Okay very good morning guys it is Monday 6th of July I hope you all had a fantastic weekend before I begin my kind of look ahead for the for the week Just wanted to mention on Wednesday evening as you can see here to the side of me We're holding a webinar between 5 to 6 p.m. London time and it's going to be on the importance of risk management So obviously one of the main cornerstones of any successful and consistent trading strategy So I'll be joined by the head of trading peers tomorrow other guys Alex and Sam will also be on the call, but it's an open invitation the registration link is in the description of this video It's going to be an association with aria trading who have a pretty neat software solution as well regarding specifically risk management Which I think you guys would find particularly interesting So hopefully you can join us that'll be on Wednesday. Do feel free. It'll be capped at 500 people online and via zoom So hopefully I'll see you then but let's talk about markets and what's going on and what's driving things This morning and as you can see a definite case of risk on atmosphere Equity markets overnight in China were up in excess of 4% actually was the biggest one-day Move higher in Chinese equities in a year mid-positive commentary on the market from state media and this comes after last week as well the market there domestically was up 7% The front-page editorial in the securities times basically today said that they're fostering a healthy bull market After the pandemic is now more important to the economy than ever The number of mainland commentaries and retweets containing the term bull market Over the weekend was more than 10 times the average of the past 90 days according to the bidee index So the article in itself underpinning the accelerated gains and stock market reforms and excess global liquidity was the main things that they were kind of talking about so as such You can see this feeling right through into the the kind of index futures. I mean the DAX already up Although it's off its highs. It's still up 262 points U.S. Stock futures obviously reopening after the extended weekend and despite some of the Coronavirus situation impeding some what some of the Independence Day 4th of July celebrations That very much being brushed aside, which in itself I'll talk about in more detail I think is a very important thing the way the market is now perceiving the still somewhat accelerated numbers in North American and Basically disregarding them for the time being So the NASDAQ's up about 125 the S&P up 36 In step with that then although it's bumped up a little bit as Europe has come in gold It's still down about six and a half dollars in the US 10 year down four ticks at the moment, so yeah, it's a very much reflection of that and just generally Confidence in the short term I guess over the situation and led by Asia So how long this just general risk appetite can be maintained today will be interesting to see Because this is very much a China narrative that seemingly has given the markets a bit of a boost So I think when the US starts to come in Returning from their holiday and the situation as they said on the coronavirus nationally there isn't good still The markets managed to look over that for now I'll be interested to see how it performed later on this afternoon whether we get a little bit of Profit-taking on some of the moves that have been seen overnight will be interesting In the currency markets the Dixie's actually come off considerably So it continues to be somewhat tied to general risk sentiment as a barometer almost the Dixie's actually down almost half a percent So it's a really quite an aggressive downward move seen in the overnight session So in the currency pairs in the top left euro dollar and cable both on the front foot the euro In fact, it's up about 60 pips close proximity to the high that was seen towards the back end of last week And you know on the weekly will be continuing to keep an eye on some key upside levels coming in The the weekly highs that we're seeing last two weeks both that pretty much around the same level And then that longer-term trend line going back to 2018 will be interesting for sure to watch for out throughout the week, but let's have a look at Overall some of the headline stories. There is a full technical analysis Video done by Sam that he issued on the amplify trading YouTube channel if you just scroll down to his playlist You'll be able to see that and he'll go over the charts in way more detail from a technical perspective But for me just having a look at then through the headlines. This is as I just described people were looking at the CSI 300 the kind of biggest companies in China and Reporting its most overheated since 2014 after gains continue to accelerate Brokerages reported to be talking about this kind of daily turnover topping one trillion yuan, which is very rarely seen So no, it's this kind of the most amount of activity that we've had in a long time And this is what the chart looks like it probably helps with a bit of context actually This is looking at the onset of the pandemic and you'll remember It was around the timings right at the beginning of the year because this was very much Happening the spread of the virus in mainland China before then we've kind of went into that Second and third phase of the outbreak that moved to South Korea Iran Italy and then beyond So it was happening quite early in this year and that was that first dip that we had When the market plummeted due to coronavirus it was then looked relative to contain before we saw the global spread and then the consequent Pandemic situation develop and that was when we hit that overall low And around that time going into March, but the recovery has been Awesome, just like it has been in all the other global indices, but probably even more stretched in the case of China And as I said the kind of state media kind of pumping it up a little bit and definitely the state Just naturally control over these types of things probably a lot more direct than say other Western developed nations and then continuing to pin it on stock market reforms and excess global liquidity And we've just had this real sharp Acceleration here in the last few weeks as you can see On the point actually of the what they've pinned it on the Natlata Suggestion of excess global liquidity. It was an interesting report that came out Overnight or over the weekend for JP Morgan the US Bank They were basically saying the extremely loose monetary policy will be required for a long time to support growing debt levels worldwide Boying liquidity along with global equity and bond prices So JP Morgan essentially saying this is going to further inflate The market essentially as we continue to get back on our feet economically So it kind of fits lockstep with what the Chinese state media were saying and then Some of the other things that people have been looking at is goldman's have come out with a with a research note as well over the weekend and they were talking about the fact that Essentially, they're still decent risk reward for Chinese stocks not unless US-China relations substantially deteriorate from here But what they're saying then is they're they're supporting their call for being overweight China in a regional context The stocks that appear most exposed to US-China relations are technology companies and ADRs While domestic demand focus consumption and healthcare names should be relatively immune So that makes pretty much makes sense anything tied to any exposure that could be subject to say tariffs on The kind of demand for for import export orders from China sure or anything with American related listing But when it comes to a more domestic focused narrative and companies that are dependent on that domestic story in China Then they should continue to outperform and for those interested if you were Wanting to have a look there is actually in this article You can find on Bloomberg a full name of the actual companies that tend to Underperform and also outperform the actual Chinese companies names could be quite interesting to monitor But yeah, Goldman's also they they have what they call a Kind of meter or a barometer of just generally US-China relations I know this is a bit small to look at on my screen here But I have retweeted it or tweeted it this morning if you want to click on it and have a closer look but it's an annotated Graphic going back to January 2018 when we saw the initial kind of intensification of Tensions between the two nations and that was when we were going through that kind of tit-for-tat process in 2018-19 of the ever-increasing Tariff rates But if you look where we are at the moment, I mean obviously it's been incredibly volatile relations between the two nations through much of 2019 But here after peaking in recent weeks and mid-China planning Not as we've seen now implementing the new security laws for Hong Kong things have dropped off quite substantially In fact and so in that regard they would see it from their specific measurement As being far from the peak of where the most intense tensions have have been in the past And more recently from that Hong Kong situation So yeah, I mean that pretty much sums up really the overnight moves so as I said definitely a risk-on feeling to the open but in my mind This is somewhat a continuation and perhaps I'll be proved wrong but the the driving force of what's helped futures pop up and fairly aggressively I mean the overnight session has been that Chinese story And I just wonder how how long that can last for because typically the markets at the moment are very much driven much more from the US Cut us so it's more US centric And also with the updates on the COVID situation being I think more of a focal point for Western markets than it would be for the Fari. So definitely From an underlying economic situation, I mean, I don't think that China is out of the woods yet on either There's much as some of the recent PMI data that we saw last week has continued to suggest general expansion is returning I just think with a lot of this is kind of a bit of State interventional most talking it up looking to squeeze every drop out of this kind of bull market kind of Ideology and just squeezing it up to what is By some measurements quite an overbought market when you're looking at the the CSI 300 in China at the moment Update then on the COVID situation Let's have a look at things and what are we looking at? And so I thought this was quite interesting actually as it tells quite a distinct story of what's happening globally at this present point in time in the UK we continue to see a decrease in the seven-day rolling average of new cases per million in COVID and That is a positive kind of signal because of course we've gone through the next kind of phased of reopening So if you are out and about in the UK this weekend one of the first times You can go and sit in a coffee shop have a pint of beer in the pub and so on so this is the a real key Mildstone now for getting the economy back up and running But obviously as I've said many times before the next two weeks the second half of this month will be particularly interesting to see Whether or not we start to see a Pick up again of the next kind of second wave of viruses in the UK so the UK for the moment is Is heading in the right direction? Suggestion of control Containing the virus in Europe pretty similar. It's kind of static Kind of plateauing so there hasn't been an elevated second wave despite some blips that we've seen in the likes of Germany Their country still remains in that reproductive rate. It's just slightly below that one level importantly But the two areas that have been growing quite rapidly America is obviously the one that gets the most attention Just given just their demo demographic the size of their population the number of cases is now particularly large and a lot of these states have studied to Reverse if you like the reopening process particularly on the Sun Belt so those southern states In particular The other country down here at the bottom which actual case numbers are much lower It's coming from a much