Lecture 8 | String Theory and M-Theory

(November 8, 2010) Professor Leonard Susskind covers the history of path/surface integrals; conformal mapping; application of conformal mapping in string scattering.
String theory (with its close relative, M-theory) is the basis for the most ambitious theories of the physical world. It has profoundly influenced our understanding of gravity, cosmology, and particle physics. In this course we will develop the basic theoretical and mathematical ideas, including the string-theoretic origin of gravity, the theory of extra dimensions of space, the connection between strings and black holes, the "landscape" of string theory, and the holographic principle.
This course was originally presented in Stanford's Continuing Studies program.
Stanford University:
www.stanford.edu/
Stanford Continuing Studies Program:
csp.stanford.edu/
Stanford University Channel on KZbin:
/ stanford

[@mihirbpi]

Wow this is the best explanation of analytic/conformal complex functions I've ever seen and it's from a physics course not a complex analysis course. Amazing how examples and teaching style makes so much difference.

[@joabrosenberg2961]

Conformal mapping; Cauchy Rieman equations 25:00; Examples 36:00; LogZ in String theory 50:00; Path Integral in 26 dimensions 1:10:00; Injecting the incoming particles 1:19:00;

[@GauravYadav-rd1dk]

this video really helped me to understand conformal mapping... Hattss offf to Proff Leonard Susskind... U r a man of jewels....

[@sterbenthanatos8549]

"It's a sphere because when you take limits things go around." Pure genius.

[@brendawilliams8062]

If you like the 312 and 311 thing.

[@perjespersen4746]

14:58 Yeah, my two year old keeps saying "delta" even if he is clearly talking about infinitesimals.

[@petergreen5337]

❤Thank you very much Professor and class

[@ayadiv]

Yes, You are right. I've recognised the same mistake, but I think it is not crucial here.

[@DanielE15]

I put this on to sleep. Love it.

[@bobbobson6867]

Same. 👍.

[@pedroakjr2371]

I watch this during my evening snacks. I'm either here or watching some random dude opening packs of pokemon cards.

[@JonathanTot]

"Cauchy made calculus rigourous." Susskind "That you dont need credit for." like a boss! ROFLMAO

[@guynouri]

When’s the movie coming out? And whose playing Quanta!?

[@Dilaton100]

@luzzie9 You need the math if You want to understannd and appreciate it at a deeper (not only popular) level ;-) ,,,

[@brendawilliams8062]

Thankyou.

[@erggish]

Cauchy-Schwarz inequality :P

[@perjespersen4746]

21:00 bijective

[@PMaldeev]

"...let's calculate delta w by delta z... well, let's not be babies, let's call it dw by dz" "...all sorts of names: meromorphic, holomorphic; I never understood what they meant...there's fancy names for everything"

[@drdca8263]

Ok, so, uh, Like I was wondering when I first watched this series like a year ago, what if we just, take the solution that we get in 26 dimensions, with the whole electrostatics problem thing, And then get rid of all but 4 of the dimensions in that, And then do the integrating? I get that the integrals in the place it comes from end up with infinity if you don’t have 26 or 10 or whatever, But what happens if you pretend that it does give you the thing with the electrostatics, and see what results that gives? Also, wait, does the scattering amplitude only depend on the momenta of the particles? Shouldn’t the relative positions of the particles matter in some way? Or is this just in the “assume there is a head-on collision, and use the center of mass frame” case?

[@BPHAbishekP]

refer previous lectures ,it also depends on relative position ,angle of scattering

[@drdca8263]

@@BPHAbishekP Thank you.

[@qwadratix]

Two strings enter and two strings leave...

[@massimoandretta3529]

"meromorphic, holomorphic..." Prof. Sussikind is very clever and a genius in math and physics, but noy in ancient Greek !

[@TheEmaxya]

That's pity that Leo is doing mistakes like in this lecture - the linear fractional transformation maps the left plane to the disk.

[@tataltsal]

Just invert the expression

[@user-fc8xw4fi5v]

whatever thats a lame example anyways

[@davidwilkie9551]

Excellent lecture. Lots of 0-1-2-ness dimensionality correspondence and implied algebra of orthogonal-normal axial-tangential higher conformity. Tell the pre-meds we absolutely live, mind-body, in Calculus, pure-math relative-timing pulse-evolution log-antilog superposition-> bio-logically.

[@brendawilliams8062]

Some people meet back here from time to time. The Educator is excellent and is a good reason to return.

[@JonathanTot]

i couldn't believe my ears when the guys asked "Is there a curl in two dimensions?" 2nd year university calculus, green's theorem, the first big thing in the course where I learned it

[@while_coyote]

Whoever that guy is who says "holomorphic is analytic" is constantly interrupting *every lecture in this series* with his inane "helpful" questions and statements, and it's aggravating. Shuuuut uuuup, you're not as interesting as you think you are and you're ruining the continuity of the lecture for others.

[@yazdanadzi]

truth has been spoken -_-

[@rshaochu]

this guy is unbelievably annoying; amazing that dr susskind actually tolerates his interruptions...

[@deweyspangler8472]

This is an example of the nerd that was in every class that I took and taught. They just don't get that NO ONE cares what they think.

[@lucasthompson1650]

Did anyone even consider he might be a TA given that Lenny always seems to look in the same direction when he's grasping for words and tends to nod when he talks to that one voice, who hardly asks any questions but instead always tries to offer clarifications (albeit, occasionally erroneously). Lenny doesn't suffer fools, anyone who has ever met him knows that.

[@lucasthompson1650]

A comment on the following video made another hypothesis, that's the guy who brings the cookies so Lenny isn't tearing him a new asshole. 😎

[@brendawilliams8062]

Some 125 thing

[@mohamedtawfeeq8524]

has anyone got this far ?

[@Fritzbedeek]

+Mohamed TawfeeQ , OKay finally made it here. :)

[@mohamedtawfeeq8524]

Fritzbedeek amazing, keep up the good work

[@Fritzbedeek]

Mohamed TawfeeQ Are you finished now?

[@mohamedtawfeeq8524]

Fritzbedeek yes. although I only understood about 30% only due to my lack of knowledge of quantum mechanics

[@Fritzbedeek]

I find i go over previous material or other math lectures then rewatch Susskind. Then I realize he has explained it thoroughly but it just took me a while to catch on. These or a nearly never ending source of learning to me. Most enjoyable.

[@isodoublet]

Great course, but so many stupid questions and unrequested interruptions. Ugh.

[@tataltsal]

Because they paid for the course

[@isodoublet]

@@jay.u Lots of questions are stupid, particularly when the asker is doing it for attention.

[@isodoublet]

@@jay.u "I know someone like that guy" So do I. Many such cases. "they’re not doing it for attention" Yes they are. "Plus, since they paid for the lectures" So did everybody else who had to sit through his interludes.

[@mrchangcooler]

I'll play you a tune on the world's smallest violin. It's a class where students ask questions for clarifications, not your personal lecture. Get over it, brat.

[@isodoublet]

@@mrchangcooler He's not asking questions for clarification. He's showing off how smart he thinks he is. I bet you're one of those types too.

[@maneldias6221]

that suss kinda suss

[@rmerkle1]

Type "True Theory of Everything Quadrant Model of Reality 1" into KZbin for the Truth.