Jorge Pullin: So today we're going to have a panel and look Congress biology for stock will be by here mobile give us an overview that nearly will then connect help you see with full El que je and you and we'll talk about observations so you're more Please go ahead.
Guillermo Mena: And you see the screen there we do.
Guillermo Mena: nope no OK one moment.
Okay.
Guillermo Mena: Okay.
Guillermo Mena: So.
Guillermo Mena: yeah.
Guillermo Mena: So I was thinking for the invitation to be part of the panel.
Guillermo Mena: So the question is a little bit familiar to us is, why are we interesting is turning to handle the slowly.
Guillermo Mena: Essentially, I will say there is a good spirit or look quantum gravity and the other thing is that we want to extract the reactions that they eventually it could be a confronted with observations in order to make a theory falsifiable.
Guillermo Mena: Or the system, so the banning interracial activity also follows up to move to put into test the capability of the quantum effects to solve this mutual.
Guillermo Mena: Severe singularities of how this is done and the other things that are in the very ugly universe, we know the.
Guillermo Mena: should be large directors and they interactions they're going to addition interactions for responding to provide a sector would be important in those books.
Guillermo Mena: While they essentially a month, so the preparations that were affected by them afterwards have evolved during a classical inflationary and post inflationary a PayPal.
Guillermo Mena: Until a reaching what nowadays would correspond to large angular scales, and in this sense, we can we can say that being in cosmology a ultraviolet and infrared meets.
Guillermo Mena: So all these are important.
Guillermo Mena: We say features, or the framework, the other important thing is that the cosmological or situations.
Guillermo Mena: point towards.
Guillermo Mena: anomalies tensions between the measurements and the predictions.
Guillermo Mena: and indicate the least our university statistically are normally a i'm hoping the possibility that in fact there is new physics and this gives us the opportunity to look for possible and.
Guillermo Mena: In doing this now important feature is that we have to make compatible this alien variance is more or less than 60 salvation of the cosmic microwave background, with the introduction of the quantum scale.
Guillermo Mena: OK so.
Guillermo Mena: The nice thing is what is that we understand my look want to perform so essentially we understand the application of the methods of look quantum gravity to first melodic is sustained.
Guillermo Mena: And since the relation between the two things are not a fully a solid establish a did may assist me with this, but on the other hand, through that from different restrictions.
Guillermo Mena: from different proposals we have arrived to situations that are qualitatively similar like reason they are playing soccer bounce.
Guillermo Mena: All the effective classical behavioral the universe of them Okay, and this sense, there are a few sounds there seem to be quite robust okay in at least in order to study, what kind of effects we can expect.
Guillermo Mena: Now, as I was saying before molly must proceed with the what we call this an hour abroad to cosmology in the sense that.
Guillermo Mena: We say that there was a slow roll inflationary face and that the vacuum stay there was once a week and the success of the system, our approach is so impressive that.
Guillermo Mena: In fact, it is a kind of paradox in the sense that some people who say that there is no room for funder effects that can be are several.
Guillermo Mena: while others will say that if we released under X, Y you opening pandora's box and then we can have all kind of phenomena.
Guillermo Mena: And, in particular, radical changes in our faces okay and look into cosmology and certain says must keep an equilibrium between the two things.
Guillermo Mena: You must at the other day just lead us to some modifications, but not very practical Okay, so in practice we we described the departures from homogenized and so to be as perturbations.
Guillermo Mena: What we do is to consider backgrounds of nature that behave in an effective manner and such that they on, then the reaction of the preparations, you say then negligible of various.
Guillermo Mena: And these backgrounds are typically present evolves and the main.
Guillermo Mena: person that we make is whether these subjects stay the primary operations of how they they will.
Guillermo Mena: OK, for that there are least two routes you look on the boat molly to achieve have to arrive to a point of view theory in especially impulsively often to measure.
Guillermo Mena: That are the hybrid approach or maybe there is maybe Okay, a this simulator similarities between doing our homework okay.
Guillermo Mena: Let me say that they have read approach is principal your starts with pompous partial sections rotates the action up to whether epic terms in the activations.
Guillermo Mena: This leads to a full swing global system that contains both the background and the preparations and usually, when one takes a continuous long compared to.
Guillermo Mena: The rest medical approach, on the other hand, one is started by by assuming that the battery actually was negligible, something that can be checked out was for.
Guillermo Mena: Consistency and that moment the coastline of X essentially the background usually they the quantity stays out of planes at an adult and effective.
Guillermo Mena: scripture in which the main quantum corrections can be encapsulated in rest metric and the dynamics of the activation our equation so motion in which they the effect of these two buckets one is a kind of meaningful approximation, in the sense that is given by inspiration.
Guillermo Mena: In most cases, a in practice what we consider our backgrounds that admitting effective region you look on the Bologna the perturbations of described by fox conversation.
Guillermo Mena: And the most of these perturbations are a big satisfy equations that can be rating as the dose of our monocle see later, but we've amassed that depends on the.
Guillermo Mena: story.
Guillermo Mena: Okay.
Guillermo Mena: So what are the difference if any.
Guillermo Mena: Well, in principle, is through that heavily look into goes molly can leave room for what reaction in the sense that definition of the.
Guillermo Mena: variables that form economical sense for for the in some of the background of the populations include corrections to the variables for the background are quadratic.
Guillermo Mena: Okay, the others a feature is that the system has a particular string and the sense that maybe some but reaction was the preparations on the background.
Guillermo Mena: But the practices you one concealer walk around with a negligible but reaction this difference essentially disappear Okay, so they only difference that remains is the way in which the background dependent mass is calculated.
Guillermo Mena: In principle, in hybrid low quantico smalley one is does with economical description, in which the river is given by commentators will have insomnia, and only after computation everything is evaluated on reactors.
Guillermo Mena: In the various metric in principle as so region formulated one has affected trajectories and even the derivative is her calculate is on these directories.
Guillermo Mena: What means that they are given by commentators question market with effective coming tanya.
Guillermo Mena: And then, this is not a subway the same when the quantum effects are very important, that is precisely the region in which we believe that they could be effects of groupon to cause molly and which are the ones that we want it is the only.
Guillermo Mena: So, for instance, here, this is a graph in which we see around the around the mass for the hybrid a approvals for the various medical.
Guillermo Mena: But for the rest of the evolution the masses are complete this.
Guillermo Mena: So the other thing also a concern in the background is that, after is real so when they advance which is a they say various money in terms of.
Guillermo Mena: Things in terms of a few a a fraction so one thing being afterwards they say every year of classical evolution, there is no.
Guillermo Mena: it's not exactly as in the standard approach is not a slow roll inflation, we have first every year in which they energy on the data is dominated by the kinetic thorough.
Guillermo Mena: And after was the beginning of inflation typically has the first roll video essentially because they kind of solutions that.
Guillermo Mena: We are interested in this show certainly inflation okay very important questions whether the modifications to the predictions of a standard approach will come.
Guillermo Mena: Either from these classical region is non standard have thrown the quantum theory around the bombs and these important because may happen that the classical notifications, are they say larger than the quantum ones, and therefore we cannot observe me.
Guillermo Mena: A in this introspect, let me say that with reasonable choices of working, what happens is that won't fill the specter of his vision of power of the scale, in which this appears is different for.
Guillermo Mena: A non standard Jeanette will release the case scenario for groupon to put in one case this game is the beginning of inflation and the other is the.
Guillermo Mena: Other way around the world okay and typically the quantum scale for groupon to carvallo is larger than the other, and this gives us hope that if any of these superficial appeared in the power spectrum, we have more chances to detect the one quarter only to look into.
Guillermo Mena: OK, so the other point that we see is that the predictions, we believe strongly on the choice of vacuum in state they have we essentially three proposals in this.
Guillermo Mena: direction one is the use of the article states that is a way in sentences of the analyzer networks which are working for me because, being other situations.
Guillermo Mena: A person there is to what extent is a natural thing clearly quantum regimes, and they are things that they typically lead to oscillations that when our age.
Guillermo Mena: Can in haste, the power in the spectrum because of that, it has also been proposed to find a stage that minimize the circulation is called an oscillating vacuum.
Guillermo Mena: In this case, the progress in which regions we want who a let's say a minimize the installation just in the quantum a bridging also in the non standard classical period or in the combination of both of them.
Guillermo Mena: Are the things that typically this a minimization of their solution is done numerically and we would like to have a night characterization of these kind of popular is because, when done peacefully connection with the young, as in particular violate that have only session.
Guillermo Mena: Now the third proposal is what typically our usually we put they asked like a good presentation proposal essentially is to sing a family office space around the wound and.
Guillermo Mena: From then in the Center it minimizes the contrast, these are they are compatible with homogeneity and so to be and to sing one of them by semi classical requirements at the end of inflation.
Guillermo Mena: Of for a approaches that are not the best metric a there are certain is in the definition that should be somehow let's say a clean out or improve, and we are things not clear how to extend their their proposal to GR because there is no bounds okay so then we just sorry.
