Okay. Okay, folks, we can probably start today with allies and friends on the topic and minorities.
Minorities. Our president is due to have that where you said his position before that mean
their undergraduate degree in Athens they at Stanford University introduced
interestingly enough first couple of issues at Stanford he was in my late seventies
and married and then relation although I just go to temptation oversaw the life
that wasn't too long ago very committed to UC Berkeley and not actually that
happens for a post and then went to a senior position at Stanford is that most
recently to get the completed appointments did a minor amenities very famous
Nobel for having really no thoughts at the forefront of young cerebral physics,
particularly thinking about new ways of investigating programmable physics,
new ways of detecting very light particles, new particles in various ways with atoms and clocks.
And that moved from a tree. And she kept us going baffled as to what was going on.
Oh, thank you, John. I should say it's great to be back.
I've actually spent a large part of my time as an and as a graduate student here in Oxford in the summer.
And I have very fond memories of Oxford, have great physics.
We did great physics here and it's good to be back.
Um, so, um, so you see the title of my talk, but before I go to the nitty gritty details and try to explain what the title means,
I would like to tell you or some of you remind you of another very interesting prospect.
In the next few years, we actually will be able to observe, directly observed gravitational wave radiation for the first time.
And actually we expect this to happen from two experiments. One is light go, which is a light in the foot ometer and the other is and works.
It looks for gravitational wave radiation of frequencies between ten hertz and a thousand hertz.
And the other the other is actually a astrophysical experiment which looks at the timing of pulsars.
And both of them are and looks at very low frequency gravitational wave radiation
frequencies that have periods of gravitational waves that are almost a year.
And both of them are in the kind of race against the clock with each other to
see which one is going to be the first experiment to see gravitational waves.
And of course, gravitational waves are very important because they're the missing piece of the general theory of relativity.
They are the ripples of spacetime that are created. If you have two very massive objects going around each other.
And in astrophysics, these are stars, black holes, super stellar mass black holes.
SuperMassive black holes. Um, they, they are spin to particles, so they are quadrupole radiation.
So you're seeing the little video, how the vehicle that causes spacetime to oscillate in these two different shapes.
This is a cross, an X plus, a cross polarisation and actually we already know that they're there.
So in the figure that you see to the left, this is the eye.
They they have already observe the increase in the period of a binary system to two pulsars going around each other as they fall towards it,
either because they lose energy due to gravitational wave radiation. The red dots, as you see, we have observed that now in several binary systems.
This, the first one that they've observed is this PSR B 1913 plus 56.
They started driving it in the 1950s then before going for 30 years.
The red dots are the measurement of the rotational period of the two objects around each other.
And the blue line is the real prediction, and you see how well they agree with each other.
So we know they have to be there. So again, so there is space time.
So if you take the way you detect them is you take if you had to 2 to 2 masses to the masses, the distance,
if you have a gravitational wave passing through them, the distance between the two masses will change.
And in light go the light interferometer. You measure the change in the distance by using lasers and for the pulsar timing array,
you use actually some of the best clocks that we have in the universe.
Pulsars. They are frequency stability competes the ones with atomic clocks that can be better than one part in ten to the 15.
And we look at the difference in the arrival times, the variation,
the arrival time of the pulses from distance pulses within the local or local neighbourhood of the of the universe.
And besides the fact that we will complete the theory of general relativity, we will also have new eyes to the universe we will start seeing.
So given that they look at these two experiments, like going to look at different frequencies,
we will see different properties of astrophysical objects in the universe like for example,
is very sensitive to stellar mass objects that have roughly the mass of our sun coalescing and falling towards each other.
While the PDA, the pulsar timing array, is more sensitive to the in spite of supermassive black holes,
the holes the black holes that that in the centre of galaxies.
And the great thing about this is that hopefully in five years or ten years,
we will have a similar picture of the universe of our galaxy that we have in the optical.
So this is a picture of of how the middle way looks at different frequency bands starting from the from radio waves all the way down to gamma rays.
And we have different information come from that. So it's very exciting.
Uh uh, so.
