Video Infoblog: A Thin Sheet of Reality: The Universe as a Hologram

 

 

 

Transcript

 

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��.. Clapping ...

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Here we are again, good evening to you in beautiful gorgeous summer night in New York and here,

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this place is full of people who wanna talk about holograms and wao...

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Yeah World Science Festival so grate, my name is john Hockenberry first of all I am college drop out, new guy who is gonna hang out with nobel physicists tonight, perfect for this job

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Oh my god... how did I get here! But seriously, you know we think of, this season is World Science festival, this the beginning of June

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the weather stars to get great, you know tonight at Brooklyn Bridge Park its supposed to be one of best viewing nights in Newyork and there aren't many really fabulous

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viewing nights in Newyork, so I urge you to do that, I mean its a beautiful clear night Every body is out there, its kind of like prom season, we think of the world science festival as the prom

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for all the scientist who; may be they didn't get any dates; didn't know there was a prom and I actually

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pulled our panel tonight, three clearly did not go to the prom; didn't want to talk about it and one

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didn't remember at all, you may be able to figure out who is who tonight.

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I am actually perfect for this gig for another reason because I actually inadvertently helped to solve

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one of the most serious problems in Physics, back in the 1970s. I was on a team that helped to do that,

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I was enrolled in University of Chicago, as an undergraduate and I tested into the top science section

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basically junior of science in my freshman year, and it was taught by a prerogative; David Triumph, one of the

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nobel orated university of Chicago, the late David Triumph brilliant physicist and part of the

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university of Chicago program which give us Enrico Fermi and so many others and Chandra shekhar and

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I was in this program and very excited, I go to the first lecture and it was taught by one of these prerogative

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central European fellow, I can't remember his name now and it will become clear why; He said!

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Hello everyone, its great to see all of you here, we have very serious problem in Physics, the problem is:

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Simple problem but serious problem, "it is too many physicists"

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So in this course if you are getting B/B- you will get F. If you are doing B+/A, you will get A.

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I went into the news business and thereby helped to solve the very serious problem in Physics.

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��.. Clapping ... to many Physicists so and a lot of the panelists tonight possibly grateful for that, so you are here to talk about and to listen to

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one of the most exciting, fascinating also difficult principals that now being kicked around in physics

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and cosmology, the holographic effect and it evolves a couple of concepts that actually we have a lot of

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intuitive; sort of sense of and I want to present two of those tonight before we introduce the panel and get

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started here. One is the idea of information, we think we know what information is right?

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Information is very very; like you know information right? Now that isn't the Newyork subway system right?

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But it is enough information to specify; how to get from point A to point B and if you understand how to read

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the subway map, you can get from point A to point B. The information isn't exactly the same as the subway

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but if you don't have the information the subway is useless to you and some how its sort of maps directly,

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it is a map right? Its maps directly on to the subway and of-course now the subway map, nobody has one of these right? its all on your smartphone, which means its stored on a tiny piece of

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silicon, so therefore the volume of this (hard copy) can actually be map directly to a volume, you know

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one millionth the size, take for example this (book) anybody got these anymore, no? This specifies the

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number of synonyms, I don't know what the hell it actually is but it is the source and it actually also

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fit in a tiny piece of code in Microsoft word. We got here just the Oxford shorter English dictionary, information

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I am gonna set over here just to remind you what information is all about, now information, The dictionary isn't the English language right? the space, the universe of the English language is all you

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people talking, will you talk now, just talk, just turn your neighbor and say hello, how you doing? right there see?

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That is the space, the universe of English language that you are hearing it is not the same as this book

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but its sort of maps on to this book and there is enough information in this book to make predictions about

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what it is you saying so that if you actually talk to me I know what the hell it is that you saying.

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Unfortunately; I probably won't know what the hell there is most of the panelists are saying tonight so I may need

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you help with that. Nevertheless there is information in what they say, the information maps on

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to a space where we can make predictions, it is information that allows us to be conscious being

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it is information that allows us to be living being if you think of DNA's information now the information

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we are gonna talk about tonight is much more complicated but the idea of information as a map as a specification of a much bigger space it is sort of the beginnings of we are talking about here.

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You know these holograms right? you know; clap if you know what a hologram is ��.. Clapping ... right.

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I just said: clap if you think, you know what a hologram is.

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Let me introduce our panel please welcome Raphael Bousso ��.. Clapping ... ��

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Let me tell you few things about Raphael, Raphael Bousso is a theoretical physicists at University of California Berkeley. He is recognized for discovering the general relation between curved

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geometry of space time and its information content, a key idea of the holographic principle.

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Please welcome next panelist: Herman Verlinde ��.. Clapping ... ��

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Herman Verlinde is Physics professor at Princeton university, in 1998 Verlinde recieved his PhD

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under the supervision of Gerard 't Hooft, Verlinde is renowned for his contribution to string theory

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and its application in cosmology, blackhole Physics, some of its current work explores gravity

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in context of the holographic principle. Our next panelist is indeed Nobel prize winner Gerard 't Hooft ��.. Clapping ... ��

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Gerard 't Hooft received the 1999 Nobel prize in Physics for his doctorate work in theoretical Physics

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He is professor of Physics and of his many achievements, he was the first to propose the idea that would later become known as the Holographic principle.

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And finally our fourth panelist Leonard Susskind ��.. Clapping ... ��

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Professor Susskind is Professor of theoretical Physics at Stanford University and the first to give a more precise

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interpretation of the holographic principal using string theory. He is well known for his book on the topic of

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the Holographic principle, the black hole war might battle with Stephen Hawking to make the world safer

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for quantum mechanics. Its a fantastic book. I highly recommend it.

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Please welcome the Panel. ��.. Clapping ... Back in early 1970s Stephen Hawking wrote down a astonishing equation, it would include relativity

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it would include quantum mechanics and it would include information, Hawking rather simple equation

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brought us a step closer to understanding the relationship between quantum Physics and black holes

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When an object crosses over the edge of a blackhole's event horizon, the object enters a realm basically

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of empty space of darkness and continues to be dragged toward the center of blackhole,

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toward we call the singularity where it gets crushed out of existence. Every object in some sense contains information, because it contains a very specific arrangement

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of particle so where is the information that describes the arrangement of those particles, where does it go?

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Hawking's description of this process was that; the energy remains but the information disapears

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For many years, for decades people wondered; is Hawking right? Is the information obliterates

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and disappear from the universe or is it still there and perhaps can be, in some way retrieved?

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the destruction of information was counter-intuitive and didn't match the rest of the things we knew

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in all part of Physics we have situation where information doesn't get destroyed so it was a bit puzzling

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This debate furiously went back and forth up through the 80s and into the 90s when people

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finally began to articulate, this new principal, this holographic principle and what it said is that

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all the things that were falling inside the blackhole were somehow captured in a preserved image

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at the horizon itself. So if the information is not lost on the surface, the information is lost inside because

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they are equivalent. All the information about those objects, what they were like, in their three dimensional

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existence was preserved or encoded on the surface of the blackhole and that is little bit like a hologram

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well that suggest that may be that idea, may apply more broadly to the universe as a hole, may be the three

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dimensional objects, us, everything in the world around us, may be all of the information in these objects

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is carried, is smeared around a distant two dimensional surface that surround us and we are just, in some sense,

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holographic projection of that distant data.

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The holographic principle tells us some thing quite astonishing, it says the ideas of volume,

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that real world in some sense might be a kind of illusion.

