I'm not jotty, you may have noticed, but yeah, they are away at the moment, so it's myself and Deborah hosting today. We are very lucky to have Ben with us. Ben's an associate professor at the University of Plymouth in theoretical physics and is working on laser particle stuff and is here to talk to us today about that
So yeah, over to you. Hi, everybody. Thanks to the organizers for inviting me here. Although I've been kind of associated with the Central Asia facility for a long time, the theories I've never actually been around before, because it's very exciting to me
So, I'm going to talk about science goals and laser particle interaction. So this is a bit of a synergy between particle physics and physics. And I noticed, we just sit in the cafe
The cafe sits between the particle physics building, which is attached to the central laser facility.
This is the perfect place to begin this kind of a talk.
Okay, so we begin with some sort of kind of some key concepts in strong field electrodynamics. That's going to be the fundamental theory that's going to describe what's happening in those interactions between charges and wave forces
And then we spent a little bit of time talking about charge field coupling in Tensor electronic backgrounds. I think that's something kind of unique to mathematical pivoted before, so it might be interesting
And then the second half, a little bit about kind of
Measurements that you want to make at different experiments and science schools of these things. And then finally talk about the Hp
Okay, so just going with some basics then. So we have the scattering paradigm in particle physics of having two bunches of particles in our instate, which is well-defined and understood
We collide them, and we infer from measurements of the skeptical particles that physics that occur during that expansion
Now, before we consider is our dying where we replace one of the themes of particles with an intense laser pulse. So we have a probe beam, the electrons or positrons are completely photons, and we have an intense laser
Now we should perform the same kind of scattering experiments where we tend to measure is what happens to the protein
And so from that coordinate collision has the charges propagated in the X
Different to the public normally tend to measure what happens to the laser force because with this in high intensities, high intensity laser pulses are highly focused, which means that the shock-to-shock reproducibility is quite low. Instead, it's maybe the protein at the low
It's slightly different, but there's some kind of similar to
So, talked about intense electromagnetic fields by saying that, electromagnetic field is intense. I'm intrinsically saying that the field is coherent
So interesting coherence electromagnetic fields are quite important. So some examples are slowly varying magnetic fields, so in cavity experiments, PV mass or ELFs. The fields inside are crystals with a high degree of symmetry
Well, in that case, you've essentially got lots of Coulomb centers, but if you have a charge which is colliding with that, all those Coulomb centers in the rest frame, the charge appear as a coherence field.
So for the QD, I'll talk about can we use describe bacter physics. Beam scattering. So beam strolling, apply particle energy is an example of a magnetic field. And what I'll talk about mainly from this laser pulses. So this could be optical laser pulses or X-ray electrical lasers
Coherence implies that the average expectation value of the electric field is 0. A count, for example, would be incoherent fields like blackbody radiation and strong or radiant dust jets where there's not a well-defined phase relationship between photons with these are different
So incoherent fields like this, we expect that the
The expected field strength is operation is up to 0.
So I mentioned strong field, what do we mean by strong fields? We can come up with a QED field strength scale by taking some of the fundamental parameters from QED. So the electron mass, the positive charge
Thanks, Custom. Put them all together using dimension analysis to come up with a field strength, and you get this formula here.
So this is sometimes referred to as the Schringer limits or crystal clear. These are really bad names, because first of all, it wasn't Schringer who first came up with this more than a decades before. I didn't know what we're talking about. This technique's not lit. As you can see, we can go beyond this critical theory is also a bad name. There's no crystal phase transition that happens here
But people use these names, so I'm going to refer to them. But the field strength as the strength level
What's the kind of physics that can occur in a field of this strength? Imagine you've got a constant homogeneous electric field of this strength.