And of course, we know there is a lot to learn besides learning many things about, um, a,
about astrophysical properties and properties of black holes, neutron stars and the dynamics in our galaxy, in our galaxies, in the universe.
We'll also learn new things about beyond the standard model of physics.
So this this axis here summarises what we already know about in terms of length scales, what we already know about our world.
So this big scale that we know is the Hubble scale.
It's ten to the it's the size of our universe, ten to the 26 metres, the smaller scale that we know of.
But there should be new physics is the Planck skill set by gravity.
And these are six orders of magnitude apart, somewhere in the middle of this axis.
Somehow, by coincidence, maybe we don't know that the dark energy, energy scale suits and which actually the dark energy, 65% of our universe.
And we also have probably by coincidence also the neutrino mass goes up around there that on terms of minus three,
if you go higher in energy, you start seeing that the standard model particles that we know of,
the three families of leptons and quarks, along with the fundamental interactions,
occupy some five orders of magnitude, starting from 500 k v for the air for the electron.
And the LHC is pushing us toward higher energies.
Now, if you sum up, if you in a large scale how much what we have observed this, you see that it only covers 80% of this energy scale.
So there's a lot of things to learn and to explore.
And as I've already said, there are already things to learn in the standard model because we have not observed gravitational radiation.
We have not observed another thing that we know is there in the standard model,
the cosmic neutrino background, which will have which will carry information about physics.
That happened one second when the universe was one second.
Of course, this is great, but it only accounts 5% for the known of the unknown energy budget of the universe.
The rest, 95% has to be covered by what we know seems to be dark matter, which is 25%.
Then the rest has to be covered by dark energy. And in string theory, one of the conditions to try to explain all of these string theory.
You also have a few particles that come with our efforts to explain these dynamics, like axioms that photons, that sectors delight.
On July, you may have heard all this. All this work has been thrown around.
And this is something else that motivates expanding our search in this huge energy range that we know is there.
So so this is so far putting everything in perspective.
But for the rest of the talk, I will focus on one particle alone.
And that is what particle physics a physicist knows that you should.
The axiom capacity stands for quantum thermodynamics.
It is the force. It's the strong interactions.
It's the force that holds the nuclei together. It's derived from the world, from the Greek word Kurama, which is the Greek word for cholera.
This is what we call the charge of the strong interactions.
And this is what the charged quarks kind of its strong charge.
Turns out that even in the standard model, strong interactions can introduce large violation of the charge.
Part of the symmetry a charge a charge conjugation is the symmetry that takes that the changes positive to negative charges and vice versa.
But these are symmetry that the symmetry. Symmetry. It takes it takes you from X to minus x.
So the standard model turns out by allowed by all symmetries that we know in the Lagrangian, you can write down it.
What looks like a base is the DOT product between the electric feel of the strong interactions, times,
the magnetic field of the strong interactions and the way the the magnetic field is captured while the electric field, the CP.
Even so, this term is something that mixes Scipio and CP even quantities,
so it could be violating its effects of parameter rise by the Greek letter seta.
It's called activity feedback. You see the angle and what this article does.
It introduces an electric dipole moment for the neutral.
So of course, the neutral by its name means neutral.
But it doesn't mean that the charge over quarks, the concept that the charge of the quarks that constitute it is uniformly distributed over its size.
So we're not totally expecting this parameter, given that what we know about the standard model, if we expected the parameter to be order one,
meaning we expect to be the ETM, the electric dipole moment of the neutron to be of order, the charge times the size of the neutron.
But we've looked for it for many, many years.
Even back in the seventies they were looking for it and we found that we found nothing.
All we've done so far is try to constrain this parameter to be less than ten to the minus ten.
Even back in the in the seventies, this parameter was was constrain to be less than ten to the minus eight.
So people wondered how do we solve the problem, a parameter that naturally we want to be put to one.
We find it to be tiny and several. This was back to below one.
So beton quy, along with the help of Weinberg and Franklin, checks Steve Weinberg and Frank Wiltshire.
I said, Look, let's make this accidental dynamic fulfilled. And we called it Frank, called it reaction out of a detergent brand.
He didn't have a good reason. We couldn't find a better name for it.