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So, are we real or we just holograms. Lets begin with that but in fact lets first of all remind folks

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You guys were direct participants in that argument that was described in that film which I think fairly

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characterizes difficulty scientists have, not only in sort of grasping and fully understanding this

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holographic effect principle but also explaining it. Leonard Susskind! what was it like to get into essentially a pretty big cosmological argument

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with Stephen Hawking, and be careful because Hawking is one of the my wheel chair boys and we are really tied

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What was it like; it was fun and it was frustrating and it was incredibly frustrating

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Stephen has a view which was very very difficult to argue with. His idea was based on very very sensible ideas

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a blackhole is a place where nothing can get out of but things can fall into it and the things can fall into it

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and they can't get out, they are gone but then the blackhole evaporates. Stephen had proven that beyond

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any body's doubts and so things fall into the blackhole, they can't get out, the blackhole evaporates,

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puff its gone. Just exactly as Brian said. It was unassailable, there was no way for argue the case

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and yet some of us particularly Gerard't and myself very very strongly felt that this really undermine everything

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that we knew about Physics. Everything that we know about Physics today and even much earlier was based

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on principle of Physics which is so basic that we sometime forget to mention it to our students

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Its the idea that information never disappear, and I will tell you what it means, information means distinctions

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distinctions between things, Hydrogen atom is not the Oxygen atom and Oxygen atom is not Hydrogen atom

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there are distinctions between these things and there was a very very basic principle of Physics that

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distinctions never disappear. That they may get scrambled, that they may get mixed up

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but if you start with one configuration and you let it go or you start with a different configuration

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which has different information and you let it go, they will stay different and Stephen was saying

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exactly the opposite, no matter what you throw in the blackhole and in the end you get out exactly the same

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thing. It was extremely difficult to see what was wrong with what he was saying, it was even harder to

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make him understand that there have to be something wrong with what he was saying so it was very very frustrating but at the same time it was very exhilarating to come up against this

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basic problem of conflict of principles. And if anything can break the impasses in Physics if there are

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no experiments available, its conflict of principle. When conflicts of principle arise

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that's when major new paradigm can shift. And that is excitement, that's really the excitement. Gerard't explain to me why this problem with Hawking, this; you know the information can't go away as it seems

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as though Hawking mathematics suggest it does? its different from, something like say, conservation of

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mass and energy, where mater can neither be created nor destroyed. Its different than that right?

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Yes it was a very fundamental problem, and way I always saw it is; Hawking was using quantum mechanics

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in particular quantized fields to derive his result. So quantum mechanics went in as starting point number 1

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and than general relativity and everything else, and use of that to derive the blackholes radiate particles

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from that it was derived that it was information and there was information disappearing.

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Well in fact information disappearance is at odds with quantum theory itself. So he used quantum theory

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to derive result which basically was at odds with quantum theory, so there had to be

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a mistake some where. I shouldn't call it "mistake" because what he did was by itself mathematically

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correct and nobody doubts that but the final result had something in it that couldn't be true so this is what,

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in Physics we call paradox. And like my friend Leonard has been saying as soon as we encounter a situation of

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this sort in physical world we were very happy actually. It is a paradox it means there is work for us to do

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and we have to clear things up. And if you look at the past, you know quite well that when people start to

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clear up paradoxes, new discoveries are being made. So you guys are friends? So it seems in several cases and that's why we also excited about this thing. Is something wrong?

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Derivation itself seems to be flawless but there is some thing wrong anyhow with the result. You guys are friends then?

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Of course we are. Yeah. Herman! Let me ask you a question just about this issue of information and then I want you to go back.

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I definitely want you to go back. Why does the universe need information. Why does it need to have

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this information. why does a rock need some sort of information or image?

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what you call information, we as physicists would just write such terms in equations right.

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We think of physical world as been driven by mathematical formulas, in these formulas that have

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what we call; degrees of freedom. So things can be this that or that. Oxygen or Hydrogen he given us example.

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All these things gone as equations and we are used, particularly in quantum mechanics to the situation that

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If two things start up differently, they end up differently, that's a fundamental notion in quantum theory.

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We can't get around it. you can't have two different states adding up after a while to be the same.

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That's violates the principles of quantum mechanics. Now quantum mechanics itself is

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not such a sacred theory that may be avoid violations of it, but then we want to know about this.

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We just don't want to say, well you know, we have to clear that mess up later. No no the mess has to be cleared up right now. If there is a flaw of this sort in a result, we want to know about it.

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So what Hawking was saying; two different blackhole start out differently and one of them has tea pod falling

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into it, in other an old shoe. I saw this movie and if tea pod falls into a blackhole or a old shoe falls

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into blackhole, that's different, tea pod is not the same thing as the shoe. Nevertheless after a while

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they look exactly the same according to Hawking. You see that violates our equations that can not be true.

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There is something wrong, something went wrong on the way and we want to know what it is. Thanks to referring to that, because I can't tell you how hard it was to get the tea pod into the blackhole and then to get the shoe

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I realize it. Sometime we just get the tea pod, we said get rid of shoe too, and that was really hard. Yeah Herman please

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Ok, Let me first follow on the, sort of the, because you were asking how was it to have a debate with Hawking,

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that was kind of you question, may be tell a little anecdote about how it was, in part of it, of course

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all about science and we are all friends, even if we disagree about the science. But Hawking is very spacial

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person where he can think very deeply about questions but he also has handicap. He can not speak so he has to

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speak by typing words and some times the debate would go like this and then even argument

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would be given and then Hawking response would be one word - rubbish -

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- Very hard to argue with- and that's very hard to argue with and you know, when I say rubbish no body pays attention you know

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But when Hawking says "rubbish", its silent and you lost the argument at that point. Capital R, its a big Font there

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Yeah right. When Hawking says it. Alright so Hawking says rubbish to you, do you like go home

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and tell your wife; Hawking said rubbish to me, what do I do or you like to the blackboard or just sit down to computer? what happens? You go on with because you believe in your argument.

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The other question about information, the thing which I like sort of as a way of explaining what information is;

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we live right now in the age of information this is the information age but the type of information

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we are talking about here, you say, well its more complicated but one way of imagining what kind of

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information we talking about is; I like the movie "The Matrix" where there is virtual reality where actually kind

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of nightmares for myself when I was young. What if the whole world is just a thing that's been projected on my

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brain or actually for all of us that are sitting here in this room, and who knows might be its just a computer

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that makes us believe that we are real and the kind of information that we are talking about is really sort of

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what is inside of this computer, imagine you make this hall here with all the reality of being able to do

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experiments. Things fall, you collide things, things happens exactly the way we thought and think about

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its happening in Physics. But its all just zeros and ones and a computer. And in principle you can quantify;

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how many terabytes, how many gigabytes, how many, I am not sure, I forgot what comes after gigabytes but there is information in that computer and that's the kind of information we currently talking about.

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So when you say information, you say that physicist believe and cosmologist believe that it is possible

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to map every aspect of reality that we are experiencing here into some sort of stored code that specifies

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preciously everything that is happening here, what people smell like, who is mad at who, who is wearing

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like dirty shoes and what they are even thinking about.

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You can imagine that's the way it goes. Now just its something scientist or imagining it or does quantum mechanics insist that there must be so?

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Raphael! Quantum mechanics in a way is based on information. its a theory of information.

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The way that we would describe the world and if the room being full of people or no full of people

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and electron being in this place or that place. These are different states as we call them and its; as if; you know,

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you put one letter on the page or you put a different letter on the page because its different, it conveys information. So where a particle is a way of conveying information and in fact quite literally when we right some thing on

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a page we put particles in particular places and we thereby convey information so its not very efficient

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compared to, Lets explore that for a moment, Victoria do you have Rapheal's slides.

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Put up his first slide over here because as someone who understand mathematics poorly,

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The understanding that I had was that; as you go, say you are looking at the coast line of Massachusetts

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and you are looking at it from a satellite and you see one line, but then you come closer and then you begin

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to trace every little indentation and then you get even closer and you trace even any more indentation,

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try to specify down to the atomic level that the amount of information in the line that traces the coast line

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is actually unbounded and infinite. What is it that you have discovered?

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Well that is not, its not infinite, there is a limit. - And so how does this, how did we begin with this picture here.

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I think there is very important thing that maybe we need to say in order to get from blackholes to this - Sure -

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I was actually not part of this debate with Hawking, I became his student two years later but

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You look younger as a result, I think As a result, yes its certainly age these gentleman here - so I -

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its recently the reason we are ordered this way, we came in we figured Rapheal could walk the furthest and

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We decided, we are gonna leave you here when we -

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And Hawking could be here, you see, got me so Yeah he was here last year

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Anyway so these gentleman had, you know the crazy insight that when information is dropped into

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a blackhole, it is not in fact lost Even though naively you would just think ok now its in this blackhole its somewhere when we can get to it. They insisted that you still have to be able to get to it.

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Which. you know, let me make this tell them so easy, but it wasn't that obvious. it was an incredible intuition

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And for that to be true, that, if you throw a phone book into a blackhole that later on you can figure out

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whether it was the Newyork or Chicago phonebook. Two amazing thing have to be happen.