lower base, but it is Australia and you can see the trajectory of the curve for Australia is incredibly steep here at the moment and What's happened here? And this was actually an underperforming market in the overnight trade was actually the Australian market The number of COVID-19 cases in Melbourne Victoria's capital has surged in recent days the state reported a hundred and twenty-seven new COVID-19 infections overnight And that is the biggest one-day spike since the pandemic has begun and it has led for the first time The border between Victoria and New South Wales has been shut in 100 years So they're taking these you know pretty unprecedented Historical steps to try and contain now the movement of people in these highly infectious areas And that is going to have of course implications on the Economic recovery of Australia are given these are quite key areas in that regard So the Australia continues to face quite challenging time at the moment UK and Europe is still relatively positive and the US continues to track in a negative fashion But at this point at a rate of which it would appear markets still are relatively comfortable with at least for the time being From a numbers point of view total cases now in the US nearing on Three million you can see here on the seven-day average. We continue to remain on a fairly steep incline. So I guess over the next Week or two we're looking for where does that plateau? And then on a state-by-state level you can see here the areas like California, Texas, Florida Which have been those key ones and do comprise of the three largest most popular states in the entire United States America case numbers generally are still rising at this point in time and and obviously from a beyond the intraday and Perhaps right here right now. This of course is going to have implications then for the political favorability of the president and this is going to be a real talking point obviously that he'll have to defend and On that note, you've had Donald Trump tweet overnight, of course New China virus cases up because of massive testing deaths are down low and steady The fake news media should report this and also that new job numbers are setting record says, you know He's hitting a lot of things here in this one tweet. He's blaming the virus You know, he calls the virus. It's the Chinese virus It's not it's not a virus is the Chinese virus again looking to disassociate that anything that he's done It's that it's his fault deaths are down and they're trying to link that to the fact that it's testing that then is Making that number look higher and then also talking about that people that the media is Biased in the fact that it's not reporting about the good things like the jobs number that we had last Thursday So it's kind of classic one-on-one Political gamesmanship going on But of course will continue to be monitoring this because as far as the bookies are concerned as far as the average pole of Poles nationally in America Biden still is the favorite by quite a clear distance at the moment So he really does need to get a handle on this and soon and when it comes to Donald Trump That probably means that you know, he's not a passive guy. He's going to be out there being assertive and the aggressor So much more from him to come this week. I'm sure Looking at the actual calendar for this week. It is it is pretty quiet. It's not a great deal going on here And as far as today's concern, you have had some German numbers come out this morning German industrial orders a month a month 10.4 percent, which was slightly weaker than expected But no real impact for markets here You have got this afternoon the ISM non manufacturing So this was the quite unusual quirk given the holiday short week last week Was that normally we would look at something like this ISM figure for the employment component to gauge them better the employment Situation ahead of the labor report on payrolls, but we're actually seeing this after so How important this is? Yeah, I mean, it's worth monitoring I don't think it's going to be a massive game changer to be quite honest But the ISM normally factoring number is expected to move back into expansionary territory Above 50 from its previous 45.4, which in itself should be quite meaningful But again, how long that this can be sustained given perhaps confidence will start to be Dented given the Repickup that we've seen or re-acceleration in a number of these key states in America and the COVID-19 situation So how how much you can buy into just one month reading given that we know in the here and now things are changing quite fluidly I'm not so sure other than that is pretty quiet Tuesday Equally so overnight though by this time tomorrow will have the latest RBA Interest rate announcement rates are expected to remain as they are Going into Wednesday and Thursday again very quiet trade balance data coming out Germany on the latter on a Friday we get Again pretty quiet nothing really major coming out of the US and some Japanese inflation linked data and Italian sovereign debt update coming out from Fitch and Then also the other thing to look out for this week is the the recommencement Of course, I believe it's in London this week is the trade Negotiations or the trade pack or Brexit between that of the UK and Europe But no really massive headlines I'd say on that regard so far seen over the weekend UK national press So that is it. I'm going to leave you with that Hopefully then you can join me on Wednesday The link to register for this free webinar will be in the description of the video if you're watching this on YouTube So just go ahead and register you'll get an alert then when we do go live and a reminder at the time But any questions just feel free to leave a comment and I will wish you a fantastic week ahead. All right Thanks very much guys


the first speaker. Thank you very much. I just wanted to say I mean I think some of you have already been here in the previous school so you don't you know the format but just to remind just to tell the new people who have just come for the first time here you will notice that most of the days there is a discussion session in the afternoon. Now that's really part of the school because many times because the lectures are quite condensed in one hour the lecturers do not have time to you know answer many of the questions in detail. Okay so detailed discussion should be postponed to the discussion session and indeed in the previous spring of schools students have learned a lot from the discussion sessions. In fact sometimes even more than the lectures themselves. So I would really encourage you to attend all the discussion sessions and take part actively. With that I would invite the first speaker Professor Hartman and he'll be giving lectures on the average non-energy condition and care. I guess it's working. Okay thank you to the organizers and to ICTP for hosting this. It's great to be here. I look forward to meeting the students here from all over the world. So please do come introduce yourself to me after the lectures. Please interrupt during the lectures. I'll probably postpone a lot of questions so that we can get through lots of material but don't hesitate to raise your hand or just shout out since it's a pretty big room. Just stop me and we can clarify things as we go. So the topic of these lectures is the averaged full energy condition. Quite big is this big enough? Okay I'll probably start writing smaller but stop me and I'll start writing big again as soon as I remember. Okay so when you learn general relativity you usually come across some energy conditions. They show up in all the GR books that go by names like the strong energy condition, the weak energy condition, the dominant energy condition, the null energy condition, and these are usually introduced in textbooks as ways of proving theorems. They're assumptions about local energy density produced by matter that allow you to say things about space time. So all the facts that you're familiar with like the fact that black holes have to have singularities or the fact that there has to be a big bang if we trace our universe backward or the fact that we can't build time machines, all of these statements about space time, the structure of space time, and what it can and cannot do are based on some sort of energy condition. So these are great for proving theorems but all of these energy conditions are wrong. Okay so they're all violated. The strong energy condition I won't get into too much about what these are since they're wrong. The strong energy condition is just not true at all. It's very a massive scalar field to violate the strong energy condition. The weak and dominant energy conditions are violated by negative cosmological constant. The null energy condition is also wrong, violated that is, but it's in a little better shape so let me tell you what that is. I'm going to pick conventions and this will last throughout the lectures that u and v, null coordinates in Minkowski space, so u is t minus y, v is t plus y, then the null energy condition states that t u u is everywhere positive or non-negative. Of course it's can be phrased covariantly. I'll pick u, u just to keep the notation simple but the statement is that the stress energy density dotted into any null vector would be everywhere positive. So this one is in better shape because it's obeyed by ordinary classical matter. Any reasonable classical matter you can come up with obeys the null energy condition but it's still violated by quantum effects. So let's see why that is. So for example if you have a free scalar field then classically is up to some factor just d u phi squared. The g u u component of the metric is zero. There's no null-null piece so this is just obviously positive classically because it's a square of something but in the quantum field theory t u u is an operator now so it's the normal ordered d phi squared where phi is now the field operator and because of this so the thing the thing inside is still something times its conjugate so it would be positive if it were just that but the normal ordering mixes around some of the terms it adds some new terms to this and this is just not the square of anything anymore. It's easy to cook up quantum states where it's not positive so it's not a perfect square it could go negative and indeed it does. For example if you take a state like the zero particle state a superposition of the zero particle state and a two particle state then what happens when you calculate this you plug in so you plug in for the field operator in terms of a and a daggers you do the normal ordering to pick up some extra terms and you can easily check that in a state like this those extra terms dominate the the null energy the only contribution and can come with either sign depending on how you pick epsilon. Another easy example to see where the null energy condition is violated would be in the chasmur so in the chasmur effect you have two conducting plates and between the two plates there's just a constant negative energy density so obviously the null energy conditions can be violated in that region so again that's quantum effects coming in and you could trace it back to these normal ordering terms. All of these local energy conditions and in fact this isn't just a failure of imagination there's no local energy condition that's true in quantum field theory so all these are violated now on the other hand total total energy is positive in quantum field theory otherwise we'd have a problem it wouldn't make sense it would be unstable so the total energy integrated overall of space is positive the local energy can go negative but actually and this is the statement of the average null energy condition there's something in between which is the statement that taking this null energy tuu and integrating it over a null line u from minus infinity to infinity it's rid of those offending terms this gets rid of those normal ordering terms that led to negative contributions in the scalar and if you calculate if you plug in the the quantize scalar field into this expression then when you do the integral you'll find something that's like integral dk