density that you cannot just save by using superatoniators. It's just Newton, M1, M2 divided by square. And of course, recycling of the beam, which we did not have in the Americans had it. We did not have it. And this would bring us closer to the American. And of five, it will only be an affair of mirrors. We have to change to have better mirrors. So let's say in the 04, we have lower frequency and high frequency correction in 05, middle frequency correction. So if you put all these things together and you put also the dates, you see that for instance, by 2026, we hope to have of the order of, I calculated for you, we hope to have of the order of 5,000 events, okay? Is it enough? Probably not, but it certainly would be a big change. And then currently we're studying post-05. What will we do after the 05 run? And there are many ideas. So this is publicity of some, we have in our, go to our website, and you see we have nine very nice posters on gravitational waves and multi-messenger physics. It's not only gravitational waves, but it is also a worldwide network of instruments that we, and we have to distribute alerts with that with all these people. And we started having colloquia and workshops around them talking with neutrino people, with photon people, with, you know, with visible light people, radio people, even cosmic ray people. So it is a very interesting work on, this was the last workshop happened a month ago, not even a month ago, two weeks ago. Another slide, just for the beauty of it, it's like a piano that goes from one hit per universe, one note per universe to of course, the Planck frequency, which is a very high frequency. And you see it will have many cartographies in comparison of these cartographies will bring certainly new physics, certainly a better understanding of what we're doing. Post of five, the idea is currently, if you, it's a big list, I will not go through the big list. If you see it, it's all about what I just said, the three fronts, low frequency fronts, environmental control, thermal control, better mirrors, better stability and things like that. High frequency, and that's high frequency, it's quantum logic. Now, let me go to this story of frequencies. It was shown in a different form already, but in Giancarlo, you have the acoustic frequencies that we can call, which is a terrestrial gravitational wave detectors, and you have the lower frequencies, which is Lisa, and I, although it's not yet pretty, it's not yet very, I'm sorry, go back, I went, was happy, trigger happy. So, and there is another possibility that I would just for fun, I will talk about, it is this proposals for deploying gravitational wave antennas at the moon. Now, the first thing that we'll do, the third generation on Earth will be to extend our range, as you see, beyond the first times of formation of stars and galaxies. So, if we see, for instance, black holes down there, they are probably more deep. So, that's a change in our model. So, this is the project of the third generation. In Europe, it's called Einstein Telescope. It's an S3 roadmap, leaded for the time being by Anif and Nikif. France is very interested, but it's delaying. And the timeline is that it should be operating around 2034. And there is a lot of activity, a lot of people working on it. And there are two sides. There is a German side that also is coming up, but for the time being, it's a little bit late. So, it is Sardinia. And the Euregio is the three national points in the Northern Europe between the Netherlands, Germany and Belgium. And the question is, how do you marry when you have, for instance, high power lasers? How do you marry the high frequency with a low frequency? Because you produce more energy, you start heating up your mirrors, okay? So, the solution they currently follow is an axiol of what they call axiolophone. I think it's a wrong definition of axiolophone, but anyway, it's a triangular where you have essentially three detectors in one underground. What are the physics? The physics is the things we just said, probably I should not repeat again. It is fundamental physics and cosmology, test of general relativity, dark matter, dark energy, stochastic backgrounds, black hole, neutron star properties, multiband and multi-messenger astronomy and the textural and use of physical sources. So, you see here, I think I can use that, the increase in sensitivity that we obtain. And you see the difference between, I said only, talked only about Einstein telescope, the American solution is called cosmic explorer. And you see that where there is some difference, no, it is here, the cosmic explorer tries to go deeper in the sky while the Einstein telescope tries to go to lower frequencies. And you see the peaks of signal to noise ratio, we can see it here. And you see that it picks in all the stellar type black holes that is from, let's say, one to 100. It is the affair of the earth detectors. And you see here at the red shifts what you would see. Okay. And of course, it's not only an affair of gravitational waves, it's a multi-messenger affair. So, you see here by, a plot by America Branchesi and many other plots here taken from other