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First of all Hawking have to be wrong about the idea that, no matter what you throw into the blackhole,

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same thing come out. very loosely of putting what he said but that's the basic way information would be lost.

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A second amazing thing had to happen, which is, you know, it takes a long time for a blackhole to fizzle away

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and disappear and return potentially, return information to you, supposing Hawking is wrong. And in mean time

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you got this big flat blackhole sitting there. And what had to be true was that, while that big flat blackhole

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sitting there, that blackhole itself contain information while its still sitting there and hasn't fizzled away yet.

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Alright, so the question- And for that to be true, there had to be a limit on how much information there could possibly be in the region that was occupied by the blackhole.

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Because you can presumably always convert that region into a blackhole.

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Alright, so lets backup for a second, so Hawking suggest that the information is gone. You say that can't

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possibly be true, Hawking says -rubbish- and then you go about saying: we are gonna find

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where that information actually is. Leonard! before we get to Rapheal's slide here, where did you find or where did we find that information,

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that Hawking says is gone in the blackhole is actually stored?

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Ok so, one of the things that we found is, I am sorry to say this John but turned out to be a bad question

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Ok, That in a certain bit of information don't necessarily have locations or at least they don't necessarily have

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locations which are objective and same for every body, no matter how they are moving.

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Ok, I am all about that questions The notion of a bit of information is a good one, we believe it, we believe distinctions exists

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and distinctions persists. But the notion of where that bit of information is located turned out not to be a good

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what a physicist would call, invariant question. It might depend on who was looking at it.

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Now let me give you an example of where it is a good idea. If an atom decays inside the sun, everybody will agree it happened inside the sun, it doesn't matter if you are

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moving relative to the sun, it doesn't matter if you are far away, if you are nearby. Everybody will agree if they do

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the calculation, and see what comes out and agree, the atom decayed inside the sun, the thing happened inside the sun.

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Blackholes are different and what we found is the whole notion of whether something happens inside

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the blackhole or it happens just above the surface of blackhole, surface means in the horizon, is a question

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which is observer dependent. Somebody who falls into the blackhole may have all of the experiences of seeing

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the event happen well in past the horizon. Somebody standing outside the blackhole will reconstruct

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out of the Hawking radiation that, that event actually happened outside of the blackhole. So the answer to

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your question is; we didn't find out where the information was, we found out that it was a improper question

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The bits of information don't really have locations of that sense. And how do you know that they weren't destroyed if you couldn't find them in any particular location.

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Well, eventually a lot of the power of string theory and other mathematics came to bear on it and confirmed

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that there was no expectation that would be destroyed. But as; can I call you Gerard't, its so much easier.

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Ok, as my friend Gerard't here says, I spent years learning to say Gerard't; but I never-mind.

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I am totally fine with Gerard't, totally fine with it.

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God I am 71 years old and I forgot what I was gonna say You were saying that issue was where it was

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and the in-variance of the question meant that, the variance of my question meant that you wanted

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to basically change the nature of inquiry. yeah you asked me, how we know and, I think the answer was given by Gerard't that, so much would break

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down in Physics the whole structure of everything we know about Physics would breakdown and disintegrate

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if even you open a door for tiny little bit for the idea of information to be lost. Once it can be lost, you can

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promote that and make it worst and worst and worst and worst and eventually the whole structure of Physics,

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as we know it, will breakdown. There was somethings you can't have a little bit of, You either have it

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or you don't, you know, we all know about pregnancy, but let me give you another example. In mathematics

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can you have a theory, a theory which means of mathematical structure, arithmetic or what ever.

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Can you have a theory which is approximately consistent, its almost completely consistent,

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well you might have some structures some set of axioms and you derive, you let your computer run

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and derive ten thousand of theorems from it and say all approximately consistent, only four of them

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were inconsistent with each other. Well no, mathematician will come and tell you, once you have any inconsistency, you can use that inconsistency to promote that, anything is inconsistent

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with everything else basically. I think the same thing was true about information lost

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once you have it, once you have it in any form at all, you can imagine situation where it would undermine

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basically all of Physics. And that's what, I think, that's what Gerard't thought, that's what I thought and that's what Stephen didn't think

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So we sort of battled heads against the wall for a while. Alright, so how in my imperfect questions creating way,

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can we get to the point of either, if not, where was the information, how did we learned conclusively that it

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wasn't destroyed and that if, the phone book went into the singularity that there was a way to find out

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if it was Chicago, or Amsterdam or you know, Seattle

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When ever I encounter situation like this I try to approach it from all possible angels

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Particularly angels of my neighbors here will not be prepared to look at, to see what can we do,

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we have as I said a paradox here and the resolution must come from totally different point of view then previously.

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Now one thing was that quantum mechanics was used to derived the result, quantum mechanics some how

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failed to agree with, by far so there was something wrong so my attitude was start from other end,

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now lets assume that blackhole, as a hole, agrees with anything we know about quantum mechanics.

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That mean information in is equal to information out. Its that simple basically in quantum mechanical sense

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so that ought to be true. As soon as you believe that this is true, its a relatively simple calculation to find

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how much information there is in the blackhole. And you do the calculation, you find the amount of information

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in the blackhole is exactly equal to its surface area. Its like putting bits and bytes of the computer memory

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on the surface, every bit, every byte of information occupies very precise amount of surface which is then

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calculated relatively easily and that tells you big blackholes contains a lot of information,

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small ones contains a little information, still enormous amount in any absolute sense. That was very clear

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conclusion; how much information there is in the blackhole. But the question; where the information is something else again.

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Alright, let me guess; just backup here, so all you got , if you got your blackhole to study, at least not to find

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where the information is but to figure out if there is a quantity of information that could sufficient to specify;

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what goes on in this blackhole. You got your surface Not the sufficient; exact quantity itself Exact Ok there is a few bits hanging around aside but apart from that,

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the total quantity of information is very preciously calculable.

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But all you got is the surface of blackhole, so you got a test; could there be enough information on the surface

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to specify what gone into the singularity and what is happening beyond this event horizon, that's the question right.

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Well the question was answered by this assumption that blackhole should obey quantum mechanics

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once you made that assumption, you find that not only information seems to went in and out of the blackhole

34:03

but every thing in its vicinity should be mapped onto its surface in bits and bytes.

34:09

Its like saying that surface is a hologram of the immediate surrounding spacetime.

34:15

So a X dimensional object can specify an X+1 dimensional object.

34:24

Are you getting in this here, is this working for you? We are cool right, alright alright good, you are all with us. Ok

34:31

So the surface is two dimensional -Surface is two dimensional But surround spacetime three dimensional -Which is exactly what a hologram does

34:37

You got your two dimensional star wars movie and your three dimensional looking princess leia who by the way,

34:45

did have prom date, I believe, and so but is that an allusion, you know in prospective, its basically,

34:53

you creating an allusion or is it actually one to one mapping of all the information of the reality

34:59

on to the 2D surface that gives you, your 3D reality? Herman!

35:04

Yeah, again talking about mapping; then we don't know exactly works at this point.

35:10

But I would say that the principle that turns out to be very powerful int his context, I call it Rumsfeld principle,

35:19

and its basically saying well; its better to deal with known unknowns then with unknown unknowns.

35:27

He was bad at all of them by the way, yeah right.

35:33

So the unknown unknowns are stuff that you lose and you don't know that you have lost it.

35:38

If you throw something in a blackhole for all practical purposes, you have lost it, you have lost the information

35:46

But what we are talking about exactly that, we know that we lost it, again, I don't remember what I ate for

35:52

breakfast yesterday but I knew I had breakfast, so at least I know how much information I have lost

35:57

by having a bad memory and so the fact that we quantify, how much information is in the blackhole and

36:06

that its measured by the area. That turns out to be surprisingly, the key insight. So knowing how to quantify

36:14

if you don't know is a deep principle.

36:19

Alright, I think, yeah that's actually starting to work for me, lets forget your slide Rapheal for the moment,

36:27

if you don't mind and go to Leonard slide, which really gets us from this idea of; there is a bunch of information

36:34

and its maps into something that we might think of as a three dimensional image Victoria can you put Leonard's first slide up; Ok, what is this here?

