The Inevitability of Physical Laws: Why the Higgs Has to Exist | Nima Arkani-Hamed

good evening ladies and gentlemen I'm Robert I craft the director and Leon levy professor at the Institute for Advanced Study and it's a great pleasure to welcome you at this kind of sold-out event a perfect talk that coincides with our semi-annual Board of Trustees meeting it's a particular pleasure to welcome our trustees to this event just as a practical matter we will have a lecture then at the end of it will be in a question and answer period now our speaker today requires little introduction its Nieman Americana Hamed who will is a professor of course in the school of Natural Sciences at our Institute and the title you already see behind me the inevitability of physical laws with a subtitle why the Higgs has to exist now Nemo is particularly firm on this because he kind of very publicly announced that he was willing to bet a year's salary if the Higgs boson would not be found and one of the most pleasurable experience of my just the first few days of my tenure here was that on the very early morning of July the 4th we had a very special fireworks because we had a champagne toast to the discovery of the Higgs particle and actually that champagne was at a cost of somebody had taken up that bad and so happy to report it was a high-quality champagne that we drank nema is somebody who kind of expresses is kind of wonder and enthusiasm about physics in a quite unique and powerful way although both his parents was physicists he described themselves to be as an act of teenaged rebellion to study physics anyhow and so I think actually this is a very clever act of reverse psychology on the behalf of your parents thank you very much you studied at University of Toronto and earns you PhD in physics from the University California in Berkeley in 1997 NEMA worked as a postdoctoral fellow at the slack National Laboratories before becoming assistant and an associate professor at Berkeley in 2002 he moved to Harvard to become a full professor there and remained there until he joins our faculty of the Institute in 2008 there is an endless list of honors that Nemo was awarded I just mentioned the Sloan fellowship Packard the group of medal of the European Physical Society and the Raymond and Beverly sector prize but I think in many ways this was kind of talked by price that was rewarded at the end of July when we in that month we had another piece of excellent news which is NEMA along with three colleagues here at the school of Natural Sciences was among the first winners of the fundamental physics prize and that's a remarkable recognition of groundbreaking contributions to theoretical physics and excluded a very generous award of three million dollars to each of the laureates and you might kind of wonder whether NEMA you would still have bet your year's income if you would have no death head purpose in fact we are especially delighted that the creator of that price dr. Yuri Milner is here to kind of celebrate that so warm welcome to you Nima's work on particle physics and its connections to experiments is truly visionary there's a long list of his achievements but all of them I think stand out in terms of very fresh and broad way of thinking very unexpected way of thinking and that has enormous traction both in the theoretical and in the experimental world and he for instance his radical ideas that could be very large in terms of physics speak extra dimensions completely revolutionized parts of theoretical physics and he has also played a leading role in how these modern theories what the implications are for the great and exciting experiments that are going on now at the Large Hadron Collider in Geneva after the announcement was made of the discovery of the Higgs this summer the new york times quoted NEMA as saying it's a triumphant day for fundamental physics now some fun begins and I think that fun is a not can't think of better hands to put that fun than in Nima's and I hope that you will join me in welcoming here to the stage Lima well it's a really tremendous pleasure to be giving this talk today as you all know the Higgs was discovered politically correctly speaking a Higgs like particle was discovered at CERN back on July 4th and there's been an endless slew of descriptions of what the Higgs is and and what the Associated ideas are in the popular press and they all use one variety of metaphor or another to describe the physics now there's a problem with talking about the Higgs that almost all these metaphors are just terrible and they don't actually reflect what's really going on but all of us I've used these metaphors myself so I'm not besmirching anyone else but but for the purposes of this talk I decided I'll try to do something very dangerous which is to try to explain what's actually going on and I take some inspiration from the spectacular talk one maldacena gave here number of weeks ago that that I hope many of you were also at once talk was really precisely correct to used analogies but the analogies were not just random analogies they were really precisely in a very sharp sense correct and I'm using that as an inspiration here as well are the talks are going to be completely complimentary and in a few places I will talk about what the sort of connections are between these two ways about thinking about things one aspect of the story that I really want to highlight and emphasize and it's it's a broader point that than just the Higgs we're going to use the Higgs as an illustration of this general point is often when we talk about what we what's going on in in physics I think if you're not a professional physicist you might get the sense that these are a group of people who are just pulling things out of thin air a left right and center and somehow they describe nature sometimes maybe other times they don't and you know whether they work or not work is dependent somehow on their sense of aesthetics what's pretty what's good what's bad but but it seems perhaps very dependent on on on the people who are thinking of these ideas and what's not I think commonly appreciated which is what I really want to stress in this talk is we understand so much about the way the world works that a lot of the broad outlines of what even possible candidate theories that could describe nature uh can look like are just forced on us there's nothing we can do about them there's no choices there's no you know ten thousand other way things could go and we're choosing some of them because we like them because they're pretty the way the world works is all what is very very largely constrained by the laws that we know already there is an inevitability about the structure of the laws of nature which is what I want to talk about and a particular example of this kind of inevitability this incredible power we have in our understanding of how things work is is going to lead us to why it was that so many of us certainly not just me many many people have been would have been willing to bet years of salary that the Higgs had to exist but why it is we knew I mean if you think about this kind of amazing there's this group of people a few theoretical physicists wandering around the world who and you when this experiment is done this this big experiment is done this particular measurements are made this thing must happen we just knew that ahead of time and it happened so why are we so so confident why are we so sure it had to happen that way that's what I want to convey in this talk so let's start just with a review of what we know about the world so the most basic sense we know there are things out there made out of matter matters made out of atoms and in atoms we have so here's the hydrogen atom we have an electron going around a proton and if we take a peek inside the proton we now understand that the proton is not actually a fundamental point like particle it's in self made out of other particles called quarks so the proton is made of two up quarks and a down quark a neutron another constituent to the nucleus emitted of two down quarks and an up quark and this matter is acted on by various kinds of interactions we know there's four basic interactions two of them that people new for new about four for a very very long time gravity and electromagnetism and to that we discovered really at the very very end of the 1800s in the early 1900s which operated very short distances the strong nuclear force so inside the nucleus for example we can have two protons and two two neutrons here this isn't he Liam nucleus and you might wonder why these protons manage to stay inside the nucleus they want to repel each other by their electric repulsion well early on there was something that people imaginably called the strong force that kept them inside the nucleus we now understand that this strong force is the residual of something else that we'll talk about a little more and finally there's something called the weak force or the weak interaction which is ultimately responsible for radioactivity if you take a neutron out an empty space it sits there for 15 minutes and then it disintegrates it disintegrates into a proton and electron in something called an anti-electron neutrino now 15 minutes are gargantuan time scale