Guillermo Mena: Let me just finish I essentially vesely this task to kind of feeling of order but we that the prediction will be so sensitive.
Guillermo Mena: So back in that we cannot say anything to at least let me send the following message which I think is important.
Guillermo Mena: We should look for a vacuum and state that the first thing is that the changes with respect to once babies have a small just for setting It ranges of wavelength of mostly say.
Guillermo Mena: The other things I should be based on first principle is not that we forced the vacuum, just to obtain the power spectrum that we have set, this will not be satisfactory.
Guillermo Mena: They are theory, they should be appealing optimally other dynamics in particular around the bounce it should be sensitive to the escape that intrinsic or.
Guillermo Mena: So, thank you very much, these will, I want to say.
Jorge Pullin: Thank you very much, can you please stop sharing.
Jorge Pullin: Please go ahead.
Jorge Pullin: Good.
Daniele Oriti: will discuss how cosmological economics can be seen from the point we have quantum gravity framework, so this sort of embedding.
Daniele Oriti: conceptual and technical into the full framework of forces as the potential water company mutations of cosmology.
Daniele Oriti: to test the results that.
Daniele Oriti: they've been doing so far in that context and out say important to to raise your questions, because you see things from a different perspective so most of my discussion with the goal of simply.
Daniele Oriti: elements for later discussion will stop to think about it is closely based on development say security formulation of.
Daniele Oriti: gravity and so there will be, of course, is very many connections to the quantum gravity from families.
Daniele Oriti: But despite it being most inspired by results in a particular direction that I would claim that the results cern's most of the insights and the other more general validity, so the first point is that if we think about cosmological dynamics.
Daniele Oriti: To to focus on cosmological elements from the point of view of the curious to me basically restricting attention to a few global observable.
Daniele Oriti: In fact, this is to also from the point of view of generativity.
Daniele Oriti: This means from the full quantum gravity point of view, to focus on some collective variables so collective observable and collective states, this means that cosmology sugar should arise from some form of course brain.
Daniele Oriti: Now, because grading in general is expected to be very difficult.
Daniele Oriti: And symmetry reduction, which is what gives rise to cosmology can be seen in fact that's a very drastic type of constraining agree to simply remove an infinite number of degrees of freedom not directly correspond to the global observable you're interested in.
Daniele Oriti: Now this reduction in general, if you perform it at the quantum level is a singular from the point here.
Daniele Oriti: These are called doesn't mean that there's anything necessarily wrong with that, but I should expect the ICO screening that is less drastic to produce modifications to the results i'm creating more articles.
Daniele Oriti: In fact, what happens at least in the refrigerator framework is that we, after some.
Daniele Oriti: Drastic but not that drastic action within the future if we do obtain a cosmological where we function on being super space as the dynamical variable but it's actually a thing this is sort of always parameter labeling collective states it's not a quantum state itself.
Daniele Oriti: It does correspond to something like another dynamic density, whose domain is being used to perspective.
Daniele Oriti: So in this simple as approximation just that there is a field operator and it says potential value in a given troy's of ground State there is will give some the cosmological we function of mutual respect and then this way function, just like in.
Daniele Oriti: Three like in terms of some density, for your fluid that some face.
Daniele Oriti: Now this is technical consequences, I just want to point out one conceptual concepts means that the.
Daniele Oriti: This is the case, he is is how a cosmological way we function liking quantum cosmology consultant from the hood cheery there is no corresponding he'll be space for the status of such we functions, so there is of course the underlying code base base of quantum gravity states but.
Daniele Oriti: there's no restricted Hebrew spaces such as we functions within the food to.
Daniele Oriti: The other consequences that the observable to automatically be with continuing gravitational physics, as ever, just not as eigenvalues so the quantity as to play the role of the scale for the for the universe in in such either Ivanovic like personal journey some appropriate average.
Daniele Oriti: weighted by the density of the fluid the l some variable.
Daniele Oriti: Okay at this level, in an important role will be played necessarily by some quantity play somehow enabling or counting the number of degrees of freedom.
Daniele Oriti: In this specific context that, like I mentioned grew from theory, this is given by the.
Daniele Oriti: integral models for the way function so is, in fact, that the literally the average number of the right or the microscopic building blocks, and this is in fact an observable in the quantum theory that has no counterpart that.
Daniele Oriti: If you just look at quantum cosmology itself as an observer, where that enters the dynamics and evaluation of interesting quantities and particularly is crucial to do fluctuations small and to define a semi classical really large volumes.
Daniele Oriti: The second main point, the following from the five minute, you see, the smaller the essence of the American effective coarse grained the dynamics.
Daniele Oriti: And literally in the EU feature comparison some sort of idle dynamics, we find a pencil such a cosmological we functional neutral space is that the dynamics for such effective way function is genetically nonlinear.
Daniele Oriti: This is what you should expect in general, whenever you do some cross training or go to some either dynamic approximation, but of course it means that even assuming that the linear part the bh like loop on to cosmology equation.
Daniele Oriti: There would be no linear addition to that which may have any general has cosmological consultancies.
Daniele Oriti: and number of other points, is that the gravitational coupling said that you see it is effective lever once you match it GR are in fact functions of the underlying.
Daniele Oriti: parameters in coupling so the quantum gravity formulas that may not be directly.
Daniele Oriti: interpret this gravitational because there's No one to one correspondence between parameters in the effective dynamics and parameters in the fundamental one and meaning that I don't know something like effective gravitational constant would be a function of several.
Daniele Oriti: The parameters of the microscopic here.
Daniele Oriti: The linear restriction would look at these formulas much more like a standard open to cosmology setting still without an associated to the space.
Daniele Oriti: The reason why there's no hyperspace and maybe I should have said, literally simply that.
Daniele Oriti: Generic question for your way function well, I know superposition software solutions to not be the solutions.
Daniele Oriti: Okay, by the way, is nonlinear contributions, at least in a very simple cases if we were able to study them and.
Daniele Oriti: Their contribution to the cosmological dynamics that seem to be actually bought the genetically the the the seems to some cosmic acceleration and normally I never made at times and so some form of effective that kind of.
Daniele Oriti: Okay, an interesting question, at least for me is that if you see cosmology this second as some sort of condensate that open army said they would be expectations out of the condensate and it's unclear to me, first of all, these have to be.
Daniele Oriti: treated so to give some modification of the cosmological genomics for a given company to the universe described by the arguments for the way function or somehow that can be mapped to some new form of content for the universe and effective new motor component what is.
Daniele Oriti: The next point, which is a general.
Daniele Oriti: For quantum gravity Again I say, and we have to really rely on this is hugely in starting cosmology from theory is that.
Daniele Oriti: evolution can only be relational, and so we need to select some degree of freedom to play the role of clock, but we also have some conditions.
Daniele Oriti: Also, that such clock is in fact that a good clock and these are conditions from the relevant quantum states that they will allow instructional cosmological dynamics.
Daniele Oriti: It should work with the eigenvalues of the clock this corresponds to the point of your the jury to inflict the big states, and this is, it would be highly fluctuating conjugate.
Daniele Oriti: degrees of freedom to the clock runs and now the questions that I am be very interesting interested in hearing your.
Daniele Oriti: opinion and learning more about that that is what are the conditions for choosing o'clock.
Daniele Oriti: Within the food Curie and, in general, cosmology and and the fact that they could be especially in these calls green setting and mismatch.
Daniele Oriti: Between the fundamental club degrees of freedom and the effective once I give you an example.
Daniele Oriti: suppose that I counseled to full quantum quantum gravity or goofy curious so at the level of the fundamental degrees of freedom which are discrete tech citations I know.
Daniele Oriti: pathological geometries in general I couple what looks like a well defined must less free scared of you like some form of this presentation.
Daniele Oriti: Then I do some custom training at the effective level there's no obviously reason respected this sector, because the freedom will behave exactly like a muscle is scared of you.
Daniele Oriti: It may be some.
Daniele Oriti: Potential generated by the equals granting some of the features of the.
Daniele Oriti: dynamics, more general, and this is important because, of course, I would like to choose his master's get a field as a clock from the point of view, the fundament theory.
Daniele Oriti: And then I may want to treat it as a clock at the effective cosmological level at this quarter screen there either ergonomic level.
Daniele Oriti: But if you factor in effect the potential is generated by the current sprint procedure and it treated as a Muslim says get a few people that was my interpretation I problems matching with the results of dynamics written international language to such clock.
Daniele Oriti: So this is, you should do to be taken into account and then questions that to do again with the how much physics actually depends on the choice o'clock or whether we should expect environments.
Daniele Oriti: physics and machine to physical clock so realistic clocks with their own interaction back reaction, the geometry, and so on, and what is it from relational general covariance as transformations between the physical frames no coding frames.