36:43

That's a microscopic picture of the film of a hologram which in fact I made up myself with Microsoft paint,

36:54

so its a fake. But its about what it would look like. its about what if you look through the microscope

37:00

at the film, not this thing that is being described by the hologram but by the piece of film itself,

37:06

it would approximately like that. And so then if you put light through it in some particular way

37:12

Lets us sort this first, Its got some information in in it. Its all scrambled. Its impossibly scrambled you can't look at

37:18

this and see what it is. Anybody any guesses; what the image is there?

37:24

Anybody want to guess... What? Leonard Susskind ... good

37:30

I think guess down here. Ok great so - It is a fake

37:39

Anyone see puppy, Anyone see pup, Little Horsey No, no horses. Ok Alright; lets see

37:44

Ok, going through this next one. -Lets go to next, here is it; stand by folks This is another fake, I also drew that myself Alright - alright

37:53

So if you do the right thing with hologram, namely shine light on it and so forth. It will reconstruct an image.

37:59

So you got the flash light, may be this is obvious with flash light going through the film and somehow

38:06

the information in the film recreates the 3D image of the clown, smoking the segar. Right

38:12

But the interesting thing about it is; that the clown is three dimension,you can go behind it, you can see if there is

38:19

hairs on the back of his head, you can go underneath, under the chin and beneath. In fact if this hologram had been made, not with ordinary light but if its been made by NMR scan.

38:30

You could have coded on that boundary, on that surface you could have the interiors, you could have all your

38:37

guts and blood and everything else bones, the entire full three dimensional structure would have been mapped.

38:44

You used the word "map" and its a good word. Mapped onto the boundary, on to the film and

38:50

the important thing is; not that you shine light to reconstruct it but that the information about the clown

38:57

is equally well and in fact in some sense better described, more accurately described, more

39:04

preciously described by the little dots and dashes and structures that are entirely scrambled,

39:12

totally impossible for you to just look at, but its there, its there in that film. Its there and as you say; you can add

39:19

detail to that informational film infinitely or is there an upper limit?

39:25

Ok, so in the world that we are talking about which is the real world, there is a limit, no more than one bit,

39:33

and that mean + or -, one little dot per Planck area, a Plank area is a certain unit of area that's made up out of

39:42

the fundamental constants of nature. Its happens to be about 10^-33 cm on a side. its far smaller than anything

39:50

that Physics studied experimentally. But no more; Where did it go? disappeared ..

39:55

Blackholes or something like that - Yeah it went into the blackhole No more than one bit, that means a black dot or a white dot per Planck area. that's just information

40:08

Alright; lets us just backed up for a second. Just as you need a certain amount of resolution

40:15

on a piece of standard film or digital CCD chip to produce an image that's recognizable of your

40:22

lovely pets or you kids or something like that. In Physics one bit of information is a traditional bit as though;

40:30

Yes its a yes or no question -Yes its a yes or no question, so zero one bit, yeah zero/one - is necessary to specify a Plank space which is

40:40

an infinitesimal but measurable little chunk of space. Beyond our ability to measure it at the present; but yes. Alright!

40:49

And so what it says, I mean in essence what its says; is this entire room; every thing that's in it, can be,

40:56

in principle described mathematically in terms of degrees of freedom, structures on the boundaries,

41:03

on the walls of the room with never needing more than one bit of information per Planck area.

41:08

That was very radical, that was very surprising because people always associated information with volume.

41:15

We have another picture but; may be one for a round. Well lets go; No; lets go to; this is the pixel. The pixels in the voxels.

41:22

Ok, let do the pixels voxels, lets think two slides - lets do Vox first First the pixels are artisan, alright, obviously a 2D -Can we jump, can we jump to the other one first

41:31

Alright; we will see the voxels first Ok, - Alright! There is the room, if you like, there is the room and I am gonna describe the room, everything that's in the room,

41:40

like dividing it up into the little tiny cells, lets say no bigger than atom. And what can we ask about a cell?

41:47

We can ask; is their or isn't there an atom in it? Of course we can ask what type of atom but lets ignore that.

41:52

Is their or isn't there an atom in it? and if we don't have to worry about type of an atom, that would be a complete description of everything that's in the room.

42:01

And so there would be one decision for each Voxel, "Voxel" is a word that means a little cube there would be

42:08

one bit of information per Voxel. Its either empty or its full. Alright; so lets divide up this room in each Plank space. -I was talking about atoms but yes;

42:19

Oh I forgot; well in each bigger than Plank space we decided to choose; we are asking a question,

42:24

is there an atom in their? and its Yes or No answer to that, and we will reconstruct the entire space

42:29

in information terms in a cube like this. - Right; and we got some place still around them some

42:35

place just not, I would say probably a lot of Yeses, right? No; many more Noes than Yeses; -You think?

42:41

Oh yeah; room is empty - Yeah its just space mostly empty Yeah; room is almost all empty space - Yeah its always; its noisy, you hear that always but

42:47

yeah, anyway Ok, so now that's the 3D, so whats the other picture?

42:54

Well; what we found in essence, is that's too much information, no room can ever have as much information

43:02

as is implicit in this picture here. The amount of information that it takes to describe the room

43:08

is more like this picture here, one bit of information per surface area.

43:14

So I like to say that world is "Pixelated" not "Voxelated" The world is made up or degrees of freedom

43:21

of the the world; most accurate description we can ever have is in terms of the number of degrees of freedom

43:27

which is proportional to the area not the volume. So its actually the reverse of our intuition

43:33

and Gerard't, help me out here, so we like to think of gosh; you know, movie are grate but wouldn't it be

43:40

fabulous to have IMAX 3D, in fact what Physics says is; You can get all the information in your 3D High Res reality world on a 2D surface.

43:52

Let me just; one thing before I wanna let these guys to answer; the only thing is that the two dimensional

43:59

description is gonna be monstrously scrambled, very difficult to decode, very difficult to see what's its

44:08

a picture of, That's the cost of coding information in two dimension instead of three.

44:16

As a mathematician your first reaction will be; there is much less space of a two dimensional surface

44:24

in any three dimensional world. So your first reaction is; that can't be right, we will be missing enormous

44:30

amounts of information if we try to put or scram everything on a surface, for that we have to remember;

44:38

this is a Planck length which is extremely small to; for all standards. 10^−33 cm is extremely tiny even

44:44

in units of elementary particles. So even this looks at first sight to be very little information,

44:51

actually it is enormous, its gigantic. But on other hand we have to realize;

44:56

that not only what's in this room could be mapped on a surface but entire universe can be mapped

45:03

on the surface, that's even more gigantically crazy because you think that the surface of universe

45:11

would be much smaller than its volume but again this Planck units are so small; its still have enough information on the surface to specify everything that goes on in universe.

45:23

Well; I mean its so counter intuitive, I mean every time I go into the hall in town hall, I wonder how all of Newyork

45:29

could fit in here. But in fact that's kind of what you are saying. So it is very very counter intuitive.

45:36

So you come up with these mathematical conclusions that are very robust and sound and you can defend them,

45:43

I mean do you go back; Herman, to Hawking and does he say; sorry about saying rubbish

45:48

or I guess; I was wrong about the rubbish. To his credit; he has thought of changing at least his opinion and he accepts lot of these ideas.

45:57

Einstein for example; had much harder time accepting quantum mechanics; I don't think he ever did.

46:03

But Hawking; I think, he realize at the time when he was putting this paradox forward that by stating

46:15

the contradiction that was in blackhole Physics, he realize that was a way of making progress.

46:21

And of course he liked annoying his colleagues which is sort of what he was doing by making this particular claim. But he put us to work; so and then; by the time that answers came forward, he has;

46:35

so he had this bet with one his colleagues that I think it was for a year long subscription to playboy

46:41

but in the end; the colleagues decided to give him a nice book instead.

46:47

Because the bet was settled, and then Hawking admitted that information was there; so that's it.

46:57

Well the whole 2D/3D thing if you bring playboy into its a whole that; I know; that's a whole other information space

47:06

- I don't wanna think about it. As a much younger researcher Raphael! what excites you about the holographic principle in terms of;

47:15

and we gonna do its controversy in a moment, in terms of; what it begins to explain about other problems in Physics.

47:24

I thinks what exciting to me is that; the only way that information could possibly not be lost when

47:31

a black hole forms and then evaporates; was for there to be a completely universal relation between

47:38

the information content of a region and its surface area, in other words; there was a relation between

47:45

surfaces in spacetime which are described by gravity theory, that's the realm of Einstein general relativity;

47:52

surfaces surrounding certain regions; those surfaces; their area specify how much information

47:59

could be in the region that was enclosed by them. That turned out to be not the quite the right way of stating it but that was necessary; if information was not going to be lost in blackholes.