You can work out the, work done by the sealed home and electron, same as yield
They charge the electron, fuel strength, and for the dimension of the electron, we take its quantum wavelength. And the work done by a few of we could make one that was this intense would be the rest energy of the electrons. We expect that when we have
Order will secure the effects like creation of electron
Can we see this in nature? We have this strong in astrophysics, it seems like we can. So this is just a plot from this review of strongly magnified neutron stars, and what magnetic field strength they have
So you can see from the top right there, the QED field strength scale, the Schwinger limit to the magnetic fields is around 10 to 13 Gauss, and we can see lots of data points beyond 10 to 13 Gauss compared to 10 to 14 to 15, which tends to be things like an almost electrical pulsars.
So in nature, we can
Albeit the magnetic field's not letting
Can we see in the lab? Fortunately, with high power lasers, we're not quite at the level where we can produce these label about three orders of magnitude away from machine learnings with lasers
So why are we talking about QED with lasers? Well, we use a standard trick, which is we consider gliding charges like electrons or positrons with a laser.
Then, in the rest frame of those charges, the field seen is lines boosted, like the L factor
So the faster the electron is that you can write the laser, the larger the field strength in the rest frame. And this is just a nice cartoon from
From Jackson, this is, the cool field lines on an isolated charge, and this is what happened to any Lorenzo in the horizontal direction. You have a bunching up the field lines that indicate the enhancement of the industry
So how do we quantify this? I'm going to introduce a parameter chi to occur quite a lot in the talk. So spend some time defining it properly. So chi is the strong field parameter.
It's just a projection of the virtual momentum on the field strength tensor normalized by the rest energy and the unique field strength scale.
So what does that mean physically? Well, if we choose our fields, our background field to be a plane wave, and we're going to be interested in lasers so it makes sense to model a lasers and a plane wave
Now, in this parameter is exactly the field seen in an electron rest frame in units of that strong limits
So
We can again say, I want those physics does I occur to? What does that correspond to? We calculate the work done by this plane over here in the respiratory electron. And what we get is that this is chi times MC squared. So obviously, when chi is order one.
That reason we call it.
So getting to try order one experiment would be great. I'd be kind of take the odds and later part of the experiment
There are suggestions for getting into much higher values of the software parameter
I'll just give an example. So this is our URL a few years ago where they did a simulation of beam scrolling for two cervical electron beams colliding with 125 Gb, and from their simulation, you can see here on the right, these regions of
Red correspond to chi which as we'll see later in the talk is a significant part of it.
So, next-generation linear colliders
strong acute effects or whatever process you want to study
Okay, so that's a little bit about what we mean by strong fields. I want to talk a little bit about the interaction between a charge and a laser
I'm going to specify for a plane wave just because it's easier to explain.
So, this is a little bit theory. Hopefully it's
So this is the gate potential for the background.
All right, so it's the only important thing is sorry. So energy electron mass is the organizational background. This is just the shape of the laser pulse. Psi is something called the intensity character. The more intensity the laser pulse is the higher the magnific
So what is… sorry, what's it correspond to physically
So we consider a standard QD process. I picked up the example of a photon flying with a laser to use electron positron pair
I only can calculate the interaction of the pair with background with the laser
For example, Bobby, one interaction with the laser represented by dashed lines, or having two interactions with the laser and interactions, etc. We find that the amplitude scales with excise the power n
That's kind of interesting because normally in QD vertices scales with the standard QV document charge
But here, that's being replaced with the laser intensity. So the more intense we make the laser, the stronger, in some ways, we're binding the electron protons to the laser force. So actually, it looks like maybe more intensity actually changing the nature of the
There are other ways to understand this parameter. If we would look at, yeah, processes
With N trucking to the laser. The probability scale is like this square, so I to n for nether photons, or in other words, psi squared to the power n
So what is psi squares? Well, we can write it in terms of alpha qed
Volumes are 3 volumes with the laser wavelength and the quantum wavelength, and a total number of density in the laser. So the very hand way the square of the intensity parameter
Is we find the number of interacting photons
So the more intelligent look later, the higher the number of photons in the laser interacting with the electron at any given time
In exchange we can make signal to one
perturbation series anymore. And you have to include all orders of interactions between the laser and the background. And so you would have this sum this
So we refer to this as a non-performative interaction between the laser and the charge. So this is a prediction of quantum field theory, which we can principal tests and experiments.