ak e to the minus ikx ku mod square so in the scalar field we've just you can just prove by direct calculation that once you integrate this positive this is a positive quantity more generally we could ask whether this is true in any quantum field theory and that's going to be the subject of these lectures so this is the anac the average null energy condition is the statement that this operator e is non-negative in any state in other words it's it's a positive operator yeah so this is this is a definition so i'm defining the integrated null energy to be e and all i've said so far is that if you if you just explicitly calculate this for the free scalar you can check that it's that it's a mod squared of something and and check that it's positive so at this point this is just an interesting observation that hey we found negative energy but it turns out we don't have to integrate it three times we don't have to integrate it over space we only have to integrate it once so the total energy through this the energy flux on this single null line is enough is enough to get a positive quantity and then the subject and then we're going to try to understand why that's true in general that's the that's the goal that's right that's right so in space time um you know there's in space time over here there's a transverse direction which sort of comes out of the board but we've just picked a single null ray say through the origin and uh integrated the stress tensor along that null ray no not no they're violated no i don't think so they can be constant and they they can be violated in a constant way by a cosmological constant so i think not all right at this point it's just a coordinate i could i could define this in a covariant way by by saying that this is an integral of a null ray of t dotted into the uh we could have an affine parameter here and then dot into the usual normal uh but i'll just i'll just use the u coordinate good so so um this so this condition was introduced in gr and it was a statement about curved space and understanding things in curved space but i'm going to focus exclusively on minkowski space so uh just the state just the question of whether this statement is true already already it was motivated by gravity but already the question of whether this is true in ordinary quantum field theory and ordinary flat minkowski spacetime is already a very non-trivial question about quantum field theory and that's why i'm going to stop um there's a proposal for something that's true in curved space but it's uh but no there's no proof of it so the outline of these lectures um is i want to describe the proofs or derivations of in interacting quantum field theories including strongly interacting quantum field theory in five minutes we did the proof for the free scalar uh and other free quantum field theories were considered in the 90s and it was checked that this seemed to be a true statement but it's been understood in the last few years that this is actually a fundamental property of quantum field theory and that's been understood from several different angles so the different angles are of all causality so this will be based loosely on a paper by me sandpan kandu and amir tijini from a couple years ago the second method and these are out of order i've reordered them for the lectures these are not historically ordered uh but the second method that we'll talk about is holography this will be based loosely on uh paper by kelly and wall from i think 14 although i didn't write down the number uh and the third will be from the point of view of quantum information and this is based on a paper by faulkner li barker and wong from 16 so i'll just come ask me for the for the full references or i'll post some notes at some point so that you have the references uh but they all all of the papers have no energy in the title so they're not too hard to find okay if we're gonna prove the ennec three times then we better have some good reasons to do that so before we jump into it i'll give a few words of motivation about why we want to understand the ennec uh so roughly roughly three uh so first of all this is a fundamental property quantum field theory we're really we're not talking about anything exotic here so as i said we're going to be working in flat spacetime we're just considering general quantum fields so the ennec uh is is a consequence of unitarity the very fundamental property of quantum field theory but it's a it's a uh repackaging of unitarity in a very special way that seems to have lots of interesting consequences it applies essentially to all well actually to all reasonable quantum field theories including everything from say the standard model to to stat mech models like the ising model in fact there are predictions that you can make using the ennec predictions for for quantities in the ising model which were new predictions from the ennec and have been confirmed numerically so these are these are things that in principle you can even go out and test the second reason is the fact that there seem to be so many different ways of thinking about it just in itself is very interesting so uh what we're going to see is that this is related to understanding quantum fields in the highly boosted limit makes sense we're talking about integrating over a null line so this is going to be connected to properties of quantum field theory at null separation and what we'll see is that quantum field theory at null separation even in the strongly interacting case is especially tractable okay so when things are strongly coupled qft is hard but in the light cone limit it's not so bad so for example we usually think of ads cft is something sort of mysterious and difficult and hard to map between the two sides but in the light cone limit everything is solvable it's a solvable limit of ads cft where you can explicitly map bulk and boundary and beyond that um it's a limit where holography is actually even much more general so ordinarily holography is a statement about a certain class of conformal field theories i have the large n and a large gap in the operator spectrum but in the light cone limit uh that's actually not even the case actually holography is essentially just a derivable exact statement about conformal field theory as long as you're restricted to the light cone limit reason and i won't really get into this in these lectures but is a connection to gravity quantum gravity so uh you know it's not it's not a coincidence that the anek was first discovered or discussed in the uh gr community this came from relativists uh it seems to be a fundamental a fundamentally important fact about how quantum fields couple to gravity and uh so it turns out that the anek is essential for for getting things like causal structure and curve spacetime to work it's essential for getting black hole thermodynamics to work uh and is it also underlies some of the more recent work on uh thermodynamic and and tropic and other relations and quantum gravity things like uh quantum focusing the quantum null energy condition various other things that you may have heard about okay so um the first so that's that's uh sort of the introduction and uh the first one that i'm going to talk about now is the causality based argument for the anek and i really want to sort of i really want to start at the beginning um and set up the background here so we're going to spend a while doing that it'll be a while before we really get to uh the argument um but let me just draw a picture giving the uh sort of the strategy idea of what the strategy is uh is we're going to look at correlation functions in minkowski space it's working in real time so this is my minkowski space again and we're going to look uh we can think about four point functions although there could be higher point functions and uh four point functions are related to causality uh because you can think about them as sort of an experiment where two of the operators create some kind of background say they create some excitations here so they create some background and then you can ask whether in that background created by those operators you can ask whether you can send a signal from here to there you can think of some of the operators as a background and the other operators as a probe and then you can set up an experiment to test whether that situation is causal to test whether uh signals can bend out of the light cone in the presence of this background yeah i i don't mean much by it i just it's just words for for the question was what does background mean uh that's we'll get into that um but i just mean in the very loose sense of this is some kind of excitation that this probe has to go through so you can think of this these operator insertions as creating some cloud of junk or particles or something and then this probe has to interact with that stuff uh as it propagates so just in the very loose sense and we'll see precisely what's meant as we go along uh so we need to understand correlation functions and especially uh we need to understand correlation functions in this highly boosted limit so that's going to be the first topic uh and i'm going to sort of start from the beginning and discuss both of these things just general properties of correlators in qft including some things that that that are important but not usually stressed in qft courses and especially focusing on the light cone limit i will mostly assume that we're in a conformal field theory for this for this part one that we're going to be in an interacting conformal field theory most of what i say uh also applies to conformal field theories in the uv that are deformed by some relevant operator uh but it's important that there be an interacting fixed point in the uv since we're going to be working in the null limit uh that's that's a limit where things are effectively close together uh so it's effectively controlled by the uv fixed point and relevant operators won't get in the way but just to keep things simple i'll assume it's conformal okay so the first thing we want to get into for background is properties of correlators in the null limit the essential tool to understand this is going to be the operator product expansion so the operator product expansion uh says that if we have two operators psi of x1 psi of x2 inserted say here uh you can basically that you can zoom out okay if you zoom out if you have two operators inserted and you zoom out on this picture you look at that from very far away uh then you'll just see some local excitation or some local operator rather and uh so that means that you have to be able to at least approximately write this in terms of the local operators of the theory so there's a sum over the operators of co psi psi of x12 i've expanded uh in operators at one of the points chosen arbitrarily but that's not it doesn't really matter which one or where we could expand uh about the center or anywhere else nearby so dimensional analysis already tells us quite a bit about what this sum has to look like so uh on the right hand on the left hand side if suppose that psi has mass dimension delta psi uh then we need the mass dimensions on the right to add up to two delta psi so the only thing that we can write let's say let's say we have a a uh an operator showing up in that sum with a bunch of indices mu 1 to mu l those are the Lorentz indices for a spin l operator then we need to uh contract those indices with something so the only thing available to contract indices is going to be the distance uh the separation x1 x1 minus x2 so there's a x1 minus x2 to the mu 1 x1 minus x2 to the mu 2 all the way up to l what else can we stick in here uh well we need to get the dimensions to add up right and the only other thing we can stick in is x1 minus x2 um the x is the distance from x1 to x2 and uh just counting up dimensions on the two sides we need to get two delta psi that gives us all over the right mass dimensions so now we have to get rid of everything else so there's a plus delta o to cancel off the dimension of this one uh then there's a minus the spin of o l uh to cancel off all the dimensions from these um and finally there could be some constant coefficients c psi psi o