Daniele Oriti: Okay, everything I said about the clock, in fact, actually be generalized the two routes and that the important point to me is that, from the funding from the point of view, the fundamental theory if I want we struck a cosmological dynamics between the two nations.
Daniele Oriti: I also had to express that cosmological perturbation cheering relational terms of respect to such internal charges of internal degrees of freedom playing the role of routes and the number of issues arise here i'll go.
Daniele Oriti: will not discuss each of them, so that there may be more time later for discussing.
Daniele Oriti: And let me just say that up the ori if I only look at the arguments would be effective, we function as a standard mini super space in which I see the skatepark.
Daniele Oriti: Some additional matter component, that the math degree of freedom my users o'clock and then master degrees of freedom my users rob's.
Daniele Oriti: I can start you're ready to be sure to read this level, even though i'm working just with the world looks like initial space, because I can express relational observable with respect to.
Daniele Oriti: The subset two degrees of freedom given by values of their own fields.
Daniele Oriti: So, clearly, this can only be an approximation to the full story, because the full story requires full super space, not just that it functional municipal space that it is to admit after them clear to me in which approximation actually respect that this limited description, with some validity.
Daniele Oriti: Last, I just want to mention that, if cosmology comes out of this effective level as either dynamics so first of all it takes place in one particular phase continuing phase of the underlying system.
Daniele Oriti: So important role will be played by the running of the various couplings and we need to check what happens at criticality so like for critical various have such carbons because it will affect because one of the most effective equals more experiments.
Daniele Oriti: In particular, when general consequence is that that the bouncer that seems to be reproduced in the world that has been done so far, just like you know, to see if he's the from the point of view, the effective dynamical equations.
Daniele Oriti: It is reproduced in what is actually a very dangerous zone, not for the other Apps image because small values.
Daniele Oriti: correspond to smoke that uses the number operator in the volume is an extensive quantified in terms to the number of degrees of freedom.
Daniele Oriti: And so the bounces in the redeeming Richard not really certain about the validity of the other for the approximate overall just accepting very few degrees of freedom.
Daniele Oriti: And so it could be that, depending on the order, depending on the dynamics the bouncing fact that can be trusted their own in some for a subclass states it but genetically need to resolve to describe the corresponding physics, to the more fundamental economics, which doesn't have.
Daniele Oriti: affected the space time description.
Daniele Oriti: Okay embedding everything the food, you should allow that he, I asked for help, because I don't know how to do it.
Daniele Oriti: should be allowed to ask questions about yarrow time and the initial state of the universe, because it should allow or to ask questions I will give them from the entropy and here interesting issues.
Daniele Oriti: to differentiate the entropy the food.
Daniele Oriti: system and the entropy of the universe, from the point of view of the physical frame, we are chosen to describe evolution and localization because that requires singling out that not considering and subset degrees of freedom.
Daniele Oriti: you're going to answer these type of questions to have a better foundation for statistical mechanics quantum gravity in absence of any preferred time that action in this is a general issue.
Daniele Oriti: Last the I mentioned that I know running of goblins and criticality and face traditions, well, it.
Daniele Oriti: should be able to us whether the face rendition of the underlying system.
Daniele Oriti: As a cosmological individual itself being close to criticality affects the spectrum of cosmological perturbations, for example, if criticality is related to the early universe Okay, and there are many more things that, of course, they don't mention, and I thank you, Mr.
Jorge Pullin: Thank you, please, share your screen.
yep.
Jorge Pullin: So Yvonne.
Jorge Pullin: you're muted, I think.
Ivan Agullo: Can you hear me now yes.
Ivan Agullo: And so.
Ivan Agullo: In the last part of this of this panel, I want to give you a global and simplified and of course bias by my personnel, be a.
Ivan Agullo: comments on the connection between ltc and and observations and and so, first I want to make contact with many things that the urinal have said and also partially daniella, of course, all this is the summary of contributions by many people.
Ivan Agullo: And I list them all here, probably forget some people I apologize, but rather than then mentioned them one by one, just for the sake of of time.
Ivan Agullo: And so, and and the main ingredients of of help you see as as both be your mind and daniella has mentioned is similar to production.
Ivan Agullo: which we know is a drastic simplification and important physics can be missed the motivation is historical motivation, you know scimitar of action has been.
Ivan Agullo: essential tool to make progress in physics in gravity cosmic physics, etc, etc, so we want to follow the same the same approach, without forgetting about how drastic the simplification is.
Ivan Agullo: That nearly also mentioned that, from the viewpoint of the full theory, it is not there is no canonical homogeneous and I satrapi sector and in gfp that he studies very clear, that is not even a better space.
Ivan Agullo: For the genius and for the cosmological sector a Annie oakley G dynamically, the problem is even worse because we don't even have hamiltonian on which we agree on.
Ivan Agullo: So it is difficult to argue whether ltc is compatible with the dynamics of our full theory which we don't really agree on, so this is rather a to a breach each you know both benefit each other.
Ivan Agullo: So, but in spite of these limitations, in my view is that this this field has been built using what I call a physicist viewpoint, in which you know.
Ivan Agullo: model or quantum theory of the cosmos has been built a you know, using what we know from the full ferry trying to encourage as much as we can to the full theory.
Ivan Agullo: and making simplifications and when we don't have the tools to anchor to the full theory just make responsible choices using physical intuition and general experience from other from other fields, and we do that, you know, with the goal of building a self consistent model.
Ivan Agullo: Out of which we can connect with observations and i'm also with other frameworks for the every universe, such as inflation or a standard model, etc.
Ivan Agullo: And you know, the main goal is to aim at that data driven approach you know, try to make contact with observation, in spite of the simplifications that we leave on the way.
Ivan Agullo: And, and this should provide, and this is the last sentence of this of this slide the foundations for further scrutiny and improvement and and many examples have been shown in daniella in Danielle West contribution.
Ivan Agullo: So this is the goal so several things have been.
Ivan Agullo: achieved so far, the main one that we all know, is singularity every solution, and this has been done, following the general approach of focusing the general.
Ivan Agullo: A program of starting first with the simplest model and then adding difficulties, one by one, like a special code mature and so to be.
Ivan Agullo: Even infinitely many degrees of freedom in go the models, etc, and so far indications seem that this resolution is robust and I think you know they.
Ivan Agullo: The analysis provides a very interesting understanding or example of how you know the peculiarities of of look quantum gravity kind of help ass to get rid of similarities of the classical theory, so there are very interesting messages that.
Ivan Agullo: I faced have many choices are in the way which means to be a father justified or anchor to a more fundamental viewpoint but but but and we don't need to forget about them.
Ivan Agullo: And so far, you know the relations of milk, you see, with a full full El que je and N, and you know, there are several in the market very interesting.
Ivan Agullo: avenues, and it seems that this singularity of a solution so far as a common denominator of of most of them, and even the pause bounce feigns face seems to be a robust.
Ivan Agullo: Interestingly, some differences appear in the p bounce face and they even lead to different observational predictions so So these are an example of this to a bridge between ltc an energy, which I find very, very interesting.
Ivan Agullo: Okay, so so after this brief a connection with the full theory, let me go to the main topic phenomenology I think you know the motivation is not really needed here.
Ivan Agullo: We all are physicists and we know how important is to make contact with observations, and in particular for cosmology right because in cosmology a you know.
Ivan Agullo: The blank area of the cosmos is within our past life COM is not hidden behind an event horizon, so you know we don't need Planck scale physics to leak out of a horizon to be observable.
Ivan Agullo: Rather, what we need is that blanket scale physics pseudo base all the complications of the history of the cosmos you know blank skill physics, is not washed away.
Ivan Agullo: By the complex physics, of the cosmos between today and the banker and and we are aware of that many of the of the blank escape features are going to be washed away, so there is some limited what we can get now from the early universe, and the question is, what exactly those limits are.
Ivan Agullo: So what we have learned so far.
Ivan Agullo: And is you know i'm going to summarize a few messages for the sake of time.
Ivan Agullo: The first one is failure of theoretical is something that I find very interesting is that ltc starts from our natural geometry that one done geometry described by away function.
Ivan Agullo: A, out of which there is no clear notion of counsel structure, however, once you put one on feels propagating on that fundamental geometry.
Ivan Agullo: and imagine a pseudo Romanian effective geometry appears, out of which one can talk about cost structure, and I think this is something that.
Ivan Agullo: You know, we expect in general, from quantum gravity that the cost structure images once you have fields proving the quantum geometry, and you know, a very nice example we may view be in you know you'll see.
Ivan Agullo: Next that's ltc provide a mechanism to generate the primordial so perturbations that we seem to see me and almost a scaling bottom a spectrum, and that was the initial hump and so far, the answer is no.
Ivan Agullo: No.
Ivan Agullo: The problem navy's that help you see maybe it's too simple, we only have the blank escape you know to see.
Ivan Agullo: And it's difficult to see how the inflationary scale, you know energies game, for instance, is going to emerge out of accuracy so so look you see it's not enough so far.