compared to all the times all the various times in atomic physics and nuclear physics and so on so that's why it was called the weak interaction that to be something incredibly feeble that that had to take so long in order to do in order to do this but this is ultimately what's responsible for radioactivity and these interactions acting on the matter that we know and other particles that we've discovered since hold sway over an enormous range of distances all the way from the size of the observable universe around 10 to the 28 centimeters big down to as we go down to shorter and shorter distances or something exciting happening at almost every factor of 10 shorter and shorter distances galaxies are a million times smaller in the universe the distance between the earth and the Sun is like 10 to the 13 centimetres a people are like a meter big atoms protons and neutrons are around 10 to the minus 14 centimeters incredibly tiny around a million times smaller than the atom itself and finally we go down to this very very short distance scale we'll talk about a lot in the rest of the talk around 10 to the minus 17 centimeters it's called the week scale that happens to also be around the frontier of what we're probing with very very high energy accelerators like the Large Hadron Collider were actually probing these very very tiny distances now a remarkable thing that we've discovered is that actually all of these things this whole collection of stuff the matter and the interactions are described in a completely common way and a completely common language so if we start with the most familiar if we start with the most familiar interactions just the electromagnetism would be electric repulsion between a pair of electrons and and gravitation it turns out that all of these both of these interactions are associated with a little stick figure like this electrons interact with a photon here they can interact with a graviton the thing which interacts with the photon is actually the charge of the electron the thing that interacts with the graviton is well in in the Newtonian picture of the world the force of gravity has to do with masses the more and more mass of an object is the bigger and bigger gravitational force you have but we now know because of relativity equals MC squared so really the thing which is the thing which is the analog of charge for gravities the energy or the momentum of the of the apart achill so there's a charge associated with here which is like the charge which is the normal electric charge and the analog of the charge when it interacts with gravity is energy and momentum so there's some basic little stick figure interaction like this and everything else which actually happens when we take electrons and photons and make them interact just comes from putting these pictures together so if I want to have two electrons banging into each other what's really going on is two of these basic two of these basic building blocks and exchanging a photon there between them so in a specific sense that that I can't serve these pictures but which but which is really there if they're precisely there are some sense in which there's not a real photon but what's called the virtual Photon something that's sort of quantum mechanically to a ting out of the vacuum which is what's giving rise to this force between two electrons and you can see the force between two electrons gets weaker and weaker as you go to larger and larger distances that tells you something it tells you that that the size of these quantum mechanical fluctuations is weaker and weaker at larger and larger distances it's stronger and strong stronger at shorter and shorter distances and that's that's a sort of a basic consequence of the Heisenberg uncertainty principle but anyway that's the that's the that's a picture we now have for the simple fact that the two electrons can for example scatter against each other just by repelling each other by their charges and you can put these together to make all sorts of complicated processes you know so all sorts of complicated things happening in the world in the end just come from gluing together these basic little elementary interactions now the strong and the weak forces don't look like that at all on the face of it they look completely different than the electromagnetic force and the gravitational force but the amazing thing that we learned in the second half of the 20th century is that in fact all of these forces are described fundamentally in exactly the same way that if you go to short distances you discover that what's really giving rise to the strong force is exactly the same kind of stick figure instead of having electrons interacting with photons we have quarks interacting with something called gluons okay so this is what's responsible for the strong force the the weak interactions are associated with instead of having two electrons interact with a photon we can have an electron and a neutrino interact with something called the W boson it's just like the photon all the pictures look exactly the same they're a little detail there's some few detail differences here for example so far in all the pictures it was the same kind of thing quark quark quark quark electron electron here we get something a little new we have an electron and a neutrino but it's not really fundamentally different for the quarks so these are the weak interactions now we can have an up and a down interacting with this thing called the W boson and they it turns they have a cousin called the Z boson that that does just connect for example an electron electron and a Z so fundamentally at short distances they look identical essentially identical so why did we think they looked so different why did we why do we know about gravity and electromagnetism for centuries and centuries and only found out about these other guys like 100 years ago 110 years ago and the reason is that the apparent enormous disparity between these forces is a kind of a long distance illusion for example let's let's talk about the strong interactions so we have the the quarks interacting with these gluons now we have electrons and photons we've seen electrons and photons out there in everyday life how come we haven't seen the quarks and the gluons out there in everyday life it turns out to be a detailed effect it's a very important detailed effect it's a detailed effect that earned some people the Nobel Prizes uh back in the 2000 but it's really a detailed effect that that that because of some subtle quantum mechanical reasons the force between the interaction strength between quarks and gluons gradually gets stronger as you go to longer and longer distances very very gradually gets get stronger and eventually at a long enough distance scale it becomes so big that it traps the quarks and the gluons and everything else in taut inside the protons and the neutrons so we say that they're confined this is at a very long distance scale a long distance scale to a particle physicist is around 10 to the minus 14 centimeters a million times smaller than the atom okay but this is to us as a gargantuan very very big distance scale okay but this this is the detail it's a very important detail but but it's a detail fundamentally it's the same thing fundamentally we have these same basic stick figure interactions what about the weak interactions well the reason why I took so long to discover the weak interactions the reason they're so weak is is even simpler the photon is a massless particle because it's a massless particle it doesn't cost it doesn't it doesn't cost as we go to longer and longer distances it's sort of possible to get longer and longer wavelength excitations of the photon that have lower and lower energy and so no matter how long distances you go to you get some force from it some reasonable size size force from it granted it gets weaker as we go to long distances but it's still visible and we talk about it's a famous inverse square law the difference is just that the W particle is massive it's not massless its massive and because it's massive it really costs an enormous amount to excite it out of the vacuum so the range of this weak interaction is very short-range the the the W boson is so massive that the effective range of this interaction is something like 10 to the minus 16 centimeters or so which is a hundred times smaller even than the atomic nucleus but again it's a detail if we go too short enough distances everything starts looking similar this is the real reason we want to build high energy accelerators and go to short distances in our part of physics it's not so much because often when people talk about this they they they talk about wanting to understand what the building blocks of all matter are and things like that maybe that's what some people care about it's not so much what I care about I think it's not a lot what many of my colleagues I care about after all understanding you know all the different building blocks of matter sounds something like chemistry and I kind of flunked chemistry a number of times so I so uh so it wouldn't thrill me to be doing something like like chemistry no that's not what well we actually do it we go to short distances because we've learned in this way we've