Something like the comparison with neural saturation with small geographs
The analogy is because they require the number of charge is getting photons, but essentially number of targets that the electron has when it interacts with laser force gets large
Yes, I mean, it's important calculations. We have to resolve this. And
So my background is as a theorist, I think most of your background is maybe an experiment or simulation. So I have one side of theories to explain how we do the calculation on one slide. But if you have any questions, then just drop me in.
So how do we do this
Well, we don't do it
He said, what we do is we we split our vector potential for the waves into two parts. For the vector into two parts
One part is a laser, it's gonna get classical yog, because the laser is close to being a coherent state. And the other part is the radiated field to an electron radiates photons, or maybe there's some loop effects to do with electromagnetic field. That's a quantized part
We take the standard version of QED. So it's the three parts. This is the three fields, the electromagnetic field. This is the three fermions, and this is the interaction. And now we split into two parts. We've got an interaction between
And between the elements and the quantized field of the radiation field
I would just rearrange this
Remove the introduction of the laser into the free particle theory, and the consequence of that is that the equation of motion that we have to solve for the electrical electrons, i.e. the Dirac equation, is modified
By placing the potential of the data inside the verification
And that's the thing I could solve for in order to introduce this interaction into laser tunnel
Now, we don't have many closed form solutions of the Dirk equation in a given background, but one of
We can solve for the recreation pool is plane life. Using the plane wave to have to model a laser. You might argue that a laser focus laser isn't a plane wave. That's right. But we're going to use these solutions in a circular realm that we want to describe
Okay, so the leading process that we have is just that single vertex. This is an example not content scattering. The lecture comes in, collides with the laser, produces a hard
The double line represents the part that we're using this solution to the equation of the plane wave. These are all costs, it's a Volkov, the Volkov electron
And if we wanted to, we could expand this double line in interactions with the laser and look at what happened to it
What interaction related to interactions related, etc. But we don't typically do that because first of all kinds of water, so we need wall orders, and secondly, we have the all order solution. So there's no reason to objectively fund it
So this is normal content scattering
It might seem strange that the leading order process is this throughput function. So normally in QED
I'm also like this is kinematically is one of the two vertices here because we've got a laser field interacting with the electrons
That's able to donate energy, momentum or absorb energy momentum from this interaction. So that changes the usual kinematics. So that means there's a regional phase space where this collagen
That's why legal order process is just a single vertex
So this is not encounter scattering. We already saw pegation
I've become there. So we may even use the word nonlinear to describe these to differentiate them from all standard QED processes because of the nonlinear interaction between the laser background and the charge
Before we also have at least proposes like one photo annihilation or photo adsorption, but we don't tend to
Okay, mainly because it's difficult in a laser port to bring electrolyte photon, and the outgoing phase space was smaller for these
So typically, these are the ones most interesting experiment.
We also have signals from loop processes, like, mass operator, you can use your QED. It just contributes to the mass renormalization of the electron. But now people
the laser there this experimental signal. So one of the signals of this this interaction, for example, is the spin of the electrons as it collides with the laser flip in a non-radiated way. So there's no virtual photon here, slipping flip. That's something
who measured in experiments, polarization operator, another example of a loop process where we have an experimental signal here and signal price similar. So it's a photon interacting with a virtual electron positron pair, which is polarized by the laser. The signal there is a change of the polarization of the photon
So it might have a vacuum biorefringent, that's essentially the process that they're trying to measure in experiments like to be that sort of high therefore helps. And then we have a matrix operator, which is less well studied because it's got three vertices, so it's a higher order.