Ivan Agullo: Maybe dressing ltc or going beyond that you see will provide additional structure, out of which we can build a.
Ivan Agullo: mechanism and and daniella provide a very nice and intriguing example from from God, he told us that you know.
Ivan Agullo: The nonlinear couplings between you know this fundamental.
Ivan Agullo: structure, you know provide newest structures, out of which one could build an effective cosmological content so and there is an example of how dressing accuracy with something more complex may may solve.
Ivan Agullo: may be young the limitations of hypocrisy, but so far you look, you see, that is not the case, so if you see has been used to complement other mechanism.
Ivan Agullo: To extend well known mechanism in the market to the blank escape and with the with the goal of completing completing them from the quantum gravitational viewpoint and hopefully to add some extra features, to the baby chance that we can test with observations.
Ivan Agullo: That is the goal of this program so far, and you know in this to cartoons I illustrate that you know, the main idea why the balance of focusing can affect the cmt here in red, you may have seen this this before I have shown them many times, this is one more.
Ivan Agullo: In red is the the the radius of curvature of these emerging geometry that better patients feel, and this is the case of the you know, on the left.
Ivan Agullo: You have the the GR with a big bang on the right, what happens with a bounce the red line and and then in blue are the wavelength, of a few perturbations.
Ivan Agullo: as a function of time and we see that in the right hand side in the right blood that the wavelengths are long enough, they become comparable.
Ivan Agullo: To the quarterback for Sky, the bounce and because of that they will defeat the evolution of the special operations is modified by the presence of the bounds.
Ivan Agullo: shorter shorter wavelength don't care about the balance for the same reason that we don't care about the curvature of the earth, he is different, but longer wavelength care about the balance and that notification will be imprinted in the CME.
Ivan Agullo: Remember the cms our history book, and these are the the accidents that are registered in the car so so so so so therefore from from from from a bounce we expect some quantum route you some corrections at long wavelength large chunk rather scales in the sky.
Ivan Agullo: Okay, but when trying to make concrete predictions are there free parameters that we need to choose, and the answer is, of course, there are three parameters, yes, a few of them are a how much expansion, there is between the balance and let's say today.
Ivan Agullo: That is something the theory doesn't fix and it's a free Parliament.
Ivan Agullo: What is the initial state for perturbations that was discussed by nicely by a baby or more in detail, etc.
Ivan Agullo: And to me, this is not surprising, you know all there is we, like a love are free of us are full of free parameters.
Ivan Agullo: In Dr Dr there is no a solution for the universe, that is a family of solutions and we choose when using using data right a standard model inflation, etc, so this is this is great expected from my people.
Ivan Agullo: The important question are the choices of these parameters for use in agreement with data and the answer is yes, there is in fact a huge window for which we can you know, complete the standard model completely inflationary paradigm, and still have agreement with observations.
Ivan Agullo: Can we Father single out a concrete choice of initial data and the program so far has been you know, has followed this ambitious strategy.
Ivan Agullo: The strategy, the ambitious strategy is you know, is to use these anomalies that the year more has mentioned, which are features that we seen the cmt and cannot be explained by by the standard model.
Ivan Agullo: One by one, they are not very significant statistically just below or around 30 cygnus but collectively as we are must bring to us, they may tell us that there is new physics at lunch and worst case, in the end.
Ivan Agullo: So the program is whether ltc a weather in ltc that is a choice of the parameters, the free parameters that make.
Ivan Agullo: That make excuses to account for the song.
Ivan Agullo: Again, this is what I mentioned before, as you know, as a data driven approach use what we see in the sky to fix our our our freedoms.
Ivan Agullo: And they also using different methods and there are many avenues that people have follow and do that.
Ivan Agullo: i'm going to explain you one of them, just for the sake of time, and also because I am by yes i'm going to explain you the one I have contributed more recently, which has to do with nano China.
Ivan Agullo: So remember nano shiny, these are the effects of the next to lead in order there in perturbation theory the lead in order is free penetration theory next to lead in order you have a self interactions between perturbations and they produce what we call non oceanic.
Ivan Agullo: One of the effects is that the three point correlation function, you know the three point functioning there in real space is different from zero and zero if you neglect self interactions between perturbations.
Ivan Agullo: And he I know our group, we have computed this number of shiny piece in full detail I am doesn't even you 30 seconds summary.
Ivan Agullo: And the main message is is that there is a choice of parameters of the theory for the week this notion correlations are sad that within our humble back this is what I what I.
Ivan Agullo: mean by this conference that I would have a badge within our hubble patch they don't know Shannon these are small and below observational upper bounds.
Ivan Agullo: And however they are large enough to buy gas or to affect it's likely the coupon correlation.
Ivan Agullo: And this affects a they can produce in a very subtle and concrete manner that by i'm not explaining here a several of the anomalies that we see in the in the sky.
Ivan Agullo: such as this forward suppression, but the information also these bipolar anomaly, which looks completely different from poverty pressure they bought anomalies as a sort of be in one direction in the sky and that can can image in a concrete manner by by this notion motivations, etc, etc.
Ivan Agullo: Even more than that you know these results have been have attracted the attention of some well known cosmologist that has nothing to do with with milk, you see.
Ivan Agullo: A and, and these are these are very recent paper October last year and and what they say, is the following, you know just just to.
Ivan Agullo: To summarize what they do, let me use this analogy with Lego data in Lego data, we know that the signal is will be young will below the noise.
Ivan Agullo: And you may wonder how the hell, can we see the signal when the signal is well below the nose and the reason is because we have a template.
Ivan Agullo: If we know if you know what the shape of the signal should be you can accumulate enough signal to noise ratio, even if the signal is buried under denies.
Ivan Agullo: The same This is exactly what they say here, because you know because we provide our template the shape of they don't go Shannon.
Ivan Agullo: You know, out of a bounce of accuracy, a if you know the shape, you may accumulate enough signal to noise ratio and, in principle, you know this signal can be detected using blank data.
Ivan Agullo: And I am aware that they are doing that that analysis so so I find quite interesting that cosmology is happy nothing to do with accuracy.
Ivan Agullo: use our templates to look signals in data, you know in observational data.
Ivan Agullo: And just to finish, let me finish with with three comments and and be some similar strategies come together with further predictions.
Ivan Agullo: of things for most in particular optical depth, etc, and we are waiting for data, in particular for cancer modes and and once the data is here all these predictions will come out on the table again.
Ivan Agullo: Similarly to what happens with gravitational waves, many of the subtleties of mathematical GR now are.
Ivan Agullo: Are are interesting again because we have data so once we see things for themselves if we see them, then this will be part of the game and there are other places where quantum gravity could be useful.
Ivan Agullo: daniella has mentioned, you know whether quantum gravity can produce and imagine cosmological constant either for the area of like you say like time universe.
Ivan Agullo: Also, they have attention, whether you know quantum gravity Can I take that and I know that Alejandro barriers Edwin Edwin Edwin danielle's with our ski they have arguments with that etc.
Ivan Agullo: So just to finish.
Ivan Agullo: We all know that that that that elk you see it's very simple and it's made of drastic simplifications a bad it provides a complete model, out of which we can connect in a concrete manner and precise manner, one to gravity with observations and.
Abhay Vasant Ashtekar: And even do anything on the slide we only see final comments.
Ivan Agullo: yeah no I don't have anything just might want.
Ivan Agullo: Thank you anyway and and so so and and and so ltc provides a concrete path a concrete, you know.
Ivan Agullo: A way of connecting fundamental quantum gravity with observations and and, of course, many things we will be modified in the future and many new inputs will become will come from the from the full ferry.
Ivan Agullo: But it is my view that this path that bill QC has produced, even though it is based on assumptions and physical intuition, you know it is, it is real progress, which will allow us to dress it farther and modify what it needs to be modified and am I going to stop stop here, thank you.
Jorge Pullin: Thank you, we can now take questions.
Jorge Pullin: Western please.
Parampreet Singh: Can I ask some questions.
Jorge Pullin: Western raise their hands sorry.
So.
If I, if I may, pick up the from the last.
Talk by.
by Eva and I have, I was pleased to see that he mentioned the problem of generating primordial.
perturbations, I just wanted to mention that we have been portrayed in a research direction.
Sorry, to address this problem man.
Western: That is so it was reported in in Asia paper called the promoter fluctuations from quantum gravity and the idea is to use as a vacuum state the heart looking state resulting from.
This being formed dynamics so it's an approach based on on the full theory of the food from dynamics and what we have is the possibility to compute correlations.
From the full theory, and so the limitation of our first paper was that it was a very simple model we look for the for the loop conference to present the results, in particular, so these results are made possible by the advances in numerical methods, especially by students of ours.
Follow frisoni.
And the the the results we have so far that there could be there could be more entanglement stronger correlations than what is expected in the usual.
bunch of previous state, so I mean afternoon, my comment, the reason why I mentioned, this is also to make a call for collaborators, so if more students and postdocs want to join us in this The challenge now is to connect.