so in a general q of t uh this is just the most general thing that we can write the most general sum we can write down that makes sense by dimensional analysis uh i've i've written this last thing as a function uh if there were if you could make if you had a theory with a mass scale then this could be a function because you can make a dimensionless function in a theory with a mass scale by multiplying m by the length uh but in a cft there are no masses uh there is no dimensionless function that you can stick here the only thing you can put is a constant and that constant is the ope coefficient so this is what the ope looks like in a conformal field theory yeah psi here is a scalar that's right but there are two nice things that happen in cft one is that this is not a function it's just a number uh the other thing is that we understand quite a bit about when this converges and when it doesn't converge the statement is not quite often you hear the statement that in in c in cft the ope converges that's true uh under the right circumstances it's true in euclidean signature when there are no other operators nearby it's not true in lorenzi's signature in the kind of situation that we're interested in so we're mostly going to not be dealing with convergent ope's but they still make a good asymptotic series so you can still use them to approximate these operators well sort of uh the anek and euclidean signature is is captured by unitarity which has a euclidean statement that i'll talk about but it's very hard to get at the anek from euclidean signature it's a it would if from the point of view of a euclidean quantum field theorist the the kinds of quantities that will write down can all be stated in terms of the euclidean theory but they would just be they would seem like totally crazy things to talk about in the euclidean theory and they're very natural things to talk about in the lorenzian theory so in the euclidean ope limit by which i just mean that uh we have so let's put our operators symmetrically uh we have an operator psi of u v and another operator psi of minus u minus v the usual ope limit that people talk about is one where we just move the operators in the in the ordinary direction that is we send u and v both to zero simultaneously and in this limit we can think of all of these all these position dependent things here are scaling to zero at the same rate so it's easy to figure out which terms dominate and uh basically there's a x one minus x two to the minus two delta psi plus delta o the minus l's here cancel against the l factors of position showing up here uh so each term comes with distance to this power so the lowest delta o's the lowest dimension operators are the ones that dominate the expansion this is often what makes the ope useful at short distances is that uh if so say say you have a conformal field theory or someone hands you some data about a conformal field theory but they don't hand they don't tell you everything about the conformal field theory they just tell you the dimensions and uh maybe the dimensions and ope coefficients of some low lying operators then you can already get a very good approximation by looking at those operators in the ope what we're interested in is not that limit it's the light cone limit the light cone limit means uh so here's my u axis and v axis again we're going to start with our operators placed symmetrically but now i'm going to take these together in the in i'm going to take them to zero distance but while maintaining a null separation so we can do that by sending this one up here and this one down here this is the limit v to zero uh u held fixed the limit v to zero with u held fixed um we get so the the distance squared x one minus x two squared is just minus u v so we get a factor of minus u v to the minus delta psi plus delta o minus l o over two uh and then what we get for those other things depends on what indices show up on our operator in the equilibrium limit all the different components of the operator we're showing up at the same order but now that which component you're talking which clarence component you're talking about is going to matter so say we have an operator with a bunch of u indices and a bunch of v indices with h of these and h bar of those there could be other there could be other transverse directions as well those won't affect the conclusions here um if we have h of these and h bar of those then that means we get a factor of u to the h v to the h bar from those contractions okay so from this we can see two things and the question the question here is what are the important operators so what are the important operators in the light con limit well um if we have v indices down here then those have to be contracted with v's and we're taking v to zero so one thing we see is that anything with v indices is going to be suppressed the good dominant contributions are the things without any v indices okay so v indices are suppressed and the second thing is that the combination now that's showing up as so we're taking v to zero let's say we get rid of all the v indices then we have a power of v to the delta minus l over two okay so uh the expansion is no longer controlled by the scaling dimension the expansion is now controlled by uh what's called the twist means dimension definition of twist is just dimension minus spin this means that very high dimension operators can be very important in the light con limit as long as they also have very high spin okay so in the ordinary euclidean limit things were dominated by low dimension in the light con limit things are dominated by low twist so what are the low twist operators in conformal field theory well the twist like the dimension uh it can't be too low it can't be too low because uh there are uniterity bounds which say that if things have dimensions that are too small you get negative norm states okay so unitary bound these come from demanding that two point functions are positive and these tell you first of all that scalars have twist greater than equal to d minus two over two where d is the spacetime dimension this is just saying that free fields have the lowest twist so like a free scalar has dimension d minus two over two and a scalar that's not free can only have a twist that's higher than that so it's saturated higher spin operators um have a slightly different unitary bound that just says tau is greater than equal to d minus two and the way to think about that is that the lowest the saturated case tau equals to d minus two is it corresponds to a conserved current so conserved currents have minimal twist and anything that's not conserved has to have a bigger twist so for example if we're in d equals four and we ask what are the low twist operators in the theory well then maybe if we have a if we had a spin if we had a conserved current uh say from a u one global symmetry then um that would have spin one obviously there's one index in four dimensions it would have scaling dimension three so tau we also always have the stress tensor so the stress tensor exists in any conformal field theory any quantum field theory and uh is always conserved so this is something with spin two scaling dimension equal to the spacetime dimension which I was saying is four here so again has twist two uh the lowest twist operators in the theory are the conserved currents uh but we're not quite done there are more because uh we can also start taking derivatives so take a derivative of t mu nu when you take a derivative the spin goes up by one so now now you can make a operator of spin three uh but the dimension the scaling dimension also goes up by one when you take a derivative so delta is equal to five and again the twist is two this wouldn't happen in the euclidean limit in the euclidean limit you take derivatives the dimension goes up those are sub leading in the larancy and limit the the leccon limit uh derivatives and it's of course we can keep doing this d alpha d beta t mu nu also has twist two I'm going to ignore okay so so if we we ask what are the low twist operators the lowest ones can be the scalars I'm going to ignore the scalar operators in the ope we can come back to them in the discussion or people have questions they won't affect anything that I say uh just because they have spin zero they don't uh lead to the kinds of terms that we're interested in and they can all be dealt with but I don't want to carry them around and then and and have to write them all the time so I'm just going to ignore the scalars uh now generically the only conserved current is the stress tensor if the theory is interacting then the only possibilities are the stress tensor and things that are spin one uh the spin one things the spin one currents also like the scalars won't affect anything they'll say we could keep them but I'm just going to drop them so this leads us to a key conclusion which is that dominant contributions count ope as v goes to zero the following operators so it's just the stuff that you can make uh out of the stress tensor and we said remember we said that we wanted things that are low twist and that the v indices are suppressed okay so the the dominant contributions are just t u u and the u derivatives of t u u expand as v goes to zero these are the dominant terms in ope yeah let's see that I guess um since I've only I've only put my scalars in the uv in the uv plane then the transverse directions you can just absorb into so I haven't even written the transverse indices you can just absorb those and those create higher dimension operators so those won't come in yes I'm about to make that comment yeah that comment too yes so oh spin one currents would also be on this list um I'm I'm gonna put I'm just gonna assume that the theory doesn't have a spin one current but it wouldn't affect any of the conclusions that we're gonna reach eventually okay so two caveats which were the two first two questions um this would be false in um a free theory in a free theory uh you can you can make a tower of arbitrarily high spin conserved currents so take a free scalar for example if you have a free scalar you can make operators like this uh that are conserved by the by the free scalar equation of motion uh and this would be a so by by adding terms like this together you can make uh a spin for conserved current and this would spoil this claim so these would also contribute in the light cone limit at just the same order of those as the stress tensor terms but interacting theory uh these conserved currents all go away so there can't be higher spin conserved currents in interacting theory their twist gets increased by the interactions that the other caveat uh is that this would be false in a two-dimensional cft uh the reason for that is a little different the reason for that uh is because the twist of the stress tensor in two dimensions the twist uh is d minus two okay so the so the stress tensor has twist zero and the fact that it has twist zero means that you can make new twist that you can make an infinite number of other zero twist things just by multi multiplying together the stress tensor so you'd also also have to include things like t u u squared t u u to the 10 v u to five t u u etc just everything you can make out of t u u's would also contribute and uh these are also exact all the all the currents that show up in the uh verisora algebra so the existence of the verisora algebra in two dimensions uh is is existence of all these extra twist zero operators and those would also show okay so so far to summarize these words in equations what we said is that as v goes to zero the o p e psi u v psi minus u minus v i'm going to normalize by the vacuum two point function of those operators just to get rid of some factors is approximately one okay i didn't i didn't mention the one yet the one is there because the identity you can also just have the identity operator showing up in the o p e that just always has twist zero so that just always shows up as a one okay so that's always the leading term and then these terms we just talked about so there's um just plugging in all our factors from dimensional analysis we have a minus u v to the d minus two over two u squared