And this action of it's the dynamic of food, its cosmic evolution dynamically relaxes this parameter to zero this off.
So we know. So these properties of the action of this particle are well known.
We can calculate them very well. We can calculate the mass and get from strong interaction corrections,
from corrections from UCD and its parameters and its properties can be characterised by only one parameter.
What you may hear me say during the talk axiom decay constant, and this is one continuous parameters that varies across the energies.
And for a certain choice of this part, this part, for certain charge of this part of this particle is very, very light.
Its constant wavelength is three kilometres.
So if you compare it to what it is for the if you take the size of the proton, for example, it's one centimetre.
So compared to the size of the proton, this is ten to the 18 times larger.
So it's a very big particle, much bigger than the size of this, almost the size of Oxford.
This is this downtown Oxford. So if you look at the particle data group and you look for actions and you see when when they summarise its properties,
you will see a figure like this one axis,
the action f, the action decay constant which characterises its interaction, strength and the measured in units of electron volts.
And behind this parameter goes in giga electron volts.
The bigger it gets, the more weakly the interaction of the action becomes.
At the same time, this parameter, uniquely, as I said before, uniquely determines the mass or the quantum wavelength of the particle.
Which can be as small as tens of microns or as large as thousands of kilometres.
And for the rest of the dog, I will only talk about the oxygen mask and the Compton wavelength.
So given that this idea is 30 years old, people have again have studied this particle and they know that it is also an
excellent dark matter candidate for a certain part of its parameter space.
Um, we've, we've looked for it, trying to find it in stages, but they didn't find it.
And by looking at constraints come from a stark ruling, we find that its Compton wavelength has to be given roughly 30 microns.
We've designed experiments to look for it. You may have heard cast people, as I saw, even at 100 people have looked for axioms.
The first experiment to really probe the action parameter space outside too of what it is already constrained by.
Astrophysics is an experiment at Washington University,
at the University of Washington in Seattle called the Atom X and will probe this factor of roughly 100th in the oxygen parameter space.
So. What I'll be talking today is about the process that probes the action in a part of its parameter space,
where there's no current experiment that looks for it looking for it there.
What I'm going to be talking about the actual wavelengths between 300 metres and 300 kilometres and the process that's
involved in looking for this is super irradiance and in particular super radiance for astrophysical black holes.
And the reason black holes are relevant is because of their size.
So if you look at the size of astrophysical black holes, in particular black holes that come from the collapse of stars,
you see that the size is roughly 15 kilometres for a certain solar mass.
So that black hole, there are billions of them in the galaxy.
Somewhere between 100 million and a billion in the galaxy alone.
And they match the size matches the gives you the action for a certain part of its parameter space effects to measure the muscle.
If if you measure the mass in the vs between ten to the -1310 to March 11, if we similarly couldn't imagine using supermassive black holes.
Now they look for even lighter particles with much bigger wavelengths.
Who's. Who's? Now we're talking about Compton, wavelengths of 24 seven kilometres approaching.
If this is actually this one is close to the way to earth.
Some distance. So now I'm going to tell you what black holes.
But I didn't actually is and how how black holes can be turned into particle detectors.
And so this was super ideas that I've been throwing around is has been known to people doing general relativity since the mid sixties.
It's also known as the Penrose process, and it's a process that extracts energy and angular momentum from the black hole.
So if now I'm looking for that, let's say you have a spinning black hole.
And if you look at it from the top there, you have the rotating black hole in the middle with the horizon.
And there's a region around it called the region. This is a very special region.
What even like has to rotate? So if you take now.
So what is the operator so prepared? And electromagnetic pulse.
And you prepare an electromagnetic pulse in such a way that it takes the trajectory that takes it to their origin,
but of course, not to the horizon of the black hole. And you see that it comes out with higher amplitude than what it came in.
So in this process, the response has managed to increase its energy by extracting some of the mass energy.
That means energy of the black hole and its angular momentum. A blessing to Gorski had the following amusing idea.
They said, okay, let's repeat the same experiment and we take now.
But at the same time now we take a perfectly spectacle mirror to put it around the black hole.