With an effective states that can be used for instance with the standard the loop cosmology techniques.
Ivan Agullo: Wonderful fantastic Thank you I didn't know what that and I am looking forward to see the details.
Jorge Pullin: Around.
Jorge Pullin: Oh.
Parampreet Singh: So my first question is to gamma gamma in your very last slide you showed a lot of the power spectrum probably one with the.
Parampreet Singh: oscillating state idiomatic states what's the glucose so I was wondering where does that glucose which has a lot of power suppression comes from is that from milk, you see some water.
Guillermo Mena: Yes, it can strong oscillating back here is a wisdom work that will be able to Italy.
Guillermo Mena: me publishing Jacob Okay, so it says, an application like a distilled other Assange an ethical approximations but the nice thing is that you see that there are two aspects of suppression.
Guillermo Mena: The first one is the quantum the corresponding to loop, but there is an additional suppression of these beginning of inflation, this is a nice thing Okay, because you can see both of them.
Parampreet Singh: But in this model, do we have a some I think I remember some of the recent papers, or do you have a fastball kind of a scenario or.
Guillermo Mena: yeah I mean essentially what we did in that paper were to compare and evolution in USA that typical background for loop or a.
Guillermo Mena: Look, when the cosmology it, that is our lives and, therefore, that the very beginning of inflation is not the slow roll okay.
Guillermo Mena: I compare that with the same kind of solution, but in general relativity which the difference is only that you don't have the bounce.
Guillermo Mena: And you continue backwards in time until you reach a big fan okay Okay, and to try to see what were the differences in the power spectrum the spectra that you have, in both cases, they said, the only thing I mean the good thing about things that we were able to.
Guillermo Mena: Implement analytical approximations is allowing us to compute a Secondly, the power specter, on the other hand, they are approximations Okay, so in the future the nice thing will be to try and prove that they are you mentioned relax okay.
Parampreet Singh: Thank you, so I have just go Comments like one Daniel in your talk you mentioned at one point that the bounces of gaining the hydrodynamic limit.
Parampreet Singh: When you're selling this card is yours and probably like a a got an impression that you want to say that bonds probably cannot be trusted, but I think like.
Parampreet Singh: We have a very similar situation and you see if one looks at the full quantum dynamics and one considers states which are.
Parampreet Singh: How you squeezed orange juice, which are widely spread states which have very small momentous in the skill of you there the effective description, it is true it breaks down.
Parampreet Singh: But if you do the full quantum analysis that the full states and you'll have to use SPC for that you still see about.
Parampreet Singh: So just because we do not recover do we reach the limit of the validity of the approximation I don't think it implies that you won't see probably about it may still be true in your approach, but at least in accuracy, we do not see.
Parampreet Singh: Running playing another so just a small comment.
And I.
Daniele Oriti: saw.
Daniele Oriti: The only logical implication, I wanted to put forward is that if.
Daniele Oriti: A quantum cosmology equation comes out as the hydrodynamic one and, in fact, it turns out to be no linear equation, for the way function.
Daniele Oriti: Then the volume basically goes with the particle number.
Daniele Oriti: The number of the data because it's an additive quantity, so the approximation which one recall vs is.
Daniele Oriti: No linear essential company cosmology as I go that makes it will then have to be trusted for very small values of the particle number.
Daniele Oriti: Now, the only logical implications that that one should have expected to be genetically tested, because it will depend, a lot of what precisely the current the fluctuations do in the full system.
Daniele Oriti: He said the only logical implications that that is a danger zone, this is exactly where the little mermaid approximation becomes a questionable.
Daniele Oriti: Then may will be there for large classes to say even for the stage that turned out to be the physical ones, because of that I don't make time boundary conditions it's all the bounces festival because, despite the particle not being smaller fluctuations are under control.
Parampreet Singh: So if I can add like in fact like exactly like what you're saying, as the when the particle number small which corresponds to small volume this word the kind of states.
Parampreet Singh: I was very worried about and we studied extensively with the fluctuations become very large and urgency, but you see it turns out that in fact the.
Parampreet Singh: One might thing that the fluctuations will destroy the rounds, but it turns on the fluctuations actually help.
Parampreet Singh: Having the bounce much earlier, like the spaced and curvature at crystal bonds occurs tons of women.
Parampreet Singh: In fact, like away and British than later, were able to write some sort of an effective description, with a modified energy density, which shows that the bounce density is lower, so I think this is something very interesting, which might be useful or virtual.
Daniele Oriti: You know, we also find that the listing the models in the setting we restarted the the bounce up still can be transmitted for a large class of states will do some restriction, but is.
Daniele Oriti: reasonably robust the I have difficulties in comparing directly with delicacy, because I don't know what the particle number is equal to see because you know to see you don't really come out of the.
Daniele Oriti: cause greening of our larger she the spacing which has something that counts, because in freedom, you constraint.
Daniele Oriti: But any more precise comparison would be very, very useful.
Parampreet Singh: can ask the final comments will be one harder.
Parampreet Singh: And oh so you're looking you're not like you and I think yeah well, you also mentioned that first thing that the differences between the dressed and the hybrid are only in the bounce region.
Parampreet Singh: I think that probably is zoom's a standard acoustic only because if you have this team and regularized ml QC one, then the plank regime extends all the way.
Parampreet Singh: To the far contracting branch, and then we have shown that there are very strong differences between the dress on the hybrid approach all through in the contracting branch not just about EG.
Parampreet Singh: Does the first thing second thing Yvonne you mentioned that when you were discussing these different hamiltonian switch, we cannot agree, and so on.
Parampreet Singh: that the post bonds agrees again that assumes that the post bounce.
Parampreet Singh: universe, is very simple, that there is a single bonds and the universe never went through different cycles, we have recently shown that the universe ventura the cycles, before getting into the inflationary stage.
Parampreet Singh: Then in some of the models, like the like watch that board and Lindner give you will never get the most points universe like ours, so it will be stuck.
Parampreet Singh: In the blank energy, I have just a final question to both give me one like if if i'm allowed to ask, I think, like it's very both of you again very, very.
Parampreet Singh: Beautiful talks with via scobie i've stated very carefully, but I think the one question which which I would like to see in both the toxins that yes, we can have fine tuned initial states which which can which can probably explain the anomalies and.
Parampreet Singh: observations, but I think that is not the only thing we should be satisfied with what we have to ask is, do we have a unique signature coming from quantum cosmology which nor the bouncing model can have.
Parampreet Singh: or no other model of the universe can have, and that is what i'm worried about because in both approaches and me both approaches have are essentially like.
Parampreet Singh: Quite seen like and the point is like in any approach of course magical perturbations in a QC which has been done, like by the time we start asking questions on.
Parampreet Singh: What is observed, but we are already outside the quantum machine the quantum effects will don't matter, except that the background, has to be the wanting one.
Parampreet Singh: So the signature the signature of the real quantum geometric effects are already lost by the time we are asking about the relevant wavelengths which we can see.
Parampreet Singh: And observations I think like i'm not sure whether he won he won in your paper on long gosh entities, you had made certain assumptions about the answers for the bouncing more of it was not exactly.
Parampreet Singh: What one will see from a QC, so I think like I would, I would like to get input from both of you like, what is your thinking like do we.
Parampreet Singh: We I think we all agree that we need very fine tune states to describe certain features of the observations, but.
Parampreet Singh: Where is the hope, or where is our agenda for trying to extract really unique prediction of a QC compared to what, for example, Brendan burger is doing or other people will between.
Parampreet Singh: they'll say once you have a bounce they will say once you have a bounce, irrespective of where it comes from, and I take your initial states, I will get exactly the same results.
Parampreet Singh: So I think that is why what Guillermo said that the initial state has to be motivated from quantum gravity becomes really important.
Parampreet Singh: So any comments, yes.
Guillermo Mena: When do we want to replay first oh.
Ivan Agullo: Yes, yes, again, again, thank you, thank you for for bringing all these points, because you know our time is limited, and we had you know, a limitation of the on the amount of messages that we could, so thank you for compliment in.
Ivan Agullo: All that I agree with most of what you would you have said and and and then.
Ivan Agullo: Now that we have you know, several our predictions or or we know how to move from theory to predictions, both for the power spectrum on oceanic the anomalies etc now, is where we can ask more refined questions as the one that you are asking, can we.
Ivan Agullo: You know single out something which is unique for milk, you see.
Ivan Agullo: hey, by the way, this question has been posted for not able to see, but for inflation itself, there are many models and people were asking.
Ivan Agullo: Is there you know something that only this model can predict, and the answer revealing inflation is very difficult.
Ivan Agullo: difficult because you know, the amount of physical processes happening, since the early universe until now are huge and most of the information is washed out so so we've been an inflation that question is is difficult inaccuracy can we a single out some prediction and.
Ivan Agullo: m barbies you know part of the answer is, this was the year most senior massage this newest scale that ltc introduces which is not interviews by by other models.