But principle, we do have some
Okay, so that's a little bit about the background. I wanted to talk a bit about what people are looking for in experiments, because I think that's more accessible
So two experiments refer to the texture again, experiments are going to differentiate themselves by a different source for the strong field or a different source for the high field. So the strong field
Sorry for high-pile facilities
my optical focus beam, so energies of a few EV at the interaction point.
strong fields
Studies around kev, poly to crystals. So the Na63 experiment 7, for example, takes the electrons from all the SDS, lies them over into crystals, and they enter crystalline field there actively known field
Also, Google fields. So splitting of photons in Coulomb fields or the change, the scaffolding of photons in Coulomb fields
As an example being so long, we talked about as well, and such a visual context. So that's kind of the different strong fields that we could consider. In terms of the pro beams
Doing experiments at high-mile facilities, you want to have some vascular beam. Unfortunately, typically a Linac is not co-located with that mobile laser facility, so acceleration of electrons needs to happen on the surface. And so that's normally done by laser weight cube acceleration
Josh Jets.
That's our electron probe, a photon probe, you might combine them with a target to give a restore on sort of photons, or use a secondary week later to produce quantum scattered source or use crystal, or even thermal emission
If you've not seen that, well, if you've seen Laserpoint before, you have definitely seen a plot like this. Every laser podcast I have one in, which is explaining why people are interested in using lasers to produce the sound field. So on the horizontal axis, we've got the decades
And then the vertical axis, we've got the maximum intensity produced in a laser in that decade. So obviously lasers were invented around the 1960s and various inventions have allowed to get to higher intensities, higher intensities allow us
More and more of these lasers. OPCPA was the innovation that led to the Nobel Prize in 2018. And this part is actually slightly outdated now, but there'll be other data points here. So the point is that
What the investment is going into high-partless facility because to be able to reach high intensity allows to do more interesting experiments. And so I was trying to make the argument in talks like this that high-powered facilities are a great place to do fundamental physics
Okay, this is another thought, which is similar, different laying facilities by decade. The only thing I want to point out here is the most recent laser facilities around here are accessing intensities where QED is the dominant effect in experiments. So we've
Dynamics which are dominated by visual pathodes. Here we've got avalanche type cascades, acutely cascades producing photons at all these pairs.
Okay, I want to give an example of all optical experiment before I talk about particle physics side of things. And I realized being here, I should really have talked about Gemini since it's not very far away, but when I made slides different later. So
If you're doing that.
The, one example of the whole experiment is a recent start at the facility, the Center for Relative Laser Science in Gangzhou in South Korea
So this is kind of typical setup. You have your main laser beam collides with a gas jet or a gas cell to ionize particles to liberate electrons, which are then accelerated by acceleration apart from that main beam being is then peeled
I refocused the interruption point
The acceleration
And so here, this is the gliding laser, this is the tane wave that was on the previous slides, and you have the electron beam being coming in, and this is… in this case, they measured nonlinear Compton scattering. They matched the electron being downstream using Linac screens
And they separate products for the reaction using magnets and later for the photons they need to iso screen, which is a bit like acting like a
This is an example of a laser matriot accelerated spectrum. So typically it has a narrow peak at energet
Which is, of course, very good. The problem is there's quite a tail here, so the if you want to do anything with precision with laser weight, you have to take into account the fact that you've got this long tail, and that's not just a matter of force
The advantage of using lighter weight acceleration is that you can do acceleration on a very small scale. So you don't say you don't need to do much.
Sorry, I should consider
But the short-to-shot reduce diversity is quite poor in general, although it's getting better. So if you want to build up statistics with collisions, it's difficult, said simply you choose collisions which
overlapped really well, and then you analyze those.
So the car was experimenting, they measured electron spectrum, so that's kind of the idea
So they've got agreement with pollution from QED, just by way of
referring to the premises, the intensity parameter 10 and the strong QED parameter is not one, but it's 0.1.3. I think the best that they got 0.4
So, it's spectrum down the tail of the agreement gets a little bit more detail.