In that case, what will happen is the electromagnetic pulse will start scattering.
Oh, yeah. So we'll start gathering back and forth from here,
go back to the mirror and eventually something that will start growing exponentially and the media will explode due to the huge radiation pressure.
This is what they call super irradiance instability. And, um, and of course, I mean, you can imagine, okay, how do we realise this in a lab?
I mean, we cannot make this perfectly circle metre, but it turns out what's to care about.
Super identical of course, is having a bowser. And in particular if you have a massive boson,
its mass will act like a mirror because now the massive bosom can create a bound state
with a black hole that causes it to sit in the vicinity of black hole and leak.
So all its wave function begins slowly through the in the ergo region, extracting the energy and angular momentum from the black hole.
So those are the process is most efficient when the particle quantum wavelength is comparable to the black hole size.
So now what you would expect to happen if you have a Nazi on or any bozo and a black hole that fits all five parameters much the right way.
What you will see is the black hole start to spinning down and then you get this cloud of particles rotating around the black hole.
Eventually the black hole, you spin down enough and the cloud will stop growing.
This is. Oh, so this is what will happen.
This is how you expect the accident from the existence of this cloud.
So how does this cloud look like? Well, you see the very close to the black hole.
You know what the potential is like. It's a mass because in one overarching Newtonian potential, it's not very special.
So when you try to solve what the bound states looks like, they look like hydrogen wave functions.
So what you have is a gravitational atom in the sky. So the fine.
So again, you can define now you can describe its properties of the state very well.
But just you have the fine structure constant, which determines the strength of the interaction between the black hole mass and the oxygen.
So it's the product of Newton's constant times, the black hole masters,
the action mass and the properties of each state can be described by three quantum numbers,
the principal quantum number, and which of them is the energy of the energy level, the orbital quantum number?
L Which is of course, the angular momentum and the magnetic quantum number and which is the projection of the angular momentum in the Z direction.
And if you calculate what the energy binding energy is, of course, you find similar things to what you find for there for the hydrogen atoms,
just alpha squared times the mass of the particle instead of the mass of the electron over ten squared.
But n is the principal quantum number. So of course, though, there's one main difference with a hydrogen atom,
instead of fermions occupying these energy levels, you have actions and actions at bottom.
So instead of maximally two particles at each level, you can have ten of the 75.
So you have this entire so this is a very classical. So it's like having a Bose-Einstein condensate rotating around the black hole.
Um, so, uh, which levels can cause this?
The question is, um, there's out so I'll go through slowly here there is out a super radiance is a kinematic condition.
So it happens not the level comes, but at the actually most levels if you have, if you put any action in in one of those levels,
what we will see most of the time is that the action falls back into the black hole.
It doesn't want to do anything, just be absorbed by the horizon of the black hole.
The special ones are the ones for which the total energy of the action in this bound state,
which is the action mass plus the binding energy, has to be less than the product of the magnetic and quantum number of a state times.
This quantity Omega plus, which has a weird formula, depends of the spin of the black hole.
But you can think about it as the angular rotational velocity of the black hole.
Um, so, uh. So this is, uh.
This sounds a bit magical. The best way.
The best understanding I found to explain what this cinematic condition is, is in some beautiful papers by their dovish and Bacons type.
So sporadic. So they they.
These are papers that were written in the seventies.
But that's really the first version of Super Radiance that was ever put down in literature is called inertial motions,
parabens or else cherenkov radiation. So what happens in Chekhov radiation.
And this is probably something that you've all seen pictures, the blue light coming out of reactors.
So in that case, you have a very energetic, very,
very fast moving particle that goes through a medium with a speed that's higher than the speed of light in the medium.
When this condition is satisfied,
the particle starts emitting spontaneously and we think ahead of the dish and turns out it's picked up a UAV for the electron.
So that's why you get the blue light. So this is for linear motion.
You get actually an analogous effect when you have rotation.
So now what you have is a cylinder less like a cylinder.
It doesn't have to be. And you can think of a black hole, take a picture of a black hole as a cylinder.