48:09

In other words it led to the statement about; how much information there is in the world. That was completely independent of what you was using to encode the information, it didn't matter whether you

48:21

used letters on a page or atoms, or strings, or quarks, what ever your favorite Physical ingredient was.

48:30

It was a statement that was completely universal, if information was preserved then we were learning

48:36

something about fundamentally how much information there is in the world. Even beyond that learning that fundamental - Let me just; let me say one thing just to put an accord

48:45

Its actually not very difficult to understand why this is so; very roughly speaking any place like this room can be

48:52

converted by crashing some shells of matter into it, into a blackhole that has the same surface area, as this room,

48:59

and we know how much information the blackhole contains. So if information is not lost;

49:04

that's means that information in this room; no matter what was here; had to be less to start with than the information of the blackhole or it most equally much and so; its completely universal.

49:14

You don't have to know what we are made of, You don't have to know what the fundamental bits and pieces of Physics are, you already know how much information there is. And so its is a deep relation between

49:23

the two things that we don't know how how to put together, Gravity and Quantum mechanics. Quantum mechanics is about information and gravity is about geometry and surfaces.

49:32

But is it true or is it a distortion to say; and again for me; for a moment here; the idea of going to the blackhole

49:42

Seems to confuse the issue because; the blackhole is interesting; because the way Hawking described it,

49:49

information would be destroyed, that produces the controversy, which create/poses the question alright. What is the relation ship between the information and all of the universe.

49:57

That is exactly why it was one of those questions where; you know; people were just asking incredibly interesting

50:04

questions and as a consequence of resolving it, stumble upon something which was much more general

50:10

and didn't really just holding this particular context of the blackhole, At the end you can throw the blackhole

50:15

away just left with Alright! because I don't think most of people in this room; you know; encounters with blackholes are; you know; monthly at best.

50:23

So lets just say because of the balckhole, thought experiment, controversy, argument with Hawking;

50:34

we have stumbled upon or discovered or now see that; a fundamental feature of the universe is that;

50:44

a two dimensional space of information specifies everything in our universe.

50:50

something like that, it has to that. Well; initially it was clear; how to apply this to the whole universe. Again the context in which it was discovered was a very specific one where;

51:01

you are for away; you throw some elephants into a small region, they form a blackhole and then evaporates. and you want to ask the question by looking at this Hawking radiation that came up; can I figure out

51:11

if it was elephants or zebras that made the blackhole. Now that was resolved I think by now; pretty definitely.

51:17

We can look at this; but our universe is nothing like that, our universe is not like the black hole, our universe is

51:24

not a place where you can go far away, and study Hawking radiation coming out. And nevertheless it turned out to be true that; this was just a tip of the iceberg.

51:34

There is completely universal relation between information and area of surfaces.

51:40

At first it seems like that can't possibly be true, for example: if you don't take the view point of the person

51:46

who waits for the Hawking radiation to fizzle out of the blackhole and then looks carefully at the information

51:52

that is in it. Suppose that I fell in with the other things or with the star that was collapsing in,

51:57

well that star have some information in it; as its collapsing to form a blackhole.

52:04

That information can't disappear, we know from solving the Einstein equations that the surface area of the star

52:12

become smaller and smaller and smaller until its zero at the very end when it hits the singularity

52:18

inside a blackhole. So it seems clear that the amount of information of the star; whatever it is; at some point

52:25

its going to become larger than this smaller and smaller and smaller surface area of the star. It gets more more compressed deep inside the blackhole. So then this mean that; this was just some fluke at it,

52:34

something that applies to particular; you know; observed who live far outside a blackhole. And there is actually

52:39

no general relation between information and surface areas. Well turns out No, if you state the relation in just the right way then its too even deep inside the blackhole

52:49

or in the regions of the universe to the very large, the way you have to state it is actually in much

52:55

more Physical way, as of saying; how much information do I have in this instant of time when my star

53:00

is really small and has very small service area, how much is still inside the star. You have to ask;

53:08

well; if I took a picture of that star at this time, just before its got completely crunch into a singular place

53:18

in spacetime. If I took a picture of it how much of the star would I see. And it turns out that

53:24

You don't have enough time, the light doesn't have enough time to traversed the whole star

53:30

before everything gets crunched into the singularity and the game is over. You have to actually calculate this,

53:36

You have to take my word for it right now, but - I am taking you word for so much But the point is; if you ask, what can actual light ray see? How much information can they see? - Right

53:46

light ray that comes out the area in question and it makes absolutely no difference what area you pick, anywhere in the universe, any shape, doesn't even have to be closed.

53:55

What those light ray see is some piece of the star in this particular example, as by some conspiratorial miracle

54:02

its always less information in that piece o the star than the surface area you started from. Its a much bigger conspiracy of which only a sort of

54:10

tip of the iceberg was discovered in the context of blackhole. Well; its a little bit like uncertainty in the sense that if you try to measure you only gonna get a piece of it

54:19

but that doesn't effect the existence of all the information. Its all there, the fact you can't get it

54:26

or don't have big enough camera is your own personal psychological problem, It doesn't effect the universe at all

54:31

Well; indeed if you wanted to ask how much information is there in the universe than again its actually very

54:38

useful that the information is sort of coded on region that are seen by light rays, You can just ask,

54:44

well; what is in our past, what is in the region from which light could have reached us up until now,

54:51

and that region is bounded by basically the light rays that are just barely making it to you eyes right now,

54:56

and have been traveling for billions of years since the beginning of the universe. And those light rays;

55:01

well; if you follow them back, of course they come from larger and larger region as you follow them back

55:06

that's farther and farther away. But at some point there is surface area actually become very small again;

55:12

when you follow them all the way back to the bigbang, because every thing is small at the bigbang. Universe is basically contracting to the single point at that point.

55:20

So there is a largest area which tells you how much information there is in the Universe, some where between the bigbang and us, that is span by these light rays.

55:28

So we can see exactly what the maximum amount of information there is. So is it; the case on some level that the function of our senses, I mean as; you know; Galileo looked at light rays

55:39

and drew some conclusion about the Universe, are tiny; sort of; instances of the Universe conveying information,

55:47

some thing that's much bigger that we are now extrapolating to extreme states of the Universe,

55:53

either in terms of the very beginning to time with the bigbang or; the sort of; end of matter in a blackhole,

55:58

that they are part of same story a little bit? Well, the interesting thing about the holographic principle, I think all of us probably agree on this is that

56:07

Its a statement that can be made in a situation where we think we understand Physics very well.

56:13

The area that describe how much information there is in the Universe that we see, is not an area that lives

56:20

somewhere very close to bigbang where we might not trust our equations. The area that tells us how much information there is inside of a blackhole is not an area that's somehow close to the singularity

56:29

inside the blackhole, which we don't understand as well as we would like to. These are areas in region of space time that are arbitrarily well understood. They are completely

56:38

harmless. there; you know; Einstien theory implies harmless is good - harmless is always good I mean; I still wouldn't jump into the blackhole but they are very; you know; well understood.

56:48

The whole statement takes place in a regime of Physics that we completely understand.

56:54

But what we don't understand ultimately is why it is true, It seems like a conspiracy. Every time you check

57:01

it works out. And I think that by itself; I think; was a huge piece of support for the idea that information isn't lost.

57:08

All these miracles happen for information not to get lost. It would be funny, if it was at the end But you have me do the case - Funny yeah - HAHAHA -- HAHA -funny -

57:18

-Your sense of humor is not useful to find - Oh I know, yeah Alright, well I love to talk lapses like the next guy but

57:24

So Herman! what is the counter argument here, I mean; I got two questions; one is: what is the counter argument

57:31

Who persists with the idea that this holographic principle may be fun to talk about but in fact doesn't really help us

57:39

or there is another explanation I would necessary say that it might be that people have

57:45

counter argument but right now you can state it as a principle because we have indications that its there

57:52

but again; its basically still from intuitive point of view its absurd that this would be true

58:00

Because again; if we wanna describe what's going on for sure we going to tell Ok, well some thing is happening

58:06

Here at a given time or something is happening there, so essentially the information that you use

58:11

to describe things, for sure grows with the volume. And indeed the equations we are using to describe

58:21

physics and it have all those properties. So right now we don't have a real way of understanding;

58:27

how this is really true, so we know, we have hints that its true

58:32

-There is no evidence. No we don't have a mathematical theory that preciously describe; how it is.