some m equals zero to infinity b sub m u to the m du to the m t u u of zero where the b m are some constants to be determined this is just putting this that's just this this sentence here with all the right factors stuck in for dimensional analysis so the leading terms are the t u u's and their u derivatives i'm going to set d equals four just so i don't have to carry those d's around but the discussion is completely the same in any dimension higher than two the answer is just the c's i'm going to calculate the b's in just a second so this is this is the vacuum expectation value on the top by writing since i haven't written any brackets this is anything yeah good yeah okay so to find the b sub m's and this is always how you find op is this is always how you figure out what op's are is you plug them into a three-point function okay so that's kind of the whole purpose of op's is to take uh complicated things like four point functions and higher point functions and turn everything into a statement about three point functions and uh that's how you figure out what the op is in the first place uh the the coefficient this b sub m coefficient is going to show up like if we were to plug this into a three-point function with a t and then take the expectation value then all these terms would show up because of the t t two-point function and in a conformal field theory three-point functions are known so i'll write the formula psi u v psi minus u minus v t u u of u three v three is just a known function which you can look up in various papers and it's c psi psi t or you can just figure it out from conformal invariance c psi psi t to u squared minus two u v to the one minus delta psi over u squared minus u three cubed v squared minus v three squared this is just a known function and uh we're only interested in the light cone limit v goes to zero so we can drop that term you need is the t t two-point function so the formula for that is t u u of u comma zero t u u of u three v three is equal to c sub t over u minus u three to the six v three cubed again this is fixed by conformal invariance c t is just some coefficient is actually it's a very important coefficient uh because c t is very roughly some number of fields in the theory or number of degrees of freedom like if this were a scalar then this would be about one if it were 100 scalars then it would be about 100 up to some factors of pi and stuff okay so i'm not going to do the algebra now but you can imagine what to do next right you take this you take this formula you put a t here and then you just evaluate it and make sure it gives the right three-point functions right i've given you enough information that you can do this exercise and uh you'll find b sub m is equal to 240 over c t times m plus three m plus five m plus one factorial okay so just some number it's completely fixed by conformal invariance independent of the theory in principle we're done understanding the light cone ope this is the answer you take this this and you plug it into that sum and uh you you're you've succeeded so that's the dominant contribution in the light cone limit but it's going to be very informative to resum this into an integral so let me write the answer and then i'll tell you comes from so in integral form the ope formula as v goes to zero is one plus delta psi over c t i forgot to mention that uh c psi psi t is negative delta psi the reason for that is the word identity so the the ope of the stress tensor is you can the stress tensor is related to the generator of conformal transformations so you can go through a standard exercise and derive this this is one plus delta psi over c t v u squared times the integral from minus u to u u tilde one minus u tilde squared over u squared all squared t u u of u and everything else zero it's not it's not totally obvious you could resum this thing into an integral but it is easy to check and that's kind of the best i can that's kind of the best i can do to explain this formula is that you can so you just take this formula and you expand t in derivatives and you just tailor expand t around zero then the the uh integral then order by order you do the integral it's totally trivial just this kernel times powers of u tilde uh and you could just check that that gives the right that that gives the right thing okay so this is just a statement that this integral against u tilde to the m gives you the right gives you the right coefficients okay so that's exercise two check that this gives v sub m to actually find the formula just sort of requires some guesswork you can just try plugging in an arbitrary function there expand both of them in tailor series work out the first free orders look for a pattern and then try to cook up one that works that's kind of how to how to come up with that okay so we're almost at the main conclusion for today uh but we're going to take one last step to reach our main formula which is that now we want to consider a double limit which is the limit v goes to zero followed by u goes to infinity this this limit is not done together it's done consecutively so first you take v to zero then you take u to infinity or uh in other words you're working on a limit where v is much less than u inverse is much less than one in spacetime that just means that first so we had our two points first we took the light cone limit so they're sitting practically on on the light cone here but then we're also going to take them to be far apart in in the u direction so we're sort of in a limit where they're sitting on the light cone but they're sitting far apart you can kind of see what this has to do with the experiment i i outlined in the beginning where you want to you want to try to throw a probe through some stuff this is kind of the kind of the limit you're talking about right you're you're throwing it very fast so it's a no limit and you're going to look at it from far away so that's widely separate so in this limit we can just look at that formula here and what happens is that the kernel just drops out right so the as we take u to infinity the limits of the integral just go to infinity the kernel just drops out and we see our friend the null energy operator so the formula is now psi u v psi minus u minus v i won't write the pre-factor again is one plus delta psi over ct v u squared times curly e where curly e is the integral du for minus infinity to infinity t u u of u v equals zero transverse direction set to zero so that was in purpose of this discussion and now you can start to see where the why we might hope to be able to derive the average null energy condition by looking at correlators in the light like limit it's because it really is just the first opera it really is just the most important operator the null energy operator is the most important operator in the light cone limit in this double limit which is limit relevant to doing these this causality test so we'll do the causality test tomorrow and derive the statement that this first correction must be positive and that'll give us the anac so we'll continue with that in the next lecture okay thanks


Hi guys, I'm Brian Sacawa, you're watching He Spoke Style and as promised, today we are doing a giveaway with Scentbox. So the giveaway itself, the prize is a six month single cent premium subscription to Scentbox. So you'll get an atomizer of one fragrance that you choose per month. And remember one of the great things about Scentbox is that if you don't like the fragrance that you've chosen, you don't have to wait till the next month, you can just send it back and choose something different to try out. So in addition to that single cent premium subscription, you'll also get two fragrances that I personally pick out for you. All you need to do to enter is to go down to the description and click that link that we have there that will bring you to a landing page for the giveaway.  So all the details of the giveaway, including how long it's going to be going on and when the winner will be chosen are down below in the description. So good luck and stay tailored.


What's going on infinite family? Welcome back to another video. It's your girl Janice. If you guys are new to the channel, make sure you hit that subscribe button and join the family guys today. I am going to be pranking Isaiah. I'm so freaking excited.  That was so like freaked up. I didn't curse. I was gonna curse, but I'm working on it. I'm working on my, my cursing. So I didn't, I didn't say nothing bad. It was freaked up. It was messed up. It was savage and it was very diabolical. My kind of, my kind of prank. I should be pranking him like that. So guess what? I am going to be getting him back with the ultimate revenge. I am going to be telling him or hinting that his is too small for me. I'm gonna be like, yeah, like it's too small. Like you need to do better. Like you maybe you need to get something to like extend. Yeah. So I'm really excited for this prank. So I'm going to call him up to the bedroom and I'm basically just be talking my ish like I do best and we're going to get his reaction. So if you're ready for today's prank, don't forget to smash that like button. Comment down below team Janice and let's get this banger. All right, y'all. So I just told him to come upstairs so he could do laundry. So we're about to get it crack up. Let's go. Damn. You're gonna put a dent in the door. All right. Now if all of that fell, you're going to pick it up. I don't want to do this. Well, we have to. We have to do laundry. Bro, nothing. Don't they have people that come and do this? Yeah, I would love for somebody to do our laundry, but I just felt weird. Like people coming in and doing that. You know what I mean? Damn. What? It's poking. Wait, you see this? Then it's like, this is a dream. I would take it out. Oh gosh, we have some. Babe. All right. You're going to literally like suffocate me while these little foes. All right. I'll see you. I'll see you when I see you. No, no, absolutely not. Look, I hope I'll put this back in the laundry room. Get back in here. I'll put this back in the laundry room. Hurry up. You better come back. I'm not coming back. Yeah, you need to. Bye. Look, let me know if you need help. Okay. Babe. It's like, no, you better help mommy. He's eating. It's actually not that much clothes. She has not that much clothes. It's not. We just have like sweaters and stuff. Bro, these are like. What? It's just sweaters, bro. You're like, this is like policy.  I'll do anything else. You want, I'll paint the whole house. Like I just don't want to do this. What is this stain? Look at this. What is this stain? What is this? That's yours. That's what's in my oil change. Oh yeah. That's right. So that's those stains. Those stains stain. Bro, how do I get oil on my back? Like you have stain in your little panties? All right. What are you talking about? Stop calling them panties, bro. They're like regular boxer briefs.  They're not little and they're not panties. Bro, stop saying that. Little panties for your little swimmer. Yeah.  It'd be like this. Little swimmer. Yes. Little swimmer. Like it'll be making you go crazy. Little swimmer. It don't.   You were such a liar, bro. Bro, I am not like. If it were little, then how come it always gets the job done? Um, I began this job and I'm not too. Bro, how? How does that make sense? Because I'm just saying like sometimes I just need a little bit more. More what? Babe. More what? Don't lie. You know it's not that big. So don't even try to flex. All right.  It is. It's above average. I mean, it's not micro, but it's like. Micro. It is not small. Yes, it is. It's above average. I googled it. It's not above. I googled it. You googled it? I googled it. Did you know the average size is about five and a half to six inches? I'm well above that. Well above that. No, you're not.  It is small. I need more than that. Like, babe, babe, why are you getting offended? It's small. I'm like, no, it's not. It's fine. I still love you. How is it small? Because it is. Sometimes you say it hurts. So how is it small? Because everything hurts when I have endow. Like, did I have to do it? Man, stop. Just stop. I'm serious. That's the symptom of endow. Like, hello. That's the biggest symptom. Uh-huh. Whatever, bro. Babe, stop getting offended that your thing is small. Like, it's something. I just want to know. How is it small? That's all I want to understand. Babe, it just is. If it's well above average, might I say well? It's not. Gas yourself up.   