people, of course. It's the things that you saw already with Giancarlo that would be much better. And as he said also, the fact that we will have a better, I will show that. Yeah, let me wait to tell it later. For instance, the fact that we'll go to lower frequency means that we'll start seeing, for instance, even three hours before the merger, we will see that they are coming to a merger. And this would be great for multi-messenger because you have the time, plenty of time, just pick up our phone to tell to the others, look there. There must be something coming. So that's great. Then in the multi-messenger, we'll have bigger opportunities coming up by LSSD entering into operation by 2024. Also the ELT coming forward. And for instance, the binary neutron star coalescences, we will be able to study with the optical means together with gravitational wave means in large and huge detail. So I hope I'm around to see all this. It looks, it will be fantastic. And the high frequency front, as it was said already by Giancarlo, you have to have high frequencies to understand what's happening after the merger. And that's very interesting to test gravitational wave, the gravitational general activity to test everything. It's a very interesting front. And you will be also able to use the GRBs, the gamma-ray bursts as standard sirens. You could use them and work with them. Okay, here is plots that I can leave but I can put a negative part there. They will, I mean, they will be better pointing but not extraordinary reporting because we're still on Earth. So for instance, less of 20 degrees, square degrees in the sky will be 150 events on Einstein telescope. And they will be sufficient nevertheless to have a good measurement of the Hubble constant. You know that there is a Hubble tension between early and late measurements and there we will be there. And as I said, we will be looking beyond the time that the stars and galaxies were formed and this would give us access to interesting stuff. First, it could give us access to dark energy equation of state. Second, it could give us access to primordial black holes. Coming to Lisa. Lisa is at space, as you know. Look at the, oh, sorry. Look at the frequency range. It is between, let's say 10 minus one hertz and 10 minus four. And again, because you are low frequencies, you will see the thing in spiraling for years before coming to merger. So that's very interesting. And again, you see that for these frequencies, your signal over noise ratio centers and 10 to the five solar masses. So it is the, let's say the profession, the things that they will be doing will be more around the black holes at the centers of galaxies. And that's what it is. And then it will be also able to understand how these things are formed, the environment that they are formed and test the different models of formation. The current model of formation is that you start from smaller masses, of course. And by accretion, you go towards the big masses today. But this has to be tested. Is it primordial black holes? Is it simply stellar masses and things like that? Then you also have the probability that this will be happening in multi-messenger logic. That is that there will be electromagnetic light coming when there will be the diffusion of these events. So that's again, very interesting. And it will be changes of the signal as it was shown by Jean-Claude. Then you have the embryos. You have the big black hole capturing a small mass, be it a small black hole, a neutron star, a white dwarf. Again, there it is an interesting thing which has an extreme ratio. That's why it's called extreme mass ratio and spirals. And also can be multi-messenger, can also get light coming out of it and then would be very interesting. The other thing that you don't get it's a small enough signal and you don't get the frequencies in the ground and the detectors is the white dwarf binaries. And the white dwarf binaries is one of the possibilities of supernova 1A. And as you remember probably or if you've read, supernova 1A is a reason of one Nobel Prize. It was used as a standard Siren, standard candle sensor to measure the expansion and the acceleration sensor to the universe that is called dark energy. So there we don't know yet what is it at their origin of that. If it is simply to a double white dwarf, then with this, with Lisa, we will be able to see quite a few and we'll be able to again to understand even better what we call standard Siren candles. The other thing that we might be able to see is the galactic binaries, things that are all around here in the galaxy that we see electromagnetically but they are low frequency and we will be seeing them and since they will be inspiring all the time, we will be seeing them increasing their signal with the methods as you just heard by Jean-Carlo, you would see their input here, you see that here, their input with the time increasing, the signal increasing with time. And then we will have again here a pre, let's say a low latency signal that will tell us that two objects are in process of inspiring and they will merge eventually, but you are a little bit far. So this would mean that we will see it