58:39

We have strong evidence that its true, and I think; sort of early time say; early 90s; where, if you would;

58:46

and I think; it was conference in the early 90s where there was a vote, Ok, how many people were believe in

58:52

that the information was lost , and then more than half of the hands went up, and it was very small group of

58:57

people that saying; well we don't believe that information is lost and there was only a couple of people

59:03

-and couple of "rubbish" group And there was yeah the "rubbish" group and then there was the "OK" group Right! and now the "rubbish" group is bigger, its almost

59:11

the whole room - yeah if you call us the "rubbish" group -Well, you were then, you were then Yeah we were called "rubbish" yeah its correct

59:20

and proudly so -and how; I wanna go back to this information and I actually want you to go through those slides that I have seen before, which I think are fascinating but

59:28

Gerard't! let me ask you, is information a particle in the sense that its like matter, its information a kin to being

59:41

like a electrons, protons, quarks, antimatter. Is it some sort of parallel phenomenon that's goes along with

59:49

reality or just something fundamentally different? No actually I think its about time that we try to disagree with each other, and

59:58

-No And so I want to; no you don't -Starting to get good Because I want to bring in a notion which hasn't been

1:00:07

put forward yet. The question of dynamics; you know when I first saw

1:00:13

people windsurfing, I love to also to go windsurfing, so on one day I thought I am theoretical physicist,

1:00:21

I can work out how to stand on the board, how to hold saill without falling over and I worked it all out,

1:00:29

and stood on the board, I could have the sail, and i didn't fall over and I went any direction I want,

1:00:35

except I only solved the static problem, I didn't solved for what happens if a big wave comes.

1:00:41

And what you have to do is you want to make a sudden turn, this I never solved so when ever that happened,

1:00:48

I fell over. Now here the problem is same, so far we have been discussing this static question, what is information, where is it, and so on. You can discuss it at length,

1:00:59

but there is something else in physics, the dynamical question; how things evolve in time and how we phrase

1:01:07

laws of nature. And new we encountered a deep and fundamental problem.

1:01:13

Which is; the world look to us three dimensional, if I make a disturbance here like saying something or

1:01:20

I am shining a light, the disturbance moves with speed of light or slower to its environment and it never goes

1:01:28

faster than speed of light from here to a point far away in Universe. That is a fundamental three dimensional

1:01:34

property of the world as we know. And it is been tested very very accurately in all branches of Physics

1:01:41

Very fundamental principle, not only that disturbances move with certain maximum speed also causality.

1:01:48

That is; when ever you cause some disturbance somewhere it effect never goes faster than

1:01:55

speed of light and certainly doesn't go back in time Now this principle we would like to keep

1:02:01

and now holography is standing in our way, its not doing the thing we want.

1:02:07

If my friend then here, is right; and information on the two dimensional surface is completely scrambled,

1:02:14

how did you explain; if you made a disturbance here, the disturbance doesn't spread faster than speed of light.

1:02:20

How would Leia, when she moves arms in the hologram, how come that these disturbances don't moves faster

1:02:28

than a given speed in her hologram. There's still something basically wrong with the idea.

1:02:34

And that be -Why would they have to move faster than the speed of light to work?

1:02:39

That's relativity theory and relativity theory works extremely well, we don't want to give that up too easily

1:02:47

as a fundamental principle, after all relativity was also a principle that went-ed to Stephen Hawking's derivations

1:02:54

If you throw it away, you are trowing away blackholes as well. So life isn't that easy, there's a problem here. So how do we address that and then

1:03:06

I am coming back to quantum mechanics, say well; we use quantum mechanics from the beginning until

1:03:13

the end. There's something not quite right about the quantum mechanics, and I am been thinking a lot

1:03:19

last decades basically about; there must be something underneath quantum mechanics, some more basic

1:03:27

mechanical system that explains why the world that we encounter today looks like quantum mechanical.

1:03:34

That could solve this problem. Because it could be that in a pre-quantum world,

1:03:40

the world is three dimensional. Information gets lost all the time

1:03:45

In fact a suspicion I have; might practically only one in Universe today that has a suspicion that there's

1:03:54

underline theory in which information gets lost, to such an extent that if you have a bulk of material somewhere,

1:04:02

so much information gets lost, that the only thing you can retain is what sits on the surface.

1:04:08

And that's the reason why; information wise; you have such a thing as holographic principle.

1:04:14

The only amount of information that you can keep; if you have a bucket of water; is what sits on the edge

1:04:20

of the bucket of water. Whats happens to be inside will eventually get lost. Not according to quantum theory because we just realized all quantum theory preserves the information

1:04:30

But it may be a pre-quantum theory in which this information gets lost. -Now this is it, let me to say This pre-quantum theory it could be three dimensional

1:04:37

and then we might possibly find a resolution of this problem.

1:04:42

So is pre-quantum theory, something that happened before the bigbang or its pre-quantum theory;

1:04:51

something that happens before you learned like - I mean pre-quantum in a logical sense It is that some thing, that some fundamental principle lying underneath, the principle of quantum mechanics

1:05:01

-I see Say we have molecules, we have atoms, we have things smaller than atoms but smaller than that are things which might not be quantum mechanical.

1:05:11

That is my premature explanation as how to reconcile the idea that the three dimensional world

1:05:20

seems to be two dimensional by holographic principle, yet there is causality in the three dimensional sense.

1:05:27

This is a problem that has not yet been properly addressed and I think something should be done about this. If we dont, we will never

1:05:36

-Yeah get to work, If we dont, right, if we will never get useful theory - forget homelessness guys come on

1:05:42

powerful enough for the small distances. Well lets; put that to Leonard! is there a possibility of a pre; you know; a more axiomatic kind of pre-quantum

1:05:54

Its a question of axiomatic Alright, but then in some sort of more basic state than quantum mechanics The answer is that; I don't know What you're seeing here is an interesting thing

1:06:05

First of all I would say that it should be clear that this whole holographic story is the most radical thing

1:06:13

that has happened to our understanding of spacetime, matter. Since the invention of quantum mechanics and relativity

1:06:21

It is really some thing very very different. Where is it going? what it is going to explain? How do we explain it.

1:06:31

Well incidentally we all agree largly on what we said up till now and you'll find that Physics in general,

1:06:38

probably in science in general; at any given time there are those things which have been made into established

1:06:44

science, that people agree on and that subset they will tend to agree on unless there's screwballs and outside

1:06:52

the mainstream of the community but then once you go past that, once you go even just a little bit past

1:06:59

What we really know, you will start finding it becoming a very very human subject, subject with

1:07:06

Lets put it this way, good physicists are as variable as snowflake. Every single one of them is different,

1:07:13

every single one of them has a different prospective and once you go past that point where we have confirmation,

1:07:22

where we do agree. you are going to find that just about everybody has a different view of where its gonna go

1:07:28

Sure, that I can understand but lets focus on the radicalism; for a moment; because I think people can understand how relativity radically changed the Newtonian view of reality in the sense that; the

1:07:39

straight lines in the Newtonian world are actually curved in certain spaces and that curvature relates to the force

1:07:46

of gravity in some way and so around stars space actually bends, that's a radical notion.

1:07:52

Its probably only the last thirty years that, that's been internalized to be something that kind of everybody understand. You can't really appreciate the Matrix, movies like the Matrix, unless you sort of understand

1:08:02

the sort of relativistic world. How does this notion produce a radical change;

1:08:10

in the way; that we might see relativity I think it still work in progress and we don't know.

1:08:18

Gerard't has his view, I have my view, Herman has his view, whats his name over there, has his view

1:08:29

And but I tell you if you go out it'll come to you. You go two blocks outside of this room, there's a lot of

1:08:36

people who have no view a lot of people who have no view -Yeah absolutely no view My own view is not all that different than my colleague

1:08:45

over here Its not that I think this is going to be the some deterministic theory that gonna underline quantum mechanics

1:08:52

I think its going to inform how we think about quantum mechanics very deeply and its gonna change

1:08:58

in an enormously big way that we think about quantum mechanics. That I am sure of, whether it will be the way that, Raphael and I have proposed over the last couple

1:09:10

of weeks, on the way, that Hooft has proposed for years. Herman has his ideas

1:09:15

I think that remains to be seen and its a work in progress. I think there'll be progress on it, I think

1:09:21

when we come back here; may be not next year but five years from now, there'll be more knowledge.