I just said. It's literally miniscule. Like, it's so small. No, it's not. Yes, it is. No, it's miniscule. Yes, I need something more. Like, I need more. Like, you need to go to Dr. Miami and do something with that. What is he going to do first of all?  What is he going to do? Oh, give you a little bit of an extension so I can actually feel something. Bro, there's no such thing. That is a myth. It's not a myth. It's a myth. You know why? Why? Because one of my boys looked it up and he figured that out. What are your boys for you? No. My boys, because like I said, I am well above average. See, I would tell you, but I don't want you to look any different. So I'm not going to say that. I don't even care about nobody else's few people yours. Like, it's fine that it's small. It's amazing. It is. Bro, if the average size is five and a half to six inches and I'm well over that, explain to me how it is small. Anything below five is small. 100%. That is embarrassing. I am well above that. Bro, there's no shame in my game. I know my caterpillar and I know it's worth it. You know how small caterpillars are? Like this small. All right. So what do you want me to say? A conda? A python? If that. What do you want me to say? You're like this. No, it's not. It's the size of a big grape. Like a cherry tomato. Like that. That shape is weird. Stop comparing it to that. It's like the size of it. The cherry tomato is like this little. Yeah, that's about it. Let me see. Yeah, that's about it. Let me see. You're getting so offended. I'm not getting offended. I just want to understand how it's small. It is not small. Okay, I'm just saying that I need more. That's all. More of what? If you get enough. I don't get enough. Bro, it gets the job done and sometimes you complain that it hurts. So please tell me how you need more if you can't even handle what you're already getting.  I'd be faking it. Yeah, right. You'd be faking it. I just don't want to like hurt your ego but at this point I need a little bit more. Yeah, uh-huh. Whatever. I'm so serious. Like I'm trying to have a serious conversation with you right now. All right. Well, Foley's closed by herself.  Your thing is small. Bro, then Foley's closed by himself.  No, bro, why are you getting offended? I'll pay for it. Like I'll pay for what? An extension. I don't want an extension. There's no such thing as a myth. Well, you need it. No, I don't need nothing. I'm good. I'm good. I will show you right now how I don't need it. Yes, you do. Yes. You get nothing. You get nothing. You get nothing. You get nothing until I'm over this. I'm sick of that. Said it's small. It's minuscule. I need an extension. I'm not having that, bro. You do need an extension. No. When you're off that, then I'll come back and help. Come on. Let's take a trip to Miami. I'm not going. What are you eating? Give me that. Oh, God. What are you eating? What are you eating? What are you eating? Is that kebub? What is that? Nene.  What?  It's not a stable environment for me to eat it. Come on. Why is it not? Nene, we're not safe here. Let's go. Because you don't like any pranks? What? You said what? Yeah, you're definitely folding this virus. Yeah, now what? Get your picture. Do you see this iPhone? We got that. Do you see the iPhone? What? This iPhone is roughly six inches. All right. All right, y'all. You're right. Guys have measured and compared to their phone or a TV. What? If the iPhone is bigger. If the iPhone is bigger. If your phone is bigger. Bad shot. You don't have a problem. I'm out. Bro, he's mad. Like, he got something to prove. I do. We got to say nothing. We got this W. Team Genese is a winning team. He got more press than I did. Whatever. Yeah, go cry. That's it for today's video. Comment down below, Team Genese. And I'll catch y'all in the next banger. Because it's going to be soon. Because he stay pressed and mad.  All right. Whatever. Yeah, go cry.


In ancient Greece, Socrates was a reputed philosopher, we all have heard about him, read about him. He was very knowledgeable and wise man. One day an acquaintance met this great philosopher and said, Do you know what I just heard about your friend? Hold on a minute, just hold on said Socrates. He said, Before telling me anything, I would like you to pass a little test. It is called triple filter test. It is called the triple filter test. Triple filter, that's right, said Socrates. Before you talk to me about my friend, it might be a good idea to take a moment and filter what you are going to say.  The first filter is truth. Have you made absolutely sure that what you are about to tell me is true? Asked the great philosopher. No, the man said actually I just heard about it and thought of sharing it with you. Well, alright said Socrates. So you don't really know if it is true or not but yet you want to share that information with me. Now let us try the second filter. The filter of goodness is what you are about to tell me about my friend. Something good? No, on the contrary it is something not good. So Socrates continued, you want to tell me something bad about my friend but you are not certain about its truth. Well, you may still pass the test though because there is still one filter left out of the three. The filter of usefulness is what you want to tell me about my friend. Going to be useful to me in any manner? No, not really replied the man. Well concluded Socrates, if what you want to tell me is neither true nor good or even useful then why tell it to me at all? This three filter test my friends is most relevant in today's time.  So be prudent and apply this three filter test before believing any information or gossip which is shared with you. Have a great day.


I've always been interested in photography. From the time I was a little girl, my grandmother had portraits, photographic portraits of family all over her house. And she had one room, floor to ceiling, wall to wall, dedicated to pictures of people. And that's what I was drawn to in photography. And I used to spend hours and hours looking through photo albums, loved it. But I never really thought about doing it. And then as I got older, life got in the way, I did all these things. I was interested in art, took some art classes, did art history. And I discovered photography for myself when my husband left me after 25 years of marriage. And it was the one place that I could go where the rest of the world disappeared, the dark room. I applied to school again on a Pell Grant because I was supporting myself and my children. And I got the Pell Grant, I went to school at Appalachian State University in Technical Photography. And then I ended up moving back to Maine to be near my parents as they were getting older. And I applied to the Salt Institute for Documentary Studies because I did not want to give up what I had just found. And I was accepted and went through the program there. And I went from doing fine art photography to doing documentary photography. The show that I'm doing is called Stiletto Life. And I'm fascinated by stilettos because I cannot wear them. I mean, the idea of it hurts my body just looking at people in stilettos. But I love them. I love the sculptural aspect of them and the artistic side to the way they're created. And so I started taking pictures in stilettos. Everywhere I go, it's one of my little projects. You put on a pair of shoes and it does change your attitude.  I have one call, Let the Meat Cake, which I took in Versailles outside the gates of Versailles. I had just seen the whole place and Marie Antoinette was alive in my head. And I walked out the door and there was this woman with these shoes and these pants. And I thought, Let the Meat Cake. And the John is a picture of a woman on the toilet. And I just the idea of, you know, on these balancing on shoes is quite fun. The Kentucky Derby is more about shoes and hats than it is about horses, I think. I really do. And I'd always heard about the hats.  But I started looking at the shoes. The shoes were much more dramatic than the hats. And I'd always been looking up and I started looking down. And I have a whole, you know, slew of pictures of Derby shoes. There's a sign and it's called shoegasm, which, you know, it says it all I think about people and their shoes. And I stole that sign in New York City. I was just walking about actually taking, looking for shoes and there it was. I thought, okay, I was meant to be on the street with that sign there. I didn't know about the store, but I took the sign and it fits. There's one called wannabe.  And dressing up is part of that. The little girl is my granddaughter, Laila, and the shoes were her mother's wedding shoes and she loves to wear her mother's shoes. So she put them on and not only did she wear them and walk in them, but she had this little attitude that sort of came with the shoes, with the hand on the hip.   And it's a bride hiking up her dress and marching through Luxembourg Gardens with her intended or just married significant other. And a slew of people following them and the photographer. And you can just see her, you can see her stilettos, but you can see her pants rolled up under the dress, a pair of jeans. And I just thought it was so fun seeing her parading about in the garden with this beautiful dress and her jeans underneath and her stilettos. As we were walking through the museum, I saw this couple and they were quite involved in the art. But I looked down and she had on these stilettos. And I think walking all over a museum, you know you get museum exhaustion. And I thought my feet are always hurting at the end of a museum trip. And I thought, how can she do that? How can she spend all that time on those shoes, animated and moving? And I just, I just call it the met. When I frame a piece, when I do the composition, always, it depends on what I'm shooting. And a lot of these pictures that I have here are one, I just like that. I kind of have been doing it a while. So I kind of know the way I want it to speak to me. I was always a little afraid of digital. People of race, they delete digital. In the dark room, when I used to work in the dark room, you don't delete anything. You've got it all there in a contact sheet. So even though you choose one and the rest of it, you go back to it a year from now. And there's that picture that you never even thought about. And it's sitting right there looking at you going, what about me? And that's, you say, yeah, I've been waiting for you, where have you been? And so I don't delete any of my digital images because I've gone back and there are probably four or five in this show that I would have deleted. Background's always important to me. I mean, when I, I consider myself basically a portrait photographer. So these are portraits in my mind. And, and I like, I like textural backgrounds a lot. And, and when you look at these images, you see a lot of texture in the background. And also the toenails. I mean, when you've got open-toed stilettos, you don't just put your foot in there.  And there's one called Herringbone that is absolutely one of my favorites. Because, I mean, it just, how did they do that? I don't know, I don't get my nails done. And, and it's just a fabulous little shot of these great nails. But underneath you can see this little edge of red. Because I think she had red nail polish under that. This is a fun project and it's something I can do anywhere. But I also tend to like to do a little more depth in the work that I do. The last picture is called Ouch. As a woman, her foot's out of the shoe and it looks red and sore and it makes you go, ouch. I want to transition beyond that into what happens to your body when you wear shoes like this. It's not a natural position to be in. It causes sway back and all that. So I'm hoping to speak with some podiatrists and some orthopedic doctors, some chiropractors and take this to another level.