first as a continuous signal in Lisa and then five years later we will see it. So we have to be patient with that. And then of course the access to the, all of them have access to different parts of the stochastic, I'm sorry for this, not WG is GWB, gravitational wave background. And there are the first order phase transitions which are not the standard model on, but anyway, a difference from the standard model in the very early years called me strings and all that would also be seen. Then my, I mean, for a few slides, a possibility, I'm sorry, a possibility is what about the moon? There are currently three proposals to go to the moon and I'm working in one of them. And the idea is the following, you use the moon as a vibrating sphere. So you just, for instance, in our case, you just put a fiber that's sensitive to the vibrations of the soil and you strangely enough, you manage to detect if everything we say is correct, gravitational waves. This has had already the support of ESA, the support of EC, which is EC, which is to make more and more studies, and not this proposal, the three proposals together. And then in the U.S. in a way we're currently proposing as an F mission to ESA. Now, these are, and these goals, for instance, of LSGA, I will say a few things about LSGA, essentially the proposal I'm implicated with is not only gravitational wave studies, but of course also geo-moon studies and also acoustic studies of the moon surface and subsurface through the impact of cosmic rays. There's no atmosphere, so they hit directly. So these are the four reasons why we would like to go to the moon. 1,000 times less seismicity, better localization because a bigger distance, but also because of the moon in a month when you have inspiring, and so you have more than a month, you can measure it from many different positions and also of course around the earth and around the sun. Multiband analysis, when we're associated to earth, if you have a good measurement of the inspirer and good measurement of the ring down, then you have many degeneracies of the parameters of gravitational waves that go away. And of course the independence of background. So how can I detect it? I just said it, in our case, there is one case where you just simply do a very good at the moon. The case of the two proposals that come from Italy, one is from GSSI and the other one is coming from myself and other people and also France. It is the vibration of the moon because started by calculations by Weber, the historical Weber, Dyson, then Ben Ben-Aim and then these UC Palmer stories these days that actually doing detailed calculations. The solution is you put, as I said, an engineered fiber optic and then what you measure is the Riley back scattering that comes back, you make a phase analysis and so you have in let's say 10,000 kilometers, you have 400 sensors. Because at each point you can have them. So 400 sensors, you have a camera, so you can really try to localize measurement and you measure only the horizontal strain. That's what I'm showing here that you can have directionality and localization. So this is it, I don't want to go into details. They have proven, they say that they have proven and we have tested that also in Virgo. Partly, we are not yet at their numbers, is they have a very high sensitivity, 10 to the minus 13 in strain, 10 to the minus 13 over square root of hertz. And if you take a multiplication factor by the moon that is at the order of 10 to the six, you arrive to 10 to the minus 19 and if you take 400 sensors and you take their square root, you can go around five 10 to the minus 21 in strain which is good enough to see many things. The other concept, it has to be calibrated with a seismometer. And we use there the seismometers of deployed in Mars, inside, in says, and it's a very good synergy. I will not go through that. And a third one that you can do is like Virgo, but you simply use a lunar reflector. You just send the light and get it back. And again, if you make the calculations, you see that you obtain sensitivities that are not very, very far from what I just told. So all the three together are proposed as a solution. Then you have to first attack the seismic activity. I will not go. They are the deep moon cakes which has like earthquakes of the earth. Then all the vibrations that come for meteoroid impacts. And in general, you have what's called a lunar tunnel. You have a very low frequencies of noise that nobody has managed to measure till now. So there is a mission that will go 2024 approved by NASA and ESA, and we are participating into it, which is will do essentially the study of the deep moon cakes because you have here the problem that most of the moon cakes that we had were on the side that sees the earth. So is it simply tidal forces or we cannot see the other side, the first side or what's happening? So that's the far side system will tell us about that. But the thing that you will not be able to tell us is what I just called the lunar ham. The fact that there will be vibrations at the moon and this will be background to also gravitational wave detection. So this hopefully this lunar background ham will be the