1:09:27

But its very clear; we are on the cutting edge of an and on the cusp of,

1:09:34

I think a major Paradigm shift; in the way; the world looks Alright! that's great now, how are we doing, we feeling pretty good about holographic principle and projection

1:09:43

right? right and we are feeling pretty good about how information is a much more complicated thing than

1:09:48

may be the concepts from our intuition right? Ok good, Here's a question that's put you on the spot,

1:09:55

but its relates to your issue of; each of you think differently; the physicist are as different as snowflakes

1:10:02

and hopefully they stick around longer than snowflakes. If I were to put a holographic principle T-shirt

1:10:12

on each one of you that specified how each one of you represents a particular sense of whats gonna happen,

1:10:19

what we are gonna discover, what aspects that represent your position. What would your T-shirt say

1:10:24

I believe in holographic principle and its going to look like blank.

1:10:29

I dont know I would like to have something like; I ❤ HP, or something. but that's gonna be on the back.

1:10:36

The front is gonna have to more To your ticket to quantum gravity on the back, -Quantum so Your ticket to quantum gravity, but why do we

1:10:43

call it a principle. Like you know; I think the positive spin, the most

1:10:49

positive spin I can try to put on this and I am being optimistic when I say: this is; compare this to the

1:10:54

equivalence principle, the equivalence principle is something that; Einstein recognized; you know; a huge

1:11:00

conspiracy in nature, why do all objects fall at the same rate, you know different particles with different charges

1:11:05

do not get attracted to each other at the same rate but with gravity for some reason everything

1:11:11

gets attracted in exactly the same way. Amazing current conspiracy from the point of view of Newtonian theory,

1:11:17

you just have to put it in by hand, doesn't to redact anything but its just crazy, it needs an explanation See, elevates this observation to Universal principle, you have to find a theory that makes this obvious to start

1:11:28

with and that would have to be the quantum gravity because whats involved here is both quantum theory and general relativity, it would have to be the theory that knows about both so its clearly is a signpost,

1:11:39

may be we need more signposts to find the right answer. But for You, holographic principle is a first step towards

1:11:46

a theory of quantum gravity that begins to explain what's so frustrating about gravity.

1:11:51

Well indeed, what Gerard't just said; tells us why its been so hard, you have to explain, where this holographic

1:11:58

bound on information comes from, while not destroying; what we know about locality.

1:12:04

The fact that I get to know is this part of the room, something independently there or I get to move particles around independently seems like you don't have to know whats over there,

1:12:13

to do something here. There seems to be a conflict here between holography and

1:12:18

the way that Physics has worked up until right now. On you T-shirt Herman, what would it say? I mentioned the movie the Matrix, probably something;

1:12:26

some image like these letters and there's Neo, whats his name; the guy who; he goes and he starts flying with

1:12:40

anti gravity. I think that's pretty good. So let me explain why the Matrix, we talked about sort of things;

1:12:47

not being able to move faster than the speed of light. I think the people that came up with the name of the Matrix actually had something pretty good at mind there. Because what is a Matrix; its essentially;

1:12:56

something that relates something that's here with something that's completely somewhere else;

1:13:03

and so I think indeed; that's sort of the future; at least this development; will be that we start actually with

1:13:10

information. So information is going to be our starting point and space-time is not something we start with.

1:13:17

We forget about what space is and what time. And then somehow the information by thinking about; how much

1:13:24

information is; what information is doing then the space-time; what we call be emergent, it will come out of

1:13:31

just a bunch of zeroes and ones. And here is one idea that I think; actually I can put here; just since

1:13:38

no one is listening and I can just say; what I want -They're listening; I guarantee you -There's no non-disclosure thing; so So we talked about information and I wanna know

1:13:48

things; by the way; the information tends to do again, it gets lost all the time; actually that's called the second

1:13:54

law of thermodynamics. The lost information we call it entropy. entropy always increases, chaos increases

1:14:01

and that's a fact that's true in our Universe and its effect, that's true in other Universes as well.

1:14:08

So its very fundamental fact of how things work. And whats also probably also true that; in other

1:14:14

Universes is that; things indeed fall if you drop them they'll go down. And it seems those two facts are very closely related. The fact that information gets lost all the time

1:14:27

And the fact that things fall, so I think that's -lost is different from destroyed?

1:14:34

Lost; when I say lost; indeed its going to be the "known unknown" -Alright got it

1:14:40

known unknown; the increase in known unknowns; that's responsible for space-time, for curvature of space-time,

1:14:50

for gravity. the facts that things fall. I mean; what are you suggesting is that; you know; when

1:14:56

I forgot something, I am instead of just having a kind of pre-senility moment. I am actually participating in a

1:15:03

grand march of our understanding of the Universe. Right that's correct

1:15:08

Yeah that's I am loving, I am glad, I came tonight Gerard't! what would be on you T-shirt or sign that would

1:15:15

suggest where you fall on, and I guess probably the pre-quantum theory, the proto quantum theory that might be

1:15:26

on you t-shirt. That might be the direction that you would be headed. I will continue to ask nasty questions and say well; you know; you can have this fancy beautiful idea

1:15:39

but remember that fundamental principles on which the original idea was based that you are losing out of sight

1:15:46

and so this was why; I mention causality, the fact of the order of cause and events. That is to me a very primary

1:15:57

law or rule of nature. That every thing that happens here has its origin in the past; that's what we call causality.

1:16:06

there's a cause of every thing happening in this world. That's how laws of nature are being formulated.

1:16:13

If you don't have that; you can; for instant; go backward in time and you have circular situations in time;

1:16:20

that you can go and kill you grand father if you could move back in time. That's clearly nonsense and then you

1:16:26

get circular argument and you get chaos in laws of nature themselves. Nature can't solve its own equations

1:16:33

that can not be right we must have the principle of causality

1:16:38

Now this is somewhat at odds with this holographic principle. I don't say to die at odds but add some tangent

1:16:47

here. And what we want the whole reason why we are doing this, while we making this; all these considerations;

1:16:54

is that we want to have a better model, a better theory of what happens in the Physical world

1:17:00

We want to explain why the particles; that you have today; behave as we have seen and studied them

1:17:08

today and there are many things you understand and many things you don't understand We have the standard model of elementary particles; its a beautiful rigid scheme of all particles known today

1:17:20

and it is marvelously precise described by this standard model but there are mysteries in it, which we want to

1:17:26

understand and solve as well. we are very ambitious we've made marvelous theory of nature; its not good

1:17:32

enough. We still know that blanks spot in this theory we want to fill in and this is why we doing this we want to

1:17:41

find new basic principles to improve our understanding of nature, that's what all of this is about.

1:17:46

But the only way to understand or to improve our understanding of nature is what; asking all sort of nasty questions

1:17:55

Questions our colleagues rather not ask because they're so confusing.

1:18:00

Well, lets ask confusing questions anyway; and see if we can come close to answering them.

1:18:06

Any question that has an unexpected answer; might bring us, help us; go forward and make an

1:18:13

improved theory of the world that we live in. Thats what the real reason is; for this exercise

1:18:19

And I love this idea that possibly one way of thinking about causally and forward branch of time is as a

1:18:26

information state, as a sort of a; an understanding of the march of time, as a set of information that; you know;

1:18:38

one event leads to another event. Its a vision that the Universe is very much like

1:18:44

information processing machine, just like your laptop or another computer. I like to view the nature as a

1:18:52

gigantically big computer that has information going into it and information come out processed.

1:18:59

The processors; there are laws of nature. laws of nature is; say that something happens, some

1:19:07

particular configuration goes in. Its being rearranged in other combinations of data goes out.

1:19:13

That's how in Physics; traditionally we consider the process of particles touching and scattering at each other.

1:19:21

Two paths come like this; they hit each other and they go of the reaction. That's we call scattering process

1:19:28

is an important way of describing the laws of nature. What happens when two particles meet, how do they

1:19:34

separate, do they break each other up, do new particles forms, and so on so forth.