And now you, Scott, think it's got that from the cylinder and the electromagnetic wave,
which because you're talking about rotation now you you call the compose in you have E to the
Iomega T minus from five because you're decomposing as a muscle in a num car in momentum,
in angular momentum, I get functions. And now the requirement is that the object that does the rotation moves faster than
the it has angular velocity that is faster than the angular phase velocity of light.
Um, uh, in particular. Actually, there is another example.
If you have the, you can even imagine this for a particle. If you have a cylinder and you want to scatter a particle tangentially from the cylinder
in order for the particle to come out with a higher velocity than what it came in,
it has to come out, come in tangential it with slightly less linear velocity than, than the rotational velocity of the cylinder.
So, uh, uh, so I'm trying to spit out this is not very special.
It has nothing to do with strong gravity. You can imagine you can design systems in the lab with just electromagnetic interactions
with separate things can occur and people have indeed tried to do experiments on this.
Um, the other important parameter is the rate of growth for radians.
So people have calculated this, uh, it's basically, it has to do with wave function overlap.
How much the wave function of the action within the ball state overlaps with the ergo region.
And we find that the fastest we can be is ten to the seven times the full time to the black hole the size of the black hole in.
Uh, uh, so if you convert this to seconds for a one Solomon's Black Hole, this is 100 seconds.
And if you compare it to the two, for example, if you if you want to know what does it mean for astrophysics?
The dynamical evolution timescale for black holes, which is called the electron accretion rate,
is how fast black holes accrete each stuff and grow is ten to the eight years.
So four astrophysical black holes. So you have 400 seconds compared to 10 to 8 years.
So for astrophysical black holes, turns out even though this effect naively seems small, it has a lot of time to grow and affect their properties.
The properties of astrophysical, black hot. And again,
we have the like a coincidence that for stellar mass black holes this size can match the Compton wavelength of the gas should the oxygen for a decade.
Constance that that around the Planck scale.
So this is this is a slide that summarises what I've told you so far.
So Supernatants actually has nothing to do with gravity.
It's just a purely kinematic effect. You can design systems in the event in the lab where this happens.
There's out. You need to move very fast because it's still a super luminosity condition of some sort.
So black holes are great because they spin very fast and they have very strong gravity.
And the other thing that black holes do, because exactly. They have very strong gravity.
They're very good vacuum cleaners. So they can clean the environment well enough so that any gravitational potential
perturbation around the black hole does not perturb the potential of the state.
It does not cause it to fall back to black hole.
So to see how this effect, how this effect evolves for us, the physical system for it,
for a realistic astrophysical black hole, what you need to know is, of course, how fast does the instability grow?
How does it how fast is the sequential growth happens? What is the dynamical scale of black, of the evolution of the black hole,
which I've already told you is said by the accretion rate, which is roughly ten to the eight years.
I won't go into this detail, but there's something interesting that can happen when you have oxygen safe interactions,
when you have oxygen safe interactions. They can affect the evolution of the.
Of of the effect. So when the energy due to self interactions in this huge cloud of ten to the 75
actions becomes comparable to the binding energy of the state of the black hole.
The cloud collapses.
And you actually get the very, very, very spectacular effect that they've actually observed for real Bose-Einstein condensates in the lab.
And it's called the Bossa Nova Effect, taken from, uh, uh, the, um, the similar name for the astrophysical instability of stars.
Um, now signals, what do signals how would we know that this actually happened?
So given that I've been talking about atom and hydrogen wave functions, the first thing you would expect is transitions.
You have this gravitation of atoms, so you expect the transitions of actions between different levels of this atom
and simultaneous admission of gravitational wave radiation because of reactions.
These are bosons that occupy exactly the same state. So you get a gravitational wave laser.
So what you get out of this process is a very monochromatic signal whose strength is enhanced by the product of the occupation.
Number of these two sets.
Another similarity monochromatic process that is not you may not be very familiar with is action in relation to one graviton.
And this happens because gravitons are particles. If they are, they are only particles.
So in fact, two axioms can relate to grab atoms.
But what happens now? Because you have the black hole, one graviton gets falls back into the black hole and you only get one coming out.
So this actually has been observed. A similar effect has been observed for the atom, the positron.