This is some parameter space for different experiments among the Hampton scattering in the horizontal plexus, we've got the intensity parameter. So that's the charge field
The Creek towards the strong field towards the diagonal line, and we get to higher strong field effects that we get over here
Medical access is the energy parameter. So it's to do with the center of mass energy. It's only of the order about 0.1, 0.01 for these experiments
So you've got these series of experiments that are being performed for the lasers where you go into higher and higher nonlinearities, it's charge
And then various experiments, they're actually being commissioned or take notes, which will really push this to much higher values of the synthesis. So really looking at really highly nonlinear interactions of the background
In contrast, what are these experiments here. So these OC stock at the problem from the other side. They don't start with high power latency. They start with that
Then they use a moderatorizer in order to
What's that? Thank you for the slack and Luxies requires that phase and I'll talk a bit more about Luxy in a second
So they have the advantage that they can go to higher energy, but the sample rate is less so they can't probe this nonlinear function as much, but I'm going to make the argument that's fine
Also, because they're using a laptop, they've got narrow about source of electrons, so they can
Reproduction is good, so you can build sophisticated.
Just by way of interest, this kind of overlap between particle physics and laser physics, I think, is something that's attracting more and more people. Last year, we participated in this
Exercise run by certain every five years to solicit inputs to the European strategy for particle physics. We run for QED, such as things and
The heads of groups at different places in Europe, and we had some guest authors from outside of Europe some of these high powers, some of these countries. Laser physics is not quite as established, but particle physics, obviously laser emotions colliders
It's slowly starting to consolidate into larger and larger groups.
So I want to talk about this lips experiment because it's maybe more interesting for the particle side, but also UK is quite well represented. So look see stands for laser on axial experiment and it
That's right.
institutions from the Uk. We've got Manchester, and Plymouth. And the idea here is to use the electron beam that drives the EU Xfel. So that's a 16.5 Gb electron
And it's a similar kind of sound to what we saw in the Carlos experiment
It's just separate parts of the reaction and
Separate them from the hydrogen
What is an example of what I think this can bring to this field
And that's associated by this ugly photon spectrum in the quantum schedule
By having a Linac behind this, we have
Bush now programming, which means that we can measure what's happening in our scattered total spectrum to a higher precision just by a bit of statistics, but also by knowing what's the nature of the collision
Here's an example. So, this is a log plot of the number of photons produced by crossing of the electron beam, and the laser mostly
These are different intensity paraches
What we see is for site order one, we see a parbonic edge to do the edge of the first harmonic interaction with the laser. As we increase the intensity, this harmonic edge gets washed out and it's redshifted
I learn the values of precisely what I want, we see a very strong signal. By having a higher precision
Probing, we can measure the position of this edge, which is much better access to what's going on in the physics than just terms of yields.
The position of this content, as it's called, is in both formulas. It's basically just a fraction of the photon energy
By the natural attitude. So people have actually been with the electron energy sciences.
Each has this energy process, not so important point to
The interesting thing is where the intensity happens. Remember, the psi parameter is the charge for your cup
Which are comparative linear TV. Linear QD, we factor out positions where are eventually formula that's calculation
The presence of the laser is introducing these nonlinear corrections
As we increase the intensity parameter, we're picking up more than interaction with laser higher and higher order
So weight size of order one, then we can't truncate this series anymore
And it says we have to include this interaction to all audits. So measuring the position of this edge as we change the intensity uses an experimental probe into this all order interaction predicted by our computer theory
An interaction between the elections will be delays.