learned that the essential unity simplicity of the laws of nature become manifest they're hidden at large distances by a variety of accidents but when we go to short distances we finally see them this is a really extraordinary fact that we see for the first time all these different interactions described in a common way a common language is one set of stick figures describing everything it's pretty amazing and we discovered that by going to short distances so it pays to go to short distances because then you see what's really going on with the fundamental laws of nature unvarnished unknown not hidden by these accidents you know took us 2,000 years to go to distances short enough to see that all this was true but then we see it's true we've learned something really profound about the way the world works okay so now for a lot of the rest of the talk maybe I should have said this at the start this is not the most conventional description of the Higgs and in all of this the physics and it might require a little bit more audience engagement so we're going to be we're going to be thinking and counting on our fingers a lot okay so but but we're going to have to count a lot you know actually one hand will probably suffice let me think about yeah one hand will suffice it but but you're going to see these numbers floating around 1/2 1 3 halves to 0 and so on so just just just be forewarned that we're gonna see a bunch of numbers floating around ok all right now there's a really important property that particles have it's actually one of their defining properties it's one of the things that labels what a particle is the particles have something called a spin so you can think of an electron very loosely as like you know has some charge and it's spinning around it intrinsically has some spin it can spin in some some direction now so there's some angular momentum that's associated with that spin but this is really an intrinsically quantum mechanical thing and the amount of an angular momentum that it has it turns out that Planck's constant H bar this is Planck's constant of quantum mechanics H bars units of angular momentum so we can actually measure this angular momentum in units of H bar and it turns out that all these angular momenta come in multiples of 1/2 so so we can have no idea of momentum zero we can have angular momentum 1/2 times H bar we can imagine aluminum 2 times 1/2 times H bar so 1 times H bar or 3 times 1/2 times H bar 3 halves H bar and so on that's the list of allowed spins we can have zero one half three oh this all this stuff and the particles that we know and love okay they have relatively simple spin so the electron has spin 1/2 the photon is it's moving along as spin 1 the graviton turns out to have spin 2 these W boson and the gluon and the Z boson also have spin 1 okay so we have relatively simple numbers floating around here okay okay so the particles you see are really extremely simple in fact it's just the fundamental particles that we see just have spin 1/2 1 & 2 nothing else so here we are the electron can interact with the photon I don't know why I put a W there that's 1/2 1/2 and 1 the electron can interact with the graviton 1/2 1/2 2/3 gluons can interact they all have spin 1 and so on okay but so now we see two kinds of simplicity first the basic interactions are just these little stick figures and secondly the spins that are involved are incredibly simple just just 1/2 1 & 2 and you don't have to look at this in detail but in fact we know about more particles in the familiar ones but the whole menu of everything that we know of in this thing called the standard model of particle physics it's just exactly the same it's just it's a bunch of particles of spin 1/2 of spin 1 and 1 particle of spin 2 which is the graviton there's something special about gravity gravity is completely universal it interacts the same with everything so there's one particle to spin to graviton everyone else is just a collection of things that are spin in half and spin one now there's a big collection of them there are particles that some of them some of which you've heard of like maybe electrons or the quartz that we talked about they're more exotic ones like for example the top quark is the heaviest of all the quarks it was discovered in in the mid 1990s it'll play a role in the later in our story okay so now that's something that we know describes nature but now I want to ask another question why is it so simple now part of it doesn't look all that simple the actual menu looks a little bit complicated we have all these different kinds of particles and they have different names and stuff like that but the basic structure is incredibly simple why these little stick figures and why do we only have these simple things spin 1/2 spin 1 spin - why don't we have more complicated things it could have been much more complicated ok so here are two questions you can ask why are the simple fundamental interactions look like ABC only 3 guys why don't we have a fundamental action that like interacts 12 guys together okay that would be terrible right because then we'd have to glue these together and like the 100 ways and it would be a horrible mess but we don't get that all we get is this why is that first of all and secondly why is it that we have such a cleaning menu of spins that we can talk about why do we only see 1/2 1 & 2 okay now this is an example of what I was referring to earlier as inevitability this is something truly remarkable that we've learned in the that that's I mean we've known for a long time it's a sort of a bedrock it's a very important piece of our current understanding of the reality and it's the following slogan we don't understand everything about physics by far definitely we don't okay but what we understand so far is powerful enough to tell us the following whatever the heck of the ultimate theory is just the laws of relativity and quantum mechanics together we need both of them both relativity and quantum mechanics guarantee the following amazing fact that at long enough distances it'll be clear what I mean a little later but long enough means anything that we care about that that we could interact with and know of and so on and long enough distances first of all the only things that are going to matter the only things we could possibly detect that will matter for the interactions are these basic little stick figure interactions ABC ok so we don't get these horrendously complicated things a and B now I'm telling you this is a consequence of relativity and quantum mechanics what I mean is the laws of relativity and quantum mechanics are very general principles we have our specific universe of course we care a lot about our specific universe okay but these laws of relativity and quantum mechanics are very general principles and so as theorists we could imagine what all possible consistent worlds could look like that we're consistent with those laws of relativity in quantum mechanics so let's do that exercise ok let's take what we know relativity and quantum mechanics imagine what all possible consistent worlds could look like and the answer is all possible consistent worlds at long enoug distances again they have to have these basic interactions and the only means that can possibly make sense or the following zero one half one three-halves into now notice that so far we've seen one half one and two we haven't seen zero and we haven't seen three-halves but it's not in contradiction with this certainly oh and by the way that's been two guys totally unique in its gravity it's the thing that's associated with the gravity in other words this this this this the this understanding tells us that this guy is totally unique there could be a whole bunch of these guys it could be a whole bunch of these guys there could be a ton of these guys in principle this guy is very special we'll come back to that as well you can have at most eight of those guys it turns out but anyway we'll come back to that a little bit later okay so this is the claim and now I want to explain to you where this claim comes from actually before getting there this is a good spot to just echo the sort of title of my talk this fact is an example of what I mean by inevitability you don't know it ahead of time we have these general principles of relativity and quantum mechanics and they have as a very surprising outcome this fact that inevitably no matter what things have to be described in this particular way with this particular tiny menu of particles interacting in this very specific way another set of words associated with this are rigidity the laws of physics are incredibly rigid you can't mess with them you get what you get after some basic principles you don't have choices so it's not like we're sitting around and I like leprechauns and you like fairies and we invent different stories what we know already is incredibly rigid now there's a fascinating flipside of the rigidity which is that they're also very fragile okay what do I mean by fragile it means that if you now try to monkey with the basic principles you will make it break immediately if you say you know what I don't like relativity let me just let me throw out relativity a little bit you'll completely smash this