So you can take positrons and throw them towards electrons with are bound to atoms.
And what happens in the case of spin out of the positron annihilate in two photons, you select them positrons and you get into only one photon.
Because now the photons that were supposed to come out get absorbed by the nucleus,
who got all the recoil to preserve energy and momentum in the process.
I'm. So let's let's follow now the history of spreads, huh?
So now let's start with the stellar mass black hole. This is a plot that shows in the in the Y axis.
You see, the parameter is that the parameter rises.
The spin of the black hole zero is a non spinning black hole spots a black hole.
One is extreme a black hole. It's the fastest it can be. Possibly spin, basically rotational velocity of one.
And on the on the x axis you can see the black hole mass masses in solar masses.
The black dot that you see there is a solar mass is a stellar mass black hole of over because of mass six solar masses.
Um, and we, we started with theta when it was first created after the supernova collapse,
you would get a black hole that has this mass and it's been that close to 3.95.
What is shaded now in blue is the different super advanced level.
And for a given action of mass of tens of -11,
which is a Compton wavelength of roughly three kilometres and this is this this black dot sits in the region.
What it would be affected by to produce. So what happens?
Uh, since it is affected by Irradiance and in this case, the one that's relevant for separate things is the equal to level.
The equal status to level starts growing. And for these parameters, it takes roughly two years to grow.
At that point. At some point, the the the black hole loses so much pain that the level no longer satisfies the sporadic condition.
And you stop growing and you get stuck along this line that because it's a relation between what has been called the trajectory.
Then there is out for reasons that I don't have time to explain.
The blood clot stays there for roughly ten to the six years for about a million years before the next level starts.
It starts starts growing and then the next level starts growing and you fall down again in Spain.
Oh. And this time we fix it for a longer time. They extend to the four years for this process to happen.
At some point you stop growing, but there is no longer a focus.
But I call because the rate for the next, for the timescale,
for the next level to grow is bigger than the Eddington accretion rate or the age of the universe.
So the black hole is no longer affected by sporadic.
The reason, by the way, that you go vertically in the mass and this whole process, you lose a lot of speed, but not a lot of mass.
The reason is that the cloud is much bigger than the black hole.
So you have the ballerina effect. So you can carry a lot of angular momentum without having to carry too much mass.
So that's why it moves vertically across this plot.
The interesting thing is that actually what I've drawn here is that is a realistic situation because we can learn something from it.
So if we had an action that has a quantum wavelength, for example, three kilometres here,
it would have effective all of black holes, all of stellar mass black holes in the in the universe that were sitting in the blue.
And you should have no black holes in the blue region.
And all the black holes should be concentrated in the white region. And we've actually done measurements.
People have actually started measuring and this has been going on for 15, almost 30 years now.
People have measured in spins and masses of both stellar mass and supermassive black holes.
And this is actual data.
So this, again, a plot that shows the black hole spin is a function of black hole mass.
And we've drawn here for a roughly one kilometre sized action.
And you see that that action do you see that red point up there that actually this now this measurement excludes the action that's plotted here.
So you can actually put constraints. And we've done that.
And you can make plots that look like this.
So on the horizontal axis you put, you can do it separately for stellar and supermassive and supermassive black holes.
So on the top, right, you see what you learn from stellar mass black holes.
One axis is the action mass or the action quantum wavelength.
The other axis is the action solely for interaction.
At some point as you go up into the Y axis, the action.
So that actually becomes stronger and stronger. And at some point it inhibits the growth of.
And so you don't get a fixed for a superior view.
And this is for a similar for supermassive black holes. So this is actually the first ever constraint,
what appears to be the first ever constraint for the use of the action that part of the of parameter space.
And this has happened like 30 years after it was first proposed. So now let's go to.
So, of course, these exclusions. This is not very interesting, but let's talk about signatures.
Again, as I told you, this is a gravitational atom.
And turns out for this gravitational atom, the you can have levels that have the same angular momentum kind of numbers,
but different principal quantum numbers that can be occupied by large number of accidents at the same time.
And you can have transitions of oxygen for stellar mass black holes.