1:19:40

So that's a fundamental way of phrasing laws of nature, and that's what we want to understand.

1:19:46

-Can I ask you a question on this. so again; if we talk about pre-quantum mechanics, in quantum mechanics;

1:19:52

we know; that at least one of the foundation of Physics; quantum mechanics has thrown it out of the window.

1:19:57

Because on of the foundations of Physics; was the; if you know what's happening at a certain moment, what the situation is a certain time, than one step later you would know; what happens next.

1:20:08

But in quantum mechanics you have completely identical situation that's a second later would give you

1:20:16

two different outcomes -That is right Is that a principle that you accept or its your pre- quantum mechanics going to be of the type

1:20:25

where you can connect. The principle I accept entirely; within the language of quantum mechanics, but my suspicion is; its only a suspicion; is if quantum mechanics can not be the entire

1:20:37

story. There's something else happening and you are exactly asking the right question; which is how come;

1:20:44

the two particles reach each other; and in the beginning they were identically same; and then suddenly they must

1:20:51

do either this or it might be that or other particles might come out and all that is described by Matrix. In fact;

1:20:58

in quantum mechanical sense and; but nobody knows how to predict what; which or the possibilities

1:21:05

is actually being realized.That I think is a weak spot in our present understanding of quantum mechanics

1:21:11

Why is it impossible to predict in advance; what will happen and there are numerous examples of this

1:21:18

Which are typical for quantum mechanics and physicist today have learned to ignore the problem. to say;

1:21:26

We solve everything except we cannot always predict exactly what happens. What we can say is that you need

1:21:33

all the possibilities to compute what happens after that, so that's a mysterious feature of quantum mechanics.

1:21:39

-And you want to embrace the mystery rather than ignore. Exactly, Ok, they've learned to do that because

1:21:46

it is so successful, it works tremendously well in understanding nature. But it cannot; to my taste;

1:21:54

it cannot be the entire story. There's something else happening but at a different level of nature and my belief

1:22:03

is the plank scale different from the scale of elementary particles that; that could well be the level at which things

1:22:12

are fundamentally different. There you have; if two things scatter, they have only one choice to make

1:22:18

not very much. That's the idea of determinism, which people laugh at; when I mention this idea; people just

1:22:26

manage to keep their smile away from their faces but otherwise; you know; as soon as I am away; I am sure

1:22:32

they are laughing about this idea of determinism. Well; we can check some of the comments on the website later; I think it looks crazier dear, but well, its an old idea

1:22:41

its an old idea, and its proven wrong about a million time and; but always they prove wrong; because they're

1:22:49

making very conservative assumptions and I don't believe those assumptions, so I still think as a way

1:22:55

-Oh nasty question That's very very difficult and its a dispute going on for years and years, starting all the way back with Einstein and Niels Bohr. All historians of science say Einstein

1:23:07

was wrong Bohr was right, and I believe its not true. Oh nasty nasty questions fits on a t-shirt of course

1:23:13

Nasty question does fit on a t-shirt, that's good Leonard! yours? Well; just to respect to what Gerard't says; I would't bet against what he says, on the other hand; I just can't see;

1:23:26

how it will work, but its those kind of conflicts which get us where we want to go. But my t-shirt; well; if you can't

1:23:35

say Brooklyn Bouguer Dodgers I guess I would like at this The UVIR connection, now the reason I bring that; I say that; is to give me an opportunity to explain something else

1:23:48

To give me 5 more minutes to explain something else which we will probably; all agree about, but which is

1:23:55

a very bizarre property of; what the nature; at least if the ideas we are talking about are correct.

1:24:01

Its not totally surprising that as you try to get more and more and more accurate description of nature;

1:24:09

its looks more and more scrambled. To get the best description of nature you have to

1:24:14

account for all the degrees of freedom, and some times it just too much of a good thing; I mean you know;

1:24:19

we know of what happens when you try to have too much information, too much information can lead

1:24:25

to situation where you're just completely confused because you just live with it, -would it be like you take or mount a camera over the city of Newyork to put a light on everybody's head

1:24:35

and over time you specify; where they go. It looks great for about 10 minutes and then its mush

1:24:41

Even taking a sharp snapshot at an instant, too much information will flood you, you know we know; the CIA

1:24:49

gets so much information and them it doesn't know what to do with it and it just get too much.

1:24:54

Its not too surprising; you know; you'd learn much much less about a body of water with a surface and so forth;

1:25:02

if I gave you a description with a table which just gave you the position and the velocity of every single

1:25:10

molecule. That would be an impossible thing to deal with, so its not totally surprising.

1:25:16

Windsurf on that information, yeah Its not totally surprising that the better you try to do in a

1:25:21

better description, the more scramble that's going to look. Whats also new here is something very different than the other situations.

1:25:30

In the other situations getting more and more information usually means more and more detail

1:25:36

about smaller and smaller distances. What I think we now know; is that; at some point that's

1:25:42

going to reverse itself and whats going to happen is when you look in more and more detail, things will start

1:25:48

to look fuzzed out over bigger and bigger distances. And so in the end, the most perfect the most accurate

1:25:55

description and the most scrambled description of something is going to be stretched out over the whole

1:26:02

boundary of space. That's called the UVIR connection and what means; UV stands for ultraviolet, it really just

1:26:11

means small distances. IR stands for infrared and it means very big distances

1:26:17

and we are getting a little bit; I don't say "confused" I am not sure its confused.

1:26:22

But something is happening where as you start to look at a system with more and more and more precision

1:26:29

What you might have thought that you gonna see; more and more tiny short distance small distance precision,

1:26:36

its going to start getting fuzzed out and fuzzed out and fuzzed out until its stretched across the whole

1:26:43

And that's not simply a feature of the camera you are using or resolution that is a fundamental feature.

1:26:50

That's a fundamental aspect of Physics, that better you try to look, and the more detail to try to see with

1:26:56

the more its gonna be stretched out and fuzzed out over bigger and bigger distances. Yeah, I wanna follow up on that; so at least one of the reason why we are now more and more convinced that

1:27:06

holographic principle in really something that works is constantly from string theory; which is my field;

1:27:12

and what happens there is preciously if you go through this step of looking more and more details of what

1:27:18

happens in shorter and shorter distances, you might be interested in; say; what happens inside of our nucleus,

1:27:24

inside of our atoms, and there is nucleus and there are quarks and there are smaller and smaller particles

1:27:31

and suppose again, for a moment; you would wanna forget about gravity, but you start looking more carefully

1:27:38

at what we are made of and then because of this idea that; when you start looking at smaller and smaller scale,

1:27:46

so at least; smaller and smaller distances, suddenly discover that there's actually something new happening

1:27:52

And that something new, at least in terms of your equation; you will recognize it as gravity

1:27:58

So the amazing thing is that what are you actually interested in doing; just looking at the smallest

1:28:04

constituent of matter without pulling gravity in; gravity comes out as something that sort of inevitable.

1:28:13

And to me that's enormously deep lesson there, that; gravity is something that you can not do without.

1:28:20

Clearly we can not do it without it, we would not be sitting here, we would be floating in this, but

1:28:26

Although gravity for me and Stephen Hawking is kind of a pain in the ass sometimes, but; which is why we love

1:28:31

to forget about it but gravity is inevitable but its also a door to this something else.

1:28:38

Its a door to something else but you can get it out of something where you don't put it in.

1:28:44

So its not the starting point, its the output of something. Alright! we're gonna have to ramp this up, lets just

1:28:51

pull the audience; how many of you clap if you think that we are just a projection

1:28:58

Clap if you think if you think we are actually real

1:29:06

and clap if you don't care,

1:29:12

I would have though, that would have gotten the biggest clap of all; this far downtown

1:29:18

First of all; I wanna thank our panel, you have certainly taken us on a great journey tonight

1:29:25

There is obviously so much to think about, I would encourage if you're interested in these ideas;

1:29:31

tomorrow we are actually doing a; rebooting the universe; another exploration of the universe as an information space; at a panel here. I also encourage you on Sunday; in the Kimmel space upstairs.

1:29:43

Mary Simon and Keystone dancers are going to be doing a fabulous; sort of mapping of dance; on to the

1:29:51

messier catalog and objects in the Universe to this idea of one information space mapping on to another as a

1:29:59

theme here at the world science festival. I encourage to explore all of it. Thank you so much for coming and thanks to the panel