Ivan Agullo: on which you know that he said, changing the power spectrum deviation from a scaling Barrio and if you ask me, can Can I make a model to mimic that probably yes, you know.
Ivan Agullo: It is very difficult to find an upsell bubble, which is uniquely you know it's like belly inequalities can only be true if if you know if quantum mechanics.
Ivan Agullo: In this case, something that is only true if you see through either know if anything like that and I don't know if.
Ivan Agullo: We have made that is impossible, given the complexity of the system and the amount of physical processes happen.
Ivan Agullo: On the way, but these are the important question that we all keep in mind, we will change things see you know hold the predictions change and and keep an eye on on this very interesting question.
Ivan Agullo: just keep in mind to summarize my answer that that is a question on the table for any single a scenario of their universe and he's a very difficult difficult one.
Parampreet Singh: Thank you want.
Guillermo Mena: me to be the first thing is that, in order to unify the descriptions I have started, always in the bounce Okay, assuming that any initial condition compete with faces initial conditions.
Guillermo Mena: Just because, otherwise, you have many different possibilities important point was a in my last message that they.
Guillermo Mena: In fact, I agree with you that age, they choose a vacuum that we do has to be based on principle okay it's not that we choose a state that is as the offset our spectrum, this will not be satisfactory.
Guillermo Mena: Then the thing is essentially what he was saying about the one to escape a in fact in the literature of the funder cosmology will see a spectrum which this professional viewers.
Guillermo Mena: What I have called the inflationary scale and others in which is in the quantum to escape they they former once I would say that are not capable.
Guillermo Mena: to encapsulate of capture the quantum effects so from that point of view, we will not be satisfactory to to establish look smaller, they will be like a general relativity certainly.
Guillermo Mena: So in this aspect is a positive thing OK, we have some features that are like you simply have look into postman.
Guillermo Mena: And the other important things that this escape appears first even for many of the backgrounds of we can consider if you look under with molly the inflationary still will not be your server.
Guillermo Mena: That is that we.
don't think.
Jorge Pullin: There is a question for for i'm in the chat when I think Western has their hands race.
yeah.
Thank you, this is Carol hi everybody, I have two things.
Independent the first is a question to you, then.
it's a.
appreciate a lot it on your your your synthesis and I was really intrigued by your normal shiny things that you mentioned at the at the end sounds super interesting or something I don't understand is a simple technical thing.
Western: I understand that there's a gaussian approximation, which is just the lead in order in which the two point function sort of determines all the higher.
Western: important functions, and in particular the frequent function is zero.
Western: Now, if you go to next order what happened is that the two point function changes, of course, because you go to make soda so there's a correction and generically the three point functions becomes different from zero because, because there is this.
But now you, you have said something which it was curious about, you said that 3.5 should be become different from zero.
And this has an effect on the two point function in direct that.
That let's say we can measure let's let's say we can measure it by measuring the two point function now do you mean this I missed that I didn't fit with my understanding of the story, do you mean simply it was.
involved way to say simply that to like store the data without your changes or do is really a report function involved in this story.
Ivan Agullo: Thank you Gary so it's a very good question, and it was my fault, because it was very brief and I didn't explain explain the so thank you for.
Ivan Agullo: Let me just say a few a few words about that, let me share my screen again.
Ivan Agullo: What you have said, is precisely the two things that that that may happen, a wine is that you know.
Ivan Agullo: Of course, once you introduce a next to live in order, and if you compute the coupon function, you will have one loop effects which is you know.
Ivan Agullo: Exactly, and that is going to be modified that happens to be quite small, in fact, for for for from from.
Ivan Agullo: You know, using their the paradigm, we have we have us and the effect of that seems to be quite a small and out of of of observation, what happens rather.
Ivan Agullo: is something that is influence in an indirect manner by 30% functions and he's happy top down so so let me try to explain it as clear as I can.
Ivan Agullo: In fact, this is the origin of the the is not mine, it was already a be proposed in the cosmology community and it's called non gulshan modulation.
Ivan Agullo: And what happens is the following imagine you have a three point function.
Ivan Agullo: And, of course, the value of the function depends on the configuration of the three points, if you want of this triangle, I have in mind is like the bending the shape of the three I know the three main function is bigger or smaller.
Ivan Agullo: What happens in ltc is that they don't know shiny these are sad that, for this multiple angles, when the three were the three points feet inside the huddle right they have a.
Ivan Agullo: patch no notion he started small that as long as one side of the triangle X three in my blood gets separated from the other two points that are very active angle gets bigger and squeezed they don't go show me the increase.
Ivan Agullo: So, it happens that these two points X one X two are strongly correlated with X three if actually is is enough far far away from it 100.
Ivan Agullo: And therefore, what happens a you can think about this either, in reality, space or inferior space with K one K 23.
Ivan Agullo: What happens, therefore, is that if we have let me do the argument in your space what is what what what is normally done if you see or.
Ivan Agullo: Maybe, for us, because we are more used to it, what happens is that if you have a third node case 30% in your universe, with very long wavelength.
Ivan Agullo: So you cannot see in the CME because the wavelength is too long it's may present just because this person is gonna buy yes, whatever it happens inside, they have a radius.
Ivan Agullo: Because this is from correlations so the presence of this mode long wavelength mode or is hampson will produce a different power spectrum inside the other writers, because they're strong correlations the CME is very correlated with the exterior.
Ivan Agullo: This is what people call non gulshan modulation, that the presence.
Ivan Agullo: presence of nano sharpies bad, yes, the statistics wi fi now would have a better.
Ivan Agullo: visual effects statistical thing is the percent of something else outside okay that with.
Exactly Oh, I see I got it Okay, thank you, thank you, thank you, thank you, that reflects the second point, if I forget stop me if I cannot second point is it's a it's a comment, I want to make to what the nila said.
Since this is a general discussion and since then either least general point I would like to make the following comment.
The nearest focusing on the effect of sort of the elementary constituents on the large scale phenomena effect that might be.
Important, of course, you know the narrative phase transitions things happening and so like that.
Western: Which it's it's it's, of course, very interesting.
So search problem because he might eat my my lead to to understand something.
So this is not a criticism, or what I nearly is doing, but the way he the nila presented it could be taken as an implicit criticism of.
Any research problem that is regard disregards that.
And, and so the title of cosmology in a certain sense and and and I think this is wrong in the following sense.
When we let me say one thing about classical mechanics one thing about quantum mechanics when you do classical mechanics.
We are not describing the individual constituents the elementary constituents of reality will do the solar system dynamics, we know that Jupiter is made by many, many apples, but that's not the point we.
single out some degrees of freedom, which is the position of Jupiter with respect to the silent Venus of years.
And we find a case because of the configuration of the universe will with this degrees of freedom, I have a mechanical.
behavior that can be captured by some equations and it works, and we do always that because, in fact, we never know what are the elementary constituents, the entire science.
works, independently of the elementary consequence when there are some some degrees of freedom that can be described it can be found to.
To have something radical equations that describe now once we go to quantum mechanics it's exactly the same thing if I had a pendulum or.
mechanical pendulum like the one day they started the quantum mechanics in in in the laboratories now it's completely relevant the dependent was made by atoms.
It has one degree of freedom that oscillator these oscillations called ties and this quantization is measured so quantum mechanics does not is not a theory about elementary constituents is a theory of.
quantum properties of any degrees of freedom largest malls that it is.
This doesn't mean that sometimes it's good to study the elementary considered small constituents to see collective phenomenon, of course.
These are interesting and that's why what the deal is doing is interesting, but not because the large scale degrees of freedom cannot be described by themselves, and if one doesn't do that what is making a mistake, not at all.
And I think we in our Community general generically we often make this mistake, I think that quantum gravity is should not be viewed as the study of elementary constituent of space time.
I think this is a wrong way of thinking about quantum gravity quantum gravity should be thought about the the quantum properties.
of degrees of freedom of space times, whether they are large or small, so if there are phenomena that involves large degrees of freedom large scale degrees of freedom.
This should allow a description.
A quantum discrete john just by themselves.
This, by the way, it's also true in quantum field theory standard quantum field theory, in spite of normalization and everything the way the.
In KC D.
One computes the masses of the particles of the lattice using your CD is this regarding all the degrees of freedom which are smaller than.
say the Cork wave wavelength, so I want to separate in in in this story, because I think it's a it's a common mistake in our in our Community.
Yes, it's interesting to study collective phenomena definitely because something interesting can come out for it, but this does not mean the studying large degrees of freedom bites by themselves for.
it's necessarily wrong necessarily disregarding something.
Jorge Pullin: boy.
Daniele Oriti: Can I can I comment to clarify so.
Daniele Oriti: So, to clarify what my point was my point was not normative.
Daniele Oriti: I mean it's not what is right and what is wrong, what should be done or not.
Daniele Oriti: And the point is, I mean that I want this to be clear, the issue is not.