inevitable everything comes out in this unique fantastic way okay so so these are two remarkable flip sides laws are very rigid very fragile at the same time they're very rigid within the structure we have and they're very fragile to monkeying with the structure and finally these things often in physics and in mathematics as well people will talk about beauty ideas are beautiful and nice and so on what we mean by beauty is this actually it's not it's it's a very specific notion of beauty things that are beautiful ideas that are beautiful theoretical structures that are beautiful have this feeling of inevitability and this flipside of rigidity and fragility about them now this is something that I could go on and on about for a long time but I shouldn't do it because probably to my mind the greatest popular physics book of all time is this book by Steven Weinberg dreams of the final theory if you haven't read it I very very strongly urge you to read it and this whole theme of inevitability and rigidity and fragility and so on is beautifully discussed there amongst a number of other things okay anyway that's the claim so now I want to now I want to give you an idea for why the claim is true right so so we are going to now do a couple of things I first want to tell you why it is that no matter what's going on fundamentally at long distances we can't have the basic interactions that we can have only have to have this ABC variety first and then after we do that I'll tell you why they only have to involve these very special pattern of spins okay and I'm going to try to do everything as honestly as possible but there's a couple of spots where you'll just have to believe me okay now actually our foray into the subject is going to start with something that's incredibly prosaic credibly prosaic we're going to talk about units and it sounds like the most boring subjects in the world but it's actually not boring there's something extremely important about about about units normally we have all kinds of units and meters jewels all sorts of different units and it's really hard to keep track and remember what they are certainly at least when it when I was in high school this was the bane of my physics education existence was remembering what all the units were now you converted between them and and there's actually a good reason why it's so confusing because the normal way we talk about units is a completely human artificial construct when we talk about distances when we say like you know so-and-so basketball player is two meters tall okay what do we really mean what we really mean is that some people in Paris long time ago put a bar somewhere okay a bar of metal and this barbed metal they called one meter so what we really mean is if we were to go take that bar out of Paris and lay it next to this guy twice we've got the same thing right so everything is actually you know that there are no units really it's all it's always two things relative to each other right so we're when we say something is 2 meters we're comparing things with this bar in Paris we say it's kilograms or whatever it's some other weight in Paris or I don't know what are these things are in Paris but anyway ok but that's that's not very reasonable that's completely artificial human construct so there's something else that we can do which are called natural unit there as it sounds they have to do with nature rather than to do with human beings and also there's something else that's very important our world has both relativity and quantum mechanics so there's a speed of light which is an important constant and Planck's constant to quantum mechanics which is an important constant and these constants let us actually switch between for examples here's a familiar one time and distance we can actually measure with the same unit I can say that the distance from here to there is 3 times 10 to the 8 meters or I can say it's one light-second and it's exactly the same it's the distance that light travels in one second so that's what lets me trade back and forth between between between time and distance similarly energies and times that can be related through Planck's constant and energy times a time is has the same units as Planck's constant so what we say is that we work in units with these constants R 1 H bar and CR Planck's constant and the speed of light are set to 1 and what that really means is that we can determine all the units that we know and love in terms of 1 basic unit we can make that unit anything we want we can make it energy we can make it time we can make it mass we can make a distance yep and starting from one we can get to all the other ones so let me give you an example so uh in in particle physics we tend to use this unit that's one Giga electron volt so it's a unit of energy but actually the very interesting fact about it is that that energy is almost the same as the MC squared energy of a proton so it says this was around point nine three eight GeV but let's just call it one okay so the mass of the proton is around 1 GeV okay so whenever you see 1 GeV just think of it as the mass of the proton now in these units I can then translate everything into one unit for example GeV for instance so here's me so my height is around 10 to the 16th inverse GeV okay 1 over G V is units of length okay so you see 1 over an energy has units of time times units of distance so I'm around 10 to the 16th inverse GeV now this is incredibly useful way of talking about my height let's say you're going to talk to someone in Alpha Centauri and tell them how tall am I it would do them no good to say if you go to Paris and put me up next to this bar right that would that would be no no good but you see this the size of the proton 10 to the minus 14 centimeters is around one of its inverse masses one of our GeV so when you say I'm 10 to the 16th inverse GV hi you say if you put 10 to the 16th protons end-to-end you get me that's very useful information they know immediately is the protons there are the same as the protons here my mass is around ten to the twenty-nine GeV okay that's that's really useful too because it tells you how many protons are made up immediately and that's most of my mass is that that's others around ten to twenty nine protons in me if you're very lucky and the lecture time will be around 10 to the 27th in RIT's GeV okay the LHC energies the beam the energies of the protons in the LHC are 7000 GeV okay so these are the sort of natural units that we use now when when we work with these units we discover something remarkable right away so let's let's let's look at something that's very familiar let's say we look at the force between two electrons so you remember from from high school probably the force between two electrons is a charge a charge and it goes like one over the square of the distance between them okay but if you just use the rules I told you it's very easy to see that force actually has units of 1 over length squared so that means that this this charge times charge is charge squared is just a number see the units of force are the same as units of 1 over R squared so this charge squared is a number turns out the numbers around 1 over 137 it's just a pure number that's extremely interesting the the electric force is associated with the pure small numbers around 1 over 137 by contrast if we look at the gravitational attraction between two electrons you'll also remember from school that it's the Newton constant times the mass of this electron times the mass of that electron over R squared and so that tells you that that that Newton's constant in these natural units has the units of length squared so G Newton in these units is around 10 to the minus 33 centimeters squared and that length was called the this this famous Planck length this is Planck length squared okay so this is a minuscule number compared to everything that we know in nature and the fact that it's minuscule is reflecting how weak gravity is compared to all the other forces it's a direct reflection of that fact but you notice that it's not a pure number it has unit and that means that it's not actually true than in some sense the gravitational force is weak you see in some very meaningful sense the the electric force between two electrons is weak the actual strength of the interaction is a small number but here it's not a smaller a big number if your distances that are large compared to 10 to the minus 33 centimeters it's very weak but if you start approaching 10 to the minus 33 centimeters it starts getting strong so there's no there's no meaningful sense in which whether it's weak or strong depends on whether your long or at short distances now there's there's a there is another interpretation of what these numbers mean which is which is very important which has to do with quantum mechanics in quantum mechanics something you know is that we can't actually predict what happens next when we do one experiment okay if I take two electrons and I fire them at each other then the electrons can come back out at some angle so they fire them in here they can come out at 30 degrees the first time I do it I do it a second time exactly the same conditions it might come out at 90 degrees might come out at 70 degrees okay so we