We could essentially say, oh, okay, let's not look at emotional community, let's look at the production of classical electrodynamics
They'll be more than a constant scattering
And then you can see the picture of the latest quality edge is of how it changes as we change the intensity. So it's a leading order, which is that here. I factorize how a factor of H bar from this ether parameter to show that as we change the intensity
We're picking up and becoming more and more quantum, if you like. And
So one of the things about this here is people really care about the difference between classical and quantum physics. So as you change intensity, you're in more and more quantum corrections
And so you can block whether content edges as you change it, what the energy is, as a function of f
If site is small, very, very small, it's just an issue. If psi is too large, as you can see, if psi is too large, it's just nonlinear classical physics. The interesting thing is happening around time orbit plane
prediction from standard linear community
So my message for stuff like this is we really want higher precision over power
Detroit's not really powerful methods at least, but using magnificent particle physics, higher precision
This allows us to actually have a much better probe of dictionary
So we have a measure electrolytic collisions. We also want to measure photonic collisions. So we do generate a photon beam electronizing an electron
being a solid target, there's rent strong ponds. Or you can also get off part of laser to have a confidence gathered source of photons, which has the advantage that we have quite a high polarization grade, which allows us to do more specific theory
We'll be at the cost that we have much lower energy. Also considering using a crystal radiator
structure target, essentially, gives us
kind of narrowbandish sorts of protons, achieve them, ICS source
So what's the signal for tokenized collision? So we've seen already is pair creation
So thinking about this process of tag creation is if you take a single laser protocol and you take the high energy photons that we produce from that source, the the mass energy is too low to create a pair
You have to answer quite a large number of license before you get to the threshold where you create a pair.
So if it looks like on the 11 protocols.
That means an alternative signal, leading order and lead signal. Scales with size of power 32.
The yield of pairs, the photons is colliding with the laser. If we just had
But doing all the QA with this this kind of
But as we increase psi, we have to include higher and higher orders because obviously this is a series of size model, including all orders. And the result of that is there's actually a suppression of pair creation
And this can have here, and this totally is the curve away from the interpretive but highly nonlinear prediction is our signal of all order interaction between the charts in the background.
albeit now. Figration, which is a fully quantum process
Okay, so even just reading all the processes, we also want to look at high order processes. For example, cotton showers, you can imagine your electron being close to the laser and more than one photon
Now, something's a bit different in interaction with laser pulses than possible beams. Pascal beams, if you have two energetic beams colliding from a rest frame of one beam, it looks like the other beam is relativistically pancake, right? Longitudinal
But here we go home with training focused, which doesn't run as a contract.
So the consequence of that is that the longitudinal scale of the lighter bolts allows for much higher order dimension
And if you consider a higher basis like this, the propagator has a virtual part and real parts
Just by the integrity relation with virtual power can't propagate very far
So that means that higher order processes like this are dominated by the propagated real. So here, for example, an electron making a photon renal propagates like a normal electron.
This is kind of a silent approximation that we use to calculate higher order processes
So here's just an example
This is for 8 of the electrons of scimetha, or we can have it, a bit lower than what energy we have, let's see. And this is using the Tarnigan open source simulation code, which is being developed by Tom Blackburn at the University of Gothenberg.
So we see is chi of two, time a naught used by different groups of people doing the same thing. Chi of 2 for electrons around
average, most expected thing to happen is that they don't make any changes in their life, basically
As we increase time, for example, 7.5, it's most likely that neutral electron emits an average declining
So even though the second order processing is more promptful than the leading order process, it still preservatively
However.
It's been a while that there's an exception to this. And this happens if we
Imagine that we have this length of the prompt set. Imagine we can make it really large
And what happens to these three-level processes like longer, is that in the large chi limit, they scale as ubiquity has taken over two-thirds.