Daniele Oriti: classical versus quantity.
Daniele Oriti: issue is many degrees of freedom versus a subset or collective variables and.
Daniele Oriti: The point of whether the collective effects relevant or not, the for the factory, then our next word subset to global lower collective observable.
Daniele Oriti: need is in many cases, it is not in some urgency is not there in many others who say, rather than QC do rather take any quantum anybody system, I mean.
Daniele Oriti: There are many systems in which the affected collected and honestly it doesn't really be entered all on the.
Daniele Oriti: Not so much on on collective interactions of the constituents and it doesn't depend march on their quantum nature.
Daniele Oriti: There are many others in which you neglect the is collected effects initial neglect to the quantum nature, he considers you totally miss the physics it's a research question now, in which case when when we because mala g.
Daniele Oriti: And, in general, when we start.
Daniele Oriti: generativity we will continue description terms of fields, so from our quantum gravity models which we have a different type of freedom.
Daniele Oriti: it's not a matter of being right would be wrong with just to be aware of, we just have to be aware of the different limits different types of approximations and we should be able to control them, we cannot declaring advance and what is not relevant, and was not until we find out.
Jorge Pullin: Okay boy yeah.
Abhay Vasant Ashtekar: So I mentioned.
Abhay Vasant Ashtekar: i'm very happy with the last.
Abhay Vasant Ashtekar: Discussions with the blue and Daniel day because the first couple of points, the first point I want to make is really about the continuation of that.
Abhay Vasant Ashtekar: I mean, I think, just just give example along the same lines of.
Abhay Vasant Ashtekar: How long.
Abhay Vasant Ashtekar: Is, and this is an example like you and many times before, namely that we could just take.
Abhay Vasant Ashtekar: Direct model of hydrogen atom, which is very sparingly symmetric and by assuming it's pelican symmetric one immediately says, there are no 14 degrees of freedom.
Abhay Vasant Ashtekar: So in Daniel is language infinitely many degrees of freedom are suppressed by imposition of this spell and symmetric.
Abhay Vasant Ashtekar: And yet it produces results which are perfectly fine so we're lowering all kinds of fine structures, I mean really I mean if anything.
Abhay Vasant Ashtekar: and keep you on the final component and yet until one goes to lab shift, what does not really see any discrepancy with data model, of course, in a logical model.
Abhay Vasant Ashtekar: And in fact you know you and today the rigorous totally rigorous statement of hydrogen atom from phuket cutie is not allowed, but we don't worry about that and so much.
Abhay Vasant Ashtekar: So I think that this is going back to what he was saying that there is also an observational issue here, that we should always keep in mind.
Abhay Vasant Ashtekar: And then, as Daniela just now in fact it's a very beautiful either we it's not each of the classical versus content, I mean it's a question about whether.
Abhay Vasant Ashtekar: When he's doing sort of course grading and whether that is creating big effectual is not creating big effects, maybe not picking the effect.
Abhay Vasant Ashtekar: So in this case I mean, in the context of cosmology except as a note of maybe a lot of people accuse you don't know.
Abhay Vasant Ashtekar: There has been a controversy which has been going on for about a decade now about precisely this issue, namely that we assume Friedman, Robert Walker model may be small perturbation on it and get great success with observations in classical cosmology.
Abhay Vasant Ashtekar: But because it's motivations grow up because of traction but people say well but that's not really true, we should really get this model as.
Abhay Vasant Ashtekar: By about average and that that was a great excitement that may be desiring actually produces a big effect, which is the you know we don't do in need of a smaller constant and.
Abhay Vasant Ashtekar: This is a controversy that has been going on between you know one side is booklet georgiana's Malcolm mccallum and the other side is Bob Walden and green and.
I can.
Abhay Vasant Ashtekar: Sorry.
Abhay Vasant Ashtekar: Thank you, I did not know that.
Abhay Vasant Ashtekar: which was which side is he on.
simone: The side.
Abhay Vasant Ashtekar: Booker Lucas, I think.
Abhay Vasant Ashtekar: So.
Abhay Vasant Ashtekar: So I mean this is.
Abhay Vasant Ashtekar: This is going on, but other than I mean I.
Abhay Vasant Ashtekar: I follow it up some don't do research in it, but i've always great interesting very, very detailed discussion, particularly agree, and also with the GA listen Malcolm.
Abhay Vasant Ashtekar: And I kind of feel that I feel that really it is true that that is perturbations don't have the hidden costs while you don't have any effect large effect.
Abhay Vasant Ashtekar: On one side of more than down and then green it's not sold completely but but I, but at the moment i'm not trying to resolve this controversy i'm just like to say that there is a real possibility that.
Abhay Vasant Ashtekar: That God was hinting at which will actually be realized, maybe, just as we don't have to worry about atoms of Jupiter.
Abhay Vasant Ashtekar: That we would all have to do this, but I agree with with Daniel a that this is an issue that one needs to be analyzed in some detail and then.
Abhay Vasant Ashtekar: And then it's what i'm analyzing but once you're not a priority dismiss the idea that you know that this averaging any growing.
Abhay Vasant Ashtekar: Number of degrees of freedom is clearly wrong, I think one should not say it's clearly wrong, I mean what i'm not saying, Daniel you're saying that.
Abhay Vasant Ashtekar: But there is often a viewpoint that unless we derive everything from lukewarm cry with you from scratch.
Abhay Vasant Ashtekar: Then you know all kinds of new things can happen yeah all kinds of new things can happen.
Abhay Vasant Ashtekar: I mean people thought that about guy which is days, all kinds of new things can happen the full on emerging and still you know very simple ideas, actually, by the way, we would today, so we should skip this mind in open.
Abhay Vasant Ashtekar: I think about the second thing that I had was a little bit more technical, so I think i'll just like to the people, email messages and.
Abhay Vasant Ashtekar: So I think this is the main thing that interested.
Jorge Pullin: me.
Daniele Oriti: Can I can I reply to the comment so yeah thanks for pointing out the the classical situation he is entirely analogous as an ethical principle essentially a matter of whether the cause gleaning.
Daniele Oriti: Much you can neglect the contribution of freedom equals green away in the constraining procedure and, instead, both the technical and no an observational question, then they want us to try and check.
Daniele Oriti: So I won't comment on the classical story because enough, but I can tell you what we see in the in the gst contest.
Daniele Oriti: That you know the hydrodynamic description, in fact, as a as emphasizing, there is no use your near term in the equation that really looks like a quantum cosmological ation and then you've got an India corrections.
Daniele Oriti: Now.
Daniele Oriti: If the.
Daniele Oriti: Fundamental introductions of small us respect in job is corrections and it's not enough terms of to maybe only kind of have that made a time and in fact that's what we find we find out that.
Daniele Oriti: The free term allows you to record with his vision to see like dynamics, with some changes, but you have a ball, so you have the freedmen life equation.
Daniele Oriti: It later times what are you missing so you're not certainly not missing what that allows you to recover Friedman dynamics in this specific context, again, and I want to make a general statement.
Daniele Oriti: You missed the possibility that the naked times this new effects modify the then obviously in ways that the linear.
Daniele Oriti: truncation so the fully dust because green, they will correspond to a quantum cosmology The sad thing is, by definition, not able to see.
Daniele Oriti: At least not in this, you know that way they could be effective ways in which you know you have an effective leaner than armies, including the contribution from interruption but.
Daniele Oriti: that's okay and and that's it that it's all the mvc framework is in fact reproduce for a larger class of regimes and phenomena indeed within and more general contest what we have under some.
Daniele Oriti: Limited control and so that's an advantage to be able to tell if the results of this non linearity so because, when is or is not relevant, and where.
Daniele Oriti: And, in general, of course, I agree with you that there's no statement here or anywhere else that something is right and something is wrong, know that there is a more general procedure, but we will be totally irrelevant for all physical questions.
Abhay Vasant Ashtekar: So just to continue this last last part continue along the thing there's also the issue about the initial conditions that was raised by by Guillermo, but I think, as you want said that these initial conditions issues.
Abhay Vasant Ashtekar: Carbon to.
Abhay Vasant Ashtekar: Everything like classical gender equity wise universe that we live in a very wide wise and huge amount of a nice office today.
Abhay Vasant Ashtekar: That was a.
Abhay Vasant Ashtekar: cosmic microwave background why that you can lie down easy that I don't so you knew what system which solutions nine cents equation, which cosmic microwave background would not have this homogeneity and I sort of see today.
Abhay Vasant Ashtekar: So this is a common question to all fees, and so I mean I think what value they say, also a lot of what people were saying.
Abhay Vasant Ashtekar: Arriving at El que si from full El que je this choice of states are going to be important, and so there was gear was emphasizing, and I think I agree with it, that.
Abhay Vasant Ashtekar: We need some me to be very nice if we have some physical principles which actually give you the state.