The transitions appear at frequency at anywhere from 15 to 150 hertz for the
Q should the action which is the optimal frequency band for advanced legal.
As I told you, the signal is enhanced.
It's like a losing effects of the signal is enhanced by the by the occupation number, by the product number of the two levels.
You bet. If this also determines the signal strength, this h you don't worry about this formula.
I should have removed it. And the signal loss can last from anywhere from one here to 100 years.
Um, so we took, um, so people have done feats of the distribution of the, they've,
they've done feat by, by measurements of the distribution of black hole masses,
black holes spins as well as the black hole distribution stellar mass black hole distribution in our galaxy.
So we can take those distributions. I take into account the birth rate of black holes and estimate how many, given the sensitivity of advanced LEGO,
how many black holes will advance like you'll be able to observe going through the sporadic process while the experiment is running.
And we took as they do for when they calculate event rates for uh, for inspired us we took a pessimistic,
realistic and optimistic assumptions and we get this plot from the bottom, right?
So this is the number of expected events as a function of the actual mass.
And what you see here, of course, given the loss, as you see, the first thing you see, astrophysical uncertainties are huge.
You can get something that's event rates that go from depending on the action must have zero from 1 to 10 to the minus three.
So this signal is a bit probably a bit tough to see in advance, like, oh, these are not very they couldn't be better.
They could also be worse.
So and what you cannot see actually in grey of this plot doesn't show very well what is already excluded by spin measurement.
The most promising, though, signature for the.
Four four for observing actions of advance legal is action in relations.
So you think, as I told you, this is a process that takes two actions and produces one graviton.
The frequency, the energy of the action of the graviton is twice the action muscles, the direct measurement of the action mass here.
And the frequency appears at very high frequency for the gives you the actions for these parameters of the
drums can be above kilohertz around the kilohertz again because this action sit exactly on the same state.
This is a process that the hands by the occupation, by the number of above, by the number of actions the signal person has,
but the number of actions quit in the cloud so you can get something reasonable.
This signal actually, because this process turns out is much slower than transitions, the signal can last up to thousands of years.
And this is good because.
It makes our signal observable, more easily observable at the vast library.
So again, we took the same assumptions for the distribution of black holes.
PS Masses you cannot really see.
Is it a pointer? That should be. Yeah.
Here. Uh. Let's see here.
Okay, so here is what is excluded. This grey band. Here is what they excluded currently by black hole spin measurements.
This is the actual mass here. And now you see that the event rates have gone precipitously up.
You can imagine the owners get thousands, more than thousands of events, if there is an axiom there.
And if the right must care, this corresponds actually to actually the conference around the Planck scale,
which is actually it's a well-motivated scale. And you see that advance, like what could be it could be turning on and see thousands of events.
That means thousands of black holes have an oxygen cloud around them, producing monochromatic gravitational wave radiation.
So, of course, though, as you can see, again,
there is huge uncertainties that have to do with black hole distribution and black hole spin distributions in our galaxy.
Nevertheless, this is extremely interesting.
Uh, and so, uh, so and so I've, we've, we are in touch with like people and they seem to be very excited about it.
Um, so this is a blog that summarises what I have told you.
So black holes turns out. Ah, a have provided us with a natural detector of this of a large wavelength particles, black holes.
But I think it's a process that has been known for a long time and it can be used for can turn black holes into particle detectors and probes,
a very well-motivated particle,
a particle that could be the dark matter of the universe in a part of its parameter space that is not probed by any run experiment.
There are several. There is only one proposal that probes a similar part of the action parameter space,
but that also assumes that the reactions that come out so black holes operatives does not care if the particle is any component of dark matter.
It will happen if the particle has a gravitational copy and that's it.
Um, so and I and as we estimate, it turns out that advanced light, which is about to turn on is about to start in a few years,
will be sensitive in a part of the parameter space where there are currently no other constraints.
And this will come just from astrophysics and because of irradiance, not because just in and because of that identity kinematic effect.
And all you care about is your particle boson. Those are audience is a process that will be sensitive to any light particle that
is a boson and has a constant wavelength larger than a thousand kilometres,
naturally kilometres. So. Thank you.