So today, when you head on to create a kind of a jithub, it says like a kind of. In the first talk, he mentioned about jitlab. So it's same like if you cannot post on public server like jithub or something. So you can actually have your own server and deploy the jit and use it with that thing. So... Okay, so about me, I'm back in developer in fastercash. So fastercash has been... Promote means you can transfer money through social channel. So you can transfer some person on your friend if you know someone on WhatsApp or if you know someone on Facebook. So you don't need to know his complete bank account details. You can directly transfer using our fastercash product. We actually deal with the partnership with some banks or vendors which actually transfer money and then on top of that we use our APIs to allow them to transfer money across social channels. So I'm back in developer in Java but part-time also do Android development. In my part-time I've created ecobullet.com which you can mirror notifications across devices. So if you have used pushbullet or heard of pushbullet, so through pushbullet you can transfer, means you can mirror your notifications from your device, Android device to your system but using ecobullet you can mirror your notifications across different devices from Android to Android or Android to iPad or something like that. Then some of that apps like toralo which you can transfer money on, I mean sorry, you can transfer money through your Android watch or time-loading an app like that. So those are my free-time projects you can check out sometime. So actually before moving to the handout of how we actually create a JIT server we'll know a little about what's there. So the main motive behind this presentation was we obviously can use JITLab or something like that but if you know something deeper, means you know basic about it, then it's easier to grasp things, that's what I feel. So if you know something, okay, this is how it works. So in one of our presentations previously in this meeting, we had a discussion about what's inside TorchJIT folder. So if you know already what's inside JIT folder, so it will be a bit easier to understand how the, how JIT works. So same way we'll go how actually a JIT server looks like, how we can create one. So it will be easier to use third party tools like JITLab or anything like that. So starting with that, so if you have a remote repository, it's mostly a bare repository. So we have two kinds of repositories, one is bare repository and other is non-bare repository. Non-bare repository is the general repository is what you guys worked on. So in your local machine, you'll be having this, where there's actual working version. You'll be committing your files, you'll be doing your stuff. So that's like a non-bare repository or you can normally call out working repository. And the other one is bare repository where it's mostly for a server side means keeping the JIT content at the server side. So if you technically it's, if you see in your repository in the local, you'll find TorchJIT folder. So basically not this bare repository is that same content in directly inside the folder. And usually you see they, when you create a one, it will be having like dot JIT extension. It's like just a convention if you follow. So same way like if you want to create a new bare repository, it's JIT added dash dash bare. Or if you want to clone some other repository and create a new bare repository, you can directly call JIT clone dot dash bare in the URL. So if we can look at how it actually looks like. So if you want to create, so you can go inside it, test the JIT, in the tool JIT. So you have to initialize the empty JIT host tree. And if you do else, you will see the files which you usually see in TorchJIT folder. These are all like head, branches, content. So obviously that's why we keep it like that, because if you are pushing to a bare repository, then there will be no chances of conflicts because there's no working copy there and in this dot bare repository. That's why they usually, means it's recommended that you always push to a bare repository. And actually we can JIT clone also the same. So we have cloned this empty repository. If you go inside it, if you do else, there's a dot JIT folder. And if you look it inside that, it's exactly same what was there when you created one. That's the major difference between a bare and a non-bare repository. So even after that, we can look at what are the protocols we can use if our bare repository is at the server. So what all protocols we can use and clone it in our local system. So we have like local protocol directly. So you can access a file, means access a repository directly. So like what I did, I just create a new bare repository and then I cloned it there itself in the local. So it wasn't like any server. It's directly at the local mounted hard disk. So that's local protocol. So if you can use it, if you have any mounted or a particular location, means which you can access across the teammates, so that you can go with the local protocol. Otherwise, there's HTTP protocol. So HTTP protocols is... So this SH protocol is little tricky because you have to create this key gen and all, and then you access with that. Definitely there are a lot of benefits of using SH protocol, but with HTTP, you can directly enter username, password, and access your repository. And those username, password also, you can store in some key chain or something. So you need not have to enter those basic authentication passwords. Plus, HTTP protocol is like the same URL you will be able to access on your browser or something, which will be same, which you can use for the cloning of a repository. So that's HTTP protocol. Then as such protocol, it's usually used when you are having your own repository. Plus, because if you have a remote server, definitely you will be having access of SH to it. So you can directly start using this SH protocol. And JIT protocol is... It's more or less similar to SH protocol, but it's not authenticated. So it means it's mostly for public repositories. So same, we have this local protocol where you can directly JIT clone any particular location and work on it and then directly push. So if you look at this one, so the origin is directly a local path, user, fastercast, as taught it. So same HTTP protocol, it's very similar to SH and JIT, but it runs over HTTP basic and you can have your basic authentication that then have to set up the SH keys and all. And the pro is definitely it's single URL for all different type of access and it's very fast and efficient, but it's little tricky to set up. In this actually, XSize will be creating a repository where we'll be accessing through SH protocol only. We'll be using this one. And it's common because mostly if you have any network, SH probably will be already set up. So it's easy to access and secure. And the problem with this is you cannot have anonymous access because each one will be having his own SH key, public key and so you will know who have access it. This JIT protocol is they have lack of authentication, difficult to set up. And it requires <IP_ADDRESS> port to be opened and which mostly cooperates firewalls like Don Sup, means they have mostly closed it. So we'll set up a JIT server and JIT PAP. And previously actually I was thinking of giving on EC2 instance AWS, but then okay, it will be unfair for Google. So I plan, let's do it on Google Cloud. So yeah, so we can start to go on the terminal. So who all have worked on, means used Google Cloud? Okay, Google. So actually I encountered it's even easier than EC2. If you create a new instance and all, it's very developer friendly. And so I've already logged in. So this is how the Google console looks like. You have lots of cards here. And what we are interested in is compute engines. So we'll start with like, from starting, we'll be creating a new instance. Let's create a new instance. We can give any name, let's be instance three. Zone is also fine. We can choose. We can go with the cheapest one, which is micro. So when you actually register with Google Cloud, they will give you $350 free gift. So you can definitely go check how Google Cloud works. Then we'll instead of boot this, we can go with probably 1 to 16.4. Is it visible? Then for now, let's not allow HTTP traffic. But once we have, once we'll go to JIT WAP, then we'll go come here. And we can, means we can always come back here and change the settings. Okay, let's allow the HTTP traffic for now. You can add keys. So if you, so we'll be accessing it from here. So your keys, public key will be inside .ssh, this IDRSA. So you can, you can directly give it here that I'll be accessing it from this key. And let's create it. Plus Google Cloud provides with this GCloud shell SDK toolkit, you can say, which you can use for login to your clouds or creating new instances or anything through command line. So as I've already added my public key to this instance, I'll be able to log in directly. So do we have JIT here? Yeah, we have JIT already here. So we can create a new repository like JITemo.kit. So by convention, we'll follow the same .kit. You can log in to coincide it, JITemoJIT. We'll create a bare repository here. So we have, we are ready with our server. So let's see if we can able to access it from my local machine. So it's a JIT clone. So if you see, we already have JITemo up and running. So congratulations. We already have a server ready with our remote bare repository. So now we can, so if you see, we have our remote is through this IP and JITemo.JIT. You can always create a new readme file. So we have pushed to the new instance. So now we have ready with one user, which is my local system and our report server. But if you have to give it to, means definitely there will be a collaboration, right? And there will be multiple people working on it. So there are two ways you can actually add this. So one is you, like I added it here, my public key. So you probably, everyone will be knowing like how you'll be creating your public key, like normal SH key gen. It will be asking for your default location you enter. You already have exist. Then enter passphrase. Okay. And same process. Okay. So if you, what? Yes, we'll figure it out. So we'll have to add it again probably. So cat. So we can always add it again. So we can go add it, delete this one, add this one. So same way. So I have another instance also. So like search, probably I've deleted it. So basically, so you added, you created this key. And instead of going over there and add it like manually, you can always go inside here, ls.sh and known authorized keys. So you can directly add those keys here, and the other people will be able to access this repository. Then there's another problem, like now if I added everyone's public key in this repository, so everyone can access this and the problem which we're facing with the local, keeping a local repository, local protocol that anyone can go inside and delete that dot means the files. They can corrupt the files. So probably we wanted something. So I added those keys, but he should be able to do only jit or clone or push or pull, but not able to directly as such log into it. So jit comes with jit shell. So you can keep your default shell to a particular user to jit shell. So it will only allow you to clone or push, pull to that repository. You won't be able to as such to it. So there will be like a only particular user who will be having access to that machine. Not everyone will go and can change the content there. So that's it for the part where we actually have set up a jit server. We're able to clone and push and pull our changes. Then comes we need something because jit-wap means jit hub has a nice UI also. So we need something, some basic to it. So we can always do a jit-wap