Abhay Vasant Ashtekar: And attend that Bradley Cooper and I made was really like like very, very, very simplified coming at a very low level just to open the door, so to say about saying that well put to put together what we know from the kind of guy which has a whole.
Abhay Vasant Ashtekar: spectrum of area and setting to sort of demonstrate that number he constrained by the state of the background, so that constraints, a number of he falls and then use the.
Abhay Vasant Ashtekar: Use the state which is a generalized Rogers Rogers principle that maximum on Virginia and I saw puppy in the blank richie.
Abhay Vasant Ashtekar: And that was really spelled out as to what you want, but in spite of that really careful analysis that was done, the basic assumptions were what they were, and I think they can be improved, improved upon enormously, so my just basic.
Abhay Vasant Ashtekar: suggestion to younger people and so on is that this really is something that one can can be improved and should be improved, because it is an important question initial conditions.
Abhay Vasant Ashtekar: If we can justify them from some more fundamental principles, of course, one might say, by those principles or something else, but if you can I mean what was used in our work was things like uncertainties and very, very basic things so it can be for the improve that will be very, very good.
Abhay Vasant Ashtekar: But I think this is kind of not something that is huge limitation of.
Abhay Vasant Ashtekar: Proper was saying about fine tuning there's not a huge limitation of our approach versus a be anybody else at.
Abhay Vasant Ashtekar: All are you an inflation that's huge fine tuning issue right them in this mainly white bison is back in the middle of something not at the big bang rather than.
Abhay Vasant Ashtekar: Later time but, in the middle.
Abhay Vasant Ashtekar: So I just wanted to conclude by saying that this is really interesting open issue.
Jorge Pullin: or questions.
Parampreet Singh: Can I can I make one comment too.
Parampreet Singh: Obvious come and.
Jorge Pullin: Go.
Parampreet Singh: So I think Okay, I agree with what you have said, but we face another issue and that issue is that our permission approaches a bottom up approaches.
Parampreet Singh: We are not driving the cosmological sector, we have not had Dr the cosmological separate from the quantum gravity.
Parampreet Singh: Therefore, we do not know the perturbations which we are doing as what quantities perturbations over an effective background, how much do they truly capture quantum geometric effects.
Parampreet Singh: So our challenge is much better and and we have an example of a Martin was trying to mimic certain look quantum gravity affects in his support and we know it just failed because it was blatantly in disagreement with observations, so I think like there are certain issues which we.
Parampreet Singh: i'm not saying, I think that there is a huge progress which has been done in automation theory in last 10 years and as you'll see.
Parampreet Singh: Including if each day the negative results from the reformed algebra approach, which we all agree, have serious problems, but the main issue means that instead of this bottom up approach.
Parampreet Singh: What does a top down version and whether this bottom up approach of the fourth one place but patients on effective background.
Parampreet Singh: Does it even completely capture or even partially captures what we expect us perturbations from quantum gravity and the issue of initial status true.
Parampreet Singh: Initial conditions problems is to as one mentioned as you're mentioning but, again, there is a caveat.
Parampreet Singh: In all those approaches, even in GR examples or inflation, they truly used inflationary dynamics, we do not use it.
Parampreet Singh: If you look at it carefully by the time we are looking at the relevant wavelength modes quantum geometric effects are done.
Parampreet Singh: they're gone so we are essentially mimicking some bounce dynamics, with some initial states which anyone can mimic, so I think we have to look at these issues more carefully.
Guillermo Mena: You play fantasy something even again with the.
Guillermo Mena: Three of you have said.
Guillermo Mena: In particular, with a pattern, that it is through a secondary.
Guillermo Mena: effect fact is that we are progressing a lot of the issues that we have to look more carefully but resources, the ones that I have been commenting on this case okay my opinion, it has the right direction to continue obviously Luca.
Guillermo Mena: is telling me more and more readers than what we have is probably a good approximation of it in my last transparency, there was a sentence in Spanish, there is essentially a quotation that has been attributed to don T shirt oh no it.
Abhay Vasant Ashtekar: Does.
Guillermo Mena: not appear in the novel and it says in English, the dogs bark central, this means that we are writing that essentially is a little with a situation.
Guillermo Mena: Where a lot of prominence and to get this isn't we are going in the right direction is because of these that we have these controversial or otherwise no one would care, this means that we have.
Jorge Pullin: Okay.
Jorge Pullin: Colleagues, this.
calexss: Thank you very much it's a pleasure to be here, my question is about if the some connections between cosmology and the other promotions to cosmology Mike reynold cosmology etc.
Abhay Vasant Ashtekar: DC and roscoe smaller you.
Abhay Vasant Ashtekar: would understand.
calexss: Brain words.
calexss: Is there are some connections between cosmology and order approach want cosmology.
Parampreet Singh: If I can answer that question if the question was about the brain world cosmology.
Parampreet Singh: Then in in the in the most popular hamiltonian which we have a loop quantum cosmology if we look at it, effective dynamics, it gives us a modified Friedman equation, which is very similar.
Parampreet Singh: Except that in the render syndrome to brain was it's ro minus row scare by the bulk density the density coming, we have a new role, plus row.
Parampreet Singh: And we have a rule minus will scare, and there was a model by Yuri stand up and warm sunny like in 2001 2002 where they took an extra buying like extra dimension.
Parampreet Singh: And they obtained a similar effective equation, as we get into quantum cosmology.
Parampreet Singh: So the short answer is, if there are two times like extra dimensions allowed in Renaissance from green was yes, you can obtain quantum this multi like equation, but I don't think most string theorists will agree on that.
calexss: It can think of every month, but.
Abhay Vasant Ashtekar: If you just put by hand and make it as a patient.
Parampreet Singh: Do you have to put in my hand.
Abhay Vasant Ashtekar: yeah if you put a negative brain patient than one one would be able to also.
Jorge Pullin: Okay.
Daniele Oriti: Yes, so of course i'm very interested in this show have initial conditions, said that.
Daniele Oriti: I have to admit i'm very confused about how to phrase it within the jury, because the initial condition will be rested to some internal clock and respite to summer.
Daniele Oriti: Is the issue of the effective vacuum state for the nation, so if i'm eating the food Curie first of all I should be fine the background evolution in terms of a traditional clock and then I also have to define.
Daniele Oriti: The local to patients in terms of a set of the physical degrees of freedom that play the role of robots in that case.
Daniele Oriti: So i'll be talking about the choice of ground state or relevant the quantum state for the whole set of degrees of freedom or an input and then looking at how this quantum states behavior for specific values of the internal degree of freedom of users o'clock.
Daniele Oriti: Laura How are we supposed to you know, a struct some effective or semi classical theory for the local to patients and then contest that and see what are the constraints of consistency, for betrothal bottom state that the two things do not seem to be the same at all.
Abhay Vasant Ashtekar: It was the first thing but supplement that the first thing would be the look at the theory and the full thing, of course, is no this little clock so there's no initial condition, but there is a preferred state.
Abhay Vasant Ashtekar: So that's what to wear like this, I don't want to call it vacuum state but there's some preferred State that is singled out in that which is appropriate.
Abhay Vasant Ashtekar: For the physical problem of describing the large scale structure of the universe, so one who writes first other select out the state, and then the question is whether.
Abhay Vasant Ashtekar: Whether the.
Abhay Vasant Ashtekar: They learned better at their existing time clock.
Abhay Vasant Ashtekar: With respect to which the revolution looks like what we.
Abhay Vasant Ashtekar: See, first of all in the post inflation or during inflation era.
Abhay Vasant Ashtekar: In that state and then so that the two three step problem first is single order preferred state.
Abhay Vasant Ashtekar: Similar preferred state in the full period, the second one would be is that internal clock such that.
Abhay Vasant Ashtekar: The dynamics of that state reproduces what we see in the quote unquote non quantum gravity regime inflation onwards, and the third is the robustness with respect to his choice of internal time.
Abhay Vasant Ashtekar: So I think that is a good thing, I think, even if you don't worry about robustness you can succeed in the first two things which will be a very notable thing, namely that does exist before state which is given to you by some general principles and there does exist.
Abhay Vasant Ashtekar: choice of clock which will actually reproduces the universe, we see, I think that would be by itself very, very.
Abhay Vasant Ashtekar: Nice.
Daniele Oriti: But, but then we should not respected, but the first thing is more like a you know some robustness.
Daniele Oriti: of our cluster states, because what, why should he then select the just one stating the food to be.
Daniele Oriti: Referring to for the right reason since it's more like the botanist of the effective than a mixer for some choices stage so with similar initial.
Daniele Oriti: properties since since our initial dynamics.
Abhay Vasant Ashtekar: So the state of the question would be really powerful states which is which but put by first principles, you would like to say that preferred for this problem, so these are the stage which you would call.
Abhay Vasant Ashtekar: A million for as a Tropic there's a class of states and then for them it doesn't have to be a preferred state.
Jorge Pullin: yeah Thank you any other questions.
Jorge Pullin: Okay, if not, to thank the speakers and see you in the call.