can't predict what happens next the crucial feature of the quantum mechanical universe instead what we can predict or what are called problem or probabilities and there's a peculiar rule in quantum mechanics that tells you to get the probabilities you actually have to calculate something else called an amplitude and square that number nevermind what this means exactly but but so the probabilities and amplitudes are basically the same thing we have to square the amplitude to get the probability now what do these small numbers that we talked about what are the numbers that we talked about before mean in this context means if I take two electrons and I scatter them together again I don't know what happens next but there's some probability that they might come out at 40 degrees 50 degrees okay there's some probably that nothing will happen at all those just pass through each other the overall chance that anything happens they actually scatter let's say it more than 40 degrees that amplitude is set exactly by the small numbers this charge squared it's around a percent okay now that's a much more specific sense in which these numbers are telling you something about the tiniest of these interactions if you fire electrons at each other most of the time they don't do anything some fraction of the time around 1% of the time they'll scatter at some angle of course we can't predict which angle but we can predict the probabilities that comes out at various angles but all those probabilities have this whomping 1% all squared sitting in front of them so it's a small probability for this to happen now gravity is completely different and this is a sort of central mystery of gravity if we do exactly the same thing for gravity we find that again precisely because G Newton as units that this amplitude instead of just being a number like 1% is G Newton times the energy squared so this number this this probability is like so ridiculously tiny at at the normal energies that we talk about it's a truly minuscule minuscule minuscule number and at energies that are less than 10 to the 19 GeV gargantuan enormous energy scale this is minuscule but on the other hand it grows as we go to higher and higher energies that in quantum mechanics corresponds to shorter and shorter distances we find eventually that this amplitude starts becoming around 1 or even if I continue this formula bigger than 1 when I go to begin urges now amplitudes bigger than 1 are nonsense because we have to take them and square them to get a probability probabilities all have to add up to 1 we can't have probabilities that are bigger than 1 so this is just telling us this very simple argument about units tells us something very strange and bad is happening with quantum mechanics and gravity when the energy start approaching these gargantuan energies of order of the Planck energy or as we start getting to these tiny distances of the Planck length ok now this argument about units now tells us something quite amazing pretty pretty quickly so if we go back to the stick figures that we knew before the interaction between electrons and photons I told you that strength of the interaction is around 1 over 137 remember I told you that the other all the other forces have basically the same stick figures remarkably the strength of the interactions are also relatively similar they're not exactly the same but for example the typical the strength of this charge for the strong interaction is like a tenth ok it's stronger than that one but it's still a relatively small number for the weak interaction just like a 50th ok so we have all these numbers but pure numbers around 1% 1/10 and so on ok all right but why then couldn't we imagine that we have these much much more complicated interactions the reason s the reason is the following let's say we had we had an interaction that that had that had one more guy coming out or two more guys or three more guys this is a quantum mechanical process that's producing them and so we need to have some some quantum mechanical fluctuation out of the vacuum to produce these particles but we've seen already just from the weakness of the force between particles remember I told you as the inverse square law the fact that the force gets weaker as we go to longer and longer distances is telling you that it's harder and harder to get a quantum fluctuation at larger and larger distances conversely it's easier and easier to get a quantum fluctuation at shorter and shorter distances but that means that as you go to long distances it pays for every extra particle that you emit you have to have some other factor it's harder and harder to to a do it and that means that all of these guys only these stick figures can have coefficients that are numbers pure numbers like this all the other ones just like gravity have some length in front of them have some light scale in front of them and that means no matter what the heck of the underlying theory of everything is we don't even know what it is okay but there's something maybe up there near the Planck length where fundamentally we need to have a much deeper understanding of what's going on with quantum mechanics and gravity and so on whatever there is up there or beyond there at large enough distances even if there are such interactions we won't notice them they won't be relevant for describing what we see they'll be tiny the only things that will survive the only things that we will detect and notice and we can use to build our interactions are these basic stick figures so this is an immediate consequence of thinking about units correctly it's an incredibly deep fact about nature that tells us whatever the heck the ultimate theory is that long distances it's guaranteed to be described by only these basic stick figure 3-point stick figure interactions all right so the next thing I have to explain to you is why it is that the menu of spins that we have is so restricted why do we only get this tiny tiny set of things that we can have now I'm going to since since since as we've discussed a number of times the all the real the basic fundamental structure of how these particles interact makes sense at very high energies we're going to do an approximate that makes our life very very simple and coming back and think about the approximation carefully and a little bit is going to be the entire story of the Higgs so so keep that in mind but but let's first make the simple approximation that if we're imagining we're banging things into each other incredibly high energies clearly we can ignore the masses of the particles whatever the masses of the particles are they cannot possibly matter if we're banging them into into each other at energies that are much much much bigger than the MC squared energies that the particles have so we're going to do something sort of bold and immediately think just in terms of massless particles so we want to see what kind of interactions can we have just for massless particles now there's something very interesting about the spin of massless particles ok we'll come back to this again later but remember we said that the spin is like the electron is like a top so can spin this way it can spin that way it can spin that way and spin in three different directions but this is a little different if these particles are moving at the speed of light because they're massless and I'm the moving of the speed of light then well so let me actually back up how do I know that that an electron can spin this way and that way and and and that way it's very simple no matter how an electron is moving let's say it's whizzing along this way I can always run and catch up with it so there I'm catching up with it right let's say it's spinning this way if I turn my head it'll look like it's spinning that way if I turn my head will look like it's spinning that way so can spit in all possible ways right but the argument changes the second the particle is massless because it's moving at the speed of light I can never catch up with it okay so I can never stop it and turn my head to see that it's actually spinning in every possible way and in fact this is a remarkable fact the only spins that massless particles can have are spins in their direction of motion or oppositely oriented to their direction of motion so this is often called Calissa T instead of spin just because you kind of think of it as some kind of helical motion around the around the direction in which the particle is is going okay also the fact that the particle is is massless tells us there's very simple relation between its energy and the momentum that it carries if I have a photon this barrel along in this direction if it if it hits me or a block of metal or something it'll move the block a little bit the block picks up some momentum the amount of momentum that it picks up is exactly is just it the energy of the photon has is the momentum that it has the size of the momentum that it has a very very simple relation okay okay all right so okay so let's let's now try to understand why it is that that we have ink that we only have this tiny menu of possible spins and to do that I want to start off by thinking about what what seems like the simplest possible kind of interaction that I can have between two