affair of the LJAF does. And then also why not using the impact to search for water, habitability issues, things like that. These are let's say the practical things that you can do. And then you have the gravitational waves where I just told you that by a multiplication factor of one million you can arrive to have sensitivities that are comparable with, for instance, what happens on earth, what happens in Liza. So you see, and these are the two other solutions proposed by our colleagues in GSI, Jan Hams et al. So you see that you get compatible strains if you're in your optimistic calculation. So always I have to say we're early in the process with that. And then as I said, you will have mergers scenario. You will be seeing a thing years, tens of years before coming. And that would be interesting. Also in measuring the inspire is very good. And then anger resolution as I told you because of the three possibilities, not only earth, moon, but also the trajectory, you will get numbers up to milli arc second, the arc second square and milli arc second. So very, very good precision for a few events. We don't have exactly the number of events that this will be happening. This signal over noise ratio as a function of mass and redshift is here. And as you see, it is concentrated in the central values between the stellar black holes and the center of galaxy black holes. And this is where you see it more clearly. You see where ET will go. It will go up to 1,000 giga parsec or let's say 100 redshift. This is where it's supposed to go with a mooner. So you see that covers the middle and this is in blue is what you have with Lisa. So the idea is to cover the whole spectrum. You can see double white drafts. I will not spend time there. Intermediate black holes, as I said, it is the work of this frequency band. This is where we will be seeing the history from stellar masses to massive black holes at the center of galaxies, the environment and all this. And this can be done. And of course you have as everybody, but in a different parts of the masses and the parameters, you would have access in the stochastic gravitational wave background. You see here, this is the sensitivity and this is the kind of things you will be seeing. And these are, for instance, first order, again, first order phase transitions, leptogenesis, primordial black hole echoes, non-standard models of inflation, et cetera, et cetera, et cetera. There are many desiccers proposals, I have to say. The most known one is the SIGO, but there are also some in the, Magis, for instance, further. And the other thing, the last thing that you might do is that we will calculate when you have the impact of very ultra high energy cosmic ray on the, we calculated, and according to our calculations that again need a lot of testing about a lot of parameters are within ranges, and so we have to be sure. There you might even get three times the Eugé detection area if you're just by the acoustic signal of the, you will hear even the cosmic rays. Imagine that, not only the gravitational waves. So this shows that we would be, the gravitational waves are interesting for all the big puzzles we had, inflation, dark matter energy, matter dominance over anti-matter, formation and evolution of galaxies, structure and role of violent phenomena, the nature of black holes, neutrons, stars and white balls, all the hair, et cetera, will be seen hopefully. And then of course the physics of dense matter and strong fields. And as I said before, not only most, when you use light, you're essentially, you see after the recombinational wall, after 400,000 years. All the events that you see here that happened before the recombinational wall, ground unification transition, quark hazard transition, a closed synthesis transition, matter domination transition, recombinational transition, all give stochastic gravitational wave background signals and would be useful for us. And of course, at the same time, you will be seeing in front of the wall. And as I said, the third generation already will be going very deep close to the wall. Okay, I think, so I think my statement here is gravitational waves are not just astrophysics, it's all fundamental science implicating the entry. And I don't know if I have time, otherwise I stopped here. I would say our social program is four or five slides, not more is, I mean, I'm sure it starts in France. Pascal used to say at the time of Newton and it fixed the universe, he would say the eternal silence of those infinite spaces frightens me. And we tell him, don't bless, don't be afraid. Now with gravitational waves, we've heard in a metaphorical sense, the sound of the universe from the cosmic sublime, which is something as far, but you cannot feel, to something that beautiful, where you can also feel quite here. So this brought our implication in at least the three other fronts. The one is climate change and in distribution of alerts. I mentioned that, that's how we can understand it. I mean, you had a very nice presentation by John Carlon, how we depend on the environment. And so we measure it with a high precision. The fact that we are in multi-messenger gives us a philosophy