setup which is already there for provided by the jit. So I have some commands ready for me. So I'll be installing the Apache here. So if you go check, so currently there's nothing. So we'll install Apache. So we have set up the Apache here. So we need to clone this jit repository. So which is having this jit-wap. We need to install make also because for the further step we need to... So if here we can see this jit-wap project root. So that's the path which you have to give where all of your repositories are present. So because our repository are inside at the home. So that's why it's home open to here a jit-wap project root. So now we have this jit-wap ready. So we can move it to access by Apache. So there will be a CGI script. So we need to enable running CGI scripts. So that's this commands for that. And you need to restart after doing that. And plus we'll add a virtual host for it. So if you do, there's this default file. You can sudo vi. So there's already one virtual host present. We can doubt for a while. So here we are opening 80 port, which will be pointing to where www.jit-wap where we just copied the files. And we need to execute CGI scripts. That's why we have to give the options, execute CGI. And we are adding the handler here, CGI scripts to run it. And where's the index? It's jit-wap.cgi. So if you go inside this one, which we just copied. So there are this jit-wap.perl and jit-wap.cgi file, which we are going to execute. So now we have actually added a virtual host and we have enabled the CGI script. So we need to restart apache. Let's go and see. Wow. Let's go. Yes, point it to 80, right? Will there be issue in tabs and spaces? No, right? Jit-wap, correct? Yep. Here? Yeah, here. That's inside there. Failed compilation border jit-wap. It should be fine. Anyway, I... So there's one... I've published this on Medium. This one is on EC2 instance. And... So it will look like something like this when you have this running. So here our basic things are here. Like you can search based on Shah. You can list all your projects here.  So it's a basic UI which you probably will be needing for jit. There's no CI or anything like fancy stuff, but yeah, basic UI for it. So that's it. Yeah. I think jit-wap is only for read-only. You won't be able to create a new repository. So with jit-shell... Jit-shell or just a normal shell you are talking about? Jit-shell. Yeah. Probably, I'm not sure. From normal shell, definitely you can create. But you don't want your... Oh, that way you are saying... Yeah, probably you will be able to create. In jit-shell? Yeah. Probably should be. Because now it's actually more dependent on your server which you are using, server capability, because everything is yours, local, and plus how what... So I used micro based on servers and all performance. That's the thing I think. So basically jit-lap will be a better option if you are trying to host, because it comes with a huge community and a lot of other fancy tools also. This is something which I gave presentation because if you know basic how you actually... how the server is working, how you are actually communicating the server, what all protocols are there, what are repositories, kind of repositories, bear and non-bear, what's the difference between that. So it's easier to play with a toy which you know what the toy is and how it works. So that was the main objective of having this presentation. So any other question? Thank you.


I think it's so interesting that in ancient Egypt and certainly in South Asia as well, the architect was privy to secret knowledge, again knowledge that would be used in constructing a temple, constructing a palace, again building typologies really associated with the upper echelons of society and power. And so architects were also thought particularly in Egypt to possess magical powers and I think in today's architectural profession they still cultivate that as well with the star architect. I mean I was just reading although he would probably dispute this you know identification with the star architect, the Swiss architect Peter Zemtor and the notion that he has to interview the client and the client has to convince him that he or she is worthy of having a Peter Zemtor architect. So again instead of being initiated into the cult or the priestly caste of architecture in some way and so in a funny kind of way I think that mixing up of architects with magic and religion and again having certain powers still continues on today. Certainly in this country the architectural profession has always been very market driven in the absence of sustained patronage by the state and the government at whatever level in this country has always been a fairly reluctant patron of the arts and architecture and again the concern you know as to whether or not public monies which were limited and particularly are limited today are put to the best use by going to art and architecture. So architects in this country have always had to be entrepreneurs and they've always had to market themselves and in a funny kind of way I think that in our media saturated culture and a culture of branding and of self promotion in many ways American architects historically have been the best equipped to deal with that because they didn't have the cushion of either private patronage or the state as a patron as they did in Europe and certainly globally and so architects in this country have always had to scramble and part of the problem again was that they were so far outnumbered by master craftsman and master builders so they've always had to make an argument for themselves in terms of the greater fees that they charge the greater time that an architect invests in a project typically and the fact that it wasn't one stop shopping that you not only had to pay an architect but then you had to pay a master builder or a general contractor so architecture really didn't seem to many clients and consumers to be an economically advisable form of designing and constructing buildings. Rourkeism is a term that I have used in my writing on the architectural profession and I think others have used as well and it obviously comes from Ann Rand's protagonist Howard Rourke in a novel that is often invoked and evoked but I wonder if it's actually read I have to confess that I found it difficult to get through a very dense novel but one that again the protagonist is Howard Rourke and many modern architects like to claim that they were the model for Howard Rourke because of his sexual prowess as well so Frank Lloyd Wright said of course I'm the model for Howard Rourke or Richard Neutra claim that he was the inspiration for Howard Rourke but he represents in that novel and the 1949 film in which Gary Cooper portrayed Howard Rourke the idea of the architect as an uncompromising individualist and very much a loner an outsider as well I mean you never see Howard Rourke interacting except with potential clients those who are going to bring his vision into reality so architecture is always seen as a kind of singular practice and that the sum of the architectural process is very much encompassed by again the design expressed through drawing or through the model the inspiration that's given some kind of tangible form and then the architect is a very charismatic and prophetic figure who has to convince often recalcitrant clueless clients to buy into his vision and again this notion of the architect as embodying a very masculine expression of power in some way that the woman can only be the sort of helpmate or the architectural critic to advance the vision of a Howard Rourke so I've referred to now it's commonly known as star architects is tracing their lineage back to someone like Howard Rourke although certainly during the Renaissance period in the notion of the architect emerging now as an artist someone who's not tied necessarily to the traditional building crafts and trades and tied to the construction side it has a very very long history I think it's interesting that if one begins to understand what is modern about the practice of architecture and this discourse in the late 19th century and continuing into the early 20th century that to be modern was not only a formal quality but it was the way in which one organized one's practice as well and architects began to emulate large businesses and industry there the practices became very specialized there no one architect could encompass the kind of technical knowledge as well as the artistic knowledge and the business acumen that were necessary so you have the development of partnerships oftentimes of two and three partners and then you had what I like to see is sort of the the base of the iceberg in a way you had these huge numbers of draftsmen who clearly we're never going to become independent practitioners we're never going to become partners in the firm and so they could only participate in terms of these firms if there was a sense that they were included in a practice that was dedicated to art there was also the notion that monumental buildings served a social good particularly in this country which I think is a somewhat specious argument that it was a grand and monumental architecture based upon the classicism of the Mediterranean world that somehow was going to knit us together and the public spaces that it generated and of course the people who felt comfortable in those public spaces were again a very small slice or who were welcomed into those public spaces were a very small slice of our diverse population in terms of race in terms of ethnic group in terms of socioeconomic class I think that architects have always made a kind of Faustian bargain in a sense that they are dependent upon patrons and it's going to be interesting to see given the uprisings in the Middle East now so many western architects have practiced and have had incredible commissions for museums for entire college campuses and we're seeing the kind of fallout in terms of politics of one is too closely identified with these dictatorial regimes for our own geo geopolitical interest and I think architects for their own architectural and artistic interests and I was very interested to see that some of the artists whose works might be included in the Guggenheim in the Middle East were saying they didn't want their work shown unless there was a commitment to improving the living in the working conditions of all of the immigrant laborers who were brought into Dubai who were brought into these countries really under horrific conditions I think again that kind of moral strain that we talked about that infused architecture in the United States from the mid 19th century forward and so influenced the modern avant-garde movement with a social idealism but again they were dependent upon government and workers unions to provide the funds for public housing and workers housing at that time and unfortunately in this country in the neoliberal state as we've seen in the recent attacks on unions those kinds of sources and the idea that government should have a very limited role that kind of patronage really seems to have disappeared particularly in this country so I think it's it's very difficult for architects and I see it in my students who who want to do good who do have a social conscience and although their numbers are still relatively small in terms of schools of architecture I mean that's a really horrifying statistic that African-American architects in the 1960s I think constituted one percent of the architectural profession and today I think it's only something like 1.5 or 1.7 Hispanics are better represented 8.6 and now women are almost 25 percent of the architectural profession so we really have an advanced and in part I think it's because of where the commissions come from it's still a white male power structure that has it within their purview to award commissions