particles two particles come in and they go out and somehow and there's some amplitude for this process the words that we talked about before now look at this possibly depend on it can actually depend on a lot it can depend on the energy that these particles have and it can depend on the angle that it comes out at depending on many things could be a complicated function of the energy in the angle and we can't actually just predict it just from pure thought or from first or for some first principles but that's fine because the elementary interactions were allowed to have aren't to these four point interactions there are those basic three point interactions so let's think about what the kind of three point interactions that we can have and now this is an incredibly different story see if I have a massless particle moving along by it's very easy to see that by conserving energy and momentum it can't actually split into two other massless particles that are going out at some funny angles all I can do is split into two other mass's particles that are moving right in the direction of the first one is moving in so there's no dependence on any angle there's no angles involved here at all okay all I can do is split into two of them now could it depend on the energy well because of relativity can't depend on the energy if I go to some different frame of reference I'll still see that this guy is moving to the speed of light but I'll have a different energy so by the principle of relativity it can't be that this depends on the energy so it seems to depend on nothing at all doesn't depend on the energy doesn't depend on the angle in fact all it depends on are the spins of these particles a B&C and once you give them you can completely determine what that interaction is it's amazing okay this is an example of inevitability okay you just declare the principles of relativity and quantum mechanics and the kind the structure of this triple interaction is completely fixed just up to its overall strength is the only thing that we don't know all right so now let's return to the problem but so far we still have spin 17,000 particles floating around okay now let's return to the general problem let's say we want to see what happens in a more normal situation with two particles come in they bang into each other two particles go out there are some very general principles of quantum mechanics and relativity again that tell you very basic things like when can this amplitude become big it can become big if you can actually produce a real particle not one of these virtual particles that we're talking about but an actual real particle and when it becomes big this thing has got to split into sort of making that real particle and having it go out on the other side and doing that so remember these elementary interactions we know everything about we know everything about them because they're totally determined by the spins and nothing else and so this is now just a completely well well posed mathematical problem I have to write down see if I can write down some function of the energies and the angles that when it gets big it turns out to be representable in this way so it's now we have a completely beautifully that this is the consistency condition relativity and quantum mechanics forces it to look like that now we can see is it possible is it possible to make it work this is one of the places that you better trust me so we do have to go to grad school after all okay so after a year after about a after a year of grad school it's really it's just a one page argument I mean I could I could write out the argument for you in one page it would be nothing to it's a very simple argument but you do after all need to go to go to grad school for a little bit to understand this but it turns out that it has a dramatic answer that you can't actually do it almost at all except in these very very special cases the spins that you can have are zero 1/2 1 3 halves in - those are the only possibilities and furthermore and all you can pick then the only the only freedom that this guy's got to be unique you can have a bunch of these you can have a bunch of these you can have any number of these that you want in principle ah so that's it all you get to pick the only freedom is what is this menu exactly and what are those interaction strengths now if you want to once talk so it's a nothing in this talk is look like the things one was talking about okay if you want to is talking at this beautiful financial analog for 4 gauge theories and arbitrage and so on and so forth and so so nothing in in the description that I talked about looks like that the relation between the two of them is that what you want referred to as the beautiful gauge symmetries are a very convenient language for describing the physics that we are talking about in fact there's really convenient about them is the way I phrased the problem two things come in two things go out and you don't much care about talking about exactly how it happened in between but if you want to describe things in a way where you can give a picture for what happened in between with things banging into each other and so on so forth you have to use this very this beautiful picture that one described okay so so we've now learned whatever the underlying laws of physics are at long distances they must be described first of all the only interactions we notice are these little stick figure interactions secondly they have to be the only menu we can have a zero one half one three-halves and - well we appear to have seen in nature a little puzzlingly seems to only be a little subset of that we've only seen one half one and two for the spins so what about the eggs all right so now the story the Higgs actually starts by noticing an amazing difference between massive and massless particles with spin so let's say I have a massive particle of spin one this is just the argument we went through a second ago I can I can always stop it I can move I can I can move with it so it stopped and then I can see that it can spin in three different directions but the massless particle I can't do it only has two ways that it can spin so we said that we'd like to go to high energies and somehow ignore the mass forget about the mass it's not really relevant but we can't quite do it because there is this big difference there's three of these versus just two of these okay there is one extra way that something can spin when its massive that's absent when we try to describe it in a massless way there's one extra guy here when it's a spin one particle remember these W particles have spin one so the whole story is going to be about this one extra guy okay let's actually look at what that one extra guy looks like so let's say I have a W particle sitting here and suppose that it's spinning up like this but I boost it that it's moving along really fast in that direction well according to the rules of relativity it still looks like it's spinning up like that if nothing has changed if I if it's spinning this way well then it looks just exactly the same like that but let's say that it happens to be spinning in the direction in which it's now going to be boosted then loosely speaking this is not quite correct but loosely speaking if you've heard of things like length contraction or time dilation and things like that in in relativity the it's not really the spin itself gets bigger in this direction but roughly speaking the amplitude to find this particle spinning in the direction that it's moving in grows with the energy fact that goes like the energy divided by the mass of the particle in the limit as the energy is very very big compared to the mass so the ones that are that are that are not spinning in the direction of this moving at are unaffected but the ones that are start getting bigger and bigger as we go to higher energies now we're in big trouble now we're in very big trouble because let's take two of these W particles and Natta let's collide them with each other and let's look at what these amplitudes look like I told you before that all these are just small numbers one percent just tiny numbers everything is fine these amplitudes are like Q squared is around one percent but if they happen to be spinning in the direction that they're moving in then the the strength of the interaction is just one percent but the the amplitude to find them in that eight is growing with energy and so this amplitude actually starts growing with energy again so this number is small but it starts growing with energy again now we're in trouble because again if this amplitude gets bigger than one everything is nonsense probabilities are bigger than one everything is breaking down so that tells us there's some energy at which this just really goes goes to hell and you can be very precise about it the mass of the W particle is 80 GeV 80 times the mass of the proton there's a percent you put 80 there you work out when is that around 1 and you find that it's around 1 when you put some more numbers in when the energy is bigger than 1200 GeV ok so there's a real problem when the energy is bigger than 1200 GeV everything is breaking down we don't know we don't understand what's going on probabilities are getting bigger than 