of multi-sensor reality. We like not only to understand the world in images, but also in the acoustic sense. And of course, education, citizen science and art and science. And so this I have not go through. This is our, I'm sorry. This is all the things that influence our measurements. You see this atmosphere, anthropogenic, electromagnetic waves, sea waves, seismic noise, cosmic rays. Then in society, in society, again, many actions, I will not go through them. I will only show you one that is probably interesting here too. And probably we could make a presentation here. Citizen science program. You have the signals that you know the template, but you also have what we call glitches where you don't know what it is. Most probably most of the time it's of course noise and you have to correlate it all, so these things. And we have a program that we put now on what's called Zoomiverse, a very, very powerful citizen science program where many clicks are happening and people, citizens are helping us classify all these signals and putting machine learning in things and correlating them, discussing. We make also hang outs where we discuss with them what it is. Something that could be also discussed here with ICDP knowing its goals. Then senior citizen science. We teach to the older people of Kashina. We teach gravitational waves and make them use our science, citizen science program. I'm sorry. Sorry. Then as I said, we are honored to have Wanda Diazmer said, which is a blind astronomer and she's leading the certification movement of astronomical data. And this is very interesting. For instance, you can hear her this Friday immediately after the president of the UN talking about these things, about how it's important. You see her here testing something at the. So you can, for instance, what I just said about glitches, you can either have them in image or you can have them in sound. And she says, one of the says that people with blind people will do it better than the people that see the classification. And I believe her anyway, making the two is very important. We prepare a van. We have also this thing that I said to you, Paul, that room that will be in there where you enter and by entering you have a projection on the wall which is an excruciating space by moving. You change, you deform it and you make it another kind of space. Things like that to play. And then the posters that I just shown some here. I'm sorry, I'm finishing. Then a lot of art and science and exhibition called the writing of space. In the passage of the year in Rome we had an exhibition. I mean, it was of course with lasers pointing at the gravitational wave detection points. At the same time, certain music with spiders and things by a very well-known artist, Thomas Saraceno and many presentations in art and science events. We are part of the, as also is ICTP of the International Year of Basic Sciences for Sustainable Development. And then our ambitious project is to have a laboratory that will put all this in function. Thank you. Great. So there is room for a few questions, somebody from the audience. Maybe I start with a question. I mean, maybe for both, but I wonder now that the two collaborations are sort of together, how do you deal with upgrades in a sense? How do you decide, if you decide to go for a certain technology, is there some competition between the two? So you are choosing different technologies or do you decide independently, decide together? What happens? I think you have to turn it on. Okay, so two things I would like to say. First is that, for instance, in choosing the new coatings for the mirrors, our groups, Virgo and LIGO groups, and also Kagura, but essentially Virgo and LIGO, discuss them deeply and we chose the same solution. So there is very close relationship. There is then, for instance, in computing. Again, computing, we are going towards a merging of the two teams and what is called EGWIN, has a like ping-win. It is the International Gravitational Wave Network where we will be, you will not know where it's happening and how it's happening, et cetera, et cetera. We are going, something that's sure indeed, but it'll be probably different, not localized, we try to do. So there are many places technically where we collaborate. Something that is a difficulty, because I like to talk about difficulties too, every time, to be honest, is that, for instance, now with COVID, we have different environments. So there was a discussion when we start together because if one of us starts long, as it was explained by Jean-Carlo, will not go far. We have to have at least three to work. So there was a big discussion when we start. This ended very well, which was, we start December of this year. But it was a discussion back and forth. Now, then afterwards, we have more changes to make than they have and then there's some discussion still between oh four and oh five, will it be one year, one year and a half? But we're at this level, there is the discussion is always, I think we'll find a good solution anyway. So, but there are places of discussion and there are places where we merge. Did they forget an area? No, I think these are the areas