Now, this is significant because you can ask the question, well, what if we could reduce I of order 1,000? We solve the process for doing that already in the lab. What would that mean about this unit fraction
Well, if I was in other countries, that's all the
What that means is that this kind of conservative series here is not something that we can pronate. We could have the situation where we could just say, oh, we just stop our 6 functions
Instead, we have such an intense backgrounds so large, that would mean we'd have to include all interaction, not just in the laser, but also all orders I measure
So somebody will say that QE
when we have such an intensity of
Now it's not just country level diagrams, it's also loops. So polisation operator and electron mass operators go like alpha chi
Typically, in calculations, we don't really include
Right at the corrections, because as we saw, things are dominated by things being real
So if we had other kinds of two-thirds, not only would we have to include them, but again, we'd have to completely
There's a nice series of experts in the 70s and 80s where they calculated leaves a higher order, domain with commuters and morality. And they go all the way up to three loop and they found that the divergence with Chi's strongest
Chains of organizational operations have reported
And so there's a conjecture called the Rocky conjecture that if we have a very intense field, so if the field is locally constant, and it's plain wave in nature
The true expansion of beauty is an opportunity, but it's held by kind of two-thirds
Okay, so just to kind of underlying that fact, because I think it's kind of interesting maybe not so long, it's not a QED, we've got a process of n vertices that goes, like, upper QD to the power n to the probability
We get more and more accurate tests, we include radiative corrections, so loops, a high value times alpha. And this particular series is the thing that's been tested really well when people say that QUD is the best
That's this one very
Well, I'm mainly talking about is when we have an attached laser pulse. These functions that have been functions of the intensity parameter and as they just made more intense
This shifts the importance of this parameters specifically, the leading process that's going to be dominant
What we're saying now with this objection is the high value regime, you don't know what, but we can't expand like this for many corrections. We have to include all orders of this. So we want to be able to write down. So I think it's quite compelling that
There's a region of Qd. Where we get absolute calculations. So we really need impact
Library is a final topic called radiation reaction
So radiation reaction is a very old topic going all the way back to like Lawrence and Abraham and
But it's a general question of what do you do and feel so intense that the radiation affects the trajectory of your charges.
So I'm going to provide plasticity first, and then
So, if asked you to calculate the radiation piece by electron and it collides for laser.
How do you do that? Well, an undergraduate at some point you can solve the Lorenz equation. This is the Lorentz equation by Brandon with a potential
But we use that to get trajectory, and then using trajectory currents which we use the wave motion to get to the radiation.
But I need to see a problem that to solve the first line for the trajectory, we need to know the radiation, the flow of the radiation trajectory
So pretty much this couple set of higher order groups. What we learned in undergraduate physics.
The potential is the laser, or the propagation fuel, just classically as well.
The laser interaction isn't E, so this faculty is being absorbed in case you think I have to go on the factor of E there
Then you purchase the token, you say, oh, the light's really intense, the radiation is going weak, so
we put the laser into the explosion, we've solved for the trajectory of the electron and laser, and then we use that trajectory in the equation to calculate what radiation the electron uses.
So it just rolls over. Okay, good.
I was so confused with my computer, and that's what the upside here, but I'm sure. Okay, thanks for the explanation. So
Yeah, so much do that fine, but imagine now that the radiation reduced is intense, or there's not there, or this information happens for a very long time. Then usually at the high order, so you can take that radiated field, and then you can plug it back into the equation of motion for the Lorentz equation, and you just solve for the new trajectory, take into account the fact that the radi
Has effects on the trajectory of the electron. So that's new trajectory, and then you put that into your weight equation, you get a benefit correction for the radiation, and you continue doing this until you have a ton of equations. And if this effect was very strong, you have to include all of these
Now, I'll go through that. If you do not leave summation procedure, you end up with something called the blind state of Han Derek equation
We're either to talk about approximation plan that we use describe what happens with electrons
Starting with my malicious question.
So here we have the Lorentz equation gain over and this is the part that's classical radiation reaction. So we see it's nonlinear in the laser field, and it's nonlinear of the electron, and it's got our radiation reaction parameter
Okay, so we solve this in place form, not always, but we can solve it in a framework background, and that's great because you want to look at lasers.