1 when we just collide these W particles together there are other problems of this sort if you collide 2w particles and produce top quarks again the amplitudes become nonsense bigger than 1 around when the energies are around 1000 GeV so we might have had this sort of naive picture from everything that we talked about before that here we are down here we've seen WS and Z's and everything else at energies of hundreds of GeV and then we just sail up to very high energies and somewhere near the Planck scale maybe we don't know what's going on at this gargantuan energy scale we don't know what's going on that's naive expectation but the actual situation was that something had new have to be happening right above our noses just within a factor of 10 of where we'd been already just from this argument this we knew again no ifs ands or buts all of this was just nailed and forced on us by everything we understand just relativity in quantum mechanics and nothing else ok so what could it be well ok the most the most naive thing that you might think that it could be is that well ok something new has got to happen at around 1,200 GeV ok it's a little too bad because we're stuck down in hundreds of GB it's a decade these decades take you know 20 or 30 years for experimentalist do I get to say might just think oh well you just sit there you wait for experimental so get up there we'll discover all sorts of new stuff but some theorists were more impatient than that and they decided to try to see whether they could see some effect of this fact that everything was breaking down at around 1200 GeV if they could see it in a more indirect way so for example here are these these this L stands for those those spins of the WS that give us trouble so I told you there's also Z particles so we can have Z particles and Z particles here interacting virtually with these w's that pop in and out of the vacuum and this gives some correction to the way this Z particle couples to electrons let's say it's a tiny correction but details theoretical calculations around 1989-1990 were done and they found that again if we assume that there's nothing new till around a thousand GeV that there are one percent level Corrections one percent level Corrections to how the Z couples the ordinary matter the tiny effect okay and this were difficult to sort of tour-de-force theoretical calculations that were done by theorists in this in this period to find these tiny Corrections our experimental colleagues were even more ambitious they said great thank you very much you gave us a target we should expect interesting one percent level Corrections so we're going to go measure these things to a tenth of a percent accuracy okay and they did that so in exactly the same period 1989 to 1991 people measured exactly these couplings between Z's and electrons and also a related effect adjust on the masses of the W and the Z particles and they measure them to 0.1% accuracy and what they found was amazing so here are some these are the size of these deviations and units of 0.1 percent what they found is that the fear is what they found or some sort of experimental error band ah but but what you got from assuming that that we just we just went all the way up to a thousand GeV and something something new happened up there was far outside the experimental error bars so you would predicted something that was up 1% big sounds tiny the experiments are better than that that measures to a 10 third percent it ain't there okay so this is this is quite remarkable because it told us that actually something new had to happen even earlier it have to happen even earlier than 1000 GB you'd have to happen beneath around 200 GB or so so we need something new and right around the corner something new and what is the job of this something new it has to solve this problem we have these amplitudes we scatter these w's the probabilities are getting bigger and bigger dangerously bigger and bigger something has to change this calculus something has to change this argument something new has got to be there instead of interacting like this has got to be some something new let's call it X so that when you add this way of doing it and this way of doing it the amplitudes don't grow anymore okay similarly I told you we had a problem with W is interacting with top quarks well there have to be something there there again so see whatever the heck this thing is it has to have some interactions with the W nice to have some interactions with the top quark all right so now now let's now we've we know all all these constraints about what possible theories can look like so let's ask a very basic question what could the spin of this particle be well it turns out that the one-half three-halves and so on those those are just ruled out for a very simple reason so it could be 0 1 2 3 4 and so on well it can't be 3 4 all these higher ones we threw all of them out already it can't be 2 because we said there's a unique spin to particle it's the graviton it can't be anything else it could be 1 it could have been 1 but that's a little funny because we have some massive spin one particle but this whole problem that we got was from a massive spin one particle so we don't want to have a sort of Russian doll of like introducing a spin one particle and then introducing another guy for that and keep going on for other it's not ruled out but it's very ugly and strange so we're left with a unique possibility it has to have spin 0 ok when this guy spins 0 it's called the Higgs this particle is called the Higgs so I want so this is it's an interesting point if we go to very high energies this what we call the Higgs particle and these longitudinal components of the W and the Z particles are actually united together they're there United together into one object and this one object interacts with W's and top quarks and everything else by all the usual allowed interactions that we talked about or okay now this was a brave proposal because as you've seen no one had ever seen a spin zero particle in nature before okay so it's an it's an interesting situation just from the consistency of the laws we could have it but no one had seen it before and yet we seem to be led in deneva get in order to deal with this problem so you make the proposal and of course it was discovered on on July 4th but I want to just say a little word and I won't go go through these pretty pictures of how the of how the LHC works well this is not a pretty picture anyway but so anyway we collide particles at very high energies and we measure them in gigantic detectors with European Union issue people smiling in front of them always in in pictures but I want to talk about how it was that the Higgs was actually produced at the LHC because because this shows how completely constrained this entire story was again no choices there was absolutely no other way that things could have gone how do we produce a Higgs at the LHC we bang protons into each other and I didn't mention it but the Higgs has these big couplings to W particles and to top quarks it has much smaller W and Z particles into top quarks there's much smaller couplings to everything else they're also nailed but they're much smaller and those things don't seem to be inside the proton the proton is up and down quarks and gluons in it well you produce it through a through a quite indirect way to gluons come out of the proton they excite a top quark in an antitype work out of the vacuum and now that top quark can talk to the Higgs now remember that interaction strength is completely nailed from our arguments from what the purpose in life of the Higgs was there's no choice for what that coupling could be and so the rate for producing the Higgs is completely nailed we can't do anything about it so it's some number we can't change it by a factor of two here or there it is what it is okay okay now this unfortunately doesn't come out wearing a nametag saying I am the Higgs the Higgs particle decays in a blink of an eye and around 10 to the minus 22 seconds to ordinary part goals uh but when it decays in it when it decays the way wants to do most of the times these these things called bottom quarks it's very very hard to see at the LHC is maybe made around one hundred five hundred thousand Higgs is up to now that's that but that sounds like like a lot but when it decays into these bottom quarks like it does almost all the time unfortunately the bottom quarks are made billions of times through much more ordinary processes so this is a very very hard way of seeing them so you have to see it in a much more rare way the Higgs can again through one of these virtual processes producing w's then decay to two photons this coupling of the Higgs of the W is also nailed these were the two couplings that were completely nailed from our considerations we could do nothing about it so the rate that this happens is nailed the rate with which it's produced is nailed and so we have to get that answer and nothing else the only thing we don't know is the exact amounts of the higgs particle but from the these precise measurements we've done a long time ago we knew that it had to be somewhere between 80 to around 200 times the mass of the proton somewhere in that range that's all we