where we collaborate. I would like to ask, what are the main challenges to use squeezed lights in these type of experiments out there? Well, the basic principle is the following. To the first approximation, we have a laser and we describe it as a current state. Now, the information about the signal is encoded in the phase. And so if you have this blob, which represents your current state in the quadruple space, you have two ways to reduce the indetermination in phase. One is to move this far from the region, which means using powerful laser. The second one is to change this to a squeeze state, which is space, sorry, which is phase squeezed. So, you can have a large indetermination on the amplitude, but you can reduce the phase indetermination. This is not the end of the story because the light is impinging on the mirror. And so if you increase the amplitude in uncertainty, you increase the fluctuation in relation pressure. And so you reintroduce the noise. But if you do this in a proper way, and one challenge is that the proper way is to find the best compromise between phase squeezing and amplitude squeezing and rotations and squeezing angle at each different frequency, because the mirror reacting different way at different frequency, you get the optimal solution. And you can essentially evade the quantum limit. And from a technological point of view, a squeeze state is delicate. So if you're in your optical apparatus, you have losses, you mix your carefully prepared squeezing state with something which enter from the outside, which is not squeezed. And these are rapidly destroyed your squeezing. So one important challenge is to reduce as much as possible the optical losses inside the apparatus. I can answer to one of the questions probably you. We failed to show there were two questions. One is, my question is how to estimate parameters in the Inspire and Merge and Ring Down. For example, in system GW-1509-14, we failed to show one plot where you see that, for instance, in the Inspire, you have the mass together with the inclination and this we have probably, I will let Giancarlo reply to that. But certainly when you put all of them together, you take out where the generous is. But I would like to answer to that. Yes, you're right. It's a very, very good question. We will need to improve the signal matching, event classification, algorithms to accommodate the larger number of detectable events after increasing the instruments in spirit. Certainly because essentially also the speed, the speed will not be, I mean with all the events that will be coming, we have to have a good way, new methods to find the classical world machine learning, things like that, good methods to identify, to template matching as it's called. I mean, to see sure that the template is the signal and then from this, when you have the, we extracted the signal, then you can start extracting the parameters. So I would like, I don't know Giancarlo, if you can say a few words on what you get from each time. Okay, basically, as I told you in a big or second, the idea is to make some sort of appropriately defined a scallop product between the signal and the model. And you have a very large number of candidates vector that you can use to make this kind of scallop product. As a matter of fact, you use first a template bank to find in a fast way the best candidate. But after that, you enter in a different procedure which has the aim not only to fix the best, the best estimate for the parameter, but also to give the full joint probability distribution for the parameter. And this use an approach which is essentially based on bias and statistic in which you, essentially with a Monte Carlo, you generate a dynamics of proposal which is explore the space of the possible parameter with the correct weight and give you back the correct probability distribution. This is something relatively easy to do when the mass of the, to play call, for example, is not so large because you are a best structure at the scene with many cycle. And so it has a very good at the extinguished shape. But for the case of large masses you essentially see maybe a couple of cycle. And so it is more and more difficult to disentangle these for some generic effect of the noise. But anyway, this is the way in which we do it. Okay, so I guess we are running a bit late. So I think we can stop here. I tell the students if you have some more private or you are shy to ask questions, you can come afterwards to ask questions directly to the speakers. So let's thank the two speakers. Sorry, okay. Atish, you want to say something, please? No, no, there was a question from somebody, you know, student in Jordan and I don't know if you saw it in chat. But this was the one. Okay. What address? Okay. Both of them, okay. I think it's from the same student. Okay. It was, yeah. Two of them were from the same student. Okay. So no, I just want to say thank you very much. And I also think that apart from the science, we can also continue our discussion about this international year for basic sciences for sustainable development and other aspects of EGO and ICTP. Thank you. Thank you. Thank you again. Good. Adibu.