And one of the predictions of that is the following. If you calculate the
So, the measure of the electron after it scatters with laser in the same way
a fraction of the incoming of anxi. If it's a plane wave, that ratio is exactly 1. That's the Wilson-Woodloop theorem. Plane waves come up, accelerate electrons
But I think with radiation, that's not the case. And because radiation parameter here, which depends in a nonlinear way on the density of Bernard plates
Okay, so that's the classical case, but we're obviously interested in QD
Quantum radiation reactions is a general question about what happens. It's not… obviously, we don't think photons, that's photons create pairs, maybe there are loops. There's a much broader question in general
However, you can make a connection between QD and classical prediction by meaning in the gradient theory
And what diagrams are important? Well, of course, contour staffing, you know, all that goes in emits a photon, you know, recalling the electron, that's clearly an effect of radiation reaction. But also, in order to recover the cluster prediction, you need to at least
So it's kind of interesting that it looks reassess with quantum stuff, but actually that's the limit we've got this. So Luke's really important in our
So, we understand how to calculate, at least for leading orbit and QED, but the general problem is unsolved
Very successful, that showed a method of radiation reaction and a recent paper showing that there can differentiate the QD
radiation reaction form factor radiation reactions. But I think that we can do better. And one example of where we might be able to do better is in the following setup. So accelerate and dance
So again, as I've been trying to extol the virtues of Linux and properties of electron beams in this talk, this is about an energy standard around 1%.
And it's also a
And there's very much
Which highlights around 10, even a nonlinear regime
The strong field route is small, but the radiation reaction parameter is over a few percent. and the plane here is that by using the precision that you get from a mining methods from particles and accelerated physics, always nice physics, we can find signals of radiation actually not in the
But totally you're getting spectrum
I'll give some examples
simulations that we perform. So
This is an example of what happens to the electron beam energies after the collision. So there's no radiation reaction to the purple dashed line here, nothing happens.
Before the radiation reaction were classical, then what happened to this electron beam energies that they all get shifted there, in this case by about 10. All the electrons interact with the laser classically and they all radiate continuously
Contrast that with prediction
Not seen, but the expectation value of this GUI turns about the same, but the variance of the training is very spread out, it's
And that's because one of the features of radiation emission in QD is it's stochastic. So you could have an electron pass through the laser without emitting once. It's another one known as quenching
Or it lines the electron theorem might get to higher regions of the intensity of the laser beam, because it only makes stochastically than it does classically
So we have quantum effects which contribute to potentially the
Spreading the electron emission
When is that starting to occur? So this… this is kind of transverse momentum distribution along the electric field direction for laser
And you see that in the
No radiation case that's most readily learned in the quantum case there is
two dimensions like this. So this, you can see obviously the altitude goes down in the concentration center will spread in the transverse distribution. So the idea would be to be able to measure something in the tails
To differentiate quantum from classical radiation reaction unambiguously. You can also rotate the polarization plan for later
It should be around depending on what polisation plan is about
Sorry. So the collaboration form at the moment, obviously in difficult times between
So hopefully we'll have more to report in the future. I thought it was a nice demonstration of collaboration between
Okay, so
That's my summary.
I recommend seeing that you can do some really nice things with fundamental physics on high-power lasers. I only talked about QED because I think there's a lot of interesting things happening there. We can do things with lasers and natural reprocesses and DSM, but I decided to focus on QB for this talk.
The interaction between the charging fields is a non-preservative prediction of quantum field theory, which we could test in experiment. We don't have many of those typically non-preservative predictions that we have require
large providers are not difficult to get at, but in the interaction between lasers and electrons, this should be easy to access
I think it's a growing synergy between native effects, which is the engineering experimental prospects, and definitely developments in simulation theory
And this is including regime to my uni clearly becomes uncoupled with no methods to calculate this at the moment. So we definitely need impactful experiments. And I think that using precision, crucial precision
Rather than going to High Laser house for your attention.
Thank you