knew and that's where it was seen in exactly that range so here's the higgs decaying to two photons the way you can see that in the case that it's the higgs doing it and not some more normal process and if you make the Higgs and at the case - a couple of photons every time it does that the sort of energies of the photons have got to add up to be the mass of the Higgs so more ordinary processes will spit out photons left right and center but the Higgs will keep piling up in one place again and again and again and so you should find if you look at events that have two photons you just find a bump in it okay the size of this bump how big it is is completely predicted by these considerations and it worked so this was I think a triumph or experiment of course but also a triumph for theory tells us that physics works and that belief in principles paid off so we saw that what we are allowed to have on general grounds where zero 1/2 one three-halves and two we hadn't seen zero and three-halves we were led to saying this thing has got to be there we've never seen one before but by these arguments by our little detective story it's got to be there and by God it is it's allowed to be there it can be there it is there okay and that's what's exciting about the hates it's the first really new particle that we've seen it's the first particle we've seen that has spin zero okay the other ones had 1/2 and 2 all right so um let me just end the the Higgs story by now relating a couple of the metaphors that you've probably seen the number of times one metaphor so no we're here we use a lot of the usual language the Higgs gives mass to particles the Higgs is like some fluid or molasses that particles moving they get their mass from interacting with it this molasses metaphor is just truly terrible I've used it myself so but it's terrible it's misleading worse than misleading it's wrong ok so this is just just really false there's another picture that you often see which is which is perfectly fine that's correct you might see pictures of things that look like these little Mexican hats and we say the Higgs could sit up there but it's not stable and it rolls down there if you haven't seen them don't don't worry about it but this is a picture of using the language of what's called broken symmetry and this is perfectly good it's useful it's a correct it's a good language for describing the physics it's one language for describing it it's not there are other languages for describing and what we've talked about here has been another language we didn't need to use any of that and the advantage of talking about it in the way that I've talked about it here is that you see why it's necessary ok it's not just something that we're though that we like but it's really it's really necessary all right so um so I'm I'm I'm done I'm not going to have time to talk about the Higgs mysteries because Robert is walking up but but let me just say let me just say one thing so something which is that there are real puzzles associated with what the Higgs the fact that 2 is not equal to 3 is very important and the fact that 1 equals 1 is even more important but but but something that you've probably heard many times in talks like this is this idea of super symmetry that that there's difficulties with the Higgs and supersymmetry is a wonderful way of dealing with these difficulties with the Higgs the language that I'm using in the stock really drives the point home I think even more in an even more in an even more direct way you see we have this menu 1/2 1 & 2 we have the allowed menu 0 1/2 1 3 halves and 2 and we saw that nature seemed to have only used this small portion of them until it came to the Higgs and it used the zero but the part of the talk that I can't talk about because Robert will kill me is says that there's lots of mysteries associated with that and then if you just look and say jeez why don't we see that three halves well it turns out that if you go through this one year of grad school exercise you discover that that three halves is associated with this idea of supersymmetry okay you have to have this idea of supersymmetry associated with that three halves this doubles the world does all sorts of wonderful things but amongst other things that completely solves this problem it solves this particular mystery associated with the Higgs and there are ways that we can and we are looking for supersymmetry at the and we are looking for supersymmetry at the LHC we haven't seen it yet but but it's something that that we are looking for but all I want to say for the purposes of this talk is that the reason why there's so much excitement about supersymmetry is we doesn't mean that it has to be right but it's the last remaining thing it's the last thing that nature could do in principle that we haven't seen it do and and and we saw something fairly dramatic what the Higgs already we saw the zero option used so it's not crazy that it's going to come along with the whole thing and we'll finally see the whole panoply actually used by in in the way nature works that's another example of the sort of thing we love in theoretical physics the ideas don't have we don't know if necessary they're realized in nature but there's something rigid and perfect about them and inevitable about them just as theoretical possibilities and thinking about these thinking about what's inevitable and rigid leave just that first of all it's a very strong constraint on theoretical speculations we can't mess with the rules that we have already and it leads us to a tiny set of possibilities for what my ax maybe they're okay and maybe one of or some of them are hopefully realized in nature okay so let me just end by by saying that no no this is really ending that space-time in quantum mechanics really framed the central dramas of the 20th century and really have taken us shockingly far we've seen the story of the Higgs is the last example of how shockingly far it took us but but in a sense this whole story of the Higgs is the last one of the last embers of the set of ideas that we dealt with an understood in the 20th century the real drama oh and and again these ideas inevitability rigidity and fragility and beauty are are we've seen I hope over and over again in this talk but the real drama of the 21st century are really new questions we saw that it's really relativity and quantum mechanics this picture of space-time the ninth son gave us in quantum mechanics that's been so shockingly rigid and powerful so the next set of questions are where do these things come from see that's one thing I didn't question I just took space-time and quantum mechanics and all the rest of it followed so this is really the next set of questions what's the deeper origin of space-time in quantum mechanics and this is what you should ask your friendly neighborhood strength theorists to a tell you about okay and in fact I really hope that if you you should stay tuned for I as public lectures sometime between 2020 and 2030 and we might have a little bit to say about these questions thank you very much well another description I've heard of demise as the fifth force of nature which work well and thank you for having this trailer of the second parrot talk okay so fast I want to we are a bit constraint in time which I want just took an opportunity for say one question is anybody volunteering to to ask pressing questions over there I think there will be microphone so it's not a question it's a comment I'm probably one of the few people in the room that's not a physicist but what struck me with the words your choice of words inevitable rigid fragile and beauty is they all conjured up an image of truth to me yeah and so I wanted to share that with you know in other talks in this menu I've used this opportunity to say how incredibly apt the seal of the Institute is which has you know truth and beauty sitting right next to each other actually interestingly you know that they're two relatively scantily clad ladies it's truth which is which is naked in beauty which is which is veiled in that via in in in the seal that may tell us something about the kind of work we're doing here but uh but indeed yeah everyone everyone everyone who works everyone who works in this subject knows that you know we're all we're all very very very we have very poor intuition for the way things work some of us are much less talented than others of us but it doesn't matter so long as they're somewhere in the basin of attraction of the truth the truth is an incredibly powerful thing that so long as you don't fight it sucks you in towards the swords the way things things things work and we really have it on our side yeah truth of the cap with a capital T absolutely oh thank you perfect closing segment of this done this is thank you very much thank you

Channel: Institute for Advanced Study

Views: 20,692

Rating: 4.8271604 out of 5

Keywords: Nima Arkani-Hamed, Lecture, Particle Physics, Large Hadron Collider, LHC

Id: hcPW7lyHpIc

Length: 75min 38sec (4538 seconds)

Published: Thu Nov 29 2012

Reddit Comments

[u/bobbincygna]

what's the knowledge needed to understand this lecture?

[u/[deleted]]

Thank you for sharing. Id upvote the shit out of you if I could do it more than once.